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From: "Wang, Jian J" <jian.j.wang@intel.com>
To: "Vang, Judah" <judah.vang@intel.com>,
	"devel@edk2.groups.io" <devel@edk2.groups.io>
Cc: "Gao, Liming" <gaoliming@byosoft.com.cn>,
	"Wu, Hao A" <hao.a.wu@intel.com>,
	"Mistry, Nishant C" <nishant.c.mistry@intel.com>
Subject: Re: [PATCH v5 08/19] MdeModulePkg: Add support for Protected Variables
Date: Mon, 14 Nov 2022 07:14:26 +0000	[thread overview]
Message-ID: <MW4PR11MB6763AE595973FDC2895D73ACB6059@MW4PR11MB6763.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20221106073509.3071-9-judah.vang@intel.com>

Hi Judah,

Just one comment:

For all header files, no need to remove the opening '_' of include guard macro.
Protected variable code are now in different folder than original variable driver.
They won't reference code from each other. Please add the opening '_' for those
macros to confirm to edk2 coding convention.

Regards,
Jian

> -----Original Message-----
> From: Vang, Judah <judah.vang@intel.com>
> Sent: Sunday, November 06, 2022 3:35 PM
> To: devel@edk2.groups.io
> Cc: Wang, Jian J <jian.j.wang@intel.com>; Gao, Liming
> <gaoliming@byosoft.com.cn>; Wu, Hao A <hao.a.wu@intel.com>; Mistry,
> Nishant C <nishant.c.mistry@intel.com>
> Subject: [PATCH v5 08/19] MdeModulePkg: Add support for Protected Variables
> 
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2594
> 
> V5: Add RuntimeDxe Variable Protection into a new directory and
> keep existing Variable for RuntimeDxe unchanged.
> 
> v4: Applied code review - remove unreferenced library from .inf.
> Updated some function description and parameters.
> 
> V3: Fix 'NextVariableStore' parameter for CopyMem.  It was causing
> an exception. Need to correctly cast 'NextVariableStore' so all
> platforms build.  Add code to initialize 'ContextIn' structure in
> SmmVariableReay() to fix issue with NULL function pointer.
> 
> V1: Add support for Protected Variables.
> Add new API to retrieve Variable Infomation and data.
> Add new API to update variable in non-volatile storage or
> cached copy.
> 
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Cc: Liming Gao <gaoliming@byosoft.com.cn>
> Cc: Hao A Wu <hao.a.wu@intel.com>
> Cc: Nishant C Mistry <nishant.c.mistry@intel.com>
> Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
> Signed-off-by: Nishant C Mistry <nishant.c.mistry@intel.com>
> Signed-off-by: Judah Vang <judah.vang@intel.com>
> ---
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/RuntimeDxeUnitTes
> t/VariableLockRequestToLockUnitTest.inf |   36 +
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeDxe
> .inf                                   |  151 +
>  MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmm.inf
> |  153 +
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmRuntim
> eDxe.inf                                |  119 +
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableStandalone
> Mm.inf                                 |  143 +
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/PrivilegePolymorphi
> c.h                                   |  158 +
>  MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/Variable.h
> |  948 +++++
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableNonVolatile
> .h                                    |   67 +
>  MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableParsing.h
> |  424 ++
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeCac
> he.h                                   |   51 +
>  MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/Measurement.c
> |  343 ++
>  MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/Reclaim.c
> |  504 +++
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/RuntimeDxeUnitTes
> t/VariableLockRequestToLockUnitTest.c   |  607 +++
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/SpeculationBarrierD
> xe.c                                  |   27 +
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/SpeculationBarrierS
> mm.c                                  |   26 +
>  MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/TcgMorLockDxe.c
> |  153 +
>  MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/TcgMorLockSmm.c
> |  569 +++
>  MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VarCheck.c
> |  101 +
>  MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/Variable.c
> | 4037 ++++++++++++++++++++
>  MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableDxe.c
> |  670 ++++
>  MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableExLib.c
> |  417 ++
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableLockReques
> tToLock.c                              |   96 +
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableNonVolatile
> .c                                    |  537 +++
>  MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableParsing.c
> | 1110 ++++++
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariablePolicySmm
> Dxe.c                                   |  575 +++
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeCac
> he.c                                   |  158 +
>  MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmm.c
> | 1268 ++++++
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmRuntim
> eDxe.c                                  | 1895 +++++++++
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableStandalone
> Mm.c                                   |   89 +
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableTraditional
> Mm.c                                  |  130 +
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeDxe
> .uni                                   |   22 +
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeDxe
> Extra.uni                              |   14 +
>  MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmm.uni
> |   27 +
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmExtra.u
> ni                                     |   14 +
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmRuntim
> eDxe.uni                                |   23 +
> 
> MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmRuntim
> eDxeExtra.uni                           |   14 +
>  36 files changed, 15676 insertions(+)
> 
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/RuntimeDxeUnitT
> est/VariableLockRequestToLockUnitTest.inf
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/RuntimeDxeUnitT
> est/VariableLockRequestToLockUnitTest.inf
> new file mode 100644
> index 000000000000..586d877fca90
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/RuntimeDxeUnitT
> est/VariableLockRequestToLockUnitTest.inf
> @@ -0,0 +1,36 @@
> +## @file
> +# This is a host-based unit test for the VariableLockRequestToLock shim.
> +#
> +# Copyright (c) Microsoft Corporation.
> +# SPDX-License-Identifier: BSD-2-Clause-Patent
> +##
> +
> +[Defines]
> +  INF_VERSION         = 0x00010017
> +  BASE_NAME           = VariableLockRequestToLockUnitTest
> +  FILE_GUID           = A657FCD8-4A0D-46B4-8DC9-F089626383AD
> +  VERSION_STRING      = 1.0
> +  MODULE_TYPE         = HOST_APPLICATION
> +
> +#
> +# The following information is for reference only and not required by the build
> tools.
> +#
> +#  VALID_ARCHITECTURES           = IA32 X64 ARM AARCH64
> +#
> +
> +[Sources]
> +  VariableLockRequestToLockUnitTest.c
> +  ../VariableLockRequestToLock.c
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +  MdeModulePkg/MdeModulePkg.dec
> +  UnitTestFrameworkPkg/UnitTestFrameworkPkg.dec
> +
> +[LibraryClasses]
> +  UnitTestLib
> +  DebugLib
> +  VariablePolicyLib
> +  VariablePolicyHelperLib
> +  BaseMemoryLib
> +  MemoryAllocationLib
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeD
> xe.inf
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeD
> xe.inf
> new file mode 100644
> index 000000000000..6adc2c636e84
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeD
> xe.inf
> @@ -0,0 +1,151 @@
> +## @file
> +#  Provides variable service.
> +#
> +#  This module installs variable arch protocol and variable write arch protocol
> to provide
> +#  variable services: SetVariable, GetVariable, GetNextVariableName and
> QueryVariableInfo.
> +#
> +#  Caution: This module requires additional review when modified.
> +#  This driver will have external input - variable data.
> +#  This external input must be validated carefully to avoid security issues such
> as
> +#  buffer overflow or integer overflow.
> +#
> +# Copyright (c) 2006 - 2022, Intel Corporation. All rights reserved.<BR>
> +# Copyright (c) Microsoft Corporation.
> +# SPDX-License-Identifier: BSD-2-Clause-Patent
> +#
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 0x00010005
> +  BASE_NAME                      = VariableRuntimeDxe
> +  MODULE_UNI_FILE                = VariableRuntimeDxe.uni
> +  FILE_GUID                      = 146F4448-56BF-405C-A8C4-B77FFD24BE00
> +  MODULE_TYPE                    = DXE_RUNTIME_DRIVER
> +  VERSION_STRING                 = 1.0
> +  ENTRY_POINT                    = VariableServiceInitialize
> +
> +#
> +# The following information is for reference only and not required by the build
> tools.
> +#
> +#  VALID_ARCHITECTURES           = IA32 X64 EBC
> +#
> +#  VIRTUAL_ADDRESS_MAP_CALLBACK  =  VariableClassAddressChangeEvent
> +#
> +
> +[Sources]
> +  Reclaim.c
> +  Variable.c
> +  VariableDxe.c
> +  Variable.h
> +  VariableNonVolatile.c
> +  VariableNonVolatile.h
> +  VariableParsing.c
> +  VariableParsing.h
> +  VariableRuntimeCache.c
> +  VariableRuntimeCache.h
> +  PrivilegePolymorphic.h
> +  Measurement.c
> +  TcgMorLockDxe.c
> +  VarCheck.c
> +  VariableExLib.c
> +  SpeculationBarrierDxe.c
> +  VariableLockRequestToLock.c
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +  MdeModulePkg/MdeModulePkg.dec
> +
> +[LibraryClasses]
> +  MemoryAllocationLib
> +  BaseLib
> +  SynchronizationLib
> +  UefiLib
> +  UefiBootServicesTableLib
> +  BaseMemoryLib
> +  DebugLib
> +  UefiRuntimeLib
> +  DxeServicesTableLib
> +  UefiDriverEntryPoint
> +  PcdLib
> +  HobLib
> +  TpmMeasurementLib
> +  AuthVariableLib
> +  VarCheckLib
> +  VariableFlashInfoLib
> +  VariablePolicyLib
> +  VariablePolicyHelperLib
> +  SafeIntLib
> +  ProtectedVariableLib
> +
> +[Protocols]
> +  gEfiFirmwareVolumeBlockProtocolGuid           ## CONSUMES
> +  ## CONSUMES
> +  ## NOTIFY
> +  gEfiFaultTolerantWriteProtocolGuid
> +  gEfiVariableWriteArchProtocolGuid             ## PRODUCES
> +  gEfiVariableArchProtocolGuid                  ## PRODUCES
> +  gEdkiiVariableLockProtocolGuid                ## PRODUCES
> +  gEdkiiVariablePolicyProtocolGuid              ## CONSUMES
> +  gEdkiiVarCheckProtocolGuid                    ## PRODUCES
> +
> +[Guids]
> +  ## SOMETIMES_CONSUMES   ## GUID # Signature of Variable store header
> +  ## SOMETIMES_PRODUCES   ## GUID # Signature of Variable store header
> +  ## SOMETIMES_CONSUMES   ## HOB
> +  ## SOMETIMES_PRODUCES   ## SystemTable
> +  gEfiAuthenticatedVariableGuid
> +
> +  ## SOMETIMES_CONSUMES   ## GUID # Signature of Variable store header
> +  ## SOMETIMES_PRODUCES   ## GUID # Signature of Variable store header
> +  ## SOMETIMES_CONSUMES   ## HOB
> +  ## SOMETIMES_PRODUCES   ## SystemTable
> +  gEfiVariableGuid
> +
> +  ## SOMETIMES_CONSUMES   ## Variable:L"PlatformLang"
> +  ## SOMETIMES_PRODUCES   ## Variable:L"PlatformLang"
> +  ## SOMETIMES_CONSUMES   ## Variable:L"Lang"
> +  ## SOMETIMES_PRODUCES   ## Variable:L"Lang"
> +  ## SOMETIMES_CONSUMES   ## Variable:L"PK"
> +  ## SOMETIMES_CONSUMES   ## Variable:L"KEK"
> +  ## SOMETIMES_CONSUMES   ## Variable:L"SecureBoot"
> +  gEfiGlobalVariableGuid
> +
> +  gEfiMemoryOverwriteControlDataGuid            ## SOMETIMES_CONSUMES   ##
> Variable:L"MemoryOverwriteRequestControl"
> +  gEfiMemoryOverwriteRequestControlLockGuid     ## SOMETIMES_PRODUCES
> ## Variable:L"MemoryOverwriteRequestControlLock"
> +
> +  gEfiEventVirtualAddressChangeGuid             ## CONSUMES             ## Event
> +  gEfiSystemNvDataFvGuid                        ## CONSUMES             ## GUID
> +  gEfiEndOfDxeEventGroupGuid                    ## CONSUMES             ## Event
> +  gEdkiiFaultTolerantWriteGuid                  ## SOMETIMES_CONSUMES   ## HOB
> +
> +  ## SOMETIMES_CONSUMES   ## Variable:L"VarErrorFlag"
> +  ## SOMETIMES_PRODUCES   ## Variable:L"VarErrorFlag"
> +  gEdkiiVarErrorFlagGuid
> +
> +  ## SOMETIMES_CONSUMES   ## Variable:L"db"
> +  ## SOMETIMES_CONSUMES   ## Variable:L"dbx"
> +  ## SOMETIMES_CONSUMES   ## Variable:L"dbt"
> +  gEfiImageSecurityDatabaseGuid
> +
> +[Pcd]
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdMaxVariableSize                 ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdMaxAuthVariableSize             ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdMaxVolatileVariableSize         ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdMaxHardwareErrorVariableSize    ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdVariableStoreSize               ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdHwErrStorageSize                ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdMaxUserNvVariableSpaceSize
> ## CONSUMES
> +
> gEfiMdeModulePkgTokenSpaceGuid.PcdBoottimeReservedNvVariableSpaceSize
> ## CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdReclaimVariableSpaceAtEndOfDxe  ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdEmuVariableNvModeEnable         ##
> SOMETIMES_CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdEmuVariableNvStoreReserved      ##
> SOMETIMES_CONSUMES
> +
> +[FeaturePcd]
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdVariableCollectStatistics  ##
> CONSUMES # statistic the information of variable.
> +  gEfiMdePkgTokenSpaceGuid.PcdUefiVariableDefaultLangDeprecate ##
> CONSUMES # Auto update PlatformLang/Lang
> +
> +[Depex]
> +  TRUE
> +
> +[UserExtensions.TianoCore."ExtraFiles"]
> +  VariableRuntimeDxeExtra.uni
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmm.inf
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmm.inf
> new file mode 100644
> index 000000000000..2651ec514df3
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmm.inf
> @@ -0,0 +1,153 @@
> +## @file
> +#  Provides SMM variable service.
> +#
> +#  This module installs SMM variable protocol into SMM protocol database,
> +#  which can be used by SMM driver, and installs SMM variable protocol
> +#  into BS protocol database, which can be used to notify the SMM Runtime
> +#  Dxe driver that the SMM variable service is ready.
> +#  This module should be used with SMM Runtime DXE module together. The
> +#  SMM Runtime DXE module would install variable arch protocol and variable
> +#  write arch protocol based on SMM variable module.
> +#
> +#  Caution: This module requires additional review when modified.
> +#  This driver will have external input - variable data and communicate buffer in
> SMM mode.
> +#  This external input must be validated carefully to avoid security issues such
> as
> +#  buffer overflow or integer overflow.
> +#    The whole SMM authentication variable design relies on the integrity of
> flash part and SMM.
> +#  which is assumed to be protected by platform.  All variable code and
> metadata in flash/SMM Memory
> +#  may not be modified without authorization. If platform fails to protect these
> resources,
> +#  the authentication service provided in this driver will be broken, and the
> behavior is undefined.
> +#
> +# Copyright (c) 2010 - 2022, Intel Corporation. All rights reserved.<BR>
> +# Copyright (c) Microsoft Corporation.
> +# SPDX-License-Identifier: BSD-2-Clause-Patent
> +#
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 0x00010005
> +  BASE_NAME                      = VariableSmm
> +  MODULE_UNI_FILE                = VariableSmm.uni
> +  FILE_GUID                      = 1C32FDDF-7FF1-4EE5-BDA0-ED9AAC623D3C
> +  MODULE_TYPE                    = DXE_SMM_DRIVER
> +  VERSION_STRING                 = 1.0
> +  PI_SPECIFICATION_VERSION       = 0x0001000A
> +  ENTRY_POINT                    = VariableServiceInitialize
> +
> +#
> +# The following information is for reference only and not required by the build
> tools.
> +#
> +#  VALID_ARCHITECTURES           = IA32 X64
> +#
> +
> +
> +[Sources]
> +  Reclaim.c
> +  Variable.c
> +  VariableTraditionalMm.c
> +  VariableSmm.c
> +  VariableNonVolatile.c
> +  VariableNonVolatile.h
> +  VariableParsing.c
> +  VariableParsing.h
> +  VariableRuntimeCache.c
> +  VariableRuntimeCache.h
> +  VarCheck.c
> +  Variable.h
> +  PrivilegePolymorphic.h
> +  VariableExLib.c
> +  TcgMorLockSmm.c
> +  SpeculationBarrierSmm.c
> +  VariableLockRequestToLock.c
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +  MdeModulePkg/MdeModulePkg.dec
> +
> +[LibraryClasses]
> +  UefiDriverEntryPoint
> +  MemoryAllocationLib
> +  BaseLib
> +  SynchronizationLib
> +  UefiLib
> +  MmServicesTableLib
> +  BaseMemoryLib
> +  DebugLib
> +  DxeServicesTableLib
> +  HobLib
> +  PcdLib
> +  SmmMemLib
> +  AuthVariableLib
> +  VarCheckLib
> +  UefiBootServicesTableLib
> +  VariableFlashInfoLib
> +  VariablePolicyLib
> +  VariablePolicyHelperLib
> +  SafeIntLib
> +  ProtectedVariableLib
> +
> +[Protocols]
> +  gEfiSmmFirmwareVolumeBlockProtocolGuid        ## CONSUMES
> +  ## CONSUMES
> +  ## NOTIFY
> +  gEfiSmmFaultTolerantWriteProtocolGuid
> +  ## PRODUCES
> +  ## UNDEFINED # SmiHandlerRegister
> +  gEfiSmmVariableProtocolGuid
> +  gEfiMmEndOfDxeProtocolGuid                    ## NOTIFY
> +  gEdkiiSmmVarCheckProtocolGuid                 ## PRODUCES
> +  gEfiTcgProtocolGuid                           ## SOMETIMES_CONSUMES
> +  gEfiTcg2ProtocolGuid                          ## SOMETIMES_CONSUMES
> +
> +[Guids]
> +  ## SOMETIMES_CONSUMES   ## GUID # Signature of Variable store header
> +  ## SOMETIMES_PRODUCES   ## GUID # Signature of Variable store header
> +  ## SOMETIMES_CONSUMES   ## HOB
> +  ## SOMETIMES_PRODUCES   ## SystemTable
> +  gEfiAuthenticatedVariableGuid
> +
> +  ## SOMETIMES_CONSUMES   ## GUID # Signature of Variable store header
> +  ## SOMETIMES_PRODUCES   ## GUID # Signature of Variable store header
> +  ## SOMETIMES_CONSUMES   ## HOB
> +  ## SOMETIMES_PRODUCES   ## SystemTable
> +  gEfiVariableGuid
> +
> +  ## SOMETIMES_CONSUMES   ## Variable:L"PlatformLang"
> +  ## SOMETIMES_PRODUCES   ## Variable:L"PlatformLang"
> +  ## SOMETIMES_CONSUMES   ## Variable:L"Lang"
> +  ## SOMETIMES_PRODUCES   ## Variable:L"Lang"
> +  gEfiGlobalVariableGuid
> +
> +  gEfiMemoryOverwriteControlDataGuid            ## SOMETIMES_CONSUMES   ##
> Variable:L"MemoryOverwriteRequestControl"
> +  gEfiMemoryOverwriteRequestControlLockGuid     ## SOMETIMES_PRODUCES
> ## Variable:L"MemoryOverwriteRequestControlLock"
> +
> +  gSmmVariableWriteGuid                         ## PRODUCES             ## GUID # Install
> protocol
> +  gEfiSystemNvDataFvGuid                        ## CONSUMES             ## GUID
> +  gEdkiiFaultTolerantWriteGuid                  ## SOMETIMES_CONSUMES   ## HOB
> +
> +  ## SOMETIMES_CONSUMES   ## Variable:L"VarErrorFlag"
> +  ## SOMETIMES_PRODUCES   ## Variable:L"VarErrorFlag"
> +  gEdkiiVarErrorFlagGuid
> +
> +[Pcd]
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdMaxVariableSize                  ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdMaxAuthVariableSize              ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdMaxVolatileVariableSize          ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdMaxHardwareErrorVariableSize     ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdVariableStoreSize                ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdHwErrStorageSize                 ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdMaxUserNvVariableSpaceSize
> ## CONSUMES
> +
> gEfiMdeModulePkgTokenSpaceGuid.PcdBoottimeReservedNvVariableSpaceSize
> ## CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdReclaimVariableSpaceAtEndOfDxe
> ## CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdEmuVariableNvModeEnable          ##
> SOMETIMES_CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdEmuVariableNvStoreReserved       ##
> SOMETIMES_CONSUMES
> +
> +[FeaturePcd]
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdVariableCollectStatistics        ##
> CONSUMES  # statistic the information of variable.
> +  gEfiMdePkgTokenSpaceGuid.PcdUefiVariableDefaultLangDeprecate       ##
> CONSUMES  # Auto update PlatformLang/Lang
> +
> +[Depex]
> +  TRUE
> +
> +[UserExtensions.TianoCore."ExtraFiles"]
> +  VariableSmmExtra.uni
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmRunt
> imeDxe.inf
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmRunt
> imeDxe.inf
> new file mode 100644
> index 000000000000..0d169913c9c9
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmRunt
> imeDxe.inf
> @@ -0,0 +1,119 @@
> +## @file
> +#  Runtime DXE part corresponding to SMM authenticated variable module.
> +#
> +#  This module installs variable arch protocol and variable write arch protocol
> to provide
> +#  variable service. This module need work together with SMM authenticated
> variable module.
> +#
> +#  Caution: This module requires additional review when modified.
> +#  This driver will have external input - variable data.
> +#  This external input must be validated carefully to avoid security issues such
> as
> +#  buffer overflow or integer overflow.
> +#    The whole SMM authentication variable design relies on the integrity of
> flash part and SMM.
> +#  which is assumed to be protected by platform.  All variable code and
> metadata in flash/SMM Memory
> +#  may not be modified without authorization. If platform fails to protect these
> resources,
> +#  the authentication service provided in this driver will be broken, and the
> behavior is undefined.
> +#
> +# Copyright (c) 2010 - 2022, Intel Corporation. All rights reserved.<BR>
> +# Copyright (c) Microsoft Corporation.<BR>
> +# SPDX-License-Identifier: BSD-2-Clause-Patent
> +#
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 0x00010005
> +  BASE_NAME                      = VariableSmmRuntimeDxe
> +  MODULE_UNI_FILE                = VariableSmmRuntimeDxe.uni
> +  FILE_GUID                      = 3C9DF4B3-559F-4AE4-AEA3-E4B0C3D9D3EE
> +  MODULE_TYPE                    = DXE_RUNTIME_DRIVER
> +  VERSION_STRING                 = 1.0
> +  ENTRY_POINT                    = VariableSmmRuntimeInitialize
> +
> +#
> +# The following information is for reference only and not required by the build
> tools.
> +#
> +#  VALID_ARCHITECTURES           = IA32 X64
> +#
> +#  VIRTUAL_ADDRESS_MAP_CALLBACK  =  VariableAddressChangeEvent
> +#
> +
> +[Sources]
> +  VariableSmmRuntimeDxe.c
> +  PrivilegePolymorphic.h
> +  Measurement.c
> +  VariableParsing.c
> +  VariableParsing.h
> +  Variable.h
> +  VariablePolicySmmDxe.c
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +  MdeModulePkg/MdeModulePkg.dec
> +
> +[LibraryClasses]
> +  MemoryAllocationLib
> +  BaseLib
> +  UefiBootServicesTableLib
> +  DebugLib
> +  UefiRuntimeLib
> +  DxeServicesTableLib
> +  UefiDriverEntryPoint
> +  TpmMeasurementLib
> +  SafeIntLib
> +  PcdLib
> +  MmUnblockMemoryLib
> +  ProtectedVariableLib
> +
> +[Protocols]
> +  gEfiVariableWriteArchProtocolGuid             ## PRODUCES
> +  gEfiVariableArchProtocolGuid                  ## PRODUCES
> +  gEfiMmCommunication2ProtocolGuid              ## CONSUMES
> +  ## CONSUMES
> +  ## NOTIFY
> +  ## UNDEFINED # Used to do smm communication
> +  gEfiSmmVariableProtocolGuid
> +  gEdkiiVariableLockProtocolGuid                ## PRODUCES
> +  gEdkiiVarCheckProtocolGuid                    ## PRODUCES
> +  gEdkiiVariablePolicyProtocolGuid              ## PRODUCES
> +
> +[FeaturePcd]
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdEnableVariableRuntimeCache
> ## CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdVariableCollectStatistics            ##
> CONSUMES
> +
> +[Pcd]
> +
> gEfiMdeModulePkgTokenSpaceGuid.PcdAllowVariablePolicyEnforcementDisable
> ## CONSUMES
> +
> +[Guids]
> +  ## PRODUCES             ## GUID # Signature of Variable store header
> +  ## CONSUMES             ## GUID # Signature of Variable store header
> +  ## SOMETIMES_PRODUCES   ## SystemTable
> +  gEfiAuthenticatedVariableGuid
> +
> +  ## PRODUCES             ## GUID # Signature of Variable store header
> +  ## CONSUMES             ## GUID # Signature of Variable store header
> +  ## SOMETIMES_PRODUCES   ## SystemTable
> +  gEfiVariableGuid
> +
> +  gEfiEventVirtualAddressChangeGuid             ## CONSUMES ## Event
> +  gEfiEventExitBootServicesGuid                 ## CONSUMES ## Event
> +  ## CONSUMES ## GUID # Locate protocol
> +  ## CONSUMES ## GUID # Protocol notify
> +  gSmmVariableWriteGuid
> +
> +  ## SOMETIMES_CONSUMES   ## Variable:L"PK"
> +  ## SOMETIMES_CONSUMES   ## Variable:L"KEK"
> +  ## SOMETIMES_CONSUMES   ## Variable:L"SecureBoot"
> +  gEfiGlobalVariableGuid
> +
> +  ## SOMETIMES_CONSUMES   ## Variable:L"db"
> +  ## SOMETIMES_CONSUMES   ## Variable:L"dbx"
> +  ## SOMETIMES_CONSUMES   ## Variable:L"dbt"
> +  gEfiImageSecurityDatabaseGuid
> +
> +  gVarCheckPolicyLibMmiHandlerGuid
> +  gEfiEndOfDxeEventGroupGuid
> +
> +[Depex]
> +  gEfiMmCommunication2ProtocolGuid
> +
> +[UserExtensions.TianoCore."ExtraFiles"]
> +  VariableSmmRuntimeDxeExtra.uni
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableStandalon
> eMm.inf
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableStandalon
> eMm.inf
> new file mode 100644
> index 000000000000..fb5a6c947890
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableStandalon
> eMm.inf
> @@ -0,0 +1,143 @@
> +## @file
> +#  Provides SMM variable service.
> +#
> +#  This module installs SMM variable protocol into SMM protocol database,
> +#  which can be used by SMM driver, and installs SMM variable protocol
> +#  into BS protocol database, which can be used to notify the SMM Runtime
> +#  Dxe driver that the SMM variable service is ready.
> +#  This module should be used with SMM Runtime DXE module together. The
> +#  SMM Runtime DXE module would install variable arch protocol and variable
> +#  write arch protocol based on SMM variable module.
> +#
> +#  Caution: This module requires additional review when modified.
> +#  This driver will have external input - variable data and communicate buffer in
> SMM mode.
> +#  This external input must be validated carefully to avoid security issues such
> as
> +#  buffer overflow or integer overflow.
> +#    The whole SMM authentication variable design relies on the integrity of
> flash part and SMM.
> +#  which is assumed to be protected by platform.  All variable code and
> metadata in flash/SMM Memory
> +#  may not be modified without authorization. If platform fails to protect these
> resources,
> +#  the authentication service provided in this driver will be broken, and the
> behavior is undefined.
> +#
> +# Copyright (c) 2010 - 2022, Intel Corporation. All rights reserved.<BR>
> +# Copyright (c) 2018, Linaro, Ltd. All rights reserved.<BR>
> +# Copyright (c) Microsoft Corporation.
> +# SPDX-License-Identifier: BSD-2-Clause-Patent
> +#
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 0x0001001B
> +  BASE_NAME                      = VariableStandaloneMm
> +  FILE_GUID                      = 417E6192-7678-4A75-B638-305A86D82936
> +  MODULE_TYPE                    = MM_STANDALONE
> +  VERSION_STRING                 = 1.0
> +  PI_SPECIFICATION_VERSION       = 0x00010032
> +  ENTRY_POINT                    = VariableServiceInitialize
> +
> +#
> +# The following information is for reference only and not required by the build
> tools.
> +#
> +#  VALID_ARCHITECTURES           = IA32 X64 ARM AARCH64
> +#
> +
> +
> +[Sources]
> +  Reclaim.c
> +  Variable.c
> +  VariableSmm.c
> +  VariableStandaloneMm.c
> +  VariableNonVolatile.c
> +  VariableNonVolatile.h
> +  VariableParsing.c
> +  VariableParsing.h
> +  VariableRuntimeCache.c
> +  VariableRuntimeCache.h
> +  VarCheck.c
> +  Variable.h
> +  PrivilegePolymorphic.h
> +  VariableExLib.c
> +  TcgMorLockSmm.c
> +  SpeculationBarrierSmm.c
> +  VariableLockRequestToLock.c
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +  MdeModulePkg/MdeModulePkg.dec
> +  StandaloneMmPkg/StandaloneMmPkg.dec
> +
> +[LibraryClasses]
> +  AuthVariableLib
> +  BaseLib
> +  BaseMemoryLib
> +  DebugLib
> +  HobLib
> +  MemoryAllocationLib
> +  MmServicesTableLib
> +  SafeIntLib
> +  StandaloneMmDriverEntryPoint
> +  SynchronizationLib
> +  VarCheckLib
> +  VariableFlashInfoLib
> +  VariablePolicyLib
> +  VariablePolicyHelperLib
> +  ProtectedVariableLib
> +
> +[Protocols]
> +  gEfiSmmFirmwareVolumeBlockProtocolGuid        ## CONSUMES
> +  ## CONSUMES
> +  ## NOTIFY
> +  gEfiSmmFaultTolerantWriteProtocolGuid
> +  ## PRODUCES
> +  ## UNDEFINED # SmiHandlerRegister
> +  gEfiSmmVariableProtocolGuid
> +  gEfiMmEndOfDxeProtocolGuid                   ## NOTIFY
> +  gEdkiiSmmVarCheckProtocolGuid                ## PRODUCES
> +
> +[Guids]
> +  ## SOMETIMES_CONSUMES   ## GUID # Signature of Variable store header
> +  ## SOMETIMES_PRODUCES   ## GUID # Signature of Variable store header
> +  ## SOMETIMES_CONSUMES   ## HOB
> +  ## SOMETIMES_PRODUCES   ## SystemTable
> +  gEfiAuthenticatedVariableGuid
> +
> +  ## SOMETIMES_CONSUMES   ## GUID # Signature of Variable store header
> +  ## SOMETIMES_PRODUCES   ## GUID # Signature of Variable store header
> +  ## SOMETIMES_CONSUMES   ## HOB
> +  ## SOMETIMES_PRODUCES   ## SystemTable
> +  gEfiVariableGuid
> +
> +  ## SOMETIMES_CONSUMES   ## Variable:L"PlatformLang"
> +  ## SOMETIMES_PRODUCES   ## Variable:L"PlatformLang"
> +  ## SOMETIMES_CONSUMES   ## Variable:L"Lang"
> +  ## SOMETIMES_PRODUCES   ## Variable:L"Lang"
> +  gEfiGlobalVariableGuid
> +
> +  gEfiMemoryOverwriteControlDataGuid            ## SOMETIMES_CONSUMES   ##
> Variable:L"MemoryOverwriteRequestControl"
> +  gEfiMemoryOverwriteRequestControlLockGuid     ## SOMETIMES_PRODUCES
> ## Variable:L"MemoryOverwriteRequestControlLock"
> +
> +  gEfiSystemNvDataFvGuid                        ## CONSUMES             ## GUID
> +  gEdkiiFaultTolerantWriteGuid                  ## SOMETIMES_CONSUMES   ## HOB
> +
> +  ## SOMETIMES_CONSUMES   ## Variable:L"VarErrorFlag"
> +  ## SOMETIMES_PRODUCES   ## Variable:L"VarErrorFlag"
> +  gEdkiiVarErrorFlagGuid
> +
> +[Pcd]
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdMaxVariableSize                  ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdMaxAuthVariableSize              ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdMaxVolatileVariableSize          ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdMaxHardwareErrorVariableSize     ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdVariableStoreSize                ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdHwErrStorageSize                 ##
> CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdMaxUserNvVariableSpaceSize
> ## CONSUMES
> +
> gEfiMdeModulePkgTokenSpaceGuid.PcdBoottimeReservedNvVariableSpaceSize
> ## CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdReclaimVariableSpaceAtEndOfDxe
> ## CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdEmuVariableNvModeEnable          ##
> SOMETIMES_CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdEmuVariableNvStoreReserved       ##
> SOMETIMES_CONSUMES
> +
> +[FeaturePcd]
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdVariableCollectStatistics        ##
> CONSUMES  # statistic the information of variable.
> +  gEfiMdePkgTokenSpaceGuid.PcdUefiVariableDefaultLangDeprecate       ##
> CONSUMES  # Auto update PlatformLang/Lang
> +
> +[Depex]
> +  TRUE
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/PrivilegePolymorp
> hic.h
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/PrivilegePolymorp
> hic.h
> new file mode 100644
> index 000000000000..7f14515b694f
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/PrivilegePolymorp
> hic.h
> @@ -0,0 +1,158 @@
> +/** @file
> +  Polymorphic functions that are called from both the privileged driver (i.e.,
> +  the DXE_SMM variable module) and the non-privileged drivers (i.e., one or
> +  both of the DXE_RUNTIME variable modules).
> +
> +  Each of these functions has two implementations, appropriate for privileged
> +  vs. non-privileged driver code.
> +
> +  Copyright (c) 2017, Red Hat, Inc.<BR>
> +  Copyright (c) 2010 - 2022, Intel Corporation. All rights reserved.<BR>
> +
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +**/
> +
> +#ifndef PRIVILEGE_POLYMORPHIC_H_
> +#define PRIVILEGE_POLYMORPHIC_H_
> +
> +#include <Uefi/UefiBaseType.h>
> +
> +/**
> +  SecureBoot Hook for auth variable update.
> +
> +  @param[in] VariableName                 Name of Variable to be found.
> +  @param[in] VendorGuid                   Variable vendor GUID.
> +**/
> +VOID
> +EFIAPI
> +SecureBootHook (
> +  IN CHAR16    *VariableName,
> +  IN EFI_GUID  *VendorGuid
> +  );
> +
> +/**
> +  Initialization for MOR Control Lock.
> +
> +  @retval EFI_SUCCESS     MorLock initialization success.
> +  @return Others          Some error occurs.
> +**/
> +EFI_STATUS
> +MorLockInit (
> +  VOID
> +  );
> +
> +/**
> +  Delayed initialization for MOR Control Lock at EndOfDxe.
> +
> +  This function performs any operations queued by MorLockInit().
> +**/
> +VOID
> +MorLockInitAtEndOfDxe (
> +  VOID
> +  );
> +
> +/**
> +  This service is an MOR/MorLock checker handler for the SetVariable().
> +
> +  @param[in]  VariableName the name of the vendor's variable, as a
> +                           Null-Terminated Unicode String
> +  @param[in]  VendorGuid   Unify identifier for vendor.
> +  @param[in]  Attributes   Attributes bitmask to set for the variable.
> +  @param[in]  DataSize     The size in bytes of Data-Buffer.
> +  @param[in]  Data         Point to the content of the variable.
> +
> +  @retval  EFI_SUCCESS            The MOR/MorLock check pass, and Variable
> +                                  driver can store the variable data.
> +  @retval  EFI_INVALID_PARAMETER  The MOR/MorLock data or data size or
> +                                  attributes is not allowed for MOR variable.
> +  @retval  EFI_ACCESS_DENIED      The MOR/MorLock is locked.
> +  @retval  EFI_ALREADY_STARTED    The MorLock variable is handled inside this
> +                                  function. Variable driver can just return
> +                                  EFI_SUCCESS.
> +**/
> +EFI_STATUS
> +SetVariableCheckHandlerMor (
> +  IN CHAR16    *VariableName,
> +  IN EFI_GUID  *VendorGuid,
> +  IN UINT32    Attributes,
> +  IN UINTN     DataSize,
> +  IN VOID      *Data
> +  );
> +
> +/**
> +  This service is consumed by the variable modules to place a barrier to stop
> +  speculative execution.
> +
> +  Ensures that no later instruction will execute speculatively, until all prior
> +  instructions have completed.
> +
> +**/
> +VOID
> +VariableSpeculationBarrier (
> +  VOID
> +  );
> +
> +/**
> +  Notify the system that the SMM variable driver is ready.
> +**/
> +VOID
> +VariableNotifySmmReady (
> +  VOID
> +  );
> +
> +/**
> +  Notify the system that the SMM variable write driver is ready.
> +**/
> +VOID
> +VariableNotifySmmWriteReady (
> +  VOID
> +  );
> +
> +/**
> +  Variable Driver main entry point. The Variable driver places the 4 EFI
> +  runtime services in the EFI System Table and installs arch protocols
> +  for variable read and write services being available. It also registers
> +  a notification function for an EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE
> event.
> +
> +  @retval EFI_SUCCESS       Variable service successfully initialized.
> +**/
> +EFI_STATUS
> +EFIAPI
> +MmVariableServiceInitialize (
> +  VOID
> +  );
> +
> +/**
> +  This function checks if the buffer is valid per processor architecture and
> +  does not overlap with SMRAM.
> +
> +  @param Buffer The buffer start address to be checked.
> +  @param Length The buffer length to be checked.
> +
> +  @retval TRUE  This buffer is valid per processor architecture and does not
> +                overlap with SMRAM.
> +  @retval FALSE This buffer is not valid per processor architecture or overlaps
> +                with SMRAM.
> +**/
> +BOOLEAN
> +VariableSmmIsBufferOutsideSmmValid (
> +  IN EFI_PHYSICAL_ADDRESS  Buffer,
> +  IN UINT64                Length
> +  );
> +
> +/**
> +  Whether the TCG or TCG2 protocols are installed in the UEFI protocol
> database.
> +  This information is used by the MorLock code to infer whether an existing
> +  MOR variable is legitimate or not.
> +
> +  @retval TRUE  Either the TCG or TCG2 protocol is installed in the UEFI
> +                protocol database
> +  @retval FALSE Neither the TCG nor the TCG2 protocol is installed in the UEFI
> +                protocol database
> +**/
> +BOOLEAN
> +VariableHaveTcgProtocols (
> +  VOID
> +  );
> +
> +#endif
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/Variable.h
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/Variable.h
> new file mode 100644
> index 000000000000..c679e524043f
> --- /dev/null
> +++ b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/Variable.h
> @@ -0,0 +1,948 @@
> +/** @file
> +  The internal header file includes the common header files, defines
> +  internal structure and functions used by Variable modules.
> +
> +Copyright (c) 2006 - 2022, Intel Corporation. All rights reserved.<BR>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#ifndef VARIABLE_H_
> +#define VARIABLE_H_
> +
> +#include <PiDxe.h>
> +#include <Protocol/VariableWrite.h>
> +#include <Protocol/FaultTolerantWrite.h>
> +#include <Protocol/FirmwareVolumeBlock.h>
> +#include <Protocol/Variable.h>
> +#include <Protocol/VariableLock.h>
> +#include <Protocol/VarCheck.h>
> +#include <Library/PcdLib.h>
> +#include <Library/HobLib.h>
> +#include <Library/UefiDriverEntryPoint.h>
> +#include <Library/DxeServicesTableLib.h>
> +#include <Library/UefiRuntimeLib.h>
> +#include <Library/DebugLib.h>
> +#include <Library/BaseMemoryLib.h>
> +#include <Library/UefiBootServicesTableLib.h>
> +#include <Library/UefiLib.h>
> +#include <Library/BaseLib.h>
> +#include <Library/SynchronizationLib.h>
> +#include <Library/MemoryAllocationLib.h>
> +#include <Library/AuthVariableLib.h>
> +#include <Library/VarCheckLib.h>
> +#include <Library/VariableFlashInfoLib.h>
> +#include <Library/SafeIntLib.h>
> +#include <Library/ProtectedVariableLib.h>
> +#include <Guid/GlobalVariable.h>
> +#include <Guid/EventGroup.h>
> +#include <Guid/VariableFormat.h>
> +#include <Guid/SystemNvDataGuid.h>
> +#include <Guid/FaultTolerantWrite.h>
> +#include <Guid/VarErrorFlag.h>
> +
> +#include "PrivilegePolymorphic.h"
> +
> +#define EFI_VARIABLE_ATTRIBUTES_MASK  (EFI_VARIABLE_NON_VOLATILE |\
> +                                      EFI_VARIABLE_BOOTSERVICE_ACCESS | \
> +                                      EFI_VARIABLE_RUNTIME_ACCESS | \
> +                                      EFI_VARIABLE_HARDWARE_ERROR_RECORD | \
> +
> EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS | \
> +                                      EFI_VARIABLE_APPEND_WRITE)
> +
> +///
> +/// The size of a 3 character ISO639 language code.
> +///
> +#define ISO_639_2_ENTRY_SIZE  3
> +
> +typedef enum {
> +  VariableStoreTypeVolatile,
> +  VariableStoreTypeHob,
> +  VariableStoreTypeNv,
> +  VariableStoreTypeMax
> +} VARIABLE_STORE_TYPE;
> +
> +typedef struct {
> +  UINT32                   PendingUpdateOffset;
> +  UINT32                   PendingUpdateLength;
> +  VARIABLE_STORE_HEADER    *Store;
> +} VARIABLE_RUNTIME_CACHE;
> +
> +typedef struct {
> +  BOOLEAN                   *ReadLock;
> +  BOOLEAN                   *PendingUpdate;
> +  BOOLEAN                   *HobFlushComplete;
> +  VARIABLE_RUNTIME_CACHE    VariableRuntimeHobCache;
> +  VARIABLE_RUNTIME_CACHE    VariableRuntimeNvCache;
> +  VARIABLE_RUNTIME_CACHE    VariableRuntimeVolatileCache;
> +} VARIABLE_RUNTIME_CACHE_CONTEXT;
> +
> +typedef struct {
> +  VARIABLE_HEADER    *CurrPtr;
> +  //
> +  // If both ADDED and IN_DELETED_TRANSITION variable are present,
> +  // InDeletedTransitionPtr will point to the IN_DELETED_TRANSITION one.
> +  // Otherwise, CurrPtr will point to the ADDED or IN_DELETED_TRANSITION
> one,
> +  // and InDeletedTransitionPtr will be NULL at the same time.
> +  //
> +  VARIABLE_HEADER    *InDeletedTransitionPtr;
> +  VARIABLE_HEADER    *EndPtr;
> +  VARIABLE_HEADER    *StartPtr;
> +  BOOLEAN            Volatile;
> +} VARIABLE_POINTER_TRACK;
> +
> +typedef struct {
> +  EFI_PHYSICAL_ADDRESS              HobVariableBase;
> +  EFI_PHYSICAL_ADDRESS              VolatileVariableBase;
> +  EFI_PHYSICAL_ADDRESS              NonVolatileVariableBase;
> +  VARIABLE_RUNTIME_CACHE_CONTEXT    VariableRuntimeCacheContext;
> +  EFI_LOCK                          VariableServicesLock;
> +  UINT32                            ReentrantState;
> +  BOOLEAN                           AuthFormat;
> +  BOOLEAN                           AuthSupport;
> +  BOOLEAN                           EmuNvMode;
> +} VARIABLE_GLOBAL;
> +
> +typedef struct {
> +  VARIABLE_GLOBAL                       VariableGlobal;
> +  UINTN                                 VolatileLastVariableOffset;
> +  UINTN                                 NonVolatileLastVariableOffset;
> +  UINTN                                 CommonVariableSpace;
> +  UINTN                                 CommonMaxUserVariableSpace;
> +  UINTN                                 CommonRuntimeVariableSpace;
> +  UINTN                                 CommonVariableTotalSize;
> +  UINTN                                 CommonUserVariableTotalSize;
> +  UINTN                                 HwErrVariableTotalSize;
> +  UINTN                                 MaxVariableSize;
> +  UINTN                                 MaxAuthVariableSize;
> +  UINTN                                 MaxVolatileVariableSize;
> +  UINTN                                 ScratchBufferSize;
> +  CHAR8                                 *PlatformLangCodes;
> +  CHAR8                                 *LangCodes;
> +  CHAR8                                 *PlatformLang;
> +  CHAR8                                 Lang[ISO_639_2_ENTRY_SIZE + 1];
> +  EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL    *FvbInstance;
> +} VARIABLE_MODULE_GLOBAL;
> +
> +/**
> +  Flush the HOB variable to flash.
> +
> +  @param[in] VariableName       Name of variable has been updated or deleted.
> +  @param[in] VendorGuid         Guid of variable has been updated or deleted.
> +
> +**/
> +VOID
> +FlushHobVariableToFlash (
> +  IN CHAR16    *VariableName,
> +  IN EFI_GUID  *VendorGuid
> +  );
> +
> +/**
> +  Writes a buffer to variable storage space, in the working block.
> +
> +  This function writes a buffer to variable storage space into a firmware
> +  volume block device. The destination is specified by the parameter
> +  VariableBase. Fault Tolerant Write protocol is used for writing.
> +
> +  @param  VariableBase   Base address of the variable to write.
> +  @param  VariableBuffer Point to the variable data buffer.
> +
> +  @retval EFI_SUCCESS    The function completed successfully.
> +  @retval EFI_NOT_FOUND  Fail to locate Fault Tolerant Write protocol.
> +  @retval EFI_ABORTED    The function could not complete successfully.
> +
> +**/
> +EFI_STATUS
> +FtwVariableSpace (
> +  IN EFI_PHYSICAL_ADDRESS   VariableBase,
> +  IN VARIABLE_STORE_HEADER  *VariableBuffer
> +  );
> +
> +/**
> +  Finds variable in storage blocks of volatile and non-volatile storage areas.
> +
> +  This code finds variable in storage blocks of volatile and non-volatile storage
> areas.
> +  If VariableName is an empty string, then we just return the first
> +  qualified variable without comparing VariableName and VendorGuid.
> +  If IgnoreRtCheck is TRUE, then we ignore the
> EFI_VARIABLE_RUNTIME_ACCESS attribute check
> +  at runtime when searching existing variable, only VariableName and
> VendorGuid are compared.
> +  Otherwise, variables without EFI_VARIABLE_RUNTIME_ACCESS are not visible
> at runtime.
> +
> +  @param[in]   VariableName           Name of the variable to be found.
> +  @param[in]   VendorGuid             Vendor GUID to be found.
> +  @param[out]  PtrTrack               VARIABLE_POINTER_TRACK structure for
> output,
> +                                      including the range searched and the target position.
> +  @param[in]   Global                 Pointer to VARIABLE_GLOBAL structure,
> including
> +                                      base of volatile variable storage area, base of
> +                                      NV variable storage area, and a lock.
> +  @param[in]   IgnoreRtCheck          Ignore EFI_VARIABLE_RUNTIME_ACCESS
> attribute
> +                                      check at runtime when searching variable.
> +
> +  @retval EFI_INVALID_PARAMETER       If VariableName is not an empty string,
> while
> +                                      VendorGuid is NULL.
> +  @retval EFI_SUCCESS                 Variable successfully found.
> +  @retval EFI_NOT_FOUND               Variable not found
> +
> +**/
> +EFI_STATUS
> +FindVariable (
> +  IN  CHAR16                  *VariableName,
> +  IN  EFI_GUID                *VendorGuid,
> +  OUT VARIABLE_POINTER_TRACK  *PtrTrack,
> +  IN  VARIABLE_GLOBAL         *Global,
> +  IN  BOOLEAN                 IgnoreRtCheck
> +  );
> +
> +/**
> +  This function is to check if the remaining variable space is enough to set
> +  all Variables from argument list successfully. The purpose of the check
> +  is to keep the consistency of the Variables to be in variable storage.
> +
> +  Note: Variables are assumed to be in same storage.
> +  The set sequence of Variables will be same with the sequence of VariableEntry
> from argument list,
> +  so follow the argument sequence to check the Variables.
> +
> +  @param[in] Attributes         Variable attributes for Variable entries.
> +  @param[in] Marker             VA_LIST style variable argument list.
> +                                The variable argument list with type
> VARIABLE_ENTRY_CONSISTENCY *.
> +                                A NULL terminates the list. The VariableSize of
> +                                VARIABLE_ENTRY_CONSISTENCY is the variable data size as
> input.
> +                                It will be changed to variable total size as output.
> +
> +  @retval TRUE                  Have enough variable space to set the Variables
> successfully.
> +  @retval FALSE                 No enough variable space to set the Variables
> successfully.
> +
> +**/
> +BOOLEAN
> +EFIAPI
> +CheckRemainingSpaceForConsistencyInternal (
> +  IN UINT32   Attributes,
> +  IN VA_LIST  Marker
> +  );
> +
> +/**
> +  Update the variable region with Variable information. If
> EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS is set,
> +  index of associated public key is needed.
> +
> +  @param[in] VariableName       Name of variable.
> +  @param[in] VendorGuid         Guid of variable.
> +  @param[in] Data               Variable data.
> +  @param[in] DataSize           Size of data. 0 means delete.
> +  @param[in] Attributes         Attributes of the variable.
> +  @param[in] KeyIndex           Index of associated public key.
> +  @param[in] MonotonicCount     Value of associated monotonic count.
> +  @param[in, out] Variable      The variable information that is used to keep
> track of variable usage.
> +
> +  @param[in] TimeStamp          Value of associated TimeStamp.
> +
> +  @retval EFI_SUCCESS           The update operation is success.
> +  @retval EFI_OUT_OF_RESOURCES  Variable region is full, cannot write other
> data into this region.
> +
> +**/
> +EFI_STATUS
> +UpdateVariable (
> +  IN      CHAR16                  *VariableName,
> +  IN      EFI_GUID                *VendorGuid,
> +  IN      VOID                    *Data,
> +  IN      UINTN                   DataSize,
> +  IN      UINT32                  Attributes OPTIONAL,
> +  IN      UINT32                  KeyIndex  OPTIONAL,
> +  IN      UINT64                  MonotonicCount  OPTIONAL,
> +  IN OUT  VARIABLE_POINTER_TRACK  *Variable,
> +  IN      EFI_TIME                *TimeStamp  OPTIONAL
> +  );
> +
> +/**
> +  Return TRUE if ExitBootServices () has been called.
> +
> +  @retval TRUE If ExitBootServices () has been called.
> +**/
> +BOOLEAN
> +AtRuntime (
> +  VOID
> +  );
> +
> +/**
> +  Initializes a basic mutual exclusion lock.
> +
> +  This function initializes a basic mutual exclusion lock to the released state
> +  and returns the lock.  Each lock provides mutual exclusion access at its task
> +  priority level.  Since there is no preemption or multiprocessor support in EFI,
> +  acquiring the lock only consists of raising to the locks TPL.
> +  If Lock is NULL, then ASSERT().
> +  If Priority is not a valid TPL value, then ASSERT().
> +
> +  @param  Lock       A pointer to the lock data structure to initialize.
> +  @param  Priority   EFI TPL is associated with the lock.
> +
> +  @return The lock.
> +
> +**/
> +EFI_LOCK *
> +InitializeLock (
> +  IN OUT EFI_LOCK  *Lock,
> +  IN EFI_TPL       Priority
> +  );
> +
> +/**
> +  Acquires lock only at boot time. Simply returns at runtime.
> +
> +  This is a temperary function that will be removed when
> +  EfiAcquireLock() in UefiLib can handle the call in UEFI
> +  Runtimer driver in RT phase.
> +  It calls EfiAcquireLock() at boot time, and simply returns
> +  at runtime.
> +
> +  @param  Lock         A pointer to the lock to acquire.
> +
> +**/
> +VOID
> +AcquireLockOnlyAtBootTime (
> +  IN EFI_LOCK  *Lock
> +  );
> +
> +/**
> +  Releases lock only at boot time. Simply returns at runtime.
> +
> +  This is a temperary function which will be removed when
> +  EfiReleaseLock() in UefiLib can handle the call in UEFI
> +  Runtimer driver in RT phase.
> +  It calls EfiReleaseLock() at boot time and simply returns
> +  at runtime.
> +
> +  @param  Lock         A pointer to the lock to release.
> +
> +**/
> +VOID
> +ReleaseLockOnlyAtBootTime (
> +  IN EFI_LOCK  *Lock
> +  );
> +
> +/**
> +  Retrieve the FVB protocol interface by HANDLE.
> +
> +  @param[in]  FvBlockHandle     The handle of FVB protocol that provides
> services for
> +                                reading, writing, and erasing the target block.
> +  @param[out] FvBlock           The interface of FVB protocol
> +
> +  @retval EFI_SUCCESS           The interface information for the specified
> protocol was returned.
> +  @retval EFI_UNSUPPORTED       The device does not support the FVB protocol.
> +  @retval EFI_INVALID_PARAMETER FvBlockHandle is not a valid EFI_HANDLE
> or FvBlock is NULL.
> +
> +**/
> +EFI_STATUS
> +GetFvbByHandle (
> +  IN  EFI_HANDLE                          FvBlockHandle,
> +  OUT EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  **FvBlock
> +  );
> +
> +/**
> +  Function returns an array of handles that support the FVB protocol
> +  in a buffer allocated from pool.
> +
> +  @param[out]  NumberHandles    The number of handles returned in Buffer.
> +  @param[out]  Buffer           A pointer to the buffer to return the requested
> +                                array of  handles that support FVB protocol.
> +
> +  @retval EFI_SUCCESS           The array of handles was returned in Buffer, and
> the number of
> +                                handles in Buffer was returned in NumberHandles.
> +  @retval EFI_NOT_FOUND         No FVB handle was found.
> +  @retval EFI_OUT_OF_RESOURCES  There is not enough pool memory to store
> the matching results.
> +  @retval EFI_INVALID_PARAMETER NumberHandles is NULL or Buffer is NULL.
> +
> +**/
> +EFI_STATUS
> +GetFvbCountAndBuffer (
> +  OUT UINTN       *NumberHandles,
> +  OUT EFI_HANDLE  **Buffer
> +  );
> +
> +/**
> +  Initializes variable store area for non-volatile and volatile variable.
> +
> +  @retval EFI_SUCCESS           Function successfully executed.
> +  @retval EFI_OUT_OF_RESOURCES  Fail to allocate enough memory resource.
> +
> +**/
> +EFI_STATUS
> +VariableCommonInitialize (
> +  VOID
> +  );
> +
> +/**
> +  This function reclaims variable storage if free size is below the threshold.
> +
> +**/
> +VOID
> +ReclaimForOS (
> +  VOID
> +  );
> +
> +/**
> +  Get maximum variable size, covering both non-volatile and volatile variables.
> +
> +  @return Maximum variable size.
> +
> +**/
> +UINTN
> +GetMaxVariableSize (
> +  VOID
> +  );
> +
> +/**
> +  Initializes variable write service.
> +
> +  @retval EFI_SUCCESS          Function successfully executed.
> +  @retval Others               Fail to initialize the variable service.
> +
> +**/
> +EFI_STATUS
> +VariableWriteServiceInitialize (
> +  VOID
> +  );
> +
> +/**
> +  Retrieve the SMM Fault Tolerent Write protocol interface.
> +
> +  @param[out] FtwProtocol       The interface of SMM Ftw protocol
> +
> +  @retval EFI_SUCCESS           The SMM SAR protocol instance was found and
> returned in SarProtocol.
> +  @retval EFI_NOT_FOUND         The SMM SAR protocol instance was not found.
> +  @retval EFI_INVALID_PARAMETER SarProtocol is NULL.
> +
> +**/
> +EFI_STATUS
> +GetFtwProtocol (
> +  OUT VOID  **FtwProtocol
> +  );
> +
> +/**
> +  Get the proper fvb handle and/or fvb protocol by the given Flash address.
> +
> +  @param[in] Address        The Flash address.
> +  @param[out] FvbHandle     In output, if it is not NULL, it points to the proper
> FVB handle.
> +  @param[out] FvbProtocol   In output, if it is not NULL, it points to the proper
> FVB protocol.
> +
> +**/
> +EFI_STATUS
> +GetFvbInfoByAddress (
> +  IN  EFI_PHYSICAL_ADDRESS                Address,
> +  OUT EFI_HANDLE                          *FvbHandle OPTIONAL,
> +  OUT EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  **FvbProtocol OPTIONAL
> +  );
> +
> +/**
> +
> +  This code finds variable in storage blocks (Volatile or Non-Volatile).
> +
> +  Caution: This function may receive untrusted input.
> +  This function may be invoked in SMM mode, and datasize and data are
> external input.
> +  This function will do basic validation, before parse the data.
> +
> +  @param VariableName               Name of Variable to be found.
> +  @param VendorGuid                 Variable vendor GUID.
> +  @param Attributes                 Attribute value of the variable found.
> +  @param DataSize                   Size of Data found. If size is less than the
> +                                    data, this value contains the required size.
> +  @param Data                       The buffer to return the contents of the variable.
> May be NULL
> +                                    with a zero DataSize in order to determine the size buffer
> needed.
> +
> +  @return EFI_INVALID_PARAMETER     Invalid parameter.
> +  @return EFI_SUCCESS               Find the specified variable.
> +  @return EFI_NOT_FOUND             Not found.
> +  @return EFI_BUFFER_TO_SMALL       DataSize is too small for the result.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableServiceGetVariable (
> +  IN      CHAR16    *VariableName,
> +  IN      EFI_GUID  *VendorGuid,
> +  OUT     UINT32    *Attributes OPTIONAL,
> +  IN OUT  UINTN     *DataSize,
> +  OUT     VOID      *Data OPTIONAL
> +  );
> +
> +/**
> +
> +  This code Finds the Next available variable.
> +
> +  Caution: This function may receive untrusted input.
> +  This function may be invoked in SMM mode. This function will do basic
> validation, before parse the data.
> +
> +  @param VariableNameSize           The size of the VariableName buffer. The
> size must be large
> +                                    enough to fit input string supplied in VariableName buffer.
> +  @param VariableName               Pointer to variable name.
> +  @param VendorGuid                 Variable Vendor Guid.
> +
> +  @retval EFI_SUCCESS               The function completed successfully.
> +  @retval EFI_NOT_FOUND             The next variable was not found.
> +  @retval EFI_BUFFER_TOO_SMALL      The VariableNameSize is too small for
> the result.
> +                                    VariableNameSize has been updated with the size needed
> to complete the request.
> +  @retval EFI_INVALID_PARAMETER     VariableNameSize is NULL.
> +  @retval EFI_INVALID_PARAMETER     VariableName is NULL.
> +  @retval EFI_INVALID_PARAMETER     VendorGuid is NULL.
> +  @retval EFI_INVALID_PARAMETER     The input values of VariableName and
> VendorGuid are not a name and
> +                                    GUID of an existing variable.
> +  @retval EFI_INVALID_PARAMETER     Null-terminator is not found in the first
> VariableNameSize bytes of
> +                                    the input VariableName buffer.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableServiceGetNextVariableName (
> +  IN OUT  UINTN     *VariableNameSize,
> +  IN OUT  CHAR16    *VariableName,
> +  IN OUT  EFI_GUID  *VendorGuid
> +  );
> +
> +/**
> +
> +  This code sets variable in storage blocks (Volatile or Non-Volatile).
> +
> +  Caution: This function may receive untrusted input.
> +  This function may be invoked in SMM mode, and datasize and data are
> external input.
> +  This function will do basic validation, before parse the data.
> +  This function will parse the authentication carefully to avoid security issues,
> like
> +  buffer overflow, integer overflow.
> +  This function will check attribute carefully to avoid authentication bypass.
> +
> +  @param VariableName                     Name of Variable to be found.
> +  @param VendorGuid                       Variable vendor GUID.
> +  @param Attributes                       Attribute value of the variable found
> +  @param DataSize                         Size of Data found. If size is less than the
> +                                          data, this value contains the required size.
> +  @param Data                             Data pointer.
> +
> +  @return EFI_INVALID_PARAMETER           Invalid parameter.
> +  @return EFI_SUCCESS                     Set successfully.
> +  @return EFI_OUT_OF_RESOURCES            Resource not enough to set variable.
> +  @return EFI_NOT_FOUND                   Not found.
> +  @return EFI_WRITE_PROTECTED             Variable is read-only.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableServiceSetVariable (
> +  IN CHAR16    *VariableName,
> +  IN EFI_GUID  *VendorGuid,
> +  IN UINT32    Attributes,
> +  IN UINTN     DataSize,
> +  IN VOID      *Data
> +  );
> +
> +/**
> +
> +  This code returns information about the EFI variables.
> +
> +  Caution: This function may receive untrusted input.
> +  This function may be invoked in SMM mode. This function will do basic
> validation, before parse the data.
> +
> +  @param Attributes                     Attributes bitmask to specify the type of
> variables
> +                                        on which to return information.
> +  @param MaximumVariableStorageSize     Pointer to the maximum size of the
> storage space available
> +                                        for the EFI variables associated with the attributes
> specified.
> +  @param RemainingVariableStorageSize   Pointer to the remaining size of the
> storage space available
> +                                        for EFI variables associated with the attributes specified.
> +  @param MaximumVariableSize            Pointer to the maximum size of an
> individual EFI variables
> +                                        associated with the attributes specified.
> +
> +  @return EFI_SUCCESS                   Query successfully.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableServiceQueryVariableInfoInternal (
> +  IN  UINT32  Attributes,
> +  OUT UINT64  *MaximumVariableStorageSize,
> +  OUT UINT64  *RemainingVariableStorageSize,
> +  OUT UINT64  *MaximumVariableSize
> +  );
> +
> +/**
> +
> +  This code returns information about the EFI variables.
> +
> +  Caution: This function may receive untrusted input.
> +  This function may be invoked in SMM mode. This function will do basic
> validation, before parse the data.
> +
> +  @param Attributes                     Attributes bitmask to specify the type of
> variables
> +                                        on which to return information.
> +  @param MaximumVariableStorageSize     Pointer to the maximum size of the
> storage space available
> +                                        for the EFI variables associated with the attributes
> specified.
> +  @param RemainingVariableStorageSize   Pointer to the remaining size of the
> storage space available
> +                                        for EFI variables associated with the attributes specified.
> +  @param MaximumVariableSize            Pointer to the maximum size of an
> individual EFI variables
> +                                        associated with the attributes specified.
> +
> +  @return EFI_INVALID_PARAMETER         An invalid combination of attribute
> bits was supplied.
> +  @return EFI_SUCCESS                   Query successfully.
> +  @return EFI_UNSUPPORTED               The attribute is not supported on this
> platform.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableServiceQueryVariableInfo (
> +  IN  UINT32  Attributes,
> +  OUT UINT64  *MaximumVariableStorageSize,
> +  OUT UINT64  *RemainingVariableStorageSize,
> +  OUT UINT64  *MaximumVariableSize
> +  );
> +
> +/**
> +  Mark a variable that will become read-only after leaving the DXE phase of
> execution.
> +
> +  @param[in] This          The VARIABLE_LOCK_PROTOCOL instance.
> +  @param[in] VariableName  A pointer to the variable name that will be made
> read-only subsequently.
> +  @param[in] VendorGuid    A pointer to the vendor GUID that will be made
> read-only subsequently.
> +
> +  @retval EFI_SUCCESS           The variable specified by the VariableName and
> the VendorGuid was marked
> +                                as pending to be read-only.
> +  @retval EFI_INVALID_PARAMETER VariableName or VendorGuid is NULL.
> +                                Or VariableName is an empty string.
> +  @retval EFI_ACCESS_DENIED     EFI_END_OF_DXE_EVENT_GROUP_GUID or
> EFI_EVENT_GROUP_READY_TO_BOOT has
> +                                already been signaled.
> +  @retval EFI_OUT_OF_RESOURCES  There is not enough resource to hold the
> lock request.
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableLockRequestToLock (
> +  IN CONST EDKII_VARIABLE_LOCK_PROTOCOL  *This,
> +  IN       CHAR16                        *VariableName,
> +  IN       EFI_GUID                      *VendorGuid
> +  );
> +
> +/**
> +  Register SetVariable check handler.
> +
> +  @param[in] Handler            Pointer to check handler.
> +
> +  @retval EFI_SUCCESS           The SetVariable check handler was registered
> successfully.
> +  @retval EFI_INVALID_PARAMETER Handler is NULL.
> +  @retval EFI_ACCESS_DENIED     EFI_END_OF_DXE_EVENT_GROUP_GUID or
> EFI_EVENT_GROUP_READY_TO_BOOT has
> +                                already been signaled.
> +  @retval EFI_OUT_OF_RESOURCES  There is not enough resource for the
> SetVariable check handler register request.
> +  @retval EFI_UNSUPPORTED       This interface is not implemented.
> +                                For example, it is unsupported in VarCheck protocol if both
> VarCheck and SmmVarCheck protocols are present.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VarCheckRegisterSetVariableCheckHandler (
> +  IN VAR_CHECK_SET_VARIABLE_CHECK_HANDLER  Handler
> +  );
> +
> +/**
> +  Variable property set.
> +
> +  @param[in] Name               Pointer to the variable name.
> +  @param[in] Guid               Pointer to the vendor GUID.
> +  @param[in] VariableProperty   Pointer to the input variable property.
> +
> +  @retval EFI_SUCCESS           The property of variable specified by the Name
> and Guid was set successfully.
> +  @retval EFI_INVALID_PARAMETER Name, Guid or VariableProperty is NULL,
> or Name is an empty string,
> +                                or the fields of VariableProperty are not valid.
> +  @retval EFI_ACCESS_DENIED     EFI_END_OF_DXE_EVENT_GROUP_GUID or
> EFI_EVENT_GROUP_READY_TO_BOOT has
> +                                already been signaled.
> +  @retval EFI_OUT_OF_RESOURCES  There is not enough resource for the
> variable property set request.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VarCheckVariablePropertySet (
> +  IN CHAR16                       *Name,
> +  IN EFI_GUID                     *Guid,
> +  IN VAR_CHECK_VARIABLE_PROPERTY  *VariableProperty
> +  );
> +
> +/**
> +  Variable property get.
> +
> +  @param[in]  Name              Pointer to the variable name.
> +  @param[in]  Guid              Pointer to the vendor GUID.
> +  @param[out] VariableProperty  Pointer to the output variable property.
> +
> +  @retval EFI_SUCCESS           The property of variable specified by the Name
> and Guid was got successfully.
> +  @retval EFI_INVALID_PARAMETER Name, Guid or VariableProperty is NULL,
> or Name is an empty string.
> +  @retval EFI_NOT_FOUND         The property of variable specified by the Name
> and Guid was not found.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VarCheckVariablePropertyGet (
> +  IN CHAR16                        *Name,
> +  IN EFI_GUID                      *Guid,
> +  OUT VAR_CHECK_VARIABLE_PROPERTY  *VariableProperty
> +  );
> +
> +/**
> +  Initialize variable quota.
> +
> +**/
> +VOID
> +InitializeVariableQuota (
> +  VOID
> +  );
> +
> +extern VARIABLE_MODULE_GLOBAL      *mVariableModuleGlobal;
> +extern EFI_FIRMWARE_VOLUME_HEADER  *mNvFvHeaderCache;
> +extern VARIABLE_STORE_HEADER       *mNvVariableCache;
> +extern VARIABLE_INFO_ENTRY         *gVariableInfo;
> +extern BOOLEAN                     mEndOfDxe;
> +extern VAR_CHECK_REQUEST_SOURCE    mRequestSource;
> +
> +extern AUTH_VAR_LIB_CONTEXT_OUT  mAuthContextOut;
> +
> +/**
> +  Finds variable in storage blocks of volatile and non-volatile storage areas.
> +
> +  This code finds variable in storage blocks of volatile and non-volatile storage
> areas.
> +  If VariableName is an empty string, then we just return the first
> +  qualified variable without comparing VariableName and VendorGuid.
> +
> +  @param[in]  VariableName          Name of the variable to be found.
> +  @param[in]  VendorGuid            Variable vendor GUID to be found.
> +  @param[out] AuthVariableInfo      Pointer to AUTH_VARIABLE_INFO structure
> for
> +                                    output of the variable found.
> +
> +  @retval EFI_INVALID_PARAMETER     If VariableName is not an empty string,
> +                                    while VendorGuid is NULL.
> +  @retval EFI_SUCCESS               Variable successfully found.
> +  @retval EFI_NOT_FOUND             Variable not found
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableExLibFindVariable (
> +  IN  CHAR16              *VariableName,
> +  IN  EFI_GUID            *VendorGuid,
> +  OUT AUTH_VARIABLE_INFO  *AuthVariableInfo
> +  );
> +
> +/**
> +  Finds next variable in storage blocks of volatile and non-volatile storage areas.
> +
> +  This code finds next variable in storage blocks of volatile and non-volatile
> storage areas.
> +  If VariableName is an empty string, then we just return the first
> +  qualified variable without comparing VariableName and VendorGuid.
> +
> +  @param[in]  VariableName          Name of the variable to be found.
> +  @param[in]  VendorGuid            Variable vendor GUID to be found.
> +  @param[out] AuthVariableInfo      Pointer to AUTH_VARIABLE_INFO structure
> for
> +                                    output of the next variable.
> +
> +  @retval EFI_INVALID_PARAMETER     If VariableName is not an empty string,
> +                                    while VendorGuid is NULL.
> +  @retval EFI_SUCCESS               Variable successfully found.
> +  @retval EFI_NOT_FOUND             Variable not found
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableExLibFindNextVariable (
> +  IN  CHAR16              *VariableName,
> +  IN  EFI_GUID            *VendorGuid,
> +  OUT AUTH_VARIABLE_INFO  *AuthVariableInfo
> +  );
> +
> +/**
> +  Update the variable region with Variable information.
> +
> +  @param[in] AuthVariableInfo       Pointer AUTH_VARIABLE_INFO structure for
> +                                    input of the variable.
> +
> +  @retval EFI_SUCCESS               The update operation is success.
> +  @retval EFI_INVALID_PARAMETER     Invalid parameter.
> +  @retval EFI_WRITE_PROTECTED       Variable is write-protected.
> +  @retval EFI_OUT_OF_RESOURCES      There is not enough resource.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableExLibUpdateVariable (
> +  IN AUTH_VARIABLE_INFO  *AuthVariableInfo
> +  );
> +
> +/**
> +  Get scratch buffer.
> +
> +  @param[in, out] ScratchBufferSize Scratch buffer size. If input size is greater
> than
> +                                    the maximum supported buffer size, this value contains
> +                                    the maximum supported buffer size as output.
> +  @param[out]     ScratchBuffer     Pointer to scratch buffer address.
> +
> +  @retval EFI_SUCCESS       Get scratch buffer successfully.
> +  @retval EFI_UNSUPPORTED   If input size is greater than the maximum
> supported buffer size.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableExLibGetScratchBuffer (
> +  IN OUT UINTN  *ScratchBufferSize,
> +  OUT    VOID   **ScratchBuffer
> +  );
> +
> +/**
> +  This function is to check if the remaining variable space is enough to set
> +  all Variables from argument list successfully. The purpose of the check
> +  is to keep the consistency of the Variables to be in variable storage.
> +
> +  Note: Variables are assumed to be in same storage.
> +  The set sequence of Variables will be same with the sequence of VariableEntry
> from argument list,
> +  so follow the argument sequence to check the Variables.
> +
> +  @param[in] Attributes         Variable attributes for Variable entries.
> +  @param ...                    The variable argument list with type
> VARIABLE_ENTRY_CONSISTENCY *.
> +                                A NULL terminates the list. The VariableSize of
> +                                VARIABLE_ENTRY_CONSISTENCY is the variable data size as
> input.
> +                                It will be changed to variable total size as output.
> +
> +  @retval TRUE                  Have enough variable space to set the Variables
> successfully.
> +  @retval FALSE                 No enough variable space to set the Variables
> successfully.
> +
> +**/
> +BOOLEAN
> +EFIAPI
> +VariableExLibCheckRemainingSpaceForConsistency (
> +  IN UINT32  Attributes,
> +  ...
> +  );
> +
> +/**
> +  Return TRUE if at OS runtime.
> +
> +  @retval TRUE If at OS runtime.
> +  @retval FALSE If at boot time.
> +
> +**/
> +BOOLEAN
> +EFIAPI
> +VariableExLibAtRuntime (
> +  VOID
> +  );
> +
> +/**
> +  Is user variable?
> +
> +  @param[in] Variable   Pointer to variable header.
> +
> +  @retval TRUE          User variable.
> +  @retval FALSE         System variable.
> +
> +**/
> +BOOLEAN
> +IsUserVariable (
> +  IN VARIABLE_HEADER  *Variable
> +  );
> +
> +/**
> +
> +  Variable store garbage collection and reclaim operation.
> +
> +  @param[in]      VariableBase            Base address of variable store.
> +  @param[out]     LastVariableOffset      Offset of last variable.
> +  @param[in]      IsVolatile              The variable store is volatile or not;
> +                                          if it is non-volatile, need FTW.
> +  @param[in, out] UpdatingPtrTrack        Pointer to updating variable pointer
> track structure.
> +  @param[in]      NewVariable             Pointer to new variable.
> +  @param[in]      NewVariableSize         New variable size.
> +
> +  @return EFI_SUCCESS                  Reclaim operation has finished successfully.
> +  @return EFI_OUT_OF_RESOURCES         No enough memory resources or
> variable space.
> +  @return Others                       Unexpect error happened during reclaim
> operation.
> +
> +**/
> +EFI_STATUS
> +Reclaim (
> +  IN     EFI_PHYSICAL_ADDRESS    VariableBase,
> +  OUT    UINTN                   *LastVariableOffset,
> +  IN     BOOLEAN                 IsVolatile,
> +  IN OUT VARIABLE_POINTER_TRACK  *UpdatingPtrTrack,
> +  IN     VARIABLE_HEADER         *NewVariable,
> +  IN     UINTN                   NewVariableSize
> +  );
> +
> +/**
> +
> +  This function writes data to the FWH at the correct LBA even if the LBAs
> +  are fragmented.
> +
> +  @param Global                  Pointer to VARIABLE_GLOBAL structure.
> +  @param Volatile                Point out the Variable is Volatile or Non-Volatile.
> +  @param SetByIndex              TRUE if target pointer is given as index.
> +                                 FALSE if target pointer is absolute.
> +  @param Fvb                     Pointer to the writable FVB protocol.
> +  @param DataPtrIndex            Pointer to the Data from the end of
> VARIABLE_STORE_HEADER
> +                                 structure.
> +  @param DataSize                Size of data to be written.
> +  @param Buffer                  Pointer to the buffer from which data is written.
> +
> +  @retval EFI_INVALID_PARAMETER  Parameters not valid.
> +  @retval EFI_UNSUPPORTED        Fvb is a NULL for Non-Volatile variable
> update.
> +  @retval EFI_OUT_OF_RESOURCES   The remaining size is not enough.
> +  @retval EFI_SUCCESS            Variable store successfully updated.
> +
> +**/
> +EFI_STATUS
> +UpdateVariableStore (
> +  IN VARIABLE_GLOBAL                     *Global,
> +  IN BOOLEAN                             Volatile,
> +  IN BOOLEAN                             SetByIndex,
> +  IN EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  *Fvb,
> +  IN UINTN                               DataPtrIndex,
> +  IN UINT32                              DataSize,
> +  IN UINT8                               *Buffer
> +  );
> +
> +/**
> +  Update partial data of a variable on NV storage and/or cached copy.
> +
> +  @param[in]  VariableInfo  Pointer to a variable with detailed information.
> +  @param[in]  Offset        Offset to write from.
> +  @param[in]  Size          Size of data Buffer to update.
> +  @param[in]  Buffer        Pointer to data buffer to update.
> +
> +  @retval EFI_SUCCESS             The variable data was updated successfully.
> +  @retval EFI_UNSUPPORTED         If this function is called directly in runtime.
> +  @retval EFI_INVALID_PARAMETER   If VariableInfo, Buffer or Size are not
> valid.
> +  @retval Others                  Failed to update NV storage or variable cache.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableExLibUpdateNvVariable (
> +  IN  PROTECTED_VARIABLE_INFO  *VariableInfo,
> +  IN  UINTN                    Offset,
> +  IN  UINT32                   Size,
> +  IN  UINT8                    *Buffer
> +  );
> +
> +/**
> +  Finds the given variable in a variable store in SMM.
> +
> +  Caution: This function may receive untrusted input.
> +  The data size is external input, so this function will validate it carefully to
> avoid buffer overflow.

[JianJW] Too long line. Wrap it to within 80 characters for each line.

> +
> +  @param[in]      VariableName       Name of Variable to be found.
> +  @param[in]      VendorGuid         Variable vendor GUID.
> +  @param[out]     Attributes         Attribute value of the variable found.
> +  @param[in, out] DataSize           Size of Data found. If size is less than the
> +                                     data, this value contains the required size.
> +  @param[out]     Data               Data pointer.
> +
> +  @retval EFI_SUCCESS                Found the specified variable.
> +  @retval EFI_INVALID_PARAMETER      Invalid parameter.
> +  @retval EFI_NOT_FOUND              The specified variable could not be found.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +FindVariableInSmm (
> +  IN      CHAR16    *VariableName,
> +  IN      EFI_GUID  *VendorGuid,
> +  OUT     UINT32    *Attributes OPTIONAL,
> +  IN OUT  UINTN     *DataSize,
> +  OUT     VOID      *Data OPTIONAL
> +  );
> +
> +#endif
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableNonVolat
> ile.h
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableNonVolat
> ile.h
> new file mode 100644
> index 000000000000..a84db4877c13
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableNonVolat
> ile.h
> @@ -0,0 +1,67 @@
> +/** @file
> +  Common variable non-volatile store routines.
> +
> +Copyright (c) 2019-2022, Intel Corporation. All rights reserved.<BR>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#ifndef VARIABLE_NON_VOLATILE_H_
> +#define VARIABLE_NON_VOLATILE_H_
> +
> +#include "Variable.h"
> +
> +/**
> +  Get non-volatile maximum variable size.
> +
> +  @return Non-volatile maximum variable size.
> +
> +**/
> +UINTN
> +GetNonVolatileMaxVariableSize (
> +  VOID
> +  );
> +
> +/**
> +  Init emulated non-volatile variable store.
> +
> +  @param[out] VariableStoreBase Output pointer to emulated non-volatile
> variable store base.
> +
> +  @retval EFI_SUCCESS           Function successfully executed.
> +  @retval EFI_OUT_OF_RESOURCES  Fail to allocate enough memory resource.
> +
> +**/
> +EFI_STATUS
> +InitEmuNonVolatileVariableStore (
> +  EFI_PHYSICAL_ADDRESS  *VariableStoreBase
> +  );
> +
> +/**
> +  Init real non-volatile variable store.
> +
> +  @param[out] VariableStoreBase Output pointer to real non-volatile variable
> store base.
> +
> +  @retval EFI_SUCCESS           Function successfully executed.
> +  @retval EFI_OUT_OF_RESOURCES  Fail to allocate enough memory resource.
> +  @retval EFI_VOLUME_CORRUPTED  Variable Store or Firmware Volume for
> Variable Store is corrupted.
> +
> +**/
> +EFI_STATUS
> +InitRealNonVolatileVariableStore (
> +  OUT EFI_PHYSICAL_ADDRESS  *VariableStoreBase
> +  );
> +
> +/**
> +  Init non-volatile variable store.
> +
> +  @retval EFI_SUCCESS           Function successfully executed.
> +  @retval EFI_OUT_OF_RESOURCES  Fail to allocate enough memory resource.
> +  @retval EFI_VOLUME_CORRUPTED  Variable Store or Firmware Volume for
> Variable Store is corrupted.
> +
> +**/
> +EFI_STATUS
> +InitNonVolatileVariableStore (
> +  VOID
> +  );
> +
> +#endif
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableParsing.h
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableParsing.h
> new file mode 100644
> index 000000000000..5b040e00982f
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableParsing.h
> @@ -0,0 +1,424 @@
> +/** @file
> +  Functions in this module are associated with variable parsing operations and
> +  are intended to be usable across variable driver source files.
> +
> +Copyright (c) 2019 - 2022, Intel Corporation. All rights reserved.<BR>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#ifndef VARIABLE_PARSING_H_
> +#define VARIABLE_PARSING_H_
> +
> +#include <Guid/ImageAuthentication.h>
> +#include "Variable.h"
> +
> +/**
> +
> +  This code checks if variable header is valid or not.
> +
> +  @param[in] Variable           Pointer to the Variable Header.
> +  @param[in] VariableStoreEnd   Pointer to the Variable Store End.
> +  @param[in] AuthFormat         Auth-variable indicator.
> +
> +  @retval TRUE              Variable header is valid.
> +  @retval FALSE             Variable header is not valid.
> +
> +**/
> +BOOLEAN
> +IsValidVariableHeader (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  VARIABLE_HEADER  *VariableStoreEnd,
> +  IN  BOOLEAN          AuthFormat
> +  );
> +
> +/**
> +
> +  This code gets the current status of Variable Store.
> +
> +  @param[in] VarStoreHeader  Pointer to the Variable Store Header.
> +
> +  @retval EfiRaw         Variable store status is raw.
> +  @retval EfiValid       Variable store status is valid.
> +  @retval EfiInvalid     Variable store status is invalid.
> +
> +**/
> +VARIABLE_STORE_STATUS
> +GetVariableStoreStatus (
> +  IN VARIABLE_STORE_HEADER  *VarStoreHeader
> +  );
> +
> +/**
> +  This code gets the size of variable header.
> +
> +  @param[in]  AuthFormat    TRUE indicates authenticated variables are used.
> +                            FALSE indicates authenticated variables are not used.
> +
> +  @return Size of variable header in bytes in type UINTN.
> +
> +**/
> +UINTN
> +GetVariableHeaderSize (
> +  IN  BOOLEAN  AuthFormat
> +  );
> +
> +/**
> +
> +  This code gets the size of name of variable.
> +
> +  @param[in]  Variable      Pointer to the variable header.
> +  @param[in]  AuthFormat    TRUE indicates authenticated variables are used.
> +                            FALSE indicates authenticated variables are not used.
> +
> +  @return UINTN          Size of variable in bytes.
> +
> +**/
> +UINTN
> +NameSizeOfVariable (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  BOOLEAN          AuthFormat
> +  );
> +
> +/**
> +  This code sets the size of name of variable.
> +
> +  @param[in]  Variable      Pointer to the Variable Header.
> +  @param[in]  NameSize      Name size to set.
> +  @param[in]  AuthFormat    TRUE indicates authenticated variables are used.
> +                            FALSE indicates authenticated variables are not used.
> +
> +**/
> +VOID
> +SetNameSizeOfVariable (
> +  IN VARIABLE_HEADER  *Variable,
> +  IN UINTN            NameSize,
> +  IN BOOLEAN          AuthFormat
> +  );
> +
> +/**
> +
> +  This code gets the size of variable data.
> +
> +  @param[in]  Variable      Pointer to the Variable Header.
> +  @param[in]  AuthFormat    TRUE indicates authenticated variables are used.
> +                            FALSE indicates authenticated variables are not used.
> +
> +  @return Size of variable in bytes.
> +
> +**/
> +UINTN
> +DataSizeOfVariable (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  BOOLEAN          AuthFormat
> +  );
> +
> +/**
> +  This code sets the size of variable data.
> +
> +  @param[in] Variable   Pointer to the Variable Header.
> +  @param[in] DataSize   Data size to set.
> +  @param[in] AuthFormat TRUE indicates authenticated variables are used.
> +                        FALSE indicates authenticated variables are not used.
> +
> +**/
> +VOID
> +SetDataSizeOfVariable (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  UINTN            DataSize,
> +  IN  BOOLEAN          AuthFormat
> +  );
> +
> +/**
> +
> +  This code gets the pointer to the variable name.
> +
> +  @param[in] Variable     Pointer to the Variable Header.
> +  @param[in] AuthFormat   TRUE indicates authenticated variables are used.
> +                          FALSE indicates authenticated variables are not used.
> +
> +  @return Pointer to Variable Name which is Unicode encoding.
> +
> +**/
> +CHAR16 *
> +GetVariableNamePtr (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  BOOLEAN          AuthFormat
> +  );
> +
> +/**
> +  This code gets the pointer to the variable guid.
> +
> +  @param[in] Variable     Pointer to the Variable Header.
> +  @param[in] AuthFormat   TRUE indicates authenticated variables are used.
> +                          FALSE indicates authenticated variables are not used.
> +
> +  @return A EFI_GUID* pointer to Vendor Guid.
> +
> +**/
> +EFI_GUID *
> +GetVendorGuidPtr (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  BOOLEAN          AuthFormat
> +  );
> +
> +/**
> +
> +  This code gets the pointer to the variable data.
> +
> +  @param[in] Variable     Pointer to the Variable Header.
> +  @param[in] AuthFormat   TRUE indicates authenticated variables are used.
> +                          FALSE indicates authenticated variables are not used.
> +
> +  @return Pointer to Variable Data.
> +
> +**/
> +UINT8 *
> +GetVariableDataPtr (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  BOOLEAN          AuthFormat
> +  );
> +
> +/**
> +  This code gets the variable data offset related to variable header.
> +
> +  @param[in] Variable     Pointer to the Variable Header.
> +  @param[in] AuthFormat   TRUE indicates authenticated variables are used.
> +                          FALSE indicates authenticated variables are not used.
> +
> +  @return Variable Data offset.
> +
> +**/
> +UINTN
> +GetVariableDataOffset (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  BOOLEAN          AuthFormat
> +  );
> +
> +/**
> +  Get variable data payload.
> +
> +  @param[in]      Variable     Pointer to the Variable Header.
> +  @param[out]     Data         Pointer to buffer used to store the variable data.
> +  @param[in]      DataSize     Size of buffer passed by Data.
> +  @param[out]     DataSize     Size of data copied into Data buffer.
> +  @param[in]      AuthFlag     Auth-variable indicator.
> +
> +  @return EFI_SUCCESS             Data was fetched.
> +  @return EFI_INVALID_PARAMETER   DataSize is NULL.
> +  @return EFI_BUFFER_TOO_SMALL    DataSize is smaller than size of variable
> data.
> +
> +**/
> +EFI_STATUS
> +GetVariableData (
> +  IN      VARIABLE_HEADER  *Variable,
> +  IN  OUT VOID             *Data,
> +  IN  OUT UINT32           *DataSize,
> +  IN      BOOLEAN          AuthFlag
> +  );
> +
> +/**
> +
> +  This code gets the pointer to the next variable header.
> +
> +  @param[in] Variable     Pointer to the Variable Header.
> +  @param[in] AuthFormat   TRUE indicates authenticated variables are used.
> +                          FALSE indicates authenticated variables are not used.
> +
> +  @return Pointer to next variable header.
> +
> +**/
> +VARIABLE_HEADER *
> +GetNextVariablePtr (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  BOOLEAN          AuthFormat
> +  );
> +
> +/**
> +
> +  Gets the pointer to the first variable header in given variable store area.
> +
> +  @param[in] VarStoreHeader  Pointer to the Variable Store Header.
> +
> +  @return Pointer to the first variable header.
> +
> +**/
> +VARIABLE_HEADER *
> +GetStartPointer (
> +  IN VARIABLE_STORE_HEADER  *VarStoreHeader
> +  );
> +
> +/**
> +
> +  Gets the pointer to the end of the variable storage area.
> +
> +  This function gets pointer to the end of the variable storage
> +  area, according to the input variable store header.
> +
> +  @param[in] VarStoreHeader  Pointer to the Variable Store Header.
> +
> +  @return Pointer to the end of the variable storage area.
> +
> +**/
> +VARIABLE_HEADER *
> +GetEndPointer (
> +  IN VARIABLE_STORE_HEADER  *VarStoreHeader
> +  );
> +
> +/**
> +  Compare two EFI_TIME data.
> +
> +
> +  @param[in] FirstTime       A pointer to the first EFI_TIME data.
> +  @param[in] SecondTime      A pointer to the second EFI_TIME data.
> +
> +  @retval  TRUE              The FirstTime is not later than the SecondTime.
> +  @retval  FALSE             The FirstTime is later than the SecondTime.
> +
> +**/
> +BOOLEAN
> +VariableCompareTimeStampInternal (
> +  IN EFI_TIME  *FirstTime,
> +  IN EFI_TIME  *SecondTime
> +  );
> +
> +/**
> +  Find the variable in the specified variable store.
> +
> +  @param[in]       VariableName        Name of the variable to be found
> +  @param[in]       VendorGuid          Vendor GUID to be found.
> +  @param[in]       IgnoreRtCheck       Ignore EFI_VARIABLE_RUNTIME_ACCESS
> attribute
> +                                       check at runtime when searching variable.
> +  @param[in, out]  PtrTrack            Variable Track Pointer structure that contains
> Variable Information.
> +  @param[in]       AuthFormat          TRUE indicates authenticated variables are
> used.
> +                                       FALSE indicates authenticated variables are not used.
> +
> +  @retval          EFI_SUCCESS         Variable found successfully
> +  @retval          EFI_NOT_FOUND       Variable not found
> +**/
> +EFI_STATUS
> +FindVariableEx (
> +  IN     CHAR16                  *VariableName,
> +  IN     EFI_GUID                *VendorGuid,
> +  IN     BOOLEAN                 IgnoreRtCheck,
> +  IN OUT VARIABLE_POINTER_TRACK  *PtrTrack,
> +  IN     BOOLEAN                 AuthFormat
> +  );
> +
> +/**
> +  This code finds the next available variable.
> +
> +  Caution: This function may receive untrusted input.
> +  This function may be invoked in SMM mode. This function will do basic
> validation, before parse the data.
> +
> +  @param[in]  VariableName      Pointer to variable name.
> +  @param[in]  VendorGuid        Variable Vendor Guid.
> +  @param[in]  VariableStoreList A list of variable stores that should be used to
> get the next variable.
> +                                The maximum number of entries is the max value of
> VARIABLE_STORE_TYPE.
> +  @param[out] VariablePtr       Pointer to variable header address.
> +  @param[in]  AuthFormat        TRUE indicates authenticated variables are used.
> +                                FALSE indicates authenticated variables are not used.
> +
> +  @retval EFI_SUCCESS           The function completed successfully.
> +  @retval EFI_NOT_FOUND         The next variable was not found.
> +  @retval EFI_INVALID_PARAMETER If VariableName is not an empty string,
> while VendorGuid is NULL.
> +  @retval EFI_INVALID_PARAMETER The input values of VariableName and
> VendorGuid are not a name and
> +                                GUID of an existing variable.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableServiceGetNextVariableInternal (
> +  IN  CHAR16                 *VariableName,
> +  IN  EFI_GUID               *VendorGuid,
> +  IN  VARIABLE_STORE_HEADER  **VariableStoreList,
> +  OUT VARIABLE_HEADER        **VariablePtr,
> +  IN  BOOLEAN                AuthFormat
> +  );
> +
> +/**
> +  Routine used to track statistical information about variable usage.
> +  The data is stored in the EFI system table so it can be accessed later.
> +  VariableInfo.efi can dump out the table. Only Boot Services variable
> +  accesses are tracked by this code. The PcdVariableCollectStatistics
> +  build flag controls if this feature is enabled.
> +
> +  A read that hits in the cache will have Read and Cache true for
> +  the transaction. Data is allocated by this routine, but never
> +  freed.
> +
> +  @param[in]      VariableName   Name of the Variable to track.
> +  @param[in]      VendorGuid     Guid of the Variable to track.
> +  @param[in]      Volatile       TRUE if volatile FALSE if non-volatile.
> +  @param[in]      Read           TRUE if GetVariable() was called.
> +  @param[in]      Write          TRUE if SetVariable() was called.
> +  @param[in]      Delete         TRUE if deleted via SetVariable().
> +  @param[in]      Cache          TRUE for a cache hit.
> +  @param[in,out]  VariableInfo   Pointer to a pointer of VARIABLE_INFO_ENTRY
> structures.
> +
> +**/
> +VOID
> +UpdateVariableInfo (
> +  IN  CHAR16                  *VariableName,
> +  IN  EFI_GUID                *VendorGuid,
> +  IN  BOOLEAN                 Volatile,
> +  IN  BOOLEAN                 Read,
> +  IN  BOOLEAN                 Write,
> +  IN  BOOLEAN                 Delete,
> +  IN  BOOLEAN                 Cache,
> +  IN OUT VARIABLE_INFO_ENTRY  **VariableInfo
> +  );
> +
> +/**
> +
> +  Retrieve details of the variable next to given variable within VariableStore.
> +
> +  If VariableInfo->StoreIndex is invalid, the first one in VariableStore is returned.
> +
> +  @param[in,out] VariableInfo             Pointer to variable information.
> +
> +  @retval EFI_INVALID_PARAMETER  VariableInfo or VariableStore is NULL.
> +  @retval EFI_NOT_FOUND          If the end of VariableStore is reached.
> +  @retval EFI_SUCCESS            The next variable is retrieved successfully.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +GetNextVariableInfo (
> +  IN OUT  PROTECTED_VARIABLE_INFO  *VariableInfo
> +  );
> +
> +/**
> +
> +  Retrieve details about a variable and return them in VariableInfo->Header.
> +
> +  If VariableInfo->Buffer is given, this function will calculate its offset
> +  relative to given variable storage via VariableStore; Otherwise, it will try
> +  other internal variable storages or cached copies. It's assumed that, for all
> +  copies of NV variable storage, all variables are stored in the same relative
> +  position. If VariableInfo->Buffer is found in the range of any storage copies,
> +  its offset relative to that storage should be the same in other copies.
> +
> +  If VariableInfo->Offset is given (non-zero) but not VariableInfo->Buffer,
> +  this function will return the variable memory address inside VariableStore,
> +  if given, via VariableInfo->Address; Otherwise, the address of other storage
> +  copies will be returned, if any.
> +
> +  For a new variable whose offset has not been determined, a value of -1 as
> +  VariableInfo->Offset should be passed to skip the offset calculation.
> +
> +  @param VariableInfo             Pointer to variable information.
> +
> +  @retval EFI_INVALID_PARAMETER  VariableInfo is NULL or both VariableInfo-
> >Address
> +                                 and VariableInfo->Offset are NULL (0).
> +  @retval EFI_NOT_FOUND          If given Address or Offset is out of range of
> +                                 any given or internal storage copies.
> +  @retval EFI_SUCCESS            Variable details are retrieved successfully.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +GetVariableInfo (
> +  IN OUT  PROTECTED_VARIABLE_INFO  *VariableInfo
> +  );
> +
> +#endif
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeC
> ache.h
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeC
> ache.h
> new file mode 100644
> index 000000000000..77dbce0f907c
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeC
> ache.h
> @@ -0,0 +1,51 @@
> +/** @file
> +  The common variable volatile store routines shared by the DXE_RUNTIME
> variable
> +  module and the DXE_SMM variable module.
> +
> +Copyright (c) 2019-2022, Intel Corporation. All rights reserved.<BR>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#ifndef VARIABLE_RUNTIME_CACHE_H_
> +#define VARIABLE_RUNTIME_CACHE_H_
> +
> +#include "Variable.h"
> +
> +/**
> +  Copies any pending updates to runtime variable caches.
> +
> +  @retval EFI_UNSUPPORTED         The volatile store to be updated is not
> initialized properly.
> +  @retval EFI_SUCCESS             The volatile store was updated successfully.
> +
> +**/
> +EFI_STATUS
> +FlushPendingRuntimeVariableCacheUpdates (
> +  VOID
> +  );
> +
> +/**
> +  Synchronizes the runtime variable caches with all pending updates outside
> runtime.
> +
> +  Ensures all conditions are met to maintain coherency for runtime cache
> updates. This function will attempt
> +  to write the given update (and any other pending updates) if the ReadLock is
> available. Otherwise, the
> +  update is added as a pending update for the given variable store and it will be
> flushed to the runtime cache
> +  at the next opportunity the ReadLock is available.
> +
> +  @param[in] VariableRuntimeCache Variable runtime cache structure for the
> runtime cache being synchronized.
> +  @param[in] Offset               Offset in bytes to apply the update.
> +  @param[in] Length               Length of data in bytes of the update.
> +
> +  @retval EFI_SUCCESS             The update was added as a pending update
> successfully. If the variable runtime
> +                                  cache ReadLock was available, the runtime cache was
> updated successfully.
> +  @retval EFI_UNSUPPORTED         The volatile store to be updated is not
> initialized properly.
> +
> +**/
> +EFI_STATUS
> +SynchronizeRuntimeVariableCache (
> +  IN  VARIABLE_RUNTIME_CACHE  *VariableRuntimeCache,
> +  IN  UINTN                   Offset,
> +  IN  UINTN                   Length
> +  );
> +
> +#endif
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/Measurement.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/Measurement.c
> new file mode 100644
> index 000000000000..c15cce97165d
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/Measurement.c
> @@ -0,0 +1,343 @@
> +/** @file
> +  Measure TCG required variable.
> +
> +Copyright (c) 2013 - 2017, Intel Corporation. All rights reserved.<BR>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <PiDxe.h>
> +#include <Guid/ImageAuthentication.h>
> +#include <IndustryStandard/UefiTcgPlatform.h>
> +
> +#include <Library/UefiBootServicesTableLib.h>
> +#include <Library/UefiRuntimeServicesTableLib.h>
> +#include <Library/MemoryAllocationLib.h>
> +#include <Library/BaseMemoryLib.h>
> +#include <Library/DebugLib.h>
> +#include <Library/BaseLib.h>
> +#include <Library/TpmMeasurementLib.h>
> +
> +#include "PrivilegePolymorphic.h"
> +
> +typedef struct {
> +  CHAR16      *VariableName;
> +  EFI_GUID    *VendorGuid;
> +} VARIABLE_TYPE;
> +
> +VARIABLE_TYPE  mVariableType[] = {
> +  { EFI_SECURE_BOOT_MODE_NAME,    &gEfiGlobalVariableGuid        },
> +  { EFI_PLATFORM_KEY_NAME,        &gEfiGlobalVariableGuid        },
> +  { EFI_KEY_EXCHANGE_KEY_NAME,    &gEfiGlobalVariableGuid        },
> +  { EFI_IMAGE_SECURITY_DATABASE,  &gEfiImageSecurityDatabaseGuid },
> +  { EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid },
> +  { EFI_IMAGE_SECURITY_DATABASE2, &gEfiImageSecurityDatabaseGuid },
> +};
> +
> +//
> +// "SecureBoot" may update following PK Del/Add
> +//  Cache its value to detect value update
> +//
> +UINT8  *mSecureBootVarData    = NULL;
> +UINTN  mSecureBootVarDataSize = 0;
> +
> +/**
> +  This function will return if this variable is SecureBootPolicy Variable.
> +
> +  @param[in]  VariableName      A Null-terminated string that is the name of the
> vendor's variable.
> +  @param[in]  VendorGuid        A unique identifier for the vendor.
> +
> +  @retval TRUE  This is SecureBootPolicy Variable
> +  @retval FALSE This is not SecureBootPolicy Variable
> +**/
> +BOOLEAN
> +IsSecureBootPolicyVariable (
> +  IN CHAR16    *VariableName,
> +  IN EFI_GUID  *VendorGuid
> +  )
> +{
> +  UINTN  Index;
> +
> +  for (Index = 0; Index < sizeof (mVariableType)/sizeof (mVariableType[0]);
> Index++) {
> +    if ((StrCmp (VariableName, mVariableType[Index].VariableName) == 0) &&
> +        (CompareGuid (VendorGuid, mVariableType[Index].VendorGuid)))
> +    {
> +      return TRUE;
> +    }
> +  }
> +
> +  return FALSE;
> +}
> +
> +/**
> +  Measure and log an EFI variable, and extend the measurement result into a
> specific PCR.
> +
> +  @param[in]  VarName           A Null-terminated string that is the name of the
> vendor's variable.
> +  @param[in]  VendorGuid        A unique identifier for the vendor.
> +  @param[in]  VarData           The content of the variable data.
> +  @param[in]  VarSize           The size of the variable data.
> +
> +  @retval EFI_SUCCESS           Operation completed successfully.
> +  @retval EFI_OUT_OF_RESOURCES  Out of memory.
> +  @retval EFI_DEVICE_ERROR      The operation was unsuccessful.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +MeasureVariable (
> +  IN      CHAR16    *VarName,
> +  IN      EFI_GUID  *VendorGuid,
> +  IN      VOID      *VarData,
> +  IN      UINTN     VarSize
> +  )
> +{
> +  EFI_STATUS          Status;
> +  UINTN               VarNameLength;
> +  UEFI_VARIABLE_DATA  *VarLog;
> +  UINT32              VarLogSize;
> +
> +  ASSERT ((VarSize == 0 && VarData == NULL) || (VarSize != 0 && VarData !=
> NULL));
> +
> +  VarNameLength = StrLen (VarName);
> +  VarLogSize    = (UINT32)(sizeof (*VarLog) + VarNameLength * sizeof
> (*VarName) + VarSize
> +                           - sizeof (VarLog->UnicodeName) - sizeof (VarLog-
> >VariableData));
> +
> +  VarLog = (UEFI_VARIABLE_DATA *)AllocateZeroPool (VarLogSize);
> +  if (VarLog == NULL) {
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +
> +  CopyMem (&VarLog->VariableName, VendorGuid, sizeof (VarLog-
> >VariableName));
> +  VarLog->UnicodeNameLength  = VarNameLength;
> +  VarLog->VariableDataLength = VarSize;
> +  CopyMem (
> +    VarLog->UnicodeName,
> +    VarName,
> +    VarNameLength * sizeof (*VarName)
> +    );
> +  if (VarSize != 0) {
> +    CopyMem (
> +      (CHAR16 *)VarLog->UnicodeName + VarNameLength,
> +      VarData,
> +      VarSize
> +      );
> +  }
> +
> +  DEBUG ((DEBUG_INFO, "VariableDxe: MeasureVariable (Pcr - %x, EventType -
>  %x, ", (UINTN)7, (UINTN)EV_EFI_VARIABLE_DRIVER_CONFIG));
> +  DEBUG ((DEBUG_INFO, "VariableName - %s, VendorGuid - %g)\n", VarName,
> VendorGuid));
> +
> +  Status = TpmMeasureAndLogData (
> +             7,
> +             EV_EFI_VARIABLE_DRIVER_CONFIG,
> +             VarLog,
> +             VarLogSize,
> +             VarLog,
> +             VarLogSize
> +             );
> +  FreePool (VarLog);
> +  return Status;
> +}
> +
> +/**
> +  Returns the status whether get the variable success. The function retrieves
> +  variable  through the UEFI Runtime Service GetVariable().  The
> +  returned buffer is allocated using AllocatePool().  The caller is responsible
> +  for freeing this buffer with FreePool().
> +
> +  This API is only invoked in boot time. It may NOT be invoked at runtime.
> +
> +  @param[in]  Name  The pointer to a Null-terminated Unicode string.
> +  @param[in]  Guid  The pointer to an EFI_GUID structure
> +  @param[out] Value The buffer point saved the variable info.
> +  @param[out] Size  The buffer size of the variable.
> +
> +  @return EFI_OUT_OF_RESOURCES      Allocate buffer failed.
> +  @return EFI_SUCCESS               Find the specified variable.
> +  @return Others Errors             Return errors from call to gRT->GetVariable.
> +
> +**/
> +EFI_STATUS
> +InternalGetVariable (
> +  IN CONST CHAR16    *Name,
> +  IN CONST EFI_GUID  *Guid,
> +  OUT VOID           **Value,
> +  OUT UINTN          *Size
> +  )
> +{
> +  EFI_STATUS  Status;
> +  UINTN       BufferSize;
> +
> +  //
> +  // Try to get the variable size.
> +  //
> +  BufferSize = 0;
> +  *Value     = NULL;
> +  if (Size != NULL) {
> +    *Size = 0;
> +  }
> +
> +  Status = gRT->GetVariable ((CHAR16 *)Name, (EFI_GUID *)Guid, NULL,
> &BufferSize, *Value);
> +  if (Status != EFI_BUFFER_TOO_SMALL) {
> +    return Status;
> +  }
> +
> +  //
> +  // Allocate buffer to get the variable.
> +  //
> +  *Value = AllocatePool (BufferSize);
> +  ASSERT (*Value != NULL);
> +  if (*Value == NULL) {
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +
> +  //
> +  // Get the variable data.
> +  //
> +  Status = gRT->GetVariable ((CHAR16 *)Name, (EFI_GUID *)Guid, NULL,
> &BufferSize, *Value);
> +  if (EFI_ERROR (Status)) {
> +    FreePool (*Value);
> +    *Value = NULL;
> +  }
> +
> +  if (Size != NULL) {
> +    *Size = BufferSize;
> +  }
> +
> +  return Status;
> +}
> +
> +/**
> +  SecureBoot Hook for SetVariable.
> +
> +  @param[in] VariableName                 Name of Variable to be found.
> +  @param[in] VendorGuid                   Variable vendor GUID.
> +
> +**/
> +VOID
> +EFIAPI
> +SecureBootHook (
> +  IN CHAR16    *VariableName,
> +  IN EFI_GUID  *VendorGuid
> +  )
> +{
> +  EFI_STATUS  Status;
> +  UINTN       VariableDataSize;
> +  VOID        *VariableData;
> +
> +  if (!IsSecureBootPolicyVariable (VariableName, VendorGuid)) {
> +    return;
> +  }
> +
> +  //
> +  // We should NOT use Data and DataSize here,because it may include
> signature,
> +  // or is just partial with append attributes, or is deleted.
> +  // We should GetVariable again, to get full variable content.
> +  //
> +  Status = InternalGetVariable (
> +             VariableName,
> +             VendorGuid,
> +             &VariableData,
> +             &VariableDataSize
> +             );
> +  if (EFI_ERROR (Status)) {
> +    //
> +    // Measure DBT only if present and not empty
> +    //
> +    if ((StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE2) == 0) &&
> +        CompareGuid (VendorGuid, &gEfiImageSecurityDatabaseGuid))
> +    {
> +      DEBUG ((DEBUG_INFO, "Skip measuring variable %s since it's deleted\n",
> EFI_IMAGE_SECURITY_DATABASE2));
> +      return;
> +    } else {
> +      VariableData     = NULL;
> +      VariableDataSize = 0;
> +    }
> +  }
> +
> +  Status = MeasureVariable (
> +             VariableName,
> +             VendorGuid,
> +             VariableData,
> +             VariableDataSize
> +             );
> +  DEBUG ((DEBUG_INFO, "MeasureBootPolicyVariable - %r\n", Status));
> +
> +  if (VariableData != NULL) {
> +    FreePool (VariableData);
> +  }
> +
> +  //
> +  // "SecureBoot" is 8bit & read-only. It can only be changed according to PK
> update
> +  //
> +  if ((StrCmp (VariableName, EFI_PLATFORM_KEY_NAME) == 0) &&
> +      CompareGuid (VendorGuid, &gEfiGlobalVariableGuid))
> +  {
> +    Status = InternalGetVariable (
> +               EFI_SECURE_BOOT_MODE_NAME,
> +               &gEfiGlobalVariableGuid,
> +               &VariableData,
> +               &VariableDataSize
> +               );
> +    if (EFI_ERROR (Status)) {
> +      return;
> +    }
> +
> +    //
> +    // If PK update is successful. "SecureBoot" shall always exist ever since
> variable write service is ready
> +    //
> +    ASSERT (mSecureBootVarData != NULL);
> +
> +    if (CompareMem (mSecureBootVarData, VariableData, VariableDataSize) !=
> 0) {
> +      FreePool (mSecureBootVarData);
> +      mSecureBootVarData     = VariableData;
> +      mSecureBootVarDataSize = VariableDataSize;
> +
> +      DEBUG ((DEBUG_INFO, "%s variable updated according to PK change.
> Remeasure the value!\n", EFI_SECURE_BOOT_MODE_NAME));
> +      Status = MeasureVariable (
> +                 EFI_SECURE_BOOT_MODE_NAME,
> +                 &gEfiGlobalVariableGuid,
> +                 mSecureBootVarData,
> +                 mSecureBootVarDataSize
> +                 );
> +      DEBUG ((DEBUG_INFO, "MeasureBootPolicyVariable - %r\n", Status));
> +    } else {
> +      //
> +      // "SecureBoot" variable is not changed
> +      //
> +      FreePool (VariableData);
> +    }
> +  }
> +
> +  return;
> +}
> +
> +/**
> +  Some Secure Boot Policy Variable may update following other variable
> changes(SecureBoot follows PK change, etc).
> +  Record their initial State when variable write service is ready.
> +
> +**/
> +VOID
> +EFIAPI
> +RecordSecureBootPolicyVarData (
> +  VOID
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  //
> +  // Record initial "SecureBoot" variable value.
> +  // It is used to detect SecureBoot variable change in SecureBootHook.
> +  //
> +  Status = InternalGetVariable (
> +             EFI_SECURE_BOOT_MODE_NAME,
> +             &gEfiGlobalVariableGuid,
> +             (VOID **)&mSecureBootVarData,
> +             &mSecureBootVarDataSize
> +             );
> +  if (EFI_ERROR (Status)) {
> +    //
> +    // Read could fail when Auth Variable solution is not supported
> +    //
> +    DEBUG ((DEBUG_INFO, "RecordSecureBootPolicyVarData GetVariable %s
> Status %x\n", EFI_SECURE_BOOT_MODE_NAME, Status));
> +  }
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/Reclaim.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/Reclaim.c
> new file mode 100644
> index 000000000000..a5b7f8a1fbe2
> --- /dev/null
> +++ b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/Reclaim.c
> @@ -0,0 +1,504 @@
> +/** @file
> +  Handles non-volatile variable store garbage collection, using FTW
> +  (Fault Tolerant Write) protocol.
> +
> +Copyright (c) 2006 - 2022, Intel Corporation. All rights reserved.<BR>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include "Variable.h"
> +#include "VariableNonVolatile.h"
> +#include "VariableParsing.h"
> +#include "VariableRuntimeCache.h"
> +
> +/**
> +  Gets LBA of block and offset by given address.
> +
> +  This function gets the Logical Block Address (LBA) of a firmware
> +  volume block containing the given address, and the offset of the
> +  address on the block.
> +
> +  @param  Address        Address which should be contained
> +                         by returned FVB handle.
> +  @param  Lba            Pointer to LBA for output.
> +  @param  Offset         Pointer to offset for output.
> +
> +  @retval EFI_SUCCESS    LBA and offset successfully returned.
> +  @retval EFI_NOT_FOUND  Fail to find FVB handle by address.
> +  @retval EFI_ABORTED    Fail to find valid LBA and offset.
> +
> +**/
> +EFI_STATUS
> +GetLbaAndOffsetByAddress (
> +  IN  EFI_PHYSICAL_ADDRESS  Address,
> +  OUT EFI_LBA               *Lba,
> +  OUT UINTN                 *Offset
> +  )
> +{
> +  EFI_STATUS                          Status;
> +  EFI_PHYSICAL_ADDRESS                FvbBaseAddress;
> +  EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  *Fvb;
> +  EFI_FIRMWARE_VOLUME_HEADER          *FwVolHeader;
> +  EFI_FV_BLOCK_MAP_ENTRY              *FvbMapEntry;
> +  UINT32                              LbaIndex;
> +
> +  Fvb     = NULL;
> +  *Lba    = (EFI_LBA)(-1);
> +  *Offset = 0;
> +
> +  //
> +  // Get the proper FVB protocol.
> +  //
> +  Status = GetFvbInfoByAddress (Address, NULL, &Fvb);
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  //
> +  // Get the Base Address of FV.
> +  //
> +  Status = Fvb->GetPhysicalAddress (Fvb, &FvbBaseAddress);
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  FwVolHeader = (EFI_FIRMWARE_VOLUME_HEADER
> *)((UINTN)FvbBaseAddress);
> +
> +  //
> +  // Get the (LBA, Offset) of Address.
> +  //
> +  if ((FwVolHeader->FvLength) > (FwVolHeader->HeaderLength)) {
> +    //
> +    // BUGBUG: Assume one FV has one type of BlockLength.
> +    //
> +    FvbMapEntry = &FwVolHeader->BlockMap[0];
> +    for (LbaIndex = 1; LbaIndex <= FvbMapEntry->NumBlocks; LbaIndex += 1) {
> +      if (Address < (FvbBaseAddress + FvbMapEntry->Length * LbaIndex)) {
> +        //
> +        // Found the (Lba, Offset).
> +        //
> +        *Lba    = LbaIndex - 1;
> +        *Offset = (UINTN)(Address - (FvbBaseAddress + FvbMapEntry->Length *
> (LbaIndex - 1)));
> +        return EFI_SUCCESS;
> +      }
> +    }
> +  }
> +
> +  return EFI_ABORTED;
> +}
> +
> +/**
> +  Writes a buffer to variable storage space, in the working block.
> +
> +  This function writes a buffer to variable storage space into a firmware
> +  volume block device. The destination is specified by parameter
> +  VariableBase. Fault Tolerant Write protocol is used for writing.
> +
> +  @param  VariableBase   Base address of variable to write
> +  @param  VariableBuffer Point to the variable data buffer.
> +
> +  @retval EFI_SUCCESS    The function completed successfully.
> +  @retval EFI_NOT_FOUND  Fail to locate Fault Tolerant Write protocol.
> +  @retval EFI_ABORTED    The function could not complete successfully.
> +
> +**/
> +EFI_STATUS
> +FtwVariableSpace (
> +  IN EFI_PHYSICAL_ADDRESS   VariableBase,
> +  IN VARIABLE_STORE_HEADER  *VariableBuffer
> +  )
> +{
> +  EFI_STATUS                         Status;
> +  EFI_HANDLE                         FvbHandle;
> +  EFI_LBA                            VarLba;
> +  UINTN                              VarOffset;
> +  UINTN                              FtwBufferSize;
> +  EFI_FAULT_TOLERANT_WRITE_PROTOCOL  *FtwProtocol;
> +
> +  //
> +  // Locate fault tolerant write protocol.
> +  //
> +  Status = GetFtwProtocol ((VOID **)&FtwProtocol);
> +  if (EFI_ERROR (Status)) {
> +    return EFI_NOT_FOUND;
> +  }
> +
> +  //
> +  // Locate Fvb handle by address.
> +  //
> +  Status = GetFvbInfoByAddress (VariableBase, &FvbHandle, NULL);
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  //
> +  // Get LBA and Offset by address.
> +  //
> +  Status = GetLbaAndOffsetByAddress (VariableBase, &VarLba, &VarOffset);
> +  if (EFI_ERROR (Status)) {
> +    return EFI_ABORTED;
> +  }
> +
> +  FtwBufferSize = ((VARIABLE_STORE_HEADER *)((UINTN)VariableBase))->Size;
> +  ASSERT (FtwBufferSize == VariableBuffer->Size);
> +
> +  //
> +  // FTW write record.
> +  //
> +  Status = FtwProtocol->Write (
> +                          FtwProtocol,
> +                          VarLba,                // LBA
> +                          VarOffset,             // Offset
> +                          FtwBufferSize,         // NumBytes
> +                          NULL,                  // PrivateData NULL
> +                          FvbHandle,             // Fvb Handle
> +                          (VOID *)VariableBuffer // write buffer
> +                          );
> +
> +  return Status;
> +}
> +
> +/**
> +
> +  Variable store garbage collection and reclaim operation.
> +
> +  @param[in]      VariableBase            Base address of variable store.
> +  @param[out]     LastVariableOffset      Offset of last variable.
> +  @param[in]      IsVolatile              The variable store is volatile or not;
> +                                          if it is non-volatile, need FTW.
> +  @param[in, out] UpdatingPtrTrack        Pointer to updating variable pointer
> track structure.
> +  @param[in]      NewVariable             Pointer to new variable.
> +  @param[in]      NewVariableSize         New variable size.
> +
> +  @return EFI_SUCCESS                  Reclaim operation has finished successfully.
> +  @return EFI_OUT_OF_RESOURCES         No enough memory resources or
> variable space.
> +  @return Others                       Unexpect error happened during reclaim
> operation.
> +
> +**/
> +EFI_STATUS
> +Reclaim (
> +  IN     EFI_PHYSICAL_ADDRESS    VariableBase,
> +  OUT    UINTN                   *LastVariableOffset,
> +  IN     BOOLEAN                 IsVolatile,
> +  IN OUT VARIABLE_POINTER_TRACK  *UpdatingPtrTrack,
> +  IN     VARIABLE_HEADER         *NewVariable,
> +  IN     UINTN                   NewVariableSize
> +  )
> +{
> +  VARIABLE_HEADER        *Variable;
> +  VARIABLE_HEADER        *AddedVariable;
> +  VARIABLE_HEADER        *NextVariable;
> +  VARIABLE_HEADER        *NextAddedVariable;
> +  VARIABLE_STORE_HEADER  *VariableStoreHeader;
> +  UINT8                  *ValidBuffer;
> +  UINTN                  MaximumBufferSize;
> +  UINTN                  VariableSize;
> +  UINTN                  NameSize;
> +  UINT8                  *CurrPtr;
> +  VOID                   *Point0;
> +  VOID                   *Point1;
> +  BOOLEAN                FoundAdded;
> +  EFI_STATUS             Status;
> +  EFI_STATUS             DoneStatus;
> +  UINTN                  CommonVariableTotalSize;
> +  UINTN                  CommonUserVariableTotalSize;
> +  UINTN                  HwErrVariableTotalSize;
> +  VARIABLE_HEADER        *UpdatingVariable;
> +  VARIABLE_HEADER        *UpdatingInDeletedTransition;
> +  BOOLEAN                AuthFormat;
> +
> +  AuthFormat                  = mVariableModuleGlobal->VariableGlobal.AuthFormat;
> +  UpdatingVariable            = NULL;
> +  UpdatingInDeletedTransition = NULL;
> +  if (UpdatingPtrTrack != NULL) {
> +    UpdatingVariable            = UpdatingPtrTrack->CurrPtr;
> +    UpdatingInDeletedTransition = UpdatingPtrTrack->InDeletedTransitionPtr;
> +  }
> +
> +  VariableStoreHeader = (VARIABLE_STORE_HEADER *)((UINTN)VariableBase);
> +
> +  CommonVariableTotalSize     = 0;
> +  CommonUserVariableTotalSize = 0;
> +  HwErrVariableTotalSize      = 0;
> +
> +  if (IsVolatile || mVariableModuleGlobal->VariableGlobal.EmuNvMode) {
> +    //
> +    // Start Pointers for the variable.
> +    //
> +    Variable          = GetStartPointer (VariableStoreHeader);
> +    MaximumBufferSize = sizeof (VARIABLE_STORE_HEADER);
> +
> +    while (IsValidVariableHeader (Variable, GetEndPointer (VariableStoreHeader),
> AuthFormat)) {
> +      NextVariable = GetNextVariablePtr (Variable, AuthFormat);
> +      if (((Variable->State == VAR_ADDED) || (Variable->State ==
> (VAR_IN_DELETED_TRANSITION & VAR_ADDED))) &&
> +          (Variable != UpdatingVariable) &&
> +          (Variable != UpdatingInDeletedTransition)
> +          )
> +      {
> +        VariableSize       = (UINTN)NextVariable - (UINTN)Variable;
> +        MaximumBufferSize += VariableSize;
> +      }
> +
> +      Variable = NextVariable;
> +    }
> +
> +    if (NewVariable != NULL) {
> +      //
> +      // Add the new variable size.
> +      //
> +      MaximumBufferSize += NewVariableSize;
> +    }
> +
> +    //
> +    // Reserve the 1 Bytes with Oxff to identify the
> +    // end of the variable buffer.
> +    //
> +    MaximumBufferSize += 1;
> +    ValidBuffer        = AllocatePool (MaximumBufferSize);
> +    if (ValidBuffer == NULL) {
> +      return EFI_OUT_OF_RESOURCES;
> +    }
> +  } else {
> +    //
> +    // For NV variable reclaim, don't allocate pool here and just use
> mNvVariableCache
> +    // as the buffer to reduce SMRAM consumption for SMM variable driver.
> +    //
> +    MaximumBufferSize = mNvVariableCache->Size;
> +    ValidBuffer       = (UINT8 *)mNvVariableCache;
> +  }
> +
> +  SetMem (ValidBuffer, MaximumBufferSize, 0xff);
> +
> +  //
> +  // Copy variable store header.
> +  //
> +  CopyMem (ValidBuffer, VariableStoreHeader, sizeof
> (VARIABLE_STORE_HEADER));
> +  CurrPtr = (UINT8 *)GetStartPointer ((VARIABLE_STORE_HEADER *)ValidBuffer);
> +
> +  //
> +  // Reinstall all ADDED variables as long as they are not identical to Updating
> Variable.
> +  //
> +  Variable = GetStartPointer (VariableStoreHeader);
> +  while (IsValidVariableHeader (Variable, GetEndPointer (VariableStoreHeader),
> AuthFormat)) {
> +    NextVariable = GetNextVariablePtr (Variable, AuthFormat);
> +    if ((Variable != UpdatingVariable) && (Variable->State == VAR_ADDED)) {
> +      VariableSize = (UINTN)NextVariable - (UINTN)Variable;
> +      CopyMem (CurrPtr, (UINT8 *)Variable, VariableSize);
> +      if (!IsVolatile) {
> +        (VOID)ProtectedVariableLibRefresh (
> +                (VARIABLE_HEADER *)CurrPtr,
> +                VariableSize,
> +                (UINTN)CurrPtr - (UINTN)ValidBuffer,
> +                FALSE
> +                );
> +
> +        if ((Variable->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
> +            == EFI_VARIABLE_HARDWARE_ERROR_RECORD)
> +        {
> +          HwErrVariableTotalSize += VariableSize;
> +        } else {
> +          CommonVariableTotalSize += VariableSize;
> +          if (IsUserVariable (Variable)) {
> +            CommonUserVariableTotalSize += VariableSize;
> +          }
> +        }
> +      }
> +
> +      CurrPtr += VariableSize;
> +    }
> +
> +    Variable = NextVariable;
> +  }
> +
> +  //
> +  // Reinstall all in delete transition variables.
> +  //
> +  Variable = GetStartPointer (VariableStoreHeader);
> +  while (IsValidVariableHeader (Variable, GetEndPointer (VariableStoreHeader),
> AuthFormat)) {
> +    NextVariable = GetNextVariablePtr (Variable, AuthFormat);
> +    if ((Variable != UpdatingVariable) && (Variable !=
> UpdatingInDeletedTransition) && (Variable->State ==
> (VAR_IN_DELETED_TRANSITION & VAR_ADDED)) &&
> +        (ProtectedVariableLibIsHmac (GetVariableNamePtr (Variable, AuthFormat))
> == FALSE))
> +    {
> +      FoundAdded    = FALSE;
> +      AddedVariable = GetStartPointer ((VARIABLE_STORE_HEADER *)ValidBuffer);
> +      while (IsValidVariableHeader (AddedVariable, GetEndPointer
> ((VARIABLE_STORE_HEADER *)ValidBuffer), AuthFormat)) {
> +        NextAddedVariable = GetNextVariablePtr (AddedVariable, AuthFormat);
> +        NameSize          = NameSizeOfVariable (AddedVariable, AuthFormat);
> +        if (CompareGuid (
> +              GetVendorGuidPtr (AddedVariable, AuthFormat),
> +              GetVendorGuidPtr (Variable, AuthFormat)
> +              ) && (NameSize == NameSizeOfVariable (Variable, AuthFormat)))
> +        {
> +          Point0 = (VOID *)GetVariableNamePtr (AddedVariable, AuthFormat);
> +          Point1 = (VOID *)GetVariableNamePtr (Variable, AuthFormat);
> +          if (CompareMem (Point0, Point1, NameSize) == 0) {
> +            FoundAdded = TRUE;
> +            break;
> +          }
> +        }
> +
> +        AddedVariable = NextAddedVariable;
> +      }
> +
> +      if (!FoundAdded) {
> +        //
> +        // Promote VAR_IN_DELETED_TRANSITION to VAR_ADDED.
> +        //
> +        VariableSize = (UINTN)NextVariable - (UINTN)Variable;
> +        CopyMem (CurrPtr, (UINT8 *)Variable, VariableSize);
> +        ((VARIABLE_HEADER *)CurrPtr)->State = VAR_ADDED;
> +        if (!IsVolatile) {
> +          (VOID)ProtectedVariableLibRefresh (
> +                  (VARIABLE_HEADER *)CurrPtr,
> +                  VariableSize,
> +                  (UINTN)CurrPtr - (UINTN)ValidBuffer,
> +                  FALSE
> +                  );
> +
> +          if ((Variable->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
> +              == EFI_VARIABLE_HARDWARE_ERROR_RECORD)
> +          {
> +            HwErrVariableTotalSize += VariableSize;
> +          } else {
> +            CommonVariableTotalSize += VariableSize;
> +            if (IsUserVariable (Variable)) {
> +              CommonUserVariableTotalSize += VariableSize;
> +            }
> +          }
> +        }
> +
> +        CurrPtr += VariableSize;
> +      }
> +    }
> +
> +    Variable = NextVariable;
> +  }
> +
> +  //
> +  // Install the new variable if it is not NULL.
> +  //
> +  if (NewVariable != NULL) {
> +    if (((UINTN)CurrPtr - (UINTN)ValidBuffer) + NewVariableSize >
> VariableStoreHeader->Size) {
> +      //
> +      // No enough space to store the new variable.
> +      //
> +      Status = EFI_OUT_OF_RESOURCES;
> +      goto Done;
> +    }
> +
> +    if (!IsVolatile) {
> +      if ((NewVariable->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
> == EFI_VARIABLE_HARDWARE_ERROR_RECORD) {
> +        HwErrVariableTotalSize += NewVariableSize;
> +      } else if ((NewVariable->Attributes &
> EFI_VARIABLE_HARDWARE_ERROR_RECORD) !=
> EFI_VARIABLE_HARDWARE_ERROR_RECORD) {
> +        CommonVariableTotalSize += NewVariableSize;
> +        if (IsUserVariable (NewVariable)) {
> +          CommonUserVariableTotalSize += NewVariableSize;
> +        }
> +      }
> +
> +      if ((HwErrVariableTotalSize > PcdGet32 (PcdHwErrStorageSize)) ||
> +          (CommonVariableTotalSize > mVariableModuleGlobal-
> >CommonVariableSpace) ||
> +          (CommonUserVariableTotalSize > mVariableModuleGlobal-
> >CommonMaxUserVariableSpace))
> +      {
> +        //
> +        // No enough space to store the new variable by NV or NV+HR attribute.
> +        //
> +        Status = EFI_OUT_OF_RESOURCES;
> +        goto Done;
> +      }
> +    }
> +
> +    CopyMem (CurrPtr, (UINT8 *)NewVariable, NewVariableSize);
> +    ((VARIABLE_HEADER *)CurrPtr)->State = VAR_ADDED;
> +    if (UpdatingVariable != NULL) {
> +      UpdatingPtrTrack->CurrPtr                = (VARIABLE_HEADER
> *)((UINTN)UpdatingPtrTrack->StartPtr + ((UINTN)CurrPtr -
> (UINTN)GetStartPointer ((VARIABLE_STORE_HEADER *)ValidBuffer)));
> +      UpdatingPtrTrack->InDeletedTransitionPtr = NULL;
> +    }
> +
> +    CurrPtr += NewVariableSize;
> +  }
> +
> +  if (IsVolatile || mVariableModuleGlobal->VariableGlobal.EmuNvMode) {
> +    //
> +    // If volatile/emulated non-volatile variable store, just copy valid buffer.
> +    //
> +    SetMem ((UINT8 *)(UINTN)VariableBase, VariableStoreHeader->Size, 0xff);
> +    CopyMem ((UINT8 *)(UINTN)VariableBase, ValidBuffer, (UINTN)CurrPtr -
> (UINTN)ValidBuffer);
> +    *LastVariableOffset = (UINTN)CurrPtr - (UINTN)ValidBuffer;
> +    if (!IsVolatile) {
> +      //
> +      // Emulated non-volatile variable mode.
> +      //
> +      mVariableModuleGlobal->HwErrVariableTotalSize      =
> HwErrVariableTotalSize;
> +      mVariableModuleGlobal->CommonVariableTotalSize     =
> CommonVariableTotalSize;
> +      mVariableModuleGlobal->CommonUserVariableTotalSize =
> CommonUserVariableTotalSize;
> +    }
> +
> +    Status = EFI_SUCCESS;
> +  } else {
> +    //
> +    // If non-volatile variable store, perform FTW here.
> +    //
> +    Status = FtwVariableSpace (
> +               VariableBase,
> +               (VARIABLE_STORE_HEADER *)ValidBuffer
> +               );
> +    if (!EFI_ERROR (Status)) {
> +      *LastVariableOffset                                = (UINTN)CurrPtr - (UINTN)ValidBuffer;
> +      mVariableModuleGlobal->HwErrVariableTotalSize      =
> HwErrVariableTotalSize;
> +      mVariableModuleGlobal->CommonVariableTotalSize     =
> CommonVariableTotalSize;
> +      mVariableModuleGlobal->CommonUserVariableTotalSize =
> CommonUserVariableTotalSize;
> +    } else {
> +      mVariableModuleGlobal->HwErrVariableTotalSize      = 0;
> +      mVariableModuleGlobal->CommonVariableTotalSize     = 0;
> +      mVariableModuleGlobal->CommonUserVariableTotalSize = 0;
> +      Variable                                           = GetStartPointer
> ((VARIABLE_STORE_HEADER *)(UINTN)VariableBase);
> +      while (IsValidVariableHeader (Variable, GetEndPointer
> ((VARIABLE_STORE_HEADER *)(UINTN)VariableBase), AuthFormat)) {
> +        NextVariable = GetNextVariablePtr (Variable, AuthFormat);
> +        VariableSize = (UINTN)NextVariable - (UINTN)Variable;
> +        if ((Variable->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
> == EFI_VARIABLE_HARDWARE_ERROR_RECORD) {
> +          mVariableModuleGlobal->HwErrVariableTotalSize += VariableSize;
> +        } else if ((Variable->Attributes &
> EFI_VARIABLE_HARDWARE_ERROR_RECORD) !=
> EFI_VARIABLE_HARDWARE_ERROR_RECORD) {
> +          mVariableModuleGlobal->CommonVariableTotalSize += VariableSize;
> +          if (IsUserVariable (Variable)) {
> +            mVariableModuleGlobal->CommonUserVariableTotalSize +=
> VariableSize;
> +          }
> +        }
> +
> +        Variable = NextVariable;
> +      }
> +
> +      *LastVariableOffset = (UINTN)Variable - (UINTN)VariableBase;
> +    }
> +  }
> +
> +Done:
> +  DoneStatus = EFI_SUCCESS;
> +  if (IsVolatile || mVariableModuleGlobal->VariableGlobal.EmuNvMode) {
> +    DoneStatus = SynchronizeRuntimeVariableCache (
> +                   &mVariableModuleGlobal-
> >VariableGlobal.VariableRuntimeCacheContext.VariableRuntimeVolatileCache,
> +                   0,
> +                   VariableStoreHeader->Size
> +                   );
> +    ASSERT_EFI_ERROR (DoneStatus);
> +    FreePool (ValidBuffer);
> +  } else {
> +    //
> +    // For NV variable reclaim, we use mNvVariableCache as the buffer, so copy
> the data back.
> +    //
> +    CopyMem (mNvVariableCache, (UINT8 *)(UINTN)VariableBase,
> VariableStoreHeader->Size);
> +    DoneStatus = SynchronizeRuntimeVariableCache (
> +                   &mVariableModuleGlobal-
> >VariableGlobal.VariableRuntimeCacheContext.VariableRuntimeNvCache,
> +                   0,
> +                   VariableStoreHeader->Size
> +                   );
> +    ASSERT_EFI_ERROR (DoneStatus);
> +  }
> +
> +  if (!EFI_ERROR (Status) && EFI_ERROR (DoneStatus)) {
> +    Status = DoneStatus;
> +  }
> +
> +  return Status;
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/RuntimeDxeUnitT
> est/VariableLockRequestToLockUnitTest.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/RuntimeDxeUnitT
> est/VariableLockRequestToLockUnitTest.c
> new file mode 100644
> index 000000000000..b2bcb97932ba
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/RuntimeDxeUnitT
> est/VariableLockRequestToLockUnitTest.c
> @@ -0,0 +1,607 @@
> +/** @file
> +  This is a host-based unit test for the VariableLockRequestToLock shim.
> +
> +  Copyright (c) Microsoft Corporation.
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <stdio.h>
> +#include <string.h>
> +#include <stdarg.h>
> +#include <stddef.h>
> +#include <setjmp.h>
> +#include <cmocka.h>
> +
> +#include <Uefi.h>
> +#include <Library/DebugLib.h>
> +#include <Library/BaseMemoryLib.h>
> +#include <Library/MemoryAllocationLib.h>
> +#include <Library/UnitTestLib.h>
> +#include <Library/VariablePolicyLib.h>
> +#include <Library/VariablePolicyHelperLib.h>
> +
> +#include <Protocol/VariableLock.h>
> +
> +#define UNIT_TEST_NAME     "VarPol/VarLock Shim Unit Test"
> +#define UNIT_TEST_VERSION  "1.0"
> +
> +/// === CODE UNDER TEST
> =================================================================
> ==========
> +
> +EFI_STATUS
> +EFIAPI
> +VariableLockRequestToLock (
> +  IN CONST EDKII_VARIABLE_LOCK_PROTOCOL  *This,
> +  IN       CHAR16                        *VariableName,
> +  IN       EFI_GUID                      *VendorGuid
> +  );
> +
> +/// === TEST DATA
> =================================================================
> =================
> +
> +//
> +// Test GUID 1 {F955BA2D-4A2C-480C-BFD1-3CC522610592}
> +//
> +EFI_GUID  mTestGuid1 = {
> +  0xf955ba2d, 0x4a2c, 0x480c, { 0xbf, 0xd1, 0x3c, 0xc5, 0x22, 0x61, 0x5, 0x92 }
> +};
> +
> +//
> +// Test GUID 2 {2DEA799E-5E73-43B9-870E-C945CE82AF3A}
> +//
> +EFI_GUID  mTestGuid2 = {
> +  0x2dea799e, 0x5e73, 0x43b9, { 0x87, 0xe, 0xc9, 0x45, 0xce, 0x82, 0xaf, 0x3a }
> +};
> +
> +//
> +// Test GUID 3 {698A2BFD-A616-482D-B88C-7100BD6682A9}
> +//
> +EFI_GUID  mTestGuid3 = {
> +  0x698a2bfd, 0xa616, 0x482d, { 0xb8, 0x8c, 0x71, 0x0, 0xbd, 0x66, 0x82, 0xa9 }
> +};
> +
> +#define TEST_VAR_1_NAME  L"TestVar1"
> +#define TEST_VAR_2_NAME  L"TestVar2"
> +#define TEST_VAR_3_NAME  L"TestVar3"
> +
> +#define TEST_POLICY_ATTRIBUTES_NULL  0
> +#define TEST_POLICY_MIN_SIZE_NULL    0
> +#define TEST_POLICY_MAX_SIZE_NULL    MAX_UINT32
> +
> +#define TEST_POLICY_MIN_SIZE_10   10
> +#define TEST_POLICY_MAX_SIZE_200  200
> +
> +/// === HELPER FUNCTIONS
> =================================================================
> ==========
> +
> +/**
> +  Mocked version of GetVariable, for testing.
> +
> +  @param  VariableName
> +  @param  VendorGuid
> +  @param  Attributes
> +  @param  DataSize
> +  @param  Data
> +**/
> +EFI_STATUS
> +EFIAPI
> +StubGetVariableNull (
> +  IN     CHAR16    *VariableName,
> +  IN     EFI_GUID  *VendorGuid,
> +  OUT    UINT32    *Attributes   OPTIONAL,
> +  IN OUT UINTN     *DataSize,
> +  OUT    VOID      *Data         OPTIONAL
> +  )
> +{
> +  UINT32      MockedAttr;
> +  UINTN       MockedDataSize;
> +  VOID        *MockedData;
> +  EFI_STATUS  MockedReturn;
> +
> +  check_expected_ptr (VariableName);
> +  check_expected_ptr (VendorGuid);
> +  check_expected_ptr (DataSize);
> +
> +  MockedAttr     = (UINT32)mock ();
> +  MockedDataSize = (UINTN)mock ();
> +  MockedData     = (VOID *)(UINTN)mock ();
> +  MockedReturn   = (EFI_STATUS)mock ();
> +
> +  if (Attributes != NULL) {
> +    *Attributes = MockedAttr;
> +  }
> +
> +  if ((Data != NULL) && !EFI_ERROR (MockedReturn)) {
> +    CopyMem (Data, MockedData, MockedDataSize);
> +  }
> +
> +  *DataSize = MockedDataSize;
> +
> +  return MockedReturn;
> +}
> +
> +//
> +// Anything you think might be helpful that isn't a test itself.
> +//
> +
> +/**
> +  This is a common setup function that will ensure the library is always
> +  initialized with the stubbed GetVariable.
> +
> +  Not used by all test cases, but by most.
> +
> +  @param[in]  Context  Unit test case context
> +**/
> +STATIC
> +UNIT_TEST_STATUS
> +EFIAPI
> +LibInitMocked (
> +  IN UNIT_TEST_CONTEXT  Context
> +  )
> +{
> +  return EFI_ERROR (InitVariablePolicyLib (StubGetVariableNull)) ?
> UNIT_TEST_ERROR_PREREQUISITE_NOT_MET : UNIT_TEST_PASSED;
> +}
> +
> +/**
> +  Common cleanup function to make sure that the library is always de-initialized
> +  prior to the next test case.
> +
> +  @param[in]  Context  Unit test case context
> +**/
> +STATIC
> +VOID
> +EFIAPI
> +LibCleanup (
> +  IN UNIT_TEST_CONTEXT  Context
> +  )
> +{
> +  DeinitVariablePolicyLib ();
> +}
> +
> +/// === TEST CASES
> =================================================================
> ================
> +
> +/// ===== SHIM SUITE
> ===========================================================
> +
> +/**
> +  Test Case that locks a single variable using the Variable Lock Protocol.
> +  The call is expected to succeed.
> +
> +  @param[in]  Context  Unit test case context
> +**/
> +UNIT_TEST_STATUS
> +EFIAPI
> +LockingWithoutAnyPoliciesShouldSucceed (
> +  IN UNIT_TEST_CONTEXT  Context
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  Status = VariableLockRequestToLock (NULL, TEST_VAR_1_NAME,
> &mTestGuid1);
> +  UT_ASSERT_NOT_EFI_ERROR (Status);
> +
> +  return UNIT_TEST_PASSED;
> +}
> +
> +/**
> +  Test Case that locks the same variable twice using the Variable Lock Protocol.
> +  Both calls are expected to succeed.
> +
> +  @param[in]  Context  Unit test case context
> +  **/
> +UNIT_TEST_STATUS
> +EFIAPI
> +LockingTwiceShouldSucceed (
> +  IN UNIT_TEST_CONTEXT  Context
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  Status = VariableLockRequestToLock (NULL, TEST_VAR_1_NAME,
> &mTestGuid1);
> +  UT_ASSERT_NOT_EFI_ERROR (Status);
> +
> +  Status = VariableLockRequestToLock (NULL, TEST_VAR_1_NAME,
> &mTestGuid1);
> +  UT_ASSERT_NOT_EFI_ERROR (Status);
> +
> +  return UNIT_TEST_PASSED;
> +}
> +
> +/**
> +  Test Case that locks a variable using the Variable Policy Protocol then locks
> +  the same variable using the Variable Lock Protocol.
> +  Both calls are expected to succeed.
> +
> +  @param[in]  Context  Unit test case context
> +  **/
> +UNIT_TEST_STATUS
> +EFIAPI
> +LockingALockedVariableShouldSucceed (
> +  IN UNIT_TEST_CONTEXT  Context
> +  )
> +{
> +  EFI_STATUS             Status;
> +  VARIABLE_POLICY_ENTRY  *NewEntry;
> +
> +  //
> +  // Create a variable policy that locks the variable.
> +  //
> +  Status = CreateBasicVariablePolicy (
> +             &mTestGuid1,
> +             TEST_VAR_1_NAME,
> +             TEST_POLICY_MIN_SIZE_NULL,
> +             TEST_POLICY_MAX_SIZE_200,
> +             TEST_POLICY_ATTRIBUTES_NULL,
> +             TEST_POLICY_ATTRIBUTES_NULL,
> +             VARIABLE_POLICY_TYPE_LOCK_NOW,
> +             &NewEntry
> +             );
> +  UT_ASSERT_NOT_EFI_ERROR (Status);
> +
> +  //
> +  // Register the new policy.
> +  //
> +  Status = RegisterVariablePolicy (NewEntry);
> +
> +  Status = VariableLockRequestToLock (NULL, TEST_VAR_1_NAME,
> &mTestGuid1);
> +  UT_ASSERT_NOT_EFI_ERROR (Status);
> +
> +  FreePool (NewEntry);
> +
> +  return UNIT_TEST_PASSED;
> +}
> +
> +/**
> +  Test Case that locks a variable using the Variable Policy Protocol with a
> +  policy other than LOCK_NOW then attempts to lock the same variable using
> the
> +  Variable Lock Protocol.  The call to Variable Policy is expected to succeed
> +  and the call to Variable Lock is expected to fail.
> +
> +  @param[in]  Context  Unit test case context
> +  **/
> +UNIT_TEST_STATUS
> +EFIAPI
> +LockingAnUnlockedVariableShouldFail (
> +  IN UNIT_TEST_CONTEXT  Context
> +  )
> +{
> +  EFI_STATUS             Status;
> +  VARIABLE_POLICY_ENTRY  *NewEntry;
> +
> +  // Create a variable policy that locks the variable.
> +  Status = CreateVarStateVariablePolicy (
> +             &mTestGuid1,
> +             TEST_VAR_1_NAME,
> +             TEST_POLICY_MIN_SIZE_NULL,
> +             TEST_POLICY_MAX_SIZE_200,
> +             TEST_POLICY_ATTRIBUTES_NULL,
> +             TEST_POLICY_ATTRIBUTES_NULL,
> +             &mTestGuid2,
> +             1,
> +             TEST_VAR_2_NAME,
> +             &NewEntry
> +             );
> +  UT_ASSERT_NOT_EFI_ERROR (Status);
> +
> +  // Register the new policy.
> +  Status = RegisterVariablePolicy (NewEntry);
> +
> +  // Configure the stub to not care about parameters. We're testing errors.
> +  expect_any_always (StubGetVariableNull, VariableName);
> +  expect_any_always (StubGetVariableNull, VendorGuid);
> +  expect_any_always (StubGetVariableNull, DataSize);
> +
> +  // With a policy, make sure that writes still work, since the variable doesn't
> exist.
> +  will_return (StubGetVariableNull, TEST_POLICY_ATTRIBUTES_NULL);     //
> Attributes
> +  will_return (StubGetVariableNull, 0);                               // Size
> +  will_return (StubGetVariableNull, (UINTN)NULL);                     // DataPtr
> +  will_return (StubGetVariableNull, EFI_NOT_FOUND);                   // Status
> +
> +  Status = VariableLockRequestToLock (NULL, TEST_VAR_1_NAME,
> &mTestGuid1);
> +  UT_ASSERT_TRUE (EFI_ERROR (Status));
> +
> +  FreePool (NewEntry);
> +
> +  return UNIT_TEST_PASSED;
> +}
> +
> +/**
> +  Test Case that locks a variable using the Variable Policy Protocol with a
> +  policy other than LOCK_NOW, but is currently locked.  Then attempts to lock
> +  the same variable using the Variable Lock Protocol.  The call to Variable
> +  Policy is expected to succeed and the call to Variable Lock also expected to
> +  succeed.
> +
> +  @param[in]  Context  Unit test case context
> +  **/
> +UNIT_TEST_STATUS
> +EFIAPI
> +LockingALockedVariableWithMatchingDataShouldSucceed (
> +  IN UNIT_TEST_CONTEXT  Context
> +  )
> +{
> +  EFI_STATUS             Status;
> +  VARIABLE_POLICY_ENTRY  *NewEntry;
> +  UINT8                  Data;
> +
> +  // Create a variable policy that locks the variable.
> +  Status = CreateVarStateVariablePolicy (
> +             &mTestGuid1,
> +             TEST_VAR_1_NAME,
> +             TEST_POLICY_MIN_SIZE_NULL,
> +             TEST_POLICY_MAX_SIZE_200,
> +             TEST_POLICY_ATTRIBUTES_NULL,
> +             TEST_POLICY_ATTRIBUTES_NULL,
> +             &mTestGuid2,
> +             1,
> +             TEST_VAR_2_NAME,
> +             &NewEntry
> +             );
> +  UT_ASSERT_NOT_EFI_ERROR (Status);
> +
> +  // Register the new policy.
> +  Status = RegisterVariablePolicy (NewEntry);
> +
> +  // Configure the stub to not care about parameters. We're testing errors.
> +  expect_any_always (StubGetVariableNull, VariableName);
> +  expect_any_always (StubGetVariableNull, VendorGuid);
> +  expect_any_always (StubGetVariableNull, DataSize);
> +
> +  // With a policy, make sure that writes still work, since the variable doesn't
> exist.
> +  Data = 1;
> +  will_return (StubGetVariableNull, TEST_POLICY_ATTRIBUTES_NULL);     //
> Attributes
> +  will_return (StubGetVariableNull, sizeof (Data));                   // Size
> +  will_return (StubGetVariableNull, (UINTN)&Data);                    // DataPtr
> +  will_return (StubGetVariableNull, EFI_SUCCESS);                     // Status
> +
> +  Status = VariableLockRequestToLock (NULL, TEST_VAR_1_NAME,
> &mTestGuid1);
> +  UT_ASSERT_TRUE (!EFI_ERROR (Status));
> +
> +  FreePool (NewEntry);
> +
> +  return UNIT_TEST_PASSED;
> +}
> +
> +/**
> +  Test Case that locks a variable using the Variable Policy Protocol with a
> +  policy other than LOCK_NOW, but variable data does not match.  Then
> attempts
> +  to lock the same variable using the Variable Lock Protocol.  The call to
> +  Variable Policy is expected to succeed and the call to Variable Lock is
> +  expected to fail.
> +
> +  @param[in]  Context  Unit test case context
> +  **/
> +UNIT_TEST_STATUS
> +EFIAPI
> +LockingALockedVariableWithNonMatchingDataShouldFail (
> +  IN UNIT_TEST_CONTEXT  Context
> +  )
> +{
> +  EFI_STATUS             Status;
> +  VARIABLE_POLICY_ENTRY  *NewEntry;
> +  UINT8                  Data;
> +
> +  // Create a variable policy that locks the variable.
> +  Status = CreateVarStateVariablePolicy (
> +             &mTestGuid1,
> +             TEST_VAR_1_NAME,
> +             TEST_POLICY_MIN_SIZE_NULL,
> +             TEST_POLICY_MAX_SIZE_200,
> +             TEST_POLICY_ATTRIBUTES_NULL,
> +             TEST_POLICY_ATTRIBUTES_NULL,
> +             &mTestGuid2,
> +             1,
> +             TEST_VAR_2_NAME,
> +             &NewEntry
> +             );
> +  UT_ASSERT_NOT_EFI_ERROR (Status);
> +
> +  // Register the new policy.
> +  Status = RegisterVariablePolicy (NewEntry);
> +
> +  // Configure the stub to not care about parameters. We're testing errors.
> +  expect_any_always (StubGetVariableNull, VariableName);
> +  expect_any_always (StubGetVariableNull, VendorGuid);
> +  expect_any_always (StubGetVariableNull, DataSize);
> +
> +  // With a policy, make sure that writes still work, since the variable doesn't
> exist.
> +  Data = 2;
> +  will_return (StubGetVariableNull, TEST_POLICY_ATTRIBUTES_NULL);     //
> Attributes
> +  will_return (StubGetVariableNull, sizeof (Data));                   // Size
> +  will_return (StubGetVariableNull, (UINTN)&Data);                    // DataPtr
> +  will_return (StubGetVariableNull, EFI_SUCCESS);                     // Status
> +
> +  Status = VariableLockRequestToLock (NULL, TEST_VAR_1_NAME,
> &mTestGuid1);
> +  UT_ASSERT_TRUE (EFI_ERROR (Status));
> +
> +  FreePool (NewEntry);
> +
> +  return UNIT_TEST_PASSED;
> +}
> +
> +/**
> +  Test Case that locks a variable using Variable Lock Protocol Policy Protocol
> +  then and then attempts to lock the same variable using the Variable Policy
> +  Protocol.  The call to Variable Lock is expected to succeed and the call to
> +  Variable Policy is expected to fail.
> +
> +  @param[in]  Context  Unit test case context
> +  **/
> +UNIT_TEST_STATUS
> +EFIAPI
> +SettingPolicyForALockedVariableShouldFail (
> +  IN UNIT_TEST_CONTEXT  Context
> +  )
> +{
> +  EFI_STATUS             Status;
> +  VARIABLE_POLICY_ENTRY  *NewEntry;
> +
> +  // Lock the variable.
> +  Status = VariableLockRequestToLock (NULL, TEST_VAR_1_NAME,
> &mTestGuid1);
> +  UT_ASSERT_NOT_EFI_ERROR (Status);
> +
> +  // Create a variable policy that locks the variable.
> +  Status = CreateVarStateVariablePolicy (
> +             &mTestGuid1,
> +             TEST_VAR_1_NAME,
> +             TEST_POLICY_MIN_SIZE_NULL,
> +             TEST_POLICY_MAX_SIZE_200,
> +             TEST_POLICY_ATTRIBUTES_NULL,
> +             TEST_POLICY_ATTRIBUTES_NULL,
> +             &mTestGuid2,
> +             1,
> +             TEST_VAR_2_NAME,
> +             &NewEntry
> +             );
> +  UT_ASSERT_NOT_EFI_ERROR (Status);
> +
> +  // Register the new policy.
> +  Status = RegisterVariablePolicy (NewEntry);
> +  UT_ASSERT_TRUE (EFI_ERROR (Status));
> +
> +  FreePool (NewEntry);
> +
> +  return UNIT_TEST_PASSED;
> +}
> +
> +/**
> +  Main entry point to this unit test application.
> +
> +  Sets up and runs the test suites.
> +**/
> +VOID
> +EFIAPI
> +UnitTestMain (
> +  VOID
> +  )
> +{
> +  EFI_STATUS                  Status;
> +  UNIT_TEST_FRAMEWORK_HANDLE  Framework;
> +  UNIT_TEST_SUITE_HANDLE      ShimTests;
> +
> +  Framework = NULL;
> +
> +  DEBUG ((DEBUG_INFO, "%a v%a\n", UNIT_TEST_NAME,
> UNIT_TEST_VERSION));
> +
> +  //
> +  // Start setting up the test framework for running the tests.
> +  //
> +  Status = InitUnitTestFramework (&Framework, UNIT_TEST_NAME,
> gEfiCallerBaseName, UNIT_TEST_VERSION);
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "Failed in InitUnitTestFramework. Status = %r\n",
> Status));
> +    goto EXIT;
> +  }
> +
> +  //
> +  // Add all test suites and tests.
> +  //
> +  Status = CreateUnitTestSuite (
> +             &ShimTests,
> +             Framework,
> +             "Variable Lock Shim Tests",
> +             "VarPolicy.VarLockShim",
> +             NULL,
> +             NULL
> +             );
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "Failed in CreateUnitTestSuite for ShimTests\n"));
> +    Status = EFI_OUT_OF_RESOURCES;
> +    goto EXIT;
> +  }
> +
> +  AddTestCase (
> +    ShimTests,
> +    "Locking a variable with no matching policies should always work",
> +    "EmptyPolicies",
> +    LockingWithoutAnyPoliciesShouldSucceed,
> +    LibInitMocked,
> +    LibCleanup,
> +    NULL
> +    );
> +  AddTestCase (
> +    ShimTests,
> +    "Locking a variable twice should always work",
> +    "DoubleLock",
> +    LockingTwiceShouldSucceed,
> +    LibInitMocked,
> +    LibCleanup,
> +    NULL
> +    );
> +  AddTestCase (
> +    ShimTests,
> +    "Locking a variable that's already locked by another policy should work",
> +    "LockAfterPolicy",
> +    LockingALockedVariableShouldSucceed,
> +    LibInitMocked,
> +    LibCleanup,
> +    NULL
> +    );
> +  AddTestCase (
> +    ShimTests,
> +    "Locking a variable that already has an unlocked policy should fail",
> +    "LockAfterUnlockedPolicy",
> +    LockingAnUnlockedVariableShouldFail,
> +    LibInitMocked,
> +    LibCleanup,
> +    NULL
> +    );
> +  AddTestCase (
> +    ShimTests,
> +    "Locking a variable that already has an locked policy should succeed",
> +    "LockAfterLockedPolicyMatchingData",
> +    LockingALockedVariableWithMatchingDataShouldSucceed,
> +    LibInitMocked,
> +    LibCleanup,
> +    NULL
> +    );
> +  AddTestCase (
> +    ShimTests,
> +    "Locking a variable that already has an locked policy with matching data
> should succeed",
> +    "LockAfterLockedPolicyNonMatchingData",
> +    LockingALockedVariableWithNonMatchingDataShouldFail,
> +    LibInitMocked,
> +    LibCleanup,
> +    NULL
> +    );
> +  AddTestCase (
> +    ShimTests,
> +    "Adding a policy for a variable that has previously been locked should always
> fail",
> +    "SetPolicyAfterLock",
> +    SettingPolicyForALockedVariableShouldFail,
> +    LibInitMocked,
> +    LibCleanup,
> +    NULL
> +    );
> +
> +  //
> +  // Execute the tests.
> +  //
> +  Status = RunAllTestSuites (Framework);
> +
> +EXIT:
> +  if (Framework != NULL) {
> +    FreeUnitTestFramework (Framework);
> +  }
> +
> +  return;
> +}
> +
> +///
> +/// Avoid ECC error for function name that starts with lower case letter
> +///
> +#define Main  main
> +
> +/**
> +  Standard POSIX C entry point for host based unit test execution.
> +
> +  @param[in] Argc  Number of arguments
> +  @param[in] Argv  Array of pointers to arguments
> +
> +  @retval 0      Success
> +  @retval other  Error
> +**/
> +INT32
> +Main (
> +  IN INT32  Argc,
> +  IN CHAR8  *Argv[]
> +  )
> +{
> +  UnitTestMain ();
> +  return 0;
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/SpeculationBarrie
> rDxe.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/SpeculationBarrie
> rDxe.c
> new file mode 100644
> index 000000000000..b219ea9ec074
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/SpeculationBarrie
> rDxe.c
> @@ -0,0 +1,27 @@
> +/** @file
> +  Barrier to stop speculative execution (DXE version).
> +
> +Copyright (c) 2018, Intel Corporation. All rights reserved.<BR>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include "Variable.h"
> +
> +/**
> +  This service is consumed by the variable modules to place a barrier to stop
> +  speculative execution.
> +
> +  Ensures that no later instruction will execute speculatively, until all prior
> +  instructions have completed.
> +
> +**/
> +VOID
> +VariableSpeculationBarrier (
> +  VOID
> +  )
> +{
> +  //
> +  // Do nothing.
> +  //
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/SpeculationBarrie
> rSmm.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/SpeculationBarrie
> rSmm.c
> new file mode 100644
> index 000000000000..7107c042928e
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/SpeculationBarrie
> rSmm.c
> @@ -0,0 +1,26 @@
> +/** @file
> +  Barrier to stop speculative execution (SMM version).
> +
> +Copyright (c) 2018, Intel Corporation. All rights reserved.<BR>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <Library/BaseLib.h>
> +#include "Variable.h"
> +
> +/**
> +  This service is consumed by the variable modules to place a barrier to stop
> +  speculative execution.
> +
> +  Ensures that no later instruction will execute speculatively, until all prior
> +  instructions have completed.
> +
> +**/
> +VOID
> +VariableSpeculationBarrier (
> +  VOID
> +  )
> +{
> +  SpeculationBarrier ();
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/TcgMorLockDxe.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/TcgMorLockDxe.c
> new file mode 100644
> index 000000000000..88984c31ab4f
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/TcgMorLockDxe.c
> @@ -0,0 +1,153 @@
> +/** @file
> +  TCG MOR (Memory Overwrite Request) Lock Control support (DXE version).
> +
> +  This module clears MemoryOverwriteRequestControlLock variable to indicate
> +  MOR lock control unsupported.
> +
> +Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>
> +Copyright (c) Microsoft Corporation.
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <PiDxe.h>
> +#include <Guid/MemoryOverwriteControl.h>
> +#include <IndustryStandard/MemoryOverwriteRequestControlLock.h>
> +#include <Library/DebugLib.h>
> +#include <Library/BaseLib.h>
> +#include <Library/BaseMemoryLib.h>
> +#include "Variable.h"
> +
> +#include <Protocol/VariablePolicy.h>
> +#include <Library/VariablePolicyHelperLib.h>
> +
> +/**
> +  This service is an MOR/MorLock checker handler for the SetVariable().
> +
> +  @param[in]  VariableName the name of the vendor's variable, as a
> +                           Null-Terminated Unicode String
> +  @param[in]  VendorGuid   Unify identifier for vendor.
> +  @param[in]  Attributes   Attributes bitmask to set for the variable.
> +  @param[in]  DataSize     The size in bytes of Data-Buffer.
> +  @param[in]  Data         Point to the content of the variable.
> +
> +  @retval  EFI_SUCCESS            The MOR/MorLock check pass, and Variable
> +                                  driver can store the variable data.
> +  @retval  EFI_INVALID_PARAMETER  The MOR/MorLock data or data size or
> +                                  attributes is not allowed for MOR variable.
> +  @retval  EFI_ACCESS_DENIED      The MOR/MorLock is locked.
> +  @retval  EFI_ALREADY_STARTED    The MorLock variable is handled inside this
> +                                  function. Variable driver can just return
> +                                  EFI_SUCCESS.
> +**/
> +EFI_STATUS
> +SetVariableCheckHandlerMor (
> +  IN CHAR16    *VariableName,
> +  IN EFI_GUID  *VendorGuid,
> +  IN UINT32    Attributes,
> +  IN UINTN     DataSize,
> +  IN VOID      *Data
> +  )
> +{
> +  //
> +  // Just let it pass. No need provide protection for DXE version.
> +  //
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Initialization for MOR Control Lock.
> +
> +  @retval EFI_SUCCESS     MorLock initialization success.
> +  @return Others          Some error occurs.
> +**/
> +EFI_STATUS
> +MorLockInit (
> +  VOID
> +  )
> +{
> +  //
> +  // Always clear variable to report unsupported to OS.
> +  // The reason is that the DXE version is not proper to provide *protection*.
> +  // BIOS should use SMM version variable driver to provide such capability.
> +  //
> +  VariableServiceSetVariable (
> +    MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME,
> +    &gEfiMemoryOverwriteRequestControlLockGuid,
> +    0,                                          // Attributes
> +    0,                                          // DataSize
> +    NULL                                        // Data
> +    );
> +
> +  //
> +  // The MOR variable can effectively improve platform security only when the
> +  // MorLock variable protects the MOR variable. In turn MorLock cannot be
> made
> +  // secure without SMM support in the platform firmware (see above).
> +  //
> +  // Thus, delete the MOR variable, should it exist for any reason (some OSes
> +  // are known to create MOR unintentionally, in an attempt to set it), then
> +  // also lock the MOR variable, in order to prevent other modules from
> +  // creating it.
> +  //
> +  VariableServiceSetVariable (
> +    MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME,
> +    &gEfiMemoryOverwriteControlDataGuid,
> +    0,                                      // Attributes
> +    0,                                      // DataSize
> +    NULL                                    // Data
> +    );
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Delayed initialization for MOR Control Lock at EndOfDxe.
> +
> +  This function performs any operations queued by MorLockInit().
> +**/
> +VOID
> +MorLockInitAtEndOfDxe (
> +  VOID
> +  )
> +{
> +  EFI_STATUS                      Status;
> +  EDKII_VARIABLE_POLICY_PROTOCOL  *VariablePolicy;
> +
> +  // First, we obviously need to locate the VariablePolicy protocol.
> +  Status = gBS->LocateProtocol (&gEdkiiVariablePolicyProtocolGuid, NULL,
> (VOID **)&VariablePolicy);
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "%a - Could not locate VariablePolicy
> protocol! %r\n", __FUNCTION__, Status));
> +    return;
> +  }
> +
> +  // If we're successful, go ahead and set the policies to protect the target
> variables.
> +  Status = RegisterBasicVariablePolicy (
> +             VariablePolicy,
> +             &gEfiMemoryOverwriteRequestControlLockGuid,
> +             MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME,
> +             VARIABLE_POLICY_NO_MIN_SIZE,
> +             VARIABLE_POLICY_NO_MAX_SIZE,
> +             VARIABLE_POLICY_NO_MUST_ATTR,
> +             VARIABLE_POLICY_NO_CANT_ATTR,
> +             VARIABLE_POLICY_TYPE_LOCK_NOW
> +             );
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "%a - Could not lock variable %s! %r\n",
> __FUNCTION__, MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME,
> Status));
> +  }
> +
> +  Status = RegisterBasicVariablePolicy (
> +             VariablePolicy,
> +             &gEfiMemoryOverwriteControlDataGuid,
> +             MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME,
> +             VARIABLE_POLICY_NO_MIN_SIZE,
> +             VARIABLE_POLICY_NO_MAX_SIZE,
> +             VARIABLE_POLICY_NO_MUST_ATTR,
> +             VARIABLE_POLICY_NO_CANT_ATTR,
> +             VARIABLE_POLICY_TYPE_LOCK_NOW
> +             );
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "%a - Could not lock variable %s! %r\n",
> __FUNCTION__, MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME, Status));
> +  }
> +
> +  return;
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/TcgMorLockSmm.
> c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/TcgMorLockSmm.
> c
> new file mode 100644
> index 000000000000..296afd2ec414
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/TcgMorLockSmm.
> c
> @@ -0,0 +1,569 @@
> +/** @file
> +  TCG MOR (Memory Overwrite Request) Lock Control support (SMM version).
> +
> +  This module initilizes MemoryOverwriteRequestControlLock variable.
> +  This module adds Variable Hook and check
> MemoryOverwriteRequestControlLock.
> +
> +Copyright (c) 2016 - 2018, Intel Corporation. All rights reserved.<BR>
> +Copyright (c) Microsoft Corporation.
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <PiDxe.h>
> +#include <Guid/MemoryOverwriteControl.h>
> +#include <IndustryStandard/MemoryOverwriteRequestControlLock.h>
> +#include <Library/DebugLib.h>
> +#include <Library/BaseLib.h>
> +#include <Library/BaseMemoryLib.h>
> +#include "Variable.h"
> +
> +#include <Protocol/VariablePolicy.h>
> +#include <Library/VariablePolicyHelperLib.h>
> +#include <Library/VariablePolicyLib.h>
> +
> +typedef struct {
> +  CHAR16      *VariableName;
> +  EFI_GUID    *VendorGuid;
> +} VARIABLE_TYPE;
> +
> +VARIABLE_TYPE  mMorVariableType[] = {
> +  { MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME,
> &gEfiMemoryOverwriteControlDataGuid        },
> +  { MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME,
> &gEfiMemoryOverwriteRequestControlLockGuid },
> +};
> +
> +BOOLEAN  mMorPassThru = FALSE;
> +
> +#define MOR_LOCK_DATA_UNLOCKED            0x0
> +#define MOR_LOCK_DATA_LOCKED_WITHOUT_KEY  0x1
> +#define MOR_LOCK_DATA_LOCKED_WITH_KEY     0x2
> +
> +#define MOR_LOCK_V1_SIZE      1
> +#define MOR_LOCK_V2_KEY_SIZE  8
> +
> +typedef enum {
> +  MorLockStateUnlocked = 0,
> +  MorLockStateLocked   = 1,
> +} MOR_LOCK_STATE;
> +
> +BOOLEAN         mMorLockInitializationRequired = FALSE;
> +UINT8           mMorLockKey[MOR_LOCK_V2_KEY_SIZE];
> +BOOLEAN         mMorLockKeyEmpty = TRUE;
> +BOOLEAN         mMorLockPassThru = FALSE;
> +MOR_LOCK_STATE  mMorLockState    = MorLockStateUnlocked;
> +
> +/**
> +  Returns if this is MOR related variable.
> +
> +  @param  VariableName the name of the vendor's variable, it's a Null-
> Terminated Unicode String
> +  @param  VendorGuid   Unify identifier for vendor.
> +
> +  @retval  TRUE            The variable is MOR related.
> +  @retval  FALSE           The variable is NOT MOR related.
> +**/
> +BOOLEAN
> +IsAnyMorVariable (
> +  IN CHAR16    *VariableName,
> +  IN EFI_GUID  *VendorGuid
> +  )
> +{
> +  UINTN  Index;
> +
> +  for (Index = 0; Index < sizeof (mMorVariableType)/sizeof
> (mMorVariableType[0]); Index++) {
> +    if ((StrCmp (VariableName, mMorVariableType[Index].VariableName) == 0)
> &&
> +        (CompareGuid (VendorGuid, mMorVariableType[Index].VendorGuid)))
> +    {
> +      return TRUE;
> +    }
> +  }
> +
> +  return FALSE;
> +}
> +
> +/**
> +  Returns if this is MOR lock variable.
> +
> +  @param  VariableName the name of the vendor's variable, it's a Null-
> Terminated Unicode String
> +  @param  VendorGuid   Unify identifier for vendor.
> +
> +  @retval  TRUE            The variable is MOR lock variable.
> +  @retval  FALSE           The variable is NOT MOR lock variable.
> +**/
> +BOOLEAN
> +IsMorLockVariable (
> +  IN CHAR16    *VariableName,
> +  IN EFI_GUID  *VendorGuid
> +  )
> +{
> +  if ((StrCmp (VariableName,
> MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME) == 0) &&
> +      (CompareGuid (VendorGuid,
> &gEfiMemoryOverwriteRequestControlLockGuid)))
> +  {
> +    return TRUE;
> +  }
> +
> +  return FALSE;
> +}
> +
> +/**
> +  Set MOR lock variable.
> +
> +  @param  Data         MOR Lock variable data.
> +
> +  @retval  EFI_SUCCESS            The firmware has successfully stored the variable
> and its data as
> +                                  defined by the Attributes.
> +  @retval  EFI_INVALID_PARAMETER  An invalid combination of attribute bits
> was supplied, or the
> +                                  DataSize exceeds the maximum allowed.
> +  @retval  EFI_INVALID_PARAMETER  VariableName is an empty Unicode string.
> +  @retval  EFI_OUT_OF_RESOURCES   Not enough storage is available to hold
> the variable and its data.
> +  @retval  EFI_DEVICE_ERROR       The variable could not be saved due to a
> hardware failure.
> +  @retval  EFI_WRITE_PROTECTED    The variable in question is read-only.
> +  @retval  EFI_WRITE_PROTECTED    The variable in question cannot be deleted.
> +  @retval  EFI_SECURITY_VIOLATION The variable could not be written due to
> EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS
> +                                  set but the AuthInfo does NOT pass the validation check
> carried
> +                                  out by the firmware.
> +  @retval  EFI_NOT_FOUND          The variable trying to be updated or deleted
> was not found.
> +**/
> +EFI_STATUS
> +SetMorLockVariable (
> +  IN UINT8  Data
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  mMorLockPassThru = TRUE;
> +  Status           = VariableServiceSetVariable (
> +                       MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME,
> +                       &gEfiMemoryOverwriteRequestControlLockGuid,
> +                       EFI_VARIABLE_NON_VOLATILE |
> EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
> +                       sizeof (Data),
> +                       &Data
> +                       );
> +  mMorLockPassThru = FALSE;
> +  return Status;
> +}
> +
> +/**
> +  This service is an MorLock checker handler for the SetVariable().
> +
> +  @param  VariableName the name of the vendor's variable, as a
> +                       Null-Terminated Unicode String
> +  @param  VendorGuid   Unify identifier for vendor.
> +  @param  Attributes   Point to memory location to return the attributes of
> variable. If the point
> +                       is NULL, the parameter would be ignored.
> +  @param  DataSize     The size in bytes of Data-Buffer.
> +  @param  Data         Point to the content of the variable.
> +
> +  @retval  EFI_SUCCESS            The MorLock check pass, and Variable driver can
> store the variable data.
> +  @retval  EFI_INVALID_PARAMETER  The MorLock data or data size or
> attributes is not allowed.
> +  @retval  EFI_ACCESS_DENIED      The MorLock is locked.
> +  @retval  EFI_WRITE_PROTECTED    The MorLock deletion is not allowed.
> +  @retval  EFI_ALREADY_STARTED    The MorLock variable is handled inside this
> function.
> +                                  Variable driver can just return EFI_SUCCESS.
> +**/
> +EFI_STATUS
> +SetVariableCheckHandlerMorLock (
> +  IN CHAR16    *VariableName,
> +  IN EFI_GUID  *VendorGuid,
> +  IN UINT32    Attributes,
> +  IN UINTN     DataSize,
> +  IN VOID      *Data
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  //
> +  // Basic Check
> +  //
> +  if ((Attributes == 0) || (DataSize == 0) || (Data == NULL)) {
> +    //
> +    // Permit deletion for passthru request, deny it otherwise.
> +    //
> +    return mMorLockPassThru ? EFI_SUCCESS : EFI_WRITE_PROTECTED;
> +  }
> +
> +  if ((Attributes != (EFI_VARIABLE_NON_VOLATILE |
> EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS)) ||
> +      ((DataSize != MOR_LOCK_V1_SIZE) && (DataSize !=
> MOR_LOCK_V2_KEY_SIZE)))
> +  {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  //
> +  // Do not check if the request is passthru.
> +  //
> +  if (mMorLockPassThru) {
> +    return EFI_SUCCESS;
> +  }
> +
> +  if (mMorLockState == MorLockStateUnlocked) {
> +    //
> +    // In Unlocked State
> +    //
> +    if (DataSize == MOR_LOCK_V1_SIZE) {
> +      //
> +      // V1 - lock permanently
> +      //
> +      if (*(UINT8 *)Data == MOR_LOCK_DATA_UNLOCKED) {
> +        //
> +        // Unlock
> +        //
> +        Status = SetMorLockVariable (MOR_LOCK_DATA_UNLOCKED);
> +        if (!EFI_ERROR (Status)) {
> +          //
> +          // return EFI_ALREADY_STARTED to skip variable set.
> +          //
> +          return EFI_ALREADY_STARTED;
> +        } else {
> +          //
> +          // SetVar fail
> +          //
> +          return Status;
> +        }
> +      } else if (*(UINT8 *)Data == MOR_LOCK_DATA_LOCKED_WITHOUT_KEY) {
> +        //
> +        // Lock without key
> +        //
> +        Status = SetMorLockVariable (MOR_LOCK_DATA_LOCKED_WITHOUT_KEY);
> +        if (!EFI_ERROR (Status)) {
> +          //
> +          // Lock success
> +          //
> +          mMorLockState = MorLockStateLocked;
> +          //
> +          // return EFI_ALREADY_STARTED to skip variable set.
> +          //
> +          return EFI_ALREADY_STARTED;
> +        } else {
> +          //
> +          // SetVar fail
> +          //
> +          return Status;
> +        }
> +      } else {
> +        return EFI_INVALID_PARAMETER;
> +      }
> +    } else if (DataSize == MOR_LOCK_V2_KEY_SIZE) {
> +      //
> +      // V2 lock and provision the key
> +      //
> +
> +      //
> +      // Need set here because the data value on flash is different
> +      //
> +      Status = SetMorLockVariable (MOR_LOCK_DATA_LOCKED_WITH_KEY);
> +      if (EFI_ERROR (Status)) {
> +        //
> +        // SetVar fail, do not provision the key
> +        //
> +        return Status;
> +      } else {
> +        //
> +        // Lock success, provision the key
> +        //
> +        mMorLockKeyEmpty = FALSE;
> +        CopyMem (mMorLockKey, Data, MOR_LOCK_V2_KEY_SIZE);
> +        mMorLockState = MorLockStateLocked;
> +        //
> +        // return EFI_ALREADY_STARTED to skip variable set.
> +        //
> +        return EFI_ALREADY_STARTED;
> +      }
> +    } else {
> +      ASSERT (FALSE);
> +      return EFI_OUT_OF_RESOURCES;
> +    }
> +  } else {
> +    //
> +    // In Locked State
> +    //
> +    if (mMorLockKeyEmpty || (DataSize != MOR_LOCK_V2_KEY_SIZE)) {
> +      return EFI_ACCESS_DENIED;
> +    }
> +
> +    if ((CompareMem (Data, mMorLockKey, MOR_LOCK_V2_KEY_SIZE) == 0)) {
> +      //
> +      // Key match - unlock
> +      //
> +
> +      //
> +      // Need set here because the data value on flash is different
> +      //
> +      Status = SetMorLockVariable (MOR_LOCK_DATA_UNLOCKED);
> +      if (EFI_ERROR (Status)) {
> +        //
> +        // SetVar fail
> +        //
> +        return Status;
> +      } else {
> +        //
> +        // Unlock Success
> +        //
> +        mMorLockState    = MorLockStateUnlocked;
> +        mMorLockKeyEmpty = TRUE;
> +        ZeroMem (mMorLockKey, sizeof (mMorLockKey));
> +        //
> +        // return EFI_ALREADY_STARTED to skip variable set.
> +        //
> +        return EFI_ALREADY_STARTED;
> +      }
> +    } else {
> +      //
> +      // Key mismatch - Prevent Dictionary Attack
> +      //
> +      mMorLockState    = MorLockStateLocked;
> +      mMorLockKeyEmpty = TRUE;
> +      ZeroMem (mMorLockKey, sizeof (mMorLockKey));
> +      return EFI_ACCESS_DENIED;
> +    }
> +  }
> +}
> +
> +/**
> +  This service is an MOR/MorLock checker handler for the SetVariable().
> +
> +  @param[in]  VariableName the name of the vendor's variable, as a
> +                           Null-Terminated Unicode String
> +  @param[in]  VendorGuid   Unify identifier for vendor.
> +  @param[in]  Attributes   Attributes bitmask to set for the variable.
> +  @param[in]  DataSize     The size in bytes of Data-Buffer.
> +  @param[in]  Data         Point to the content of the variable.
> +
> +  @retval  EFI_SUCCESS            The MOR/MorLock check pass, and Variable
> +                                  driver can store the variable data.
> +  @retval  EFI_INVALID_PARAMETER  The MOR/MorLock data or data size or
> +                                  attributes is not allowed for MOR variable.
> +  @retval  EFI_ACCESS_DENIED      The MOR/MorLock is locked.
> +  @retval  EFI_ALREADY_STARTED    The MorLock variable is handled inside this
> +                                  function. Variable driver can just return
> +                                  EFI_SUCCESS.
> +**/
> +EFI_STATUS
> +SetVariableCheckHandlerMor (
> +  IN CHAR16    *VariableName,
> +  IN EFI_GUID  *VendorGuid,
> +  IN UINT32    Attributes,
> +  IN UINTN     DataSize,
> +  IN VOID      *Data
> +  )
> +{
> +  //
> +  // do not handle non-MOR variable
> +  //
> +  if (!IsAnyMorVariable (VariableName, VendorGuid)) {
> +    return EFI_SUCCESS;
> +  }
> +
> +  // Permit deletion when policy is disabled.
> +  if (!IsVariablePolicyEnabled () && ((Attributes == 0) || (DataSize == 0))) {
> +    return EFI_SUCCESS;
> +  }
> +
> +  //
> +  // MorLock variable
> +  //
> +  if (IsMorLockVariable (VariableName, VendorGuid)) {
> +    return SetVariableCheckHandlerMorLock (
> +             VariableName,
> +             VendorGuid,
> +             Attributes,
> +             DataSize,
> +             Data
> +             );
> +  }
> +
> +  //
> +  // Mor Variable
> +  //
> +
> +  //
> +  // Permit deletion for passthru request.
> +  //
> +  if (((Attributes == 0) || (DataSize == 0)) && mMorPassThru) {
> +    return EFI_SUCCESS;
> +  }
> +
> +  //
> +  // Basic Check
> +  //
> +  if ((Attributes != (EFI_VARIABLE_NON_VOLATILE |
> EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS)) ||
> +      (DataSize != sizeof (UINT8)) ||
> +      (Data == NULL))
> +  {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (mMorLockState == MorLockStateLocked) {
> +    //
> +    // If lock, deny access
> +    //
> +    return EFI_ACCESS_DENIED;
> +  }
> +
> +  //
> +  // grant access
> +  //
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Initialization for MOR Control Lock.
> +
> +  @retval EFI_SUCCESS     MorLock initialization success.
> +  @return Others          Some error occurs.
> +**/
> +EFI_STATUS
> +MorLockInit (
> +  VOID
> +  )
> +{
> +  mMorLockInitializationRequired = TRUE;
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Delayed initialization for MOR Control Lock at EndOfDxe.
> +
> +  This function performs any operations queued by MorLockInit().
> +**/
> +VOID
> +MorLockInitAtEndOfDxe (
> +  VOID
> +  )
> +{
> +  UINTN                  MorSize;
> +  EFI_STATUS             MorStatus;
> +  EFI_STATUS             Status;
> +  VARIABLE_POLICY_ENTRY  *NewPolicy;
> +
> +  if (!mMorLockInitializationRequired) {
> +    //
> +    // The EFI_SMM_FAULT_TOLERANT_WRITE_PROTOCOL has never been
> installed, thus
> +    // the variable write service is unavailable. This should never happen.
> +    //
> +    ASSERT (FALSE);
> +    return;
> +  }
> +
> +  //
> +  // Check if the MOR variable exists.
> +  //
> +  MorSize   = 0;
> +  MorStatus = VariableServiceGetVariable (
> +                MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME,
> +                &gEfiMemoryOverwriteControlDataGuid,
> +                NULL,                                   // Attributes
> +                &MorSize,
> +                NULL                                    // Data
> +                );
> +  //
> +  // We provided a zero-sized buffer, so the above call can never succeed.
> +  //
> +  ASSERT (EFI_ERROR (MorStatus));
> +
> +  if (MorStatus == EFI_BUFFER_TOO_SMALL) {
> +    //
> +    // The MOR variable exists.
> +    //
> +    // Some OSes don't follow the TCG's Platform Reset Attack Mitigation spec
> +    // in that the OS should never create the MOR variable, only read and write
> +    // it -- these OSes (unintentionally) create MOR if the platform firmware
> +    // does not produce it. Whether this is the case (from the last OS boot)
> +    // can be deduced from the absence of the TCG / TCG2 protocols, as edk2's
> +    // MOR implementation depends on (one of) those protocols.
> +    //
> +    if (VariableHaveTcgProtocols ()) {
> +      //
> +      // The MOR variable originates from the platform firmware; set the MOR
> +      // Control Lock variable to report the locking capability to the OS.
> +      //
> +      SetMorLockVariable (0);
> +      return;
> +    }
> +
> +    //
> +    // The MOR variable's origin is inexplicable; delete it.
> +    //
> +    DEBUG ((
> +      DEBUG_WARN,
> +      "%a: deleting unexpected / unsupported variable %g:%s\n",
> +      __FUNCTION__,
> +      &gEfiMemoryOverwriteControlDataGuid,
> +      MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME
> +      ));
> +
> +    mMorPassThru = TRUE;
> +    VariableServiceSetVariable (
> +      MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME,
> +      &gEfiMemoryOverwriteControlDataGuid,
> +      0,                                      // Attributes
> +      0,                                      // DataSize
> +      NULL                                    // Data
> +      );
> +    mMorPassThru = FALSE;
> +  }
> +
> +  //
> +  // The MOR variable is absent; the platform firmware does not support it.
> +  // Lock the variable so that no other module may create it.
> +  //
> +  NewPolicy = NULL;
> +  Status    = CreateBasicVariablePolicy (
> +                &gEfiMemoryOverwriteControlDataGuid,
> +                MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME,
> +                VARIABLE_POLICY_NO_MIN_SIZE,
> +                VARIABLE_POLICY_NO_MAX_SIZE,
> +                VARIABLE_POLICY_NO_MUST_ATTR,
> +                VARIABLE_POLICY_NO_CANT_ATTR,
> +                VARIABLE_POLICY_TYPE_LOCK_NOW,
> +                &NewPolicy
> +                );
> +  if (!EFI_ERROR (Status)) {
> +    Status = RegisterVariablePolicy (NewPolicy);
> +  }
> +
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "%a - Failed to lock variable %s! %r\n",
> __FUNCTION__, MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME, Status));
> +    ASSERT_EFI_ERROR (Status);
> +  }
> +
> +  if (NewPolicy != NULL) {
> +    FreePool (NewPolicy);
> +  }
> +
> +  //
> +  // Delete the MOR Control Lock variable too (should it exists for some
> +  // reason) and prevent other modules from creating it.
> +  //
> +  mMorLockPassThru = TRUE;
> +  VariableServiceSetVariable (
> +    MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME,
> +    &gEfiMemoryOverwriteRequestControlLockGuid,
> +    0,                                          // Attributes
> +    0,                                          // DataSize
> +    NULL                                        // Data
> +    );
> +  mMorLockPassThru = FALSE;
> +
> +  NewPolicy = NULL;
> +  Status    = CreateBasicVariablePolicy (
> +                &gEfiMemoryOverwriteRequestControlLockGuid,
> +                MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME,
> +                VARIABLE_POLICY_NO_MIN_SIZE,
> +                VARIABLE_POLICY_NO_MAX_SIZE,
> +                VARIABLE_POLICY_NO_MUST_ATTR,
> +                VARIABLE_POLICY_NO_CANT_ATTR,
> +                VARIABLE_POLICY_TYPE_LOCK_NOW,
> +                &NewPolicy
> +                );
> +  if (!EFI_ERROR (Status)) {
> +    Status = RegisterVariablePolicy (NewPolicy);
> +  }
> +
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "%a - Failed to lock variable %s! %r\n",
> __FUNCTION__, MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME,
> Status));
> +    ASSERT_EFI_ERROR (Status);
> +  }
> +
> +  if (NewPolicy != NULL) {
> +    FreePool (NewPolicy);
> +  }
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VarCheck.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VarCheck.c
> new file mode 100644
> index 000000000000..a94b0b02ec15
> --- /dev/null
> +++ b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VarCheck.c
> @@ -0,0 +1,101 @@
> +/** @file
> +  Implementation functions and structures for var check protocol
> +  and variable lock protocol based on VarCheckLib.
> +
> +Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
> +Copyright (c) Microsoft Corporation.
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include "Variable.h"
> +
> +/**
> +  Register SetVariable check handler.
> +
> +  @param[in] Handler            Pointer to check handler.
> +
> +  @retval EFI_SUCCESS           The SetVariable check handler was registered
> successfully.
> +  @retval EFI_INVALID_PARAMETER Handler is NULL.
> +  @retval EFI_ACCESS_DENIED     EFI_END_OF_DXE_EVENT_GROUP_GUID or
> EFI_EVENT_GROUP_READY_TO_BOOT has
> +                                already been signaled.
> +  @retval EFI_OUT_OF_RESOURCES  There is not enough resource for the
> SetVariable check handler register request.
> +  @retval EFI_UNSUPPORTED       This interface is not implemented.
> +                                For example, it is unsupported in VarCheck protocol if both
> VarCheck and SmmVarCheck protocols are present.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VarCheckRegisterSetVariableCheckHandler (
> +  IN VAR_CHECK_SET_VARIABLE_CHECK_HANDLER  Handler
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  AcquireLockOnlyAtBootTime (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock);
> +  Status = VarCheckLibRegisterSetVariableCheckHandler (Handler);
> +  ReleaseLockOnlyAtBootTime (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock);
> +
> +  return Status;
> +}
> +
> +/**
> +  Variable property set.
> +
> +  @param[in] Name               Pointer to the variable name.
> +  @param[in] Guid               Pointer to the vendor GUID.
> +  @param[in] VariableProperty   Pointer to the input variable property.
> +
> +  @retval EFI_SUCCESS           The property of variable specified by the Name
> and Guid was set successfully.
> +  @retval EFI_INVALID_PARAMETER Name, Guid or VariableProperty is NULL,
> or Name is an empty string,
> +                                or the fields of VariableProperty are not valid.
> +  @retval EFI_ACCESS_DENIED     EFI_END_OF_DXE_EVENT_GROUP_GUID or
> EFI_EVENT_GROUP_READY_TO_BOOT has
> +                                already been signaled.
> +  @retval EFI_OUT_OF_RESOURCES  There is not enough resource for the
> variable property set request.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VarCheckVariablePropertySet (
> +  IN CHAR16                       *Name,
> +  IN EFI_GUID                     *Guid,
> +  IN VAR_CHECK_VARIABLE_PROPERTY  *VariableProperty
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  AcquireLockOnlyAtBootTime (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock);
> +  Status = VarCheckLibVariablePropertySet (Name, Guid, VariableProperty);
> +  ReleaseLockOnlyAtBootTime (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock);
> +
> +  return Status;
> +}
> +
> +/**
> +  Variable property get.
> +
> +  @param[in]  Name              Pointer to the variable name.
> +  @param[in]  Guid              Pointer to the vendor GUID.
> +  @param[out] VariableProperty  Pointer to the output variable property.
> +
> +  @retval EFI_SUCCESS           The property of variable specified by the Name
> and Guid was got successfully.
> +  @retval EFI_INVALID_PARAMETER Name, Guid or VariableProperty is NULL,
> or Name is an empty string.
> +  @retval EFI_NOT_FOUND         The property of variable specified by the Name
> and Guid was not found.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VarCheckVariablePropertyGet (
> +  IN CHAR16                        *Name,
> +  IN EFI_GUID                      *Guid,
> +  OUT VAR_CHECK_VARIABLE_PROPERTY  *VariableProperty
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  AcquireLockOnlyAtBootTime (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock);
> +  Status = VarCheckLibVariablePropertyGet (Name, Guid, VariableProperty);
> +  ReleaseLockOnlyAtBootTime (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock);
> +
> +  return Status;
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/Variable.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/Variable.c
> new file mode 100644
> index 000000000000..19b432b772d7
> --- /dev/null
> +++ b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/Variable.c
> @@ -0,0 +1,4037 @@
> +/** @file
> +  The common variable operation routines shared by DXE_RUNTIME variable
> +  module and DXE_SMM variable module.
> +
> +  Caution: This module requires additional review when modified.
> +  This driver will have external input - variable data. They may be input in SMM
> mode.
> +  This external input must be validated carefully to avoid security issue like
> +  buffer overflow, integer overflow.
> +
> +  VariableServiceGetNextVariableName () and
> VariableServiceQueryVariableInfo() are external API.
> +  They need check input parameter.
> +
> +  VariableServiceGetVariable() and VariableServiceSetVariable() are external API
> +  to receive datasize and data buffer. The size should be checked carefully.
> +
> +  VariableServiceSetVariable() should also check authenticate data to avoid
> buffer overflow,
> +  integer overflow. It should also check attribute to avoid authentication bypass.
> +
> +Copyright (c) 2006 - 2022, Intel Corporation. All rights reserved.<BR>
> +(C) Copyright 2015-2018 Hewlett Packard Enterprise Development LP<BR>
> +Copyright (c) Microsoft Corporation.<BR>
> +Copyright (c) 2022, ARM Limited. All rights reserved.<BR>
> +
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include "Variable.h"
> +#include "VariableNonVolatile.h"
> +#include "VariableParsing.h"
> +#include "VariableRuntimeCache.h"
> +
> +VARIABLE_MODULE_GLOBAL  *mVariableModuleGlobal = NULL;
> +
> +///
> +/// Define a memory cache that improves the search performance for a
> variable.
> +/// For EmuNvMode == TRUE, it will be equal to NonVolatileVariableBase.
> +///
> +VARIABLE_STORE_HEADER  *mNvVariableCache = NULL;
> +
> +///
> +/// Memory cache of Fv Header.
> +///
> +EFI_FIRMWARE_VOLUME_HEADER  *mNvFvHeaderCache = NULL;
> +
> +///
> +/// The memory entry used for variable statistics data.
> +///
> +VARIABLE_INFO_ENTRY  *gVariableInfo = NULL;
> +
> +///
> +/// The flag to indicate whether the platform has left the DXE phase of
> execution.
> +///
> +BOOLEAN  mEndOfDxe = FALSE;
> +
> +///
> +/// It indicates the var check request source.
> +/// In the implementation, DXE is regarded as untrusted, and SMM is trusted.
> +///
> +VAR_CHECK_REQUEST_SOURCE  mRequestSource = VarCheckFromUntrusted;
> +
> +//
> +// It will record the current boot error flag before EndOfDxe.
> +//
> +VAR_ERROR_FLAG  mCurrentBootVarErrFlag = VAR_ERROR_FLAG_NO_ERROR;
> +
> +VARIABLE_ENTRY_PROPERTY  mVariableEntryProperty[] = {
> +  {
> +    &gEdkiiVarErrorFlagGuid,
> +    VAR_ERROR_FLAG_NAME,
> +    {
> +      VAR_CHECK_VARIABLE_PROPERTY_REVISION,
> +      VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY,
> +      VARIABLE_ATTRIBUTE_NV_BS_RT,
> +      sizeof (VAR_ERROR_FLAG),
> +      sizeof (VAR_ERROR_FLAG)
> +    }
> +  },
> +};
> +
> +AUTH_VAR_LIB_CONTEXT_IN  mAuthContextIn = {
> +  AUTH_VAR_LIB_CONTEXT_IN_STRUCT_VERSION,
> +  //
> +  // StructSize, TO BE FILLED
> +  //
> +  0,
> +  //
> +  // MaxAuthVariableSize, TO BE FILLED
> +  //
> +  0,
> +  VariableExLibFindVariable,
> +  VariableExLibFindNextVariable,
> +  VariableExLibUpdateVariable,
> +  VariableExLibGetScratchBuffer,
> +  VariableExLibCheckRemainingSpaceForConsistency,
> +  VariableExLibAtRuntime,
> +};
> +
> +AUTH_VAR_LIB_CONTEXT_OUT  mAuthContextOut;
> +
> +/**
> +
> +  This function writes data to the FWH at the correct LBA even if the LBAs
> +  are fragmented.
> +
> +  @param Global                  Pointer to VARAIBLE_GLOBAL structure.
> +  @param Volatile                Point out the Variable is Volatile or Non-Volatile.
> +  @param SetByIndex              TRUE if target pointer is given as index.
> +                                 FALSE if target pointer is absolute.
> +  @param Fvb                     Pointer to the writable FVB protocol.
> +  @param DataPtrIndex            Pointer to the Data from the end of
> VARIABLE_STORE_HEADER
> +                                 structure.
> +  @param DataSize                Size of data to be written.
> +  @param Buffer                  Pointer to the buffer from which data is written.
> +
> +  @retval EFI_INVALID_PARAMETER  Parameters not valid.
> +  @retval EFI_UNSUPPORTED        Fvb is a NULL for Non-Volatile variable
> update.
> +  @retval EFI_OUT_OF_RESOURCES   The remaining size is not enough.
> +  @retval EFI_SUCCESS            Variable store successfully updated.
> +
> +**/
> +EFI_STATUS
> +UpdateVariableStore (
> +  IN  VARIABLE_GLOBAL                     *Global,
> +  IN  BOOLEAN                             Volatile,
> +  IN  BOOLEAN                             SetByIndex,
> +  IN  EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  *Fvb,
> +  IN  UINTN                               DataPtrIndex,
> +  IN  UINT32                              DataSize,
> +  IN  UINT8                               *Buffer
> +  )
> +{
> +  EFI_FV_BLOCK_MAP_ENTRY  *PtrBlockMapEntry;
> +  UINTN                   BlockIndex2;
> +  UINTN                   LinearOffset;
> +  UINTN                   CurrWriteSize;
> +  UINTN                   CurrWritePtr;
> +  UINT8                   *CurrBuffer;
> +  EFI_LBA                 LbaNumber;
> +  UINTN                   Size;
> +  VARIABLE_STORE_HEADER   *VolatileBase;
> +  EFI_PHYSICAL_ADDRESS    FvVolHdr;
> +  EFI_PHYSICAL_ADDRESS    DataPtr;
> +  EFI_STATUS              Status;
> +
> +  FvVolHdr = 0;
> +  DataPtr  = DataPtrIndex;
> +
> +  //
> +  // Check if the Data is Volatile.
> +  //
> +  if (!Volatile && !mVariableModuleGlobal->VariableGlobal.EmuNvMode) {
> +    if (Fvb == NULL) {
> +      return EFI_UNSUPPORTED;
> +    }
> +
> +    Status = Fvb->GetPhysicalAddress (Fvb, &FvVolHdr);
> +    ASSERT_EFI_ERROR (Status);
> +
> +    //
> +    // Data Pointer should point to the actual Address where data is to be
> +    // written.
> +    //
> +    if (SetByIndex) {
> +      DataPtr += mVariableModuleGlobal-
> >VariableGlobal.NonVolatileVariableBase;
> +    }
> +
> +    if ((DataPtr + DataSize) > (FvVolHdr + mNvFvHeaderCache->FvLength)) {
> +      return EFI_OUT_OF_RESOURCES;
> +    }
> +  } else {
> +    //
> +    // Data Pointer should point to the actual Address where data is to be
> +    // written.
> +    //
> +    if (Volatile) {
> +      VolatileBase = (VARIABLE_STORE_HEADER
> *)((UINTN)mVariableModuleGlobal->VariableGlobal.VolatileVariableBase);
> +      if (SetByIndex) {
> +        DataPtr += mVariableModuleGlobal->VariableGlobal.VolatileVariableBase;
> +      }
> +
> +      if ((DataPtr + DataSize) > ((UINTN)VolatileBase + VolatileBase->Size)) {
> +        return EFI_OUT_OF_RESOURCES;
> +      }
> +    } else {
> +      //
> +      // Emulated non-volatile variable mode.
> +      //
> +      if (SetByIndex) {
> +        DataPtr += (UINTN)mNvVariableCache;
> +      }
> +
> +      if ((DataPtr + DataSize) > ((UINTN)mNvVariableCache + mNvVariableCache-
> >Size)) {
> +        return EFI_OUT_OF_RESOURCES;
> +      }
> +    }
> +
> +    //
> +    // If Volatile/Emulated Non-volatile Variable just do a simple mem copy.
> +    //
> +    CopyMem ((UINT8 *)(UINTN)DataPtr, Buffer, DataSize);
> +    return EFI_SUCCESS;
> +  }
> +
> +  //
> +  // If we are here we are dealing with Non-Volatile Variables.
> +  //
> +  LinearOffset  = (UINTN)FvVolHdr;
> +  CurrWritePtr  = (UINTN)DataPtr;
> +  CurrWriteSize = DataSize;
> +  CurrBuffer    = Buffer;
> +  LbaNumber     = 0;
> +
> +  if (CurrWritePtr < LinearOffset) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  for (PtrBlockMapEntry = mNvFvHeaderCache->BlockMap; PtrBlockMapEntry-
> >NumBlocks != 0; PtrBlockMapEntry++) {
> +    for (BlockIndex2 = 0; BlockIndex2 < PtrBlockMapEntry->NumBlocks;
> BlockIndex2++) {
> +      //
> +      // Check to see if the Variable Writes are spanning through multiple
> +      // blocks.
> +      //
> +      if ((CurrWritePtr >= LinearOffset) && (CurrWritePtr < LinearOffset +
> PtrBlockMapEntry->Length)) {
> +        if ((CurrWritePtr + CurrWriteSize) <= (LinearOffset + PtrBlockMapEntry-
> >Length)) {
> +          Status = Fvb->Write (
> +                          Fvb,
> +                          LbaNumber,
> +                          (UINTN)(CurrWritePtr - LinearOffset),
> +                          &CurrWriteSize,
> +                          CurrBuffer
> +                          );
> +          return Status;
> +        } else {
> +          Size   = (UINT32)(LinearOffset + PtrBlockMapEntry->Length -
> CurrWritePtr);
> +          Status = Fvb->Write (
> +                          Fvb,
> +                          LbaNumber,
> +                          (UINTN)(CurrWritePtr - LinearOffset),
> +                          &Size,
> +                          CurrBuffer
> +                          );
> +          if (EFI_ERROR (Status)) {
> +            return Status;
> +          }
> +
> +          CurrWritePtr  = LinearOffset + PtrBlockMapEntry->Length;
> +          CurrBuffer    = CurrBuffer + Size;
> +          CurrWriteSize = CurrWriteSize - Size;
> +        }
> +      }
> +
> +      LinearOffset += PtrBlockMapEntry->Length;
> +      LbaNumber++;
> +    }
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Record variable error flag.
> +
> +  @param[in] Flag               Variable error flag to record.
> +  @param[in] VariableName       Name of variable.
> +  @param[in] VendorGuid         Guid of variable.
> +  @param[in] Attributes         Attributes of the variable.
> +  @param[in] VariableSize       Size of the variable.
> +
> +**/
> +VOID
> +RecordVarErrorFlag (
> +  IN VAR_ERROR_FLAG  Flag,
> +  IN CHAR16          *VariableName,
> +  IN EFI_GUID        *VendorGuid,
> +  IN UINT32          Attributes,
> +  IN UINTN           VariableSize
> +  )
> +{
> +  EFI_STATUS              Status;
> +  VARIABLE_POINTER_TRACK  Variable;
> +  VAR_ERROR_FLAG          *VarErrFlag;
> +  VAR_ERROR_FLAG          TempFlag;
> +
> +  DEBUG_CODE_BEGIN ();
> +  DEBUG ((DEBUG_ERROR, "RecordVarErrorFlag (0x%02x) %s:%g - 0x%08x -
> 0x%x\n", Flag, VariableName, VendorGuid, Attributes, VariableSize));
> +  if (Flag == VAR_ERROR_FLAG_SYSTEM_ERROR) {
> +    if (AtRuntime ()) {
> +      DEBUG ((DEBUG_ERROR, "CommonRuntimeVariableSpace = 0x%x -
> CommonVariableTotalSize = 0x%x\n", mVariableModuleGlobal-
> >CommonRuntimeVariableSpace, mVariableModuleGlobal-
> >CommonVariableTotalSize));
> +    } else {
> +      DEBUG ((DEBUG_ERROR, "CommonVariableSpace = 0x%x -
> CommonVariableTotalSize = 0x%x\n", mVariableModuleGlobal-
> >CommonVariableSpace, mVariableModuleGlobal->CommonVariableTotalSize));
> +    }
> +  } else {
> +    DEBUG ((DEBUG_ERROR, "CommonMaxUserVariableSpace = 0x%x -
> CommonUserVariableTotalSize = 0x%x\n", mVariableModuleGlobal-
> >CommonMaxUserVariableSpace, mVariableModuleGlobal-
> >CommonUserVariableTotalSize));
> +  }
> +
> +  DEBUG_CODE_END ();
> +
> +  if (!mEndOfDxe) {
> +    //
> +    // Before EndOfDxe, just record the current boot variable error flag to local
> variable,
> +    // and leave the variable error flag in NV flash as the last boot variable error
> flag.
> +    // After EndOfDxe in InitializeVarErrorFlag (), the variable error flag in NV
> flash
> +    // will be initialized to this local current boot variable error flag.
> +    //
> +    mCurrentBootVarErrFlag &= Flag;
> +    return;
> +  }
> +
> +  //
> +  // Record error flag (it should have be initialized).
> +  //
> +  Status = FindVariable (
> +             VAR_ERROR_FLAG_NAME,
> +             &gEdkiiVarErrorFlagGuid,
> +             &Variable,
> +             &mVariableModuleGlobal->VariableGlobal,
> +             FALSE
> +             );
> +  if (!EFI_ERROR (Status)) {
> +    VarErrFlag = (VAR_ERROR_FLAG *)GetVariableDataPtr (Variable.CurrPtr,
> mVariableModuleGlobal->VariableGlobal.AuthFormat);
> +    TempFlag   = *VarErrFlag;
> +    TempFlag  &= Flag;
> +    if (TempFlag == *VarErrFlag) {
> +      return;
> +    }
> +
> +    Status = UpdateVariableStore (
> +               &mVariableModuleGlobal->VariableGlobal,
> +               FALSE,
> +               FALSE,
> +               mVariableModuleGlobal->FvbInstance,
> +               (UINTN)VarErrFlag - (UINTN)mNvVariableCache +
> (UINTN)mVariableModuleGlobal->VariableGlobal.NonVolatileVariableBase,
> +               sizeof (TempFlag),
> +               &TempFlag
> +               );
> +    if (!EFI_ERROR (Status)) {
> +      //
> +      // Update the data in NV cache.
> +      //
> +      *VarErrFlag = TempFlag;
> +      Status      =  SynchronizeRuntimeVariableCache (
> +                       &mVariableModuleGlobal-
> >VariableGlobal.VariableRuntimeCacheContext.VariableRuntimeNvCache,
> +                       0,
> +                       mNvVariableCache->Size
> +                       );
> +      ASSERT_EFI_ERROR (Status);
> +    }
> +  }
> +}
> +
> +/**
> +  Initialize variable error flag.
> +
> +  Before EndOfDxe, the variable indicates the last boot variable error flag,
> +  then it means the last boot variable error flag must be got before EndOfDxe.
> +  After EndOfDxe, the variable indicates the current boot variable error flag,
> +  then it means the current boot variable error flag must be got after EndOfDxe.
> +
> +**/
> +VOID
> +InitializeVarErrorFlag (
> +  VOID
> +  )
> +{
> +  EFI_STATUS              Status;
> +  VARIABLE_POINTER_TRACK  Variable;
> +  VAR_ERROR_FLAG          Flag;
> +  VAR_ERROR_FLAG          VarErrFlag;
> +
> +  if (!mEndOfDxe) {
> +    return;
> +  }
> +
> +  Flag = mCurrentBootVarErrFlag;
> +  DEBUG ((DEBUG_INFO, "Initialize variable error flag (%02x)\n", Flag));
> +
> +  Status = FindVariable (
> +             VAR_ERROR_FLAG_NAME,
> +             &gEdkiiVarErrorFlagGuid,
> +             &Variable,
> +             &mVariableModuleGlobal->VariableGlobal,
> +             FALSE
> +             );
> +  if (!EFI_ERROR (Status)) {
> +    VarErrFlag = *((VAR_ERROR_FLAG *)GetVariableDataPtr (Variable.CurrPtr,
> mVariableModuleGlobal->VariableGlobal.AuthFormat));
> +    if (VarErrFlag == Flag) {
> +      return;
> +    }
> +  }
> +
> +  UpdateVariable (
> +    VAR_ERROR_FLAG_NAME,
> +    &gEdkiiVarErrorFlagGuid,
> +    &Flag,
> +    sizeof (Flag),
> +    VARIABLE_ATTRIBUTE_NV_BS_RT,
> +    0,
> +    0,
> +    &Variable,
> +    NULL
> +    );
> +}
> +
> +/**
> +  Is user variable?
> +
> +  @param[in] Variable   Pointer to variable header.
> +
> +  @retval TRUE          User variable.
> +  @retval FALSE         System variable.
> +
> +**/
> +BOOLEAN
> +IsUserVariable (
> +  IN VARIABLE_HEADER  *Variable
> +  )
> +{
> +  VAR_CHECK_VARIABLE_PROPERTY  Property;
> +
> +  //
> +  // Only after End Of Dxe, the variables belong to system variable are fixed.
> +  // If PcdMaxUserNvStorageVariableSize is 0, it means user variable share the
> same NV storage with system variable,
> +  // then no need to check if the variable is user variable or not specially.
> +  //
> +  if (mEndOfDxe && (mVariableModuleGlobal-
> >CommonMaxUserVariableSpace != mVariableModuleGlobal-
> >CommonVariableSpace)) {
> +    if (VarCheckLibVariablePropertyGet (
> +          GetVariableNamePtr (Variable, mVariableModuleGlobal-
> >VariableGlobal.AuthFormat),
> +          GetVendorGuidPtr (Variable, mVariableModuleGlobal-
> >VariableGlobal.AuthFormat),
> +          &Property
> +          ) == EFI_NOT_FOUND)
> +    {
> +      return TRUE;
> +    }
> +  }
> +
> +  return FALSE;
> +}
> +
> +/**
> +  Calculate common user variable total size.
> +
> +**/
> +VOID
> +CalculateCommonUserVariableTotalSize (
> +  VOID
> +  )
> +{
> +  VARIABLE_HEADER              *Variable;
> +  VARIABLE_HEADER              *NextVariable;
> +  UINTN                        VariableSize;
> +  VAR_CHECK_VARIABLE_PROPERTY  Property;
> +
> +  //
> +  // Only after End Of Dxe, the variables belong to system variable are fixed.
> +  // If PcdMaxUserNvStorageVariableSize is 0, it means user variable share the
> same NV storage with system variable,
> +  // then no need to calculate the common user variable total size specially.
> +  //
> +  if (mEndOfDxe && (mVariableModuleGlobal-
> >CommonMaxUserVariableSpace != mVariableModuleGlobal-
> >CommonVariableSpace)) {
> +    Variable = GetStartPointer (mNvVariableCache);
> +    while (IsValidVariableHeader (Variable, GetEndPointer (mNvVariableCache),
> mVariableModuleGlobal->VariableGlobal.AuthFormat)) {
> +      NextVariable = GetNextVariablePtr (Variable, mVariableModuleGlobal-
> >VariableGlobal.AuthFormat);
> +      VariableSize = (UINTN)NextVariable - (UINTN)Variable;
> +      if ((Variable->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD) !=
> EFI_VARIABLE_HARDWARE_ERROR_RECORD) {
> +        if (VarCheckLibVariablePropertyGet (
> +              GetVariableNamePtr (Variable, mVariableModuleGlobal-
> >VariableGlobal.AuthFormat),
> +              GetVendorGuidPtr (Variable, mVariableModuleGlobal-
> >VariableGlobal.AuthFormat),
> +              &Property
> +              ) == EFI_NOT_FOUND)
> +        {
> +          //
> +          // No property, it is user variable.
> +          //
> +          mVariableModuleGlobal->CommonUserVariableTotalSize += VariableSize;
> +        }
> +      }
> +
> +      Variable = NextVariable;
> +    }
> +  }
> +}
> +
> +/**
> +  Initialize variable quota.
> +
> +**/
> +VOID
> +InitializeVariableQuota (
> +  VOID
> +  )
> +{
> +  if (!mEndOfDxe) {
> +    return;
> +  }
> +
> +  InitializeVarErrorFlag ();
> +  CalculateCommonUserVariableTotalSize ();
> +}
> +
> +/**
> +  Finds variable in storage blocks of volatile and non-volatile storage areas.
> +
> +  This code finds variable in storage blocks of volatile and non-volatile storage
> areas.
> +  If VariableName is an empty string, then we just return the first
> +  qualified variable without comparing VariableName and VendorGuid.
> +  If IgnoreRtCheck is TRUE, then we ignore the
> EFI_VARIABLE_RUNTIME_ACCESS attribute check
> +  at runtime when searching existing variable, only VariableName and
> VendorGuid are compared.
> +  Otherwise, variables without EFI_VARIABLE_RUNTIME_ACCESS are not visible
> at runtime.
> +
> +  @param[in]   VariableName           Name of the variable to be found.
> +  @param[in]   VendorGuid             Vendor GUID to be found.
> +  @param[out]  PtrTrack               VARIABLE_POINTER_TRACK structure for
> output,
> +                                      including the range searched and the target position.
> +  @param[in]   Global                 Pointer to VARIABLE_GLOBAL structure,
> including
> +                                      base of volatile variable storage area, base of
> +                                      NV variable storage area, and a lock.
> +  @param[in]   IgnoreRtCheck          Ignore EFI_VARIABLE_RUNTIME_ACCESS
> attribute
> +                                      check at runtime when searching variable.
> +
> +  @retval EFI_INVALID_PARAMETER       If VariableName is not an empty string,
> while
> +                                      VendorGuid is NULL.
> +  @retval EFI_SUCCESS                 Variable successfully found.
> +  @retval EFI_NOT_FOUND               Variable not found
> +
> +**/
> +EFI_STATUS
> +FindVariable (
> +  IN  CHAR16                  *VariableName,
> +  IN  EFI_GUID                *VendorGuid,
> +  OUT VARIABLE_POINTER_TRACK  *PtrTrack,
> +  IN  VARIABLE_GLOBAL         *Global,
> +  IN  BOOLEAN                 IgnoreRtCheck
> +  )
> +{
> +  EFI_STATUS             Status;
> +  VARIABLE_STORE_HEADER  *VariableStoreHeader[VariableStoreTypeMax];
> +  VARIABLE_STORE_TYPE    Type;
> +
> +  if ((VariableName[0] != 0) && (VendorGuid == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  //
> +  // 0: Volatile, 1: HOB, 2: Non-Volatile.
> +  // The index and attributes mapping must be kept in this order as
> RuntimeServiceGetNextVariableName
> +  // make use of this mapping to implement search algorithm.
> +  //
> +  VariableStoreHeader[VariableStoreTypeVolatile] =
> (VARIABLE_STORE_HEADER *)(UINTN)Global->VolatileVariableBase;
> +  VariableStoreHeader[VariableStoreTypeHob]      = (VARIABLE_STORE_HEADER
> *)(UINTN)Global->HobVariableBase;
> +  VariableStoreHeader[VariableStoreTypeNv]       = mNvVariableCache;
> +
> +  //
> +  // Find the variable by walk through HOB, volatile and non-volatile variable
> store.
> +  //
> +  for (Type = (VARIABLE_STORE_TYPE)0; Type < VariableStoreTypeMax; Type++)
> {
> +    if (VariableStoreHeader[Type] == NULL) {
> +      continue;
> +    }
> +
> +    PtrTrack->StartPtr = GetStartPointer (VariableStoreHeader[Type]);
> +    PtrTrack->EndPtr   = GetEndPointer (VariableStoreHeader[Type]);
> +    PtrTrack->Volatile = (BOOLEAN)(Type == VariableStoreTypeVolatile);
> +
> +    Status =  FindVariableEx (
> +                VariableName,
> +                VendorGuid,
> +                IgnoreRtCheck,
> +                PtrTrack,
> +                mVariableModuleGlobal->VariableGlobal.AuthFormat
> +                );
> +    if (!EFI_ERROR (Status)) {
> +      return Status;
> +    }
> +  }
> +
> +  return EFI_NOT_FOUND;
> +}
> +
> +/**
> +  Get index from supported language codes according to language string.
> +
> +  This code is used to get corresponding index in supported language codes. It
> can handle
> +  RFC4646 and ISO639 language tags.
> +  In ISO639 language tags, take 3-characters as a delimitation to find matched
> string and calculate the index.
> +  In RFC4646 language tags, take semicolon as a delimitation to find matched
> string and calculate the index.
> +
> +  For example:
> +    SupportedLang  = "engfraengfra"
> +    Lang           = "eng"
> +    Iso639Language = TRUE
> +  The return value is "0".
> +  Another example:
> +    SupportedLang  = "en;fr;en-US;fr-FR"
> +    Lang           = "fr-FR"
> +    Iso639Language = FALSE
> +  The return value is "3".
> +
> +  @param  SupportedLang               Platform supported language codes.
> +  @param  Lang                        Configured language.
> +  @param  Iso639Language              A bool value to signify if the handler is
> operated on ISO639 or RFC4646.
> +
> +  @retval The index of language in the language codes.
> +
> +**/
> +UINTN
> +GetIndexFromSupportedLangCodes (
> +  IN  CHAR8    *SupportedLang,
> +  IN  CHAR8    *Lang,
> +  IN  BOOLEAN  Iso639Language
> +  )
> +{
> +  UINTN  Index;
> +  UINTN  CompareLength;
> +  UINTN  LanguageLength;
> +
> +  if (Iso639Language) {
> +    CompareLength = ISO_639_2_ENTRY_SIZE;
> +    for (Index = 0; Index < AsciiStrLen (SupportedLang); Index += CompareLength)
> {
> +      if (AsciiStrnCmp (Lang, SupportedLang + Index, CompareLength) == 0) {
> +        //
> +        // Successfully find the index of Lang string in SupportedLang string.
> +        //
> +        Index = Index / CompareLength;
> +        return Index;
> +      }
> +    }
> +
> +    ASSERT (FALSE);
> +    return 0;
> +  } else {
> +    //
> +    // Compare RFC4646 language code
> +    //
> +    Index = 0;
> +    for (LanguageLength = 0; Lang[LanguageLength] != '\0'; LanguageLength++)
> {
> +    }
> +
> +    for (Index = 0; *SupportedLang != '\0'; Index++, SupportedLang +=
> CompareLength) {
> +      //
> +      // Skip ';' characters in SupportedLang
> +      //
> +      for ( ; *SupportedLang != '\0' && *SupportedLang == ';'; SupportedLang++) {
> +      }
> +
> +      //
> +      // Determine the length of the next language code in SupportedLang
> +      //
> +      for (CompareLength = 0; SupportedLang[CompareLength] != '\0' &&
> SupportedLang[CompareLength] != ';'; CompareLength++) {
> +      }
> +
> +      if ((CompareLength == LanguageLength) &&
> +          (AsciiStrnCmp (Lang, SupportedLang, CompareLength) == 0))
> +      {
> +        //
> +        // Successfully find the index of Lang string in SupportedLang string.
> +        //
> +        return Index;
> +      }
> +    }
> +
> +    ASSERT (FALSE);
> +    return 0;
> +  }
> +}
> +
> +/**
> +  Get language string from supported language codes according to index.
> +
> +  This code is used to get corresponding language strings in supported language
> codes. It can handle
> +  RFC4646 and ISO639 language tags.
> +  In ISO639 language tags, take 3-characters as a delimitation. Find language
> string according to the index.
> +  In RFC4646 language tags, take semicolon as a delimitation. Find language
> string according to the index.
> +
> +  For example:
> +    SupportedLang  = "engfraengfra"
> +    Index          = "1"
> +    Iso639Language = TRUE
> +  The return value is "fra".
> +  Another example:
> +    SupportedLang  = "en;fr;en-US;fr-FR"
> +    Index          = "1"
> +    Iso639Language = FALSE
> +  The return value is "fr".
> +
> +  @param  SupportedLang               Platform supported language codes.
> +  @param  Index                       The index in supported language codes.
> +  @param  Iso639Language              A bool value to signify if the handler is
> operated on ISO639 or RFC4646.
> +
> +  @retval The language string in the language codes.
> +
> +**/
> +CHAR8 *
> +GetLangFromSupportedLangCodes (
> +  IN  CHAR8    *SupportedLang,
> +  IN  UINTN    Index,
> +  IN  BOOLEAN  Iso639Language
> +  )
> +{
> +  UINTN  SubIndex;
> +  UINTN  CompareLength;
> +  CHAR8  *Supported;
> +
> +  SubIndex  = 0;
> +  Supported = SupportedLang;
> +  if (Iso639Language) {
> +    //
> +    // According to the index of Lang string in SupportedLang string to get the
> language.
> +    // This code will be invoked in RUNTIME, therefore there is not a memory
> allocate/free operation.
> +    // In driver entry, it pre-allocates a runtime attribute memory to
> accommodate this string.
> +    //
> +    CompareLength                              = ISO_639_2_ENTRY_SIZE;
> +    mVariableModuleGlobal->Lang[CompareLength] = '\0';
> +    return CopyMem (mVariableModuleGlobal->Lang, SupportedLang + Index *
> CompareLength, CompareLength);
> +  } else {
> +    while (TRUE) {
> +      //
> +      // Take semicolon as delimitation, sequentially traverse supported language
> codes.
> +      //
> +      for (CompareLength = 0; *Supported != ';' && *Supported != '\0';
> CompareLength++) {
> +        Supported++;
> +      }
> +
> +      if ((*Supported == '\0') && (SubIndex != Index)) {
> +        //
> +        // Have completed the traverse, but not find corrsponding string.
> +        // This case is not allowed to happen.
> +        //
> +        ASSERT (FALSE);
> +        return NULL;
> +      }
> +
> +      if (SubIndex == Index) {
> +        //
> +        // According to the index of Lang string in SupportedLang string to get the
> language.
> +        // As this code will be invoked in RUNTIME, therefore there is not memory
> allocate/free operation.
> +        // In driver entry, it pre-allocates a runtime attribute memory to
> accommodate this string.
> +        //
> +        mVariableModuleGlobal->PlatformLang[CompareLength] = '\0';
> +        return CopyMem (mVariableModuleGlobal->PlatformLang, Supported -
> CompareLength, CompareLength);
> +      }
> +
> +      SubIndex++;
> +
> +      //
> +      // Skip ';' characters in Supported
> +      //
> +      for ( ; *Supported != '\0' && *Supported == ';'; Supported++) {
> +      }
> +    }
> +  }
> +}
> +
> +/**
> +  Returns a pointer to an allocated buffer that contains the best matching
> language
> +  from a set of supported languages.
> +
> +  This function supports both ISO 639-2 and RFC 4646 language codes, but
> language
> +  code types may not be mixed in a single call to this function. This function
> +  supports a variable argument list that allows the caller to pass in a prioritized
> +  list of language codes to test against all the language codes in
> SupportedLanguages.
> +
> +  If SupportedLanguages is NULL, then ASSERT().
> +
> +  @param[in]  SupportedLanguages  A pointer to a Null-terminated ASCII string
> that
> +                                  contains a set of language codes in the format
> +                                  specified by Iso639Language.
> +  @param[in]  Iso639Language      If not zero, then all language codes are
> assumed to be
> +                                  in ISO 639-2 format.  If zero, then all language
> +                                  codes are assumed to be in RFC 4646 language format
> +  @param[in]  ...                 A variable argument list that contains pointers to
> +                                  Null-terminated ASCII strings that contain one or more
> +                                  language codes in the format specified by Iso639Language.
> +                                  The first language code from each of these language
> +                                  code lists is used to determine if it is an exact or
> +                                  close match to any of the language codes in
> +                                  SupportedLanguages.  Close matches only apply to RFC 4646
> +                                  language codes, and the matching algorithm from RFC 4647
> +                                  is used to determine if a close match is present.  If
> +                                  an exact or close match is found, then the matching
> +                                  language code from SupportedLanguages is returned.  If
> +                                  no matches are found, then the next variable argument
> +                                  parameter is evaluated.  The variable argument list
> +                                  is terminated by a NULL.
> +
> +  @retval NULL   The best matching language could not be found in
> SupportedLanguages.
> +  @retval NULL   There are not enough resources available to return the best
> matching
> +                 language.
> +  @retval Other  A pointer to a Null-terminated ASCII string that is the best
> matching
> +                 language in SupportedLanguages.
> +
> +**/
> +CHAR8 *
> +EFIAPI
> +VariableGetBestLanguage (
> +  IN CONST CHAR8  *SupportedLanguages,
> +  IN UINTN        Iso639Language,
> +  ...
> +  )
> +{
> +  VA_LIST      Args;
> +  CHAR8        *Language;
> +  UINTN        CompareLength;
> +  UINTN        LanguageLength;
> +  CONST CHAR8  *Supported;
> +  CHAR8        *Buffer;
> +
> +  if (SupportedLanguages == NULL) {
> +    return NULL;
> +  }
> +
> +  VA_START (Args, Iso639Language);
> +  while ((Language = VA_ARG (Args, CHAR8 *)) != NULL) {
> +    //
> +    // Default to ISO 639-2 mode
> +    //
> +    CompareLength  = 3;
> +    LanguageLength = MIN (3, AsciiStrLen (Language));
> +
> +    //
> +    // If in RFC 4646 mode, then determine the length of the first RFC 4646
> language code in Language
> +    //
> +    if (Iso639Language == 0) {
> +      for (LanguageLength = 0; Language[LanguageLength] != 0 &&
> Language[LanguageLength] != ';'; LanguageLength++) {
> +      }
> +    }
> +
> +    //
> +    // Trim back the length of Language used until it is empty
> +    //
> +    while (LanguageLength > 0) {
> +      //
> +      // Loop through all language codes in SupportedLanguages
> +      //
> +      for (Supported = SupportedLanguages; *Supported != '\0'; Supported +=
> CompareLength) {
> +        //
> +        // In RFC 4646 mode, then Loop through all language codes in
> SupportedLanguages
> +        //
> +        if (Iso639Language == 0) {
> +          //
> +          // Skip ';' characters in Supported
> +          //
> +          for ( ; *Supported != '\0' && *Supported == ';'; Supported++) {
> +          }
> +
> +          //
> +          // Determine the length of the next language code in Supported
> +          //
> +          for (CompareLength = 0; Supported[CompareLength] != 0 &&
> Supported[CompareLength] != ';'; CompareLength++) {
> +          }
> +
> +          //
> +          // If Language is longer than the Supported, then skip to the next
> language
> +          //
> +          if (LanguageLength > CompareLength) {
> +            continue;
> +          }
> +        }
> +
> +        //
> +        // See if the first LanguageLength characters in Supported match Language
> +        //
> +        if (AsciiStrnCmp (Supported, Language, LanguageLength) == 0) {
> +          VA_END (Args);
> +
> +          Buffer                = (Iso639Language != 0) ? mVariableModuleGlobal->Lang :
> mVariableModuleGlobal->PlatformLang;
> +          Buffer[CompareLength] = '\0';
> +          return CopyMem (Buffer, Supported, CompareLength);
> +        }
> +      }
> +
> +      if (Iso639Language != 0) {
> +        //
> +        // If ISO 639 mode, then each language can only be tested once
> +        //
> +        LanguageLength = 0;
> +      } else {
> +        //
> +        // If RFC 4646 mode, then trim Language from the right to the next '-'
> character
> +        //
> +        for (LanguageLength--; LanguageLength > 0 &&
> Language[LanguageLength] != '-'; LanguageLength--) {
> +        }
> +      }
> +    }
> +  }
> +
> +  VA_END (Args);
> +
> +  //
> +  // No matches were found
> +  //
> +  return NULL;
> +}
> +
> +/**
> +  This function is to check if the remaining variable space is enough to set
> +  all Variables from argument list successfully. The purpose of the check
> +  is to keep the consistency of the Variables to be in variable storage.
> +
> +  Note: Variables are assumed to be in same storage.
> +  The set sequence of Variables will be same with the sequence of VariableEntry
> from argument list,
> +  so follow the argument sequence to check the Variables.
> +
> +  @param[in] Attributes         Variable attributes for Variable entries.
> +  @param[in] Marker             VA_LIST style variable argument list.
> +                                The variable argument list with type
> VARIABLE_ENTRY_CONSISTENCY *.
> +                                A NULL terminates the list. The VariableSize of
> +                                VARIABLE_ENTRY_CONSISTENCY is the variable data size as
> input.
> +                                It will be changed to variable total size as output.
> +
> +  @retval TRUE                  Have enough variable space to set the Variables
> successfully.
> +  @retval FALSE                 No enough variable space to set the Variables
> successfully.
> +
> +**/
> +BOOLEAN
> +EFIAPI
> +CheckRemainingSpaceForConsistencyInternal (
> +  IN UINT32   Attributes,
> +  IN VA_LIST  Marker
> +  )
> +{
> +  EFI_STATUS                  Status;
> +  VA_LIST                     Args;
> +  VARIABLE_ENTRY_CONSISTENCY  *VariableEntry;
> +  UINT64                      MaximumVariableStorageSize;
> +  UINT64                      RemainingVariableStorageSize;
> +  UINT64                      MaximumVariableSize;
> +  UINTN                       TotalNeededSize;
> +  UINTN                       OriginalVarSize;
> +  VARIABLE_STORE_HEADER       *VariableStoreHeader;
> +  VARIABLE_POINTER_TRACK      VariablePtrTrack;
> +  VARIABLE_HEADER             *NextVariable;
> +  UINTN                       VarNameSize;
> +  UINTN                       VarDataSize;
> +
> +  //
> +  // Non-Volatile related.
> +  //
> +  VariableStoreHeader = mNvVariableCache;
> +
> +  Status = VariableServiceQueryVariableInfoInternal (
> +             Attributes,
> +             &MaximumVariableStorageSize,
> +             &RemainingVariableStorageSize,
> +             &MaximumVariableSize
> +             );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  TotalNeededSize = 0;
> +  VA_COPY (Args, Marker);
> +  VariableEntry = VA_ARG (Args, VARIABLE_ENTRY_CONSISTENCY *);
> +  while (VariableEntry != NULL) {
> +    //
> +    // Calculate variable total size.
> +    //
> +    VarNameSize                 = StrSize (VariableEntry->Name);
> +    VarNameSize                += GET_PAD_SIZE (VarNameSize);
> +    VarDataSize                 = VariableEntry->VariableSize;
> +    VarDataSize                += GET_PAD_SIZE (VarDataSize);
> +    VariableEntry->VariableSize = HEADER_ALIGN (
> +                                    GetVariableHeaderSize (
> +                                      mVariableModuleGlobal->VariableGlobal.AuthFormat
> +                                      ) + VarNameSize + VarDataSize
> +                                    );
> +
> +    TotalNeededSize += VariableEntry->VariableSize;
> +    VariableEntry    = VA_ARG (Args, VARIABLE_ENTRY_CONSISTENCY *);
> +  }
> +
> +  VA_END (Args);
> +
> +  if (RemainingVariableStorageSize >= TotalNeededSize) {
> +    //
> +    // Already have enough space.
> +    //
> +    return TRUE;
> +  } else if (AtRuntime ()) {
> +    //
> +    // At runtime, no reclaim.
> +    // The original variable space of Variables can't be reused.
> +    //
> +    return FALSE;
> +  }
> +
> +  VA_COPY (Args, Marker);
> +  VariableEntry = VA_ARG (Args, VARIABLE_ENTRY_CONSISTENCY *);
> +  while (VariableEntry != NULL) {
> +    //
> +    // Check if Variable[Index] has been present and get its size.
> +    //
> +    OriginalVarSize           = 0;
> +    VariablePtrTrack.StartPtr = GetStartPointer (VariableStoreHeader);
> +    VariablePtrTrack.EndPtr   = GetEndPointer (VariableStoreHeader);
> +    Status                    = FindVariableEx (
> +                                  VariableEntry->Name,
> +                                  VariableEntry->Guid,
> +                                  FALSE,
> +                                  &VariablePtrTrack,
> +                                  mVariableModuleGlobal->VariableGlobal.AuthFormat
> +                                  );
> +    if (!EFI_ERROR (Status)) {
> +      //
> +      // Get size of Variable[Index].
> +      //
> +      NextVariable    = GetNextVariablePtr (VariablePtrTrack.CurrPtr,
> mVariableModuleGlobal->VariableGlobal.AuthFormat);
> +      OriginalVarSize = (UINTN)NextVariable - (UINTN)VariablePtrTrack.CurrPtr;
> +      //
> +      // Add the original size of Variable[Index] to remaining variable storage size.
> +      //
> +      RemainingVariableStorageSize += OriginalVarSize;
> +    }
> +
> +    if (VariableEntry->VariableSize > RemainingVariableStorageSize) {
> +      //
> +      // No enough space for Variable[Index].
> +      //
> +      VA_END (Args);
> +      return FALSE;
> +    }
> +
> +    //
> +    // Sub the (new) size of Variable[Index] from remaining variable storage size.
> +    //
> +    RemainingVariableStorageSize -= VariableEntry->VariableSize;
> +    VariableEntry                 = VA_ARG (Args, VARIABLE_ENTRY_CONSISTENCY *);
> +  }
> +
> +  VA_END (Args);
> +
> +  return TRUE;
> +}
> +
> +/**
> +  This function is to check if the remaining variable space is enough to set
> +  all Variables from argument list successfully. The purpose of the check
> +  is to keep the consistency of the Variables to be in variable storage.
> +
> +  Note: Variables are assumed to be in same storage.
> +  The set sequence of Variables will be same with the sequence of VariableEntry
> from argument list,
> +  so follow the argument sequence to check the Variables.
> +
> +  @param[in] Attributes         Variable attributes for Variable entries.
> +  @param ...                    The variable argument list with type
> VARIABLE_ENTRY_CONSISTENCY *.
> +                                A NULL terminates the list. The VariableSize of
> +                                VARIABLE_ENTRY_CONSISTENCY is the variable data size as
> input.
> +                                It will be changed to variable total size as output.
> +
> +  @retval TRUE                  Have enough variable space to set the Variables
> successfully.
> +  @retval FALSE                 No enough variable space to set the Variables
> successfully.
> +
> +**/
> +BOOLEAN
> +EFIAPI
> +CheckRemainingSpaceForConsistency (
> +  IN UINT32  Attributes,
> +  ...
> +  )
> +{
> +  VA_LIST  Marker;
> +  BOOLEAN  Return;
> +
> +  VA_START (Marker, Attributes);
> +
> +  Return = CheckRemainingSpaceForConsistencyInternal (Attributes, Marker);
> +
> +  VA_END (Marker);
> +
> +  return Return;
> +}
> +
> +/**
> +  Hook the operations in PlatformLangCodes, LangCodes, PlatformLang and
> Lang.
> +
> +  When setting Lang/LangCodes, simultaneously update
> PlatformLang/PlatformLangCodes.
> +
> +  According to UEFI spec, PlatformLangCodes/LangCodes are only set once in
> firmware initialization,
> +  and are read-only. Therefore, in variable driver, only store the original value
> for other use.
> +
> +  @param[in] VariableName       Name of variable.
> +
> +  @param[in] Data               Variable data.
> +
> +  @param[in] DataSize           Size of data. 0 means delete.
> +
> +  @retval EFI_SUCCESS           The update operation is successful or ignored.
> +  @retval EFI_WRITE_PROTECTED   Update PlatformLangCodes/LangCodes at
> runtime.
> +  @retval EFI_OUT_OF_RESOURCES  No enough variable space to do the
> update operation.
> +  @retval Others                Other errors happened during the update operation.
> +
> +**/
> +EFI_STATUS
> +AutoUpdateLangVariable (
> +  IN  CHAR16  *VariableName,
> +  IN  VOID    *Data,
> +  IN  UINTN   DataSize
> +  )
> +{
> +  EFI_STATUS                  Status;
> +  CHAR8                       *BestPlatformLang;
> +  CHAR8                       *BestLang;
> +  UINTN                       Index;
> +  UINT32                      Attributes;
> +  VARIABLE_POINTER_TRACK      Variable;
> +  BOOLEAN                     SetLanguageCodes;
> +  VARIABLE_ENTRY_CONSISTENCY  VariableEntry[2];
> +
> +  //
> +  // Don't do updates for delete operation
> +  //
> +  if (DataSize == 0) {
> +    return EFI_SUCCESS;
> +  }
> +
> +  SetLanguageCodes = FALSE;
> +
> +  if (StrCmp (VariableName, EFI_PLATFORM_LANG_CODES_VARIABLE_NAME)
> == 0) {
> +    //
> +    // PlatformLangCodes is a volatile variable, so it can not be updated at
> runtime.
> +    //
> +    if (AtRuntime ()) {
> +      return EFI_WRITE_PROTECTED;
> +    }
> +
> +    SetLanguageCodes = TRUE;
> +
> +    //
> +    // According to UEFI spec, PlatformLangCodes is only set once in firmware
> initialization, and is read-only
> +    // Therefore, in variable driver, only store the original value for other use.
> +    //
> +    if (mVariableModuleGlobal->PlatformLangCodes != NULL) {
> +      FreePool (mVariableModuleGlobal->PlatformLangCodes);
> +    }
> +
> +    mVariableModuleGlobal->PlatformLangCodes = AllocateRuntimeCopyPool
> (DataSize, Data);
> +    ASSERT (mVariableModuleGlobal->PlatformLangCodes != NULL);
> +
> +    //
> +    // PlatformLang holds a single language from PlatformLangCodes,
> +    // so the size of PlatformLangCodes is enough for the PlatformLang.
> +    //
> +    if (mVariableModuleGlobal->PlatformLang != NULL) {
> +      FreePool (mVariableModuleGlobal->PlatformLang);
> +    }
> +
> +    mVariableModuleGlobal->PlatformLang = AllocateRuntimePool (DataSize);
> +    ASSERT (mVariableModuleGlobal->PlatformLang != NULL);
> +  } else if (StrCmp (VariableName, EFI_LANG_CODES_VARIABLE_NAME) == 0) {
> +    //
> +    // LangCodes is a volatile variable, so it can not be updated at runtime.
> +    //
> +    if (AtRuntime ()) {
> +      return EFI_WRITE_PROTECTED;
> +    }
> +
> +    SetLanguageCodes = TRUE;
> +
> +    //
> +    // According to UEFI spec, LangCodes is only set once in firmware
> initialization, and is read-only
> +    // Therefore, in variable driver, only store the original value for other use.
> +    //
> +    if (mVariableModuleGlobal->LangCodes != NULL) {
> +      FreePool (mVariableModuleGlobal->LangCodes);
> +    }
> +
> +    mVariableModuleGlobal->LangCodes = AllocateRuntimeCopyPool (DataSize,
> Data);
> +    ASSERT (mVariableModuleGlobal->LangCodes != NULL);
> +  }
> +
> +  if (  SetLanguageCodes
> +     && (mVariableModuleGlobal->PlatformLangCodes != NULL)
> +     && (mVariableModuleGlobal->LangCodes != NULL))
> +  {
> +    //
> +    // Update Lang if PlatformLang is already set
> +    // Update PlatformLang if Lang is already set
> +    //
> +    Status = FindVariable (EFI_PLATFORM_LANG_VARIABLE_NAME,
> &gEfiGlobalVariableGuid, &Variable, &mVariableModuleGlobal->VariableGlobal,
> FALSE);
> +    if (!EFI_ERROR (Status)) {
> +      //
> +      // Update Lang
> +      //
> +      VariableName = EFI_PLATFORM_LANG_VARIABLE_NAME;
> +      Data         = GetVariableDataPtr (Variable.CurrPtr, mVariableModuleGlobal-
> >VariableGlobal.AuthFormat);
> +      DataSize     = DataSizeOfVariable (Variable.CurrPtr, mVariableModuleGlobal-
> >VariableGlobal.AuthFormat);
> +    } else {
> +      Status = FindVariable (EFI_LANG_VARIABLE_NAME,
> &gEfiGlobalVariableGuid, &Variable, &mVariableModuleGlobal->VariableGlobal,
> FALSE);
> +      if (!EFI_ERROR (Status)) {
> +        //
> +        // Update PlatformLang
> +        //
> +        VariableName = EFI_LANG_VARIABLE_NAME;
> +        Data         = GetVariableDataPtr (Variable.CurrPtr, mVariableModuleGlobal-
> >VariableGlobal.AuthFormat);
> +        DataSize     = DataSizeOfVariable (Variable.CurrPtr,
> mVariableModuleGlobal->VariableGlobal.AuthFormat);
> +      } else {
> +        //
> +        // Neither PlatformLang nor Lang is set, directly return
> +        //
> +        return EFI_SUCCESS;
> +      }
> +    }
> +  }
> +
> +  Status = EFI_SUCCESS;
> +
> +  //
> +  // According to UEFI spec, "Lang" and "PlatformLang" is NV|BS|RT
> attributions.
> +  //
> +  Attributes = EFI_VARIABLE_NON_VOLATILE |
> EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS;
> +
> +  if (StrCmp (VariableName, EFI_PLATFORM_LANG_VARIABLE_NAME) == 0) {
> +    //
> +    // Update Lang when PlatformLangCodes/LangCodes were set.
> +    //
> +    if ((mVariableModuleGlobal->PlatformLangCodes != NULL) &&
> (mVariableModuleGlobal->LangCodes != NULL)) {
> +      //
> +      // When setting PlatformLang, firstly get most matched language string
> from supported language codes.
> +      //
> +      BestPlatformLang = VariableGetBestLanguage (mVariableModuleGlobal-
> >PlatformLangCodes, FALSE, Data, NULL);
> +      if (BestPlatformLang != NULL) {
> +        //
> +        // Get the corresponding index in language codes.
> +        //
> +        Index = GetIndexFromSupportedLangCodes (mVariableModuleGlobal-
> >PlatformLangCodes, BestPlatformLang, FALSE);
> +
> +        //
> +        // Get the corresponding ISO639 language tag according to RFC4646
> language tag.
> +        //
> +        BestLang = GetLangFromSupportedLangCodes (mVariableModuleGlobal-
> >LangCodes, Index, TRUE);
> +
> +        //
> +        // Check the variable space for both Lang and PlatformLang variable.
> +        //
> +        VariableEntry[0].VariableSize = ISO_639_2_ENTRY_SIZE + 1;
> +        VariableEntry[0].Guid         = &gEfiGlobalVariableGuid;
> +        VariableEntry[0].Name         = EFI_LANG_VARIABLE_NAME;
> +
> +        VariableEntry[1].VariableSize = AsciiStrSize (BestPlatformLang);
> +        VariableEntry[1].Guid         = &gEfiGlobalVariableGuid;
> +        VariableEntry[1].Name         = EFI_PLATFORM_LANG_VARIABLE_NAME;
> +        if (!CheckRemainingSpaceForConsistency
> (VARIABLE_ATTRIBUTE_NV_BS_RT, &VariableEntry[0], &VariableEntry[1],
> NULL)) {
> +          //
> +          // No enough variable space to set both Lang and PlatformLang
> successfully.
> +          //
> +          Status = EFI_OUT_OF_RESOURCES;
> +        } else {
> +          //
> +          // Successfully convert PlatformLang to Lang, and set the BestLang value
> into Lang variable simultaneously.
> +          //
> +          FindVariable (EFI_LANG_VARIABLE_NAME, &gEfiGlobalVariableGuid,
> &Variable, &mVariableModuleGlobal->VariableGlobal, FALSE);
> +
> +          Status = UpdateVariable (
> +                     EFI_LANG_VARIABLE_NAME,
> +                     &gEfiGlobalVariableGuid,
> +                     BestLang,
> +                     ISO_639_2_ENTRY_SIZE + 1,
> +                     Attributes,
> +                     0,
> +                     0,
> +                     &Variable,
> +                     NULL
> +                     );
> +        }
> +
> +        DEBUG ((DEBUG_INFO, "Variable Driver Auto Update PlatformLang,
> PlatformLang:%a, Lang:%a Status: %r\n", BestPlatformLang, BestLang, Status));
> +      }
> +    }
> +  } else if (StrCmp (VariableName, EFI_LANG_VARIABLE_NAME) == 0) {
> +    //
> +    // Update PlatformLang when PlatformLangCodes/LangCodes were set.
> +    //
> +    if ((mVariableModuleGlobal->PlatformLangCodes != NULL) &&
> (mVariableModuleGlobal->LangCodes != NULL)) {
> +      //
> +      // When setting Lang, firstly get most matched language string from
> supported language codes.
> +      //
> +      BestLang = VariableGetBestLanguage (mVariableModuleGlobal->LangCodes,
> TRUE, Data, NULL);
> +      if (BestLang != NULL) {
> +        //
> +        // Get the corresponding index in language codes.
> +        //
> +        Index = GetIndexFromSupportedLangCodes (mVariableModuleGlobal-
> >LangCodes, BestLang, TRUE);
> +
> +        //
> +        // Get the corresponding RFC4646 language tag according to ISO639
> language tag.
> +        //
> +        BestPlatformLang = GetLangFromSupportedLangCodes
> (mVariableModuleGlobal->PlatformLangCodes, Index, FALSE);
> +
> +        //
> +        // Check the variable space for both PlatformLang and Lang variable.
> +        //
> +        VariableEntry[0].VariableSize = AsciiStrSize (BestPlatformLang);
> +        VariableEntry[0].Guid         = &gEfiGlobalVariableGuid;
> +        VariableEntry[0].Name         = EFI_PLATFORM_LANG_VARIABLE_NAME;
> +
> +        VariableEntry[1].VariableSize = ISO_639_2_ENTRY_SIZE + 1;
> +        VariableEntry[1].Guid         = &gEfiGlobalVariableGuid;
> +        VariableEntry[1].Name         = EFI_LANG_VARIABLE_NAME;
> +        if (!CheckRemainingSpaceForConsistency
> (VARIABLE_ATTRIBUTE_NV_BS_RT, &VariableEntry[0], &VariableEntry[1],
> NULL)) {
> +          //
> +          // No enough variable space to set both PlatformLang and Lang
> successfully.
> +          //
> +          Status = EFI_OUT_OF_RESOURCES;
> +        } else {
> +          //
> +          // Successfully convert Lang to PlatformLang, and set the
> BestPlatformLang value into PlatformLang variable simultaneously.
> +          //
> +          FindVariable (EFI_PLATFORM_LANG_VARIABLE_NAME,
> &gEfiGlobalVariableGuid, &Variable, &mVariableModuleGlobal->VariableGlobal,
> FALSE);
> +
> +          Status = UpdateVariable (
> +                     EFI_PLATFORM_LANG_VARIABLE_NAME,
> +                     &gEfiGlobalVariableGuid,
> +                     BestPlatformLang,
> +                     AsciiStrSize (BestPlatformLang),
> +                     Attributes,
> +                     0,
> +                     0,
> +                     &Variable,
> +                     NULL
> +                     );
> +        }
> +
> +        DEBUG ((DEBUG_INFO, "Variable Driver Auto Update Lang, Lang:%a,
> PlatformLang:%a Status: %r\n", BestLang, BestPlatformLang, Status));
> +      }
> +    }
> +  }
> +
> +  if (SetLanguageCodes) {
> +    //
> +    // Continue to set PlatformLangCodes or LangCodes.
> +    //
> +    return EFI_SUCCESS;
> +  } else {
> +    return Status;
> +  }
> +}
> +
> +/**
> +  Check if there's enough free space in storage to write the new variable.
> +
> +  @param[in] NewVariable        Pointer to buffer of new variable.
> +  @param[in] VariableSize       Size of new variable.
> +  @param[in] VariableName       Name of variable.
> +  @param[in] VendorGuid         Guid of variable.
> +  @param[in] Attributes         Attributes of the variable.
> +  @param[in] VolatileFlag       Volatile/non-volatile variable indicator.
> +
> +  @retval EFI_SUCCESS           Enough free space on variable storage.
> +  @retval EFI_BUFFER_TOO_SMALL  There's not enough continuous free space.
> +  @retval EFI_OUT_OF_RESOURCES  There's not enough free space in total.
> +**/
> +EFI_STATUS
> +CheckVariableStoreSpace (
> +  IN  VARIABLE_HEADER  *NewVariable,
> +  IN  UINTN            VariableSize,
> +  IN  CHAR16           *VariableName,
> +  IN  EFI_GUID         *VendorGuid,
> +  IN  UINT32           Attributes,
> +  IN  BOOLEAN          VolatileFlag
> +  )
> +{
> +  BOOLEAN                IsCommonVariable;
> +  BOOLEAN                IsCommonUserVariable;
> +  UINTN                  CommonVariableTotalSize;
> +  UINTN                  CommonUserVariableTotalSize;
> +  UINTN                  HwErrVariableTotalSize;
> +  VARIABLE_STORE_HEADER  *VarStore;
> +
> +  if ((NewVariable == NULL) || (VariableSize == 0)) {
> +    return EFI_SUCCESS;
> +  }
> +
> +  if (VolatileFlag) {
> +    VarStore = (VARIABLE_STORE_HEADER *)(UINTN)
> +               mVariableModuleGlobal->VariableGlobal.VolatileVariableBase;
> +    if ((UINT32)(VariableSize + mVariableModuleGlobal-
> >VolatileLastVariableOffset)
> +        > VarStore->Size)
> +    {
> +      return EFI_BUFFER_TOO_SMALL;
> +    }
> +  } else {
> +    if ((Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD) == 0) {
> +      IsCommonVariable     = TRUE;
> +      IsCommonUserVariable = IsUserVariable (NewVariable);
> +    } else {
> +      IsCommonVariable     = FALSE;
> +      IsCommonUserVariable = FALSE;
> +    }
> +
> +    CommonVariableTotalSize     = mVariableModuleGlobal-
> >CommonVariableTotalSize + VariableSize;
> +    CommonUserVariableTotalSize = mVariableModuleGlobal-
> >CommonUserVariableTotalSize + VariableSize;
> +    HwErrVariableTotalSize      = mVariableModuleGlobal-
> >HwErrVariableTotalSize + VariableSize;
> +
> +    if (  (((Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD) != 0) &&
> +           (HwErrVariableTotalSize > PcdGet32 (PcdHwErrStorageSize)))
> +       || (IsCommonVariable && (CommonVariableTotalSize >
> mVariableModuleGlobal->CommonVariableSpace))
> +       || (IsCommonVariable &&
> +           AtRuntime () &&
> +           (CommonVariableTotalSize > mVariableModuleGlobal-
> >CommonRuntimeVariableSpace))
> +       || (IsCommonUserVariable &&
> +           (CommonUserVariableTotalSize > mVariableModuleGlobal-
> >CommonMaxUserVariableSpace)))
> +    {
> +      if (AtRuntime ()) {
> +        if (IsCommonUserVariable &&
> +            ((VariableSize + mVariableModuleGlobal-
> >CommonUserVariableTotalSize)
> +             > mVariableModuleGlobal->CommonMaxUserVariableSpace))
> +        {
> +          RecordVarErrorFlag (
> +            VAR_ERROR_FLAG_USER_ERROR,
> +            VariableName,
> +            VendorGuid,
> +            Attributes,
> +            VariableSize
> +            );
> +        }
> +
> +        if (IsCommonVariable &&
> +            ((VariableSize + mVariableModuleGlobal->CommonVariableTotalSize)
> +             > mVariableModuleGlobal->CommonRuntimeVariableSpace))
> +        {
> +          RecordVarErrorFlag (
> +            VAR_ERROR_FLAG_SYSTEM_ERROR,
> +            VariableName,
> +            VendorGuid,
> +            Attributes,
> +            VariableSize
> +            );
> +        }
> +
> +        return EFI_OUT_OF_RESOURCES;
> +      }
> +
> +      return EFI_BUFFER_TOO_SMALL;
> +    }
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Fill specific data of auth-variable in buffer.
> +
> +  @param[in,out]  NewVariable        Pointer to buffer of new variable.
> +  @param[in]      OldVariable        Pointer to buffer of old copy of the variable.
> +  @param[in]      Attributes         Attributes of the variable.
> +  @param[in]      KeyIndex           Index of associated public key.
> +  @param[in]      MonotonicCount     Value of associated monotonic count.
> +  @param[in]      TimeStamp          Value of associated TimeStamp.
> +
> +**/
> +VOID
> +SetVariableAuthData (
> +  IN  OUT AUTHENTICATED_VARIABLE_HEADER  *NewVariable,
> +  IN      AUTHENTICATED_VARIABLE_HEADER  *OldVariable,
> +  IN      UINT32                         Attributes,
> +  IN      UINT32                         KeyIndex,
> +  IN      UINT64                         MonotonicCount,
> +  IN      EFI_TIME                       *TimeStamp
> +  )
> +{
> +  NewVariable->PubKeyIndex    = KeyIndex;
> +  NewVariable->MonotonicCount = MonotonicCount;
> +
> +  if ((TimeStamp != NULL) &&
> +      ((Attributes &
> EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) != 0))
> +  {
> +    //
> +    // In the case when the EFI_VARIABLE_APPEND_WRITE attribute is set, only
> +    // when the new TimeStamp value is later than the current timestamp
> associated
> +    // with the variable, we need associate the new timestamp with the updated
> value.
> +    //
> +    if (((Attributes & EFI_VARIABLE_APPEND_WRITE) != 0) &&
> +        (OldVariable != NULL) &&
> +        !VariableCompareTimeStampInternal (&OldVariable->TimeStamp,
> TimeStamp))
> +    {
> +      TimeStamp = &OldVariable->TimeStamp;
> +    }
> +
> +    CopyMem (&NewVariable->TimeStamp, TimeStamp, sizeof (EFI_TIME));
> +  } else {
> +    ZeroMem (&NewVariable->TimeStamp, sizeof (EFI_TIME));
> +  }
> +}
> +
> +/**
> +  Fill the variable data buffer according to variable format on storage.
> +
> +  @param[in,out]  NewVariable        Pointer to buffer of new variable.
> +  @param[in]      OldVariable        Pointer to buffer of old copy of the variable.
> +  @param[in]      VariableName       Name of variable.
> +  @param[in]      VendorGuid         Guid of variable.
> +  @param[in]      Data               Variable data.
> +  @param[in]      DataSize           Size of data. 0 means delete.
> +  @param[in]      Attributes         Attributes of the variable.
> +  @param[in]      KeyIndex           Index of associated public key.
> +  @param[in]      MonotonicCount     Value of associated monotonic count.
> +  @param[in]      TimeStamp          Value of associated TimeStamp.
> +
> +  @retval Size of the new variable.
> +
> +**/
> +UINTN
> +SetVariableData (
> +  IN  OUT VARIABLE_HEADER  *NewVariable,
> +  IN      VARIABLE_HEADER  *OldVariable,
> +  IN      CHAR16           *VariableName,
> +  IN      EFI_GUID         *VendorGuid,
> +  IN      VOID             *Data,
> +  IN      UINTN            DataSize,
> +  IN      UINT32           Attributes,
> +  IN      UINT32           KeyIndex,
> +  IN      UINT64           MonotonicCount,
> +  IN      EFI_TIME         *TimeStamp
> +  )
> +{
> +  EFI_STATUS  Status;
> +  BOOLEAN     AuthFormat;
> +  UINT8       *DataPtr;
> +  UINTN       NameSize;
> +  UINTN       OldDataSize;
> +
> +  AuthFormat = mVariableModuleGlobal->VariableGlobal.AuthFormat;
> +
> +  if (AuthFormat) {
> +    SetVariableAuthData (
> +      (AUTHENTICATED_VARIABLE_HEADER *)NewVariable,
> +      (AUTHENTICATED_VARIABLE_HEADER *)OldVariable,
> +      Attributes,
> +      KeyIndex,
> +      MonotonicCount,
> +      TimeStamp
> +      );
> +  }
> +
> +  NewVariable->StartId    = VARIABLE_DATA;
> +  NewVariable->State      = VAR_ADDED;
> +  NewVariable->Reserved   = 0;
> +  NewVariable->Attributes = Attributes & (~EFI_VARIABLE_APPEND_WRITE);
> +
> +  CopyMem (
> +    GetVendorGuidPtr (NewVariable, AuthFormat),
> +    VendorGuid,
> +    sizeof (EFI_GUID)
> +    );
> +
> +  NameSize = StrSize (VariableName);
> +  SetNameSizeOfVariable (NewVariable, NameSize, AuthFormat);
> +  CopyMem (
> +    (UINT8 *)GetVariableNamePtr (NewVariable, AuthFormat),
> +    VariableName,
> +    NameSize
> +    );
> +
> +  //
> +  // Set data size first otherwise we can't get correct data pointer in the
> +  // buffer of new variable.
> +  //
> +  SetDataSizeOfVariable (NewVariable, DataSize, AuthFormat);
> +  DataPtr = GetVariableDataPtr (NewVariable, AuthFormat);
> +  if (((Attributes & EFI_VARIABLE_APPEND_WRITE) != 0) &&
> +      (OldVariable != NULL) &&
> +      ((OldVariable->State == VAR_ADDED) ||
> +       (OldVariable->State == (VAR_ADDED & VAR_IN_DELETED_TRANSITION))))
> +  {
> +    //
> +    // Get old data, which might be encrypted.
> +    //
> +    OldDataSize = mVariableModuleGlobal->ScratchBufferSize
> +                  - ((UINTN)DataPtr - (UINTN)NewVariable);
> +    Status = ProtectedVariableLibGetByBuffer (
> +               OldVariable,
> +               DataPtr,
> +               (UINT32 *)&OldDataSize,
> +               AuthFormat
> +               );
> +    if (Status == EFI_UNSUPPORTED) {
> +      OldDataSize = DataSizeOfVariable (OldVariable, AuthFormat);
> +      CopyMem (DataPtr, GetVariableDataPtr (OldVariable, AuthFormat),
> OldDataSize);
> +    } else if (EFI_ERROR (Status)) {
> +      ASSERT_EFI_ERROR (Status);
> +      return 0;
> +    }
> +
> +    DataPtr += OldDataSize;
> +    //
> +    // Update data size.
> +    //
> +    SetDataSizeOfVariable (NewVariable, DataSize + OldDataSize, AuthFormat);
> +  }
> +
> +  CopyMem (DataPtr, Data, DataSize);
> +
> +  //
> +  // The actual size of the variable stored in storage should include padding.
> +  //
> +  return ((UINTN)GetNextVariablePtr (NewVariable, AuthFormat) -
> (UINTN)NewVariable);
> +}
> +
> +/**
> +  Update state of given variable as well as its cached copy.
> +
> +  @param[in,out]  Variable        Pointer to the buffer of the variable.
> +  @param[in,out]  CacheVariable   Cache copy of the variable.
> +  @param[in]      NewState        New state value.
> +  @param[in]      Volatile        Volatile/non-volatile variable indicator.
> +
> +  @retval EFI_SUCCESS     Variable state was updated successfully.
> +  @retval Others          Failed to update the variable state.
> +
> +**/
> +EFI_STATUS
> +UpdateVariableState (
> +  IN  OUT VARIABLE_HEADER  *Variable,
> +  IN  OUT VARIABLE_HEADER  *CacheVariable,
> +  IN      UINT8            NewState,
> +  IN      BOOLEAN          Volatile
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  Status = UpdateVariableStore (
> +             &mVariableModuleGlobal->VariableGlobal,
> +             Volatile,
> +             FALSE,
> +             mVariableModuleGlobal->FvbInstance,
> +             (UINTN)&Variable->State,
> +             sizeof (NewState),
> +             &NewState
> +             );
> +  if (!EFI_ERROR (Status) && (CacheVariable != NULL)) {
> +    CacheVariable->State = NewState;
> +  }
> +
> +  return Status;
> +}
> +
> +/**
> +  Flush variable data to variable storage.
> +
> +  @param[in]      VarStoreBase    Base address of variable storage.
> +  @param[in,out]  Offset          Offset to write the variable from.
> +                                  Offset from where next variable can be written.
> +  @param[in,out]  NewVariable     Pointer to the buffer of new variable.
> +  @param[in]      VariableSize    Size of new variable.
> +  @param[in]      Volatile        Volatile/non-volatile variable indicator.
> +  @param[in]      AuthFormat      Auth-variable indicator.
> +
> +  @retval EFI_SUCCESS     Variable(s) were written successfully.
> +  @retval Others          Failed to write the variable data.
> +
> +**/
> +EFI_STATUS
> +WriteVariable (
> +  IN  EFI_PHYSICAL_ADDRESS  VarStoreBase,
> +  IN  OUT UINTN             *Offset,
> +  IN  OUT VARIABLE_HEADER   **NewVariable,
> +  IN      UINT32            VariableSize,
> +  IN      BOOLEAN           Volatile,
> +  IN      BOOLEAN           AuthFormat
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  struct {
> +    UINTN     Offset;
> +    UINT8     *Buffer;
> +    UINT32    Size;
> +    UINT8     State;
> +  }                   WriteSteps[4];
> +  UINTN            Index;
> +  UINTN            Steps;
> +  VARIABLE_HEADER  *Variable;
> +
> +  Variable = *NewVariable;
> +  if (Volatile) {
> +    //
> +    // For non-volatile variable, one step only :
> +    //
> +    WriteSteps[0].Offset = *Offset;
> +    WriteSteps[0].Buffer = (UINT8 *)Variable;
> +    WriteSteps[0].Size   = VariableSize;
> +
> +    Steps = 1;
> +  } else {
> +    //
> +    // Four steps for non-volatile variable:
> +    //
> +    // 1. Write variable header
> +    // 2. Set variable state to header valid
> +    // 3. Write variable name and data
> +    // 4. Set variable state to valid
> +    //
> +    Variable->State      = 0xff;
> +    WriteSteps[0].Offset = *Offset;
> +    WriteSteps[0].Buffer = (UINT8 *)Variable;
> +    WriteSteps[0].Size   = (UINT32)GetVariableHeaderSize (AuthFormat);
> +
> +    WriteSteps[1].State  = VAR_HEADER_VALID_ONLY;
> +    WriteSteps[1].Offset = *Offset + OFFSET_OF (VARIABLE_HEADER, State);
> +    WriteSteps[1].Buffer = &WriteSteps[1].State;
> +    WriteSteps[1].Size   = sizeof (Variable->State);
> +
> +    WriteSteps[2].Offset = *Offset + GetVariableHeaderSize (AuthFormat);
> +    WriteSteps[2].Buffer = (UINT8 *)Variable + GetVariableHeaderSize
> (AuthFormat);
> +    WriteSteps[2].Size   = VariableSize - (UINT32)GetVariableHeaderSize
> (AuthFormat);
> +
> +    WriteSteps[3].State  = VAR_ADDED;
> +    WriteSteps[3].Offset = *Offset + OFFSET_OF (VARIABLE_HEADER, State);
> +    WriteSteps[3].Buffer = &WriteSteps[3].State;
> +    WriteSteps[3].Size   = sizeof (Variable->State);
> +
> +    Steps = ARRAY_SIZE (WriteSteps);
> +  }
> +
> +  for (Index = 0; Index < Steps; ++Index) {
> +    Status = UpdateVariableStore (
> +               &mVariableModuleGlobal->VariableGlobal,
> +               Volatile,
> +               TRUE,
> +               mVariableModuleGlobal->FvbInstance,
> +               WriteSteps[Index].Offset,
> +               WriteSteps[Index].Size,
> +               WriteSteps[Index].Buffer
> +               );
> +    if (EFI_ERROR (Status)) {
> +      ASSERT_EFI_ERROR (Status);
> +      return Status;
> +    }
> +  }
> +
> +  Variable->State = VAR_ADDED;
> +  if (!Volatile) {
> +    CopyMem ((UINT8 *)mNvVariableCache + *Offset, Variable, VariableSize);
> +  }
> +
> +  *NewVariable = (VARIABLE_HEADER *)((UINTN)VarStoreBase + *Offset);
> +  *Offset     += HEADER_ALIGN (VariableSize);
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Rebase the given variable pointer(s) to the equivalent one in given variable
> +  storage via VarStore.
> +
> +  @param[in]      InVarTrackPtr     Pointer to current variable in cache.
> +  @param[out]     OutVarTrackPtr    Pointer to rebased variable against VarStore.
> +  @param[in]      VarStore          Start of variable storage to rebase against.
> +  @param[in]      VariableName      Name of variable.
> +  @param[in]      VendorGuid        Guid of variable.
> +  @param[in]      ByOffset          If TRUE, don't do variable search in VarStore.
> +
> +  @retval EFI_SUCCESS           Variable(s) were deleted successfully.
> +  @retval EFI_INVALID_PARAMETER Invalid parameters passed.
> +  @retval EFI_NOT_FOUND         Given variable (VariableName & VendorGuid)
> was
> +                                not found in VarStore, if ByOffset is FALSE.
> +
> +**/
> +EFI_STATUS
> +RebaseVariablePtr (
> +  IN      VARIABLE_POINTER_TRACK  *InVarTrackPtr,
> +  OUT VARIABLE_POINTER_TRACK      *OutVarTrackPtr,
> +  IN      VARIABLE_STORE_HEADER   *VarStore,
> +  IN      CHAR16                  *VariableName,
> +  IN      EFI_GUID                *VendorGuid,
> +  IN      BOOLEAN                 ByOffset
> +  )
> +{
> +  EFI_STATUS       Status;
> +  BOOLEAN          AuthFormat;
> +  VARIABLE_HEADER  *NewStart;
> +
> +  if ((InVarTrackPtr == NULL) || (OutVarTrackPtr == NULL) || (VarStore ==
> NULL)) {
> +    ASSERT (InVarTrackPtr != NULL);
> +    ASSERT (OutVarTrackPtr != NULL);
> +    ASSERT (VarStore != NULL);
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  AuthFormat = mVariableModuleGlobal->VariableGlobal.AuthFormat;
> +
> +  if (  (InVarTrackPtr->CurrPtr == NULL)
> +     || (InVarTrackPtr->StartPtr == GetStartPointer (VarStore)))
> +  {
> +    CopyMem (OutVarTrackPtr, InVarTrackPtr, sizeof
> (VARIABLE_POINTER_TRACK));
> +    return EFI_SUCCESS;
> +  }
> +
> +  NewStart = GetStartPointer (VarStore);
> +  if (ByOffset) {
> +    OutVarTrackPtr->CurrPtr = (VARIABLE_HEADER *)
> +                              ((UINTN)NewStart + ((UINTN)InVarTrackPtr->CurrPtr -
> +                                                  (UINTN)InVarTrackPtr->StartPtr));
> +
> +    if (InVarTrackPtr->InDeletedTransitionPtr != NULL) {
> +      OutVarTrackPtr->InDeletedTransitionPtr =
> +        (VARIABLE_HEADER *)((UINTN)NewStart +
> +                            ((UINTN)InVarTrackPtr->InDeletedTransitionPtr -
> +                             (UINTN)InVarTrackPtr->StartPtr));
> +    } else {
> +      OutVarTrackPtr->InDeletedTransitionPtr = NULL;
> +    }
> +
> +    OutVarTrackPtr->StartPtr = NewStart;
> +    OutVarTrackPtr->EndPtr   = GetEndPointer (VarStore);
> +  } else {
> +    OutVarTrackPtr->StartPtr = NewStart;
> +    OutVarTrackPtr->EndPtr   = GetEndPointer (VarStore);
> +
> +    Status = FindVariableEx (VariableName, VendorGuid, FALSE, OutVarTrackPtr,
> AuthFormat);
> +    if ((OutVarTrackPtr->CurrPtr == NULL) || EFI_ERROR (Status)) {
> +      return EFI_NOT_FOUND;
> +    }
> +  }
> +
> +  if (  (VarStore == mNvVariableCache)
> +     || ((UINTN)VarStore == (UINTN)mVariableModuleGlobal-
> >VariableGlobal.NonVolatileVariableBase))
> +  {
> +    OutVarTrackPtr->Volatile = FALSE;
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Check if the given variable is from HOB.
> +
> +  @param[in] CacheVariable      Pointer to current variable in cache.
> +
> +  @retval TRUE    The variable is from HOB.
> +  @retval FALSE   The variable is NOT from HOB.
> +
> +**/
> +BOOLEAN
> +IsHobVariable (
> +  IN VARIABLE_POINTER_TRACK  *CacheVariable
> +  )
> +{
> +  VARIABLE_STORE_HEADER  *HobVarStore;
> +
> +  HobVarStore = (VARIABLE_STORE_HEADER *)(UINTN)
> +                mVariableModuleGlobal->VariableGlobal.HobVariableBase;
> +  return (CacheVariable->CurrPtr != NULL &&
> +          HobVarStore != NULL &&
> +          CacheVariable->StartPtr == GetStartPointer (HobVarStore));
> +}
> +
> +/**
> +  Get temporary buffer for a new variable data.
> +
> +  @retval Pointer to the buffer address.
> +
> +**/
> +VARIABLE_HEADER *
> +GetNewVariableBuffer (
> +  VOID
> +  )
> +{
> +  VARIABLE_HEADER        *NewVariable;
> +  VARIABLE_STORE_HEADER  *VarStore;
> +
> +  //
> +  // Tricky part: Use scratch data area at the end of volatile variable store
> +  // as a temporary storage.
> +  //
> +  VarStore = (VARIABLE_STORE_HEADER *)(UINTN)
> +             mVariableModuleGlobal->VariableGlobal.VolatileVariableBase;
> +  NewVariable = GetEndPointer (VarStore);
> +
> +  SetMem (NewVariable, mVariableModuleGlobal->ScratchBufferSize, 0xff);
> +
> +  return NewVariable;
> +}
> +
> +/**
> +  Delete old copies of variable completely.
> +
> +  @param[in]      VariableName       Name of variable.
> +  @param[in]      VendorGuid         Guid of variable.
> +  @param[in]      Variable           Pointer to current variable on storage.
> +  @param[in,out]  CacheVariable      Pointer to current variable in cache.
> +  @param[in]      VolatileFlag       Auth-variable indicator.
> +
> +  @retval EFI_SUCCESS           Variable(s) were deleted successfully.
> +  @retval Others                Failed to update variable state.
> +
> +**/
> +EFI_STATUS
> +DeleteVariable (
> +  IN      CHAR16                  *VariableName,
> +  IN      EFI_GUID                *VendorGuid,
> +  IN      VARIABLE_POINTER_TRACK  *Variable,
> +  IN  OUT VARIABLE_POINTER_TRACK  *CacheVariable,
> +  IN      BOOLEAN                 VolatileFlag
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  if (Variable->InDeletedTransitionPtr != NULL) {
> +    ASSERT (CacheVariable->InDeletedTransitionPtr != NULL);
> +    //
> +    // Both ADDED and IN_DELETED_TRANSITION variable are present,
> +    // set IN_DELETED_TRANSITION one to DELETED state first.
> +    //
> +    Status = UpdateVariableState (
> +               Variable->InDeletedTransitionPtr,
> +               CacheVariable->InDeletedTransitionPtr,
> +               CacheVariable->InDeletedTransitionPtr->State & VAR_DELETED,
> +               VolatileFlag
> +               );
> +    if (EFI_ERROR (Status)) {
> +      return Status;
> +    }
> +  }
> +
> +  ASSERT (CacheVariable->CurrPtr != NULL);
> +  Status = UpdateVariableState (
> +             Variable->CurrPtr,
> +             CacheVariable->CurrPtr,
> +             CacheVariable->CurrPtr->State & VAR_DELETED,
> +             VolatileFlag
> +             );
> +
> +  if (!EFI_ERROR (Status)) {
> +    UpdateVariableInfo (
> +      VariableName,
> +      VendorGuid,
> +      Variable->Volatile,
> +      FALSE,
> +      FALSE,
> +      TRUE,
> +      FALSE,
> +      &gVariableInfo
> +      );
> +    if (!Variable->Volatile) {
> +      FlushHobVariableToFlash (VariableName, VendorGuid);
> +    }
> +  }
> +
> +  return Status;
> +}
> +
> +/**
> +  Check if it's the right time to update a variable.
> +
> +  @param[in] Attributes         Attributes of a variable.
> +
> +  @retval TRUE    It's ready for variable update.
> +  @retval FALSE   It's NOT ready for variable update.
> +
> +**/
> +BOOLEAN
> +ReadyForUpdate (
> +  IN UINT32  Attributes
> +  )
> +{
> +  if ((mVariableModuleGlobal->FvbInstance == NULL) &&
> +      !mVariableModuleGlobal->VariableGlobal.EmuNvMode)
> +  {
> +    //
> +    // The FVB protocol is not ready, so the
> EFI_VARIABLE_WRITE_ARCH_PROTOCOL
> +    // is not installed.
> +    //
> +    if ((Attributes & EFI_VARIABLE_NON_VOLATILE) != 0) {
> +      //
> +      // Trying to update NV variable prior to the installation of
> +      // EFI_VARIABLE_WRITE_ARCH_PROTOCOL
> +      //
> +      DEBUG ((
> +        DEBUG_ERROR,
> +        "Update NV variable before EFI_VARIABLE_WRITE_ARCH_PROTOCOL
> ready - %r\n",
> +        EFI_NOT_AVAILABLE_YET
> +        ));
> +      return FALSE;
> +    } else if ((Attributes & VARIABLE_ATTRIBUTE_AT_AW) != 0) {
> +      //
> +      // Trying to update volatile authenticated variable prior to the
> +      // installation of EFI_VARIABLE_WRITE_ARCH_PROTOCOL. The
> authenticated
> +      // variable perhaps is not initialized, just return here.
> +      //
> +      DEBUG ((
> +        DEBUG_ERROR,
> +        "Update AUTH variable before EFI_VARIABLE_WRITE_ARCH_PROTOCOL
> ready - %r\n",
> +        EFI_NOT_AVAILABLE_YET
> +        ));
> +      return FALSE;
> +    }
> +  }
> +
> +  return TRUE;
> +}
> +
> +/**
> +  Check parameters associated with the variable to update.
> +
> +  @param[in] Variable           Pointer to current variable on storage.
> +  @param[in] CacheVariable      Pointer to current variable in cache.
> +  @param[in] VariableName       Name of variable.
> +  @param[in] VendorGuid         Guid of variable.
> +  @param[in] Data               Variable data.
> +  @param[in] DataSize           Size of data. 0 means delete.
> +  @param[in] Attributes         Attributes of the variable.
> +  @param[in] KeyIndex           Index of associated public key.
> +  @param[in] MonotonicCount     Value of associated monotonic count.
> +  @param[in] TimeStamp          Value of associated TimeStamp.
> +
> +  @retval EFI_SUCCESS           The variable is ok to be updated.
> +  @retval EFI_ALREADY_STARTED   No need to update the variable.
> +  @retval EFI_WRITE_PROTECTED   The variable cannot be updated.
> +  @retval EFI_INVALID_PARAMETER The variable attributes are not valid.
> +  @retval EFI_NOT_FOUND         Trying to delete non-existing variable.
> +
> +**/
> +EFI_STATUS
> +ValidateVariableParameters (
> +  IN VARIABLE_POINTER_TRACK  *Variable,
> +  IN VARIABLE_POINTER_TRACK  *CacheVariable,
> +  IN CHAR16                  *VariableName,
> +  IN EFI_GUID                *VendorGuid,
> +  IN VOID                    *Data,
> +  IN UINTN                   DataSize,
> +  IN UINT32                  Attributes,
> +  IN UINT32                  KeyIndex,
> +  IN UINT64                  MonotonicCount,
> +  IN EFI_TIME                *TimeStamp
> +  )
> +{
> +  BOOLEAN  AuthFlag;
> +
> +  AuthFlag = mVariableModuleGlobal->VariableGlobal.AuthFormat;
> +
> +  if ((DataSize == 0) && ((Attributes & EFI_VARIABLE_APPEND_WRITE) != 0)) {
> +    return EFI_ALREADY_STARTED;
> +  }
> +
> +  if (Variable->CurrPtr != NULL) {
> +    //
> +    // Update/Delete existing variable.
> +    //
> +    if (AtRuntime ()) {
> +      //
> +      // If AtRuntime and the variable is Volatile and Runtime Access,
> +      // the volatile is ReadOnly, and SetVariable should be aborted and
> +      // return EFI_WRITE_PROTECTED.
> +      //
> +      if (Variable->Volatile) {
> +        return EFI_WRITE_PROTECTED;
> +      }
> +
> +      //
> +      // Only variable that have NV attributes can be updated/deleted in Runtime.
> +      //
> +      if ((CacheVariable->CurrPtr->Attributes & EFI_VARIABLE_NON_VOLATILE)
> == 0) {
> +        return EFI_INVALID_PARAMETER;
> +      }
> +
> +      //
> +      // Only variable that have RT attributes can be updated/deleted in Runtime.
> +      //
> +      if ((CacheVariable->CurrPtr->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
> == 0) {
> +        return EFI_INVALID_PARAMETER;
> +      }
> +    }
> +
> +    //
> +    // Variable content unchanged and no need to update timestamp, just return.
> +    //
> +    if (  ((Attributes & EFI_VARIABLE_APPEND_WRITE) == 0)
> +       && (TimeStamp == NULL)
> +       && (DataSizeOfVariable (CacheVariable->CurrPtr, AuthFlag) == DataSize)
> +       && (CompareMem (Data, GetVariableDataPtr (CacheVariable->CurrPtr,
> AuthFlag), DataSize) == 0))
> +    {
> +      UpdateVariableInfo (
> +        VariableName,
> +        VendorGuid,
> +        Variable->Volatile,
> +        FALSE,
> +        TRUE,
> +        FALSE,
> +        FALSE,
> +        &gVariableInfo
> +        );
> +      return EFI_ALREADY_STARTED;
> +    }
> +  } else {
> +    //
> +    // Create a new variable.
> +    //
> +
> +    //
> +    // Make sure we are trying to create a new variable. You cannot delete a
> new
> +    // variable.
> +    //
> +    if ((DataSize == 0) ||
> +        ((Attributes &
> (EFI_VARIABLE_RUNTIME_ACCESS|EFI_VARIABLE_BOOTSERVICE_ACCESS)) ==
> 0))
> +    {
> +      return EFI_NOT_FOUND;
> +    }
> +
> +    //
> +    // Only variable have NV|RT attribute can be created in Runtime.
> +    //
> +    if (  AtRuntime ()
> +       && (  ((Attributes & EFI_VARIABLE_RUNTIME_ACCESS) == 0)
> +          || ((Attributes & EFI_VARIABLE_NON_VOLATILE) == 0)))
> +    {
> +      return EFI_INVALID_PARAMETER;
> +    }
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Update the variable region with Variable information. If
> EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS is set,
> +  index of associated public key is needed.
> +
> +  @param[in]      VariableName       Name of variable.
> +  @param[in]      VendorGuid         Guid of variable.
> +  @param[in]      Data               Variable data.
> +  @param[in]      DataSize           Size of data. 0 means delete.
> +  @param[in]      Attributes         Attributes of the variable.
> +  @param[in]      KeyIndex           Index of associated public key.
> +  @param[in]      MonotonicCount     Value of associated monotonic count.
> +  @param[in,out]  CacheVariable      The variable information which is used
> +                                     to keep track of variable usage.
> +  @param[in]      TimeStamp          Value of associated TimeStamp.
> +
> +  @retval EFI_SUCCESS           The update operation is success.
> +  @retval EFI_OUT_OF_RESOURCES  Variable region is full, can not write other
> data into this region.
> +
> +**/
> +EFI_STATUS
> +UpdateVariable (
> +  IN      CHAR16                  *VariableName,
> +  IN      EFI_GUID                *VendorGuid,
> +  IN      VOID                    *Data,
> +  IN      UINTN                   DataSize,
> +  IN      UINT32                  Attributes      OPTIONAL,
> +  IN      UINT32                  KeyIndex        OPTIONAL,
> +  IN      UINT64                  MonotonicCount  OPTIONAL,
> +  IN OUT  VARIABLE_POINTER_TRACK  *CacheVariable,
> +  IN      EFI_TIME                *TimeStamp      OPTIONAL
> +  )
> +{
> +  EFI_STATUS              Status;
> +  VARIABLE_GLOBAL         *VarGlobal;
> +  VARIABLE_HEADER         *NewVariable;
> +  VARIABLE_HEADER         *NextVariable;
> +  VARIABLE_HEADER         *UpdatingVariable;
> +  UINTN                   VarSize;
> +  UINTN                   UpdateSize;
> +  UINTN                   Offset;
> +  VARIABLE_POINTER_TRACK  *Variable;
> +  VARIABLE_POINTER_TRACK  NvVariable;
> +  VARIABLE_STORE_HEADER   *VariableStoreHeader;
> +  VARIABLE_RUNTIME_CACHE  *VolatileCacheInstance;
> +  BOOLEAN                 IsCommonVariable;
> +  BOOLEAN                 IsCommonUserVariable;
> +  BOOLEAN                 DeleteFlag;
> +  BOOLEAN                 VolatileFlag;
> +  BOOLEAN                 HobVarOnlyFlag;
> +  EFI_PHYSICAL_ADDRESS    VarStoreBase;
> +  UINTN                   *LastVariableOffset;
> +
> +  if (!ReadyForUpdate (Attributes)) {
> +    return EFI_NOT_AVAILABLE_YET;
> +  }
> +
> +  VarGlobal = &mVariableModuleGlobal->VariableGlobal;
> +
> +  if (  (((Attributes & EFI_VARIABLE_APPEND_WRITE) == 0) && (DataSize == 0))
> +     || (Attributes == 0)
> +     || (AtRuntime () && ((Attributes & (EFI_VARIABLE_RUNTIME_ACCESS
> +                                         |EFI_VARIABLE_BOOTSERVICE_ACCESS)) == 0)))
> +  {
> +    DeleteFlag = TRUE;
> +  } else {
> +    DeleteFlag = FALSE;
> +  }
> +
> +  if (  ((Attributes & EFI_VARIABLE_NON_VOLATILE) != 0)
> +     || ((CacheVariable->CurrPtr != NULL) &&
> +         ((CacheVariable->CurrPtr->Attributes & EFI_VARIABLE_NON_VOLATILE) !=
> 0)))
> +  {
> +    VolatileFlag = FALSE;
> +  } else {
> +    VolatileFlag = TRUE;
> +  }
> +
> +  //
> +  // Check if CacheVariable points to the variable in variable HOB.
> +  // If yes, let CacheVariable points to the variable in NV variable cache.
> +  //
> +  HobVarOnlyFlag = FALSE;
> +  if (IsHobVariable (CacheVariable)) {
> +    Status = RebaseVariablePtr (
> +               CacheVariable,
> +               CacheVariable,
> +               mNvVariableCache,
> +               VariableName,
> +               VendorGuid,
> +               FALSE
> +               );
> +    if ((CacheVariable->CurrPtr == NULL) || EFI_ERROR (Status)) {
> +      //
> +      // There is no matched variable in NV variable cache.
> +      //
> +      if (DeleteFlag) {
> +        //
> +        // Leave the deletion to FlushHobVariableToFlash() before return.
> +        //
> +        HobVarOnlyFlag = TRUE;
> +        Status         = EFI_SUCCESS;
> +        goto Done;
> +      }
> +    }
> +  }
> +
> +  //
> +  // Determine the physical position of variable store to update, due to cache
> +  // mechanims of variable service.
> +  //
> +  if ((CacheVariable->CurrPtr == NULL) || CacheVariable->Volatile) {
> +    //
> +    // - Add new variable (volatile or non-volatile); Or
> +    // - Update/delete volatile variable in place.
> +    //
> +    Variable = CacheVariable;
> +  } else {
> +    //
> +    // - Update/Delete existing NV variable.
> +    //    CacheVariable points to the variable in the memory copy of Flash area.
> +    //    Now let Variable points to the same variable in Flash area.
> +    //
> +    VariableStoreHeader = (VARIABLE_STORE_HEADER *)(UINTN)
> +                          VarGlobal->NonVolatileVariableBase;
> +    Variable = &NvVariable;
> +    Status   = RebaseVariablePtr (
> +                 CacheVariable,
> +                 Variable,
> +                 VariableStoreHeader,
> +                 VariableName,
> +                 VendorGuid,
> +                 TRUE
> +                 );
> +    ASSERT_EFI_ERROR (Status);
> +  }
> +
> +  //
> +  // Validate variable parameters.
> +  //
> +  Status = ValidateVariableParameters (
> +             Variable,
> +             CacheVariable,
> +             VariableName,
> +             VendorGuid,
> +             Data,
> +             DataSize,
> +             Attributes,
> +             KeyIndex,
> +             MonotonicCount,
> +             TimeStamp
> +             );
> +  if (EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +  //
> +  // Add or update a variable. Allocate a buffer to hold it temporarily.
> +  //
> +  NewVariable = GetNewVariableBuffer ();
> +
> +  //
> +  // Fill-up variable data first, if necessary.
> +  //
> +  IsCommonVariable     = FALSE;
> +  IsCommonUserVariable = FALSE;
> +  if (DeleteFlag) {
> +    //
> +    // No need to fill up variable buffer when deleting a variable. But the
> +    // buffer is still needed if variable protection is employed.
> +    //
> +    VarSize = 0;
> +  } else {
> +    VarSize = SetVariableData (
> +                NewVariable,
> +                CacheVariable->CurrPtr,
> +                VariableName,
> +                VendorGuid,
> +                Data,
> +                DataSize,
> +                Attributes,
> +                KeyIndex,
> +                MonotonicCount,
> +                TimeStamp
> +                );
> +
> +    if ((Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD) == 0) {
> +      IsCommonVariable     = TRUE;
> +      IsCommonUserVariable = IsUserVariable (NewVariable);
> +    }
> +  }
> +
> +  //
> +  // We might need to do protection for non-volatile variable before flushing
> +  // the data to storage. A null version (meaning no protection) of following
> +  // APIs should simply return EFI_SUCCESS or EFI_UNSUPPORTED without any
> +  // changes to original data.
> +  //
> +  if (!VolatileFlag) {
> +    Status = ProtectedVariableLibUpdate (
> +               Variable->CurrPtr,
> +               Variable->InDeletedTransitionPtr,
> +               NewVariable,
> +               &VarSize
> +               );
> +    if (EFI_ERROR (Status) && (Status != EFI_UNSUPPORTED)) {
> +      return Status;
> +    }
> +
> +    Status = EFI_SUCCESS;
> +  }
> +
> +  //
> +  // Mark the old variable as in delete transition first. There's no such need
> +  // for deleting a variable, even if variable protection is employed.
> +  //
> +  if (  !DeleteFlag
> +     && (CacheVariable->CurrPtr != NULL)
> +     && (  (CacheVariable->CurrPtr->State == VAR_ADDED)
> +        || (CacheVariable->CurrPtr->State == (VAR_ADDED &
> VAR_IN_DELETED_TRANSITION))))
> +  {
> +    Status = UpdateVariableState (
> +               Variable->CurrPtr,
> +               CacheVariable->CurrPtr,
> +               CacheVariable->CurrPtr->State & VAR_IN_DELETED_TRANSITION,
> +               Variable->Volatile
> +               );
> +    if (EFI_ERROR (Status)) {
> +      goto Done;
> +    }
> +  }
> +
> +  //
> +  // Have enough space to store the variable?
> +  //
> +  Status = CheckVariableStoreSpace (
> +             NewVariable,
> +             VarSize,
> +             VariableName,
> +             VendorGuid,
> +             Attributes,
> +             VolatileFlag
> +             );
> +  if (Status == EFI_OUT_OF_RESOURCES) {
> +    //
> +    // Not a chance.
> +    //
> +    goto Done;
> +  }
> +
> +  //
> +  // Maybe not...
> +  //
> +  VarStoreBase = (VolatileFlag) ? VarGlobal->VolatileVariableBase
> +                                : VarGlobal->NonVolatileVariableBase;
> +  LastVariableOffset = (VolatileFlag)
> +                        ? &mVariableModuleGlobal->VolatileLastVariableOffset
> +                        : &mVariableModuleGlobal->NonVolatileLastVariableOffset;
> +  if (!EFI_ERROR (Status)) {
> +    //
> +    // There's enough free space at the tail of variable storage.
> +    //
> +
> +    //
> +    // If non-volatile variable is protected, a separate variable
> (MetaDataHmacVar)
> +    // is always updated along with current updating variable. The buffer pointed
> +    // by NewVariable must have two variables. They should be written at this
> +    // time orderly.
> +    //
> +    NextVariable     = NewVariable;
> +    UpdatingVariable = NULL;
> +    UpdateSize       = 0;
> +    while (  !EFI_ERROR (Status)
> +          && ((UINTN)NextVariable - (UINTN)NewVariable) < VarSize)
> +    {
> +      UpdatingVariable = NextVariable;
> +      NextVariable     = GetNextVariablePtr (UpdatingVariable, VarGlobal-
> >AuthFormat);
> +      UpdateSize       = (UINTN)NextVariable - (UINTN)UpdatingVariable;
> +
> +      Status = WriteVariable (
> +                 VarStoreBase,
> +                 LastVariableOffset,
> +                 &UpdatingVariable,
> +                 (UINT32)UpdateSize,
> +                 VolatileFlag,
> +                 VarGlobal->AuthFormat
> +                 );
> +    }
> +
> +    //
> +    // UpdatingVariable must point to the last written variable. Restore it to
> +    // the first one so that we can calculate the offset in variable storage.
> +    //
> +    UpdatingVariable = (VARIABLE_HEADER *)((UINTN)UpdatingVariable +
> UpdateSize
> +                                           - VarSize);
> +    if ((Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD) != 0) {
> +      mVariableModuleGlobal->HwErrVariableTotalSize += VarSize;
> +    } else {
> +      mVariableModuleGlobal->CommonVariableTotalSize += VarSize;
> +      if (IsCommonUserVariable) {
> +        mVariableModuleGlobal->CommonUserVariableTotalSize += VarSize;
> +      }
> +    }
> +
> +    //
> +    // Mark the old variable(s) as deleted.
> +    //
> +    if (!EFI_ERROR (Status) && (Variable->CurrPtr != NULL)) {
> +      Status = DeleteVariable (
> +                 VariableName,
> +                 VendorGuid,
> +                 Variable,
> +                 CacheVariable,
> +                 VolatileFlag
> +                 );
> +    }
> +  } else {
> +    //
> +    // There's not enough space at the tail of variable storage but there's
> +    // enough free space holes in the whole storage. Perform garbage collection
> +    // & reclaim operation, and integrate the new variable at the same time.
> +    //
> +    Status = Reclaim (
> +               VarStoreBase,
> +               LastVariableOffset,
> +               VolatileFlag,
> +               Variable,
> +               NewVariable,
> +               VarSize
> +               );
> +
> +    if (Variable->CurrPtr != NULL) {
> +      UpdatingVariable = Variable->CurrPtr;
> +    } else {
> +      UpdatingVariable = (VARIABLE_HEADER *)(((UINTN)VarStoreBase +
> *LastVariableOffset) - VarSize);
> +    }
> +
> +    if (EFI_ERROR (Status) &&
> +        ((Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD) == 0))
> +    {
> +      //
> +      // Out of space.
> +      //
> +      IsCommonUserVariable = IsUserVariable (NewVariable);
> +      IsCommonVariable     = TRUE;
> +
> +      if (IsCommonUserVariable &&
> +          ((VarSize + mVariableModuleGlobal->CommonUserVariableTotalSize)
> +           > mVariableModuleGlobal->CommonMaxUserVariableSpace))
> +      {
> +        RecordVarErrorFlag (
> +          VAR_ERROR_FLAG_USER_ERROR,
> +          VariableName,
> +          VendorGuid,
> +          Attributes,
> +          VarSize
> +          );
> +      }
> +
> +      if (IsCommonVariable &&
> +          ((VarSize + mVariableModuleGlobal->CommonVariableTotalSize)
> +           > mVariableModuleGlobal->CommonVariableSpace))
> +      {
> +        RecordVarErrorFlag (
> +          VAR_ERROR_FLAG_SYSTEM_ERROR,
> +          VariableName,
> +          VendorGuid,
> +          Attributes,
> +          VarSize
> +          );
> +      }
> +    }
> +  }
> +
> +Done:
> +  if (!EFI_ERROR (Status)) {
> +    if (!VolatileFlag) {
> +      Offset = (UpdatingVariable != NULL) ? (UINTN)UpdatingVariable -
> (UINTN)VarStoreBase
> +                                          : 0;
> +      Status = ProtectedVariableLibWriteFinal (
> +                 NewVariable,
> +                 VarSize,
> +                 Offset
> +                 );
> +      if (EFI_ERROR (Status) && (Status != EFI_UNSUPPORTED)) {
> +        return Status;
> +      }
> +
> +      Status = EFI_SUCCESS;
> +    }
> +
> +    UpdateVariableInfo (
> +      VariableName,
> +      VendorGuid,
> +      VolatileFlag,
> +      FALSE,
> +      TRUE,
> +      FALSE,
> +      FALSE,
> +      &gVariableInfo
> +      );
> +    //
> +    // HOB copy of the same variable is no longer needed, no matter it has
> +    // been deleted, updated or added from/to real variable storage.
> +    //
> +    if (HobVarOnlyFlag || !VolatileFlag) {
> +      FlushHobVariableToFlash (VariableName, VendorGuid);
> +    }
> +
> +    if (!VolatileFlag) {
> +      VolatileCacheInstance = &(VarGlobal-
> >VariableRuntimeCacheContext.VariableRuntimeNvCache);
> +    } else {
> +      VolatileCacheInstance = &(VarGlobal-
> >VariableRuntimeCacheContext.VariableRuntimeVolatileCache);
> +    }
> +
> +    if (VolatileCacheInstance->Store != NULL) {
> +      Status =  SynchronizeRuntimeVariableCache (
> +                  VolatileCacheInstance,
> +                  0,
> +                  VolatileCacheInstance->Store->Size
> +                  );
> +      ASSERT_EFI_ERROR (Status);
> +    }
> +  } else if (Status == EFI_ALREADY_STARTED) {
> +    //
> +    // Meaning nothing needs to be done. Just return success.
> +    //
> +    Status = EFI_SUCCESS;
> +  }
> +
> +  return Status;
> +}
> +
> +/**
> +
> +  This code finds variable in storage blocks (Volatile or Non-Volatile).
> +
> +  Caution: This function may receive untrusted input.
> +  This function may be invoked in SMM mode, and datasize is external input.
> +  This function will do basic validation, before parse the data.
> +
> +  @param VariableName               Name of Variable to be found.
> +  @param VendorGuid                 Variable vendor GUID.
> +  @param Attributes                 Attribute value of the variable found.
> +  @param DataSize                   Size of Data found. If size is less than the
> +                                    data, this value contains the required size.
> +  @param Data                       The buffer to return the contents of the variable.
> May be NULL
> +                                    with a zero DataSize in order to determine the size buffer
> needed.
> +
> +  @return EFI_INVALID_PARAMETER     Invalid parameter.
> +  @return EFI_SUCCESS               Find the specified variable.
> +  @return EFI_NOT_FOUND             Not found.
> +  @return EFI_BUFFER_TO_SMALL       DataSize is too small for the result.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableServiceGetVariable (
> +  IN      CHAR16    *VariableName,
> +  IN      EFI_GUID  *VendorGuid,
> +  OUT     UINT32    *Attributes OPTIONAL,
> +  IN OUT  UINTN     *DataSize,
> +  OUT     VOID      *Data OPTIONAL
> +  )
> +{
> +  EFI_STATUS              Status;
> +  VARIABLE_POINTER_TRACK  Variable;
> +
> +  if ((VariableName == NULL) || (VendorGuid == NULL) || (DataSize == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (VariableName[0] == 0) {
> +    return EFI_NOT_FOUND;
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock);
> +
> +  Status = FindVariable (VariableName, VendorGuid, &Variable,
> &mVariableModuleGlobal->VariableGlobal, FALSE);
> +  if ((Variable.CurrPtr == NULL) || EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +  //
> +  // Get data and its size
> +  //
> +  if (!Variable.Volatile) {
> +    //
> +    // Currently only non-volatile variable needs protection.
> +    //
> +    Status = ProtectedVariableLibGetByBuffer (
> +               Variable.CurrPtr,
> +               Data,
> +               (UINT32 *)DataSize,
> +               mVariableModuleGlobal->VariableGlobal.AuthFormat
> +               );
> +  }
> +
> +  if (Variable.Volatile || (Status == EFI_UNSUPPORTED)) {
> +    Status = GetVariableData (Variable.CurrPtr, Data, (UINT32 *)DataSize,
> mVariableModuleGlobal->VariableGlobal.AuthFormat);
> +  }
> +
> +  if (!EFI_ERROR (Status)) {
> +    UpdateVariableInfo (VariableName, VendorGuid, Variable.Volatile, TRUE,
> FALSE, FALSE, FALSE, &gVariableInfo);
> +  }
> +
> +Done:
> +  if ((Status == EFI_SUCCESS) || (Status == EFI_BUFFER_TOO_SMALL)) {
> +    if ((Attributes != NULL) && (Variable.CurrPtr != NULL)) {
> +      *Attributes = Variable.CurrPtr->Attributes;
> +    }
> +  }
> +
> +  ReleaseLockOnlyAtBootTime (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock);
> +  return Status;
> +}
> +
> +/**
> +
> +  This code Finds the Next available variable.
> +
> +  Caution: This function may receive untrusted input.
> +  This function may be invoked in SMM mode. This function will do basic
> validation, before parse the data.
> +
> +  @param VariableNameSize           The size of the VariableName buffer. The
> size must be large
> +                                    enough to fit input string supplied in VariableName buffer.
> +  @param VariableName               Pointer to variable name.
> +  @param VendorGuid                 Variable Vendor Guid.
> +
> +  @retval EFI_SUCCESS               The function completed successfully.
> +  @retval EFI_NOT_FOUND             The next variable was not found.
> +  @retval EFI_BUFFER_TOO_SMALL      The VariableNameSize is too small for
> the result.
> +                                    VariableNameSize has been updated with the size needed
> to complete the request.
> +  @retval EFI_INVALID_PARAMETER     VariableNameSize is NULL.
> +  @retval EFI_INVALID_PARAMETER     VariableName is NULL.
> +  @retval EFI_INVALID_PARAMETER     VendorGuid is NULL.
> +  @retval EFI_INVALID_PARAMETER     The input values of VariableName and
> VendorGuid are not a name and
> +                                    GUID of an existing variable.
> +  @retval EFI_INVALID_PARAMETER     Null-terminator is not found in the first
> VariableNameSize bytes of
> +                                    the input VariableName buffer.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableServiceGetNextVariableName (
> +  IN OUT  UINTN     *VariableNameSize,
> +  IN OUT  CHAR16    *VariableName,
> +  IN OUT  EFI_GUID  *VendorGuid
> +  )
> +{
> +  EFI_STATUS             Status;
> +  UINTN                  MaxLen;
> +  UINTN                  VarNameSize;
> +  BOOLEAN                AuthFormat;
> +  VARIABLE_HEADER        *VariablePtr;
> +  VARIABLE_STORE_HEADER  *VariableStoreHeader[VariableStoreTypeMax];
> +
> +  if ((VariableNameSize == NULL) || (VariableName == NULL) || (VendorGuid ==
> NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  AuthFormat = mVariableModuleGlobal->VariableGlobal.AuthFormat;
> +
> +  //
> +  // Calculate the possible maximum length of name string, including the Null
> terminator.
> +  //
> +  MaxLen = *VariableNameSize / sizeof (CHAR16);
> +  if ((MaxLen == 0) || (StrnLenS (VariableName, MaxLen) == MaxLen)) {
> +    //
> +    // Null-terminator is not found in the first VariableNameSize bytes of the
> input VariableName buffer,
> +    // follow spec to return EFI_INVALID_PARAMETER.
> +    //
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock);
> +
> +  //
> +  // 0: Volatile, 1: HOB, 2: Non-Volatile.
> +  // The index and attributes mapping must be kept in this order as FindVariable
> +  // makes use of this mapping to implement search algorithm.
> +  //
> +  VariableStoreHeader[VariableStoreTypeVolatile] =
> (VARIABLE_STORE_HEADER *)(UINTN)mVariableModuleGlobal-
> >VariableGlobal.VolatileVariableBase;
> +  VariableStoreHeader[VariableStoreTypeHob]      = (VARIABLE_STORE_HEADER
> *)(UINTN)mVariableModuleGlobal->VariableGlobal.HobVariableBase;
> +  VariableStoreHeader[VariableStoreTypeNv]       = mNvVariableCache;
> +
> +  Status =  VariableServiceGetNextVariableInternal (
> +              VariableName,
> +              VendorGuid,
> +              VariableStoreHeader,
> +              &VariablePtr,
> +              AuthFormat
> +              );
> +  if (!EFI_ERROR (Status)) {
> +    VarNameSize = NameSizeOfVariable (VariablePtr, AuthFormat);
> +    ASSERT (VarNameSize != 0);
> +    if (VarNameSize <= *VariableNameSize) {
> +      CopyMem (
> +        VariableName,
> +        GetVariableNamePtr (VariablePtr, AuthFormat),
> +        VarNameSize
> +        );
> +      CopyMem (
> +        VendorGuid,
> +        GetVendorGuidPtr (VariablePtr, AuthFormat),
> +        sizeof (EFI_GUID)
> +        );
> +      Status = EFI_SUCCESS;
> +    } else {
> +      Status = EFI_BUFFER_TOO_SMALL;
> +    }
> +
> +    *VariableNameSize = VarNameSize;
> +  }
> +
> +  ReleaseLockOnlyAtBootTime (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock);
> +  return Status;
> +}
> +
> +/**
> +
> +  This code sets variable in storage blocks (Volatile or Non-Volatile).
> +
> +  Caution: This function may receive untrusted input.
> +  This function may be invoked in SMM mode, and datasize and data are
> external input.
> +  This function will do basic validation, before parse the data.
> +  This function will parse the authentication carefully to avoid security issues,
> like
> +  buffer overflow, integer overflow.
> +  This function will check attribute carefully to avoid authentication bypass.
> +
> +  @param VariableName                     Name of Variable to be found.
> +  @param VendorGuid                       Variable vendor GUID.
> +  @param Attributes                       Attribute value of the variable found
> +  @param DataSize                         Size of Data found. If size is less than the
> +                                          data, this value contains the required size.
> +  @param Data                             Data pointer.
> +
> +  @return EFI_INVALID_PARAMETER           Invalid parameter.
> +  @return EFI_SUCCESS                     Set successfully.
> +  @return EFI_OUT_OF_RESOURCES            Resource not enough to set variable.
> +  @return EFI_NOT_FOUND                   Not found.
> +  @return EFI_WRITE_PROTECTED             Variable is read-only.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableServiceSetVariable (
> +  IN CHAR16    *VariableName,
> +  IN EFI_GUID  *VendorGuid,
> +  IN UINT32    Attributes,
> +  IN UINTN     DataSize,
> +  IN VOID      *Data
> +  )
> +{
> +  VARIABLE_POINTER_TRACK  Variable;
> +  EFI_STATUS              Status;
> +  VARIABLE_HEADER         *NextVariable;
> +  EFI_PHYSICAL_ADDRESS    Point;
> +  UINTN                   PayloadSize;
> +  BOOLEAN                 AuthFormat;
> +
> +  AuthFormat = mVariableModuleGlobal->VariableGlobal.AuthFormat;
> +
> +  //
> +  // Check input parameters.
> +  //
> +  if ((VariableName == NULL) || (VariableName[0] == 0) || (VendorGuid ==
> NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if ((DataSize != 0) && (Data == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  //
> +  // Check for reserverd bit in variable attribute.
> +  // EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS is deprecated but we still
> allow
> +  // the delete operation of common authenticated variable at user physical
> presence.
> +  // So leave EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS attribute check
> to AuthVariableLib
> +  //
> +  if ((Attributes & (~(EFI_VARIABLE_ATTRIBUTES_MASK |
> EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS))) != 0) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  //
> +  // Check if the combination of attribute bits is valid.
> +  //
> +  if ((Attributes & (EFI_VARIABLE_RUNTIME_ACCESS |
> EFI_VARIABLE_BOOTSERVICE_ACCESS)) == EFI_VARIABLE_RUNTIME_ACCESS) {
> +    //
> +    // Make sure if runtime bit is set, boot service bit is set also.
> +    //
> +    if ((Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS) != 0) {
> +      return EFI_UNSUPPORTED;
> +    } else {
> +      return EFI_INVALID_PARAMETER;
> +    }
> +  } else if ((Attributes & EFI_VARIABLE_ATTRIBUTES_MASK) ==
> EFI_VARIABLE_NON_VOLATILE) {
> +    //
> +    // Only EFI_VARIABLE_NON_VOLATILE attribute is invalid
> +    //
> +    return EFI_INVALID_PARAMETER;
> +  } else if ((Attributes & VARIABLE_ATTRIBUTE_AT_AW) != 0) {
> +    if (!mVariableModuleGlobal->VariableGlobal.AuthSupport) {
> +      //
> +      // Not support authenticated variable write.
> +      //
> +      return EFI_INVALID_PARAMETER;
> +    }
> +  } else if ((Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD) != 0) {
> +    if (PcdGet32 (PcdHwErrStorageSize) == 0) {
> +      //
> +      // Not support harware error record variable variable.
> +      //
> +      return EFI_INVALID_PARAMETER;
> +    }
> +  }
> +
> +  //
> +  // EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS and
> EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS attribute
> +  // cannot be set both.
> +  //
> +  if (  ((Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS) ==
> EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
> +     && ((Attributes &
> EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) ==
> EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS))
> +  {
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  if ((Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS) ==
> EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS) {
> +    //
> +    //  If DataSize == AUTHINFO_SIZE and then PayloadSize is 0.
> +    //  Maybe it's the delete operation of common authenticated variable at user
> physical presence.
> +    //
> +    if (DataSize != AUTHINFO_SIZE) {
> +      return EFI_UNSUPPORTED;
> +    }
> +
> +    PayloadSize = DataSize - AUTHINFO_SIZE;
> +  } else if ((Attributes &
> EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) ==
> EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) {
> +    //
> +    // Sanity check for EFI_VARIABLE_AUTHENTICATION_2 descriptor.
> +    //
> +    if ((DataSize < OFFSET_OF_AUTHINFO2_CERT_DATA) ||
> +        (((EFI_VARIABLE_AUTHENTICATION_2 *)Data)->AuthInfo.Hdr.dwLength >
> DataSize - (OFFSET_OF (EFI_VARIABLE_AUTHENTICATION_2, AuthInfo))) ||
> +        (((EFI_VARIABLE_AUTHENTICATION_2 *)Data)->AuthInfo.Hdr.dwLength <
> OFFSET_OF (WIN_CERTIFICATE_UEFI_GUID, CertData)))
> +    {
> +      return EFI_SECURITY_VIOLATION;
> +    }
> +
> +    //
> +    // The VariableSpeculationBarrier() call here is to ensure the above sanity
> +    // check for the EFI_VARIABLE_AUTHENTICATION_2 descriptor has been
> completed
> +    // before the execution of subsequent codes.
> +    //
> +    VariableSpeculationBarrier ();
> +    PayloadSize = DataSize - AUTHINFO2_SIZE (Data);
> +  } else {
> +    PayloadSize = DataSize;
> +  }
> +
> +  if ((UINTN)(~0) - PayloadSize < StrSize (VariableName)) {
> +    //
> +    // Prevent whole variable size overflow
> +    //
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  //
> +  //  The size of the VariableName, including the Unicode Null in bytes plus
> +  //  the DataSize is limited to maximum size of PcdGet32
> (PcdMaxHardwareErrorVariableSize)
> +  //  bytes for HwErrRec#### variable.
> +  //
> +  if ((Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD) ==
> EFI_VARIABLE_HARDWARE_ERROR_RECORD) {
> +    if (StrSize (VariableName) + PayloadSize >
> +        PcdGet32 (PcdMaxHardwareErrorVariableSize) - GetVariableHeaderSize
> (AuthFormat))
> +    {
> +      return EFI_INVALID_PARAMETER;
> +    }
> +  } else {
> +    //
> +    //  The size of the VariableName, including the Unicode Null in bytes plus
> +    //  the DataSize is limited to maximum size of Max(Auth|Volatile)VariableSize
> bytes.
> +    //
> +    if ((Attributes & VARIABLE_ATTRIBUTE_AT_AW) != 0) {
> +      if (StrSize (VariableName) + PayloadSize >
> +          mVariableModuleGlobal->MaxAuthVariableSize -
> +          GetVariableHeaderSize (AuthFormat))
> +      {
> +        DEBUG ((
> +          DEBUG_ERROR,
> +          "%a: Failed to set variable '%s' with Guid %g\n",
> +          __FUNCTION__,
> +          VariableName,
> +          VendorGuid
> +          ));
> +        DEBUG ((
> +          DEBUG_ERROR,
> +          "NameSize(0x%x) + PayloadSize(0x%x) > "
> +          "MaxAuthVariableSize(0x%x) - HeaderSize(0x%x)\n",
> +          StrSize (VariableName),
> +          PayloadSize,
> +          mVariableModuleGlobal->MaxAuthVariableSize,
> +          GetVariableHeaderSize (AuthFormat)
> +          ));
> +        return EFI_INVALID_PARAMETER;
> +      }
> +    } else if ((Attributes & EFI_VARIABLE_NON_VOLATILE) != 0) {
> +      if (StrSize (VariableName) + PayloadSize >
> +          mVariableModuleGlobal->MaxVariableSize - GetVariableHeaderSize
> (AuthFormat))
> +      {
> +        DEBUG ((
> +          DEBUG_ERROR,
> +          "%a: Failed to set variable '%s' with Guid %g\n",
> +          __FUNCTION__,
> +          VariableName,
> +          VendorGuid
> +          ));
> +        DEBUG ((
> +          DEBUG_ERROR,
> +          "NameSize(0x%x) + PayloadSize(0x%x) > "
> +          "MaxVariableSize(0x%x) - HeaderSize(0x%x)\n",
> +          StrSize (VariableName),
> +          PayloadSize,
> +          mVariableModuleGlobal->MaxVariableSize,
> +          GetVariableHeaderSize (AuthFormat)
> +          ));
> +        return EFI_INVALID_PARAMETER;
> +      }
> +    } else {
> +      if (StrSize (VariableName) + PayloadSize >
> +          mVariableModuleGlobal->MaxVolatileVariableSize -
> GetVariableHeaderSize (AuthFormat))
> +      {
> +        DEBUG ((
> +          DEBUG_ERROR,
> +          "%a: Failed to set variable '%s' with Guid %g\n",
> +          __FUNCTION__,
> +          VariableName,
> +          VendorGuid
> +          ));
> +        DEBUG ((
> +          DEBUG_ERROR,
> +          "NameSize(0x%x) + PayloadSize(0x%x) > "
> +          "MaxVolatileVariableSize(0x%x) - HeaderSize(0x%x)\n",
> +          StrSize (VariableName),
> +          PayloadSize,
> +          mVariableModuleGlobal->MaxVolatileVariableSize,
> +          GetVariableHeaderSize (AuthFormat)
> +          ));
> +        return EFI_INVALID_PARAMETER;
> +      }
> +    }
> +  }
> +
> +  //
> +  // Special Handling for MOR Lock variable.
> +  //
> +  Status = SetVariableCheckHandlerMor (VariableName, VendorGuid, Attributes,
> PayloadSize, (VOID *)((UINTN)Data + DataSize - PayloadSize));
> +  if (Status == EFI_ALREADY_STARTED) {
> +    //
> +    // EFI_ALREADY_STARTED means the SetVariable() action is handled inside of
> SetVariableCheckHandlerMor().
> +    // Variable driver can just return SUCCESS.
> +    //
> +    return EFI_SUCCESS;
> +  }
> +
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  Status = VarCheckLibSetVariableCheck (VariableName, VendorGuid, Attributes,
> PayloadSize, (VOID *)((UINTN)Data + DataSize - PayloadSize), mRequestSource);
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock);
> +
> +  //
> +  // Consider reentrant in MCA/INIT/NMI. It needs be reupdated.
> +  //
> +  if (1 < InterlockedIncrement (&mVariableModuleGlobal-
> >VariableGlobal.ReentrantState)) {
> +    Point = mVariableModuleGlobal->VariableGlobal.NonVolatileVariableBase;
> +    //
> +    // Parse non-volatile variable data and get last variable offset.
> +    //
> +    NextVariable = GetStartPointer ((VARIABLE_STORE_HEADER *)(UINTN)Point);
> +    while (IsValidVariableHeader (NextVariable, GetEndPointer
> ((VARIABLE_STORE_HEADER *)(UINTN)Point), AuthFormat)) {
> +      NextVariable = GetNextVariablePtr (NextVariable, AuthFormat);
> +    }
> +
> +    mVariableModuleGlobal->NonVolatileLastVariableOffset =
> (UINTN)NextVariable - (UINTN)Point;
> +  }
> +
> +  //
> +  // Check whether the input variable is already existed.
> +  //
> +  Status = FindVariable (VariableName, VendorGuid, &Variable,
> &mVariableModuleGlobal->VariableGlobal, TRUE);
> +  if (!EFI_ERROR (Status)) {
> +    if (((Variable.CurrPtr->Attributes & EFI_VARIABLE_RUNTIME_ACCESS) == 0)
> && AtRuntime ()) {
> +      Status = EFI_WRITE_PROTECTED;
> +      goto Done;
> +    }
> +
> +    if ((Attributes != 0) && ((Attributes & (~EFI_VARIABLE_APPEND_WRITE)) !=
> Variable.CurrPtr->Attributes)) {
> +      //
> +      // If a preexisting variable is rewritten with different attributes, SetVariable()
> shall not
> +      // modify the variable and shall return EFI_INVALID_PARAMETER. Two
> exceptions to this rule:
> +      // 1. No access attributes specified
> +      // 2. The only attribute differing is EFI_VARIABLE_APPEND_WRITE
> +      //
> +      Status = EFI_INVALID_PARAMETER;
> +      DEBUG ((DEBUG_INFO, "[Variable]: Rewritten a preexisting variable(0x%08x)
> with different attributes(0x%08x) - %g:%s\n", Variable.CurrPtr->Attributes,
> Attributes, VendorGuid, VariableName));
> +      goto Done;
> +    }
> +  }
> +
> +  if (!FeaturePcdGet (PcdUefiVariableDefaultLangDeprecate)) {
> +    //
> +    // Hook the operation of setting PlatformLangCodes/PlatformLang and
> LangCodes/Lang.
> +    //
> +    Status = AutoUpdateLangVariable (VariableName, Data, DataSize);
> +    if (EFI_ERROR (Status)) {
> +      //
> +      // The auto update operation failed, directly return to avoid inconsistency
> between PlatformLang and Lang.
> +      //
> +      goto Done;
> +    }
> +  }
> +
> +  if (mVariableModuleGlobal->VariableGlobal.AuthSupport) {
> +    Status = AuthVariableLibProcessVariable (VariableName, VendorGuid, Data,
> DataSize, Attributes);
> +  } else {
> +    Status = UpdateVariable (VariableName, VendorGuid, Data, DataSize,
> Attributes, 0, 0, &Variable, NULL);
> +  }
> +
> +Done:
> +  InterlockedDecrement (&mVariableModuleGlobal-
> >VariableGlobal.ReentrantState);
> +  ReleaseLockOnlyAtBootTime (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock);
> +
> +  if (!AtRuntime ()) {
> +    if (!EFI_ERROR (Status)) {
> +      SecureBootHook (
> +        VariableName,
> +        VendorGuid
> +        );
> +    }
> +  }
> +
> +  return Status;
> +}
> +
> +/**
> +
> +  This code returns information about the EFI variables.
> +
> +  Caution: This function may receive untrusted input.
> +  This function may be invoked in SMM mode. This function will do basic
> validation, before parse the data.
> +
> +  @param Attributes                     Attributes bitmask to specify the type of
> variables
> +                                        on which to return information.
> +  @param MaximumVariableStorageSize     Pointer to the maximum size of the
> storage space available
> +                                        for the EFI variables associated with the attributes
> specified.
> +  @param RemainingVariableStorageSize   Pointer to the remaining size of the
> storage space available
> +                                        for EFI variables associated with the attributes specified.
> +  @param MaximumVariableSize            Pointer to the maximum size of an
> individual EFI variables
> +                                        associated with the attributes specified.
> +
> +  @return EFI_SUCCESS                   Query successfully.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableServiceQueryVariableInfoInternal (
> +  IN  UINT32  Attributes,
> +  OUT UINT64  *MaximumVariableStorageSize,
> +  OUT UINT64  *RemainingVariableStorageSize,
> +  OUT UINT64  *MaximumVariableSize
> +  )
> +{
> +  VARIABLE_HEADER         *Variable;
> +  VARIABLE_HEADER         *NextVariable;
> +  UINT64                  VariableSize;
> +  VARIABLE_STORE_HEADER   *VariableStoreHeader;
> +  UINT64                  CommonVariableTotalSize;
> +  UINT64                  HwErrVariableTotalSize;
> +  EFI_STATUS              Status;
> +  VARIABLE_POINTER_TRACK  VariablePtrTrack;
> +
> +  CommonVariableTotalSize = 0;
> +  HwErrVariableTotalSize  = 0;
> +
> +  if ((Attributes & EFI_VARIABLE_NON_VOLATILE) == 0) {
> +    //
> +    // Query is Volatile related.
> +    //
> +    VariableStoreHeader = (VARIABLE_STORE_HEADER
> *)((UINTN)mVariableModuleGlobal->VariableGlobal.VolatileVariableBase);
> +  } else {
> +    //
> +    // Query is Non-Volatile related.
> +    //
> +    VariableStoreHeader = mNvVariableCache;
> +  }
> +
> +  //
> +  // Now let's fill *MaximumVariableStorageSize
> *RemainingVariableStorageSize
> +  // with the storage size (excluding the storage header size).
> +  //
> +  *MaximumVariableStorageSize = VariableStoreHeader->Size - sizeof
> (VARIABLE_STORE_HEADER);
> +
> +  //
> +  // Harware error record variable needs larger size.
> +  //
> +  if ((Attributes & (EFI_VARIABLE_NON_VOLATILE |
> EFI_VARIABLE_HARDWARE_ERROR_RECORD)) ==
> (EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_HARDWARE_ERROR_RECORD))
> {
> +    *MaximumVariableStorageSize = PcdGet32 (PcdHwErrStorageSize);
> +    *MaximumVariableSize        =  PcdGet32 (PcdMaxHardwareErrorVariableSize)
> -
> +                                  GetVariableHeaderSize (mVariableModuleGlobal-
> >VariableGlobal.AuthFormat);
> +  } else {
> +    if ((Attributes & EFI_VARIABLE_NON_VOLATILE) != 0) {
> +      if (AtRuntime ()) {
> +        *MaximumVariableStorageSize = mVariableModuleGlobal-
> >CommonRuntimeVariableSpace;
> +      } else {
> +        *MaximumVariableStorageSize = mVariableModuleGlobal-
> >CommonVariableSpace;
> +      }
> +    }
> +
> +    //
> +    // Let *MaximumVariableSize be Max(Auth|Volatile)VariableSize with the
> exception of the variable header size.
> +    //
> +    if ((Attributes & VARIABLE_ATTRIBUTE_AT_AW) != 0) {
> +      *MaximumVariableSize =  mVariableModuleGlobal->MaxAuthVariableSize -
> +                             GetVariableHeaderSize (mVariableModuleGlobal-
> >VariableGlobal.AuthFormat);
> +    } else if ((Attributes & EFI_VARIABLE_NON_VOLATILE) != 0) {
> +      *MaximumVariableSize =  mVariableModuleGlobal->MaxVariableSize -
> +                             GetVariableHeaderSize (mVariableModuleGlobal-
> >VariableGlobal.AuthFormat);
> +    } else {
> +      *MaximumVariableSize =   mVariableModuleGlobal-
> >MaxVolatileVariableSize -
> +                             GetVariableHeaderSize (mVariableModuleGlobal-
> >VariableGlobal.AuthFormat);
> +    }
> +  }
> +
> +  //
> +  // Point to the starting address of the variables.
> +  //
> +  Variable = GetStartPointer (VariableStoreHeader);
> +
> +  //
> +  // Now walk through the related variable store.
> +  //
> +  while (IsValidVariableHeader (
> +           Variable,
> +           GetEndPointer (VariableStoreHeader),
> +           mVariableModuleGlobal->VariableGlobal.AuthFormat
> +           ))
> +  {
> +    NextVariable = GetNextVariablePtr (Variable, mVariableModuleGlobal-
> >VariableGlobal.AuthFormat);
> +    VariableSize = (UINT64)(UINTN)NextVariable - (UINT64)(UINTN)Variable;
> +
> +    if (AtRuntime ()) {
> +      //
> +      // We don't take the state of the variables in mind
> +      // when calculating RemainingVariableStorageSize,
> +      // since the space occupied by variables not marked with
> +      // VAR_ADDED is not allowed to be reclaimed in Runtime.
> +      //
> +      if ((Variable->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD) ==
> EFI_VARIABLE_HARDWARE_ERROR_RECORD) {
> +        HwErrVariableTotalSize += VariableSize;
> +      } else {
> +        CommonVariableTotalSize += VariableSize;
> +      }
> +    } else {
> +      //
> +      // Only care about Variables with State VAR_ADDED, because
> +      // the space not marked as VAR_ADDED is reclaimable now.
> +      //
> +      if (Variable->State == VAR_ADDED) {
> +        if ((Variable->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
> == EFI_VARIABLE_HARDWARE_ERROR_RECORD) {
> +          HwErrVariableTotalSize += VariableSize;
> +        } else {
> +          CommonVariableTotalSize += VariableSize;
> +        }
> +      } else if (Variable->State == (VAR_IN_DELETED_TRANSITION & VAR_ADDED))
> {
> +        //
> +        // If it is a IN_DELETED_TRANSITION variable,
> +        // and there is not also a same ADDED one at the same time,
> +        // this IN_DELETED_TRANSITION variable is valid.
> +        //
> +        VariablePtrTrack.StartPtr = GetStartPointer (VariableStoreHeader);
> +        VariablePtrTrack.EndPtr   = GetEndPointer (VariableStoreHeader);
> +        Status                    = FindVariableEx (
> +                                      GetVariableNamePtr (Variable, mVariableModuleGlobal-
> >VariableGlobal.AuthFormat),
> +                                      GetVendorGuidPtr (Variable, mVariableModuleGlobal-
> >VariableGlobal.AuthFormat),
> +                                      FALSE,
> +                                      &VariablePtrTrack,
> +                                      mVariableModuleGlobal->VariableGlobal.AuthFormat
> +                                      );
> +        if (!EFI_ERROR (Status) && (VariablePtrTrack.CurrPtr->State !=
> VAR_ADDED)) {
> +          if ((Variable->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
> == EFI_VARIABLE_HARDWARE_ERROR_RECORD) {
> +            HwErrVariableTotalSize += VariableSize;
> +          } else {
> +            CommonVariableTotalSize += VariableSize;
> +          }
> +        }
> +      }
> +    }
> +
> +    //
> +    // Go to the next one.
> +    //
> +    Variable = NextVariable;
> +  }
> +
> +  if ((Attributes  & EFI_VARIABLE_HARDWARE_ERROR_RECORD) ==
> EFI_VARIABLE_HARDWARE_ERROR_RECORD) {
> +    *RemainingVariableStorageSize = *MaximumVariableStorageSize -
> HwErrVariableTotalSize;
> +  } else {
> +    if (*MaximumVariableStorageSize < CommonVariableTotalSize) {
> +      *RemainingVariableStorageSize = 0;
> +    } else {
> +      *RemainingVariableStorageSize = *MaximumVariableStorageSize -
> CommonVariableTotalSize;
> +    }
> +  }
> +
> +  if (*RemainingVariableStorageSize < GetVariableHeaderSize
> (mVariableModuleGlobal->VariableGlobal.AuthFormat)) {
> +    *MaximumVariableSize = 0;
> +  } else if ((*RemainingVariableStorageSize - GetVariableHeaderSize
> (mVariableModuleGlobal->VariableGlobal.AuthFormat)) <
> +             *MaximumVariableSize
> +             )
> +  {
> +    *MaximumVariableSize = *RemainingVariableStorageSize -
> +                           GetVariableHeaderSize (mVariableModuleGlobal-
> >VariableGlobal.AuthFormat);
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +
> +  This code returns information about the EFI variables.
> +
> +  Caution: This function may receive untrusted input.
> +  This function may be invoked in SMM mode. This function will do basic
> validation, before parse the data.
> +
> +  @param Attributes                     Attributes bitmask to specify the type of
> variables
> +                                        on which to return information.
> +  @param MaximumVariableStorageSize     Pointer to the maximum size of the
> storage space available
> +                                        for the EFI variables associated with the attributes
> specified.
> +  @param RemainingVariableStorageSize   Pointer to the remaining size of the
> storage space available
> +                                        for EFI variables associated with the attributes specified.
> +  @param MaximumVariableSize            Pointer to the maximum size of an
> individual EFI variables
> +                                        associated with the attributes specified.
> +
> +  @return EFI_INVALID_PARAMETER         An invalid combination of attribute
> bits was supplied.
> +  @return EFI_SUCCESS                   Query successfully.
> +  @return EFI_UNSUPPORTED               The attribute is not supported on this
> platform.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableServiceQueryVariableInfo (
> +  IN  UINT32  Attributes,
> +  OUT UINT64  *MaximumVariableStorageSize,
> +  OUT UINT64  *RemainingVariableStorageSize,
> +  OUT UINT64  *MaximumVariableSize
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  if ((MaximumVariableStorageSize == NULL) || (RemainingVariableStorageSize
> == NULL) || (MaximumVariableSize == NULL) || (Attributes == 0)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if ((Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS) != 0) {
> +    //
> +    //  Deprecated attribute, make this check as highest priority.
> +    //
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  if ((Attributes & EFI_VARIABLE_ATTRIBUTES_MASK) == 0) {
> +    //
> +    // Make sure the Attributes combination is supported by the platform.
> +    //
> +    return EFI_UNSUPPORTED;
> +  } else if ((Attributes & EFI_VARIABLE_ATTRIBUTES_MASK) ==
> EFI_VARIABLE_NON_VOLATILE) {
> +    //
> +    // Only EFI_VARIABLE_NON_VOLATILE attribute is invalid
> +    //
> +    return EFI_INVALID_PARAMETER;
> +  } else if ((Attributes & (EFI_VARIABLE_RUNTIME_ACCESS |
> EFI_VARIABLE_BOOTSERVICE_ACCESS)) == EFI_VARIABLE_RUNTIME_ACCESS) {
> +    //
> +    // Make sure if runtime bit is set, boot service bit is set also.
> +    //
> +    return EFI_INVALID_PARAMETER;
> +  } else if (AtRuntime () && ((Attributes & EFI_VARIABLE_RUNTIME_ACCESS) ==
> 0)) {
> +    //
> +    // Make sure RT Attribute is set if we are in Runtime phase.
> +    //
> +    return EFI_INVALID_PARAMETER;
> +  } else if ((Attributes & (EFI_VARIABLE_NON_VOLATILE |
> EFI_VARIABLE_HARDWARE_ERROR_RECORD)) ==
> EFI_VARIABLE_HARDWARE_ERROR_RECORD) {
> +    //
> +    // Make sure Hw Attribute is set with NV.
> +    //
> +    return EFI_INVALID_PARAMETER;
> +  } else if ((Attributes & VARIABLE_ATTRIBUTE_AT_AW) != 0) {
> +    if (!mVariableModuleGlobal->VariableGlobal.AuthSupport) {
> +      //
> +      // Not support authenticated variable write.
> +      //
> +      return EFI_UNSUPPORTED;
> +    }
> +  } else if ((Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD) != 0) {
> +    if (PcdGet32 (PcdHwErrStorageSize) == 0) {
> +      //
> +      // Not support harware error record variable variable.
> +      //
> +      return EFI_UNSUPPORTED;
> +    }
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock);
> +
> +  Status = VariableServiceQueryVariableInfoInternal (
> +             Attributes,
> +             MaximumVariableStorageSize,
> +             RemainingVariableStorageSize,
> +             MaximumVariableSize
> +             );
> +
> +  ReleaseLockOnlyAtBootTime (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock);
> +  return Status;
> +}
> +
> +/**
> +  This function reclaims variable storage if free size is below the threshold.
> +
> +  Caution: This function may be invoked at SMM mode.
> +  Care must be taken to make sure not security issue.
> +
> +**/
> +VOID
> +ReclaimForOS (
> +  VOID
> +  )
> +{
> +  EFI_STATUS      Status;
> +  UINTN           RemainingCommonRuntimeVariableSpace;
> +  UINTN           RemainingHwErrVariableSpace;
> +  STATIC BOOLEAN  Reclaimed;
> +
> +  //
> +  // This function will be called only once at EndOfDxe or ReadyToBoot event.
> +  //
> +  if (Reclaimed) {
> +    return;
> +  }
> +
> +  Reclaimed = TRUE;
> +
> +  Status = EFI_SUCCESS;
> +
> +  if (mVariableModuleGlobal->CommonRuntimeVariableSpace <
> mVariableModuleGlobal->CommonVariableTotalSize) {
> +    RemainingCommonRuntimeVariableSpace = 0;
> +  } else {
> +    RemainingCommonRuntimeVariableSpace = mVariableModuleGlobal-
> >CommonRuntimeVariableSpace - mVariableModuleGlobal-
> >CommonVariableTotalSize;
> +  }
> +
> +  RemainingHwErrVariableSpace = PcdGet32 (PcdHwErrStorageSize) -
> mVariableModuleGlobal->HwErrVariableTotalSize;
> +
> +  //
> +  // Check if the free area is below a threshold.
> +  //
> +  if (((RemainingCommonRuntimeVariableSpace < mVariableModuleGlobal-
> >MaxVariableSize) ||
> +       (RemainingCommonRuntimeVariableSpace < mVariableModuleGlobal-
> >MaxAuthVariableSize)) ||
> +      ((PcdGet32 (PcdHwErrStorageSize) != 0) &&
> +       (RemainingHwErrVariableSpace < PcdGet32
> (PcdMaxHardwareErrorVariableSize))))
> +  {
> +    Status = Reclaim (
> +               mVariableModuleGlobal->VariableGlobal.NonVolatileVariableBase,
> +               &mVariableModuleGlobal->NonVolatileLastVariableOffset,
> +               FALSE,
> +               NULL,
> +               NULL,
> +               0
> +               );
> +    ASSERT_EFI_ERROR (Status);
> +  }
> +}
> +
> +/**
> +  Get maximum variable size, covering both non-volatile and volatile variables.
> +
> +  @return Maximum variable size.
> +
> +**/
> +UINTN
> +GetMaxVariableSize (
> +  VOID
> +  )
> +{
> +  UINTN  MaxVariableSize;
> +
> +  MaxVariableSize = GetNonVolatileMaxVariableSize ();
> +  //
> +  // The condition below fails implicitly if PcdMaxVolatileVariableSize equals
> +  // the default zero value.
> +  //
> +  if (MaxVariableSize < PcdGet32 (PcdMaxVolatileVariableSize)) {
> +    MaxVariableSize = PcdGet32 (PcdMaxVolatileVariableSize);
> +  }
> +
> +  return MaxVariableSize;
> +}
> +
> +/**
> +  Flush the HOB variable to flash.
> +
> +  @param[in] VariableName       Name of variable has been updated or deleted.
> +  @param[in] VendorGuid         Guid of variable has been updated or deleted.
> +
> +**/
> +VOID
> +FlushHobVariableToFlash (
> +  IN CHAR16    *VariableName,
> +  IN EFI_GUID  *VendorGuid
> +  )
> +{
> +  EFI_STATUS              Status;
> +  VARIABLE_STORE_HEADER   *VariableStoreHeader;
> +  VARIABLE_HEADER         *Variable;
> +  VOID                    *VariableData;
> +  VARIABLE_POINTER_TRACK  VariablePtrTrack;
> +  BOOLEAN                 ErrorFlag;
> +  BOOLEAN                 AuthFormat;
> +
> +  ErrorFlag  = FALSE;
> +  AuthFormat = mVariableModuleGlobal->VariableGlobal.AuthFormat;
> +
> +  //
> +  // Flush the HOB variable to flash.
> +  //
> +  if (mVariableModuleGlobal->VariableGlobal.HobVariableBase != 0) {
> +    VariableStoreHeader = (VARIABLE_STORE_HEADER
> *)(UINTN)mVariableModuleGlobal->VariableGlobal.HobVariableBase;
> +    //
> +    // Set HobVariableBase to 0, it can avoid SetVariable to call back.
> +    //
> +    mVariableModuleGlobal->VariableGlobal.HobVariableBase = 0;
> +    for ( Variable = GetStartPointer (VariableStoreHeader)
> +          ; IsValidVariableHeader (Variable, GetEndPointer (VariableStoreHeader),
> AuthFormat)
> +          ; Variable = GetNextVariablePtr (Variable, AuthFormat)
> +          )
> +    {
> +      if (Variable->State != VAR_ADDED) {
> +        //
> +        // The HOB variable has been set to DELETED state in local.
> +        //
> +        continue;
> +      }
> +
> +      ASSERT ((Variable->Attributes & EFI_VARIABLE_NON_VOLATILE) != 0);
> +      if ((VendorGuid == NULL) || (VariableName == NULL) ||
> +          !CompareGuid (VendorGuid, GetVendorGuidPtr (Variable, AuthFormat)) ||
> +          (StrCmp (VariableName, GetVariableNamePtr (Variable, AuthFormat)) !=
> 0))
> +      {
> +        VariableData = GetVariableDataPtr (Variable, AuthFormat);
> +        FindVariable (
> +          GetVariableNamePtr (Variable, AuthFormat),
> +          GetVendorGuidPtr (Variable, AuthFormat),
> +          &VariablePtrTrack,
> +          &mVariableModuleGlobal->VariableGlobal,
> +          FALSE
> +          );
> +        Status = UpdateVariable (
> +                   GetVariableNamePtr (Variable, AuthFormat),
> +                   GetVendorGuidPtr (Variable, AuthFormat),
> +                   VariableData,
> +                   DataSizeOfVariable (Variable, AuthFormat),
> +                   Variable->Attributes,
> +                   0,
> +                   0,
> +                   &VariablePtrTrack,
> +                   NULL
> +                   );
> +        DEBUG ((
> +          DEBUG_INFO,
> +          "Variable driver flush the HOB variable to flash: %g %s %r\n",
> +          GetVendorGuidPtr (Variable, AuthFormat),
> +          GetVariableNamePtr (Variable, AuthFormat),
> +          Status
> +          ));
> +      } else {
> +        //
> +        // The updated or deleted variable is matched with this HOB variable.
> +        // Don't break here because we will try to set other HOB variables
> +        // since this variable could be set successfully.
> +        //
> +        Status = EFI_SUCCESS;
> +      }
> +
> +      if (!EFI_ERROR (Status)) {
> +        //
> +        // If set variable successful, or the updated or deleted variable is matched
> with the HOB variable,
> +        // set the HOB variable to DELETED state in local.
> +        //
> +        DEBUG ((
> +          DEBUG_INFO,
> +          "Variable driver set the HOB variable to DELETED state in local: %g %s\n",
> +          GetVendorGuidPtr (Variable, AuthFormat),
> +          GetVariableNamePtr (Variable, AuthFormat)
> +          ));
> +        Variable->State &= VAR_DELETED;
> +      } else {
> +        ErrorFlag = TRUE;
> +      }
> +    }
> +
> +    if (mVariableModuleGlobal-
> >VariableGlobal.VariableRuntimeCacheContext.VariableRuntimeHobCache.Stor
> e != NULL) {
> +      Status =  SynchronizeRuntimeVariableCache (
> +                  &mVariableModuleGlobal-
> >VariableGlobal.VariableRuntimeCacheContext.VariableRuntimeHobCache,
> +                  0,
> +                  mVariableModuleGlobal-
> >VariableGlobal.VariableRuntimeCacheContext.VariableRuntimeHobCache.Stor
> e->Size
> +                  );
> +      ASSERT_EFI_ERROR (Status);
> +    }
> +
> +    if (ErrorFlag) {
> +      //
> +      // We still have HOB variable(s) not flushed in flash.
> +      //
> +      mVariableModuleGlobal->VariableGlobal.HobVariableBase =
> (EFI_PHYSICAL_ADDRESS)(UINTN)VariableStoreHeader;
> +    } else {
> +      //
> +      // All HOB variables have been flushed in flash.
> +      //
> +      DEBUG ((DEBUG_INFO, "Variable driver: all HOB variables have been
> flushed in flash.\n"));
> +      if (mVariableModuleGlobal-
> >VariableGlobal.VariableRuntimeCacheContext.HobFlushComplete != NULL) {
> +        *(mVariableModuleGlobal-
> >VariableGlobal.VariableRuntimeCacheContext.HobFlushComplete) = TRUE;
> +      }
> +
> +      if (!AtRuntime ()) {
> +        FreePool ((VOID *)VariableStoreHeader);
> +      }
> +    }
> +  }
> +}
> +
> +/**
> +  Initializes variable write service.
> +
> +  @retval EFI_SUCCESS          Function successfully executed.
> +  @retval Others               Fail to initialize the variable service.
> +
> +**/
> +EFI_STATUS
> +VariableWriteServiceInitialize (
> +  VOID
> +  )
> +{
> +  EFI_STATUS               Status;
> +  UINTN                    Index;
> +  UINT8                    Data;
> +  VARIABLE_ENTRY_PROPERTY  *VariableEntry;
> +
> +  AcquireLockOnlyAtBootTime (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock);
> +
> +  //
> +  // Check if the free area is really free.
> +  //
> +  for (Index = mVariableModuleGlobal->NonVolatileLastVariableOffset; Index <
> mNvVariableCache->Size; Index++) {
> +    Data = ((UINT8 *)mNvVariableCache)[Index];
> +    if (Data != 0xff) {
> +      //
> +      // There must be something wrong in variable store, do reclaim operation.
> +      //
> +      Status = Reclaim (
> +                 mVariableModuleGlobal->VariableGlobal.NonVolatileVariableBase,
> +                 &mVariableModuleGlobal->NonVolatileLastVariableOffset,
> +                 FALSE,
> +                 NULL,
> +                 NULL,
> +                 0
> +                 );
> +      if (EFI_ERROR (Status)) {
> +        ReleaseLockOnlyAtBootTime (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock);
> +        return Status;
> +      }
> +
> +      break;
> +    }
> +  }
> +
> +  FlushHobVariableToFlash (NULL, NULL);
> +
> +  Status = EFI_SUCCESS;
> +  ZeroMem (&mAuthContextOut, sizeof (mAuthContextOut));
> +  if (mVariableModuleGlobal->VariableGlobal.AuthFormat) {
> +    //
> +    // Authenticated variable initialize.
> +    //
> +    mAuthContextIn.StructSize          = sizeof (AUTH_VAR_LIB_CONTEXT_IN);
> +    mAuthContextIn.MaxAuthVariableSize =  mVariableModuleGlobal-
> >MaxAuthVariableSize -
> +                                         GetVariableHeaderSize (mVariableModuleGlobal-
> >VariableGlobal.AuthFormat);
> +    Status = AuthVariableLibInitialize (&mAuthContextIn, &mAuthContextOut);
> +    if (!EFI_ERROR (Status)) {
> +      DEBUG ((DEBUG_INFO, "Variable driver will work with auth variable
> support!\n"));
> +      mVariableModuleGlobal->VariableGlobal.AuthSupport = TRUE;
> +      if (mAuthContextOut.AuthVarEntry != NULL) {
> +        for (Index = 0; Index < mAuthContextOut.AuthVarEntryCount; Index++) {
> +          VariableEntry = &mAuthContextOut.AuthVarEntry[Index];
> +          Status        = VarCheckLibVariablePropertySet (
> +                            VariableEntry->Name,
> +                            VariableEntry->Guid,
> +                            &VariableEntry->VariableProperty
> +                            );
> +          ASSERT_EFI_ERROR (Status);
> +        }
> +      }
> +    } else if (Status == EFI_UNSUPPORTED) {
> +      DEBUG ((DEBUG_INFO, "NOTICE - AuthVariableLibInitialize() returns %r!\n",
> Status));
> +      DEBUG ((DEBUG_INFO, "Variable driver will continue to work without auth
> variable support!\n"));
> +      mVariableModuleGlobal->VariableGlobal.AuthSupport = FALSE;
> +      Status                                            = EFI_SUCCESS;
> +    }
> +  }
> +
> +  if (!EFI_ERROR (Status)) {
> +    for (Index = 0; Index < ARRAY_SIZE (mVariableEntryProperty); Index++) {
> +      VariableEntry = &mVariableEntryProperty[Index];
> +      Status        = VarCheckLibVariablePropertySet (VariableEntry->Name,
> VariableEntry->Guid, &VariableEntry->VariableProperty);
> +      ASSERT_EFI_ERROR (Status);
> +    }
> +  }
> +
> +  ReleaseLockOnlyAtBootTime (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock);
> +
> +  //
> +  // Initialize MOR Lock variable.
> +  //
> +  MorLockInit ();
> +
> +  return Status;
> +}
> +
> +/**
> +  Convert normal variable storage to the allocated auth variable storage.
> +
> +  @param[in]  NormalVarStorage  Pointer to the normal variable storage
> header
> +
> +  @retval the allocated auth variable storage
> +**/
> +VOID *
> +ConvertNormalVarStorageToAuthVarStorage (
> +  VARIABLE_STORE_HEADER  *NormalVarStorage
> +  )
> +{
> +  VARIABLE_HEADER                *StartPtr;
> +  UINT8                          *NextPtr;
> +  VARIABLE_HEADER                *EndPtr;
> +  UINTN                          AuthVarStorageSize;
> +  AUTHENTICATED_VARIABLE_HEADER  *AuthStartPtr;
> +  VARIABLE_STORE_HEADER          *AuthVarStorage;
> +
> +  AuthVarStorageSize = sizeof (VARIABLE_STORE_HEADER);
> +  //
> +  // Set AuthFormat as FALSE for normal variable storage
> +  //
> +  mVariableModuleGlobal->VariableGlobal.AuthFormat = FALSE;
> +
> +  //
> +  // Calculate Auth Variable Storage Size
> +  //
> +  StartPtr = GetStartPointer (NormalVarStorage);
> +  EndPtr   = GetEndPointer (NormalVarStorage);
> +  while (StartPtr < EndPtr) {
> +    if (StartPtr->State == VAR_ADDED) {
> +      AuthVarStorageSize  = HEADER_ALIGN (AuthVarStorageSize);
> +      AuthVarStorageSize += sizeof (AUTHENTICATED_VARIABLE_HEADER);
> +      AuthVarStorageSize += StartPtr->NameSize + GET_PAD_SIZE (StartPtr-
> >NameSize);
> +      AuthVarStorageSize += StartPtr->DataSize + GET_PAD_SIZE (StartPtr-
> >DataSize);
> +    }
> +
> +    StartPtr = GetNextVariablePtr (StartPtr, mVariableModuleGlobal-
> >VariableGlobal.AuthFormat);
> +  }
> +
> +  //
> +  // Allocate Runtime memory for Auth Variable Storage
> +  //
> +  AuthVarStorage = AllocateRuntimeZeroPool (AuthVarStorageSize);
> +  ASSERT (AuthVarStorage != NULL);
> +  if (AuthVarStorage == NULL) {
> +    return NULL;
> +  }
> +
> +  //
> +  // Copy Variable from Normal storage to Auth storage
> +  //
> +  StartPtr     = GetStartPointer (NormalVarStorage);
> +  EndPtr       = GetEndPointer (NormalVarStorage);
> +  AuthStartPtr = (AUTHENTICATED_VARIABLE_HEADER *)GetStartPointer
> (AuthVarStorage);
> +  while (StartPtr < EndPtr) {
> +    if (StartPtr->State == VAR_ADDED) {
> +      AuthStartPtr = (AUTHENTICATED_VARIABLE_HEADER *)HEADER_ALIGN
> (AuthStartPtr);
> +      //
> +      // Copy Variable Header
> +      //
> +      AuthStartPtr->StartId    = StartPtr->StartId;
> +      AuthStartPtr->State      = StartPtr->State;
> +      AuthStartPtr->Attributes = StartPtr->Attributes;
> +      AuthStartPtr->NameSize   = StartPtr->NameSize;
> +      AuthStartPtr->DataSize   = StartPtr->DataSize;
> +      CopyGuid (&AuthStartPtr->VendorGuid, &StartPtr->VendorGuid);
> +      //
> +      // Copy Variable Name
> +      //
> +      NextPtr = (UINT8 *)(AuthStartPtr + 1);
> +      CopyMem (
> +        NextPtr,
> +        GetVariableNamePtr (StartPtr, mVariableModuleGlobal-
> >VariableGlobal.AuthFormat),
> +        AuthStartPtr->NameSize
> +        );
> +      //
> +      // Copy Variable Data
> +      //
> +      NextPtr = NextPtr + AuthStartPtr->NameSize + GET_PAD_SIZE (AuthStartPtr-
> >NameSize);
> +      CopyMem (NextPtr, GetVariableDataPtr (StartPtr, mVariableModuleGlobal-
> >VariableGlobal.AuthFormat), AuthStartPtr->DataSize);
> +      //
> +      // Go to next variable
> +      //
> +      AuthStartPtr = (AUTHENTICATED_VARIABLE_HEADER *)(NextPtr +
> AuthStartPtr->DataSize + GET_PAD_SIZE (AuthStartPtr->DataSize));
> +    }
> +
> +    StartPtr = GetNextVariablePtr (StartPtr, mVariableModuleGlobal-
> >VariableGlobal.AuthFormat);
> +  }
> +
> +  //
> +  // Update Auth Storage Header
> +  //
> +  AuthVarStorage->Format = NormalVarStorage->Format;
> +  AuthVarStorage->State  = NormalVarStorage->State;
> +  AuthVarStorage->Size   = (UINT32)((UINTN)AuthStartPtr -
> (UINTN)AuthVarStorage);
> +  CopyGuid (&AuthVarStorage->Signature, &gEfiAuthenticatedVariableGuid);
> +  ASSERT (AuthVarStorage->Size <= AuthVarStorageSize);
> +
> +  //
> +  // Restore AuthFormat
> +  //
> +  mVariableModuleGlobal->VariableGlobal.AuthFormat = TRUE;
> +  return AuthVarStorage;
> +}
> +
> +/**
> +  Get HOB variable store.
> +
> +  @param[in] VariableGuid       NV variable store signature.
> +
> +  @retval EFI_SUCCESS           Function successfully executed.
> +  @retval EFI_OUT_OF_RESOURCES  Fail to allocate enough memory resource.
> +
> +**/
> +EFI_STATUS
> +GetHobVariableStore (
> +  IN EFI_GUID  *VariableGuid
> +  )
> +{
> +  VARIABLE_STORE_HEADER  *VariableStoreHeader;
> +  UINT64                 VariableStoreLength;
> +  EFI_HOB_GUID_TYPE      *GuidHob;
> +  BOOLEAN                NeedConvertNormalToAuth;
> +
> +  //
> +  // Make sure there is no more than one Variable HOB.
> +  //
> +  DEBUG_CODE_BEGIN ();
> +  GuidHob = GetFirstGuidHob (&gEfiAuthenticatedVariableGuid);
> +  if (GuidHob != NULL) {
> +    if ((GetNextGuidHob (&gEfiAuthenticatedVariableGuid, GET_NEXT_HOB
> (GuidHob)) != NULL)) {
> +      DEBUG ((DEBUG_ERROR, "ERROR: Found two Auth Variable HOBs\n"));
> +      ASSERT (FALSE);
> +    } else if (GetFirstGuidHob (&gEfiVariableGuid) != NULL) {
> +      DEBUG ((DEBUG_ERROR, "ERROR: Found one Auth + one Normal Variable
> HOBs\n"));
> +      ASSERT (FALSE);
> +    }
> +  } else {
> +    GuidHob = GetFirstGuidHob (&gEfiVariableGuid);
> +    if (GuidHob != NULL) {
> +      if ((GetNextGuidHob (&gEfiVariableGuid, GET_NEXT_HOB (GuidHob)) !=
> NULL)) {
> +        DEBUG ((DEBUG_ERROR, "ERROR: Found two Normal Variable HOBs\n"));
> +        ASSERT (FALSE);
> +      }
> +    }
> +  }
> +
> +  DEBUG_CODE_END ();
> +
> +  //
> +  // Combinations supported:
> +  // 1. Normal NV variable store +
> +  //    Normal HOB variable store
> +  // 2. Auth NV variable store +
> +  //    Auth HOB variable store
> +  // 3. Auth NV variable store +
> +  //    Normal HOB variable store (code will convert it to Auth Format)
> +  //
> +  NeedConvertNormalToAuth = FALSE;
> +  GuidHob                 = GetFirstGuidHob (VariableGuid);
> +  if ((GuidHob == NULL) && (VariableGuid == &gEfiAuthenticatedVariableGuid)) {
> +    //
> +    // Try getting it from normal variable HOB
> +    //
> +    GuidHob                 = GetFirstGuidHob (&gEfiVariableGuid);
> +    NeedConvertNormalToAuth = TRUE;
> +  }
> +
> +  if (GuidHob != NULL) {
> +    VariableStoreHeader = GET_GUID_HOB_DATA (GuidHob);
> +    VariableStoreLength = GuidHob->Header.HobLength - sizeof
> (EFI_HOB_GUID_TYPE);
> +    if (GetVariableStoreStatus (VariableStoreHeader) == EfiValid) {
> +      if (!NeedConvertNormalToAuth) {
> +        mVariableModuleGlobal->VariableGlobal.HobVariableBase =
> (EFI_PHYSICAL_ADDRESS)(UINTN)AllocateRuntimeCopyPool
> ((UINTN)VariableStoreLength, (VOID *)VariableStoreHeader);
> +      } else {
> +        mVariableModuleGlobal->VariableGlobal.HobVariableBase =
> (EFI_PHYSICAL_ADDRESS)(UINTN)ConvertNormalVarStorageToAuthVarStorage
> ((VOID *)VariableStoreHeader);
> +      }
> +
> +      if (mVariableModuleGlobal->VariableGlobal.HobVariableBase == 0) {
> +        return EFI_OUT_OF_RESOURCES;
> +      }
> +    } else {
> +      DEBUG ((DEBUG_ERROR, "HOB Variable Store header is corrupted!\n"));
> +    }
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Initializes variable store area for non-volatile and volatile variable.
> +
> +  @retval EFI_SUCCESS           Function successfully executed.
> +  @retval EFI_OUT_OF_RESOURCES  Fail to allocate enough memory resource.
> +
> +**/
> +EFI_STATUS
> +VariableCommonInitialize (
> +  VOID
> +  )
> +{
> +  EFI_STATUS             Status;
> +  VARIABLE_STORE_HEADER  *VolatileVariableStore;
> +  UINTN                  ScratchSize;
> +  EFI_GUID               *VariableGuid;
> +
> +  //
> +  // Allocate runtime memory for variable driver global structure.
> +  //
> +  mVariableModuleGlobal = AllocateRuntimeZeroPool (sizeof
> (VARIABLE_MODULE_GLOBAL));
> +  if (mVariableModuleGlobal == NULL) {
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +
> +  InitializeLock (&mVariableModuleGlobal-
> >VariableGlobal.VariableServicesLock, TPL_NOTIFY);
> +
> +  //
> +  // Init non-volatile variable store.
> +  //
> +  Status = InitNonVolatileVariableStore ();
> +  if (EFI_ERROR (Status)) {
> +    FreePool (mVariableModuleGlobal);
> +    return Status;
> +  }
> +
> +  //
> +  // mVariableModuleGlobal->VariableGlobal.AuthFormat
> +  // has been initialized in InitNonVolatileVariableStore().
> +  //
> +  if (mVariableModuleGlobal->VariableGlobal.AuthFormat) {
> +    DEBUG ((DEBUG_INFO, "Variable driver will work with auth variable
> format!\n"));
> +    //
> +    // Set AuthSupport to FALSE first, VariableWriteServiceInitialize() will initialize
> it.
> +    //
> +    mVariableModuleGlobal->VariableGlobal.AuthSupport = FALSE;
> +    VariableGuid                                      = &gEfiAuthenticatedVariableGuid;
> +  } else {
> +    DEBUG ((DEBUG_INFO, "Variable driver will work without auth variable
> support!\n"));
> +    mVariableModuleGlobal->VariableGlobal.AuthSupport = FALSE;
> +    VariableGuid                                      = &gEfiVariableGuid;
> +  }
> +
> +  //
> +  // Get HOB variable store.
> +  //
> +  Status = GetHobVariableStore (VariableGuid);
> +  if (EFI_ERROR (Status)) {
> +    if (mNvFvHeaderCache != NULL) {
> +      FreePool (mNvFvHeaderCache);
> +    }
> +
> +    FreePool (mVariableModuleGlobal);
> +    return Status;
> +  }
> +
> +  mVariableModuleGlobal->MaxVolatileVariableSize = ((PcdGet32
> (PcdMaxVolatileVariableSize) != 0) ?
> +                                                    PcdGet32 (PcdMaxVolatileVariableSize) :
> +                                                    mVariableModuleGlobal->MaxVariableSize
> +                                                    );
> +  //
> +  // Allocate memory for volatile variable store, note that there is a scratch
> space to store scratch data.
> +  //
> +  ScratchSize                              = GetMaxVariableSize () * 2;
> +  mVariableModuleGlobal->ScratchBufferSize = ScratchSize;
> +  VolatileVariableStore                    = AllocateRuntimePool (PcdGet32
> (PcdVariableStoreSize) + ScratchSize);
> +  if (VolatileVariableStore == NULL) {
> +    if (mVariableModuleGlobal->VariableGlobal.HobVariableBase != 0) {
> +      FreePool ((VOID *)(UINTN)mVariableModuleGlobal-
> >VariableGlobal.HobVariableBase);
> +    }
> +
> +    if (mNvFvHeaderCache != NULL) {
> +      FreePool (mNvFvHeaderCache);
> +    }
> +
> +    FreePool (mVariableModuleGlobal);
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +
> +  SetMem (VolatileVariableStore, PcdGet32 (PcdVariableStoreSize) + ScratchSize,
> 0xff);
> +
> +  //
> +  // Initialize Variable Specific Data.
> +  //
> +  mVariableModuleGlobal->VariableGlobal.VolatileVariableBase =
> (EFI_PHYSICAL_ADDRESS)(UINTN)VolatileVariableStore;
> +  mVariableModuleGlobal->VolatileLastVariableOffset          =
> (UINTN)GetStartPointer (VolatileVariableStore) - (UINTN)VolatileVariableStore;
> +
> +  CopyGuid (&VolatileVariableStore->Signature, VariableGuid);
> +  VolatileVariableStore->Size      = PcdGet32 (PcdVariableStoreSize);
> +  VolatileVariableStore->Format    = VARIABLE_STORE_FORMATTED;
> +  VolatileVariableStore->State     = VARIABLE_STORE_HEALTHY;
> +  VolatileVariableStore->Reserved  = 0;
> +  VolatileVariableStore->Reserved1 = 0;
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Get the proper fvb handle and/or fvb protocol by the given Flash address.
> +
> +  @param[in]  Address       The Flash address.
> +  @param[out] FvbHandle     In output, if it is not NULL, it points to the proper
> FVB handle.
> +  @param[out] FvbProtocol   In output, if it is not NULL, it points to the proper
> FVB protocol.
> +
> +**/
> +EFI_STATUS
> +GetFvbInfoByAddress (
> +  IN  EFI_PHYSICAL_ADDRESS                Address,
> +  OUT EFI_HANDLE                          *FvbHandle OPTIONAL,
> +  OUT EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  **FvbProtocol OPTIONAL
> +  )
> +{
> +  EFI_STATUS                          Status;
> +  EFI_HANDLE                          *HandleBuffer;
> +  UINTN                               HandleCount;
> +  UINTN                               Index;
> +  EFI_PHYSICAL_ADDRESS                FvbBaseAddress;
> +  EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  *Fvb;
> +  EFI_FVB_ATTRIBUTES_2                Attributes;
> +  UINTN                               BlockSize;
> +  UINTN                               NumberOfBlocks;
> +
> +  HandleBuffer = NULL;
> +  //
> +  // Get all FVB handles.
> +  //
> +  Status = GetFvbCountAndBuffer (&HandleCount, &HandleBuffer);
> +  if (EFI_ERROR (Status)) {
> +    return EFI_NOT_FOUND;
> +  }
> +
> +  //
> +  // Get the FVB to access variable store.
> +  //
> +  Fvb = NULL;
> +  for (Index = 0; Index < HandleCount; Index += 1, Status = EFI_NOT_FOUND,
> Fvb = NULL) {
> +    Status = GetFvbByHandle (HandleBuffer[Index], &Fvb);
> +    if (EFI_ERROR (Status)) {
> +      Status = EFI_NOT_FOUND;
> +      break;
> +    }
> +
> +    //
> +    // Ensure this FVB protocol supported Write operation.
> +    //
> +    Status = Fvb->GetAttributes (Fvb, &Attributes);
> +    if (EFI_ERROR (Status) || ((Attributes & EFI_FVB2_WRITE_STATUS) == 0)) {
> +      continue;
> +    }
> +
> +    //
> +    // Compare the address and select the right one.
> +    //
> +    Status = Fvb->GetPhysicalAddress (Fvb, &FvbBaseAddress);
> +    if (EFI_ERROR (Status)) {
> +      continue;
> +    }
> +
> +    //
> +    // Assume one FVB has one type of BlockSize.
> +    //
> +    Status = Fvb->GetBlockSize (Fvb, 0, &BlockSize, &NumberOfBlocks);
> +    if (EFI_ERROR (Status)) {
> +      continue;
> +    }
> +
> +    if ((Address >= FvbBaseAddress) && (Address < (FvbBaseAddress + BlockSize *
> NumberOfBlocks))) {
> +      if (FvbHandle != NULL) {
> +        *FvbHandle = HandleBuffer[Index];
> +      }
> +
> +      if (FvbProtocol != NULL) {
> +        *FvbProtocol = Fvb;
> +      }
> +
> +      Status = EFI_SUCCESS;
> +      break;
> +    }
> +  }
> +
> +  FreePool (HandleBuffer);
> +
> +  if (Fvb == NULL) {
> +    Status = EFI_NOT_FOUND;
> +  }
> +
> +  return Status;
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableDxe.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableDxe.c
> new file mode 100644
> index 000000000000..4595bf8c9d02
> --- /dev/null
> +++ b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableDxe.c
> @@ -0,0 +1,670 @@
> +/** @file
> +  Implement all four UEFI Runtime Variable services for the nonvolatile
> +  and volatile storage space and install variable architecture protocol.
> +
> +Copyright (C) 2013, Red Hat, Inc.
> +Copyright (c) 2006 - 2022, Intel Corporation. All rights reserved.<BR>
> +(C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR>
> +Copyright (c) Microsoft Corporation.
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include "Variable.h"
> +
> +#include <Protocol/VariablePolicy.h>
> +#include <Library/VariablePolicyLib.h>
> +#include "VariableParsing.h"
> +
> +EFI_STATUS
> +EFIAPI
> +ProtocolIsVariablePolicyEnabled (
> +  OUT BOOLEAN  *State
> +  );
> +
> +EFI_HANDLE                      mHandle                      = NULL;
> +EFI_EVENT                       mVirtualAddressChangeEvent   = NULL;
> +VOID                            *mFtwRegistration            = NULL;
> +VOID                            ***mVarCheckAddressPointer   = NULL;
> +UINTN                           mVarCheckAddressPointerCount = 0;
> +EDKII_VARIABLE_LOCK_PROTOCOL    mVariableLock                =
> { VariableLockRequestToLock };
> +EDKII_VARIABLE_POLICY_PROTOCOL  mVariablePolicyProtocol      = {
> +  EDKII_VARIABLE_POLICY_PROTOCOL_REVISION,
> +  DisableVariablePolicy,
> +  ProtocolIsVariablePolicyEnabled,
> +  RegisterVariablePolicy,
> +  DumpVariablePolicy,
> +  LockVariablePolicy
> +};
> +EDKII_VAR_CHECK_PROTOCOL        mVarCheck = {
> +  VarCheckRegisterSetVariableCheckHandler,
> +  VarCheckVariablePropertySet,
> +  VarCheckVariablePropertyGet
> +};
> +
> +/**
> +  Some Secure Boot Policy Variable may update following other variable
> changes(SecureBoot follows PK change, etc).
> +  Record their initial State when variable write service is ready.
> +
> +**/
> +VOID
> +EFIAPI
> +RecordSecureBootPolicyVarData (
> +  VOID
> +  );
> +
> +/**
> +  Return TRUE if ExitBootServices () has been called.
> +
> +  @retval TRUE If ExitBootServices () has been called.
> +**/
> +BOOLEAN
> +AtRuntime (
> +  VOID
> +  )
> +{
> +  return EfiAtRuntime ();
> +}
> +
> +/**
> +  Initializes a basic mutual exclusion lock.
> +
> +  This function initializes a basic mutual exclusion lock to the released state
> +  and returns the lock.  Each lock provides mutual exclusion access at its task
> +  priority level.  Since there is no preemption or multiprocessor support in EFI,
> +  acquiring the lock only consists of raising to the locks TPL.
> +  If Lock is NULL, then ASSERT().
> +  If Priority is not a valid TPL value, then ASSERT().
> +
> +  @param  Lock       A pointer to the lock data structure to initialize.
> +  @param  Priority   EFI TPL is associated with the lock.
> +
> +  @return The lock.
> +
> +**/
> +EFI_LOCK *
> +InitializeLock (
> +  IN OUT EFI_LOCK  *Lock,
> +  IN     EFI_TPL   Priority
> +  )
> +{
> +  return EfiInitializeLock (Lock, Priority);
> +}
> +
> +/**
> +  Acquires lock only at boot time. Simply returns at runtime.
> +
> +  This is a temperary function that will be removed when
> +  EfiAcquireLock() in UefiLib can handle the call in UEFI
> +  Runtimer driver in RT phase.
> +  It calls EfiAcquireLock() at boot time, and simply returns
> +  at runtime.
> +
> +  @param  Lock         A pointer to the lock to acquire.
> +
> +**/
> +VOID
> +AcquireLockOnlyAtBootTime (
> +  IN EFI_LOCK  *Lock
> +  )
> +{
> +  if (!AtRuntime ()) {
> +    EfiAcquireLock (Lock);
> +  }
> +}
> +
> +/**
> +  Releases lock only at boot time. Simply returns at runtime.
> +
> +  This is a temperary function which will be removed when
> +  EfiReleaseLock() in UefiLib can handle the call in UEFI
> +  Runtimer driver in RT phase.
> +  It calls EfiReleaseLock() at boot time and simply returns
> +  at runtime.
> +
> +  @param  Lock         A pointer to the lock to release.
> +
> +**/
> +VOID
> +ReleaseLockOnlyAtBootTime (
> +  IN EFI_LOCK  *Lock
> +  )
> +{
> +  if (!AtRuntime ()) {
> +    EfiReleaseLock (Lock);
> +  }
> +}
> +
> +/**
> +  Retrieve the Fault Tolerent Write protocol interface.
> +
> +  @param[out] FtwProtocol       The interface of Ftw protocol
> +
> +  @retval EFI_SUCCESS           The FTW protocol instance was found and
> returned in FtwProtocol.
> +  @retval EFI_NOT_FOUND         The FTW protocol instance was not found.
> +  @retval EFI_INVALID_PARAMETER SarProtocol is NULL.
> +
> +**/
> +EFI_STATUS
> +GetFtwProtocol (
> +  OUT VOID  **FtwProtocol
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  //
> +  // Locate Fault Tolerent Write protocol
> +  //
> +  Status = gBS->LocateProtocol (
> +                  &gEfiFaultTolerantWriteProtocolGuid,
> +                  NULL,
> +                  FtwProtocol
> +                  );
> +  return Status;
> +}
> +
> +/**
> +  Retrieve the FVB protocol interface by HANDLE.
> +
> +  @param[in]  FvBlockHandle     The handle of FVB protocol that provides
> services for
> +                                reading, writing, and erasing the target block.
> +  @param[out] FvBlock           The interface of FVB protocol
> +
> +  @retval EFI_SUCCESS           The interface information for the specified
> protocol was returned.
> +  @retval EFI_UNSUPPORTED       The device does not support the FVB protocol.
> +  @retval EFI_INVALID_PARAMETER FvBlockHandle is not a valid EFI_HANDLE
> or FvBlock is NULL.
> +
> +**/
> +EFI_STATUS
> +GetFvbByHandle (
> +  IN  EFI_HANDLE                          FvBlockHandle,
> +  OUT EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  **FvBlock
> +  )
> +{
> +  //
> +  // To get the FVB protocol interface on the handle
> +  //
> +  return gBS->HandleProtocol (
> +                FvBlockHandle,
> +                &gEfiFirmwareVolumeBlockProtocolGuid,
> +                (VOID **)FvBlock
> +                );
> +}
> +
> +/**
> +  Function returns an array of handles that support the FVB protocol
> +  in a buffer allocated from pool.
> +
> +  @param[out]  NumberHandles    The number of handles returned in Buffer.
> +  @param[out]  Buffer           A pointer to the buffer to return the requested
> +                                array of  handles that support FVB protocol.
> +
> +  @retval EFI_SUCCESS           The array of handles was returned in Buffer, and
> the number of
> +                                handles in Buffer was returned in NumberHandles.
> +  @retval EFI_NOT_FOUND         No FVB handle was found.
> +  @retval EFI_OUT_OF_RESOURCES  There is not enough pool memory to store
> the matching results.
> +  @retval EFI_INVALID_PARAMETER NumberHandles is NULL or Buffer is NULL.
> +
> +**/
> +EFI_STATUS
> +GetFvbCountAndBuffer (
> +  OUT UINTN       *NumberHandles,
> +  OUT EFI_HANDLE  **Buffer
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  //
> +  // Locate all handles of Fvb protocol
> +  //
> +  Status = gBS->LocateHandleBuffer (
> +                  ByProtocol,
> +                  &gEfiFirmwareVolumeBlockProtocolGuid,
> +                  NULL,
> +                  NumberHandles,
> +                  Buffer
> +                  );
> +  return Status;
> +}
> +
> +/**
> +  Notification function of EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE.
> +
> +  This is a notification function registered on
> EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE event.
> +  It convers pointer to new virtual address.
> +
> +  @param  Event        Event whose notification function is being invoked.
> +  @param  Context      Pointer to the notification function's context.
> +
> +**/
> +VOID
> +EFIAPI
> +VariableClassAddressChangeEvent (
> +  IN EFI_EVENT  Event,
> +  IN VOID       *Context
> +  )
> +{
> +  UINTN  Index;
> +
> +  if (mVariableModuleGlobal->FvbInstance != NULL) {
> +    EfiConvertPointer (0x0, (VOID **)&mVariableModuleGlobal->FvbInstance-
> >GetBlockSize);
> +    EfiConvertPointer (0x0, (VOID **)&mVariableModuleGlobal->FvbInstance-
> >GetPhysicalAddress);
> +    EfiConvertPointer (0x0, (VOID **)&mVariableModuleGlobal->FvbInstance-
> >GetAttributes);
> +    EfiConvertPointer (0x0, (VOID **)&mVariableModuleGlobal->FvbInstance-
> >SetAttributes);
> +    EfiConvertPointer (0x0, (VOID **)&mVariableModuleGlobal->FvbInstance-
> >Read);
> +    EfiConvertPointer (0x0, (VOID **)&mVariableModuleGlobal->FvbInstance-
> >Write);
> +    EfiConvertPointer (0x0, (VOID **)&mVariableModuleGlobal->FvbInstance-
> >EraseBlocks);
> +    EfiConvertPointer (0x0, (VOID **)&mVariableModuleGlobal->FvbInstance);
> +  }
> +
> +  EfiConvertPointer (0x0, (VOID **)&mVariableModuleGlobal-
> >PlatformLangCodes);
> +  EfiConvertPointer (0x0, (VOID **)&mVariableModuleGlobal->LangCodes);
> +  EfiConvertPointer (0x0, (VOID **)&mVariableModuleGlobal->PlatformLang);
> +  EfiConvertPointer (0x0, (VOID **)&mVariableModuleGlobal-
> >VariableGlobal.NonVolatileVariableBase);
> +  EfiConvertPointer (0x0, (VOID **)&mVariableModuleGlobal-
> >VariableGlobal.VolatileVariableBase);
> +  EfiConvertPointer (0x0, (VOID **)&mVariableModuleGlobal-
> >VariableGlobal.HobVariableBase);
> +  EfiConvertPointer (0x0, (VOID **)&mVariableModuleGlobal);
> +  EfiConvertPointer (0x0, (VOID **)&mNvVariableCache);
> +  EfiConvertPointer (0x0, (VOID **)&mNvFvHeaderCache);
> +
> +  if (mAuthContextOut.AddressPointer != NULL) {
> +    for (Index = 0; Index < mAuthContextOut.AddressPointerCount; Index++) {
> +      EfiConvertPointer (0x0, (VOID **)mAuthContextOut.AddressPointer[Index]);
> +    }
> +  }
> +
> +  if (mVarCheckAddressPointer != NULL) {
> +    for (Index = 0; Index < mVarCheckAddressPointerCount; Index++) {
> +      EfiConvertPointer (0x0, (VOID **)mVarCheckAddressPointer[Index]);
> +    }
> +  }
> +}
> +
> +/**
> +  Notification function of EVT_GROUP_READY_TO_BOOT event group.
> +
> +  This is a notification function registered on EVT_GROUP_READY_TO_BOOT
> event group.
> +  When the Boot Manager is about to load and execute a boot option, it
> reclaims variable
> +  storage if free size is below the threshold.
> +
> +  @param  Event        Event whose notification function is being invoked.
> +  @param  Context      Pointer to the notification function's context.
> +
> +**/
> +VOID
> +EFIAPI
> +OnReadyToBoot (
> +  EFI_EVENT  Event,
> +  VOID       *Context
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  if (!mEndOfDxe) {
> +    MorLockInitAtEndOfDxe ();
> +
> +    Status = LockVariablePolicy ();
> +    ASSERT_EFI_ERROR (Status);
> +    //
> +    // Set the End Of DXE bit in case the EFI_END_OF_DXE_EVENT_GROUP_GUID
> event is not signaled.
> +    //
> +    mEndOfDxe               = TRUE;
> +    mVarCheckAddressPointer = VarCheckLibInitializeAtEndOfDxe
> (&mVarCheckAddressPointerCount);
> +    //
> +    // The initialization for variable quota.
> +    //
> +    InitializeVariableQuota ();
> +  }
> +
> +  ReclaimForOS ();
> +  if (FeaturePcdGet (PcdVariableCollectStatistics)) {
> +    if (mVariableModuleGlobal->VariableGlobal.AuthFormat) {
> +      gBS->InstallConfigurationTable (&gEfiAuthenticatedVariableGuid,
> gVariableInfo);
> +    } else {
> +      gBS->InstallConfigurationTable (&gEfiVariableGuid, gVariableInfo);
> +    }
> +  }
> +
> +  gBS->CloseEvent (Event);
> +}
> +
> +/**
> +  Notification function of EFI_END_OF_DXE_EVENT_GROUP_GUID event group.
> +
> +  This is a notification function registered on
> EFI_END_OF_DXE_EVENT_GROUP_GUID event group.
> +
> +  @param  Event        Event whose notification function is being invoked.
> +  @param  Context      Pointer to the notification function's context.
> +
> +**/
> +VOID
> +EFIAPI
> +OnEndOfDxe (
> +  EFI_EVENT  Event,
> +  VOID       *Context
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  DEBUG ((DEBUG_INFO, "[Variable]END_OF_DXE is signaled\n"));
> +  MorLockInitAtEndOfDxe ();
> +  Status = LockVariablePolicy ();
> +  ASSERT_EFI_ERROR (Status);
> +  mEndOfDxe               = TRUE;
> +  mVarCheckAddressPointer = VarCheckLibInitializeAtEndOfDxe
> (&mVarCheckAddressPointerCount);
> +  //
> +  // The initialization for variable quota.
> +  //
> +  InitializeVariableQuota ();
> +  if (PcdGetBool (PcdReclaimVariableSpaceAtEndOfDxe)) {
> +    ReclaimForOS ();
> +  }
> +
> +  gBS->CloseEvent (Event);
> +}
> +
> +/**
> +  Initializes variable write service for DXE.
> +
> +**/
> +VOID
> +VariableWriteServiceInitializeDxe (
> +  VOID
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  Status = VariableWriteServiceInitialize ();
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "Variable write service initialization failed. Status
> = %r\n", Status));
> +  }
> +
> +  //
> +  // Some Secure Boot Policy Var (SecureBoot, etc) updates following other
> +  // Secure Boot Policy Variable change. Record their initial value.
> +  //
> +  RecordSecureBootPolicyVarData ();
> +
> +  //
> +  // Install the Variable Write Architectural protocol.
> +  //
> +  Status = gBS->InstallProtocolInterface (
> +                  &mHandle,
> +                  &gEfiVariableWriteArchProtocolGuid,
> +                  EFI_NATIVE_INTERFACE,
> +                  NULL
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +}
> +
> +/**
> +  Fault Tolerant Write protocol notification event handler.
> +
> +  Non-Volatile variable write may needs FTW protocol to reclaim when
> +  writting variable.
> +
> +  @param[in] Event    Event whose notification function is being invoked.
> +  @param[in] Context  Pointer to the notification function's context.
> +
> +**/
> +VOID
> +EFIAPI
> +FtwNotificationEvent (
> +  IN  EFI_EVENT  Event,
> +  IN  VOID       *Context
> +  )
> +{
> +  EFI_STATUS                          Status;
> +  EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  *FvbProtocol;
> +  EFI_FAULT_TOLERANT_WRITE_PROTOCOL   *FtwProtocol;
> +  EFI_PHYSICAL_ADDRESS                NvStorageVariableBase;
> +  EFI_GCD_MEMORY_SPACE_DESCRIPTOR     GcdDescriptor;
> +  EFI_PHYSICAL_ADDRESS                BaseAddress;
> +  UINT64                              Length;
> +  EFI_PHYSICAL_ADDRESS                VariableStoreBase;
> +  UINT64                              VariableStoreLength;
> +  UINTN                               FtwMaxBlockSize;
> +  UINT32                              NvStorageVariableSize;
> +  UINT64                              NvStorageVariableSize64;
> +
> +  //
> +  // Ensure FTW protocol is installed.
> +  //
> +  Status = GetFtwProtocol ((VOID **)&FtwProtocol);
> +  if (EFI_ERROR (Status)) {
> +    return;
> +  }
> +
> +  Status = GetVariableFlashNvStorageInfo (&NvStorageVariableBase,
> &NvStorageVariableSize64);
> +  ASSERT_EFI_ERROR (Status);
> +
> +  Status = SafeUint64ToUint32 (NvStorageVariableSize64,
> &NvStorageVariableSize);
> +  // This driver currently assumes the size will be UINT32 so assert the value is
> safe for now.
> +  ASSERT_EFI_ERROR (Status);
> +
> +  VariableStoreBase = NvStorageVariableBase + mNvFvHeaderCache-
> >HeaderLength;
> +
> +  Status = FtwProtocol->GetMaxBlockSize (FtwProtocol, &FtwMaxBlockSize);
> +  if (!EFI_ERROR (Status)) {
> +    ASSERT (NvStorageVariableSize <= FtwMaxBlockSize);
> +  }
> +
> +  //
> +  // Let NonVolatileVariableBase point to flash variable store base directly after
> FTW ready.
> +  //
> +  mVariableModuleGlobal->VariableGlobal.NonVolatileVariableBase =
> VariableStoreBase;
> +
> +  //
> +  // Find the proper FVB protocol for variable.
> +  //
> +  Status = GetFvbInfoByAddress (NvStorageVariableBase, NULL, &FvbProtocol);
> +  if (EFI_ERROR (Status)) {
> +    return;
> +  }
> +
> +  mVariableModuleGlobal->FvbInstance = FvbProtocol;
> +
> +  //
> +  // Mark the variable storage region of the FLASH as RUNTIME.
> +  //
> +  VariableStoreLength = mNvVariableCache->Size;
> +  BaseAddress         = VariableStoreBase & (~EFI_PAGE_MASK);
> +  Length              = VariableStoreLength + (VariableStoreBase - BaseAddress);
> +  Length              = (Length + EFI_PAGE_SIZE - 1) & (~EFI_PAGE_MASK);
> +
> +  Status = gDS->GetMemorySpaceDescriptor (BaseAddress, &GcdDescriptor);
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_WARN, "Variable driver failed to get flash memory
> attribute.\n"));
> +  } else {
> +    if ((GcdDescriptor.Attributes & EFI_MEMORY_RUNTIME) == 0) {
> +      Status = gDS->SetMemorySpaceAttributes (
> +                      BaseAddress,
> +                      Length,
> +                      GcdDescriptor.Attributes | EFI_MEMORY_RUNTIME
> +                      );
> +      if (EFI_ERROR (Status)) {
> +        DEBUG ((DEBUG_WARN, "Variable driver failed to add
> EFI_MEMORY_RUNTIME attribute to Flash.\n"));
> +      }
> +    }
> +  }
> +
> +  //
> +  // Initializes variable write service after FTW was ready.
> +  //
> +  VariableWriteServiceInitializeDxe ();
> +
> +  //
> +  // Close the notify event to avoid install gEfiVariableWriteArchProtocolGuid
> again.
> +  //
> +  gBS->CloseEvent (Event);
> +}
> +
> +/**
> +  This API function returns whether or not the policy engine is
> +  currently being enforced.
> +
> +  @param[out]   State       Pointer to a return value for whether the policy
> enforcement
> +                            is currently enabled.
> +
> +  @retval     EFI_SUCCESS
> +  @retval     Others        An error has prevented this command from completing.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +ProtocolIsVariablePolicyEnabled (
> +  OUT BOOLEAN  *State
> +  )
> +{
> +  *State = IsVariablePolicyEnabled ();
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Variable Driver main entry point. The Variable driver places the 4 EFI
> +  runtime services in the EFI System Table and installs arch protocols
> +  for variable read and write services being available. It also registers
> +  a notification function for an EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE
> event.
> +
> +  @param[in] ImageHandle    The firmware allocated handle for the EFI image.
> +  @param[in] SystemTable    A pointer to the EFI System Table.
> +
> +  @retval EFI_SUCCESS       Variable service successfully initialized.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableServiceInitialize (
> +  IN EFI_HANDLE        ImageHandle,
> +  IN EFI_SYSTEM_TABLE  *SystemTable
> +  )
> +{
> +  EFI_STATUS  Status;
> +  EFI_EVENT   ReadyToBootEvent;
> +  EFI_EVENT   EndOfDxeEvent;
> +
> +  PROTECTED_VARIABLE_CONTEXT_IN  ContextIn;
> +
> +  //
> +  // Initialze protected variable service, if enabled.
> +  //
> +  ContextIn.StructSize    = sizeof (ContextIn);
> +  ContextIn.StructVersion =
> PROTECTED_VARIABLE_CONTEXT_IN_STRUCT_VERSION;
> +
> +  ContextIn.FindVariableSmm     = NULL;
> +  ContextIn.GetVariableInfo     = GetVariableInfo;
> +  ContextIn.GetNextVariableInfo = GetNextVariableInfo;
> +  ContextIn.UpdateVariableStore = VariableExLibUpdateNvVariable;
> +  ContextIn.UpdateVariable      = VariableExLibUpdateVariable;
> +
> +  ContextIn.MaxVariableSize     = (UINT32)GetMaxVariableSize ();
> +  ContextIn.VariableServiceUser = FromSmmModule;
> +
> +  Status = ProtectedVariableLibInitialize (&ContextIn);
> +  if (EFI_ERROR (Status) && (Status != EFI_UNSUPPORTED)) {
> +    ASSERT_EFI_ERROR (Status);
> +    return Status;
> +  }
> +
> +  Status = VariableCommonInitialize ();
> +  ASSERT_EFI_ERROR (Status);
> +
> +  Status = gBS->InstallMultipleProtocolInterfaces (
> +                  &mHandle,
> +                  &gEdkiiVariableLockProtocolGuid,
> +                  &mVariableLock,
> +                  NULL
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  Status = gBS->InstallMultipleProtocolInterfaces (
> +                  &mHandle,
> +                  &gEdkiiVarCheckProtocolGuid,
> +                  &mVarCheck,
> +                  NULL
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  SystemTable->RuntimeServices->GetVariable         =
> VariableServiceGetVariable;
> +  SystemTable->RuntimeServices->GetNextVariableName =
> VariableServiceGetNextVariableName;
> +  SystemTable->RuntimeServices->SetVariable         = VariableServiceSetVariable;
> +  SystemTable->RuntimeServices->QueryVariableInfo   =
> VariableServiceQueryVariableInfo;
> +
> +  //
> +  // Now install the Variable Runtime Architectural protocol on a new handle.
> +  //
> +  Status = gBS->InstallProtocolInterface (
> +                  &mHandle,
> +                  &gEfiVariableArchProtocolGuid,
> +                  EFI_NATIVE_INTERFACE,
> +                  NULL
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  if (!PcdGetBool (PcdEmuVariableNvModeEnable)) {
> +    //
> +    // Register FtwNotificationEvent () notify function.
> +    //
> +    EfiCreateProtocolNotifyEvent (
> +      &gEfiFaultTolerantWriteProtocolGuid,
> +      TPL_CALLBACK,
> +      FtwNotificationEvent,
> +      (VOID *)SystemTable,
> +      &mFtwRegistration
> +      );
> +  } else {
> +    //
> +    // Emulated non-volatile variable mode does not depend on FVB and FTW.
> +    //
> +    VariableWriteServiceInitializeDxe ();
> +  }
> +
> +  Status = gBS->CreateEventEx (
> +                  EVT_NOTIFY_SIGNAL,
> +                  TPL_NOTIFY,
> +                  VariableClassAddressChangeEvent,
> +                  NULL,
> +                  &gEfiEventVirtualAddressChangeGuid,
> +                  &mVirtualAddressChangeEvent
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  //
> +  // Register the event handling function to reclaim variable for OS usage.
> +  //
> +  Status = EfiCreateEventReadyToBootEx (
> +             TPL_NOTIFY,
> +             OnReadyToBoot,
> +             NULL,
> +             &ReadyToBootEvent
> +             );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  //
> +  // Register the event handling function to set the End Of DXE flag.
> +  //
> +  Status = gBS->CreateEventEx (
> +                  EVT_NOTIFY_SIGNAL,
> +                  TPL_CALLBACK,
> +                  OnEndOfDxe,
> +                  NULL,
> +                  &gEfiEndOfDxeEventGroupGuid,
> +                  &EndOfDxeEvent
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  // Register and initialize the VariablePolicy engine.
> +  Status = InitVariablePolicyLib (VariableServiceGetVariable);
> +  ASSERT_EFI_ERROR (Status);
> +  Status = VarCheckRegisterSetVariableCheckHandler (ValidateSetVariable);
> +  ASSERT_EFI_ERROR (Status);
> +  Status = gBS->InstallMultipleProtocolInterfaces (
> +                  &mHandle,
> +                  &gEdkiiVariablePolicyProtocolGuid,
> +                  &mVariablePolicyProtocol,
> +                  NULL
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  return EFI_SUCCESS;
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableExLib.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableExLib.c
> new file mode 100644
> index 000000000000..5904bcbff78a
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableExLib.c
> @@ -0,0 +1,417 @@
> +/** @file
> +  Provides variable driver extended services.
> +
> +Copyright (c) 2015 - 2022, Intel Corporation. All rights reserved.<BR>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include "Variable.h"
> +#include "VariableParsing.h"
> +#include "VariableRuntimeCache.h"
> +
> +/**
> +  Finds variable in storage blocks of volatile and non-volatile storage areas.
> +
> +  This code finds variable in storage blocks of volatile and non-volatile storage
> areas.
> +  If VariableName is an empty string, then we just return the first
> +  qualified variable without comparing VariableName and VendorGuid.
> +
> +  @param[in]  VariableName          Name of the variable to be found.
> +  @param[in]  VendorGuid            Variable vendor GUID to be found.
> +  @param[out] AuthVariableInfo      Pointer to AUTH_VARIABLE_INFO structure
> for
> +                                    output of the variable found.
> +
> +  @retval EFI_INVALID_PARAMETER     If VariableName is not an empty string,
> +                                    while VendorGuid is NULL.
> +  @retval EFI_SUCCESS               Variable successfully found.
> +  @retval EFI_NOT_FOUND             Variable not found
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableExLibFindVariable (
> +  IN  CHAR16              *VariableName,
> +  IN  EFI_GUID            *VendorGuid,
> +  OUT AUTH_VARIABLE_INFO  *AuthVariableInfo
> +  )
> +{
> +  EFI_STATUS                     Status;
> +  VARIABLE_POINTER_TRACK         Variable;
> +  AUTHENTICATED_VARIABLE_HEADER  *AuthVariable;
> +  PROTECTED_VARIABLE_INFO        VarInfo;
> +
> +  Status = FindVariable (
> +             VariableName,
> +             VendorGuid,
> +             &Variable,
> +             &mVariableModuleGlobal->VariableGlobal,
> +             FALSE
> +             );
> +  if (EFI_ERROR (Status)) {
> +    AuthVariableInfo->Data           = NULL;
> +    AuthVariableInfo->DataSize       = 0;
> +    AuthVariableInfo->Attributes     = 0;
> +    AuthVariableInfo->PubKeyIndex    = 0;
> +    AuthVariableInfo->MonotonicCount = 0;
> +    AuthVariableInfo->TimeStamp      = NULL;
> +    return Status;
> +  }
> +
> +  AuthVariableInfo->NameSize     = NameSizeOfVariable (Variable.CurrPtr,
> mVariableModuleGlobal->VariableGlobal.AuthFormat);
> +  AuthVariableInfo->VariableName = GetVariableNamePtr (Variable.CurrPtr,
> mVariableModuleGlobal->VariableGlobal.AuthFormat);
> +  AuthVariableInfo->VendorGuid   = GetVendorGuidPtr (Variable.CurrPtr,
> mVariableModuleGlobal->VariableGlobal.AuthFormat);
> +  AuthVariableInfo->DataSize     = DataSizeOfVariable (Variable.CurrPtr,
> mVariableModuleGlobal->VariableGlobal.AuthFormat);
> +  AuthVariableInfo->Data         = GetVariableDataPtr (Variable.CurrPtr,
> mVariableModuleGlobal->VariableGlobal.AuthFormat);
> +  AuthVariableInfo->Attributes   = Variable.CurrPtr->Attributes;
> +  if (mVariableModuleGlobal->VariableGlobal.AuthFormat) {
> +    AuthVariable                     = (AUTHENTICATED_VARIABLE_HEADER
> *)Variable.CurrPtr;
> +    AuthVariableInfo->PubKeyIndex    = AuthVariable->PubKeyIndex;
> +    AuthVariableInfo->MonotonicCount = ReadUnaligned64 (&(AuthVariable-
> >MonotonicCount));
> +    AuthVariableInfo->TimeStamp      = &AuthVariable->TimeStamp;
> +  }
> +
> +  CopyMem (&VarInfo.Header, AuthVariableInfo, sizeof (VarInfo.Header));
> +
> +  VarInfo.Buffer        = Variable.CurrPtr;
> +  VarInfo.PlainData     = NULL;
> +  VarInfo.PlainDataSize = 0;
> +  VarInfo.Flags.Auth    = mVariableModuleGlobal->VariableGlobal.AuthFormat;
> +
> +  //
> +  // In case the variable is encrypted.
> +  //
> +  Status = ProtectedVariableLibGetByInfo (&VarInfo);
> +  if (!EFI_ERROR (Status)) {
> +    if (VarInfo.PlainData != NULL) {
> +      AuthVariableInfo->Data     = VarInfo.PlainData;
> +      AuthVariableInfo->DataSize = VarInfo.PlainDataSize;
> +    }
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Finds next variable in storage blocks of volatile and non-volatile storage areas.
> +
> +  This code finds next variable in storage blocks of volatile and non-volatile
> storage areas.
> +  If VariableName is an empty string, then we just return the first
> +  qualified variable without comparing VariableName and VendorGuid.
> +
> +  @param[in]  VariableName          Name of the variable to be found.
> +  @param[in]  VendorGuid            Variable vendor GUID to be found.
> +  @param[out] AuthVariableInfo      Pointer to AUTH_VARIABLE_INFO structure
> for
> +                                    output of the next variable.
> +
> +  @retval EFI_INVALID_PARAMETER     If VariableName is not an empty string,
> +                                    while VendorGuid is NULL.
> +  @retval EFI_SUCCESS               Variable successfully found.
> +  @retval EFI_NOT_FOUND             Variable not found
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableExLibFindNextVariable (
> +  IN  CHAR16              *VariableName,
> +  IN  EFI_GUID            *VendorGuid,
> +  OUT AUTH_VARIABLE_INFO  *AuthVariableInfo
> +  )
> +{
> +  EFI_STATUS                     Status;
> +  VARIABLE_HEADER                *VariablePtr;
> +  AUTHENTICATED_VARIABLE_HEADER  *AuthVariablePtr;
> +  VARIABLE_STORE_HEADER
> *VariableStoreHeader[VariableStoreTypeMax];
> +  PROTECTED_VARIABLE_INFO        VarInfo;
> +
> +  VariableStoreHeader[VariableStoreTypeVolatile] =
> (VARIABLE_STORE_HEADER *)(UINTN)mVariableModuleGlobal-
> >VariableGlobal.VolatileVariableBase;
> +  VariableStoreHeader[VariableStoreTypeHob]      = (VARIABLE_STORE_HEADER
> *)(UINTN)mVariableModuleGlobal->VariableGlobal.HobVariableBase;
> +  VariableStoreHeader[VariableStoreTypeNv]       = mNvVariableCache;
> +
> +  Status = VariableServiceGetNextVariableInternal (
> +             VariableName,
> +             VendorGuid,
> +             VariableStoreHeader,
> +             &VariablePtr,
> +             mVariableModuleGlobal->VariableGlobal.AuthFormat
> +             );
> +  if (EFI_ERROR (Status)) {
> +    AuthVariableInfo->VariableName   = NULL;
> +    AuthVariableInfo->VendorGuid     = NULL;
> +    AuthVariableInfo->Data           = NULL;
> +    AuthVariableInfo->DataSize       = 0;
> +    AuthVariableInfo->Attributes     = 0;
> +    AuthVariableInfo->PubKeyIndex    = 0;
> +    AuthVariableInfo->MonotonicCount = 0;
> +    AuthVariableInfo->TimeStamp      = NULL;
> +    return Status;
> +  }
> +
> +  AuthVariableInfo->NameSize     = NameSizeOfVariable (VariablePtr,
> mVariableModuleGlobal->VariableGlobal.AuthFormat);
> +  AuthVariableInfo->VariableName = GetVariableNamePtr (VariablePtr,
> mVariableModuleGlobal->VariableGlobal.AuthFormat);
> +  AuthVariableInfo->VendorGuid   = GetVendorGuidPtr (VariablePtr,
> mVariableModuleGlobal->VariableGlobal.AuthFormat);
> +  AuthVariableInfo->DataSize     = DataSizeOfVariable (VariablePtr,
> mVariableModuleGlobal->VariableGlobal.AuthFormat);
> +  AuthVariableInfo->Data         = GetVariableDataPtr (VariablePtr,
> mVariableModuleGlobal->VariableGlobal.AuthFormat);
> +  AuthVariableInfo->Attributes   = VariablePtr->Attributes;
> +  if (mVariableModuleGlobal->VariableGlobal.AuthFormat) {
> +    AuthVariablePtr                  = (AUTHENTICATED_VARIABLE_HEADER
> *)VariablePtr;
> +    AuthVariableInfo->PubKeyIndex    = AuthVariablePtr->PubKeyIndex;
> +    AuthVariableInfo->MonotonicCount = ReadUnaligned64 (&(AuthVariablePtr-
> >MonotonicCount));
> +    AuthVariableInfo->TimeStamp      = &AuthVariablePtr->TimeStamp;
> +  }
> +
> +  CopyMem (&VarInfo.Header, AuthVariableInfo, sizeof (VarInfo.Header));
> +
> +  VarInfo.Buffer        = VariablePtr;
> +  VarInfo.PlainData     = NULL;
> +  VarInfo.PlainDataSize = 0;
> +
> +  Status = ProtectedVariableLibGetByInfo (&VarInfo);
> +  if (!EFI_ERROR (Status)) {
> +    if (VarInfo.PlainData != NULL) {
> +      AuthVariableInfo->Data     = VarInfo.PlainData;
> +      AuthVariableInfo->DataSize = VarInfo.PlainDataSize;
> +    }
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Update the variable region with Variable information.
> +
> +  @param[in] AuthVariableInfo       Pointer AUTH_VARIABLE_INFO structure for
> +                                    input of the variable.
> +
> +  @retval EFI_SUCCESS               The update operation is success.
> +  @retval EFI_INVALID_PARAMETER     Invalid parameter.
> +  @retval EFI_WRITE_PROTECTED       Variable is write-protected.
> +  @retval EFI_OUT_OF_RESOURCES      There is not enough resource.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableExLibUpdateVariable (
> +  IN AUTH_VARIABLE_INFO  *AuthVariableInfo
> +  )
> +{
> +  VARIABLE_POINTER_TRACK  Variable;
> +
> +  FindVariable (AuthVariableInfo->VariableName, AuthVariableInfo-
> >VendorGuid, &Variable, &mVariableModuleGlobal->VariableGlobal, FALSE);
> +  return UpdateVariable (
> +           AuthVariableInfo->VariableName,
> +           AuthVariableInfo->VendorGuid,
> +           AuthVariableInfo->Data,
> +           AuthVariableInfo->DataSize,
> +           AuthVariableInfo->Attributes,
> +           AuthVariableInfo->PubKeyIndex,
> +           AuthVariableInfo->MonotonicCount,
> +           &Variable,
> +           AuthVariableInfo->TimeStamp
> +           );
> +}
> +
> +/**
> +  Get scratch buffer.
> +
> +  @param[in, out] ScratchBufferSize Scratch buffer size. If input size is greater
> than
> +                                    the maximum supported buffer size, this value contains
> +                                    the maximum supported buffer size as output.
> +  @param[out]     ScratchBuffer     Pointer to scratch buffer address.
> +
> +  @retval EFI_SUCCESS       Get scratch buffer successfully.
> +  @retval EFI_UNSUPPORTED   If input size is greater than the maximum
> supported buffer size.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableExLibGetScratchBuffer (
> +  IN OUT UINTN  *ScratchBufferSize,
> +  OUT    VOID   **ScratchBuffer
> +  )
> +{
> +  UINTN  MaxBufferSize;
> +
> +  MaxBufferSize = mVariableModuleGlobal->ScratchBufferSize;
> +  if (*ScratchBufferSize > MaxBufferSize) {
> +    *ScratchBufferSize = MaxBufferSize;
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  *ScratchBuffer = GetEndPointer ((VARIABLE_STORE_HEADER
> *)((UINTN)mVariableModuleGlobal->VariableGlobal.VolatileVariableBase));
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  This function is to check if the remaining variable space is enough to set
> +  all Variables from argument list successfully. The purpose of the check
> +  is to keep the consistency of the Variables to be in variable storage.
> +
> +  Note: Variables are assumed to be in same storage.
> +  The set sequence of Variables will be same with the sequence of VariableEntry
> from argument list,
> +  so follow the argument sequence to check the Variables.
> +
> +  @param[in] Attributes         Variable attributes for Variable entries.
> +  @param ...                    The variable argument list with type
> VARIABLE_ENTRY_CONSISTENCY *.
> +                                A NULL terminates the list. The VariableSize of
> +                                VARIABLE_ENTRY_CONSISTENCY is the variable data size as
> input.
> +                                It will be changed to variable total size as output.
> +
> +  @retval TRUE                  Have enough variable space to set the Variables
> successfully.
> +  @retval FALSE                 No enough variable space to set the Variables
> successfully.
> +
> +**/
> +BOOLEAN
> +EFIAPI
> +VariableExLibCheckRemainingSpaceForConsistency (
> +  IN UINT32  Attributes,
> +  ...
> +  )
> +{
> +  VA_LIST  Marker;
> +  BOOLEAN  Return;
> +
> +  VA_START (Marker, Attributes);
> +
> +  Return = CheckRemainingSpaceForConsistencyInternal (Attributes, Marker);
> +
> +  VA_END (Marker);
> +
> +  return Return;
> +}
> +
> +/**
> +  Return TRUE if at OS runtime.
> +
> +  @retval TRUE If at OS runtime.
> +  @retval FALSE If at boot time.
> +
> +**/
> +BOOLEAN
> +EFIAPI
> +VariableExLibAtRuntime (
> +  VOID
> +  )
> +{
> +  return AtRuntime ();
> +}
> +
> +/**
> +  Update partial data of a variable on NV storage and/or cached copy.
> +
> +  @param[in]  VariableInfo  Pointer to a variable with detailed information.
> +  @param[in]  Offset        Offset to write from.
> +  @param[in]  Size          Size of data Buffer to update.
> +  @param[in]  Buffer        Pointer to data buffer to update.
> +
> +  @retval EFI_SUCCESS             The variable data was updated successfully.
> +  @retval EFI_UNSUPPORTED         If this function is called directly in runtime.
> +  @retval EFI_INVALID_PARAMETER   If VariableInfo, Buffer or Size are not
> valid.
> +  @retval Others                  Failed to update NV storage or variable cache.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableExLibUpdateNvVariable (
> +  IN  PROTECTED_VARIABLE_INFO  *VariableInfo,
> +  IN  UINTN                    Offset,
> +  IN  UINT32                   Size,
> +  IN  UINT8                    *Buffer
> +  )
> +{
> +  EFI_STATUS              Status;
> +  VARIABLE_GLOBAL         *Global;
> +  VARIABLE_RUNTIME_CACHE  *CacheInstance;
> +  VARIABLE_HEADER         *VariableCache;
> +
> +  if ((mVariableModuleGlobal == NULL) || (mNvVariableCache == NULL)) {
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  //
> +  // Flush the cache to store.
> +  //
> +  if (Size == (UINT32)-1) {
> +    Status = FtwVariableSpace (
> +               mVariableModuleGlobal->VariableGlobal.NonVolatileVariableBase,
> +               mNvVariableCache
> +               );
> +    if (  !EFI_ERROR (Status)
> +       && (mVariableModuleGlobal->VariableGlobal.HobVariableBase != 0))
> +    {
> +      FlushHobVariableToFlash (NULL, NULL);
> +      if (mVariableModuleGlobal->VariableGlobal.HobVariableBase != 0) {
> +        FreePool ((VOID *)(UINTN)mVariableModuleGlobal-
> >VariableGlobal.HobVariableBase);
> +        mVariableModuleGlobal->VariableGlobal.HobVariableBase = 0;
> +      }
> +    }
> +
> +    return Status;
> +  }
> +
> +  if (  (VariableInfo == NULL)
> +     || (VariableInfo->StoreIndex == VAR_INDEX_INVALID)
> +     || (Buffer == NULL)
> +     || (Size == 0))
> +  {
> +    ASSERT (VariableInfo != NULL);
> +    ASSERT (VariableInfo->StoreIndex != VAR_INDEX_INVALID);
> +    ASSERT (Buffer != NULL);
> +    ASSERT (Size != 0);
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  Global = &mVariableModuleGlobal->VariableGlobal;
> +
> +  VariableCache = (VARIABLE_HEADER *)((UINTN)mNvVariableCache +
> (UINTN)VariableInfo->StoreIndex);
> +
> +  ASSERT (
> +    StrCmp (
> +      VariableInfo->Header.VariableName,
> +      GetVariableNamePtr (VariableCache, Global->AuthFormat)
> +      ) == 0
> +    );
> +  ASSERT (
> +    CompareGuid (
> +      VariableInfo->Header.VendorGuid,
> +      GetVendorGuidPtr (VariableCache, Global->AuthFormat)
> +      )
> +    );
> +
> +  //
> +  // Forcibly update part data of flash copy of the variable ...
> +  //
> +  Status =  UpdateVariableStore (
> +              Global,
> +              FALSE,
> +              FALSE,
> +              mVariableModuleGlobal->FvbInstance,
> +              (UINTN)(Global->NonVolatileVariableBase + VariableInfo->StoreIndex +
> Offset),
> +              Size,
> +              Buffer
> +              );
> +  if (EFI_ERROR (Status)) {
> +    ASSERT_EFI_ERROR (Status);
> +    return Status;
> +  }
> +
> +  //
> +  // ... as well as the local cached copy.
> +  //
> +  CopyMem ((VOID *)((UINTN)VariableCache + Offset), Buffer, Size);
> +
> +  //
> +  // Sync remote cached copy.
> +  //
> +  CacheInstance = &Global-
> >VariableRuntimeCacheContext.VariableRuntimeNvCache;
> +  if (CacheInstance->Store != NULL) {
> +    Status =  SynchronizeRuntimeVariableCache (
> +                CacheInstance,
> +                (UINTN)VariableInfo->StoreIndex + Offset,
> +                Size
> +                );
> +    ASSERT_EFI_ERROR (Status);
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableLockRequ
> estToLock.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableLockRequ
> estToLock.c
> new file mode 100644
> index 000000000000..d849ee9ce292
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableLockRequ
> estToLock.c
> @@ -0,0 +1,96 @@
> +/** @file
> +  Temporary location of the RequestToLock shim code while projects
> +  are moved to VariablePolicy. Should be removed when deprecated.
> +
> +  Copyright (c) Microsoft Corporation.
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <Uefi.h>
> +#include <Library/DebugLib.h>
> +#include <Library/MemoryAllocationLib.h>
> +#include <Library/VariablePolicyLib.h>
> +#include <Library/VariablePolicyHelperLib.h>
> +#include <Protocol/VariableLock.h>
> +
> +/**
> +  DEPRECATED. THIS IS ONLY HERE AS A CONVENIENCE WHILE PORTING.
> +  Mark a variable that will become read-only after leaving the DXE phase of
> +  execution. Write request coming from SMM environment through
> +  EFI_SMM_VARIABLE_PROTOCOL is allowed.
> +
> +  @param[in] This          The VARIABLE_LOCK_PROTOCOL instance.
> +  @param[in] VariableName  A pointer to the variable name that will be made
> +                           read-only subsequently.
> +  @param[in] VendorGuid    A pointer to the vendor GUID that will be made
> +                           read-only subsequently.
> +
> +  @retval EFI_SUCCESS           The variable specified by the VariableName and
> +                                the VendorGuid was marked as pending to be
> +                                read-only.
> +  @retval EFI_INVALID_PARAMETER VariableName or VendorGuid is NULL.
> +                                Or VariableName is an empty string.
> +  @retval EFI_ACCESS_DENIED     EFI_END_OF_DXE_EVENT_GROUP_GUID or
> +                                EFI_EVENT_GROUP_READY_TO_BOOT has already been
> +                                signaled.
> +  @retval EFI_OUT_OF_RESOURCES  There is not enough resource to hold the
> lock
> +                                request.
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableLockRequestToLock (
> +  IN CONST EDKII_VARIABLE_LOCK_PROTOCOL  *This,
> +  IN CHAR16                              *VariableName,
> +  IN EFI_GUID                            *VendorGuid
> +  )
> +{
> +  EFI_STATUS             Status;
> +  VARIABLE_POLICY_ENTRY  *NewPolicy;
> +
> +  DEBUG ((DEBUG_WARN, "!!! DEPRECATED INTERFACE !!! %a() will go away
> soon!\n", __FUNCTION__));
> +  DEBUG ((DEBUG_WARN, "!!! DEPRECATED INTERFACE !!! Please move to use
> Variable Policy!\n"));
> +  DEBUG ((DEBUG_WARN, "!!! DEPRECATED INTERFACE !!! Variable: %g %s\n",
> VendorGuid, VariableName));
> +
> +  NewPolicy = NULL;
> +  Status    = CreateBasicVariablePolicy (
> +                VendorGuid,
> +                VariableName,
> +                VARIABLE_POLICY_NO_MIN_SIZE,
> +                VARIABLE_POLICY_NO_MAX_SIZE,
> +                VARIABLE_POLICY_NO_MUST_ATTR,
> +                VARIABLE_POLICY_NO_CANT_ATTR,
> +                VARIABLE_POLICY_TYPE_LOCK_NOW,
> +                &NewPolicy
> +                );
> +  if (!EFI_ERROR (Status)) {
> +    Status = RegisterVariablePolicy (NewPolicy);
> +
> +    //
> +    // If the error returned is EFI_ALREADY_STARTED, we need to check the
> +    // current database for the variable and see whether it's locked. If it's
> +    // locked, we're still fine, but also generate a DEBUG_WARN message so the
> +    // duplicate lock can be removed.
> +    //
> +    if (Status == EFI_ALREADY_STARTED) {
> +      Status = ValidateSetVariable (VariableName, VendorGuid, 0, 0, NULL);
> +      if (Status == EFI_WRITE_PROTECTED) {
> +        DEBUG ((DEBUG_WARN, "  Variable: %g %s is already locked!\n",
> VendorGuid, VariableName));
> +        Status = EFI_SUCCESS;
> +      } else {
> +        DEBUG ((DEBUG_ERROR, "  Variable: %g %s can not be locked!\n",
> VendorGuid, VariableName));
> +        Status = EFI_ACCESS_DENIED;
> +      }
> +    }
> +  }
> +
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "%a - Failed to lock variable %s! %r\n",
> __FUNCTION__, VariableName, Status));
> +  }
> +
> +  if (NewPolicy != NULL) {
> +    FreePool (NewPolicy);
> +  }
> +
> +  return Status;
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableNonVolat
> ile.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableNonVolat
> ile.c
> new file mode 100644
> index 000000000000..32dd9901b260
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableNonVolat
> ile.c
> @@ -0,0 +1,537 @@
> +/** @file
> +  Common variable non-volatile store routines.
> +
> +Copyright (c) 2019 - 2022, Intel Corporation. All rights reserved.<BR>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include "VariableNonVolatile.h"
> +#include "VariableParsing.h"
> +
> +extern VARIABLE_MODULE_GLOBAL  *mVariableModuleGlobal;
> +
> +/**
> +  Get non-volatile maximum variable size.
> +
> +  @return Non-volatile maximum variable size.
> +
> +**/
> +UINTN
> +GetNonVolatileMaxVariableSize (
> +  VOID
> +  )
> +{
> +  if (PcdGet32 (PcdHwErrStorageSize) != 0) {
> +    return MAX (
> +             MAX (PcdGet32 (PcdMaxVariableSize), PcdGet32
> (PcdMaxAuthVariableSize)),
> +             PcdGet32 (PcdMaxHardwareErrorVariableSize)
> +             );
> +  } else {
> +    return MAX (PcdGet32 (PcdMaxVariableSize), PcdGet32
> (PcdMaxAuthVariableSize));
> +  }
> +}
> +
> +/**
> +  Init emulated non-volatile variable store.
> +
> +  @param[out] VariableStoreBase Output pointer to emulated non-volatile
> variable store base.
> +
> +  @retval EFI_SUCCESS           Function successfully executed.
> +  @retval EFI_OUT_OF_RESOURCES  Fail to allocate enough memory resource.
> +
> +**/
> +EFI_STATUS
> +InitEmuNonVolatileVariableStore (
> +  OUT EFI_PHYSICAL_ADDRESS  *VariableStoreBase
> +  )
> +{
> +  VARIABLE_STORE_HEADER  *VariableStore;
> +  UINT32                 VariableStoreLength;
> +  BOOLEAN                FullyInitializeStore;
> +  UINT32                 HwErrStorageSize;
> +
> +  FullyInitializeStore = TRUE;
> +
> +  VariableStoreLength = PcdGet32 (PcdVariableStoreSize);
> +  ASSERT (sizeof (VARIABLE_STORE_HEADER) <= VariableStoreLength);
> +
> +  //
> +  // Allocate memory for variable store.
> +  //
> +  if (PcdGet64 (PcdEmuVariableNvStoreReserved) == 0) {
> +    VariableStore = (VARIABLE_STORE_HEADER *)AllocateRuntimePool
> (VariableStoreLength);
> +    if (VariableStore == NULL) {
> +      return EFI_OUT_OF_RESOURCES;
> +    }
> +  } else {
> +    //
> +    // A memory location has been reserved for the NV variable store.  Certain
> +    // platforms may be able to preserve a memory range across system resets,
> +    // thereby providing better NV variable emulation.
> +    //
> +    VariableStore =
> +      (VARIABLE_STORE_HEADER *)(VOID *)(UINTN)
> +      PcdGet64 (PcdEmuVariableNvStoreReserved);
> +    if ((VariableStore->Size == VariableStoreLength) &&
> +        (CompareGuid (&VariableStore->Signature,
> &gEfiAuthenticatedVariableGuid) ||
> +         CompareGuid (&VariableStore->Signature, &gEfiVariableGuid)) &&
> +        (VariableStore->Format == VARIABLE_STORE_FORMATTED) &&
> +        (VariableStore->State == VARIABLE_STORE_HEALTHY))
> +    {
> +      DEBUG ((
> +        DEBUG_INFO,
> +        "Variable Store reserved at %p appears to be valid\n",
> +        VariableStore
> +        ));
> +      FullyInitializeStore = FALSE;
> +    }
> +  }
> +
> +  if (FullyInitializeStore) {
> +    SetMem (VariableStore, VariableStoreLength, 0xff);
> +    //
> +    // Use gEfiAuthenticatedVariableGuid for potential auth variable support.
> +    //
> +    CopyGuid (&VariableStore->Signature, &gEfiAuthenticatedVariableGuid);
> +    VariableStore->Size      = VariableStoreLength;
> +    VariableStore->Format    = VARIABLE_STORE_FORMATTED;
> +    VariableStore->State     = VARIABLE_STORE_HEALTHY;
> +    VariableStore->Reserved  = 0;
> +    VariableStore->Reserved1 = 0;
> +  }
> +
> +  *VariableStoreBase = (EFI_PHYSICAL_ADDRESS)(UINTN)VariableStore;
> +
> +  HwErrStorageSize = PcdGet32 (PcdHwErrStorageSize);
> +
> +  //
> +  // Note that in EdkII variable driver implementation, Hardware Error Record
> type variable
> +  // is stored with common variable in the same NV region. So the platform
> integrator should
> +  // ensure that the value of PcdHwErrStorageSize is less than the value of
> +  // (VariableStoreLength - sizeof (VARIABLE_STORE_HEADER)).
> +  //
> +  ASSERT (HwErrStorageSize < (VariableStoreLength - sizeof
> (VARIABLE_STORE_HEADER)));
> +
> +  mVariableModuleGlobal->CommonVariableSpace        =
> ((UINTN)VariableStoreLength - sizeof (VARIABLE_STORE_HEADER) -
> HwErrStorageSize);
> +  mVariableModuleGlobal->CommonMaxUserVariableSpace =
> mVariableModuleGlobal->CommonVariableSpace;
> +  mVariableModuleGlobal->CommonRuntimeVariableSpace =
> mVariableModuleGlobal->CommonVariableSpace;
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +
> +  Create a dummy variable used to fill the gap in NV variable storage caused by
> +  the invalid variables found in HMAC verification phase.
> +
> +  @param[out] Variable    Variable buffer.
> +  @param[in]  Name        Variable Name.
> +  @param[in]  Guid        Vendor GUID of the variable.
> +  @param[in]  Size        Whole size of the variable requested.
> +  @param[in]  AuthFlag    Variable format flag.
> +
> +**/
> +STATIC
> +VOID
> +CreateDummyVariable (
> +  OUT VARIABLE_HEADER  *Variable,
> +  IN  CHAR16           *Name,
> +  IN  EFI_GUID         *Guid,
> +  IN  UINT32           Size,
> +  IN  BOOLEAN          AuthFlag
> +  )
> +{
> +  AUTHENTICATED_VARIABLE_HEADER  *AuthVariable;
> +
> +  ASSERT (Variable != NULL);
> +
> +  if (Name == NULL) {
> +    Name = L"Dummy";
> +  }
> +
> +  if (AuthFlag) {
> +    AuthVariable = (AUTHENTICATED_VARIABLE_HEADER *)Variable;
> +
> +    AuthVariable->StartId    = VARIABLE_DATA;
> +    AuthVariable->State      = VAR_ADDED & VAR_DELETED;
> +    AuthVariable->Attributes = EFI_VARIABLE_NON_VOLATILE;
> +    AuthVariable->NameSize   = (UINT32)StrSize (Name);
> +    AuthVariable->DataSize   = Size - sizeof
> (AUTHENTICATED_VARIABLE_HEADER)
> +                               - AuthVariable->NameSize;
> +    if (Guid != NULL) {
> +      CopyMem ((VOID *)&AuthVariable->VendorGuid, (VOID *)Guid, sizeof
> (EFI_GUID));
> +    }
> +
> +    CopyMem (GetVariableNamePtr (Variable, AuthFlag), (VOID *)Name,
> AuthVariable->NameSize);
> +  } else {
> +    Variable->StartId    = VARIABLE_DATA;
> +    Variable->State      = VAR_ADDED & VAR_DELETED;
> +    Variable->Attributes = EFI_VARIABLE_NON_VOLATILE;
> +    Variable->NameSize   = (UINT32)StrSize (Name);
> +    Variable->DataSize   = Size - sizeof (VARIABLE_HEADER) - Variable-
> >NameSize;
> +    if (Guid != NULL) {
> +      CopyMem ((VOID *)&Variable->VendorGuid, (VOID *)Guid, sizeof
> (EFI_GUID));
> +    }
> +
> +    CopyMem (GetVariableNamePtr (Variable, AuthFlag), (VOID *)Name,
> Variable->NameSize);
> +  }
> +}
> +
> +/**
> +
> +  Init protected variable store.
> +
> +  @param[in, out]  VariableStore  Pointer to real protected variable store base.
> +
> +**/
> +EFI_STATUS
> +InitProtectedVariableStore (
> +  IN  OUT VARIABLE_STORE_HEADER  *VariableStore
> +  )
> +{
> +  EFI_STATUS               Status;
> +  PROTECTED_VARIABLE_INFO  VarInfo;
> +  UINTN                    Size;
> +  UINTN                    Index;
> +  BOOLEAN                  AuthFlag;
> +  EFI_PHYSICAL_ADDRESS     NextVariableStore;
> +  EFI_PHYSICAL_ADDRESS     *VarList;
> +  UINTN                    NumVars;
> +  UINTN                    CurrVar;
> +
> +  SetMem (
> +    (UINT8 *)VariableStore + sizeof (VARIABLE_STORE_HEADER),
> +    VariableStore->Size - sizeof (VARIABLE_STORE_HEADER),
> +    0xFF
> +    );
> +  Index = sizeof (VARIABLE_STORE_HEADER);
> +
> +  VarList = NULL;
> +  NumVars = 0;
> +  ProtectedVariableLibGetSortedList (&VarList, &NumVars);
> +
> +  //
> +  // Search variable in the order of StoreIndex
> +  //
> +  ZeroMem (&VarInfo, sizeof (VarInfo));
> +
> +  for (CurrVar = 0; CurrVar < NumVars; CurrVar++) {
> +    VarInfo.Buffer     = NULL;
> +    VarInfo.StoreIndex = VarList[CurrVar];
> +    if (VarInfo.StoreIndex == VAR_INDEX_INVALID) {
> +      break;
> +    }
> +
> +    Status = ProtectedVariableLibFind (&VarInfo);
> +    if (EFI_ERROR (Status)) {
> +      break;
> +    }
> +
> +    ASSERT (VarInfo.Buffer != NULL);
> +
> +    AuthFlag = VarInfo.Flags.Auth;
> +    if (VarInfo.StoreIndex == VAR_INDEX_INVALID) {
> +      continue;
> +    } else {
> +      ASSERT (VarInfo.StoreIndex == HEADER_ALIGN (VarInfo.StoreIndex));
> +      ASSERT (VarInfo.StoreIndex < (VariableStore->Size - sizeof
> (VARIABLE_STORE_HEADER)));
> +      ASSERT ((VariableStore->Size - VarInfo.StoreIndex) > GetVariableHeaderSize
> (AuthFlag));
> +    }
> +
> +    //
> +    // Fill gap caused by invalid variable.
> +    //
> +    if (VarInfo.StoreIndex > Index) {
> +      Size = (UINTN)VarInfo.StoreIndex - Index;
> +      CreateDummyVariable (
> +        (VARIABLE_HEADER *)((UINT8 *)VariableStore + Index),
> +        NULL,
> +        NULL,
> +        (UINT32)Size,
> +        AuthFlag
> +        );
> +      Index += Size;
> +    }
> +
> +    Size = (UINTN)GetNextVariablePtr (VarInfo.Buffer, AuthFlag)
> +           - (UINTN)VarInfo.Buffer;
> +    CopyMem ((UINT8 *)VariableStore + VarInfo.StoreIndex, VarInfo.Buffer,
> Size);
> +
> +    Index += Size;
> +    Index  = HEADER_ALIGN (Index);
> +
> +    NextVariableStore = (EFI_PHYSICAL_ADDRESS)((UINTN)VariableStore +
> VarInfo.StoreIndex + Size);
> +  }
> +
> +  //
> +  // Search variable in the order of StoreIndex
> +  //
> +  ZeroMem (&VarInfo, sizeof (VarInfo));
> +  for ( ; CurrVar < NumVars; CurrVar++) {
> +    VarInfo.Buffer     = NULL;
> +    VarInfo.StoreIndex = VarList[CurrVar];
> +    Status             = ProtectedVariableLibFind (&VarInfo);
> +    if (EFI_ERROR (Status)) {
> +      break;
> +    }
> +
> +    ASSERT (VarInfo.Buffer != NULL);
> +
> +    AuthFlag = VarInfo.Flags.Auth;
> +    if (VarInfo.StoreIndex == VAR_INDEX_INVALID) {
> +      Size = (UINTN)GetNextVariablePtr (VarInfo.Buffer, AuthFlag)
> +             - (UINTN)VarInfo.Buffer;
> +      CopyMem ((VOID *)(UINTN)NextVariableStore, VarInfo.Buffer, Size);
> +      Status            = ProtectedVariableLibRefresh (VarInfo.Buffer, 0,
> NextVariableStore - (UINTN)VariableStore, FALSE);
> +      NextVariableStore = NextVariableStore + Size;
> +    }
> +  }
> +
> +  if (Status == EFI_UNSUPPORTED) {
> +    return Status;
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Init real non-volatile variable store.
> +
> +  @param[out] VariableStoreBase Output pointer to real non-volatile variable
> store base.
> +
> +  @retval EFI_SUCCESS           Function successfully executed.
> +  @retval EFI_OUT_OF_RESOURCES  Fail to allocate enough memory resource.
> +  @retval EFI_VOLUME_CORRUPTED  Variable Store or Firmware Volume for
> Variable Store is corrupted.
> +
> +**/
> +EFI_STATUS
> +InitRealNonVolatileVariableStore (
> +  OUT EFI_PHYSICAL_ADDRESS  *VariableStoreBase
> +  )
> +{
> +  EFI_FIRMWARE_VOLUME_HEADER            *FvHeader;
> +  VARIABLE_STORE_HEADER                 *VariableStore;
> +  UINT32                                VariableStoreLength;
> +  EFI_HOB_GUID_TYPE                     *GuidHob;
> +  EFI_PHYSICAL_ADDRESS                  NvStorageBase;
> +  UINT8                                 *NvStorageData;
> +  UINT32                                NvStorageSize;
> +  UINT64                                NvStorageSize64;
> +  FAULT_TOLERANT_WRITE_LAST_WRITE_DATA  *FtwLastWriteData;
> +  UINT32                                BackUpOffset;
> +  UINT32                                BackUpSize;
> +  UINT32                                HwErrStorageSize;
> +  UINT32                                MaxUserNvVariableSpaceSize;
> +  UINT32                                BoottimeReservedNvVariableSpaceSize;
> +  EFI_STATUS                            Status;
> +  VOID                                  *FtwProtocol;
> +
> +  mVariableModuleGlobal->FvbInstance = NULL;
> +
> +  Status = GetVariableFlashNvStorageInfo (&NvStorageBase,
> &NvStorageSize64);
> +  ASSERT_EFI_ERROR (Status);
> +
> +  Status = SafeUint64ToUint32 (NvStorageSize64, &NvStorageSize);
> +  // This driver currently assumes the size will be UINT32 so assert the value is
> safe for now.
> +  ASSERT_EFI_ERROR (Status);
> +
> +  ASSERT (NvStorageBase != 0);
> +
> +  //
> +  // Allocate runtime memory used for a memory copy of the FLASH region.
> +  // Keep the memory and the FLASH in sync as updates occur.
> +  //
> +  NvStorageData = AllocateRuntimeZeroPool (NvStorageSize);
> +  if (NvStorageData == NULL) {
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +
> +  //
> +  // Copy NV storage data to the memory buffer.
> +  //
> +  CopyMem (NvStorageData, (UINT8 *)(UINTN)NvStorageBase, NvStorageSize);
> +
> +  Status = GetFtwProtocol ((VOID **)&FtwProtocol);
> +  //
> +  // If FTW protocol has been installed, no need to check FTW last write data
> hob.
> +  //
> +  if (EFI_ERROR (Status)) {
> +    //
> +    // Check the FTW last write data hob.
> +    //
> +    GuidHob = GetFirstGuidHob (&gEdkiiFaultTolerantWriteGuid);
> +    if (GuidHob != NULL) {
> +      FtwLastWriteData = (FAULT_TOLERANT_WRITE_LAST_WRITE_DATA
> *)GET_GUID_HOB_DATA (GuidHob);
> +      if (FtwLastWriteData->TargetAddress == NvStorageBase) {
> +        DEBUG ((DEBUG_INFO, "Variable: NV storage is backed up in spare block:
> 0x%x\n", (UINTN)FtwLastWriteData->SpareAddress));
> +        //
> +        // Copy the backed up NV storage data to the memory buffer from spare
> block.
> +        //
> +        CopyMem (NvStorageData, (UINT8 *)(UINTN)(FtwLastWriteData-
> >SpareAddress), NvStorageSize);
> +      } else if ((FtwLastWriteData->TargetAddress > NvStorageBase) &&
> +                 (FtwLastWriteData->TargetAddress < (NvStorageBase +
> NvStorageSize)))
> +      {
> +        //
> +        // Flash NV storage from the Offset is backed up in spare block.
> +        //
> +        BackUpOffset = (UINT32)(FtwLastWriteData->TargetAddress -
> NvStorageBase);
> +        BackUpSize   = NvStorageSize - BackUpOffset;
> +        DEBUG ((DEBUG_INFO, "Variable: High partial NV storage from offset: %x
> is backed up in spare block: 0x%x\n", BackUpOffset, (UINTN)FtwLastWriteData-
> >SpareAddress));
> +        //
> +        // Copy the partial backed up NV storage data to the memory buffer from
> spare block.
> +        //
> +        CopyMem (NvStorageData + BackUpOffset, (UINT8
> *)(UINTN)FtwLastWriteData->SpareAddress, BackUpSize);
> +      }
> +    }
> +  }
> +
> +  FvHeader = (EFI_FIRMWARE_VOLUME_HEADER *)NvStorageData;
> +
> +  //
> +  // Check if the Firmware Volume is not corrupted
> +  //
> +  if ((FvHeader->Signature != EFI_FVH_SIGNATURE) || (!CompareGuid
> (&gEfiSystemNvDataFvGuid, &FvHeader->FileSystemGuid))) {
> +    FreePool (NvStorageData);
> +    DEBUG ((DEBUG_ERROR, "Firmware Volume for Variable Store is
> corrupted\n"));
> +    return EFI_VOLUME_CORRUPTED;
> +  }
> +
> +  VariableStore       = (VARIABLE_STORE_HEADER *)((UINTN)FvHeader +
> FvHeader->HeaderLength);
> +  VariableStoreLength = NvStorageSize - FvHeader->HeaderLength;
> +  ASSERT (sizeof (VARIABLE_STORE_HEADER) <= VariableStoreLength);
> +  ASSERT (VariableStore->Size == VariableStoreLength);
> +
> +  //
> +  // Check if the Variable Store header is not corrupted
> +  //
> +  if (GetVariableStoreStatus (VariableStore) != EfiValid) {
> +    FreePool (NvStorageData);
> +    DEBUG ((DEBUG_ERROR, "Variable Store header is corrupted\n"));
> +    return EFI_VOLUME_CORRUPTED;
> +  }
> +
> +  //
> +  // Overwrite the store with verified copy of protected variables, if enabled.
> +  //
> +  Status = InitProtectedVariableStore (VariableStore);
> +  if ((Status != EFI_SUCCESS) && (Status != EFI_UNSUPPORTED)) {
> +    FreePool (NvStorageData);
> +    DEBUG ((DEBUG_ERROR, "Variable integrity might have been
> compromised\n"));
> +    return Status;
> +  }
> +
> +  mNvFvHeaderCache = FvHeader;
> +
> +  *VariableStoreBase = (EFI_PHYSICAL_ADDRESS)(UINTN)VariableStore;
> +
> +  HwErrStorageSize                    = PcdGet32 (PcdHwErrStorageSize);
> +  MaxUserNvVariableSpaceSize          = PcdGet32
> (PcdMaxUserNvVariableSpaceSize);
> +  BoottimeReservedNvVariableSpaceSize = PcdGet32
> (PcdBoottimeReservedNvVariableSpaceSize);
> +
> +  //
> +  // Note that in EdkII variable driver implementation, Hardware Error Record
> type variable
> +  // is stored with common variable in the same NV region. So the platform
> integrator should
> +  // ensure that the value of PcdHwErrStorageSize is less than the value of
> +  // (VariableStoreLength - sizeof (VARIABLE_STORE_HEADER)).
> +  //
> +  ASSERT (HwErrStorageSize < (VariableStoreLength - sizeof
> (VARIABLE_STORE_HEADER)));
> +  //
> +  // Ensure that the value of PcdMaxUserNvVariableSpaceSize is less than the
> value of
> +  // (VariableStoreLength - sizeof (VARIABLE_STORE_HEADER)) - PcdGet32
> (PcdHwErrStorageSize).
> +  //
> +  ASSERT (MaxUserNvVariableSpaceSize < (VariableStoreLength - sizeof
> (VARIABLE_STORE_HEADER) - HwErrStorageSize));
> +  //
> +  // Ensure that the value of PcdBoottimeReservedNvVariableSpaceSize is less
> than the value of
> +  // (VariableStoreLength - sizeof (VARIABLE_STORE_HEADER)) - PcdGet32
> (PcdHwErrStorageSize).
> +  //
> +  ASSERT (BoottimeReservedNvVariableSpaceSize < (VariableStoreLength -
> sizeof (VARIABLE_STORE_HEADER) - HwErrStorageSize));
> +
> +  mVariableModuleGlobal->CommonVariableSpace        =
> ((UINTN)VariableStoreLength - sizeof (VARIABLE_STORE_HEADER) -
> HwErrStorageSize);
> +  mVariableModuleGlobal->CommonMaxUserVariableSpace =
> ((MaxUserNvVariableSpaceSize != 0) ? MaxUserNvVariableSpaceSize :
> mVariableModuleGlobal->CommonVariableSpace);
> +  mVariableModuleGlobal->CommonRuntimeVariableSpace =
> mVariableModuleGlobal->CommonVariableSpace -
> BoottimeReservedNvVariableSpaceSize;
> +
> +  DEBUG ((
> +    DEBUG_INFO,
> +    "Variable driver common space: 0x%x 0x%x 0x%x\n",
> +    mVariableModuleGlobal->CommonVariableSpace,
> +    mVariableModuleGlobal->CommonMaxUserVariableSpace,
> +    mVariableModuleGlobal->CommonRuntimeVariableSpace
> +    ));
> +
> +  //
> +  // The max NV variable size should be < (VariableStoreLength - sizeof
> (VARIABLE_STORE_HEADER)).
> +  //
> +  ASSERT (GetNonVolatileMaxVariableSize () < (VariableStoreLength - sizeof
> (VARIABLE_STORE_HEADER)));
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Init non-volatile variable store.
> +
> +  @retval EFI_SUCCESS           Function successfully executed.
> +  @retval EFI_OUT_OF_RESOURCES  Fail to allocate enough memory resource.
> +  @retval EFI_VOLUME_CORRUPTED  Variable Store or Firmware Volume for
> Variable Store is corrupted.
> +
> +**/
> +EFI_STATUS
> +InitNonVolatileVariableStore (
> +  VOID
> +  )
> +{
> +  VARIABLE_HEADER       *Variable;
> +  VARIABLE_HEADER       *NextVariable;
> +  EFI_PHYSICAL_ADDRESS  VariableStoreBase;
> +  UINTN                 VariableSize;
> +  EFI_STATUS            Status;
> +
> +  if (PcdGetBool (PcdEmuVariableNvModeEnable)) {
> +    Status = InitEmuNonVolatileVariableStore (&VariableStoreBase);
> +    if (EFI_ERROR (Status)) {
> +      return Status;
> +    }
> +
> +    mVariableModuleGlobal->VariableGlobal.EmuNvMode = TRUE;
> +    DEBUG ((DEBUG_INFO, "Variable driver will work at emulated non-volatile
> variable mode!\n"));
> +  } else {
> +    Status = InitRealNonVolatileVariableStore (&VariableStoreBase);
> +    if (EFI_ERROR (Status)) {
> +      return Status;
> +    }
> +
> +    mVariableModuleGlobal->VariableGlobal.EmuNvMode = FALSE;
> +  }
> +
> +  mVariableModuleGlobal->VariableGlobal.NonVolatileVariableBase =
> VariableStoreBase;
> +  mNvVariableCache                                              = (VARIABLE_STORE_HEADER
> *)(UINTN)VariableStoreBase;
> +  mVariableModuleGlobal->VariableGlobal.AuthFormat              =
> (BOOLEAN)(CompareGuid (&mNvVariableCache->Signature,
> &gEfiAuthenticatedVariableGuid));
> +
> +  mVariableModuleGlobal->MaxVariableSize     = PcdGet32
> (PcdMaxVariableSize);
> +  mVariableModuleGlobal->MaxAuthVariableSize = ((PcdGet32
> (PcdMaxAuthVariableSize) != 0) ? PcdGet32 (PcdMaxAuthVariableSize) :
> mVariableModuleGlobal->MaxVariableSize);
> +
> +  //
> +  // Parse non-volatile variable data and get last variable offset.
> +  //
> +  Variable = GetStartPointer (mNvVariableCache);
> +  while (IsValidVariableHeader (
> +           Variable,
> +           GetEndPointer (mNvVariableCache),
> +           mVariableModuleGlobal->VariableGlobal.AuthFormat
> +           ))
> +  {
> +    NextVariable = GetNextVariablePtr (Variable, mVariableModuleGlobal-
> >VariableGlobal.AuthFormat);
> +    VariableSize = (UINTN)NextVariable - (UINTN)Variable;
> +    if ((Variable->Attributes & (EFI_VARIABLE_NON_VOLATILE |
> EFI_VARIABLE_HARDWARE_ERROR_RECORD)) ==
> (EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_HARDWARE_ERROR_RECORD))
> {
> +      mVariableModuleGlobal->HwErrVariableTotalSize += VariableSize;
> +    } else {
> +      mVariableModuleGlobal->CommonVariableTotalSize += VariableSize;
> +    }
> +
> +    Variable = NextVariable;
> +  }
> +
> +  mVariableModuleGlobal->NonVolatileLastVariableOffset = (UINTN)Variable -
> (UINTN)mNvVariableCache;
> +
> +  return EFI_SUCCESS;
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableParsing.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableParsing.c
> new file mode 100644
> index 000000000000..be3f59341c1e
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableParsing.c
> @@ -0,0 +1,1110 @@
> +/** @file
> +  Functions in this module are associated with variable parsing operations and
> +  are intended to be usable across variable driver source files.
> +
> +Copyright (c) 2019 - 2022, Intel Corporation. All rights reserved.<BR>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include "Variable.h"
> +#include "VariableParsing.h"
> +
> +/**
> +
> +  This code checks if variable header is valid or not.
> +
> +  @param[in] Variable           Pointer to the Variable Header.
> +  @param[in] VariableStoreEnd   Pointer to the Variable Store End.
> +  @param[in] AuthFormat         TRUE indicates authenticated variables are used.
> +                                FALSE indicates authenticated variables are not used.
> +
> +  @retval TRUE              Variable header is valid.
> +  @retval FALSE             Variable header is not valid.
> +
> +**/
> +BOOLEAN
> +IsValidVariableHeader (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  VARIABLE_HEADER  *VariableStoreEnd,
> +  IN  BOOLEAN          AuthFormat
> +  )
> +{
> +  if (  (Variable == NULL)
> +     || (((UINTN)Variable + GetVariableHeaderSize (AuthFormat)) >=
> (UINTN)VariableStoreEnd)
> +     || (Variable->StartId != VARIABLE_DATA))
> +  {
> +    //
> +    // Variable is NULL or has reached the end of variable store,
> +    // or the StartId is not correct.
> +    //
> +    return FALSE;
> +  }
> +
> +  return TRUE;
> +}
> +
> +/**
> +
> +  This code gets the current status of Variable Store.
> +
> +  @param[in] VarStoreHeader  Pointer to the Variable Store Header.
> +
> +  @retval EfiRaw         Variable store status is raw.
> +  @retval EfiValid       Variable store status is valid.
> +  @retval EfiInvalid     Variable store status is invalid.
> +
> +**/
> +VARIABLE_STORE_STATUS
> +GetVariableStoreStatus (
> +  IN VARIABLE_STORE_HEADER  *VarStoreHeader
> +  )
> +{
> +  if ((CompareGuid (&VarStoreHeader->Signature,
> &gEfiAuthenticatedVariableGuid) ||
> +       CompareGuid (&VarStoreHeader->Signature, &gEfiVariableGuid)) &&
> +      (VarStoreHeader->Format == VARIABLE_STORE_FORMATTED) &&
> +      (VarStoreHeader->State == VARIABLE_STORE_HEALTHY)
> +      )
> +  {
> +    return EfiValid;
> +  } else if ((((UINT32 *)(&VarStoreHeader->Signature))[0] == 0xffffffff) &&
> +             (((UINT32 *)(&VarStoreHeader->Signature))[1] == 0xffffffff) &&
> +             (((UINT32 *)(&VarStoreHeader->Signature))[2] == 0xffffffff) &&
> +             (((UINT32 *)(&VarStoreHeader->Signature))[3] == 0xffffffff) &&
> +             (VarStoreHeader->Size == 0xffffffff) &&
> +             (VarStoreHeader->Format == 0xff) &&
> +             (VarStoreHeader->State == 0xff)
> +             )
> +  {
> +    return EfiRaw;
> +  } else {
> +    return EfiInvalid;
> +  }
> +}
> +
> +/**
> +  This code gets the size of variable header.
> +
> +  @param[in]  AuthFormat    TRUE indicates authenticated variables are used.
> +                            FALSE indicates authenticated variables are not used.
> +
> +  @return Size of variable header in bytes in type UINTN.
> +
> +**/
> +UINTN
> +GetVariableHeaderSize (
> +  IN  BOOLEAN  AuthFormat
> +  )
> +{
> +  UINTN  Value;
> +
> +  if (AuthFormat) {
> +    Value = sizeof (AUTHENTICATED_VARIABLE_HEADER);
> +  } else {
> +    Value = sizeof (VARIABLE_HEADER);
> +  }
> +
> +  return Value;
> +}
> +
> +/**
> +
> +  This code gets the size of name of variable.
> +
> +  @param[in]  Variable      Pointer to the variable header.
> +  @param[in]  AuthFormat    TRUE indicates authenticated variables are used.
> +                            FALSE indicates authenticated variables are not used.
> +
> +  @return UINTN          Size of variable in bytes.
> +
> +**/
> +UINTN
> +NameSizeOfVariable (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  BOOLEAN          AuthFormat
> +  )
> +{
> +  AUTHENTICATED_VARIABLE_HEADER  *AuthVariable;
> +
> +  AuthVariable = (AUTHENTICATED_VARIABLE_HEADER *)Variable;
> +  if (AuthFormat) {
> +    if ((AuthVariable->State == (UINT8)(-1)) ||
> +        (AuthVariable->DataSize == (UINT32)(-1)) ||
> +        (AuthVariable->NameSize == (UINT32)(-1)) ||
> +        (AuthVariable->Attributes == (UINT32)(-1)))
> +    {
> +      return 0;
> +    }
> +
> +    return (UINTN)AuthVariable->NameSize;
> +  } else {
> +    if ((Variable->State == (UINT8)(-1)) ||
> +        (Variable->DataSize == (UINT32)(-1)) ||
> +        (Variable->NameSize == (UINT32)(-1)) ||
> +        (Variable->Attributes == (UINT32)(-1)))
> +    {
> +      return 0;
> +    }
> +
> +    return (UINTN)Variable->NameSize;
> +  }
> +}
> +
> +/**
> +  This code sets the size of name of variable.
> +
> +  @param[in]  Variable      Pointer to the Variable Header.
> +  @param[in]  NameSize      Name size to set.
> +  @param[in]  AuthFormat    TRUE indicates authenticated variables are used.
> +                            FALSE indicates authenticated variables are not used.
> +
> +**/
> +VOID
> +SetNameSizeOfVariable (
> +  IN VARIABLE_HEADER  *Variable,
> +  IN UINTN            NameSize,
> +  IN BOOLEAN          AuthFormat
> +  )
> +{
> +  AUTHENTICATED_VARIABLE_HEADER  *AuthVariable;
> +
> +  AuthVariable = (AUTHENTICATED_VARIABLE_HEADER *)Variable;
> +  if (AuthFormat) {
> +    AuthVariable->NameSize = (UINT32)NameSize;
> +  } else {
> +    Variable->NameSize = (UINT32)NameSize;
> +  }
> +}
> +
> +/**
> +
> +  This code gets the size of variable data.
> +
> +  @param[in]  Variable      Pointer to the Variable Header.
> +  @param[in]  AuthFormat    TRUE indicates authenticated variables are used.
> +                            FALSE indicates authenticated variables are not used.
> +
> +  @return Size of variable in bytes.
> +
> +**/
> +UINTN
> +DataSizeOfVariable (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  BOOLEAN          AuthFormat
> +  )
> +{
> +  AUTHENTICATED_VARIABLE_HEADER  *AuthVariable;
> +
> +  AuthVariable = (AUTHENTICATED_VARIABLE_HEADER *)Variable;
> +  if (AuthFormat) {
> +    if ((AuthVariable->State == (UINT8)(-1)) ||
> +        (AuthVariable->DataSize == (UINT32)(-1)) ||
> +        (AuthVariable->NameSize == (UINT32)(-1)) ||
> +        (AuthVariable->Attributes == (UINT32)(-1)))
> +    {
> +      return 0;
> +    }
> +
> +    return (UINTN)AuthVariable->DataSize;
> +  } else {
> +    if ((Variable->State == (UINT8)(-1)) ||
> +        (Variable->DataSize == (UINT32)(-1)) ||
> +        (Variable->NameSize == (UINT32)(-1)) ||
> +        (Variable->Attributes == (UINT32)(-1)))
> +    {
> +      return 0;
> +    }
> +
> +    return (UINTN)Variable->DataSize;
> +  }
> +}
> +
> +/**
> +  This code sets the size of variable data.
> +
> +  @param[in] Variable   Pointer to the Variable Header.
> +  @param[in] DataSize   Data size to set.
> +  @param[in] AuthFormat TRUE indicates authenticated variables are used.
> +                        FALSE indicates authenticated variables are not used.
> +
> +**/
> +VOID
> +SetDataSizeOfVariable (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  UINTN            DataSize,
> +  IN  BOOLEAN          AuthFormat
> +  )
> +{
> +  AUTHENTICATED_VARIABLE_HEADER  *AuthVariable;
> +
> +  AuthVariable = (AUTHENTICATED_VARIABLE_HEADER *)Variable;
> +  if (AuthFormat) {
> +    AuthVariable->DataSize = (UINT32)DataSize;
> +  } else {
> +    Variable->DataSize = (UINT32)DataSize;
> +  }
> +}
> +
> +/**
> +
> +  This code gets the pointer to the variable name.
> +
> +  @param[in] Variable     Pointer to the Variable Header.
> +  @param[in] AuthFormat   TRUE indicates authenticated variables are used.
> +                          FALSE indicates authenticated variables are not used.
> +
> +  @return Pointer to Variable Name which is Unicode encoding.
> +
> +**/
> +CHAR16 *
> +GetVariableNamePtr (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  BOOLEAN          AuthFormat
> +  )
> +{
> +  return (CHAR16 *)((UINTN)Variable + GetVariableHeaderSize (AuthFormat));
> +}
> +
> +/**
> +  This code gets the pointer to the variable guid.
> +
> +  @param[in] Variable     Pointer to the Variable Header.
> +  @param[in] AuthFormat   TRUE indicates authenticated variables are used.
> +                          FALSE indicates authenticated variables are not used.
> +
> +  @return A EFI_GUID* pointer to Vendor Guid.
> +
> +**/
> +EFI_GUID *
> +GetVendorGuidPtr (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  BOOLEAN          AuthFormat
> +  )
> +{
> +  AUTHENTICATED_VARIABLE_HEADER  *AuthVariable;
> +
> +  AuthVariable = (AUTHENTICATED_VARIABLE_HEADER *)Variable;
> +  if (AuthFormat) {
> +    return &AuthVariable->VendorGuid;
> +  } else {
> +    return &Variable->VendorGuid;
> +  }
> +}
> +
> +/**
> +
> +  This code gets the pointer to the variable data.
> +
> +  @param[in] Variable     Pointer to the Variable Header.
> +  @param[in] AuthFormat   TRUE indicates authenticated variables are used.
> +                          FALSE indicates authenticated variables are not used.
> +
> +  @return Pointer to Variable Data.
> +
> +**/
> +UINT8 *
> +GetVariableDataPtr (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  BOOLEAN          AuthFormat
> +  )
> +{
> +  UINTN  Value;
> +
> +  //
> +  // Be careful about pad size for alignment.
> +  //
> +  Value  =  (UINTN)GetVariableNamePtr (Variable, AuthFormat);
> +  Value += NameSizeOfVariable (Variable, AuthFormat);
> +  Value += GET_PAD_SIZE (NameSizeOfVariable (Variable, AuthFormat));
> +
> +  return (UINT8 *)Value;
> +}
> +
> +/**
> +  This code gets the variable data offset related to variable header.
> +
> +  @param[in] Variable     Pointer to the Variable Header.
> +  @param[in] AuthFormat   TRUE indicates authenticated variables are used.
> +                          FALSE indicates authenticated variables are not used.
> +
> +  @return Variable Data offset.
> +
> +**/
> +UINTN
> +GetVariableDataOffset (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  BOOLEAN          AuthFormat
> +  )
> +{
> +  UINTN  Value;
> +
> +  //
> +  // Be careful about pad size for alignment
> +  //
> +  Value  = GetVariableHeaderSize (AuthFormat);
> +  Value += NameSizeOfVariable (Variable, AuthFormat);
> +  Value += GET_PAD_SIZE (NameSizeOfVariable (Variable, AuthFormat));
> +
> +  return Value;
> +}
> +
> +/**
> +  Get variable data payload.
> +
> +  @param[in]      Variable     Pointer to the Variable Header.
> +  @param[in,out]  Data         Pointer to buffer used to store the variable data.
> +  @param[in,out]  DataSize     Size of buffer passed by Data.
> +                               Size of data copied into Data buffer.
> +  @param[in]      AuthFlag     Auth-variable indicator.
> +
> +  @return EFI_SUCCESS             Data was fetched.
> +  @return EFI_INVALID_PARAMETER   DataSize is NULL.
> +  @return EFI_BUFFER_TOO_SMALL    DataSize is smaller than size of variable
> data.
> +
> +**/
> +EFI_STATUS
> +GetVariableData (
> +  IN      VARIABLE_HEADER  *Variable,
> +  IN  OUT VOID             *Data,
> +  IN  OUT UINT32           *DataSize,
> +  IN      BOOLEAN          AuthFlag
> +  )
> +{
> +  UINT32  Size;
> +
> +  if (DataSize == NULL) {
> +    ASSERT (DataSize != NULL);
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  Size = (UINT32)DataSizeOfVariable (Variable, AuthFlag);
> +  if (*DataSize < Size) {
> +    *DataSize = Size;
> +    return EFI_BUFFER_TOO_SMALL;
> +  }
> +
> +  if (Data == NULL) {
> +    ASSERT (Data != NULL);
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  CopyMem (Data, GetVariableDataPtr (Variable, AuthFlag), Size);
> +  *DataSize = Size;
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +
> +  This code gets the pointer to the next variable header.
> +
> +  @param[in] Variable     Pointer to the Variable Header.
> +  @param[in] AuthFormat   TRUE indicates authenticated variables are used.
> +                          FALSE indicates authenticated variables are not used.
> +
> +  @return Pointer to next variable header.
> +
> +**/
> +VARIABLE_HEADER *
> +GetNextVariablePtr (
> +  IN  VARIABLE_HEADER  *Variable,
> +  IN  BOOLEAN          AuthFormat
> +  )
> +{
> +  UINTN  Value;
> +
> +  Value  =  (UINTN)GetVariableDataPtr (Variable, AuthFormat);
> +  Value += DataSizeOfVariable (Variable, AuthFormat);
> +  Value += GET_PAD_SIZE (DataSizeOfVariable (Variable, AuthFormat));
> +
> +  //
> +  // Be careful about pad size for alignment.
> +  //
> +  return (VARIABLE_HEADER *)HEADER_ALIGN (Value);
> +}
> +
> +/**
> +
> +  Gets the pointer to the first variable header in given variable store area.
> +
> +  @param[in] VarStoreHeader  Pointer to the Variable Store Header.
> +
> +  @return Pointer to the first variable header.
> +
> +**/
> +VARIABLE_HEADER *
> +GetStartPointer (
> +  IN VARIABLE_STORE_HEADER  *VarStoreHeader
> +  )
> +{
> +  //
> +  // The start of variable store.
> +  //
> +  return (VARIABLE_HEADER *)HEADER_ALIGN (VarStoreHeader + 1);
> +}
> +
> +/**
> +
> +  Gets the pointer to the end of the variable storage area.
> +
> +  This function gets pointer to the end of the variable storage
> +  area, according to the input variable store header.
> +
> +  @param[in] VarStoreHeader  Pointer to the Variable Store Header.
> +
> +  @return Pointer to the end of the variable storage area.
> +
> +**/
> +VARIABLE_HEADER *
> +GetEndPointer (
> +  IN VARIABLE_STORE_HEADER  *VarStoreHeader
> +  )
> +{
> +  //
> +  // The end of variable store
> +  //
> +  return (VARIABLE_HEADER *)HEADER_ALIGN ((UINTN)VarStoreHeader +
> VarStoreHeader->Size);
> +}
> +
> +/**
> +  Compare two EFI_TIME data.
> +
> +
> +  @param[in] FirstTime       A pointer to the first EFI_TIME data.
> +  @param[in] SecondTime      A pointer to the second EFI_TIME data.
> +
> +  @retval  TRUE              The FirstTime is not later than the SecondTime.
> +  @retval  FALSE             The FirstTime is later than the SecondTime.
> +
> +**/
> +BOOLEAN
> +VariableCompareTimeStampInternal (
> +  IN EFI_TIME  *FirstTime,
> +  IN EFI_TIME  *SecondTime
> +  )
> +{
> +  if (FirstTime->Year != SecondTime->Year) {
> +    return (BOOLEAN)(FirstTime->Year < SecondTime->Year);
> +  } else if (FirstTime->Month != SecondTime->Month) {
> +    return (BOOLEAN)(FirstTime->Month < SecondTime->Month);
> +  } else if (FirstTime->Day != SecondTime->Day) {
> +    return (BOOLEAN)(FirstTime->Day < SecondTime->Day);
> +  } else if (FirstTime->Hour != SecondTime->Hour) {
> +    return (BOOLEAN)(FirstTime->Hour < SecondTime->Hour);
> +  } else if (FirstTime->Minute != SecondTime->Minute) {
> +    return (BOOLEAN)(FirstTime->Minute < SecondTime->Minute);
> +  }
> +
> +  return (BOOLEAN)(FirstTime->Second <= SecondTime->Second);
> +}
> +
> +/**
> +  Find the variable in the specified variable store.
> +
> +  @param[in]       VariableName        Name of the variable to be found
> +  @param[in]       VendorGuid          Vendor GUID to be found.
> +  @param[in]       IgnoreRtCheck       Ignore EFI_VARIABLE_RUNTIME_ACCESS
> attribute
> +                                       check at runtime when searching variable.
> +  @param[in, out]  PtrTrack            Variable Track Pointer structure that contains
> Variable Information.
> +  @param[in]       AuthFormat          TRUE indicates authenticated variables are
> used.
> +                                       FALSE indicates authenticated variables are not used.
> +
> +  @retval          EFI_SUCCESS         Variable found successfully
> +  @retval          EFI_NOT_FOUND       Variable not found
> +**/
> +EFI_STATUS
> +FindVariableEx (
> +  IN     CHAR16                  *VariableName,
> +  IN     EFI_GUID                *VendorGuid,
> +  IN     BOOLEAN                 IgnoreRtCheck,
> +  IN OUT VARIABLE_POINTER_TRACK  *PtrTrack,
> +  IN     BOOLEAN                 AuthFormat
> +  )
> +{
> +  VARIABLE_HEADER  *InDeletedVariable;
> +  VOID             *Point;
> +
> +  PtrTrack->InDeletedTransitionPtr = NULL;
> +
> +  //
> +  // Find the variable by walk through HOB, volatile and non-volatile variable
> store.
> +  //
> +  InDeletedVariable = NULL;
> +
> +  for ( PtrTrack->CurrPtr = PtrTrack->StartPtr
> +        ; IsValidVariableHeader (PtrTrack->CurrPtr, PtrTrack->EndPtr, AuthFormat)
> +        ; PtrTrack->CurrPtr = GetNextVariablePtr (PtrTrack->CurrPtr, AuthFormat)
> +        )
> +  {
> +    if ((PtrTrack->CurrPtr->State == VAR_ADDED) ||
> +        (PtrTrack->CurrPtr->State == (VAR_IN_DELETED_TRANSITION &
> VAR_ADDED))
> +        )
> +    {
> +      if (IgnoreRtCheck || !AtRuntime () || ((PtrTrack->CurrPtr->Attributes &
> EFI_VARIABLE_RUNTIME_ACCESS) != 0)) {
> +        if (VariableName[0] == 0) {
> +          if (PtrTrack->CurrPtr->State == (VAR_IN_DELETED_TRANSITION &
> VAR_ADDED)) {
> +            InDeletedVariable = PtrTrack->CurrPtr;
> +          } else {
> +            PtrTrack->InDeletedTransitionPtr = InDeletedVariable;
> +            return EFI_SUCCESS;
> +          }
> +        } else {
> +          if (CompareGuid (VendorGuid, GetVendorGuidPtr (PtrTrack->CurrPtr,
> AuthFormat))) {
> +            Point = (VOID *)GetVariableNamePtr (PtrTrack->CurrPtr, AuthFormat);
> +
> +            ASSERT (NameSizeOfVariable (PtrTrack->CurrPtr, AuthFormat) != 0);
> +            if (CompareMem (VariableName, Point, NameSizeOfVariable (PtrTrack-
> >CurrPtr, AuthFormat)) == 0) {
> +              if (PtrTrack->CurrPtr->State == (VAR_IN_DELETED_TRANSITION &
> VAR_ADDED)) {
> +                InDeletedVariable = PtrTrack->CurrPtr;
> +              } else {
> +                PtrTrack->InDeletedTransitionPtr = InDeletedVariable;
> +                return EFI_SUCCESS;
> +              }
> +            }
> +          }
> +        }
> +      }
> +    }
> +  }
> +
> +  PtrTrack->CurrPtr = InDeletedVariable;
> +  return (PtrTrack->CurrPtr  == NULL) ? EFI_NOT_FOUND : EFI_SUCCESS;
> +}
> +
> +/**
> +  This code finds the next available variable.
> +
> +  Caution: This function may receive untrusted input.
> +  This function may be invoked in SMM mode. This function will do basic
> validation, before parse the data.
> +
> +  @param[in]  VariableName      Pointer to variable name.
> +  @param[in]  VendorGuid        Variable Vendor Guid.
> +  @param[in]  VariableStoreList A list of variable stores that should be used to
> get the next variable.
> +                                The maximum number of entries is the max value of
> VARIABLE_STORE_TYPE.
> +  @param[out] VariablePtr       Pointer to variable header address.
> +  @param[in]  AuthFormat        TRUE indicates authenticated variables are used.
> +                                FALSE indicates authenticated variables are not used.
> +
> +  @retval EFI_SUCCESS           The function completed successfully.
> +  @retval EFI_NOT_FOUND         The next variable was not found.
> +  @retval EFI_INVALID_PARAMETER If VariableName is not an empty string,
> while VendorGuid is NULL.
> +  @retval EFI_INVALID_PARAMETER The input values of VariableName and
> VendorGuid are not a name and
> +                                GUID of an existing variable.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableServiceGetNextVariableInternal (
> +  IN  CHAR16                 *VariableName,
> +  IN  EFI_GUID               *VendorGuid,
> +  IN  VARIABLE_STORE_HEADER  **VariableStoreList,
> +  OUT VARIABLE_HEADER        **VariablePtr,
> +  IN  BOOLEAN                AuthFormat
> +  )
> +{
> +  EFI_STATUS              Status;
> +  VARIABLE_STORE_TYPE     StoreType;
> +  VARIABLE_POINTER_TRACK  Variable;
> +  VARIABLE_POINTER_TRACK  VariableInHob;
> +  VARIABLE_POINTER_TRACK  VariablePtrTrack;
> +
> +  Status = EFI_NOT_FOUND;
> +
> +  if (VariableStoreList == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  ZeroMem (&Variable, sizeof (Variable));
> +
> +  // Check if the variable exists in the given variable store list
> +  for (StoreType = (VARIABLE_STORE_TYPE)0; StoreType <
> VariableStoreTypeMax; StoreType++) {
> +    if (VariableStoreList[StoreType] == NULL) {
> +      continue;
> +    }
> +
> +    Variable.StartPtr = GetStartPointer (VariableStoreList[StoreType]);
> +    Variable.EndPtr   = GetEndPointer (VariableStoreList[StoreType]);
> +    Variable.Volatile = (BOOLEAN)(StoreType == VariableStoreTypeVolatile);
> +
> +    Status = FindVariableEx (VariableName, VendorGuid, FALSE, &Variable,
> AuthFormat);
> +    if (!EFI_ERROR (Status)) {
> +      break;
> +    }
> +  }
> +
> +  if ((Variable.CurrPtr == NULL) || EFI_ERROR (Status)) {
> +    //
> +    // For VariableName is an empty string, FindVariableEx() will try to find and
> return
> +    // the first qualified variable, and if FindVariableEx() returns error
> (EFI_NOT_FOUND)
> +    // as no any variable is found, still go to return the error (EFI_NOT_FOUND).
> +    //
> +    if (VariableName[0] != 0) {
> +      //
> +      // For VariableName is not an empty string, and FindVariableEx() returns
> error as
> +      // VariableName and VendorGuid are not a name and GUID of an existing
> variable,
> +      // there is no way to get next variable, follow spec to return
> EFI_INVALID_PARAMETER.
> +      //
> +      Status = EFI_INVALID_PARAMETER;
> +    }
> +
> +    goto Done;
> +  }
> +
> +  if (VariableName[0] != 0) {
> +    //
> +    // If variable name is not empty, get next variable.
> +    //
> +    Variable.CurrPtr = GetNextVariablePtr (Variable.CurrPtr, AuthFormat);
> +  }
> +
> +  while (TRUE) {
> +    //
> +    // Switch to the next variable store if needed
> +    //
> +    while (!IsValidVariableHeader (Variable.CurrPtr, Variable.EndPtr,
> AuthFormat)) {
> +      //
> +      // Find current storage index
> +      //
> +      for (StoreType = (VARIABLE_STORE_TYPE)0; StoreType <
> VariableStoreTypeMax; StoreType++) {
> +        if ((VariableStoreList[StoreType] != NULL) && (Variable.StartPtr ==
> GetStartPointer (VariableStoreList[StoreType]))) {
> +          break;
> +        }
> +      }
> +
> +      ASSERT (StoreType < VariableStoreTypeMax);
> +      //
> +      // Switch to next storage
> +      //
> +      for (StoreType++; StoreType < VariableStoreTypeMax; StoreType++) {
> +        if (VariableStoreList[StoreType] != NULL) {
> +          break;
> +        }
> +      }
> +
> +      //
> +      // Capture the case that
> +      // 1. current storage is the last one, or
> +      // 2. no further storage
> +      //
> +      if (StoreType == VariableStoreTypeMax) {
> +        Status = EFI_NOT_FOUND;
> +        goto Done;
> +      }
> +
> +      Variable.StartPtr = GetStartPointer (VariableStoreList[StoreType]);
> +      Variable.EndPtr   = GetEndPointer (VariableStoreList[StoreType]);
> +      Variable.CurrPtr  = Variable.StartPtr;
> +    }
> +
> +    //
> +    // Variable is found
> +    //
> +    if ((Variable.CurrPtr->State == VAR_ADDED) || (Variable.CurrPtr->State ==
> (VAR_IN_DELETED_TRANSITION & VAR_ADDED))) {
> +      if (!AtRuntime () || ((Variable.CurrPtr->Attributes &
> EFI_VARIABLE_RUNTIME_ACCESS) != 0)) {
> +        if (Variable.CurrPtr->State == (VAR_IN_DELETED_TRANSITION &
> VAR_ADDED)) {
> +          //
> +          // If it is a IN_DELETED_TRANSITION variable,
> +          // and there is also a same ADDED one at the same time,
> +          // don't return it.
> +          //
> +          VariablePtrTrack.StartPtr = Variable.StartPtr;
> +          VariablePtrTrack.EndPtr   = Variable.EndPtr;
> +          Status                    = FindVariableEx (
> +                                        GetVariableNamePtr (Variable.CurrPtr, AuthFormat),
> +                                        GetVendorGuidPtr (Variable.CurrPtr, AuthFormat),
> +                                        FALSE,
> +                                        &VariablePtrTrack,
> +                                        AuthFormat
> +                                        );
> +          if (!EFI_ERROR (Status) && (VariablePtrTrack.CurrPtr->State ==
> VAR_ADDED)) {
> +            Variable.CurrPtr = GetNextVariablePtr (Variable.CurrPtr, AuthFormat);
> +            continue;
> +          }
> +        }
> +
> +        //
> +        // Don't return NV variable when HOB overrides it
> +        //
> +        if ((VariableStoreList[VariableStoreTypeHob] != NULL) &&
> (VariableStoreList[VariableStoreTypeNv] != NULL) &&
> +            (Variable.StartPtr == GetStartPointer
> (VariableStoreList[VariableStoreTypeNv]))
> +            )
> +        {
> +          VariableInHob.StartPtr = GetStartPointer
> (VariableStoreList[VariableStoreTypeHob]);
> +          VariableInHob.EndPtr   = GetEndPointer
> (VariableStoreList[VariableStoreTypeHob]);
> +          Status                 = FindVariableEx (
> +                                     GetVariableNamePtr (Variable.CurrPtr, AuthFormat),
> +                                     GetVendorGuidPtr (Variable.CurrPtr, AuthFormat),
> +                                     FALSE,
> +                                     &VariableInHob,
> +                                     AuthFormat
> +                                     );
> +          if (!EFI_ERROR (Status)) {
> +            Variable.CurrPtr = GetNextVariablePtr (Variable.CurrPtr, AuthFormat);
> +            continue;
> +          }
> +        }
> +
> +        *VariablePtr = Variable.CurrPtr;
> +        Status       = EFI_SUCCESS;
> +        goto Done;
> +      }
> +    }
> +
> +    Variable.CurrPtr = GetNextVariablePtr (Variable.CurrPtr, AuthFormat);
> +  }
> +
> +Done:
> +  return Status;
> +}
> +
> +/**
> +  Routine used to track statistical information about variable usage.
> +  The data is stored in the EFI system table so it can be accessed later.
> +  VariableInfo.efi can dump out the table. Only Boot Services variable
> +  accesses are tracked by this code. The PcdVariableCollectStatistics
> +  build flag controls if this feature is enabled.
> +
> +  A read that hits in the cache will have Read and Cache true for
> +  the transaction. Data is allocated by this routine, but never
> +  freed.
> +
> +  @param[in]      VariableName   Name of the Variable to track.
> +  @param[in]      VendorGuid     Guid of the Variable to track.
> +  @param[in]      Volatile       TRUE if volatile FALSE if non-volatile.
> +  @param[in]      Read           TRUE if GetVariable() was called.
> +  @param[in]      Write          TRUE if SetVariable() was called.
> +  @param[in]      Delete         TRUE if deleted via SetVariable().
> +  @param[in]      Cache          TRUE for a cache hit.
> +  @param[in,out]  VariableInfo   Pointer to a pointer of VARIABLE_INFO_ENTRY
> structures.
> +
> +**/
> +VOID
> +UpdateVariableInfo (
> +  IN  CHAR16                  *VariableName,
> +  IN  EFI_GUID                *VendorGuid,
> +  IN  BOOLEAN                 Volatile,
> +  IN  BOOLEAN                 Read,
> +  IN  BOOLEAN                 Write,
> +  IN  BOOLEAN                 Delete,
> +  IN  BOOLEAN                 Cache,
> +  IN OUT VARIABLE_INFO_ENTRY  **VariableInfo
> +  )
> +{
> +  VARIABLE_INFO_ENTRY  *Entry;
> +
> +  if (FeaturePcdGet (PcdVariableCollectStatistics)) {
> +    if ((VariableName == NULL) || (VendorGuid == NULL) || (VariableInfo ==
> NULL)) {
> +      return;
> +    }
> +
> +    if (AtRuntime ()) {
> +      // Don't collect statistics at runtime.
> +      return;
> +    }
> +
> +    if (*VariableInfo == NULL) {
> +      //
> +      // On the first call allocate a entry and place a pointer to it in
> +      // the EFI System Table.
> +      //
> +      *VariableInfo = AllocateZeroPool (sizeof (VARIABLE_INFO_ENTRY));
> +      ASSERT (*VariableInfo != NULL);
> +
> +      CopyGuid (&(*VariableInfo)->VendorGuid, VendorGuid);
> +      (*VariableInfo)->Name = AllocateZeroPool (StrSize (VariableName));
> +      ASSERT ((*VariableInfo)->Name != NULL);
> +      StrCpyS ((*VariableInfo)->Name, StrSize (VariableName)/sizeof (CHAR16),
> VariableName);
> +      (*VariableInfo)->Volatile = Volatile;
> +    }
> +
> +    for (Entry = (*VariableInfo); Entry != NULL; Entry = Entry->Next) {
> +      if (CompareGuid (VendorGuid, &Entry->VendorGuid)) {
> +        if (StrCmp (VariableName, Entry->Name) == 0) {
> +          if (Read) {
> +            Entry->ReadCount++;
> +          }
> +
> +          if (Write) {
> +            Entry->WriteCount++;
> +          }
> +
> +          if (Delete) {
> +            Entry->DeleteCount++;
> +          }
> +
> +          if (Cache) {
> +            Entry->CacheCount++;
> +          }
> +
> +          return;
> +        }
> +      }
> +
> +      if (Entry->Next == NULL) {
> +        //
> +        // If the entry is not in the table add it.
> +        // Next iteration of the loop will fill in the data.
> +        //
> +        Entry->Next = AllocateZeroPool (sizeof (VARIABLE_INFO_ENTRY));
> +        ASSERT (Entry->Next != NULL);
> +
> +        CopyGuid (&Entry->Next->VendorGuid, VendorGuid);
> +        Entry->Next->Name = AllocateZeroPool (StrSize (VariableName));
> +        ASSERT (Entry->Next->Name != NULL);
> +        StrCpyS (Entry->Next->Name, StrSize (VariableName)/sizeof (CHAR16),
> VariableName);
> +        Entry->Next->Volatile = Volatile;
> +      }
> +    }
> +  }
> +}
> +
> +/**
> +
> +  Retrieve details about a variable and return them in VariableInfo->Header.
> +
> +  If VariableInfo->Buffer is given, this function will calculate its offset
> +  relative to given variable storage via VariableStore; Otherwise, it will try
> +  other internal variable storages or cached copies. It's assumed that, for all
> +  copies of NV variable storage, all variables are stored in the same relative
> +  position. If VariableInfo->Buffer is found in the range of any storage copies,
> +  its offset relative to that storage should be the same in other copies.
> +
> +  If VariableInfo->Offset is given (non-zero) but not VariableInfo->Buffer,
> +  this function will return the variable memory address inside VariableStore,
> +  if given, via VariableInfo->Address; Otherwise, the address of other storage
> +  copies will be returned, if any.
> +
> +  For a new variable whose offset has not been determined, a value of -1 as
> +  VariableInfo->Offset should be passed to skip the offset calculation.
> +
> +  @param[in,out] VariableInfo             Pointer to variable information.
> +
> +  @retval EFI_INVALID_PARAMETER  VariableInfo is NULL or both VariableInfo-
> >Address
> +                                 and VariableInfo->Offset are NULL (0).
> +  @retval EFI_NOT_FOUND          If given Address or Offset is out of range of
> +                                 any given or internal storage copies.
> +  @retval EFI_SUCCESS            Variable details are retrieved successfully.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +GetVariableInfo (
> +  IN OUT  PROTECTED_VARIABLE_INFO  *VariableInfo
> +  )
> +{
> +  VARIABLE_STORE_HEADER          *Stores[2];
> +  UINTN                          Index;
> +  VARIABLE_HEADER                *VariablePtr;
> +  VARIABLE_HEADER                *VariableBuffer;
> +  AUTHENTICATED_VARIABLE_HEADER  *AuthVariablePtr;
> +  BOOLEAN                        AuthFlag;
> +  UINTN                          NameSize;
> +  UINTN                          DataSize;
> +  UINTN                          VariableSize;
> +
> +  if ((VariableInfo == NULL) || (  (VariableInfo->Buffer == NULL)
> +                                && (VariableInfo->StoreIndex == VAR_INDEX_INVALID)))
> +  {
> +    ASSERT (VariableInfo != NULL);
> +    ASSERT (VariableInfo->Buffer != NULL || VariableInfo->StoreIndex !=
> VAR_INDEX_INVALID);
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  Stores[0] = mNvVariableCache;
> +  Stores[1] = (mVariableModuleGlobal != NULL)
> +              ? (VARIABLE_STORE_HEADER *)(UINTN)mVariableModuleGlobal-
> >VariableGlobal.NonVolatileVariableBase
> +              : NULL;
> +
> +  VariableBuffer = VariableInfo->Buffer;
> +  VariablePtr    = NULL;
> +  if (VariableInfo->StoreIndex != VAR_INDEX_INVALID) {
> +    for (Index = 0; Index < ARRAY_SIZE (Stores); ++Index) {
> +      if (Stores[Index] == NULL) {
> +        continue;
> +      }
> +
> +      if ((UINTN)VariableInfo->StoreIndex
> +          < ((UINTN)GetEndPointer (Stores[Index]) - (UINTN)Stores[Index]))
> +      {
> +        VariablePtr          = (VARIABLE_HEADER *)((UINTN)Stores[Index] +
> (UINTN)VariableInfo->StoreIndex);
> +        VariableInfo->Buffer = VariablePtr;
> +        break;
> +      }
> +    }
> +  } else {
> +    VariablePtr = VariableInfo->Buffer;
> +  }
> +
> +  if (VariablePtr == NULL) {
> +    return EFI_NOT_FOUND;
> +  }
> +
> +  AuthFlag = VariableInfo->Flags.Auth;
> +  ASSERT (AuthFlag == TRUE || AuthFlag == FALSE);
> +
> +  //
> +  // Make a copy of the whole variable if a buffer is passed in.
> +  //
> +  if ((VariableBuffer != NULL) && (VariableBuffer != VariablePtr)) {
> +    VariableSize = (UINTN)GetNextVariablePtr (VariablePtr, AuthFlag)
> +                   - (UINTN)VariablePtr;
> +    CopyMem (VariableBuffer, VariablePtr, VariableSize);
> +  }
> +
> +  //
> +  // AuthVariable header
> +  //
> +  if (AuthFlag) {
> +    AuthVariablePtr = (AUTHENTICATED_VARIABLE_HEADER *)VariablePtr;
> +
> +    VariableInfo->Header.State          = AuthVariablePtr->State;
> +    VariableInfo->Header.Attributes     = AuthVariablePtr->Attributes;
> +    VariableInfo->Header.PubKeyIndex    = AuthVariablePtr->PubKeyIndex;
> +    VariableInfo->Header.MonotonicCount = ReadUnaligned64 (
> +                                            &(AuthVariablePtr->MonotonicCount)
> +                                            );
> +    if (VariableInfo->Header.TimeStamp != NULL) {
> +      CopyMem (
> +        VariableInfo->Header.TimeStamp,
> +        &AuthVariablePtr->TimeStamp,
> +        sizeof (EFI_TIME)
> +        );
> +    } else if (VariableBuffer != NULL) {
> +      AuthVariablePtr                = (AUTHENTICATED_VARIABLE_HEADER
> *)VariableBuffer;
> +      VariableInfo->Header.TimeStamp = &AuthVariablePtr->TimeStamp;
> +    }
> +  } else {
> +    VariableInfo->Header.State          = VariablePtr->State;
> +    VariableInfo->Header.Attributes     = VariablePtr->Attributes;
> +    VariableInfo->Header.PubKeyIndex    = 0;
> +    VariableInfo->Header.MonotonicCount = 0;
> +    VariableInfo->Header.TimeStamp      = NULL;
> +  }
> +
> +  //
> +  // VendorGuid
> +  //
> +  if (VariableInfo->Header.VendorGuid != NULL) {
> +    CopyGuid (
> +      VariableInfo->Header.VendorGuid,
> +      GetVendorGuidPtr (VariablePtr, AuthFlag)
> +      );
> +  } else {
> +    VariableInfo->Header.VendorGuid = GetVendorGuidPtr (VariablePtr,
> AuthFlag);
> +  }
> +
> +  //
> +  // VariableName
> +  //
> +  NameSize = NameSizeOfVariable (VariablePtr, AuthFlag);
> +  if (  (VariableInfo->Header.VariableName != NULL)
> +     && (VariableInfo->Header.NameSize >= NameSize))
> +  {
> +    CopyMem (
> +      VariableInfo->Header.VariableName,
> +      GetVariableNamePtr (VariablePtr, AuthFlag),
> +      NameSize
> +      );
> +  } else if (VariableInfo->Header.VariableName != NULL) {
> +    return EFI_BUFFER_TOO_SMALL;
> +  } else {
> +    VariableInfo->Header.VariableName = GetVariableNamePtr (VariablePtr,
> AuthFlag);
> +  }
> +
> +  //
> +  // Data
> +  //
> +  DataSize = DataSizeOfVariable (VariablePtr, AuthFlag);
> +  if (  (VariableInfo->Header.Data != NULL)
> +     && (VariableInfo->Header.DataSize >= DataSize))
> +  {
> +    CopyMem (
> +      VariableInfo->Header.Data,
> +      GetVariableDataPtr (VariablePtr, AuthFlag),
> +      NameSize
> +      );
> +  } else if (VariableInfo->Header.Data != NULL) {
> +    return EFI_BUFFER_TOO_SMALL;
> +  } else {
> +    VariableInfo->Header.Data = GetVariableDataPtr (VariablePtr, AuthFlag);
> +  }
> +
> +  //
> +  // Update size information about name & data.
> +  //
> +  VariableInfo->Header.NameSize = NameSize;
> +  VariableInfo->Header.DataSize = DataSize;
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +
> +  Retrieve details of the variable next to given variable within VariableStore.
> +
> +  If VariableInfo->StoreIndex is invalid, the first one in VariableStore is returned.
> +
> +  @param[in,out] VariableInfo             Pointer to variable information.
> +
> +  @retval EFI_INVALID_PARAMETER  VariableInfo or VariableStore is NULL.
> +  @retval EFI_NOT_FOUND          If the end of VariableStore is reached.
> +  @retval EFI_SUCCESS            The next variable is retrieved successfully.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +GetNextVariableInfo (
> +  IN OUT  PROTECTED_VARIABLE_INFO  *VariableInfo
> +  )
> +{
> +  VARIABLE_STORE_HEADER  *VarStore;
> +  VARIABLE_HEADER        *VariablePtr;
> +  VARIABLE_HEADER        *VariableStart;
> +  VARIABLE_HEADER        *VariableEnd;
> +  BOOLEAN                AuthFlag;
> +
> +  if (VariableInfo == NULL) {
> +    ASSERT (VariableInfo != NULL);
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (mNvVariableCache != NULL) {
> +    VarStore = mNvVariableCache;
> +  } else if (mVariableModuleGlobal != NULL) {
> +    VarStore = (VARIABLE_STORE_HEADER *)(UINTN)
> +               mVariableModuleGlobal->VariableGlobal.NonVolatileVariableBase;
> +  } else {
> +    return EFI_NOT_FOUND;
> +  }
> +
> +  VariableStart = GetStartPointer (VarStore);
> +  VariableEnd   = GetEndPointer (VarStore);
> +
> +  if ((VariableInfo->Flags.Auth != TRUE) && (VariableInfo->Flags.Auth != FALSE))
> {
> +    VariableInfo->Flags.Auth = CompareGuid (
> +                                 &VarStore->Signature,
> +                                 &gEfiAuthenticatedVariableGuid
> +                                 );
> +  }
> +
> +  AuthFlag = VariableInfo->Flags.Auth;
> +
> +  if (VariableInfo->StoreIndex == VAR_INDEX_INVALID) {
> +    VariablePtr = VariableStart;
> +  } else {
> +    VariablePtr = (VARIABLE_HEADER *)
> +                  ((UINTN)VarStore + (UINTN)VariableInfo->StoreIndex);
> +    if (VariablePtr >= VariableEnd) {
> +      return EFI_NOT_FOUND;
> +    }
> +
> +    VariablePtr = GetNextVariablePtr (VariablePtr, AuthFlag);
> +  }
> +
> +  if (!IsValidVariableHeader (VariablePtr, VariableEnd, AuthFlag)) {
> +    return EFI_NOT_FOUND;
> +  }
> +
> +  VariableInfo->StoreIndex = (UINTN)VariablePtr - (UINTN)VarStore;
> +  return GetVariableInfo (VariableInfo);
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariablePolicySm
> mDxe.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariablePolicySm
> mDxe.c
> new file mode 100644
> index 000000000000..b2094fbcd6ea
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariablePolicySm
> mDxe.c
> @@ -0,0 +1,575 @@
> +/** @file -- VariablePolicySmmDxe.c
> +This protocol allows communication with Variable Policy Engine.
> +
> +Copyright (c) Microsoft Corporation.
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <Library/BaseLib.h>
> +#include <Library/UefiLib.h>
> +#include <Library/DebugLib.h>
> +#include <Library/SafeIntLib.h>
> +#include <Library/UefiBootServicesTableLib.h>
> +#include <Library/BaseMemoryLib.h>
> +#include <Library/MemoryAllocationLib.h>
> +
> +#include <Protocol/VariablePolicy.h>
> +#include <Protocol/MmCommunication2.h>
> +
> +#include <Guid/VarCheckPolicyMmi.h>
> +
> +#include "Variable.h"
> +
> +EDKII_VARIABLE_POLICY_PROTOCOL  mVariablePolicyProtocol;
> +EFI_MM_COMMUNICATION2_PROTOCOL  *mMmCommunication;
> +
> +VOID      *mMmCommunicationBuffer;
> +UINTN     mMmCommunicationBufferSize;
> +EFI_LOCK  mMmCommunicationLock;
> +
> +/**
> +  Internal helper function to consolidate communication method.
> +
> +  @param[in,out]  CommBuffer
> +  @param[in,out]  CommSize    Size of the CommBuffer.
> +
> +  @retval   EFI_STATUS    Result from communication method.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +InternalMmCommunicate (
> +  IN OUT VOID   *CommBuffer,
> +  IN OUT UINTN  *CommSize
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  if ((CommBuffer == NULL) || (CommSize == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  Status = mMmCommunication->Communicate (mMmCommunication,
> CommBuffer, CommBuffer, CommSize);
> +  return Status;
> +}
> +
> +/**
> +  This API function disables the variable policy enforcement. If it's
> +  already been called once, will return EFI_ALREADY_STARTED.
> +
> +  @retval     EFI_SUCCESS
> +  @retval     EFI_ALREADY_STARTED   Has already been called once this boot.
> +  @retval     EFI_WRITE_PROTECTED   Interface has been locked until reboot.
> +  @retval     EFI_WRITE_PROTECTED   Interface option is disabled by platform
> PCD.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +ProtocolDisableVariablePolicy (
> +  VOID
> +  )
> +{
> +  EFI_STATUS                    Status;
> +  EFI_MM_COMMUNICATE_HEADER     *CommHeader;
> +  VAR_CHECK_POLICY_COMM_HEADER  *PolicyHeader;
> +  UINTN                         BufferSize;
> +
> +  // Check the PCD for convenience.
> +  // This would also be rejected by the lib, but why go to MM if we don't have to?
> +  if (!PcdGetBool (PcdAllowVariablePolicyEnforcementDisable)) {
> +    return EFI_WRITE_PROTECTED;
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mMmCommunicationLock);
> +
> +  // Set up the MM communication.
> +  BufferSize   = mMmCommunicationBufferSize;
> +  CommHeader   = mMmCommunicationBuffer;
> +  PolicyHeader = (VAR_CHECK_POLICY_COMM_HEADER *)&CommHeader-
> >Data;
> +  CopyGuid (&CommHeader->HeaderGuid,
> &gVarCheckPolicyLibMmiHandlerGuid);
> +  CommHeader->MessageLength = BufferSize - OFFSET_OF
> (EFI_MM_COMMUNICATE_HEADER, Data);
> +  PolicyHeader->Signature   = VAR_CHECK_POLICY_COMM_SIG;
> +  PolicyHeader->Revision    = VAR_CHECK_POLICY_COMM_REVISION;
> +  PolicyHeader->Command     = VAR_CHECK_POLICY_COMMAND_DISABLE;
> +
> +  Status = InternalMmCommunicate (CommHeader, &BufferSize);
> +  DEBUG ((DEBUG_VERBOSE, "%a - MmCommunication returned %r.\n",
> __FUNCTION__, Status));
> +
> +  ReleaseLockOnlyAtBootTime (&mMmCommunicationLock);
> +
> +  return (EFI_ERROR (Status)) ? Status : PolicyHeader->Result;
> +}
> +
> +/**
> +  This API function returns whether or not the policy engine is
> +  currently being enforced.
> +
> +  @param[out]   State       Pointer to a return value for whether the policy
> enforcement
> +                            is currently enabled.
> +
> +  @retval     EFI_SUCCESS
> +  @retval     Others        An error has prevented this command from completing.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +ProtocolIsVariablePolicyEnabled (
> +  OUT BOOLEAN  *State
> +  )
> +{
> +  EFI_STATUS                               Status;
> +  EFI_MM_COMMUNICATE_HEADER                *CommHeader;
> +  VAR_CHECK_POLICY_COMM_HEADER             *PolicyHeader;
> +  VAR_CHECK_POLICY_COMM_IS_ENABLED_PARAMS  *CommandParams;
> +  UINTN                                    BufferSize;
> +
> +  if (State == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mMmCommunicationLock);
> +
> +  // Set up the MM communication.
> +  BufferSize    = mMmCommunicationBufferSize;
> +  CommHeader    = mMmCommunicationBuffer;
> +  PolicyHeader  = (VAR_CHECK_POLICY_COMM_HEADER *)&CommHeader-
> >Data;
> +  CommandParams = (VAR_CHECK_POLICY_COMM_IS_ENABLED_PARAMS
> *)(PolicyHeader + 1);
> +  CopyGuid (&CommHeader->HeaderGuid,
> &gVarCheckPolicyLibMmiHandlerGuid);
> +  CommHeader->MessageLength = BufferSize - OFFSET_OF
> (EFI_MM_COMMUNICATE_HEADER, Data);
> +  PolicyHeader->Signature   = VAR_CHECK_POLICY_COMM_SIG;
> +  PolicyHeader->Revision    = VAR_CHECK_POLICY_COMM_REVISION;
> +  PolicyHeader->Command     = VAR_CHECK_POLICY_COMMAND_IS_ENABLED;
> +
> +  Status = InternalMmCommunicate (CommHeader, &BufferSize);
> +  DEBUG ((DEBUG_VERBOSE, "%a - MmCommunication returned %r.\n",
> __FUNCTION__, Status));
> +
> +  if (!EFI_ERROR (Status)) {
> +    Status = PolicyHeader->Result;
> +    *State = CommandParams->State;
> +  }
> +
> +  ReleaseLockOnlyAtBootTime (&mMmCommunicationLock);
> +
> +  return Status;
> +}
> +
> +/**
> +  This API function validates and registers a new policy with
> +  the policy enforcement engine.
> +
> +  @param[in]  NewPolicy     Pointer to the incoming policy structure.
> +
> +  @retval     EFI_SUCCESS
> +  @retval     EFI_INVALID_PARAMETER   NewPolicy is NULL or is internally
> inconsistent.
> +  @retval     EFI_ALREADY_STARTED     An identical matching policy already
> exists.
> +  @retval     EFI_WRITE_PROTECTED     The interface has been locked until the
> next reboot.
> +  @retval     EFI_UNSUPPORTED         Policy enforcement has been disabled. No
> reason to add more policies.
> +  @retval     EFI_ABORTED             A calculation error has prevented this function
> from completing.
> +  @retval     EFI_OUT_OF_RESOURCES    Cannot grow the table to hold any
> more policies.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +ProtocolRegisterVariablePolicy (
> +  IN CONST VARIABLE_POLICY_ENTRY  *NewPolicy
> +  )
> +{
> +  EFI_STATUS                    Status;
> +  EFI_MM_COMMUNICATE_HEADER     *CommHeader;
> +  VAR_CHECK_POLICY_COMM_HEADER  *PolicyHeader;
> +  VOID                          *PolicyBuffer;
> +  UINTN                         BufferSize;
> +  UINTN                         RequiredSize;
> +
> +  if (NewPolicy == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  // First, make sure that the required size does not exceed the capabilities
> +  // of the MmCommunication buffer.
> +  RequiredSize = OFFSET_OF (EFI_MM_COMMUNICATE_HEADER, Data) + sizeof
> (VAR_CHECK_POLICY_COMM_HEADER);
> +  Status       = SafeUintnAdd (RequiredSize, NewPolicy->Size, &RequiredSize);
> +  if (EFI_ERROR (Status) || (RequiredSize > mMmCommunicationBufferSize)) {
> +    DEBUG ((
> +      DEBUG_ERROR,
> +      "%a - Policy too large for buffer! %r, %d > %d \n",
> +      __FUNCTION__,
> +      Status,
> +      RequiredSize,
> +      mMmCommunicationBufferSize
> +      ));
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mMmCommunicationLock);
> +
> +  // Set up the MM communication.
> +  BufferSize   = mMmCommunicationBufferSize;
> +  CommHeader   = mMmCommunicationBuffer;
> +  PolicyHeader = (VAR_CHECK_POLICY_COMM_HEADER *)&CommHeader-
> >Data;
> +  PolicyBuffer = (VOID *)(PolicyHeader + 1);
> +  CopyGuid (&CommHeader->HeaderGuid,
> &gVarCheckPolicyLibMmiHandlerGuid);
> +  CommHeader->MessageLength = BufferSize - OFFSET_OF
> (EFI_MM_COMMUNICATE_HEADER, Data);
> +  PolicyHeader->Signature   = VAR_CHECK_POLICY_COMM_SIG;
> +  PolicyHeader->Revision    = VAR_CHECK_POLICY_COMM_REVISION;
> +  PolicyHeader->Command     = VAR_CHECK_POLICY_COMMAND_REGISTER;
> +
> +  // Copy the policy into place. This copy is safe because we've already tested
> above.
> +  CopyMem (PolicyBuffer, NewPolicy, NewPolicy->Size);
> +
> +  Status = InternalMmCommunicate (CommHeader, &BufferSize);
> +  DEBUG ((DEBUG_VERBOSE, "%a - MmCommunication returned %r.\n",
> __FUNCTION__, Status));
> +
> +  ReleaseLockOnlyAtBootTime (&mMmCommunicationLock);
> +
> +  return (EFI_ERROR (Status)) ? Status : PolicyHeader->Result;
> +}
> +
> +/**
> +  This helper function takes care of the overhead of formatting, sending, and
> interpreting
> +  the results for a single DumpVariablePolicy request.
> +
> +  @param[in]      PageRequested   The page of the paginated results from MM.
> 0 for metadata.
> +  @param[out]     TotalSize       The total size of the entire buffer. Returned as
> part of metadata.
> +  @param[out]     PageSize        The size of the current page being returned. Not
> valid as part of metadata.
> +  @param[out]     HasMore         A flag indicating whether there are more pages
> after this one.
> +  @param[out]     Buffer          The start of the current page from MM.
> +
> +  @retval     EFI_SUCCESS             Output params have been updated (either
> metadata or dump page).
> +  @retval     EFI_INVALID_PARAMETER   One of the output params is NULL.
> +  @retval     Others                  Response from MM handler.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +DumpVariablePolicyHelper (
> +  IN  UINT32   PageRequested,
> +  OUT UINT32   *TotalSize,
> +  OUT UINT32   *PageSize,
> +  OUT BOOLEAN  *HasMore,
> +  OUT UINT8    **Buffer
> +  )
> +{
> +  EFI_STATUS                         Status;
> +  EFI_MM_COMMUNICATE_HEADER          *CommHeader;
> +  VAR_CHECK_POLICY_COMM_HEADER       *PolicyHeader;
> +  VAR_CHECK_POLICY_COMM_DUMP_PARAMS  *CommandParams;
> +  UINTN                              BufferSize;
> +
> +  if ((TotalSize == NULL) || (PageSize == NULL) || (HasMore == NULL) || (Buffer
> == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  // Set up the MM communication.
> +  BufferSize    = mMmCommunicationBufferSize;
> +  CommHeader    = mMmCommunicationBuffer;
> +  PolicyHeader  = (VAR_CHECK_POLICY_COMM_HEADER *)&CommHeader-
> >Data;
> +  CommandParams = (VAR_CHECK_POLICY_COMM_DUMP_PARAMS
> *)(PolicyHeader + 1);
> +  CopyGuid (&CommHeader->HeaderGuid,
> &gVarCheckPolicyLibMmiHandlerGuid);
> +  CommHeader->MessageLength = BufferSize - OFFSET_OF
> (EFI_MM_COMMUNICATE_HEADER, Data);
> +  PolicyHeader->Signature   = VAR_CHECK_POLICY_COMM_SIG;
> +  PolicyHeader->Revision    = VAR_CHECK_POLICY_COMM_REVISION;
> +  PolicyHeader->Command     = VAR_CHECK_POLICY_COMMAND_DUMP;
> +
> +  CommandParams->PageRequested = PageRequested;
> +
> +  Status = InternalMmCommunicate (CommHeader, &BufferSize);
> +  DEBUG ((DEBUG_VERBOSE, "%a - MmCommunication returned %r.\n",
> __FUNCTION__, Status));
> +
> +  if (!EFI_ERROR (Status)) {
> +    Status     = PolicyHeader->Result;
> +    *TotalSize = CommandParams->TotalSize;
> +    *PageSize  = CommandParams->PageSize;
> +    *HasMore   = CommandParams->HasMore;
> +    *Buffer    = (UINT8 *)(CommandParams + 1);
> +  }
> +
> +  return Status;
> +}
> +
> +/**
> +  This API function will dump the entire contents of the variable policy table.
> +
> +  Similar to GetVariable, the first call can be made with a 0 size and it will return
> +  the size of the buffer required to hold the entire table.
> +
> +  @param[out]     Policy  Pointer to the policy buffer. Can be NULL if Size is 0.
> +  @param[in,out]  Size    On input, the size of the output buffer. On output, the
> size
> +                          of the data returned.
> +
> +  @retval     EFI_SUCCESS             Policy data is in the output buffer and Size has
> been updated.
> +  @retval     EFI_INVALID_PARAMETER   Size is NULL, or Size is non-zero and
> Policy is NULL.
> +  @retval     EFI_BUFFER_TOO_SMALL    Size is insufficient to hold policy. Size
> updated with required size.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +ProtocolDumpVariablePolicy (
> +  OUT UINT8      *Policy OPTIONAL,
> +  IN OUT UINT32  *Size
> +  )
> +{
> +  EFI_STATUS  Status;
> +  UINT8       *Source;
> +  UINT8       *Destination;
> +  UINT32      PolicySize;
> +  UINT32      PageSize;
> +  BOOLEAN     HasMore;
> +  UINT32      PageIndex;
> +
> +  if ((Size == NULL) || ((*Size > 0) && (Policy == NULL))) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mMmCommunicationLock);
> +
> +  // Repeat this whole process until we either have a failure case or get the
> entire buffer.
> +  do {
> +    // First, we must check the zero page to determine the buffer size and
> +    // reset the internal state.
> +    PolicySize = 0;
> +    PageSize   = 0;
> +    HasMore    = FALSE;
> +    Status     = DumpVariablePolicyHelper (0, &PolicySize, &PageSize, &HasMore,
> &Source);
> +    if (EFI_ERROR (Status)) {
> +      break;
> +    }
> +
> +    // If we're good, we can at least check the required size now.
> +    if (*Size < PolicySize) {
> +      *Size  = PolicySize;
> +      Status = EFI_BUFFER_TOO_SMALL;
> +      break;
> +    }
> +
> +    // On further thought, let's update the size either way.
> +    *Size = PolicySize;
> +    // And get ready to ROCK.
> +    Destination = Policy;
> +
> +    // Keep looping and copying until we're either done or freak out.
> +    for (PageIndex = 1; !EFI_ERROR (Status) && HasMore && PageIndex <
> MAX_UINT32; PageIndex++) {
> +      Status = DumpVariablePolicyHelper (PageIndex, &PolicySize, &PageSize,
> &HasMore, &Source);
> +      if (!EFI_ERROR (Status)) {
> +        CopyMem (Destination, Source, PageSize);
> +        Destination += PageSize;
> +      }
> +    }
> +
> +    // Next, we check to see whether
> +  } while (Status == EFI_TIMEOUT);
> +
> +  ReleaseLockOnlyAtBootTime (&mMmCommunicationLock);
> +
> +  // There's currently no use for this, but it shouldn't be hard to implement.
> +  return Status;
> +}
> +
> +/**
> +  This API function locks the interface so that no more policy updates
> +  can be performed or changes made to the enforcement until the next boot.
> +
> +  @retval     EFI_SUCCESS
> +  @retval     Others        An error has prevented this command from completing.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +ProtocolLockVariablePolicy (
> +  VOID
> +  )
> +{
> +  EFI_STATUS                    Status;
> +  EFI_MM_COMMUNICATE_HEADER     *CommHeader;
> +  VAR_CHECK_POLICY_COMM_HEADER  *PolicyHeader;
> +  UINTN                         BufferSize;
> +
> +  AcquireLockOnlyAtBootTime (&mMmCommunicationLock);
> +
> +  // Set up the MM communication.
> +  BufferSize   = mMmCommunicationBufferSize;
> +  CommHeader   = mMmCommunicationBuffer;
> +  PolicyHeader = (VAR_CHECK_POLICY_COMM_HEADER *)&CommHeader-
> >Data;
> +  CopyGuid (&CommHeader->HeaderGuid,
> &gVarCheckPolicyLibMmiHandlerGuid);
> +  CommHeader->MessageLength = BufferSize - OFFSET_OF
> (EFI_MM_COMMUNICATE_HEADER, Data);
> +  PolicyHeader->Signature   = VAR_CHECK_POLICY_COMM_SIG;
> +  PolicyHeader->Revision    = VAR_CHECK_POLICY_COMM_REVISION;
> +  PolicyHeader->Command     = VAR_CHECK_POLICY_COMMAND_LOCK;
> +
> +  Status = InternalMmCommunicate (CommHeader, &BufferSize);
> +  DEBUG ((DEBUG_VERBOSE, "%a - MmCommunication returned %r.\n",
> __FUNCTION__, Status));
> +
> +  ReleaseLockOnlyAtBootTime (&mMmCommunicationLock);
> +
> +  return (EFI_ERROR (Status)) ? Status : PolicyHeader->Result;
> +}
> +
> +/**
> +  This helper function locates the shared comm buffer and assigns it to input
> pointers.
> +
> +  @param[in,out]  BufferSize      On input, the minimum buffer size required
> INCLUDING the MM communicate header.
> +                                  On output, the size of the matching buffer found.
> +  @param[out]     LocatedBuffer   A pointer to the matching buffer.
> +
> +  @retval     EFI_SUCCESS
> +  @retval     EFI_INVALID_PARAMETER   One of the output pointers was NULL.
> +  @retval     EFI_OUT_OF_RESOURCES    Not enough memory to allocate a
> comm buffer.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +InitMmCommonCommBuffer (
> +  IN OUT  UINTN  *BufferSize,
> +  OUT     VOID   **LocatedBuffer
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  Status = EFI_SUCCESS;
> +
> +  // Make sure that we're working with good pointers.
> +  if ((BufferSize == NULL) || (LocatedBuffer == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  // Allocate the runtime memory for the comm buffer.
> +  *LocatedBuffer = AllocateRuntimePool (*BufferSize);
> +  if (*LocatedBuffer == NULL) {
> +    Status      = EFI_OUT_OF_RESOURCES;
> +    *BufferSize = 0;
> +  }
> +
> +  EfiInitializeLock (&mMmCommunicationLock, TPL_NOTIFY);
> +
> +  return Status;
> +}
> +
> +/**
> +  Convert internal pointer addresses to virtual addresses.
> +
> +  @param[in] Event      Event whose notification function is being invoked.
> +  @param[in] Context    The pointer to the notification function's context,
> which
> +                        is implementation-dependent.
> +**/
> +STATIC
> +VOID
> +EFIAPI
> +VariablePolicyVirtualAddressCallback (
> +  IN  EFI_EVENT  Event,
> +  IN  VOID       *Context
> +  )
> +{
> +  EfiConvertPointer (0, (VOID **)&mMmCommunication);
> +  EfiConvertPointer (0, (VOID **)&mMmCommunicationBuffer);
> +}
> +
> +/**
> +  The driver's entry point.
> +
> +  @param[in] ImageHandle  The firmware allocated handle for the EFI image.
> +  @param[in] SystemTable  A pointer to the EFI System Table.
> +
> +  @retval EFI_SUCCESS     The entry point executed successfully.
> +  @retval other           Some error occured when executing this entry point.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariablePolicySmmDxeMain (
> +  IN    EFI_HANDLE        ImageHandle,
> +  IN    EFI_SYSTEM_TABLE  *SystemTable
> +  )
> +{
> +  EFI_STATUS  Status;
> +  BOOLEAN     ProtocolInstalled;
> +  BOOLEAN     VirtualAddressChangeRegistered;
> +  EFI_EVENT   VirtualAddressChangeEvent;
> +
> +  Status                         = EFI_SUCCESS;
> +  ProtocolInstalled              = FALSE;
> +  VirtualAddressChangeRegistered = FALSE;
> +
> +  // Update the minimum buffer size.
> +  mMmCommunicationBufferSize =
> VAR_CHECK_POLICY_MM_COMM_BUFFER_SIZE;
> +  // Locate the shared comm buffer to use for sending MM commands.
> +  Status = InitMmCommonCommBuffer (&mMmCommunicationBufferSize,
> &mMmCommunicationBuffer);
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "%a - Failed to locate a viable MM comm
> buffer! %r\n", __FUNCTION__, Status));
> +    ASSERT_EFI_ERROR (Status);
> +    return Status;
> +  }
> +
> +  // Locate the MmCommunication protocol.
> +  Status = gBS->LocateProtocol (&gEfiMmCommunication2ProtocolGuid, NULL,
> (VOID **)&mMmCommunication);
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "%a - Failed to locate MmCommunication
> protocol! %r\n", __FUNCTION__, Status));
> +    ASSERT_EFI_ERROR (Status);
> +    return Status;
> +  }
> +
> +  // Configure the VariablePolicy protocol structure.
> +  mVariablePolicyProtocol.Revision                =
> EDKII_VARIABLE_POLICY_PROTOCOL_REVISION;
> +  mVariablePolicyProtocol.DisableVariablePolicy   =
> ProtocolDisableVariablePolicy;
> +  mVariablePolicyProtocol.IsVariablePolicyEnabled =
> ProtocolIsVariablePolicyEnabled;
> +  mVariablePolicyProtocol.RegisterVariablePolicy  =
> ProtocolRegisterVariablePolicy;
> +  mVariablePolicyProtocol.DumpVariablePolicy      =
> ProtocolDumpVariablePolicy;
> +  mVariablePolicyProtocol.LockVariablePolicy      = ProtocolLockVariablePolicy;
> +
> +  // Register all the protocols and return the status.
> +  Status = gBS->InstallMultipleProtocolInterfaces (
> +                  &ImageHandle,
> +                  &gEdkiiVariablePolicyProtocolGuid,
> +                  &mVariablePolicyProtocol,
> +                  NULL
> +                  );
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "%a - Failed to install protocol! %r\n",
> __FUNCTION__, Status));
> +    goto Exit;
> +  } else {
> +    ProtocolInstalled = TRUE;
> +  }
> +
> +  // Normally, we might want to register a callback
> +  // to lock the interface, but this is integrated
> +  // into the existing callbacks in VaraiableSmm.c
> +  // and VariableDxe.c.
> +
> +  //
> +  // Register a VirtualAddressChange callback for the MmComm protocol and
> Comm buffer.
> +  Status = gBS->CreateEventEx (
> +                  EVT_NOTIFY_SIGNAL,
> +                  TPL_NOTIFY,
> +                  VariablePolicyVirtualAddressCallback,
> +                  NULL,
> +                  &gEfiEventVirtualAddressChangeGuid,
> +                  &VirtualAddressChangeEvent
> +                  );
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "%a - Failed to create VirtualAddressChange
> event! %r\n", __FUNCTION__, Status));
> +    goto Exit;
> +  } else {
> +    VirtualAddressChangeRegistered = TRUE;
> +  }
> +
> +Exit:
> +  //
> +  // If we're about to return a failed status (and unload this driver), we must first
> undo anything that
> +  // has been successfully done.
> +  if (EFI_ERROR (Status)) {
> +    if (ProtocolInstalled) {
> +      gBS->UninstallProtocolInterface (&ImageHandle,
> &gEdkiiVariablePolicyProtocolGuid, &mVariablePolicyProtocol);
> +    }
> +
> +    if (VirtualAddressChangeRegistered) {
> +      gBS->CloseEvent (VirtualAddressChangeEvent);
> +    }
> +  }
> +
> +  return Status;
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeC
> ache.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeC
> ache.c
> new file mode 100644
> index 000000000000..9bb30bc1e804
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeC
> ache.c
> @@ -0,0 +1,158 @@
> +/** @file
> +  Functions related to managing the UEFI variable runtime cache. This file
> should only include functions
> +  used by the SMM UEFI variable driver.
> +
> +  Caution: This module requires additional review when modified.
> +  This driver will have external input - variable data. They may be input in SMM
> mode.
> +  This external input must be validated carefully to avoid security issue like
> +  buffer overflow, integer overflow.
> +
> +Copyright (c) 2019, Intel Corporation. All rights reserved.<BR>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include "VariableParsing.h"
> +#include "VariableRuntimeCache.h"
> +
> +extern VARIABLE_MODULE_GLOBAL  *mVariableModuleGlobal;
> +extern VARIABLE_STORE_HEADER   *mNvVariableCache;
> +
> +/**
> +  Copies any pending updates to runtime variable caches.
> +
> +  @retval EFI_UNSUPPORTED         The volatile store to be updated is not
> initialized properly.
> +  @retval EFI_SUCCESS             The volatile store was updated successfully.
> +
> +**/
> +EFI_STATUS
> +FlushPendingRuntimeVariableCacheUpdates (
> +  VOID
> +  )
> +{
> +  VARIABLE_RUNTIME_CACHE_CONTEXT  *VariableRuntimeCacheContext;
> +
> +  VariableRuntimeCacheContext = &mVariableModuleGlobal-
> >VariableGlobal.VariableRuntimeCacheContext;
> +
> +  if ((VariableRuntimeCacheContext->VariableRuntimeNvCache.Store == NULL)
> ||
> +      (VariableRuntimeCacheContext->VariableRuntimeVolatileCache.Store ==
> NULL) ||
> +      (VariableRuntimeCacheContext->PendingUpdate == NULL))
> +  {
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  if (*(VariableRuntimeCacheContext->PendingUpdate)) {
> +    if ((VariableRuntimeCacheContext->VariableRuntimeHobCache.Store !=
> NULL) &&
> +        (mVariableModuleGlobal->VariableGlobal.HobVariableBase > 0))
> +    {
> +      CopyMem (
> +        (VOID *)(
> +                 ((UINT8 *)(UINTN)VariableRuntimeCacheContext-
> >VariableRuntimeHobCache.Store) +
> +                 VariableRuntimeCacheContext-
> >VariableRuntimeHobCache.PendingUpdateOffset
> +                 ),
> +        (VOID *)(
> +                 ((UINT8 *)(UINTN)mVariableModuleGlobal-
> >VariableGlobal.HobVariableBase) +
> +                 VariableRuntimeCacheContext-
> >VariableRuntimeHobCache.PendingUpdateOffset
> +                 ),
> +        VariableRuntimeCacheContext-
> >VariableRuntimeHobCache.PendingUpdateLength
> +        );
> +      VariableRuntimeCacheContext-
> >VariableRuntimeHobCache.PendingUpdateLength = 0;
> +      VariableRuntimeCacheContext-
> >VariableRuntimeHobCache.PendingUpdateOffset = 0;
> +    }
> +
> +    CopyMem (
> +      (VOID *)(
> +               ((UINT8 *)(UINTN)VariableRuntimeCacheContext-
> >VariableRuntimeNvCache.Store) +
> +               VariableRuntimeCacheContext-
> >VariableRuntimeNvCache.PendingUpdateOffset
> +               ),
> +      (VOID *)(
> +               ((UINT8 *)(UINTN)mNvVariableCache) +
> +               VariableRuntimeCacheContext-
> >VariableRuntimeNvCache.PendingUpdateOffset
> +               ),
> +      VariableRuntimeCacheContext-
> >VariableRuntimeNvCache.PendingUpdateLength
> +      );
> +    VariableRuntimeCacheContext-
> >VariableRuntimeNvCache.PendingUpdateLength = 0;
> +    VariableRuntimeCacheContext-
> >VariableRuntimeNvCache.PendingUpdateOffset = 0;
> +
> +    CopyMem (
> +      (VOID *)(
> +               ((UINT8 *)(UINTN)VariableRuntimeCacheContext-
> >VariableRuntimeVolatileCache.Store) +
> +               VariableRuntimeCacheContext-
> >VariableRuntimeVolatileCache.PendingUpdateOffset
> +               ),
> +      (VOID *)(
> +               ((UINT8 *)(UINTN)mVariableModuleGlobal-
> >VariableGlobal.VolatileVariableBase) +
> +               VariableRuntimeCacheContext-
> >VariableRuntimeVolatileCache.PendingUpdateOffset
> +               ),
> +      VariableRuntimeCacheContext-
> >VariableRuntimeVolatileCache.PendingUpdateLength
> +      );
> +    VariableRuntimeCacheContext-
> >VariableRuntimeVolatileCache.PendingUpdateLength = 0;
> +    VariableRuntimeCacheContext-
> >VariableRuntimeVolatileCache.PendingUpdateOffset = 0;
> +    *(VariableRuntimeCacheContext->PendingUpdate)                                 = FALSE;
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Synchronizes the runtime variable caches with all pending updates outside
> runtime.
> +
> +  Ensures all conditions are met to maintain coherency for runtime cache
> updates. This function will attempt
> +  to write the given update (and any other pending updates) if the ReadLock is
> available. Otherwise, the
> +  update is added as a pending update for the given variable store and it will be
> flushed to the runtime cache
> +  at the next opportunity the ReadLock is available.
> +
> +  @param[in] VariableRuntimeCache Variable runtime cache structure for the
> runtime cache being synchronized.
> +  @param[in] Offset               Offset in bytes to apply the update.
> +  @param[in] Length               Length of data in bytes of the update.
> +
> +  @retval EFI_SUCCESS             The update was added as a pending update
> successfully. If the variable runtime
> +                                  cache ReadLock was available, the runtime cache was
> updated successfully.
> +  @retval EFI_UNSUPPORTED         The volatile store to be updated is not
> initialized properly.
> +
> +**/
> +EFI_STATUS
> +SynchronizeRuntimeVariableCache (
> +  IN  VARIABLE_RUNTIME_CACHE  *VariableRuntimeCache,
> +  IN  UINTN                   Offset,
> +  IN  UINTN                   Length
> +  )
> +{
> +  if (VariableRuntimeCache == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  } else if (VariableRuntimeCache->Store == NULL) {
> +    // The runtime cache may not be active or allocated yet.
> +    // In either case, return EFI_SUCCESS instead of EFI_NOT_AVAILABLE_YET.
> +    return EFI_SUCCESS;
> +  }
> +
> +  if ((mVariableModuleGlobal-
> >VariableGlobal.VariableRuntimeCacheContext.PendingUpdate == NULL) ||
> +      (mVariableModuleGlobal-
> >VariableGlobal.VariableRuntimeCacheContext.ReadLock == NULL))
> +  {
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  if (*(mVariableModuleGlobal-
> >VariableGlobal.VariableRuntimeCacheContext.PendingUpdate) &&
> +      (VariableRuntimeCache->PendingUpdateLength > 0))
> +  {
> +    VariableRuntimeCache->PendingUpdateLength =
> +      (UINT32)(
> +               MAX (
> +                 (UINTN)(VariableRuntimeCache->PendingUpdateOffset +
> VariableRuntimeCache->PendingUpdateLength),
> +                 Offset + Length
> +                 ) - MIN ((UINTN)VariableRuntimeCache->PendingUpdateOffset,
> Offset)
> +               );
> +    VariableRuntimeCache->PendingUpdateOffset =
> +      (UINT32)MIN ((UINTN)VariableRuntimeCache->PendingUpdateOffset,
> Offset);
> +  } else {
> +    VariableRuntimeCache->PendingUpdateLength = (UINT32)Length;
> +    VariableRuntimeCache->PendingUpdateOffset = (UINT32)Offset;
> +  }
> +
> +  *(mVariableModuleGlobal-
> >VariableGlobal.VariableRuntimeCacheContext.PendingUpdate) = TRUE;
> +
> +  if (*(mVariableModuleGlobal-
> >VariableGlobal.VariableRuntimeCacheContext.ReadLock) == FALSE) {
> +    return FlushPendingRuntimeVariableCacheUpdates ();
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmm.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmm.c
> new file mode 100644
> index 000000000000..f7bac0227577
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmm.c
> @@ -0,0 +1,1268 @@
> +/** @file
> +  The sample implementation for SMM variable protocol. And this driver
> +  implements an SMI handler to communicate with the DXE runtime driver
> +  to provide variable services.
> +
> +  Caution: This module requires additional review when modified.
> +  This driver will have external input - variable data and communicate buffer in
> SMM mode.
> +  This external input must be validated carefully to avoid security issue like
> +  buffer overflow, integer overflow.
> +
> +  SmmVariableHandler() will receive untrusted input and do basic validation.
> +
> +  Each sub function VariableServiceGetVariable(),
> VariableServiceGetNextVariableName(),
> +  VariableServiceSetVariable(), VariableServiceQueryVariableInfo(),
> ReclaimForOS(),
> +  SmmVariableGetStatistics() should also do validation based on its own
> knowledge.
> +
> +Copyright (c) 2010 - 2022, Intel Corporation. All rights reserved.<BR>
> +Copyright (c) 2018, Linaro, Ltd. All rights reserved.<BR>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <Protocol/SmmVariable.h>
> +#include <Protocol/SmmFirmwareVolumeBlock.h>
> +#include <Protocol/SmmFaultTolerantWrite.h>
> +#include <Protocol/MmEndOfDxe.h>
> +#include <Protocol/SmmVarCheck.h>
> +
> +#include <Library/MmServicesTableLib.h>
> +#include <Library/VariablePolicyLib.h>
> +
> +#include <Guid/SmmVariableCommon.h>
> +#include "Variable.h"
> +#include "VariableParsing.h"
> +#include "VariableRuntimeCache.h"
> +
> +extern VARIABLE_STORE_HEADER  *mNvVariableCache;
> +
> +BOOLEAN  mAtRuntime              = FALSE;
> +UINT8    *mVariableBufferPayload = NULL;
> +UINTN    mVariableBufferPayloadSize;
> +
> +/**
> +  SecureBoot Hook for SetVariable.
> +
> +  @param[in] VariableName                 Name of Variable to be found.
> +  @param[in] VendorGuid                   Variable vendor GUID.
> +
> +**/
> +VOID
> +EFIAPI
> +SecureBootHook (
> +  IN CHAR16    *VariableName,
> +  IN EFI_GUID  *VendorGuid
> +  )
> +{
> +  return;
> +}
> +
> +/**
> +
> +  This code sets variable in storage blocks (Volatile or Non-Volatile).
> +
> +  @param VariableName                     Name of Variable to be found.
> +  @param VendorGuid                       Variable vendor GUID.
> +  @param Attributes                       Attribute value of the variable found
> +  @param DataSize                         Size of Data found. If size is less than the
> +                                          data, this value contains the required size.
> +  @param Data                             Data pointer.
> +
> +  @return EFI_INVALID_PARAMETER           Invalid parameter.
> +  @return EFI_SUCCESS                     Set successfully.
> +  @return EFI_OUT_OF_RESOURCES            Resource not enough to set variable.
> +  @return EFI_NOT_FOUND                   Not found.
> +  @return EFI_WRITE_PROTECTED             Variable is read-only.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +SmmVariableSetVariable (
> +  IN CHAR16    *VariableName,
> +  IN EFI_GUID  *VendorGuid,
> +  IN UINT32    Attributes,
> +  IN UINTN     DataSize,
> +  IN VOID      *Data
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  //
> +  // Disable write protection when the calling SetVariable() through
> EFI_SMM_VARIABLE_PROTOCOL.
> +  //
> +  mRequestSource = VarCheckFromTrusted;
> +  Status         = VariableServiceSetVariable (
> +                     VariableName,
> +                     VendorGuid,
> +                     Attributes,
> +                     DataSize,
> +                     Data
> +                     );
> +  mRequestSource = VarCheckFromUntrusted;
> +  return Status;
> +}
> +
> +EFI_SMM_VARIABLE_PROTOCOL  gSmmVariable = {
> +  VariableServiceGetVariable,
> +  VariableServiceGetNextVariableName,
> +  SmmVariableSetVariable,
> +  VariableServiceQueryVariableInfo
> +};
> +
> +EDKII_SMM_VAR_CHECK_PROTOCOL  mSmmVarCheck = {
> +  VarCheckRegisterSetVariableCheckHandler,
> +  VarCheckVariablePropertySet,
> +  VarCheckVariablePropertyGet
> +};
> +
> +/**
> +  Return TRUE if ExitBootServices () has been called.
> +
> +  @retval TRUE If ExitBootServices () has been called.
> +**/
> +BOOLEAN
> +AtRuntime (
> +  VOID
> +  )
> +{
> +  return mAtRuntime;
> +}
> +
> +/**
> +  Initializes a basic mutual exclusion lock.
> +
> +  This function initializes a basic mutual exclusion lock to the released state
> +  and returns the lock.  Each lock provides mutual exclusion access at its task
> +  priority level.  Since there is no preemption or multiprocessor support in EFI,
> +  acquiring the lock only consists of raising to the locks TPL.
> +  If Lock is NULL, then ASSERT().
> +  If Priority is not a valid TPL value, then ASSERT().
> +
> +  @param  Lock       A pointer to the lock data structure to initialize.
> +  @param  Priority   EFI TPL is associated with the lock.
> +
> +  @return The lock.
> +
> +**/
> +EFI_LOCK *
> +InitializeLock (
> +  IN OUT EFI_LOCK  *Lock,
> +  IN EFI_TPL       Priority
> +  )
> +{
> +  return Lock;
> +}
> +
> +/**
> +  Acquires lock only at boot time. Simply returns at runtime.
> +
> +  This is a temperary function that will be removed when
> +  EfiAcquireLock() in UefiLib can handle the call in UEFI
> +  Runtimer driver in RT phase.
> +  It calls EfiAcquireLock() at boot time, and simply returns
> +  at runtime.
> +
> +  @param  Lock         A pointer to the lock to acquire.
> +
> +**/
> +VOID
> +AcquireLockOnlyAtBootTime (
> +  IN EFI_LOCK  *Lock
> +  )
> +{
> +}
> +
> +/**
> +  Releases lock only at boot time. Simply returns at runtime.
> +
> +  This is a temperary function which will be removed when
> +  EfiReleaseLock() in UefiLib can handle the call in UEFI
> +  Runtimer driver in RT phase.
> +  It calls EfiReleaseLock() at boot time and simply returns
> +  at runtime.
> +
> +  @param  Lock         A pointer to the lock to release.
> +
> +**/
> +VOID
> +ReleaseLockOnlyAtBootTime (
> +  IN EFI_LOCK  *Lock
> +  )
> +{
> +}
> +
> +/**
> +  Retrieve the SMM Fault Tolerent Write protocol interface.
> +
> +  @param[out] FtwProtocol       The interface of SMM Ftw protocol
> +
> +  @retval EFI_SUCCESS           The SMM FTW protocol instance was found and
> returned in FtwProtocol.
> +  @retval EFI_NOT_FOUND         The SMM FTW protocol instance was not
> found.
> +  @retval EFI_INVALID_PARAMETER SarProtocol is NULL.
> +
> +**/
> +EFI_STATUS
> +GetFtwProtocol (
> +  OUT VOID  **FtwProtocol
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  //
> +  // Locate Smm Fault Tolerent Write protocol
> +  //
> +  Status = gMmst->MmLocateProtocol (
> +                    &gEfiSmmFaultTolerantWriteProtocolGuid,
> +                    NULL,
> +                    FtwProtocol
> +                    );
> +  return Status;
> +}
> +
> +/**
> +  Retrieve the SMM FVB protocol interface by HANDLE.
> +
> +  @param[in]  FvBlockHandle     The handle of SMM FVB protocol that provides
> services for
> +                                reading, writing, and erasing the target block.
> +  @param[out] FvBlock           The interface of SMM FVB protocol
> +
> +  @retval EFI_SUCCESS           The interface information for the specified
> protocol was returned.
> +  @retval EFI_UNSUPPORTED       The device does not support the SMM FVB
> protocol.
> +  @retval EFI_INVALID_PARAMETER FvBlockHandle is not a valid EFI_HANDLE
> or FvBlock is NULL.
> +
> +**/
> +EFI_STATUS
> +GetFvbByHandle (
> +  IN  EFI_HANDLE                          FvBlockHandle,
> +  OUT EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  **FvBlock
> +  )
> +{
> +  //
> +  // To get the SMM FVB protocol interface on the handle
> +  //
> +  return gMmst->MmHandleProtocol (
> +                  FvBlockHandle,
> +                  &gEfiSmmFirmwareVolumeBlockProtocolGuid,
> +                  (VOID **)FvBlock
> +                  );
> +}
> +
> +/**
> +  Function returns an array of handles that support the SMM FVB protocol
> +  in a buffer allocated from pool.
> +
> +  @param[out]  NumberHandles    The number of handles returned in Buffer.
> +  @param[out]  Buffer           A pointer to the buffer to return the requested
> +                                array of  handles that support SMM FVB protocol.
> +
> +  @retval EFI_SUCCESS           The array of handles was returned in Buffer, and
> the number of
> +                                handles in Buffer was returned in NumberHandles.
> +  @retval EFI_NOT_FOUND         No SMM FVB handle was found.
> +  @retval EFI_OUT_OF_RESOURCES  There is not enough pool memory to store
> the matching results.
> +  @retval EFI_INVALID_PARAMETER NumberHandles is NULL or Buffer is NULL.
> +
> +**/
> +EFI_STATUS
> +GetFvbCountAndBuffer (
> +  OUT UINTN       *NumberHandles,
> +  OUT EFI_HANDLE  **Buffer
> +  )
> +{
> +  EFI_STATUS  Status;
> +  UINTN       BufferSize;
> +
> +  if ((NumberHandles == NULL) || (Buffer == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  BufferSize     = 0;
> +  *NumberHandles = 0;
> +  *Buffer        = NULL;
> +  Status         = gMmst->MmLocateHandle (
> +                            ByProtocol,
> +                            &gEfiSmmFirmwareVolumeBlockProtocolGuid,
> +                            NULL,
> +                            &BufferSize,
> +                            *Buffer
> +                            );
> +  if (EFI_ERROR (Status) && (Status != EFI_BUFFER_TOO_SMALL)) {
> +    return EFI_NOT_FOUND;
> +  }
> +
> +  *Buffer = AllocatePool (BufferSize);
> +  if (*Buffer == NULL) {
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +
> +  Status = gMmst->MmLocateHandle (
> +                    ByProtocol,
> +                    &gEfiSmmFirmwareVolumeBlockProtocolGuid,
> +                    NULL,
> +                    &BufferSize,
> +                    *Buffer
> +                    );
> +
> +  *NumberHandles = BufferSize / sizeof (EFI_HANDLE);
> +  if (EFI_ERROR (Status)) {
> +    *NumberHandles = 0;
> +    FreePool (*Buffer);
> +    *Buffer = NULL;
> +  }
> +
> +  return Status;
> +}
> +
> +/**
> +  Get the variable statistics information from the information buffer pointed by
> gVariableInfo.
> +
> +  Caution: This function may be invoked at SMM runtime.
> +  InfoEntry and InfoSize are external input. Care must be taken to make sure
> not security issue at runtime.
> +
> +  @param[in, out]  InfoEntry    A pointer to the buffer of variable information
> entry.
> +                                On input, point to the variable information returned last time.
> if
> +                                InfoEntry->VendorGuid is zero, return the first information.
> +                                On output, point to the next variable information.
> +  @param[in, out]  InfoSize     On input, the size of the variable information
> buffer.
> +                                On output, the returned variable information size.
> +
> +  @retval EFI_SUCCESS           The variable information is found and returned
> successfully.
> +  @retval EFI_UNSUPPORTED       No variable inoformation exists in variable
> driver. The
> +                                PcdVariableCollectStatistics should be set TRUE to support it.
> +  @retval EFI_BUFFER_TOO_SMALL  The buffer is too small to hold the next
> variable information.
> +  @retval EFI_INVALID_PARAMETER Input parameter is invalid.
> +
> +**/
> +EFI_STATUS
> +SmmVariableGetStatistics (
> +  IN OUT VARIABLE_INFO_ENTRY  *InfoEntry,
> +  IN OUT UINTN                *InfoSize
> +  )
> +{
> +  VARIABLE_INFO_ENTRY  *VariableInfo;
> +  UINTN                NameSize;
> +  UINTN                StatisticsInfoSize;
> +  CHAR16               *InfoName;
> +  UINTN                InfoNameMaxSize;
> +  EFI_GUID             VendorGuid;
> +
> +  if (InfoEntry == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  VariableInfo = gVariableInfo;
> +  if (VariableInfo == NULL) {
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  StatisticsInfoSize = sizeof (VARIABLE_INFO_ENTRY);
> +  if (*InfoSize < StatisticsInfoSize) {
> +    *InfoSize = StatisticsInfoSize;
> +    return EFI_BUFFER_TOO_SMALL;
> +  }
> +
> +  InfoName        = (CHAR16 *)(InfoEntry + 1);
> +  InfoNameMaxSize = (*InfoSize - sizeof (VARIABLE_INFO_ENTRY));
> +
> +  CopyGuid (&VendorGuid, &InfoEntry->VendorGuid);
> +
> +  if (IsZeroGuid (&VendorGuid)) {
> +    //
> +    // Return the first variable info
> +    //
> +    NameSize           = StrSize (VariableInfo->Name);
> +    StatisticsInfoSize = sizeof (VARIABLE_INFO_ENTRY) + NameSize;
> +    if (*InfoSize < StatisticsInfoSize) {
> +      *InfoSize = StatisticsInfoSize;
> +      return EFI_BUFFER_TOO_SMALL;
> +    }
> +
> +    CopyMem (InfoEntry, VariableInfo, sizeof (VARIABLE_INFO_ENTRY));
> +    CopyMem (InfoName, VariableInfo->Name, NameSize);
> +    *InfoSize = StatisticsInfoSize;
> +    return EFI_SUCCESS;
> +  }
> +
> +  //
> +  // Get the next variable info
> +  //
> +  while (VariableInfo != NULL) {
> +    if (CompareGuid (&VariableInfo->VendorGuid, &VendorGuid)) {
> +      NameSize = StrSize (VariableInfo->Name);
> +      if (NameSize <= InfoNameMaxSize) {
> +        if (CompareMem (VariableInfo->Name, InfoName, NameSize) == 0) {
> +          //
> +          // Find the match one
> +          //
> +          VariableInfo = VariableInfo->Next;
> +          break;
> +        }
> +      }
> +    }
> +
> +    VariableInfo = VariableInfo->Next;
> +  }
> +
> +  if (VariableInfo == NULL) {
> +    *InfoSize = 0;
> +    return EFI_SUCCESS;
> +  }
> +
> +  //
> +  // Output the new variable info
> +  //
> +  NameSize           = StrSize (VariableInfo->Name);
> +  StatisticsInfoSize = sizeof (VARIABLE_INFO_ENTRY) + NameSize;
> +  if (*InfoSize < StatisticsInfoSize) {
> +    *InfoSize = StatisticsInfoSize;
> +    return EFI_BUFFER_TOO_SMALL;
> +  }
> +
> +  CopyMem (InfoEntry, VariableInfo, sizeof (VARIABLE_INFO_ENTRY));
> +  CopyMem (InfoName, VariableInfo->Name, NameSize);
> +  *InfoSize = StatisticsInfoSize;
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Communication service SMI Handler entry.
> +
> +  This SMI handler provides services for the variable wrapper driver.
> +
> +  Caution: This function may receive untrusted input.
> +  This variable data and communicate buffer are external input, so this function
> will do basic validation.
> +  Each sub function VariableServiceGetVariable(),
> VariableServiceGetNextVariableName(),
> +  VariableServiceSetVariable(), VariableServiceQueryVariableInfo(),
> ReclaimForOS(),
> +  SmmVariableGetStatistics() should also do validation based on its own
> knowledge.
> +
> +  @param[in]     DispatchHandle  The unique handle assigned to this handler by
> SmiHandlerRegister().
> +  @param[in]     RegisterContext Points to an optional handler context which
> was specified when the
> +                                 handler was registered.
> +  @param[in, out] CommBuffer     A pointer to a collection of data in memory
> that will
> +                                 be conveyed from a non-SMM environment into an SMM
> environment.
> +  @param[in, out] CommBufferSize The size of the CommBuffer.
> +
> +  @retval EFI_SUCCESS                         The interrupt was handled and quiesced.
> No other handlers
> +                                              should still be called.
> +  @retval EFI_WARN_INTERRUPT_SOURCE_QUIESCED  The interrupt has been
> quiesced but other handlers should
> +                                              still be called.
> +  @retval EFI_WARN_INTERRUPT_SOURCE_PENDING   The interrupt is still
> pending and other handlers should still
> +                                              be called.
> +  @retval EFI_INTERRUPT_PENDING               The interrupt could not be
> quiesced.
> +**/
> +EFI_STATUS
> +EFIAPI
> +SmmVariableHandler (
> +  IN     EFI_HANDLE  DispatchHandle,
> +  IN     CONST VOID  *RegisterContext,
> +  IN OUT VOID        *CommBuffer,
> +  IN OUT UINTN       *CommBufferSize
> +  )
> +{
> +  EFI_STATUS                                               Status;
> +  SMM_VARIABLE_COMMUNICATE_HEADER
> *SmmVariableFunctionHeader;
> +  SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE
> *SmmVariableHeader;
> +  SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME
> *GetNextVariableName;
> +  SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO
> *QueryVariableInfo;
> +  SMM_VARIABLE_COMMUNICATE_GET_PAYLOAD_SIZE
> *GetPayloadSize;
> +  SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT
> *RuntimeVariableCacheContext;
> +  SMM_VARIABLE_COMMUNICATE_GET_RUNTIME_CACHE_INFO
> *GetRuntimeCacheInfo;
> +  SMM_VARIABLE_COMMUNICATE_LOCK_VARIABLE
> *VariableToLock;
> +  SMM_VARIABLE_COMMUNICATE_VAR_CHECK_VARIABLE_PROPERTY
> *CommVariableProperty;
> +  VARIABLE_INFO_ENTRY                                      *VariableInfo;
> +  VARIABLE_RUNTIME_CACHE_CONTEXT                           *VariableCacheContext;
> +  VARIABLE_STORE_HEADER                                    *VariableCache;
> +  UINTN                                                    InfoSize;
> +  UINTN                                                    NameBufferSize;
> +  UINTN                                                    CommBufferPayloadSize;
> +  UINTN                                                    TempCommBufferSize;
> +
> +  //
> +  // If input is invalid, stop processing this SMI
> +  //
> +  if ((CommBuffer == NULL) || (CommBufferSize == NULL)) {
> +    return EFI_SUCCESS;
> +  }
> +
> +  TempCommBufferSize = *CommBufferSize;
> +
> +  if (TempCommBufferSize < SMM_VARIABLE_COMMUNICATE_HEADER_SIZE) {
> +    DEBUG ((DEBUG_ERROR, "SmmVariableHandler: SMM communication buffer
> size invalid!\n"));
> +    return EFI_SUCCESS;
> +  }
> +
> +  CommBufferPayloadSize = TempCommBufferSize -
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE;
> +  if (CommBufferPayloadSize > mVariableBufferPayloadSize) {
> +    DEBUG ((DEBUG_ERROR, "SmmVariableHandler: SMM communication buffer
> payload size invalid!\n"));
> +    return EFI_SUCCESS;
> +  }
> +
> +  if (!VariableSmmIsBufferOutsideSmmValid ((UINTN)CommBuffer,
> TempCommBufferSize)) {
> +    DEBUG ((DEBUG_ERROR, "SmmVariableHandler: SMM communication buffer
> in SMRAM or overflow!\n"));
> +    return EFI_SUCCESS;
> +  }
> +
> +  SmmVariableFunctionHeader = (SMM_VARIABLE_COMMUNICATE_HEADER
> *)CommBuffer;
> +  switch (SmmVariableFunctionHeader->Function) {
> +    case SMM_VARIABLE_FUNCTION_GET_VARIABLE:
> +      if (CommBufferPayloadSize < OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)) {
> +        DEBUG ((DEBUG_ERROR, "GetVariable: SMM communication buffer size
> invalid!\n"));
> +        return EFI_SUCCESS;
> +      }
> +
> +      //
> +      // Copy the input communicate buffer payload to pre-allocated SMM
> variable buffer payload.
> +      //
> +      CopyMem (mVariableBufferPayload, SmmVariableFunctionHeader->Data,
> CommBufferPayloadSize);
> +      SmmVariableHeader =
> (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE
> *)mVariableBufferPayload;
> +      if (((UINTN)(~0) - SmmVariableHeader->DataSize < OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)) ||
> +          ((UINTN)(~0) - SmmVariableHeader->NameSize < OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) +
> SmmVariableHeader->DataSize))
> +      {
> +        //
> +        // Prevent InfoSize overflow happen
> +        //
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      InfoSize = OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)
> +                 + SmmVariableHeader->DataSize + SmmVariableHeader->NameSize;
> +
> +      //
> +      // SMRAM range check already covered before
> +      //
> +      if (InfoSize > CommBufferPayloadSize) {
> +        DEBUG ((DEBUG_ERROR, "GetVariable: Data size exceed communication
> buffer size limit!\n"));
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      //
> +      // The VariableSpeculationBarrier() call here is to ensure the previous
> +      // range/content checks for the CommBuffer have been completed before
> the
> +      // subsequent consumption of the CommBuffer content.
> +      //
> +      VariableSpeculationBarrier ();
> +      if ((SmmVariableHeader->NameSize < sizeof (CHAR16)) ||
> (SmmVariableHeader->Name[SmmVariableHeader->NameSize/sizeof (CHAR16) -
> 1] != L'\0')) {
> +        //
> +        // Make sure VariableName is A Null-terminated string.
> +        //
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      Status = VariableServiceGetVariable (
> +                 SmmVariableHeader->Name,
> +                 &SmmVariableHeader->Guid,
> +                 &SmmVariableHeader->Attributes,
> +                 &SmmVariableHeader->DataSize,
> +                 (UINT8 *)SmmVariableHeader->Name + SmmVariableHeader-
> >NameSize
> +                 );
> +      CopyMem (SmmVariableFunctionHeader->Data, mVariableBufferPayload,
> CommBufferPayloadSize);
> +      break;
> +
> +    case SMM_VARIABLE_FUNCTION_GET_NEXT_VARIABLE_NAME:
> +      if (CommBufferPayloadSize < OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name)) {
> +        DEBUG ((DEBUG_ERROR, "GetNextVariableName: SMM communication
> buffer size invalid!\n"));
> +        return EFI_SUCCESS;
> +      }
> +
> +      //
> +      // Copy the input communicate buffer payload to pre-allocated SMM
> variable buffer payload.
> +      //
> +      CopyMem (mVariableBufferPayload, SmmVariableFunctionHeader->Data,
> CommBufferPayloadSize);
> +      GetNextVariableName =
> (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME
> *)mVariableBufferPayload;
> +      if ((UINTN)(~0) - GetNextVariableName->NameSize < OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name)) {
> +        //
> +        // Prevent InfoSize overflow happen
> +        //
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      InfoSize = OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name) +
> GetNextVariableName->NameSize;
> +
> +      //
> +      // SMRAM range check already covered before
> +      //
> +      if (InfoSize > CommBufferPayloadSize) {
> +        DEBUG ((DEBUG_ERROR, "GetNextVariableName: Data size exceed
> communication buffer size limit!\n"));
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      NameBufferSize = CommBufferPayloadSize - OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name);
> +      if ((NameBufferSize < sizeof (CHAR16)) || (GetNextVariableName-
> >Name[NameBufferSize/sizeof (CHAR16) - 1] != L'\0')) {
> +        //
> +        // Make sure input VariableName is A Null-terminated string.
> +        //
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      Status = VariableServiceGetNextVariableName (
> +                 &GetNextVariableName->NameSize,
> +                 GetNextVariableName->Name,
> +                 &GetNextVariableName->Guid
> +                 );
> +      CopyMem (SmmVariableFunctionHeader->Data, mVariableBufferPayload,
> CommBufferPayloadSize);
> +      break;
> +
> +    case SMM_VARIABLE_FUNCTION_SET_VARIABLE:
> +      if (CommBufferPayloadSize < OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)) {
> +        DEBUG ((DEBUG_ERROR, "SetVariable: SMM communication buffer size
> invalid!\n"));
> +        return EFI_SUCCESS;
> +      }
> +
> +      //
> +      // Copy the input communicate buffer payload to pre-allocated SMM
> variable buffer payload.
> +      //
> +      CopyMem (mVariableBufferPayload, SmmVariableFunctionHeader->Data,
> CommBufferPayloadSize);
> +      SmmVariableHeader =
> (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE
> *)mVariableBufferPayload;
> +      if (((UINTN)(~0) - SmmVariableHeader->DataSize < OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)) ||
> +          ((UINTN)(~0) - SmmVariableHeader->NameSize < OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) +
> SmmVariableHeader->DataSize))
> +      {
> +        //
> +        // Prevent InfoSize overflow happen
> +        //
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      InfoSize = OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)
> +                 + SmmVariableHeader->DataSize + SmmVariableHeader->NameSize;
> +
> +      //
> +      // SMRAM range check already covered before
> +      // Data buffer should not contain SMM range
> +      //
> +      if (InfoSize > CommBufferPayloadSize) {
> +        DEBUG ((DEBUG_ERROR, "SetVariable: Data size exceed communication
> buffer size limit!\n"));
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      //
> +      // The VariableSpeculationBarrier() call here is to ensure the previous
> +      // range/content checks for the CommBuffer have been completed before
> the
> +      // subsequent consumption of the CommBuffer content.
> +      //
> +      VariableSpeculationBarrier ();
> +      if ((SmmVariableHeader->NameSize < sizeof (CHAR16)) ||
> (SmmVariableHeader->Name[SmmVariableHeader->NameSize/sizeof (CHAR16) -
> 1] != L'\0')) {
> +        //
> +        // Make sure VariableName is A Null-terminated string.
> +        //
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      Status = VariableServiceSetVariable (
> +                 SmmVariableHeader->Name,
> +                 &SmmVariableHeader->Guid,
> +                 SmmVariableHeader->Attributes,
> +                 SmmVariableHeader->DataSize,
> +                 (UINT8 *)SmmVariableHeader->Name + SmmVariableHeader-
> >NameSize
> +                 );
> +      break;
> +
> +    case SMM_VARIABLE_FUNCTION_QUERY_VARIABLE_INFO:
> +      if (CommBufferPayloadSize < sizeof
> (SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO)) {
> +        DEBUG ((DEBUG_ERROR, "QueryVariableInfo: SMM communication buffer
> size invalid!\n"));
> +        return EFI_SUCCESS;
> +      }
> +
> +      QueryVariableInfo =
> (SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO
> *)SmmVariableFunctionHeader->Data;
> +
> +      Status = VariableServiceQueryVariableInfo (
> +                 QueryVariableInfo->Attributes,
> +                 &QueryVariableInfo->MaximumVariableStorageSize,
> +                 &QueryVariableInfo->RemainingVariableStorageSize,
> +                 &QueryVariableInfo->MaximumVariableSize
> +                 );
> +      break;
> +
> +    case SMM_VARIABLE_FUNCTION_GET_PAYLOAD_SIZE:
> +      if (CommBufferPayloadSize < sizeof
> (SMM_VARIABLE_COMMUNICATE_GET_PAYLOAD_SIZE)) {
> +        DEBUG ((DEBUG_ERROR, "GetPayloadSize: SMM communication buffer
> size invalid!\n"));
> +        return EFI_SUCCESS;
> +      }
> +
> +      GetPayloadSize                      =
> (SMM_VARIABLE_COMMUNICATE_GET_PAYLOAD_SIZE
> *)SmmVariableFunctionHeader->Data;
> +      GetPayloadSize->VariablePayloadSize = mVariableBufferPayloadSize;
> +      Status                              = EFI_SUCCESS;
> +      break;
> +
> +    case SMM_VARIABLE_FUNCTION_READY_TO_BOOT:
> +      if (AtRuntime ()) {
> +        Status = EFI_UNSUPPORTED;
> +        break;
> +      }
> +
> +      if (!mEndOfDxe) {
> +        MorLockInitAtEndOfDxe ();
> +        Status = LockVariablePolicy ();
> +        ASSERT_EFI_ERROR (Status);
> +        mEndOfDxe = TRUE;
> +        VarCheckLibInitializeAtEndOfDxe (NULL);
> +        //
> +        // The initialization for variable quota.
> +        //
> +        InitializeVariableQuota ();
> +      }
> +
> +      ReclaimForOS ();
> +      Status = EFI_SUCCESS;
> +      break;
> +
> +    case SMM_VARIABLE_FUNCTION_EXIT_BOOT_SERVICE:
> +      mAtRuntime = TRUE;
> +      Status     = EFI_SUCCESS;
> +      break;
> +
> +    case SMM_VARIABLE_FUNCTION_GET_STATISTICS:
> +      VariableInfo = (VARIABLE_INFO_ENTRY *)SmmVariableFunctionHeader-
> >Data;
> +      InfoSize     = TempCommBufferSize -
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE;
> +
> +      //
> +      // Do not need to check SmmVariableFunctionHeader->Data in SMRAM
> here.
> +      // It is covered by previous CommBuffer check
> +      //
> +
> +      //
> +      // Do not need to check CommBufferSize buffer as it should point to
> SMRAM
> +      // that was used by SMM core to cache CommSize from
> SmmCommunication protocol.
> +      //
> +
> +      Status          = SmmVariableGetStatistics (VariableInfo, &InfoSize);
> +      *CommBufferSize = InfoSize +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE;
> +      break;
> +
> +    case SMM_VARIABLE_FUNCTION_LOCK_VARIABLE:
> +      if (mEndOfDxe) {
> +        Status = EFI_ACCESS_DENIED;
> +      } else {
> +        VariableToLock = (SMM_VARIABLE_COMMUNICATE_LOCK_VARIABLE
> *)SmmVariableFunctionHeader->Data;
> +        Status         = VariableLockRequestToLock (
> +                           NULL,
> +                           VariableToLock->Name,
> +                           &VariableToLock->Guid
> +                           );
> +      }
> +
> +      break;
> +    case SMM_VARIABLE_FUNCTION_VAR_CHECK_VARIABLE_PROPERTY_SET:
> +      if (mEndOfDxe) {
> +        Status = EFI_ACCESS_DENIED;
> +      } else {
> +        CommVariableProperty =
> (SMM_VARIABLE_COMMUNICATE_VAR_CHECK_VARIABLE_PROPERTY
> *)SmmVariableFunctionHeader->Data;
> +        Status               = VarCheckVariablePropertySet (
> +                                 CommVariableProperty->Name,
> +                                 &CommVariableProperty->Guid,
> +                                 &CommVariableProperty->VariableProperty
> +                                 );
> +      }
> +
> +      break;
> +    case SMM_VARIABLE_FUNCTION_VAR_CHECK_VARIABLE_PROPERTY_GET:
> +      if (CommBufferPayloadSize < OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_VAR_CHECK_VARIABLE_PROPERTY, Name))
> {
> +        DEBUG ((DEBUG_ERROR, "VarCheckVariablePropertyGet: SMM
> communication buffer size invalid!\n"));
> +        return EFI_SUCCESS;
> +      }
> +
> +      //
> +      // Copy the input communicate buffer payload to pre-allocated SMM
> variable buffer payload.
> +      //
> +      CopyMem (mVariableBufferPayload, SmmVariableFunctionHeader->Data,
> CommBufferPayloadSize);
> +      CommVariableProperty =
> (SMM_VARIABLE_COMMUNICATE_VAR_CHECK_VARIABLE_PROPERTY
> *)mVariableBufferPayload;
> +      if ((UINTN)(~0) - CommVariableProperty->NameSize < OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_VAR_CHECK_VARIABLE_PROPERTY, Name))
> {
> +        //
> +        // Prevent InfoSize overflow happen
> +        //
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      InfoSize = OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_VAR_CHECK_VARIABLE_PROPERTY, Name) +
> CommVariableProperty->NameSize;
> +
> +      //
> +      // SMRAM range check already covered before
> +      //
> +      if (InfoSize > CommBufferPayloadSize) {
> +        DEBUG ((DEBUG_ERROR, "VarCheckVariablePropertyGet: Data size exceed
> communication buffer size limit!\n"));
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      //
> +      // The VariableSpeculationBarrier() call here is to ensure the previous
> +      // range/content checks for the CommBuffer have been completed before
> the
> +      // subsequent consumption of the CommBuffer content.
> +      //
> +      VariableSpeculationBarrier ();
> +      if ((CommVariableProperty->NameSize < sizeof (CHAR16)) ||
> (CommVariableProperty->Name[CommVariableProperty->NameSize/sizeof
> (CHAR16) - 1] != L'\0')) {
> +        //
> +        // Make sure VariableName is A Null-terminated string.
> +        //
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      Status = VarCheckVariablePropertyGet (
> +                 CommVariableProperty->Name,
> +                 &CommVariableProperty->Guid,
> +                 &CommVariableProperty->VariableProperty
> +                 );
> +      CopyMem (SmmVariableFunctionHeader->Data, mVariableBufferPayload,
> CommBufferPayloadSize);
> +      break;
> +    case
> SMM_VARIABLE_FUNCTION_INIT_RUNTIME_VARIABLE_CACHE_CONTEXT:
> +      if (CommBufferPayloadSize < sizeof
> (SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT)) {
> +        DEBUG ((DEBUG_ERROR, "InitRuntimeVariableCacheContext: SMM
> communication buffer size invalid!\n"));
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      if (mEndOfDxe) {
> +        DEBUG ((DEBUG_ERROR, "InitRuntimeVariableCacheContext: Cannot init
> context after end of DXE!\n"));
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      //
> +      // Copy the input communicate buffer payload to the pre-allocated SMM
> variable payload buffer.
> +      //
> +      CopyMem (mVariableBufferPayload, SmmVariableFunctionHeader->Data,
> CommBufferPayloadSize);
> +      RuntimeVariableCacheContext =
> (SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT
> *)mVariableBufferPayload;
> +
> +      //
> +      // Verify required runtime cache buffers are provided.
> +      //
> +      if ((RuntimeVariableCacheContext->RuntimeVolatileCache == NULL) ||
> +          (RuntimeVariableCacheContext->RuntimeNvCache == NULL) ||
> +          (RuntimeVariableCacheContext->PendingUpdate == NULL) ||
> +          (RuntimeVariableCacheContext->ReadLock == NULL) ||
> +          (RuntimeVariableCacheContext->HobFlushComplete == NULL))
> +      {
> +        DEBUG ((DEBUG_ERROR, "InitRuntimeVariableCacheContext: Required
> runtime cache buffer is NULL!\n"));
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      //
> +      // Verify minimum size requirements for the runtime variable store buffers.
> +      //
> +      if (((RuntimeVariableCacheContext->RuntimeHobCache != NULL) &&
> +           (RuntimeVariableCacheContext->RuntimeHobCache->Size < sizeof
> (VARIABLE_STORE_HEADER))) ||
> +          (RuntimeVariableCacheContext->RuntimeVolatileCache->Size < sizeof
> (VARIABLE_STORE_HEADER)) ||
> +          (RuntimeVariableCacheContext->RuntimeNvCache->Size < sizeof
> (VARIABLE_STORE_HEADER)))
> +      {
> +        DEBUG ((DEBUG_ERROR, "InitRuntimeVariableCacheContext: A runtime
> cache buffer size is invalid!\n"));
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      //
> +      // Verify runtime buffers do not overlap with SMRAM ranges.
> +      //
> +      if ((RuntimeVariableCacheContext->RuntimeHobCache != NULL) &&
> +          !VariableSmmIsBufferOutsideSmmValid (
> +             (UINTN)RuntimeVariableCacheContext->RuntimeHobCache,
> +             (UINTN)RuntimeVariableCacheContext->RuntimeHobCache->Size
> +             ))
> +      {
> +        DEBUG ((DEBUG_ERROR, "InitRuntimeVariableCacheContext: Runtime
> HOB cache buffer in SMRAM or overflow!\n"));
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      if (!VariableSmmIsBufferOutsideSmmValid (
> +             (UINTN)RuntimeVariableCacheContext->RuntimeVolatileCache,
> +             (UINTN)RuntimeVariableCacheContext->RuntimeVolatileCache->Size
> +             ))
> +      {
> +        DEBUG ((DEBUG_ERROR, "InitRuntimeVariableCacheContext: Runtime
> volatile cache buffer in SMRAM or overflow!\n"));
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      if (!VariableSmmIsBufferOutsideSmmValid (
> +             (UINTN)RuntimeVariableCacheContext->RuntimeNvCache,
> +             (UINTN)RuntimeVariableCacheContext->RuntimeNvCache->Size
> +             ))
> +      {
> +        DEBUG ((DEBUG_ERROR, "InitRuntimeVariableCacheContext: Runtime
> non-volatile cache buffer in SMRAM or overflow!\n"));
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      if (!VariableSmmIsBufferOutsideSmmValid (
> +             (UINTN)RuntimeVariableCacheContext->PendingUpdate,
> +             sizeof (*(RuntimeVariableCacheContext->PendingUpdate))
> +             ))
> +      {
> +        DEBUG ((DEBUG_ERROR, "InitRuntimeVariableCacheContext: Runtime
> cache pending update buffer in SMRAM or overflow!\n"));
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      if (!VariableSmmIsBufferOutsideSmmValid (
> +             (UINTN)RuntimeVariableCacheContext->ReadLock,
> +             sizeof (*(RuntimeVariableCacheContext->ReadLock))
> +             ))
> +      {
> +        DEBUG ((DEBUG_ERROR, "InitRuntimeVariableCacheContext: Runtime
> cache read lock buffer in SMRAM or overflow!\n"));
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      if (!VariableSmmIsBufferOutsideSmmValid (
> +             (UINTN)RuntimeVariableCacheContext->HobFlushComplete,
> +             sizeof (*(RuntimeVariableCacheContext->HobFlushComplete))
> +             ))
> +      {
> +        DEBUG ((DEBUG_ERROR, "InitRuntimeVariableCacheContext: Runtime
> cache HOB flush complete buffer in SMRAM or overflow!\n"));
> +        Status = EFI_ACCESS_DENIED;
> +        goto EXIT;
> +      }
> +
> +      VariableCacheContext                                     = &mVariableModuleGlobal-
> >VariableGlobal.VariableRuntimeCacheContext;
> +      VariableCacheContext->VariableRuntimeHobCache.Store      =
> RuntimeVariableCacheContext->RuntimeHobCache;
> +      VariableCacheContext->VariableRuntimeVolatileCache.Store =
> RuntimeVariableCacheContext->RuntimeVolatileCache;
> +      VariableCacheContext->VariableRuntimeNvCache.Store       =
> RuntimeVariableCacheContext->RuntimeNvCache;
> +      VariableCacheContext->PendingUpdate                      =
> RuntimeVariableCacheContext->PendingUpdate;
> +      VariableCacheContext->ReadLock                           =
> RuntimeVariableCacheContext->ReadLock;
> +      VariableCacheContext->HobFlushComplete                   =
> RuntimeVariableCacheContext->HobFlushComplete;
> +
> +      // Set up the intial pending request since the RT cache needs to be in sync
> with SMM cache
> +      VariableCacheContext->VariableRuntimeHobCache.PendingUpdateOffset =
> 0;
> +      VariableCacheContext->VariableRuntimeHobCache.PendingUpdateLength =
> 0;
> +      if ((mVariableModuleGlobal->VariableGlobal.HobVariableBase > 0) &&
> +          (VariableCacheContext->VariableRuntimeHobCache.Store != NULL))
> +      {
> +        VariableCache                                                     = (VARIABLE_STORE_HEADER
> *)(UINTN)mVariableModuleGlobal->VariableGlobal.HobVariableBase;
> +        VariableCacheContext->VariableRuntimeHobCache.PendingUpdateLength
> = (UINT32)((UINTN)GetEndPointer (VariableCache) - (UINTN)VariableCache);
> +        CopyGuid (&(VariableCacheContext->VariableRuntimeHobCache.Store-
> >Signature), &(VariableCache->Signature));
> +      }
> +
> +      VariableCache                                                          = (VARIABLE_STORE_HEADER
> *)(UINTN)mVariableModuleGlobal->VariableGlobal.VolatileVariableBase;
> +      VariableCacheContext-
> >VariableRuntimeVolatileCache.PendingUpdateOffset = 0;
> +      VariableCacheContext-
> >VariableRuntimeVolatileCache.PendingUpdateLength =
> (UINT32)((UINTN)GetEndPointer (VariableCache) - (UINTN)VariableCache);
> +      CopyGuid (&(VariableCacheContext->VariableRuntimeVolatileCache.Store-
> >Signature), &(VariableCache->Signature));
> +
> +      VariableCache                                                    = (VARIABLE_STORE_HEADER
> *)(UINTN)mNvVariableCache;
> +      VariableCacheContext->VariableRuntimeNvCache.PendingUpdateOffset = 0;
> +      VariableCacheContext->VariableRuntimeNvCache.PendingUpdateLength =
> (UINT32)((UINTN)GetEndPointer (VariableCache) - (UINTN)VariableCache);
> +      CopyGuid (&(VariableCacheContext->VariableRuntimeNvCache.Store-
> >Signature), &(VariableCache->Signature));
> +
> +      *(VariableCacheContext->PendingUpdate)    = TRUE;
> +      *(VariableCacheContext->ReadLock)         = FALSE;
> +      *(VariableCacheContext->HobFlushComplete) = FALSE;
> +
> +      Status = EFI_SUCCESS;
> +      break;
> +    case SMM_VARIABLE_FUNCTION_SYNC_RUNTIME_CACHE:
> +      Status = FlushPendingRuntimeVariableCacheUpdates ();
> +      break;
> +    case SMM_VARIABLE_FUNCTION_GET_RUNTIME_CACHE_INFO:
> +      if (CommBufferPayloadSize < sizeof
> (SMM_VARIABLE_COMMUNICATE_GET_RUNTIME_CACHE_INFO)) {
> +        DEBUG ((DEBUG_ERROR, "GetRuntimeCacheInfo: SMM communication
> buffer size invalid!\n"));
> +        return EFI_SUCCESS;
> +      }
> +
> +      GetRuntimeCacheInfo =
> (SMM_VARIABLE_COMMUNICATE_GET_RUNTIME_CACHE_INFO
> *)SmmVariableFunctionHeader->Data;
> +
> +      if (mVariableModuleGlobal->VariableGlobal.HobVariableBase > 0) {
> +        VariableCache                            = (VARIABLE_STORE_HEADER
> *)(UINTN)mVariableModuleGlobal->VariableGlobal.HobVariableBase;
> +        GetRuntimeCacheInfo->TotalHobStorageSize = VariableCache->Size;
> +      } else {
> +        GetRuntimeCacheInfo->TotalHobStorageSize = 0;
> +      }
> +
> +      VariableCache                                   = (VARIABLE_STORE_HEADER
> *)(UINTN)mVariableModuleGlobal->VariableGlobal.VolatileVariableBase;
> +      GetRuntimeCacheInfo->TotalVolatileStorageSize   = VariableCache->Size;
> +      VariableCache                                   = (VARIABLE_STORE_HEADER
> *)(UINTN)mNvVariableCache;
> +      GetRuntimeCacheInfo->TotalNvStorageSize         = (UINTN)VariableCache-
> >Size;
> +      GetRuntimeCacheInfo->AuthenticatedVariableUsage =
> mVariableModuleGlobal->VariableGlobal.AuthFormat;
> +
> +      Status = EFI_SUCCESS;
> +      break;
> +
> +    default:
> +      Status = EFI_UNSUPPORTED;
> +  }
> +
> +EXIT:
> +
> +  SmmVariableFunctionHeader->ReturnStatus = Status;
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  SMM END_OF_DXE protocol notification event handler.
> +
> +  @param  Protocol   Points to the protocol's unique identifier
> +  @param  Interface  Points to the interface instance
> +  @param  Handle     The handle on which the interface was installed
> +
> +  @retval EFI_SUCCESS   SmmEndOfDxeCallback runs successfully
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +SmmEndOfDxeCallback (
> +  IN CONST EFI_GUID  *Protocol,
> +  IN VOID            *Interface,
> +  IN EFI_HANDLE      Handle
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  DEBUG ((DEBUG_INFO, "[Variable]SMM_END_OF_DXE is signaled\n"));
> +  MorLockInitAtEndOfDxe ();
> +  Status = LockVariablePolicy ();
> +  ASSERT_EFI_ERROR (Status);
> +  mEndOfDxe = TRUE;
> +  VarCheckLibInitializeAtEndOfDxe (NULL);
> +  //
> +  // The initialization for variable quota.
> +  //
> +  InitializeVariableQuota ();
> +  if (PcdGetBool (PcdReclaimVariableSpaceAtEndOfDxe)) {
> +    ReclaimForOS ();
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Initializes variable write service for SMM.
> +
> +**/
> +VOID
> +VariableWriteServiceInitializeSmm (
> +  VOID
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  Status = ProtectedVariableLibWriteInit ();
> +  if (EFI_ERROR (Status) && (Status != EFI_UNSUPPORTED)) {
> +    DEBUG ((DEBUG_ERROR, "Variable protection service: write-init failed.
> Status = %r\n", Status));
> +    ASSERT_EFI_ERROR (Status);
> +    return;
> +  }
> +
> +  Status = VariableWriteServiceInitialize ();
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "Variable write service initialization failed. Status
> = %r\n", Status));
> +  }
> +
> +  //
> +  // Notify the variable wrapper driver the variable write service is ready
> +  //
> +  VariableNotifySmmWriteReady ();
> +}
> +
> +/**
> +  SMM Fault Tolerant Write protocol notification event handler.
> +
> +  Non-Volatile variable write may needs FTW protocol to reclaim when
> +  writting variable.
> +
> +  @param  Protocol   Points to the protocol's unique identifier
> +  @param  Interface  Points to the interface instance
> +  @param  Handle     The handle on which the interface was installed
> +
> +  @retval EFI_SUCCESS   SmmEventCallback runs successfully
> +  @retval EFI_NOT_FOUND The Fvb protocol for variable is not found.
> +
> + **/
> +EFI_STATUS
> +EFIAPI
> +SmmFtwNotificationEvent (
> +  IN CONST EFI_GUID  *Protocol,
> +  IN VOID            *Interface,
> +  IN EFI_HANDLE      Handle
> +  )
> +{
> +  EFI_STATUS                              Status;
> +  EFI_PHYSICAL_ADDRESS                    VariableStoreBase;
> +  EFI_SMM_FIRMWARE_VOLUME_BLOCK_PROTOCOL  *FvbProtocol;
> +  EFI_SMM_FAULT_TOLERANT_WRITE_PROTOCOL   *FtwProtocol;
> +  EFI_PHYSICAL_ADDRESS                    NvStorageVariableBase;
> +  UINTN                                   FtwMaxBlockSize;
> +  UINT32                                  NvStorageVariableSize;
> +  UINT64                                  NvStorageVariableSize64;
> +
> +  if (mVariableModuleGlobal->FvbInstance != NULL) {
> +    return EFI_SUCCESS;
> +  }
> +
> +  //
> +  // Ensure SMM FTW protocol is installed.
> +  //
> +  Status = GetFtwProtocol ((VOID **)&FtwProtocol);
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  Status = GetVariableFlashNvStorageInfo (&NvStorageVariableBase,
> &NvStorageVariableSize64);
> +  ASSERT_EFI_ERROR (Status);
> +
> +  Status = SafeUint64ToUint32 (NvStorageVariableSize64,
> &NvStorageVariableSize);
> +  // This driver currently assumes the size will be UINT32 so assert the value is
> safe for now.
> +  ASSERT_EFI_ERROR (Status);
> +
> +  ASSERT (NvStorageVariableBase != 0);
> +  VariableStoreBase = NvStorageVariableBase + mNvFvHeaderCache-
> >HeaderLength;
> +
> +  Status = FtwProtocol->GetMaxBlockSize (FtwProtocol, &FtwMaxBlockSize);
> +  if (!EFI_ERROR (Status)) {
> +    ASSERT (NvStorageVariableSize <= FtwMaxBlockSize);
> +  }
> +
> +  //
> +  // Let NonVolatileVariableBase point to flash variable store base directly after
> FTW ready.
> +  //
> +  mVariableModuleGlobal->VariableGlobal.NonVolatileVariableBase =
> VariableStoreBase;
> +
> +  //
> +  // Find the proper FVB protocol for variable.
> +  //
> +  Status = GetFvbInfoByAddress (NvStorageVariableBase, NULL, &FvbProtocol);
> +  if (EFI_ERROR (Status)) {
> +    return EFI_NOT_FOUND;
> +  }
> +
> +  mVariableModuleGlobal->FvbInstance = FvbProtocol;
> +
> +  //
> +  // Initializes variable write service after FTW was ready.
> +  //
> +  VariableWriteServiceInitializeSmm ();
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Variable Driver main entry point. The Variable driver places the 4 EFI
> +  runtime services in the EFI System Table and installs arch protocols
> +  for variable read and write services being available. It also registers
> +  a notification function for an EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE
> event.
> +
> +  @retval EFI_SUCCESS       Variable service successfully initialized.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +MmVariableServiceInitialize (
> +  VOID
> +  )
> +{
> +  EFI_STATUS                     Status;
> +  EFI_HANDLE                     VariableHandle;
> +  VOID                           *SmmFtwRegistration;
> +  VOID                           *SmmEndOfDxeRegistration;
> +  PROTECTED_VARIABLE_CONTEXT_IN  ContextIn;
> +
> +  //
> +  // Initialize protected variable service, if enabled.
> +  //
> +  ContextIn.StructSize    = sizeof (ContextIn);
> +  ContextIn.StructVersion =
> PROTECTED_VARIABLE_CONTEXT_IN_STRUCT_VERSION;
> +
> +  ContextIn.FindVariableSmm     = NULL;
> +  ContextIn.GetVariableInfo     = GetVariableInfo;
> +  ContextIn.GetNextVariableInfo = GetNextVariableInfo;
> +  ContextIn.UpdateVariableStore = VariableExLibUpdateNvVariable;
> +  ContextIn.UpdateVariable      = VariableExLibUpdateVariable;
> +
> +  ContextIn.MaxVariableSize     = (UINT32)GetMaxVariableSize ();
> +  ContextIn.VariableServiceUser = FromSmmModule;
> +
> +  Status = ProtectedVariableLibInitialize (&ContextIn);
> +  if (EFI_ERROR (Status) && (Status != EFI_UNSUPPORTED)) {
> +    ASSERT_EFI_ERROR (Status);
> +    return Status;
> +  }
> +
> +  //
> +  // Variable initialize.
> +  //
> +  Status = VariableCommonInitialize ();
> +  ASSERT_EFI_ERROR (Status);
> +
> +  //
> +  // Install the Smm Variable Protocol on a new handle.
> +  //
> +  VariableHandle = NULL;
> +  Status         = gMmst->MmInstallProtocolInterface (
> +                            &VariableHandle,
> +                            &gEfiSmmVariableProtocolGuid,
> +                            EFI_NATIVE_INTERFACE,
> +                            &gSmmVariable
> +                            );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  Status = gMmst->MmInstallProtocolInterface (
> +                    &VariableHandle,
> +                    &gEdkiiSmmVarCheckProtocolGuid,
> +                    EFI_NATIVE_INTERFACE,
> +                    &mSmmVarCheck
> +                    );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  mVariableBufferPayloadSize =  GetMaxVariableSize () +
> +                               OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_VAR_CHECK_VARIABLE_PROPERTY, Name) -
> +                               GetVariableHeaderSize (mVariableModuleGlobal-
> >VariableGlobal.AuthFormat);
> +
> +  Status = gMmst->MmAllocatePool (
> +                    EfiRuntimeServicesData,
> +                    mVariableBufferPayloadSize,
> +                    (VOID **)&mVariableBufferPayload
> +                    );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  ///
> +  /// Register SMM variable SMI handler
> +  ///
> +  VariableHandle = NULL;
> +  Status         = gMmst->MmiHandlerRegister (SmmVariableHandler,
> &gEfiSmmVariableProtocolGuid, &VariableHandle);
> +  ASSERT_EFI_ERROR (Status);
> +
> +  //
> +  // Notify the variable wrapper driver the variable service is ready
> +  //
> +  VariableNotifySmmReady ();
> +
> +  //
> +  // Register EFI_SMM_END_OF_DXE_PROTOCOL_GUID notify function.
> +  //
> +  Status = gMmst->MmRegisterProtocolNotify (
> +                    &gEfiMmEndOfDxeProtocolGuid,
> +                    SmmEndOfDxeCallback,
> +                    &SmmEndOfDxeRegistration
> +                    );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  if (!PcdGetBool (PcdEmuVariableNvModeEnable)) {
> +    //
> +    // Register FtwNotificationEvent () notify function.
> +    //
> +    Status = gMmst->MmRegisterProtocolNotify (
> +                      &gEfiSmmFaultTolerantWriteProtocolGuid,
> +                      SmmFtwNotificationEvent,
> +                      &SmmFtwRegistration
> +                      );
> +    ASSERT_EFI_ERROR (Status);
> +
> +    SmmFtwNotificationEvent (NULL, NULL, NULL);
> +  } else {
> +    //
> +    // Emulated non-volatile variable mode does not depend on FVB and FTW.
> +    //
> +    VariableWriteServiceInitializeSmm ();
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmRunt
> imeDxe.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmRunt
> imeDxe.c
> new file mode 100644
> index 000000000000..b88f75370ad8
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmRunt
> imeDxe.c
> @@ -0,0 +1,1895 @@
> +/** @file
> +  Implement all four UEFI Runtime Variable services for the nonvolatile
> +  and volatile storage space and install variable architecture protocol
> +  based on SMM variable module.
> +
> +  Caution: This module requires additional review when modified.
> +  This driver will have external input - variable data.
> +  This external input must be validated carefully to avoid security issue like
> +  buffer overflow, integer overflow.
> +
> +  RuntimeServiceGetVariable() and RuntimeServiceSetVariable() are external API
> +  to receive data buffer. The size should be checked carefully.
> +
> +  InitCommunicateBuffer() is really function to check the variable data size.
> +
> +Copyright (c) 2010 - 2022, Intel Corporation. All rights reserved.<BR>
> +Copyright (c) Microsoft Corporation.<BR>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +#include <PiDxe.h>
> +#include <Protocol/VariableWrite.h>
> +#include <Protocol/Variable.h>
> +#include <Protocol/MmCommunication2.h>
> +#include <Protocol/SmmVariable.h>
> +#include <Protocol/VariableLock.h>
> +#include <Protocol/VarCheck.h>
> +
> +#include <Library/UefiBootServicesTableLib.h>
> +#include <Library/UefiRuntimeServicesTableLib.h>
> +#include <Library/MemoryAllocationLib.h>
> +#include <Library/UefiDriverEntryPoint.h>
> +#include <Library/UefiRuntimeLib.h>
> +#include <Library/BaseMemoryLib.h>
> +#include <Library/DebugLib.h>
> +#include <Library/UefiLib.h>
> +#include <Library/BaseLib.h>
> +#include <Library/MmUnblockMemoryLib.h>
> +
> +#include <Guid/EventGroup.h>
> +#include <Guid/SmmVariableCommon.h>
> +
> +#include "PrivilegePolymorphic.h"
> +#include "Variable.h"
> +#include "VariableParsing.h"
> +
> +EFI_HANDLE                      mHandle                              = NULL;
> +EFI_SMM_VARIABLE_PROTOCOL       *mSmmVariable                        = NULL;
> +EFI_EVENT                       mVirtualAddressChangeEvent           = NULL;
> +EFI_MM_COMMUNICATION2_PROTOCOL  *mMmCommunication2                   =
> NULL;
> +UINT8                           *mVariableBuffer                     = NULL;
> +UINT8                           *mVariableBufferPhysical             = NULL;
> +VARIABLE_INFO_ENTRY             *mVariableInfo                       = NULL;
> +VARIABLE_STORE_HEADER           *mVariableRuntimeHobCacheBuffer      =
> NULL;
> +VARIABLE_STORE_HEADER           *mVariableRuntimeNvCacheBuffer       = NULL;
> +VARIABLE_STORE_HEADER           *mVariableRuntimeVolatileCacheBuffer =
> NULL;
> +VARIABLE_STORE_HEADER           *mNvVariableCache                    = NULL;
> +VARIABLE_MODULE_GLOBAL          *mVariableModuleGlobal               = NULL;
> +UINTN                           mVariableBufferSize;
> +UINTN                           mVariableRuntimeHobCacheBufferSize;
> +UINTN                           mVariableRuntimeNvCacheBufferSize;
> +UINTN                           mVariableRuntimeVolatileCacheBufferSize;
> +UINTN                           mVariableBufferPayloadSize;
> +BOOLEAN                         mVariableRuntimeCachePendingUpdate;
> +BOOLEAN                         mVariableRuntimeCacheReadLock;
> +BOOLEAN                         mVariableAuthFormat;
> +BOOLEAN                         mHobFlushComplete;
> +EFI_LOCK                        mVariableServicesLock;
> +EDKII_VARIABLE_LOCK_PROTOCOL    mVariableLock;
> +EDKII_VAR_CHECK_PROTOCOL        mVarCheck;
> +
> +/**
> +  The logic to initialize the VariablePolicy engine is in its own file.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariablePolicySmmDxeMain (
> +  IN    EFI_HANDLE        ImageHandle,
> +  IN    EFI_SYSTEM_TABLE  *SystemTable
> +  );
> +
> +/**
> +  Some Secure Boot Policy Variable may update following other variable
> changes(SecureBoot follows PK change, etc).
> +  Record their initial State when variable write service is ready.
> +
> +**/
> +VOID
> +EFIAPI
> +RecordSecureBootPolicyVarData (
> +  VOID
> +  );
> +
> +/**
> +  Acquires lock only at boot time. Simply returns at runtime.
> +
> +  This is a temperary function that will be removed when
> +  EfiAcquireLock() in UefiLib can handle the call in UEFI
> +  Runtimer driver in RT phase.
> +  It calls EfiAcquireLock() at boot time, and simply returns
> +  at runtime.
> +
> +  @param  Lock         A pointer to the lock to acquire.
> +
> +**/
> +VOID
> +AcquireLockOnlyAtBootTime (
> +  IN EFI_LOCK  *Lock
> +  )
> +{
> +  if (!EfiAtRuntime ()) {
> +    EfiAcquireLock (Lock);
> +  }
> +}
> +
> +/**
> +  Releases lock only at boot time. Simply returns at runtime.
> +
> +  This is a temperary function which will be removed when
> +  EfiReleaseLock() in UefiLib can handle the call in UEFI
> +  Runtimer driver in RT phase.
> +  It calls EfiReleaseLock() at boot time and simply returns
> +  at runtime.
> +
> +  @param  Lock         A pointer to the lock to release.
> +
> +**/
> +VOID
> +ReleaseLockOnlyAtBootTime (
> +  IN EFI_LOCK  *Lock
> +  )
> +{
> +  if (!EfiAtRuntime ()) {
> +    EfiReleaseLock (Lock);
> +  }
> +}
> +
> +/**
> +  Return TRUE if ExitBootServices () has been called.
> +
> +  @retval TRUE If ExitBootServices () has been called. FALSE if ExitBootServices
> () has not been called.
> +**/
> +BOOLEAN
> +AtRuntime (
> +  VOID
> +  )
> +{
> +  return EfiAtRuntime ();
> +}
> +
> +/**
> +  Initialize the variable cache buffer as an empty variable store.
> +
> +  @param[out]     VariableCacheBuffer     A pointer to pointer of a cache
> variable store.
> +  @param[in,out]  TotalVariableCacheSize  On input, the minimum size needed
> for the UEFI variable store cache
> +                                          buffer that is allocated. On output, the actual size of the
> buffer allocated.
> +                                          If TotalVariableCacheSize is zero, a buffer will not be
> allocated and the
> +                                          function will return with EFI_SUCCESS.
> +
> +  @retval EFI_SUCCESS             The variable cache was allocated and initialized
> successfully.
> +  @retval EFI_INVALID_PARAMETER   A given pointer is NULL or an invalid
> variable store size was specified.
> +  @retval EFI_OUT_OF_RESOURCES    Insufficient resources are available to
> allocate the variable store cache buffer.
> +
> +**/
> +EFI_STATUS
> +InitVariableCache (
> +  OUT    VARIABLE_STORE_HEADER  **VariableCacheBuffer,
> +  IN OUT UINTN                  *TotalVariableCacheSize
> +  )
> +{
> +  VARIABLE_STORE_HEADER  *VariableCacheStorePtr;
> +  EFI_STATUS             Status;
> +
> +  if (TotalVariableCacheSize == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (*TotalVariableCacheSize == 0) {
> +    return EFI_SUCCESS;
> +  }
> +
> +  if ((VariableCacheBuffer == NULL) || (*TotalVariableCacheSize < sizeof
> (VARIABLE_STORE_HEADER))) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  *TotalVariableCacheSize = ALIGN_VALUE (*TotalVariableCacheSize, sizeof
> (UINT32));
> +
> +  //
> +  // Allocate NV Storage Cache and initialize it to all 1's (like an erased FV)
> +  //
> +  *VariableCacheBuffer =  (VARIABLE_STORE_HEADER *)AllocateRuntimePages
> (
> +                                                     EFI_SIZE_TO_PAGES (*TotalVariableCacheSize)
> +                                                     );
> +  if (*VariableCacheBuffer == NULL) {
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +
> +  //
> +  // Request to unblock the newly allocated cache region to be accessible from
> inside MM
> +  //
> +  Status = MmUnblockMemoryRequest (
> +             (EFI_PHYSICAL_ADDRESS)(UINTN)*VariableCacheBuffer,
> +             EFI_SIZE_TO_PAGES (*TotalVariableCacheSize)
> +             );
> +  if ((Status != EFI_UNSUPPORTED) && EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  VariableCacheStorePtr = *VariableCacheBuffer;
> +  SetMem32 ((VOID *)VariableCacheStorePtr, *TotalVariableCacheSize,
> (UINT32)0xFFFFFFFF);
> +
> +  ZeroMem ((VOID *)VariableCacheStorePtr, sizeof
> (VARIABLE_STORE_HEADER));
> +  VariableCacheStorePtr->Size   = (UINT32)*TotalVariableCacheSize;
> +  VariableCacheStorePtr->Format = VARIABLE_STORE_FORMATTED;
> +  VariableCacheStorePtr->State  = VARIABLE_STORE_HEALTHY;
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Initialize the communicate buffer using DataSize and Function.
> +
> +  The communicate size is: SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE +
> +  DataSize.
> +
> +  Caution: This function may receive untrusted input.
> +  The data size external input, so this function will validate it carefully to avoid
> buffer overflow.
> +
> +  @param[out]      DataPtr          Points to the data in the communicate buffer.
> +  @param[in]       DataSize         The data size to send to SMM.
> +  @param[in]       Function         The function number to initialize the
> communicate header.
> +
> +  @retval EFI_INVALID_PARAMETER     The data size is too big.
> +  @retval EFI_SUCCESS               Find the specified variable.
> +
> +**/
> +EFI_STATUS
> +InitCommunicateBuffer (
> +  OUT     VOID   **DataPtr OPTIONAL,
> +  IN      UINTN  DataSize,
> +  IN      UINTN  Function
> +  )
> +{
> +  EFI_MM_COMMUNICATE_HEADER        *SmmCommunicateHeader;
> +  SMM_VARIABLE_COMMUNICATE_HEADER  *SmmVariableFunctionHeader;
> +
> +  if (DataSize + SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE > mVariableBufferSize) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  SmmCommunicateHeader = (EFI_MM_COMMUNICATE_HEADER
> *)mVariableBuffer;
> +  CopyGuid (&SmmCommunicateHeader->HeaderGuid,
> &gEfiSmmVariableProtocolGuid);
> +  SmmCommunicateHeader->MessageLength = DataSize +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE;
> +
> +  SmmVariableFunctionHeader           =
> (SMM_VARIABLE_COMMUNICATE_HEADER *)SmmCommunicateHeader->Data;
> +  SmmVariableFunctionHeader->Function = Function;
> +  if (DataPtr != NULL) {
> +    *DataPtr = SmmVariableFunctionHeader->Data;
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Send the data in communicate buffer to SMM.
> +
> +  @param[in]   DataSize               This size of the function header and the data.
> +
> +  @retval      EFI_SUCCESS            Success is returned from the functin in SMM.
> +  @retval      Others                 Failure is returned from the function in SMM.
> +
> +**/
> +EFI_STATUS
> +SendCommunicateBuffer (
> +  IN      UINTN  DataSize
> +  )
> +{
> +  EFI_STATUS                       Status;
> +  UINTN                            CommSize;
> +  EFI_MM_COMMUNICATE_HEADER        *SmmCommunicateHeader;
> +  SMM_VARIABLE_COMMUNICATE_HEADER  *SmmVariableFunctionHeader;
> +
> +  CommSize = DataSize + SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE;
> +  Status   = mMmCommunication2->Communicate (
> +                                  mMmCommunication2,
> +                                  mVariableBufferPhysical,
> +                                  mVariableBuffer,
> +                                  &CommSize
> +                                  );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  SmmCommunicateHeader      = (EFI_MM_COMMUNICATE_HEADER
> *)mVariableBuffer;
> +  SmmVariableFunctionHeader = (SMM_VARIABLE_COMMUNICATE_HEADER
> *)SmmCommunicateHeader->Data;
> +  return SmmVariableFunctionHeader->ReturnStatus;
> +}
> +
> +/**
> +  Mark a variable that will become read-only after leaving the DXE phase of
> execution.
> +
> +  @param[in] This          The VARIABLE_LOCK_PROTOCOL instance.
> +  @param[in] VariableName  A pointer to the variable name that will be made
> read-only subsequently.
> +  @param[in] VendorGuid    A pointer to the vendor GUID that will be made
> read-only subsequently.
> +
> +  @retval EFI_SUCCESS           The variable specified by the VariableName and
> the VendorGuid was marked
> +                                as pending to be read-only.
> +  @retval EFI_INVALID_PARAMETER VariableName or VendorGuid is NULL.
> +                                Or VariableName is an empty string.
> +  @retval EFI_ACCESS_DENIED     EFI_END_OF_DXE_EVENT_GROUP_GUID or
> EFI_EVENT_GROUP_READY_TO_BOOT has
> +                                already been signaled.
> +  @retval EFI_OUT_OF_RESOURCES  There is not enough resource to hold the
> lock request.
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableLockRequestToLock (
> +  IN CONST EDKII_VARIABLE_LOCK_PROTOCOL  *This,
> +  IN       CHAR16                        *VariableName,
> +  IN       EFI_GUID                      *VendorGuid
> +  )
> +{
> +  EFI_STATUS                              Status;
> +  UINTN                                   VariableNameSize;
> +  UINTN                                   PayloadSize;
> +  SMM_VARIABLE_COMMUNICATE_LOCK_VARIABLE  *VariableToLock;
> +
> +  if ((VariableName == NULL) || (VariableName[0] == 0) || (VendorGuid ==
> NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  VariableNameSize = StrSize (VariableName);
> +  VariableToLock   = NULL;
> +
> +  //
> +  // If VariableName exceeds SMM payload limit. Return failure
> +  //
> +  if (VariableNameSize > mVariableBufferPayloadSize - OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_LOCK_VARIABLE, Name)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mVariableServicesLock);
> +
> +  //
> +  // Init the communicate buffer. The buffer data size is:
> +  // SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize.
> +  //
> +  PayloadSize = OFFSET_OF (SMM_VARIABLE_COMMUNICATE_LOCK_VARIABLE,
> Name) + VariableNameSize;
> +  Status      = InitCommunicateBuffer ((VOID **)&VariableToLock, PayloadSize,
> SMM_VARIABLE_FUNCTION_LOCK_VARIABLE);
> +  if (EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +  ASSERT (VariableToLock != NULL);
> +
> +  CopyGuid (&VariableToLock->Guid, VendorGuid);
> +  VariableToLock->NameSize = VariableNameSize;
> +  CopyMem (VariableToLock->Name, VariableName, VariableToLock-
> >NameSize);
> +
> +  //
> +  // Send data to SMM.
> +  //
> +  Status = SendCommunicateBuffer (PayloadSize);
> +
> +Done:
> +  ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
> +  return Status;
> +}
> +
> +/**
> +  Register SetVariable check handler.
> +
> +  @param[in] Handler            Pointer to check handler.
> +
> +  @retval EFI_SUCCESS           The SetVariable check handler was registered
> successfully.
> +  @retval EFI_INVALID_PARAMETER Handler is NULL.
> +  @retval EFI_ACCESS_DENIED     EFI_END_OF_DXE_EVENT_GROUP_GUID or
> EFI_EVENT_GROUP_READY_TO_BOOT has
> +                                already been signaled.
> +  @retval EFI_OUT_OF_RESOURCES  There is not enough resource for the
> SetVariable check handler register request.
> +  @retval EFI_UNSUPPORTED       This interface is not implemented.
> +                                For example, it is unsupported in VarCheck protocol if both
> VarCheck and SmmVarCheck protocols are present.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VarCheckRegisterSetVariableCheckHandler (
> +  IN VAR_CHECK_SET_VARIABLE_CHECK_HANDLER  Handler
> +  )
> +{
> +  return EFI_UNSUPPORTED;
> +}
> +
> +/**
> +  Variable property set.
> +
> +  @param[in] Name               Pointer to the variable name.
> +  @param[in] Guid               Pointer to the vendor GUID.
> +  @param[in] VariableProperty   Pointer to the input variable property.
> +
> +  @retval EFI_SUCCESS           The property of variable specified by the Name
> and Guid was set successfully.
> +  @retval EFI_INVALID_PARAMETER Name, Guid or VariableProperty is NULL,
> or Name is an empty string,
> +                                or the fields of VariableProperty are not valid.
> +  @retval EFI_ACCESS_DENIED     EFI_END_OF_DXE_EVENT_GROUP_GUID or
> EFI_EVENT_GROUP_READY_TO_BOOT has
> +                                already been signaled.
> +  @retval EFI_OUT_OF_RESOURCES  There is not enough resource for the
> variable property set request.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VarCheckVariablePropertySet (
> +  IN CHAR16                       *Name,
> +  IN EFI_GUID                     *Guid,
> +  IN VAR_CHECK_VARIABLE_PROPERTY  *VariableProperty
> +  )
> +{
> +  EFI_STATUS                                            Status;
> +  UINTN                                                 VariableNameSize;
> +  UINTN                                                 PayloadSize;
> +  SMM_VARIABLE_COMMUNICATE_VAR_CHECK_VARIABLE_PROPERTY
> *CommVariableProperty;
> +
> +  if ((Name == NULL) || (Name[0] == 0) || (Guid == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (VariableProperty == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (VariableProperty->Revision !=
> VAR_CHECK_VARIABLE_PROPERTY_REVISION) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  VariableNameSize     = StrSize (Name);
> +  CommVariableProperty = NULL;
> +
> +  //
> +  // If VariableName exceeds SMM payload limit. Return failure
> +  //
> +  if (VariableNameSize > mVariableBufferPayloadSize - OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_VAR_CHECK_VARIABLE_PROPERTY, Name))
> {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mVariableServicesLock);
> +
> +  //
> +  // Init the communicate buffer. The buffer data size is:
> +  // SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize.
> +  //
> +  PayloadSize = OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_VAR_CHECK_VARIABLE_PROPERTY, Name) +
> VariableNameSize;
> +  Status      = InitCommunicateBuffer ((VOID **)&CommVariableProperty,
> PayloadSize,
> SMM_VARIABLE_FUNCTION_VAR_CHECK_VARIABLE_PROPERTY_SET);
> +  if (EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +  ASSERT (CommVariableProperty != NULL);
> +
> +  CopyGuid (&CommVariableProperty->Guid, Guid);
> +  CopyMem (&CommVariableProperty->VariableProperty, VariableProperty,
> sizeof (*VariableProperty));
> +  CommVariableProperty->NameSize = VariableNameSize;
> +  CopyMem (CommVariableProperty->Name, Name, CommVariableProperty-
> >NameSize);
> +
> +  //
> +  // Send data to SMM.
> +  //
> +  Status = SendCommunicateBuffer (PayloadSize);
> +
> +Done:
> +  ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
> +  return Status;
> +}
> +
> +/**
> +  Variable property get.
> +
> +  @param[in]  Name              Pointer to the variable name.
> +  @param[in]  Guid              Pointer to the vendor GUID.
> +  @param[out] VariableProperty  Pointer to the output variable property.
> +
> +  @retval EFI_SUCCESS           The property of variable specified by the Name
> and Guid was got successfully.
> +  @retval EFI_INVALID_PARAMETER Name, Guid or VariableProperty is NULL,
> or Name is an empty string.
> +  @retval EFI_NOT_FOUND         The property of variable specified by the Name
> and Guid was not found.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VarCheckVariablePropertyGet (
> +  IN CHAR16                        *Name,
> +  IN EFI_GUID                      *Guid,
> +  OUT VAR_CHECK_VARIABLE_PROPERTY  *VariableProperty
> +  )
> +{
> +  EFI_STATUS                                            Status;
> +  UINTN                                                 VariableNameSize;
> +  UINTN                                                 PayloadSize;
> +  SMM_VARIABLE_COMMUNICATE_VAR_CHECK_VARIABLE_PROPERTY
> *CommVariableProperty;
> +
> +  if ((Name == NULL) || (Name[0] == 0) || (Guid == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (VariableProperty == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  VariableNameSize     = StrSize (Name);
> +  CommVariableProperty = NULL;
> +
> +  //
> +  // If VariableName exceeds SMM payload limit. Return failure
> +  //
> +  if (VariableNameSize > mVariableBufferPayloadSize - OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_VAR_CHECK_VARIABLE_PROPERTY, Name))
> {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mVariableServicesLock);
> +
> +  //
> +  // Init the communicate buffer. The buffer data size is:
> +  // SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize.
> +  //
> +  PayloadSize = OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_VAR_CHECK_VARIABLE_PROPERTY, Name) +
> VariableNameSize;
> +  Status      = InitCommunicateBuffer ((VOID **)&CommVariableProperty,
> PayloadSize,
> SMM_VARIABLE_FUNCTION_VAR_CHECK_VARIABLE_PROPERTY_GET);
> +  if (EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +  ASSERT (CommVariableProperty != NULL);
> +
> +  CopyGuid (&CommVariableProperty->Guid, Guid);
> +  CommVariableProperty->NameSize = VariableNameSize;
> +  CopyMem (CommVariableProperty->Name, Name, CommVariableProperty-
> >NameSize);
> +
> +  //
> +  // Send data to SMM.
> +  //
> +  Status = SendCommunicateBuffer (PayloadSize);
> +  if (Status == EFI_SUCCESS) {
> +    CopyMem (VariableProperty, &CommVariableProperty->VariableProperty,
> sizeof (*VariableProperty));
> +  }
> +
> +Done:
> +  ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
> +  return Status;
> +}
> +
> +/**
> +  Signals SMM to synchronize any pending variable updates with the runtime
> cache(s).
> +
> +**/
> +VOID
> +SyncRuntimeCache (
> +  VOID
> +  )
> +{
> +  //
> +  // Init the communicate buffer. The buffer data size is:
> +  // SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE.
> +  //
> +  InitCommunicateBuffer (NULL, 0,
> SMM_VARIABLE_FUNCTION_SYNC_RUNTIME_CACHE);
> +
> +  //
> +  // Send data to SMM.
> +  //
> +  SendCommunicateBuffer (0);
> +}
> +
> +/**
> +  Check whether a SMI must be triggered to retrieve pending cache updates.
> +
> +  If the variable HOB was finished being flushed since the last check for a
> runtime cache update, this function
> +  will prevent the HOB cache from being used for future runtime cache hits.
> +
> +**/
> +VOID
> +CheckForRuntimeCacheSync (
> +  VOID
> +  )
> +{
> +  if (mVariableRuntimeCachePendingUpdate) {
> +    SyncRuntimeCache ();
> +  }
> +
> +  ASSERT (!mVariableRuntimeCachePendingUpdate);
> +
> +  //
> +  // The HOB variable data may have finished being flushed in the runtime cache
> sync update
> +  //
> +  if (mHobFlushComplete && (mVariableRuntimeHobCacheBuffer != NULL)) {
> +    if (!EfiAtRuntime ()) {
> +      FreePages (mVariableRuntimeHobCacheBuffer, EFI_SIZE_TO_PAGES
> (mVariableRuntimeHobCacheBufferSize));
> +    }
> +
> +    mVariableRuntimeHobCacheBuffer = NULL;
> +  }
> +}
> +
> +/**
> +  Finds the given variable in a runtime cache variable store.
> +
> +  Caution: This function may receive untrusted input.
> +  The data size is external input, so this function will validate it carefully to
> avoid buffer overflow.
> +
> +  @param[in]      VariableName       Name of Variable to be found.
> +  @param[in]      VendorGuid         Variable vendor GUID.
> +  @param[out]     Attributes         Attribute value of the variable found.
> +  @param[in, out] DataSize           Size of Data found. If size is less than the
> +                                     data, this value contains the required size.
> +  @param[out]     Data               Data pointer.
> +
> +  @retval EFI_SUCCESS                Found the specified variable.
> +  @retval EFI_INVALID_PARAMETER      Invalid parameter.
> +  @retval EFI_NOT_FOUND              The specified variable could not be found.
> +
> +**/
> +EFI_STATUS
> +FindVariableInRuntimeCache (
> +  IN      CHAR16    *VariableName,
> +  IN      EFI_GUID  *VendorGuid,
> +  OUT     UINT32    *Attributes OPTIONAL,
> +  IN OUT  UINTN     *DataSize,
> +  OUT     VOID      *Data OPTIONAL
> +  )
> +{
> +  EFI_STATUS              Status;
> +  VARIABLE_POINTER_TRACK  RtPtrTrack;
> +  VARIABLE_STORE_TYPE     StoreType;
> +  VARIABLE_STORE_HEADER   *VariableStoreList[VariableStoreTypeMax];
> +
> +  Status = EFI_NOT_FOUND;
> +
> +  if ((VariableName == NULL) || (VendorGuid == NULL) || (DataSize == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  ZeroMem (&RtPtrTrack, sizeof (RtPtrTrack));
> +
> +  //
> +  // The UEFI specification restricts Runtime Services callers from invoking the
> same or certain other Runtime Service
> +  // functions prior to completion and return from a previous Runtime Service
> call. These restrictions prevent
> +  // a GetVariable () or GetNextVariable () call from being issued until a prior call
> has returned. The runtime
> +  // cache read lock should always be free when entering this function.
> +  //
> +  ASSERT (!mVariableRuntimeCacheReadLock);
> +
> +  mVariableRuntimeCacheReadLock = TRUE;
> +  CheckForRuntimeCacheSync ();
> +
> +  if (!mVariableRuntimeCachePendingUpdate) {
> +    //
> +    // 0: Volatile, 1: HOB, 2: Non-Volatile.
> +    // The index and attributes mapping must be kept in this order as
> FindVariable
> +    // makes use of this mapping to implement search algorithm.
> +    //
> +    VariableStoreList[VariableStoreTypeVolatile] =
> mVariableRuntimeVolatileCacheBuffer;
> +    VariableStoreList[VariableStoreTypeHob]      =
> mVariableRuntimeHobCacheBuffer;
> +    VariableStoreList[VariableStoreTypeNv]       =
> mVariableRuntimeNvCacheBuffer;
> +
> +    for (StoreType = (VARIABLE_STORE_TYPE)0; StoreType <
> VariableStoreTypeMax; StoreType++) {
> +      if (VariableStoreList[StoreType] == NULL) {
> +        continue;
> +      }
> +
> +      RtPtrTrack.StartPtr = GetStartPointer (VariableStoreList[StoreType]);
> +      RtPtrTrack.EndPtr   = GetEndPointer (VariableStoreList[StoreType]);
> +      RtPtrTrack.Volatile = (BOOLEAN)(StoreType == VariableStoreTypeVolatile);
> +
> +      Status = FindVariableEx (VariableName, VendorGuid, FALSE, &RtPtrTrack,
> mVariableAuthFormat);
> +      if (!EFI_ERROR (Status)) {
> +        break;
> +      }
> +    }
> +
> +    if (!EFI_ERROR (Status)) {
> +      //
> +      // Get data size
> +      //
> +      if (!RtPtrTrack.Volatile) {
> +        //
> +        // Currently only non-volatile variable needs protection.
> +        //
> +        Status = ProtectedVariableLibGetByBuffer (RtPtrTrack.CurrPtr, Data,
> (UINT32 *)DataSize, mVariableAuthFormat);
> +      }
> +
> +      if (RtPtrTrack.Volatile || (Status == EFI_UNSUPPORTED)) {
> +        Status = GetVariableData (RtPtrTrack.CurrPtr, Data, (UINT32 *)DataSize,
> mVariableAuthFormat);
> +      }
> +
> +      if (!EFI_ERROR (Status)) {
> +        UpdateVariableInfo (VariableName, VendorGuid, RtPtrTrack.Volatile,
> TRUE, FALSE, FALSE, FALSE, &mVariableInfo);
> +      }
> +    }
> +  }
> +
> +  if ((Status == EFI_SUCCESS) || (Status == EFI_BUFFER_TOO_SMALL)) {
> +    if ((Attributes != NULL) && (RtPtrTrack.CurrPtr != NULL)) {
> +      *Attributes = RtPtrTrack.CurrPtr->Attributes;
> +    }
> +  }
> +
> +  mVariableRuntimeCacheReadLock = FALSE;
> +
> +  return Status;
> +}
> +
> +/**
> +  Finds the given variable in a variable store in SMM.
> +
> +  Caution: This function may receive untrusted input.
> +  The data size is external input, so this function will validate it carefully to
> avoid buffer overflow.
> +
> +  @param[in]      VariableName       Name of Variable to be found.
> +  @param[in]      VendorGuid         Variable vendor GUID.
> +  @param[out]     Attributes         Attribute value of the variable found.
> +  @param[in, out] DataSize           Size of Data found. If size is less than the
> +                                     data, this value contains the required size.
> +  @param[out]     Data               Data pointer.
> +
> +  @retval EFI_SUCCESS                Found the specified variable.
> +  @retval EFI_INVALID_PARAMETER      Invalid parameter.
> +  @retval EFI_NOT_FOUND              The specified variable could not be found.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +FindVariableInSmm (
> +  IN      CHAR16    *VariableName,
> +  IN      EFI_GUID  *VendorGuid,
> +  OUT     UINT32    *Attributes OPTIONAL,
> +  IN OUT  UINTN     *DataSize,
> +  OUT     VOID      *Data OPTIONAL
> +  )
> +{
> +  EFI_STATUS                                Status;
> +  UINTN                                     PayloadSize;
> +  SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE  *SmmVariableHeader;
> +  UINTN                                     TempDataSize;
> +  UINTN                                     VariableNameSize;
> +
> +  if ((VariableName == NULL) || (VendorGuid == NULL) || (DataSize == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  TempDataSize      = *DataSize;
> +  VariableNameSize  = StrSize (VariableName);
> +  SmmVariableHeader = NULL;
> +
> +  //
> +  // If VariableName exceeds SMM payload limit. Return failure
> +  //
> +  if (VariableNameSize > mVariableBufferPayloadSize - OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  //
> +  // Init the communicate buffer. The buffer data size is:
> +  // SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize.
> +  //
> +  if (TempDataSize > mVariableBufferPayloadSize - OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) -
> VariableNameSize) {
> +    //
> +    // If output data buffer exceed SMM payload limit. Trim output buffer to
> SMM payload size
> +    //
> +    TempDataSize = mVariableBufferPayloadSize - OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) -
> VariableNameSize;
> +  }
> +
> +  PayloadSize = OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) +
> VariableNameSize + TempDataSize;
> +
> +  Status = InitCommunicateBuffer ((VOID **)&SmmVariableHeader, PayloadSize,
> SMM_VARIABLE_FUNCTION_GET_VARIABLE);
> +  if (EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +  ASSERT (SmmVariableHeader != NULL);
> +
> +  CopyGuid (&SmmVariableHeader->Guid, VendorGuid);
> +  SmmVariableHeader->DataSize = TempDataSize;
> +  SmmVariableHeader->NameSize = VariableNameSize;
> +  if (Attributes == NULL) {
> +    SmmVariableHeader->Attributes = 0;
> +  } else {
> +    SmmVariableHeader->Attributes = *Attributes;
> +  }
> +
> +  CopyMem (SmmVariableHeader->Name, VariableName, SmmVariableHeader-
> >NameSize);
> +
> +  //
> +  // Send data to SMM.
> +  //
> +  Status = SendCommunicateBuffer (PayloadSize);
> +
> +  //
> +  // Get data from SMM.
> +  //
> +  if ((Status == EFI_SUCCESS) || (Status == EFI_BUFFER_TOO_SMALL)) {
> +    //
> +    // SMM CommBuffer DataSize can be a trimed value
> +    // Only update DataSize when needed
> +    //
> +    *DataSize = SmmVariableHeader->DataSize;
> +  }
> +
> +  if (Attributes != NULL) {
> +    *Attributes = SmmVariableHeader->Attributes;
> +  }
> +
> +  if (EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +  if (Data != NULL) {
> +    CopyMem (Data, (UINT8 *)SmmVariableHeader->Name +
> SmmVariableHeader->NameSize, SmmVariableHeader->DataSize);
> +  } else {
> +    Status = EFI_INVALID_PARAMETER;
> +  }
> +
> +Done:
> +  return Status;
> +}
> +
> +/**
> +  This code finds variable in storage blocks (Volatile or Non-Volatile).
> +
> +  Caution: This function may receive untrusted input.
> +  The data size is external input, so this function will validate it carefully to
> avoid buffer overflow.
> +
> +  @param[in]      VariableName       Name of Variable to be found.
> +  @param[in]      VendorGuid         Variable vendor GUID.
> +  @param[out]     Attributes         Attribute value of the variable found.
> +  @param[in, out] DataSize           Size of Data found. If size is less than the
> +                                     data, this value contains the required size.
> +  @param[out]     Data               Data pointer.
> +
> +  @retval EFI_INVALID_PARAMETER      Invalid parameter.
> +  @retval EFI_SUCCESS                Find the specified variable.
> +  @retval EFI_NOT_FOUND              Not found.
> +  @retval EFI_BUFFER_TO_SMALL        DataSize is too small for the result.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +RuntimeServiceGetVariable (
> +  IN      CHAR16    *VariableName,
> +  IN      EFI_GUID  *VendorGuid,
> +  OUT     UINT32    *Attributes OPTIONAL,
> +  IN OUT  UINTN     *DataSize,
> +  OUT     VOID      *Data
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  if ((VariableName == NULL) || (VendorGuid == NULL) || (DataSize == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (VariableName[0] == 0) {
> +    return EFI_NOT_FOUND;
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mVariableServicesLock);
> +  if (FeaturePcdGet (PcdEnableVariableRuntimeCache)) {
> +    Status = FindVariableInRuntimeCache (VariableName, VendorGuid, Attributes,
> DataSize, Data);
> +  } else {
> +    Status = FindVariableInSmm (VariableName, VendorGuid, Attributes, DataSize,
> Data);
> +  }
> +
> +  ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
> +
> +  return Status;
> +}
> +
> +/**
> +  Finds the next available variable in a runtime cache variable store.
> +
> +  @param[in, out] VariableNameSize   Size of the variable name.
> +  @param[in, out] VariableName       Pointer to variable name.
> +  @param[in, out] VendorGuid         Variable Vendor Guid.
> +
> +  @retval EFI_INVALID_PARAMETER      Invalid parameter.
> +  @retval EFI_SUCCESS                Find the specified variable.
> +  @retval EFI_NOT_FOUND              Not found.
> +  @retval EFI_BUFFER_TO_SMALL        DataSize is too small for the result.
> +
> +**/
> +EFI_STATUS
> +GetNextVariableNameInRuntimeCache (
> +  IN OUT  UINTN     *VariableNameSize,
> +  IN OUT  CHAR16    *VariableName,
> +  IN OUT  EFI_GUID  *VendorGuid
> +  )
> +{
> +  EFI_STATUS             Status;
> +  UINTN                  VarNameSize;
> +  VARIABLE_HEADER        *VariablePtr;
> +  VARIABLE_STORE_HEADER  *VariableStoreHeader[VariableStoreTypeMax];
> +
> +  Status = EFI_NOT_FOUND;
> +
> +  //
> +  // The UEFI specification restricts Runtime Services callers from invoking the
> same or certain other Runtime Service
> +  // functions prior to completion and return from a previous Runtime Service
> call. These restrictions prevent
> +  // a GetVariable () or GetNextVariable () call from being issued until a prior call
> has returned. The runtime
> +  // cache read lock should always be free when entering this function.
> +  //
> +  ASSERT (!mVariableRuntimeCacheReadLock);
> +
> +  CheckForRuntimeCacheSync ();
> +
> +  mVariableRuntimeCacheReadLock = TRUE;
> +  if (!mVariableRuntimeCachePendingUpdate) {
> +    //
> +    // 0: Volatile, 1: HOB, 2: Non-Volatile.
> +    // The index and attributes mapping must be kept in this order as
> FindVariable
> +    // makes use of this mapping to implement search algorithm.
> +    //
> +    VariableStoreHeader[VariableStoreTypeVolatile] =
> mVariableRuntimeVolatileCacheBuffer;
> +    VariableStoreHeader[VariableStoreTypeHob]      =
> mVariableRuntimeHobCacheBuffer;
> +    VariableStoreHeader[VariableStoreTypeNv]       =
> mVariableRuntimeNvCacheBuffer;
> +
> +    Status =  VariableServiceGetNextVariableInternal (
> +                VariableName,
> +                VendorGuid,
> +                VariableStoreHeader,
> +                &VariablePtr,
> +                mVariableAuthFormat
> +                );
> +    if (!EFI_ERROR (Status)) {
> +      VarNameSize = NameSizeOfVariable (VariablePtr, mVariableAuthFormat);
> +      ASSERT (VarNameSize != 0);
> +      if (VarNameSize <= *VariableNameSize) {
> +        CopyMem (VariableName, GetVariableNamePtr (VariablePtr,
> mVariableAuthFormat), VarNameSize);
> +        CopyMem (VendorGuid, GetVendorGuidPtr (VariablePtr,
> mVariableAuthFormat), sizeof (EFI_GUID));
> +        Status = EFI_SUCCESS;
> +      } else {
> +        Status = EFI_BUFFER_TOO_SMALL;
> +      }
> +
> +      *VariableNameSize = VarNameSize;
> +    }
> +  }
> +
> +  mVariableRuntimeCacheReadLock = FALSE;
> +
> +  return Status;
> +}
> +
> +/**
> +  Finds the next available variable in a SMM variable store.
> +
> +  @param[in, out] VariableNameSize   Size of the variable name.
> +  @param[in, out] VariableName       Pointer to variable name.
> +  @param[in, out] VendorGuid         Variable Vendor Guid.
> +
> +  @retval EFI_INVALID_PARAMETER      Invalid parameter.
> +  @retval EFI_SUCCESS                Find the specified variable.
> +  @retval EFI_NOT_FOUND              Not found.
> +  @retval EFI_BUFFER_TO_SMALL        DataSize is too small for the result.
> +
> +**/
> +EFI_STATUS
> +GetNextVariableNameInSmm (
> +  IN OUT  UINTN     *VariableNameSize,
> +  IN OUT  CHAR16    *VariableName,
> +  IN OUT  EFI_GUID  *VendorGuid
> +  )
> +{
> +  EFI_STATUS                                       Status;
> +  UINTN                                            PayloadSize;
> +  SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME
> *SmmGetNextVariableName;
> +  UINTN                                            OutVariableNameSize;
> +  UINTN                                            InVariableNameSize;
> +
> +  OutVariableNameSize    = *VariableNameSize;
> +  InVariableNameSize     = StrSize (VariableName);
> +  SmmGetNextVariableName = NULL;
> +
> +  //
> +  // If input string exceeds SMM payload limit. Return failure
> +  //
> +  if (InVariableNameSize > mVariableBufferPayloadSize - OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  //
> +  // Init the communicate buffer. The buffer data size is:
> +  // SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize.
> +  //
> +  if (OutVariableNameSize > mVariableBufferPayloadSize - OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name)) {
> +    //
> +    // If output buffer exceed SMM payload limit. Trim output buffer to SMM
> payload size
> +    //
> +    OutVariableNameSize = mVariableBufferPayloadSize - OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name);
> +  }
> +
> +  //
> +  // Payload should be Guid + NameSize + MAX of Input & Output buffer
> +  //
> +  PayloadSize = OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name) + MAX
> (OutVariableNameSize, InVariableNameSize);
> +
> +  Status = InitCommunicateBuffer ((VOID **)&SmmGetNextVariableName,
> PayloadSize, SMM_VARIABLE_FUNCTION_GET_NEXT_VARIABLE_NAME);
> +  if (EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +  ASSERT (SmmGetNextVariableName != NULL);
> +
> +  //
> +  // SMM comm buffer->NameSize is buffer size for return string
> +  //
> +  SmmGetNextVariableName->NameSize = OutVariableNameSize;
> +
> +  CopyGuid (&SmmGetNextVariableName->Guid, VendorGuid);
> +  //
> +  // Copy whole string
> +  //
> +  CopyMem (SmmGetNextVariableName->Name, VariableName,
> InVariableNameSize);
> +  if (OutVariableNameSize > InVariableNameSize) {
> +    ZeroMem ((UINT8 *)SmmGetNextVariableName->Name +
> InVariableNameSize, OutVariableNameSize - InVariableNameSize);
> +  }
> +
> +  //
> +  // Send data to SMM
> +  //
> +  Status = SendCommunicateBuffer (PayloadSize);
> +
> +  //
> +  // Get data from SMM.
> +  //
> +  if ((Status == EFI_SUCCESS) || (Status == EFI_BUFFER_TOO_SMALL)) {
> +    //
> +    // SMM CommBuffer NameSize can be a trimed value
> +    // Only update VariableNameSize when needed
> +    //
> +    *VariableNameSize = SmmGetNextVariableName->NameSize;
> +  }
> +
> +  if (EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +  CopyGuid (VendorGuid, &SmmGetNextVariableName->Guid);
> +  CopyMem (VariableName, SmmGetNextVariableName->Name,
> SmmGetNextVariableName->NameSize);
> +
> +Done:
> +  return Status;
> +}
> +
> +/**
> +  This code Finds the Next available variable.
> +
> +  @param[in, out] VariableNameSize   Size of the variable name.
> +  @param[in, out] VariableName       Pointer to variable name.
> +  @param[in, out] VendorGuid         Variable Vendor Guid.
> +
> +  @retval EFI_INVALID_PARAMETER      Invalid parameter.
> +  @retval EFI_SUCCESS                Find the specified variable.
> +  @retval EFI_NOT_FOUND              Not found.
> +  @retval EFI_BUFFER_TO_SMALL        DataSize is too small for the result.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +RuntimeServiceGetNextVariableName (
> +  IN OUT  UINTN     *VariableNameSize,
> +  IN OUT  CHAR16    *VariableName,
> +  IN OUT  EFI_GUID  *VendorGuid
> +  )
> +{
> +  EFI_STATUS  Status;
> +  UINTN       MaxLen;
> +
> +  Status = EFI_NOT_FOUND;
> +
> +  if ((VariableNameSize == NULL) || (VariableName == NULL) || (VendorGuid ==
> NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  //
> +  // Calculate the possible maximum length of name string, including the Null
> terminator.
> +  //
> +  MaxLen = *VariableNameSize / sizeof (CHAR16);
> +  if ((MaxLen == 0) || (StrnLenS (VariableName, MaxLen) == MaxLen)) {
> +    //
> +    // Null-terminator is not found in the first VariableNameSize bytes of the
> input VariableName buffer,
> +    // follow spec to return EFI_INVALID_PARAMETER.
> +    //
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mVariableServicesLock);
> +  if (FeaturePcdGet (PcdEnableVariableRuntimeCache)) {
> +    Status = GetNextVariableNameInRuntimeCache (VariableNameSize,
> VariableName, VendorGuid);
> +  } else {
> +    Status = GetNextVariableNameInSmm (VariableNameSize, VariableName,
> VendorGuid);
> +  }
> +
> +  ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
> +
> +  return Status;
> +}
> +
> +/**
> +  This code sets variable in storage blocks (Volatile or Non-Volatile).
> +
> +  Caution: This function may receive untrusted input.
> +  The data size and data are external input, so this function will validate it
> carefully to avoid buffer overflow.
> +
> +  @param[in] VariableName                 Name of Variable to be found.
> +  @param[in] VendorGuid                   Variable vendor GUID.
> +  @param[in] Attributes                   Attribute value of the variable found
> +  @param[in] DataSize                     Size of Data found. If size is less than the
> +                                          data, this value contains the required size.
> +  @param[in] Data                         Data pointer.
> +
> +  @retval EFI_INVALID_PARAMETER           Invalid parameter.
> +  @retval EFI_SUCCESS                     Set successfully.
> +  @retval EFI_OUT_OF_RESOURCES            Resource not enough to set variable.
> +  @retval EFI_NOT_FOUND                   Not found.
> +  @retval EFI_WRITE_PROTECTED             Variable is read-only.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +RuntimeServiceSetVariable (
> +  IN CHAR16    *VariableName,
> +  IN EFI_GUID  *VendorGuid,
> +  IN UINT32    Attributes,
> +  IN UINTN     DataSize,
> +  IN VOID      *Data
> +  )
> +{
> +  EFI_STATUS                                Status;
> +  UINTN                                     PayloadSize;
> +  SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE  *SmmVariableHeader;
> +  UINTN                                     VariableNameSize;
> +
> +  //
> +  // Check input parameters.
> +  //
> +  if ((VariableName == NULL) || (VariableName[0] == 0) || (VendorGuid ==
> NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if ((DataSize != 0) && (Data == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  VariableNameSize  = StrSize (VariableName);
> +  SmmVariableHeader = NULL;
> +
> +  //
> +  // If VariableName or DataSize exceeds SMM payload limit. Return failure
> +  //
> +  if ((VariableNameSize > mVariableBufferPayloadSize - OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)) ||
> +      (DataSize > mVariableBufferPayloadSize - OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) -
> VariableNameSize))
> +  {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mVariableServicesLock);
> +
> +  //
> +  // Init the communicate buffer. The buffer data size is:
> +  // SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize.
> +  //
> +  PayloadSize = OFFSET_OF
> (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) +
> VariableNameSize + DataSize;
> +  Status      = InitCommunicateBuffer ((VOID **)&SmmVariableHeader,
> PayloadSize, SMM_VARIABLE_FUNCTION_SET_VARIABLE);
> +  if (EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +  ASSERT (SmmVariableHeader != NULL);
> +
> +  CopyGuid ((EFI_GUID *)&SmmVariableHeader->Guid, VendorGuid);
> +  SmmVariableHeader->DataSize   = DataSize;
> +  SmmVariableHeader->NameSize   = VariableNameSize;
> +  SmmVariableHeader->Attributes = Attributes;
> +  CopyMem (SmmVariableHeader->Name, VariableName, SmmVariableHeader-
> >NameSize);
> +  CopyMem ((UINT8 *)SmmVariableHeader->Name + SmmVariableHeader-
> >NameSize, Data, DataSize);
> +
> +  //
> +  // Send data to SMM.
> +  //
> +  Status = SendCommunicateBuffer (PayloadSize);
> +
> +Done:
> +  ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
> +
> +  if (!EfiAtRuntime ()) {
> +    if (!EFI_ERROR (Status)) {
> +      SecureBootHook (
> +        VariableName,
> +        VendorGuid
> +        );
> +    }
> +  }
> +
> +  return Status;
> +}
> +
> +/**
> +  This code returns information about the EFI variables.
> +
> +  @param[in]  Attributes                   Attributes bitmask to specify the type of
> variables
> +                                           on which to return information.
> +  @param[out] MaximumVariableStorageSize   Pointer to the maximum size of
> the storage space available
> +                                           for the EFI variables associated with the attributes
> specified.
> +  @param[out] RemainingVariableStorageSize Pointer to the remaining size of
> the storage space available
> +                                           for EFI variables associated with the attributes specified.
> +  @param[out] MaximumVariableSize          Pointer to the maximum size of an
> individual EFI variables
> +                                           associated with the attributes specified.
> +
> +  @retval EFI_INVALID_PARAMETER            An invalid combination of attribute
> bits was supplied.
> +  @retval EFI_SUCCESS                      Query successfully.
> +  @retval EFI_UNSUPPORTED                  The attribute is not supported on this
> platform.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +RuntimeServiceQueryVariableInfo (
> +  IN  UINT32  Attributes,
> +  OUT UINT64  *MaximumVariableStorageSize,
> +  OUT UINT64  *RemainingVariableStorageSize,
> +  OUT UINT64  *MaximumVariableSize
> +  )
> +{
> +  EFI_STATUS                                    Status;
> +  UINTN                                         PayloadSize;
> +  SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO
> *SmmQueryVariableInfo;
> +
> +  SmmQueryVariableInfo = NULL;
> +
> +  if ((MaximumVariableStorageSize == NULL) || (RemainingVariableStorageSize
> == NULL) || (MaximumVariableSize == NULL) || (Attributes == 0)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mVariableServicesLock);
> +
> +  //
> +  // Init the communicate buffer. The buffer data size is:
> +  // SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize;
> +  //
> +  PayloadSize = sizeof
> (SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO);
> +  Status      = InitCommunicateBuffer ((VOID **)&SmmQueryVariableInfo,
> PayloadSize, SMM_VARIABLE_FUNCTION_QUERY_VARIABLE_INFO);
> +  if (EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +  ASSERT (SmmQueryVariableInfo != NULL);
> +
> +  SmmQueryVariableInfo->Attributes = Attributes;
> +
> +  //
> +  // Send data to SMM.
> +  //
> +  Status = SendCommunicateBuffer (PayloadSize);
> +  if (EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +  //
> +  // Get data from SMM.
> +  //
> +  *MaximumVariableSize          = SmmQueryVariableInfo->MaximumVariableSize;
> +  *MaximumVariableStorageSize   = SmmQueryVariableInfo-
> >MaximumVariableStorageSize;
> +  *RemainingVariableStorageSize = SmmQueryVariableInfo-
> >RemainingVariableStorageSize;
> +
> +Done:
> +  ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
> +  return Status;
> +}
> +
> +/**
> +  Exit Boot Services Event notification handler.
> +
> +  Notify SMM variable driver about the event.
> +
> +  @param[in]  Event     Event whose notification function is being invoked.
> +  @param[in]  Context   Pointer to the notification function's context.
> +
> +**/
> +VOID
> +EFIAPI
> +OnExitBootServices (
> +  IN      EFI_EVENT  Event,
> +  IN      VOID       *Context
> +  )
> +{
> +  //
> +  // Init the communicate buffer. The buffer data size is:
> +  // SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE.
> +  //
> +  InitCommunicateBuffer (NULL, 0,
> SMM_VARIABLE_FUNCTION_EXIT_BOOT_SERVICE);
> +
> +  //
> +  // Send data to SMM.
> +  //
> +  SendCommunicateBuffer (0);
> +}
> +
> +/**
> +  On Ready To Boot Services Event notification handler.
> +
> +  Notify SMM variable driver about the event.
> +
> +  @param[in]  Event     Event whose notification function is being invoked
> +  @param[in]  Context   Pointer to the notification function's context
> +
> +**/
> +VOID
> +EFIAPI
> +OnReadyToBoot (
> +  IN      EFI_EVENT  Event,
> +  IN      VOID       *Context
> +  )
> +{
> +  //
> +  // Init the communicate buffer. The buffer data size is:
> +  // SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE.
> +  //
> +  InitCommunicateBuffer (NULL, 0,
> SMM_VARIABLE_FUNCTION_READY_TO_BOOT);
> +
> +  //
> +  // Send data to SMM.
> +  //
> +  SendCommunicateBuffer (0);
> +
> +  //
> +  // Install the system configuration table for variable info data captured
> +  //
> +  if (FeaturePcdGet (PcdEnableVariableRuntimeCache) && FeaturePcdGet
> (PcdVariableCollectStatistics)) {
> +    if (mVariableAuthFormat) {
> +      gBS->InstallConfigurationTable (&gEfiAuthenticatedVariableGuid,
> mVariableInfo);
> +    } else {
> +      gBS->InstallConfigurationTable (&gEfiVariableGuid, mVariableInfo);
> +    }
> +  }
> +
> +  gBS->CloseEvent (Event);
> +}
> +
> +/**
> +  Notification function of EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE.
> +
> +  This is a notification function registered on
> EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE event.
> +  It convers pointer to new virtual address.
> +
> +  @param[in]  Event        Event whose notification function is being invoked.
> +  @param[in]  Context      Pointer to the notification function's context.
> +
> +**/
> +VOID
> +EFIAPI
> +VariableAddressChangeEvent (
> +  IN EFI_EVENT  Event,
> +  IN VOID       *Context
> +  )
> +{
> +  EfiConvertPointer (0x0, (VOID **)&mVariableBuffer);
> +  EfiConvertPointer (0x0, (VOID **)&mMmCommunication2);
> +  EfiConvertPointer (EFI_OPTIONAL_PTR, (VOID
> **)&mVariableRuntimeHobCacheBuffer);
> +  EfiConvertPointer (EFI_OPTIONAL_PTR, (VOID
> **)&mVariableRuntimeNvCacheBuffer);
> +  EfiConvertPointer (EFI_OPTIONAL_PTR, (VOID
> **)&mVariableRuntimeVolatileCacheBuffer);
> +}
> +
> +/**
> +  This code gets variable payload size.
> +
> +  @param[out] VariablePayloadSize   Output pointer to variable payload size.
> +
> +  @retval EFI_SUCCESS               Get successfully.
> +  @retval Others                    Get unsuccessfully.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +GetVariablePayloadSize (
> +  OUT UINTN  *VariablePayloadSize
> +  )
> +{
> +  EFI_STATUS                                 Status;
> +  SMM_VARIABLE_COMMUNICATE_GET_PAYLOAD_SIZE  *SmmGetPayloadSize;
> +  EFI_MM_COMMUNICATE_HEADER                  *SmmCommunicateHeader;
> +  SMM_VARIABLE_COMMUNICATE_HEADER
> *SmmVariableFunctionHeader;
> +  UINTN                                      CommSize;
> +  UINT8                                      *CommBuffer;
> +
> +  SmmGetPayloadSize = NULL;
> +  CommBuffer        = NULL;
> +
> +  if (VariablePayloadSize == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mVariableServicesLock);
> +
> +  //
> +  // Init the communicate buffer. The buffer data size is:
> +  // SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + sizeof
> (SMM_VARIABLE_COMMUNICATE_GET_PAYLOAD_SIZE);
> +  //
> +  CommSize   = SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + sizeof
> (SMM_VARIABLE_COMMUNICATE_GET_PAYLOAD_SIZE);
> +  CommBuffer = AllocateZeroPool (CommSize);
> +  if (CommBuffer == NULL) {
> +    Status = EFI_OUT_OF_RESOURCES;
> +    goto Done;
> +  }
> +
> +  SmmCommunicateHeader = (EFI_MM_COMMUNICATE_HEADER
> *)CommBuffer;
> +  CopyGuid (&SmmCommunicateHeader->HeaderGuid,
> &gEfiSmmVariableProtocolGuid);
> +  SmmCommunicateHeader->MessageLength =
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + sizeof
> (SMM_VARIABLE_COMMUNICATE_GET_PAYLOAD_SIZE);
> +
> +  SmmVariableFunctionHeader           =
> (SMM_VARIABLE_COMMUNICATE_HEADER *)SmmCommunicateHeader->Data;
> +  SmmVariableFunctionHeader->Function =
> SMM_VARIABLE_FUNCTION_GET_PAYLOAD_SIZE;
> +  SmmGetPayloadSize                   =
> (SMM_VARIABLE_COMMUNICATE_GET_PAYLOAD_SIZE
> *)SmmVariableFunctionHeader->Data;
> +
> +  //
> +  // Send data to SMM.
> +  //
> +  Status = mMmCommunication2->Communicate (mMmCommunication2,
> CommBuffer, CommBuffer, &CommSize);
> +  ASSERT_EFI_ERROR (Status);
> +
> +  Status = SmmVariableFunctionHeader->ReturnStatus;
> +  if (EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +  //
> +  // Get data from SMM.
> +  //
> +  *VariablePayloadSize = SmmGetPayloadSize->VariablePayloadSize;
> +
> +Done:
> +  if (CommBuffer != NULL) {
> +    FreePool (CommBuffer);
> +  }
> +
> +  ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
> +  return Status;
> +}
> +
> +/**
> +  This code gets information needed from SMM for runtime cache initialization.
> +
> +  @param[out] TotalHobStorageSize         Output pointer for the total HOB
> storage size in bytes.
> +  @param[out] TotalNvStorageSize          Output pointer for the total non-
> volatile storage size in bytes.
> +  @param[out] TotalVolatileStorageSize    Output pointer for the total volatile
> storage size in bytes.
> +  @param[out] AuthenticatedVariableUsage  Output pointer that indicates if
> authenticated variables are to be used.
> +
> +  @retval EFI_SUCCESS                     Retrieved the size successfully.
> +  @retval EFI_INVALID_PARAMETER           TotalNvStorageSize parameter is
> NULL.
> +  @retval EFI_OUT_OF_RESOURCES            The memory resources needed for a
> CommBuffer are not available.
> +  @retval Others                          Could not retrieve the size successfully.
> +
> +**/
> +EFI_STATUS
> +GetRuntimeCacheInfo (
> +  OUT UINTN    *TotalHobStorageSize,
> +  OUT UINTN    *TotalNvStorageSize,
> +  OUT UINTN    *TotalVolatileStorageSize,
> +  OUT BOOLEAN  *AuthenticatedVariableUsage
> +  )
> +{
> +  EFI_STATUS                                       Status;
> +  SMM_VARIABLE_COMMUNICATE_GET_RUNTIME_CACHE_INFO
> *SmmGetRuntimeCacheInfo;
> +  EFI_MM_COMMUNICATE_HEADER                        *SmmCommunicateHeader;
> +  SMM_VARIABLE_COMMUNICATE_HEADER
> *SmmVariableFunctionHeader;
> +  UINTN                                            CommSize;
> +  UINT8                                            *CommBuffer;
> +
> +  SmmGetRuntimeCacheInfo = NULL;
> +  CommBuffer             = mVariableBuffer;
> +
> +  if ((TotalHobStorageSize == NULL) || (TotalNvStorageSize == NULL) ||
> (TotalVolatileStorageSize == NULL) || (AuthenticatedVariableUsage == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (CommBuffer == NULL) {
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mVariableServicesLock);
> +
> +  CommSize = SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + sizeof
> (SMM_VARIABLE_COMMUNICATE_GET_RUNTIME_CACHE_INFO);
> +  ZeroMem (CommBuffer, CommSize);
> +
> +  SmmCommunicateHeader = (EFI_MM_COMMUNICATE_HEADER
> *)CommBuffer;
> +  CopyGuid (&SmmCommunicateHeader->HeaderGuid,
> &gEfiSmmVariableProtocolGuid);
> +  SmmCommunicateHeader->MessageLength =
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + sizeof
> (SMM_VARIABLE_COMMUNICATE_GET_RUNTIME_CACHE_INFO);
> +
> +  SmmVariableFunctionHeader           =
> (SMM_VARIABLE_COMMUNICATE_HEADER *)SmmCommunicateHeader->Data;
> +  SmmVariableFunctionHeader->Function =
> SMM_VARIABLE_FUNCTION_GET_RUNTIME_CACHE_INFO;
> +  SmmGetRuntimeCacheInfo              =
> (SMM_VARIABLE_COMMUNICATE_GET_RUNTIME_CACHE_INFO
> *)SmmVariableFunctionHeader->Data;
> +
> +  //
> +  // Send data to SMM.
> +  //
> +  Status = mMmCommunication2->Communicate (mMmCommunication2,
> CommBuffer, CommBuffer, &CommSize);
> +  ASSERT_EFI_ERROR (Status);
> +  if (CommSize <= SMM_VARIABLE_COMMUNICATE_HEADER_SIZE) {
> +    Status = EFI_BAD_BUFFER_SIZE;
> +    goto Done;
> +  }
> +
> +  Status = SmmVariableFunctionHeader->ReturnStatus;
> +  if (EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +  //
> +  // Get data from SMM.
> +  //
> +  *TotalHobStorageSize        = SmmGetRuntimeCacheInfo-
> >TotalHobStorageSize;
> +  *TotalNvStorageSize         = SmmGetRuntimeCacheInfo->TotalNvStorageSize;
> +  *TotalVolatileStorageSize   = SmmGetRuntimeCacheInfo-
> >TotalVolatileStorageSize;
> +  *AuthenticatedVariableUsage = SmmGetRuntimeCacheInfo-
> >AuthenticatedVariableUsage;
> +
> +Done:
> +  ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
> +  return Status;
> +}
> +
> +/**
> +  Sends the runtime variable cache context information to SMM.
> +
> +  @retval EFI_SUCCESS               Retrieved the size successfully.
> +  @retval EFI_INVALID_PARAMETER     TotalNvStorageSize parameter is NULL.
> +  @retval EFI_OUT_OF_RESOURCES      The memory resources needed for a
> CommBuffer are not available.
> +  @retval Others                    Could not retrieve the size successfully.;
> +
> +**/
> +EFI_STATUS
> +SendRuntimeVariableCacheContextToSmm (
> +  VOID
> +  )
> +{
> +  EFI_STATUS                                               Status;
> +  SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT
> *SmmRuntimeVarCacheContext;
> +  EFI_MM_COMMUNICATE_HEADER
> *SmmCommunicateHeader;
> +  SMM_VARIABLE_COMMUNICATE_HEADER
> *SmmVariableFunctionHeader;
> +  UINTN                                                    CommSize;
> +  UINT8                                                    *CommBuffer;
> +
> +  SmmRuntimeVarCacheContext = NULL;
> +  CommBuffer                = mVariableBuffer;
> +
> +  if (CommBuffer == NULL) {
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +
> +  AcquireLockOnlyAtBootTime (&mVariableServicesLock);
> +
> +  //
> +  // Init the communicate buffer. The buffer data size is:
> +  // SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + sizeof
> (SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT);
> +  //
> +  CommSize = SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + sizeof
> (SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT);
> +  ZeroMem (CommBuffer, CommSize);
> +
> +  SmmCommunicateHeader = (EFI_MM_COMMUNICATE_HEADER
> *)CommBuffer;
> +  CopyGuid (&SmmCommunicateHeader->HeaderGuid,
> &gEfiSmmVariableProtocolGuid);
> +  SmmCommunicateHeader->MessageLength =
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + sizeof
> (SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT);
> +
> +  SmmVariableFunctionHeader           =
> (SMM_VARIABLE_COMMUNICATE_HEADER *)SmmCommunicateHeader->Data;
> +  SmmVariableFunctionHeader->Function =
> SMM_VARIABLE_FUNCTION_INIT_RUNTIME_VARIABLE_CACHE_CONTEXT;
> +  SmmRuntimeVarCacheContext           =
> (SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT
> *)SmmVariableFunctionHeader->Data;
> +
> +  SmmRuntimeVarCacheContext->RuntimeHobCache      =
> mVariableRuntimeHobCacheBuffer;
> +  SmmRuntimeVarCacheContext->RuntimeVolatileCache =
> mVariableRuntimeVolatileCacheBuffer;
> +  SmmRuntimeVarCacheContext->RuntimeNvCache       =
> mVariableRuntimeNvCacheBuffer;
> +  SmmRuntimeVarCacheContext->PendingUpdate        =
> &mVariableRuntimeCachePendingUpdate;
> +  SmmRuntimeVarCacheContext->ReadLock             =
> &mVariableRuntimeCacheReadLock;
> +  SmmRuntimeVarCacheContext->HobFlushComplete     =
> &mHobFlushComplete;
> +
> +  //
> +  // Request to unblock this region to be accessible from inside MM
> environment
> +  // These fields "should" be all on the same page, but just to be on the safe
> side...
> +  //
> +  Status = MmUnblockMemoryRequest (
> +             (EFI_PHYSICAL_ADDRESS)ALIGN_VALUE
> ((UINTN)SmmRuntimeVarCacheContext->PendingUpdate - EFI_PAGE_SIZE + 1,
> EFI_PAGE_SIZE),
> +             EFI_SIZE_TO_PAGES (sizeof (mVariableRuntimeCachePendingUpdate))
> +             );
> +  if ((Status != EFI_UNSUPPORTED) && EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +  Status = MmUnblockMemoryRequest (
> +             (EFI_PHYSICAL_ADDRESS)ALIGN_VALUE
> ((UINTN)SmmRuntimeVarCacheContext->ReadLock - EFI_PAGE_SIZE + 1,
> EFI_PAGE_SIZE),
> +             EFI_SIZE_TO_PAGES (sizeof (mVariableRuntimeCacheReadLock))
> +             );
> +  if ((Status != EFI_UNSUPPORTED) && EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +  Status = MmUnblockMemoryRequest (
> +             (EFI_PHYSICAL_ADDRESS)ALIGN_VALUE
> ((UINTN)SmmRuntimeVarCacheContext->HobFlushComplete - EFI_PAGE_SIZE +
> 1, EFI_PAGE_SIZE),
> +             EFI_SIZE_TO_PAGES (sizeof (mHobFlushComplete))
> +             );
> +  if ((Status != EFI_UNSUPPORTED) && EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +  //
> +  // Send data to SMM.
> +  //
> +  Status = mMmCommunication2->Communicate (mMmCommunication2,
> CommBuffer, CommBuffer, &CommSize);
> +  ASSERT_EFI_ERROR (Status);
> +  if (CommSize <= SMM_VARIABLE_COMMUNICATE_HEADER_SIZE) {
> +    Status = EFI_BAD_BUFFER_SIZE;
> +    goto Done;
> +  }
> +
> +  Status = SmmVariableFunctionHeader->ReturnStatus;
> +  if (EFI_ERROR (Status)) {
> +    goto Done;
> +  }
> +
> +Done:
> +  ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
> +  return Status;
> +}
> +
> +/**
> +  Initialize variable service and install Variable Architectural protocol.
> +
> +  @param[in] Event    Event whose notification function is being invoked.
> +  @param[in] Context  Pointer to the notification function's context.
> +
> +**/
> +VOID
> +EFIAPI
> +SmmVariableReady (
> +  IN  EFI_EVENT  Event,
> +  IN  VOID       *Context
> +  )
> +{
> +  EFI_STATUS                     Status;
> +  PROTECTED_VARIABLE_CONTEXT_IN  ContextIn;
> +
> +  Status = gBS->LocateProtocol (&gEfiSmmVariableProtocolGuid, NULL, (VOID
> **)&mSmmVariable);
> +  if (EFI_ERROR (Status)) {
> +    return;
> +  }
> +
> +  Status = gBS->LocateProtocol (&gEfiMmCommunication2ProtocolGuid, NULL,
> (VOID **)&mMmCommunication2);
> +  ASSERT_EFI_ERROR (Status);
> +
> +  //
> +  // Allocate memory for variable communicate buffer.
> +  //
> +  Status = GetVariablePayloadSize (&mVariableBufferPayloadSize);
> +  ASSERT_EFI_ERROR (Status);
> +  mVariableBufferSize = SMM_COMMUNICATE_HEADER_SIZE +
> SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + mVariableBufferPayloadSize;
> +  mVariableBuffer     = AllocateRuntimePool (mVariableBufferSize);
> +  ASSERT (mVariableBuffer != NULL);
> +
> +  //
> +  // Save the buffer physical address used for SMM conmunication.
> +  //
> +  mVariableBufferPhysical = mVariableBuffer;
> +
> +  if (FeaturePcdGet (PcdEnableVariableRuntimeCache)) {
> +    DEBUG ((DEBUG_INFO, "Variable driver runtime cache is enabled.\n"));
> +    //
> +    // Allocate runtime variable cache memory buffers.
> +    //
> +    Status =  GetRuntimeCacheInfo (
> +                &mVariableRuntimeHobCacheBufferSize,
> +                &mVariableRuntimeNvCacheBufferSize,
> +                &mVariableRuntimeVolatileCacheBufferSize,
> +                &mVariableAuthFormat
> +                );
> +    if (!EFI_ERROR (Status)) {
> +      Status = InitVariableCache (&mVariableRuntimeHobCacheBuffer,
> &mVariableRuntimeHobCacheBufferSize);
> +      if (!EFI_ERROR (Status)) {
> +        Status = InitVariableCache (&mVariableRuntimeNvCacheBuffer,
> &mVariableRuntimeNvCacheBufferSize);
> +        if (!EFI_ERROR (Status)) {
> +          Status = InitVariableCache (&mVariableRuntimeVolatileCacheBuffer,
> &mVariableRuntimeVolatileCacheBufferSize);
> +          if (!EFI_ERROR (Status)) {
> +            Status = SendRuntimeVariableCacheContextToSmm ();
> +            if (!EFI_ERROR (Status)) {
> +              SyncRuntimeCache ();
> +            }
> +          }
> +        }
> +      }
> +
> +      if (EFI_ERROR (Status)) {
> +        mVariableRuntimeHobCacheBuffer      = NULL;
> +        mVariableRuntimeNvCacheBuffer       = NULL;
> +        mVariableRuntimeVolatileCacheBuffer = NULL;
> +      }
> +    }
> +
> +    ASSERT_EFI_ERROR (Status);
> +  } else {
> +    DEBUG ((DEBUG_INFO, "Variable driver runtime cache is disabled.\n"));
> +  }
> +
> +  gRT->GetVariable         = RuntimeServiceGetVariable;
> +  gRT->GetNextVariableName = RuntimeServiceGetNextVariableName;
> +  gRT->SetVariable         = RuntimeServiceSetVariable;
> +  gRT->QueryVariableInfo   = RuntimeServiceQueryVariableInfo;
> +
> +  //
> +  // Install the Variable Architectural Protocol on a new handle.
> +  //
> +  Status = gBS->InstallProtocolInterface (
> +                  &mHandle,
> +                  &gEfiVariableArchProtocolGuid,
> +                  EFI_NATIVE_INTERFACE,
> +                  NULL
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  mVariableLock.RequestToLock = VariableLockRequestToLock;
> +  Status                      = gBS->InstallMultipleProtocolInterfaces (
> +                                       &mHandle,
> +                                       &gEdkiiVariableLockProtocolGuid,
> +                                       &mVariableLock,
> +                                       NULL
> +                                       );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  mVarCheck.RegisterSetVariableCheckHandler =
> VarCheckRegisterSetVariableCheckHandler;
> +  mVarCheck.VariablePropertySet             = VarCheckVariablePropertySet;
> +  mVarCheck.VariablePropertyGet             = VarCheckVariablePropertyGet;
> +  Status                                    = gBS->InstallMultipleProtocolInterfaces (
> +                                                     &mHandle,
> +                                                     &gEdkiiVarCheckProtocolGuid,
> +                                                     &mVarCheck,
> +                                                     NULL
> +                                                     );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  ContextIn.StructSize    = sizeof (ContextIn);
> +  ContextIn.StructVersion =
> PROTECTED_VARIABLE_CONTEXT_IN_STRUCT_VERSION;
> +
> +  ContextIn.FindVariableSmm     = FindVariableInSmm;
> +  ContextIn.GetVariableInfo     = GetVariableInfo;
> +  ContextIn.GetNextVariableInfo = GetNextVariableInfo;
> +  ContextIn.VariableServiceUser = FromRuntimeModule;
> +  ContextIn.MaxVariableSize     = 0;
> +  ContextIn.UpdateVariableStore = NULL;
> +  ContextIn.UpdateVariable      = NULL;
> +
> +  Status = ProtectedVariableLibInitialize (&ContextIn);
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((
> +      DEBUG_INFO,
> +      "%a: %d ProtectedVariableLibInitialize() return status: %r\n",
> +      __FUNCTION__,
> +      __LINE__,
> +      Status
> +      ));
> +  }
> +
> +  gBS->CloseEvent (Event);
> +}
> +
> +/**
> +  SMM Non-Volatile variable write service is ready notify event handler.
> +
> +  @param[in] Event    Event whose notification function is being invoked.
> +  @param[in] Context  Pointer to the notification function's context.
> +
> +**/
> +VOID
> +EFIAPI
> +SmmVariableWriteReady (
> +  IN  EFI_EVENT  Event,
> +  IN  VOID       *Context
> +  )
> +{
> +  EFI_STATUS  Status;
> +  VOID        *ProtocolOps;
> +
> +  //
> +  // Check whether the protocol is installed or not.
> +  //
> +  Status = gBS->LocateProtocol (&gSmmVariableWriteGuid, NULL, (VOID
> **)&ProtocolOps);
> +  if (EFI_ERROR (Status)) {
> +    return;
> +  }
> +
> +  //
> +  // Some Secure Boot Policy Var (SecureBoot, etc) updates following other
> +  // Secure Boot Policy Variable change.  Record their initial value.
> +  //
> +  RecordSecureBootPolicyVarData ();
> +
> +  Status = gBS->InstallProtocolInterface (
> +                  &mHandle,
> +                  &gEfiVariableWriteArchProtocolGuid,
> +                  EFI_NATIVE_INTERFACE,
> +                  NULL
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  gBS->CloseEvent (Event);
> +}
> +
> +/**
> +  Variable Driver main entry point. The Variable driver places the 4 EFI
> +  runtime services in the EFI System Table and installs arch protocols
> +  for variable read and write services being available. It also registers
> +  a notification function for an EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE
> event.
> +
> +  @param[in] ImageHandle    The firmware allocated handle for the EFI image.
> +  @param[in] SystemTable    A pointer to the EFI System Table.
> +
> +  @retval EFI_SUCCESS       Variable service successfully initialized.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableSmmRuntimeInitialize (
> +  IN EFI_HANDLE        ImageHandle,
> +  IN EFI_SYSTEM_TABLE  *SystemTable
> +  )
> +{
> +  VOID       *SmmVariableRegistration;
> +  VOID       *SmmVariableWriteRegistration;
> +  EFI_EVENT  OnReadyToBootEvent;
> +  EFI_EVENT  ExitBootServiceEvent;
> +  EFI_EVENT  LegacyBootEvent;
> +
> +  EfiInitializeLock (&mVariableServicesLock, TPL_NOTIFY);
> +
> +  //
> +  // Smm variable service is ready
> +  //
> +  EfiCreateProtocolNotifyEvent (
> +    &gEfiSmmVariableProtocolGuid,
> +    TPL_CALLBACK,
> +    SmmVariableReady,
> +    NULL,
> +    &SmmVariableRegistration
> +    );
> +
> +  //
> +  // Smm Non-Volatile variable write service is ready
> +  //
> +  EfiCreateProtocolNotifyEvent (
> +    &gSmmVariableWriteGuid,
> +    TPL_CALLBACK,
> +    SmmVariableWriteReady,
> +    NULL,
> +    &SmmVariableWriteRegistration
> +    );
> +
> +  //
> +  // Register the event to reclaim variable for OS usage.
> +  //
> +  EfiCreateEventReadyToBootEx (
> +    TPL_NOTIFY,
> +    OnReadyToBoot,
> +    NULL,
> +    &OnReadyToBootEvent
> +    );
> +
> +  //
> +  // Register the event to inform SMM variable that it is at runtime.
> +  //
> +  gBS->CreateEventEx (
> +         EVT_NOTIFY_SIGNAL,
> +         TPL_NOTIFY,
> +         OnExitBootServices,
> +         NULL,
> +         &gEfiEventExitBootServicesGuid,
> +         &ExitBootServiceEvent
> +         );
> +
> +  //
> +  // Register the event to inform SMM variable that it is at runtime for legacy
> boot.
> +  // Reuse OnExitBootServices() here.
> +  //
> +  EfiCreateEventLegacyBootEx (
> +    TPL_NOTIFY,
> +    OnExitBootServices,
> +    NULL,
> +    &LegacyBootEvent
> +    );
> +
> +  //
> +  // Register the event to convert the pointer for runtime.
> +  //
> +  gBS->CreateEventEx (
> +         EVT_NOTIFY_SIGNAL,
> +         TPL_NOTIFY,
> +         VariableAddressChangeEvent,
> +         NULL,
> +         &gEfiEventVirtualAddressChangeGuid,
> +         &mVirtualAddressChangeEvent
> +         );
> +
> +  // Initialize the VariablePolicy protocol and engine.
> +  VariablePolicySmmDxeMain (ImageHandle, SystemTable);
> +
> +  return EFI_SUCCESS;
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableStandalon
> eMm.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableStandalon
> eMm.c
> new file mode 100644
> index 000000000000..943993eb6738
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableStandalon
> eMm.c
> @@ -0,0 +1,89 @@
> +/** @file
> +
> +  Parts of the SMM/MM implementation that are specific to standalone MM
> +
> +Copyright (c) 2011 - 2018, Intel Corporation. All rights reserved. <BR>
> +Copyright (c) 2018, Linaro, Ltd. All rights reserved. <BR>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include "Variable.h"
> +
> +/**
> +  This function checks if the buffer is valid per processor architecture and
> +  does not overlap with SMRAM.
> +
> +  @param Buffer The buffer start address to be checked.
> +  @param Length The buffer length to be checked.
> +
> +  @retval TRUE  This buffer is valid per processor architecture and does not
> +                overlap with SMRAM.
> +  @retval FALSE This buffer is not valid per processor architecture or overlaps
> +                with SMRAM.
> +**/
> +BOOLEAN
> +VariableSmmIsBufferOutsideSmmValid (
> +  IN EFI_PHYSICAL_ADDRESS  Buffer,
> +  IN UINT64                Length
> +  )
> +{
> +  return TRUE;
> +}
> +
> +/**
> +  Notify the system that the SMM variable driver is ready.
> +**/
> +VOID
> +VariableNotifySmmReady (
> +  VOID
> +  )
> +{
> +}
> +
> +/**
> +  Notify the system that the SMM variable write driver is ready.
> +**/
> +VOID
> +VariableNotifySmmWriteReady (
> +  VOID
> +  )
> +{
> +}
> +
> +/**
> +  Variable service MM driver entry point.
> +
> +  @param[in] ImageHandle    A handle for the image that is initializing this
> +                            driver
> +  @param[in] MmSystemTable  A pointer to the MM system table
> +
> +  @retval EFI_SUCCESS       Variable service successfully initialized.
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableServiceInitialize (
> +  IN EFI_HANDLE           ImageHandle,
> +  IN EFI_MM_SYSTEM_TABLE  *MmSystemTable
> +  )
> +{
> +  return MmVariableServiceInitialize ();
> +}
> +
> +/**
> +  Whether the TCG or TCG2 protocols are installed in the UEFI protocol
> database.
> +  This information is used by the MorLock code to infer whether an existing
> +  MOR variable is legitimate or not.
> +
> +  @retval TRUE  Either the TCG or TCG2 protocol is installed in the UEFI
> +                protocol database
> +  @retval FALSE Neither the TCG nor the TCG2 protocol is installed in the UEFI
> +                protocol database
> +**/
> +BOOLEAN
> +VariableHaveTcgProtocols (
> +  VOID
> +  )
> +{
> +  return FALSE;
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableTradition
> alMm.c
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableTradition
> alMm.c
> new file mode 100644
> index 000000000000..0369c3cd01b1
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableTradition
> alMm.c
> @@ -0,0 +1,130 @@
> +/** @file
> +
> +  Parts of the SMM/MM implementation that are specific to traditional MM
> +
> +Copyright (c) 2011 - 2018, Intel Corporation. All rights reserved. <BR>
> +Copyright (c) 2018, Linaro, Ltd. All rights reserved. <BR>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <Library/UefiBootServicesTableLib.h>
> +#include <Library/SmmMemLib.h>
> +#include "Variable.h"
> +
> +/**
> +  This function checks if the buffer is valid per processor architecture and
> +  does not overlap with SMRAM.
> +
> +  @param Buffer The buffer start address to be checked.
> +  @param Length The buffer length to be checked.
> +
> +  @retval TRUE  This buffer is valid per processor architecture and does not
> +                overlap with SMRAM.
> +  @retval FALSE This buffer is not valid per processor architecture or overlaps
> +                with SMRAM.
> +**/
> +BOOLEAN
> +VariableSmmIsBufferOutsideSmmValid (
> +  IN EFI_PHYSICAL_ADDRESS  Buffer,
> +  IN UINT64                Length
> +  )
> +{
> +  return SmmIsBufferOutsideSmmValid (Buffer, Length);
> +}
> +
> +/**
> +  Notify the system that the SMM variable driver is ready.
> +**/
> +VOID
> +VariableNotifySmmReady (
> +  VOID
> +  )
> +{
> +  EFI_STATUS  Status;
> +  EFI_HANDLE  Handle;
> +
> +  Handle = NULL;
> +  Status = gBS->InstallProtocolInterface (
> +                  &Handle,
> +                  &gEfiSmmVariableProtocolGuid,
> +                  EFI_NATIVE_INTERFACE,
> +                  NULL
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +}
> +
> +/**
> +  Notify the system that the SMM variable write driver is ready.
> +**/
> +VOID
> +VariableNotifySmmWriteReady (
> +  VOID
> +  )
> +{
> +  EFI_STATUS  Status;
> +  EFI_HANDLE  Handle;
> +
> +  Handle = NULL;
> +  Status = gBS->InstallProtocolInterface (
> +                  &Handle,
> +                  &gSmmVariableWriteGuid,
> +                  EFI_NATIVE_INTERFACE,
> +                  NULL
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +}
> +
> +/**
> +  Variable service MM driver entry point
> +
> +  @param[in] ImageHandle    A handle for the image that is initializing this
> +                            driver
> +  @param[in] SystemTable    A pointer to the EFI system table
> +
> +  @retval EFI_SUCCESS       Variable service successfully initialized.
> +**/
> +EFI_STATUS
> +EFIAPI
> +VariableServiceInitialize (
> +  IN EFI_HANDLE        ImageHandle,
> +  IN EFI_SYSTEM_TABLE  *SystemTable
> +  )
> +{
> +  return MmVariableServiceInitialize ();
> +}
> +
> +/**
> +  Whether the TCG or TCG2 protocols are installed in the UEFI protocol
> database.
> +  This information is used by the MorLock code to infer whether an existing
> +  MOR variable is legitimate or not.
> +
> +  @retval TRUE  Either the TCG or TCG2 protocol is installed in the UEFI
> +                protocol database
> +  @retval FALSE Neither the TCG nor the TCG2 protocol is installed in the UEFI
> +                protocol database
> +**/
> +BOOLEAN
> +VariableHaveTcgProtocols (
> +  VOID
> +  )
> +{
> +  EFI_STATUS  Status;
> +  VOID        *Interface;
> +
> +  Status = gBS->LocateProtocol (
> +                  &gEfiTcg2ProtocolGuid,
> +                  NULL,                     // Registration
> +                  &Interface
> +                  );
> +  if (!EFI_ERROR (Status)) {
> +    return TRUE;
> +  }
> +
> +  Status = gBS->LocateProtocol (
> +                  &gEfiTcgProtocolGuid,
> +                  NULL,                     // Registration
> +                  &Interface
> +                  );
> +  return !EFI_ERROR (Status);
> +}
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeD
> xe.uni
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeD
> xe.uni
> new file mode 100644
> index 000000000000..227b8c6fad24
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeD
> xe.uni
> @@ -0,0 +1,22 @@
> +// /** @file
> +// Provides variable service.
> +//
> +// This module installs variable arch protocol and variable write arch protocol
> to provide
> +// variable services: SetVariable, GetVariable, GetNextVariableName and
> QueryVariableInfo.
> +//
> +// Caution: This module requires additional review when modified.
> +// This driver will have external input - variable data.
> +// This external input must be validated carefully to avoid security issues such
> as
> +// buffer overflow or integer overflow.
> +//
> +// Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>
> +//
> +// SPDX-License-Identifier: BSD-2-Clause-Patent
> +//
> +// **/
> +
> +
> +#string STR_MODULE_ABSTRACT             #language en-US "Provides variable
> service"
> +
> +#string STR_MODULE_DESCRIPTION          #language en-US "This module
> installs variable arch protocol and variable write arch protocol to provide
> variable services: SetVariable, GetVariable, GetNextVariableName and
> QueryVariableInfo. Caution: This module requires additional review when
> modified. This driver will have external input - variable data. This external input
> must be validated carefully to avoid security issues such as buffer overflow or
> integer overflow."
> +
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeD
> xeExtra.uni
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeD
> xeExtra.uni
> new file mode 100644
> index 000000000000..f0976418ff81
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableRuntimeD
> xeExtra.uni
> @@ -0,0 +1,14 @@
> +// /** @file
> +// VariableRuntimeDxe Localized Strings and Content
> +//
> +// Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
> +//
> +// SPDX-License-Identifier: BSD-2-Clause-Patent
> +//
> +// **/
> +
> +#string STR_PROPERTIES_MODULE_NAME
> +#language en-US
> +"VariableRuntimeDxe module"
> +
> +
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmm.uni
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmm.uni
> new file mode 100644
> index 000000000000..414c7cdc7c05
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmm.uni
> @@ -0,0 +1,27 @@
> +// /** @file
> +// Provides SMM variable service.
> +//
> +// This module installs SMM variable protocol into SMM protocol database,
> +// which can be used by SMM driver, and installs SMM variable protocol
> +// into BS protocol database, which can be used to notify the SMM Runtime
> +// Dxe driver that the SMM variable service is ready.
> +// This module should be used with SMM Runtime DXE module together. The
> +// SMM Runtime DXE module would install variable arch protocol and variable
> +// write arch protocol based on SMM variable module.
> +//
> +// Caution: This module requires additional review when modified.
> +// This driver will have external input - variable data and communicate buffer in
> SMM mode.
> +// This external input must be validated carefully to avoid security issues such
> as
> +// buffer overflow or integer overflow.
> +//
> +// Copyright (c) 2010 - 2015, Intel Corporation. All rights reserved.<BR>
> +//
> +// SPDX-License-Identifier: BSD-2-Clause-Patent
> +//
> +// **/
> +
> +
> +#string STR_MODULE_ABSTRACT             #language en-US "Provides SMM
> variable service"
> +
> +#string STR_MODULE_DESCRIPTION          #language en-US "This module
> installs SMM variable protocol into SMM protocol database, which can be used
> by SMM driver, and installs SMM variable protocol into BS protocol database,
> which can be used to notify the SMM Runtime DXE driver that the SMM variable
> service is ready. This module should be used with SMM Runtime DXE module
> together. The SMM Runtime DXE module would install variable arch protocol
> and variable write arch protocol based on SMM variable module. Caution: This
> module requires additional review when modified. This driver will have external
> input - variable data and communicate buffer in SMM mode. This external input
> must be validated carefully to avoid security issues such as buffer overflow or
> integer overflow."
> +
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmExtr
> a.uni
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmExtr
> a.uni
> new file mode 100644
> index 000000000000..f724209f3dc2
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmExtr
> a.uni
> @@ -0,0 +1,14 @@
> +// /** @file
> +// VariableSmm Localized Strings and Content
> +//
> +// Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
> +//
> +// SPDX-License-Identifier: BSD-2-Clause-Patent
> +//
> +// **/
> +
> +#string STR_PROPERTIES_MODULE_NAME
> +#language en-US
> +"VariableSmm module"
> +
> +
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmRunt
> imeDxe.uni
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmRunt
> imeDxe.uni
> new file mode 100644
> index 000000000000..9639f00077a0
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmRunt
> imeDxe.uni
> @@ -0,0 +1,23 @@
> +// /** @file
> +// This module is the Runtime DXE part correspond to SMM variable module.
> +//
> +// It installs variable arch protocol and variable write arch protocol to provide
> +// four EFI_RUNTIME_SERVICES: SetVariable, GetVariable,
> GetNextVariableName and QueryVariableInfo
> +// and works with SMM variable module together.
> +//
> +// Caution: This module requires additional review when modified.
> +// This driver will have external input - variable data.
> +// This external input must be validated carefully to avoid security issues such
> as
> +// buffer overflow or integer overflow.
> +//
> +// Copyright (c) 2010 - 2014, Intel Corporation. All rights reserved.<BR>
> +//
> +// SPDX-License-Identifier: BSD-2-Clause-Patent
> +//
> +// **/
> +
> +
> +#string STR_MODULE_ABSTRACT             #language en-US "The Runtime DXE
> part corresponding to the SMM variable module"
> +
> +#string STR_MODULE_DESCRIPTION          #language en-US "It installs variable
> arch protocol and variable write arch protocol to provide four
> EFI_RUNTIME_SERVICES: SetVariable, GetVariable, GetNextVariableName and
> QueryVariableInfo and works with SMM variable module together."
> +
> diff --git
> a/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmRunt
> imeDxeExtra.uni
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmRunt
> imeDxeExtra.uni
> new file mode 100644
> index 000000000000..bbabdf82736b
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/Protected/RuntimeDxe/VariableSmmRunt
> imeDxeExtra.uni
> @@ -0,0 +1,14 @@
> +// /** @file
> +// VariableSmmRuntimeDxe Localized Strings and Content
> +//
> +// Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
> +//
> +// SPDX-License-Identifier: BSD-2-Clause-Patent
> +//
> +// **/
> +
> +#string STR_PROPERTIES_MODULE_NAME
> +#language en-US
> +"VariableSmmRuntimeDxe module"
> +
> +
> --
> 2.35.1.windows.2


  reply	other threads:[~2022-11-14  7:14 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-06  7:34 [PATCH v5 00/19] UEFI variable protection Judah Vang
2022-11-06  7:34 ` [PATCH v5 01/19] MdePkg: Add reference to new Ppi Guid Judah Vang
2022-11-06  7:34 ` [PATCH v5 02/19] MdeModulePkg: Update AUTH_VARIABLE_INFO struct Judah Vang
2022-11-06  7:34 ` [PATCH v5 03/19] MdeModulePkg: Add new ProtectedVariable GUIDs Judah Vang
2022-11-06  7:34 ` [PATCH v5 04/19] MdeModulePkg: Add new include files Judah Vang
2022-11-22  6:31   ` Wang, Jian J
2022-11-06  7:34 ` [PATCH v5 05/19] MdeModulePkg: Add new GUID for Variable Store Info Judah Vang
2022-11-06  7:34 ` [PATCH v5 06/19] MdeModulePkg: Add Null ProtectedVariable Library Judah Vang
2022-11-22  6:39   ` Wang, Jian J
2022-11-06  7:34 ` [PATCH v5 07/19] MdeModulePkg: Add new Variable functionality Judah Vang
2022-11-14  3:43   ` Wang, Jian J
     [not found]   ` <1727569A8ECB6F9D.19699@groups.io>
2022-11-14  4:27     ` [edk2-devel] " Wang, Jian J
2022-11-06  7:34 ` [PATCH v5 08/19] MdeModulePkg: Add support for Protected Variables Judah Vang
2022-11-14  7:14   ` Wang, Jian J [this message]
2022-11-14 17:19     ` Judah Vang
2022-11-15  8:49       ` [edk2-devel] " Sami Mujawar
2022-11-22  6:26         ` Wang, Jian J
     [not found]         ` <1729D430BF77E016.5511@groups.io>
2022-11-22  6:42           ` Wang, Jian J
2022-11-06  7:34 ` [PATCH v5 09/19] MdeModulePkg: Reference Null ProtectedVariableLib Judah Vang
2022-11-22  6:44   ` Wang, Jian J
2022-11-06  7:35 ` [PATCH v5 10/19] SecurityPkg: Add new GUIDs for Judah Vang
2022-11-06  7:35 ` [PATCH v5 11/19] SecurityPkg: Add new KeyService types and defines Judah Vang
2022-11-22  6:46   ` Wang, Jian J
2022-11-06  7:35 ` [PATCH v5 12/19] SecurityPkg: Add new variable types and functions Judah Vang
2022-11-06  7:35 ` [PATCH v5 13/19] SecurityPkg: Update RPMC APIs with index Judah Vang
2022-11-06  7:35 ` [PATCH v5 14/19] SecurityPkg: Fix GetVariableKey API Judah Vang
2022-11-06  7:35 ` [PATCH v5 15/19] SecurityPkg: Add null encryption variable libs Judah Vang
2022-11-22  6:55   ` Wang, Jian J
2022-11-06  7:35 ` [PATCH v5 16/19] SecurityPkg: Add VariableKey library function Judah Vang
2022-11-06  7:35 ` [PATCH v5 17/19] SecurityPkg: Add EncryptionVariable lib with AES Judah Vang
2022-11-22  7:15   ` Wang, Jian J
2022-11-06  7:35 ` [PATCH v5 18/19] SecurityPkg: Add Protected Variable Services Judah Vang
2022-11-22  7:59   ` Wang, Jian J
2022-11-06  7:35 ` [PATCH v5 19/19] SecurityPkg: Add references to new *.inf files Judah Vang
2022-11-22  8:05   ` Wang, Jian J
2022-12-09  8:03 ` [edk2-devel] [PATCH v5 00/19] UEFI variable protection Yao, Jiewen
     [not found] ` <172F11512E3044E7.1612@groups.io>
2022-12-09  9:41   ` Yao, Jiewen

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