[PATCH] MdeModulePkg/VariableSmmRuntimeDxe: Refactor locating Variable Arch Protocol

[Jagadeesh Ujja <jagadeesh.ujja@arm.com>]

In preparation for providing a standalone MM based non-secure variable
runtime driver, factor out some portions that are specific to the
traditional driver, mainly related to locating variable arch protocol
and variable write arch protocol, which are not required to be located
when using standalone MM based secure variable implementation.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jagadeesh Ujja <jagadeesh.ujja@arm.com>
---
 MdeModulePkg/Universal/Variable/RuntimeDxe/PrivilegePolymorphic.h             | 18 ++++
 MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c            |  9 +-
 MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.inf          |  1 +
 MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMmRuntimeDxe.c   | 42 +++++++++
 MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMmRuntimeDxe.inf | 95 ++++++++++++++++++++
 MdeModulePkg/Universal/Variable/RuntimeDxe/VariableTraditionalMmRuntimeDxe.c  | 45 ++++++++++
 6 files changed, 203 insertions(+), 7 deletions(-)

diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/PrivilegePolymorphic.h b/MdeModulePkg/Universal/Variable/RuntimeDxe/PrivilegePolymorphic.h
index 9b294e6..c566660 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/PrivilegePolymorphic.h
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/PrivilegePolymorphic.h
@@ -160,4 +160,22 @@ VariableHaveTcgProtocols (
   VOID
   );
 
+/**
+  Check whether the protocol is installed or not.
+**/
+EFI_STATUS
+EFIAPI
+VariableLocateSmmReady (
+  VOID
+  );
+
+/**
+  Check whether the protocol is installed or not.
+**/
+EFI_STATUS
+EFIAPI
+VariableLocateSmmWriteReady (
+  VOID
+  );
+
 #endif
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c
index 85d655d..2976f04 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c
@@ -47,7 +47,6 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #include "PrivilegePolymorphic.h"
 
 EFI_HANDLE                       mHandle                    = NULL;
-EFI_SMM_VARIABLE_PROTOCOL       *mSmmVariable               = NULL;
 EFI_EVENT                        mVirtualAddressChangeEvent = NULL;
 EFI_SMM_COMMUNICATION_PROTOCOL  *mSmmCommunication          = NULL;
 UINT8                           *mVariableBuffer            = NULL;
@@ -991,7 +990,7 @@ SmmVariableReady (
 {
   EFI_STATUS                                Status;
 
-  Status = gBS->LocateProtocol (&gEfiSmmVariableProtocolGuid, NULL, (VOID **)&mSmmVariable);
+  Status = VariableLocateSmmReady ();
   if (EFI_ERROR (Status)) {
     return;
   }
@@ -1068,12 +1067,8 @@ SmmVariableWriteReady (
   )
 {
   EFI_STATUS                                Status;
-  VOID                                      *ProtocolOps;
 
-  //
-  // Check whether the protocol is installed or not.
-  //
-  Status = gBS->LocateProtocol (&gSmmVariableWriteGuid, NULL, (VOID **) &ProtocolOps);
+  Status = VariableLocateSmmWriteReady ();
   if (EFI_ERROR (Status)) {
     return;
   }
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.inf b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.inf
index bd73f7a..103acfa 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.inf
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.inf
@@ -41,6 +41,7 @@
 #
 
 [Sources]
+  VariableTraditionalMmRuntimeDxe.c
   VariableSmmRuntimeDxe.c
   PrivilegePolymorphic.h
   Measurement.c
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMmRuntimeDxe.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMmRuntimeDxe.c
new file mode 100644
index 0000000..0c039f1
--- /dev/null
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMmRuntimeDxe.c
@@ -0,0 +1,42 @@
+/** @file
+
+  Parts of the SMM/MM implementation that are specific to standalone MM
+
+Copyright (c) 2019, ARM Ltd. All rights reserved.
+
+This program and the accompanying materials
+are licensed and made available under the terms and conditions of the BSD License
+which accompanies this distribution.  The full text of the license may be found at
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include "Variable.h"
+
+
+/**
+  Check whether the protocol is installed or not.
+**/
+EFI_STATUS
+EFIAPI
+VariableLocateSmmReady (
+  VOID
+  )
+{
+  return TRUE;
+}
+
+/**
+  Check whether the protocol is installed or not.
+**/
+EFI_STATUS
+EFIAPI
+VariableLocateSmmWriteReady (
+  VOID
+  )
+{
+  return TRUE;
+}
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMmRuntimeDxe.inf b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMmRuntimeDxe.inf
new file mode 100644
index 0000000..eb4cd99
--- /dev/null
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMmRuntimeDxe.inf
@@ -0,0 +1,95 @@
+## @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) 2019, ARM Ltd. All rights reserved.
+# This program and the accompanying materials
+# are licensed and made available under the terms and conditions of the BSD License
+# which accompanies this distribution. The full text of the license may be found at
+# http://opensource.org/licenses/bsd-license.php
+# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = VariableSmmRuntimeDxe
+  MODULE_UNI_FILE                = VariableSmmRuntimeDxe.uni
+  FILE_GUID                      = 64BC59FB-00AE-416A-952B-9DC1F7EA328C
+  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]
+  VariableStandaloneMmRuntimeDxe.c
+  VariableSmmRuntimeDxe.c
+  PrivilegePolymorphic.h
+  Measurement.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+
+[LibraryClasses]
+  MemoryAllocationLib
+  BaseLib
+  UefiBootServicesTableLib
+  DebugLib
+  UefiRuntimeLib
+  DxeServicesTableLib
+  UefiDriverEntryPoint
+  TpmMeasurementLib
+
+[Protocols]
+  gEfiVariableWriteArchProtocolGuid             ## PRODUCES
+  gEfiVariableArchProtocolGuid                  ## PRODUCES
+  gEfiSmmCommunicationProtocolGuid              ## CONSUMES
+  ## CONSUMES
+  ## NOTIFY
+  ## UNDEFINED # Used to do smm communication
+  gEfiSmmVariableProtocolGuid
+  gEdkiiVariableLockProtocolGuid                ## PRODUCES
+  gEdkiiVarCheckProtocolGuid                    ## PRODUCES
+
+[Guids]
+  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
+
+[Depex]
+  gEfiSmmCommunicationProtocolGuid
+
+[UserExtensions.TianoCore."ExtraFiles"]
+  VariableSmmRuntimeDxeExtra.uni
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableTraditionalMmRuntimeDxe.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableTraditionalMmRuntimeDxe.c
new file mode 100644
index 0000000..049f849
--- /dev/null
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableTraditionalMmRuntimeDxe.c
@@ -0,0 +1,45 @@
+/** @file
+
+  Parts of the SMM/MM implementation that are specific to traditional MM
+
+Copyright (c) 2019, ARM Ltd. All rights reserved.
+This program and the accompanying materials
+are licensed and made available under the terms and conditions of the BSD License
+which accompanies this distribution.  The full text of the license may be found at
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include <Protocol/SmmVariable.h>
+#include "Variable.h"
+
+EFI_SMM_VARIABLE_PROTOCOL    *mSmmVariable = NULL;
+
+/**
+  Check whether the protocol is installed or not.
+**/
+EFI_STATUS
+EFIAPI
+VariableLocateSmmReady (
+  VOID
+  )
+{
+  return gBS->LocateProtocol (&gEfiSmmVariableProtocolGuid, NULL, (VOID **)&mSmmVariable);
+}
+
+/**
+  Notify the system that the SMM variable write driver is ready.
+**/
+EFI_STATUS
+EFIAPI
+VariableLocateSmmWriteReady (
+  VOID
+  )
+{
+  VOID         *ProtocolOps;
+
+  return gBS->LocateProtocol (&gSmmVariableWriteGuid, NULL, (VOID **) &ProtocolOps);
+}
-- 
2.7.4