Re: [edk2-devel] [PATCH V2 1/9] UefiCpuPkg: Add CcExitLib

["Lendacky, Thomas" <thomas.lendacky@amd.com>]

On 11/3/22 18:19, Min Xu via groups.io wrote:
> From: Min M Xu <min.m.xu@intel.com>
> 
> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4123
> 
> CcExitLib is designed to support handling #VC/#VE exceptions and issuing
> VMGEXIT instructions. It can be used to perform these:
>    - Handling #VC exceptions
>    - Handling #VE exceptions
>    - Preparing for and issuing a VMGEXIT
>    - Performing MMIO-related write operations to support flash emulation
>    - Performing AP related boot opeations
> 
> The base functions in this driver will not do anything and will return
> an error if a return value is required. It is expected that other packages
> (like OvmfPkg) will create a version of the library to fully support an
> CC gueste (such as SEV-ES and TDX).
> 
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Ray Ni <ray.ni@intel.com>
> Cc: Brijesh Singh <brijesh.singh@amd.com>
> Cc: Erdem Aktas <erdemaktas@google.com>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Cc: James Bottomley <jejb@linux.ibm.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Tom Lendacky <thomas.lendacky@amd.com>
> Signed-off-by: Min Xu <min.m.xu@intel.com>
> ---
>   UefiCpuPkg/Include/Library/CcExitLib.h        | 176 ++++++++++++++++
>   .../Library/CcExitLibNull/CcExitLibNull.c     | 194 ++++++++++++++++++
>   .../Library/CcExitLibNull/CcExitLibNull.inf   |  28 +++
>   .../Library/CcExitLibNull/CcExitLibNull.uni   |  14 ++
>   UefiCpuPkg/UefiCpuPkg.dec                     |   3 +
>   5 files changed, 415 insertions(+)
>   create mode 100644 UefiCpuPkg/Include/Library/CcExitLib.h
>   create mode 100644 UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.c
>   create mode 100644 UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.inf
>   create mode 100644 UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.uni
> 
> diff --git a/UefiCpuPkg/Include/Library/CcExitLib.h b/UefiCpuPkg/Include/Library/CcExitLib.h
> new file mode 100644
> index 000000000000..40372e10b39e
> --- /dev/null
> +++ b/UefiCpuPkg/Include/Library/CcExitLib.h
> @@ -0,0 +1,176 @@
> +/** @file
> +  Public header file for the CcExitLib.
> +
> +  This library class defines some routines used for below CcExit handler.
> +   - Invoking the VMGEXIT instruction in support of SEV-ES and to handle
> +     #VC exceptions.
> +   - Handle #VE exception in TDX.
> +
> +  Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
> +  Copyright (c) 2020 - 2022, Intel Corporation. All rights reserved.<BR>
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#ifndef CC_EXIT_LIB_H_
> +#define CC_EXIT_LIB_H_
> +
> +#include <Protocol/DebugSupport.h>
> +#include <Register/Amd/Ghcb.h>
> +
> +#define VE_EXCEPTION  20
> +
> +/**
> +  Perform VMGEXIT.
> +
> +  Sets the necessary fields of the GHCB, invokes the VMGEXIT instruction and
> +  then handles the return actions.
> +
> +  @param[in, out]  Ghcb       A pointer to the GHCB
> +  @param[in]       ExitCode   VMGEXIT code to be assigned to the SwExitCode
> +                              field of the GHCB.
> +  @param[in]       ExitInfo1  VMGEXIT information to be assigned to the
> +                              SwExitInfo1 field of the GHCB.
> +  @param[in]       ExitInfo2  VMGEXIT information to be assigned to the
> +                              SwExitInfo2 field of the GHCB.
> +
> +  @retval  0                  VMGEXIT succeeded.
> +  @return                     Exception number to be propagated, VMGEXIT
> +                              processing did not succeed.
> +
> +**/
> +UINT64
> +EFIAPI
> +CcExitLibVmgExit (
> +  IN OUT GHCB    *Ghcb,
> +  IN     UINT64  ExitCode,
> +  IN     UINT64  ExitInfo1,
> +  IN     UINT64  ExitInfo2
> +  );
> +
> +/**
> +  Perform pre-VMGEXIT initialization/preparation.
> +
> +  Performs the necessary steps in preparation for invoking VMGEXIT. Must be
> +  called before setting any fields within the GHCB.
> +
> +  @param[in, out]  Ghcb            A pointer to the GHCB
> +  @param[in, out]  InterruptState  A pointer to hold the current interrupt
> +                                   state, used for restoring in CcExitLibVmgDone ()
> +
> +**/
> +VOID
> +EFIAPI
> +CcExitLibVmgInit (
> +  IN OUT GHCB     *Ghcb,
> +  IN OUT BOOLEAN  *InterruptState
> +  );
> +
> +/**
> +  Perform post-VMGEXIT cleanup.
> +
> +  Performs the necessary steps to cleanup after invoking VMGEXIT. Must be
> +  called after obtaining needed fields within the GHCB.
> +
> +  @param[in, out]  Ghcb            A pointer to the GHCB
> +  @param[in]       InterruptState  An indicator to conditionally (re)enable
> +                                   interrupts
> +
> +**/
> +VOID
> +EFIAPI
> +CcExitLibVmgDone (
> +  IN OUT GHCB     *Ghcb,
> +  IN     BOOLEAN  InterruptState
> +  );
> +
> +/**
> +  Marks a specified offset as valid in the GHCB.
> +
> +  The ValidBitmap area represents the areas of the GHCB that have been marked
> +  valid. Set the bit in ValidBitmap for the input offset.
> +
> +  @param[in, out]  Ghcb       A pointer to the GHCB
> +  @param[in]       Offset     Qword offset in the GHCB to mark valid
> +
> +**/
> +VOID
> +EFIAPI
> +CcExitLibVmgSetOffsetValid (
> +  IN OUT GHCB           *Ghcb,
> +  IN     GHCB_REGISTER  Offset
> +  );
> +
> +/**
> +  Checks if a specified offset is valid in the GHCB.
> +
> +  The ValidBitmap area represents the areas of the GHCB that have been marked
> +  valid. Return whether the bit in the ValidBitmap is set for the input offset.
> +
> +  @param[in]  Ghcb            A pointer to the GHCB
> +  @param[in]  Offset          Qword offset in the GHCB to mark valid
> +
> +  @retval TRUE                Offset is marked valid in the GHCB
> +  @retval FALSE               Offset is not marked valid in the GHCB
> +
> +**/
> +BOOLEAN
> +EFIAPI
> +CcExitLibVmgIsOffsetValid (
> +  IN GHCB           *Ghcb,
> +  IN GHCB_REGISTER  Offset
> +  );
> +
> +/**
> +  Handle a #VC exception.
> +
> +  Performs the necessary processing to handle a #VC exception.
> +
> +  The base library function returns an error equal to VC_EXCEPTION,
> +  to be propagated to the standard exception handling stack.
> +
> +  @param[in, out]  ExceptionType  Pointer to an EFI_EXCEPTION_TYPE to be set
> +                                  as value to use on error.
> +  @param[in, out]  SystemContext  Pointer to EFI_SYSTEM_CONTEXT
> +
> +  @retval  EFI_SUCCESS            Exception handled
> +  @retval  EFI_UNSUPPORTED        #VC not supported, (new) exception value to
> +                                  propagate provided
> +  @retval  EFI_PROTOCOL_ERROR     #VC handling failed, (new) exception value to
> +                                  propagate provided
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +CcExitHandleVc (

Sorry I didn't pick up on this before, but any reason this isn't 
CcExitLibHandleVc() to match the other APIs or have the other APIs just be 
CcExit (since the "Lib" part seems a bit excessive)?

(Same for CcExitHandleVe below)

Thanks,
Tom

> +  IN OUT EFI_EXCEPTION_TYPE  *ExceptionType,
> +  IN OUT EFI_SYSTEM_CONTEXT  SystemContext
> +  );
> +
> +/**
> +  Handle a #VE exception.
> +
> +  Performs the necessary processing to handle a #VE exception.
> +
> +  The base library function returns an error equal to VE_EXCEPTION,
> +  to be propagated to the standard exception handling stack.
> +
> +  @param[in, out]  ExceptionType  Pointer to an EFI_EXCEPTION_TYPE to be set
> +                                  as value to use on error.
> +  @param[in, out]  SystemContext  Pointer to EFI_SYSTEM_CONTEXT
> +
> +  @retval  EFI_SUCCESS            Exception handled
> +  @retval  EFI_UNSUPPORTED        #VE not supported, (new) exception value to
> +                                  propagate provided
> +  @retval  EFI_PROTOCOL_ERROR     #VE handling failed, (new) exception value to
> +                                  propagate provided
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +CcExitHandleVe (
> +  IN OUT EFI_EXCEPTION_TYPE  *ExceptionType,
> +  IN OUT EFI_SYSTEM_CONTEXT  SystemContext
> +  );
> +
> +#endif
> diff --git a/UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.c b/UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.c
> new file mode 100644
> index 000000000000..bd23793f1e04
> --- /dev/null
> +++ b/UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.c
> @@ -0,0 +1,194 @@
> +/** @file
> +  CcExit Base Support Library.
> +
> +  Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
> +  Copyright (c) 2020 - 2022, Intel Corporation. All rights reserved.<BR>
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <Base.h>
> +#include <Uefi.h>
> +#include <Library/CcExitLib.h>
> +
> +/**
> +  Perform VMGEXIT.
> +
> +  Sets the necessary fields of the GHCB, invokes the VMGEXIT instruction and
> +  then handles the return actions.
> +
> +  The base library function returns an error in the form of a
> +  GHCB_EVENT_INJECTION representing a GP_EXCEPTION.
> +
> +  @param[in, out]  Ghcb       A pointer to the GHCB
> +  @param[in]       ExitCode   VMGEXIT code to be assigned to the SwExitCode
> +                              field of the GHCB.
> +  @param[in]       ExitInfo1  VMGEXIT information to be assigned to the
> +                              SwExitInfo1 field of the GHCB.
> +  @param[in]       ExitInfo2  VMGEXIT information to be assigned to the
> +                              SwExitInfo2 field of the GHCB.
> +
> +  @retval  0                  VMGEXIT succeeded.
> +  @return                     Exception number to be propagated, VMGEXIT
> +                              processing did not succeed.
> +
> +**/
> +UINT64
> +EFIAPI
> +CcExitLibVmgExit (
> +  IN OUT GHCB    *Ghcb,
> +  IN     UINT64  ExitCode,
> +  IN     UINT64  ExitInfo1,
> +  IN     UINT64  ExitInfo2
> +  )
> +{
> +  GHCB_EVENT_INJECTION  Event;
> +
> +  Event.Uint64          = 0;
> +  Event.Elements.Vector = GP_EXCEPTION;
> +  Event.Elements.Type   = GHCB_EVENT_INJECTION_TYPE_EXCEPTION;
> +  Event.Elements.Valid  = 1;
> +
> +  return Event.Uint64;
> +}
> +
> +/**
> +  Perform pre-VMGEXIT initialization/preparation.
> +
> +  Performs the necessary steps in preparation for invoking VMGEXIT. Must be
> +  called before setting any fields within the GHCB.
> +
> +  @param[in, out]  Ghcb            A pointer to the GHCB
> +  @param[in, out]  InterruptState  A pointer to hold the current interrupt
> +                                   state, used for restoring in CcExitLibVmgDone ()
> +
> +**/
> +VOID
> +EFIAPI
> +CcExitLibVmgInit (
> +  IN OUT GHCB     *Ghcb,
> +  IN OUT BOOLEAN  *InterruptState
> +  )
> +{
> +}
> +
> +/**
> +  Perform post-VMGEXIT cleanup.
> +
> +  Performs the necessary steps to cleanup after invoking VMGEXIT. Must be
> +  called after obtaining needed fields within the GHCB.
> +
> +  @param[in, out]  Ghcb            A pointer to the GHCB
> +  @param[in]       InterruptState  An indicator to conditionally (re)enable
> +                                   interrupts
> +
> +**/
> +VOID
> +EFIAPI
> +CcExitLibVmgDone (
> +  IN OUT GHCB     *Ghcb,
> +  IN     BOOLEAN  InterruptState
> +  )
> +{
> +}
> +
> +/**
> +  Marks a field at the specified offset as valid in the GHCB.
> +
> +  The ValidBitmap area represents the areas of the GHCB that have been marked
> +  valid. Set the bit in ValidBitmap for the input offset.
> +
> +  @param[in, out] Ghcb    Pointer to the Guest-Hypervisor Communication Block
> +  @param[in]      Offset  Qword offset in the GHCB to mark valid
> +
> +**/
> +VOID
> +EFIAPI
> +CcExitLibVmgSetOffsetValid (
> +  IN OUT GHCB           *Ghcb,
> +  IN     GHCB_REGISTER  Offset
> +  )
> +{
> +}
> +
> +/**
> +  Checks if a specified offset is valid in the GHCB.
> +
> +  The ValidBitmap area represents the areas of the GHCB that have been marked
> +  valid. Return whether the bit in the ValidBitmap is set for the input offset.
> +
> +  @param[in]  Ghcb            A pointer to the GHCB
> +  @param[in]  Offset          Qword offset in the GHCB to mark valid
> +
> +  @retval TRUE                Offset is marked valid in the GHCB
> +  @retval FALSE               Offset is not marked valid in the GHCB
> +
> +**/
> +BOOLEAN
> +EFIAPI
> +CcExitLibVmgIsOffsetValid (
> +  IN GHCB           *Ghcb,
> +  IN GHCB_REGISTER  Offset
> +  )
> +{
> +  return FALSE;
> +}
> +
> +/**
> +  Handle a #VC exception.
> +
> +  Performs the necessary processing to handle a #VC exception.
> +
> +  The base library function returns an error equal to VC_EXCEPTION,
> +  to be propagated to the standard exception handling stack.
> +
> +  @param[in, out]  ExceptionType  Pointer to an EFI_EXCEPTION_TYPE to be set
> +                                  as value to use on error.
> +  @param[in, out]  SystemContext  Pointer to EFI_SYSTEM_CONTEXT
> +
> +  @retval  EFI_SUCCESS            Exception handled
> +  @retval  EFI_UNSUPPORTED        #VC not supported, (new) exception value to
> +                                  propagate provided
> +  @retval  EFI_PROTOCOL_ERROR     #VC handling failed, (new) exception value to
> +                                  propagate provided
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +CcExitHandleVc (
> +  IN OUT EFI_EXCEPTION_TYPE  *ExceptionType,
> +  IN OUT EFI_SYSTEM_CONTEXT  SystemContext
> +  )
> +{
> +  *ExceptionType = VC_EXCEPTION;
> +
> +  return EFI_UNSUPPORTED;
> +}
> +
> +/**
> +  Handle a #VE exception.
> +
> +  Performs the necessary processing to handle a #VE exception.
> +
> +  @param[in, out]  ExceptionType  Pointer to an EFI_EXCEPTION_TYPE to be set
> +                                  as value to use on error.
> +  @param[in, out]  SystemContext  Pointer to EFI_SYSTEM_CONTEXT
> +
> +  @retval  EFI_SUCCESS            Exception handled
> +  @retval  EFI_UNSUPPORTED        #VE not supported, (new) exception value to
> +                                  propagate provided
> +  @retval  EFI_PROTOCOL_ERROR     #VE handling failed, (new) exception value to
> +                                  propagate provided
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +CcExitHandleVe (
> +  IN OUT EFI_EXCEPTION_TYPE  *ExceptionType,
> +  IN OUT EFI_SYSTEM_CONTEXT  SystemContext
> +  )
> +{
> +  *ExceptionType = VE_EXCEPTION;
> +
> +  return EFI_UNSUPPORTED;
> +}
> diff --git a/UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.inf b/UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.inf
> new file mode 100644
> index 000000000000..c1f53e42dbe4
> --- /dev/null
> +++ b/UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.inf
> @@ -0,0 +1,28 @@
> +## @file
> +#  CcExit Base Support Library.
> +#
> +#  Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
> +#  Copyright (c) 2020 - 2022, Intel Corporation. All rights reserved.<BR>
> +#  SPDX-License-Identifier: BSD-2-Clause-Patent
> +#
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 0x00010005
> +  BASE_NAME                      = CcExitLibNull
> +  MODULE_UNI_FILE                = CcExitLibNull.uni
> +  FILE_GUID                      = 4029bbf2-ed6c-4cf6-ac17-a0213684ae41
> +  MODULE_TYPE                    = BASE
> +  VERSION_STRING                 = 1.0
> +  LIBRARY_CLASS                  = CcExitLib
> +
> +[Sources.common]
> +  CcExitLibNull.c
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +  UefiCpuPkg/UefiCpuPkg.dec
> +
> +[LibraryClasses]
> +  BaseLib
> +
> diff --git a/UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.uni b/UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.uni
> new file mode 100644
> index 000000000000..b18ae8792ed7
> --- /dev/null
> +++ b/UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.uni
> @@ -0,0 +1,14 @@
> +// /** @file
> +// CcExitLib instance.
> +//
> +// Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
> +// Copyright (c) 2020 - 2022, Intel Corporation. All rights reserved.<BR>
> +// SPDX-License-Identifier: BSD-2-Clause-Patent
> +//
> +// **/
> +
> +
> +#string STR_MODULE_ABSTRACT             #language en-US "CcExitLib NULL instance"
> +
> +#string STR_MODULE_DESCRIPTION          #language en-US "CcExitLib NULL instance."
> +
> diff --git a/UefiCpuPkg/UefiCpuPkg.dec b/UefiCpuPkg/UefiCpuPkg.dec
> index 718323d9042c..8058b679412f 100644
> --- a/UefiCpuPkg/UefiCpuPkg.dec
> +++ b/UefiCpuPkg/UefiCpuPkg.dec
> @@ -56,6 +56,9 @@
>     ##  @libraryclass  Provides function to support VMGEXIT processing.
>     VmgExitLib|Include/Library/VmgExitLib.h
>   
> +  ##  @libraryclass  Provides function to support CcExit processing.
> +  CcExitLib|Include/Library/CcExitLib.h
> +
>     ##  @libraryclass  Provides function to get CPU cache information.
>     CpuCacheInfoLib|Include/Library/CpuCacheInfoLib.h
>