Re: [edk2-devel] [PATCH v1 3/3] DynamicTablesPkg: Adds ACPI WSMT Table generator

["PierreGondois" <pierre.gondois@arm.com>]

Hello Abdul,
I reviewed this patch first, so comments here may apply to other patches.

---

AcpiView (ShellPkg/Library/UefiShellAcpiViewCommandLib) doesn't seem
to be able to parse this ACPI table. Maybe a parser could also be added
along with the table generation.


On 2/20/24 07:48, Abdul Lateef Attar wrote:
> From: Abdul Lateef Attar <AbdulLateef.Attar@amd.com>
> 
> Adds generic ACPI WSMT table generator library.
> Register/Deregister WSMT table.
> Update the WSMT table during boot as per specification.
> 
> Cc: Sami Mujawar <Sami.Mujawar@arm.com>
> Cc: Pierre Gondois <pierre.gondois@arm.com>
> Signed-off-by: Abdul Lateef Attar <AbdulLateef.Attar@amd.com>
> ---
>   DynamicTablesPkg/DynamicTables.dsc.inc        |   2 +
>   DynamicTablesPkg/Include/AcpiTableGenerator.h |   1 +
>   .../Include/ArchNameSpaceObjects.h            |  10 +
>   .../Library/Acpi/AcpiWsmtLib/AcpiWsmtLib.inf  |  34 +++
>   .../Library/Acpi/AcpiWsmtLib/WsmtGenerator.c  | 221 ++++++++++++++++++
>   5 files changed, 268 insertions(+)
>   create mode 100644 DynamicTablesPkg/Library/Acpi/AcpiWsmtLib/AcpiWsmtLib.inf
>   create mode 100644 DynamicTablesPkg/Library/Acpi/AcpiWsmtLib/WsmtGenerator.c
> 
> diff --git a/DynamicTablesPkg/DynamicTables.dsc.inc b/DynamicTablesPkg/DynamicTables.dsc.inc
> index af70785520..5e66f5cd02 100644
> --- a/DynamicTablesPkg/DynamicTables.dsc.inc
> +++ b/DynamicTablesPkg/DynamicTables.dsc.inc
> @@ -36,6 +36,7 @@
>     #
>     DynamicTablesPkg/Library/Acpi/AcpiFadtLib/AcpiFadtLib.inf
>     DynamicTablesPkg/Library/Acpi/AcpiHpetLib/AcpiHpetLib.inf
> +  DynamicTablesPkg/Library/Acpi/AcpiWsmtLib/AcpiWsmtLib.inf
>   
>     #
>     # Dynamic Table Factory Dxe
> @@ -44,6 +45,7 @@
>       <LibraryClasses>
>         NULL|DynamicTablesPkg/Library/Acpi/AcpiFadtLib/AcpiFadtLib.inf
>         NULL|DynamicTablesPkg/Library/Acpi/AcpiHpetLib/AcpiHpetLib.inf
> +      NULL|DynamicTablesPkg/Library/Acpi/AcpiWsmtLib/AcpiWsmtLib.inf

The table should be available for all architectures right ?
This should not be in a [Components] section instead of a more limiting
[Components.IA32, Components.X64] section I assume.

>     }
>   
>   [Components.ARM, Components.AARCH64]
> diff --git a/DynamicTablesPkg/Include/AcpiTableGenerator.h b/DynamicTablesPkg/Include/AcpiTableGenerator.h
> index 18b5f99f47..a32ef46ecb 100644
> --- a/DynamicTablesPkg/Include/AcpiTableGenerator.h
> +++ b/DynamicTablesPkg/Include/AcpiTableGenerator.h
> @@ -100,6 +100,7 @@ typedef enum StdAcpiTableId {
>     EStdAcpiTableIdSsdtPciExpress,                ///< SSDT Pci Express Generator
>     EStdAcpiTableIdPcct,                          ///< PCCT Generator
>     EStdAcpiTableIdHpet,                          ///< HPET Generator
> +  EStdAcpiTableIdWsmt,                          ///< WSMT Generator
>     EStdAcpiTableIdMax
>   } ESTD_ACPI_TABLE_ID;
>   
> diff --git a/DynamicTablesPkg/Include/ArchNameSpaceObjects.h b/DynamicTablesPkg/Include/ArchNameSpaceObjects.h
> index b421c4cd29..ad3045dfec 100644
> --- a/DynamicTablesPkg/Include/ArchNameSpaceObjects.h
> +++ b/DynamicTablesPkg/Include/ArchNameSpaceObjects.h
> @@ -39,6 +39,7 @@ typedef enum ArchObjectID {
>     EArchObjFadtArmBootArch,        ///< 11 - ARM boot arch information
>     EArchObjFadtHypervisorVendorId, ///< 12 - Hypervisor vendor identity information
>     EArchObjFadtMiscInfo,           ///< 13 - Legacy fields; RTC, latency, flush stride, etc
> +  EArchObjWsmtProtectionFlags,    ///< 14 - WSMT protection flags
>     EArchObjMax
>   } E_ARCH_OBJECT_ID;
>   
> @@ -214,4 +215,13 @@ typedef struct CmArchFadtMiscInfo {
>     UINT8     Century;
>   } CM_ARCH_FADT_MISC_INFO;
>   
> +/** A structure that describes the
> +    protection flags for the WSMT fields information.
> +
> +    ID: EArchObjWsmtProtectionFlags
> +*/
> +typedef struct CmArchWsmtProtectionFlags {
> +  UINT32    ProtectionFlags;
> +} CM_ARCH_WSMT_PROTECTION_FLAGS;
> +

There is an ongoing effort to open the package a bit more to other
architectures (https://edk2.groups.io/g/devel/message/114790).
The common Arch namespace will be created in the (to be created) staging
branch.

Maybe we could add the object to the Arm namespace for now ?
Sami, what do you think ?

>   #endif
> diff --git a/DynamicTablesPkg/Library/Acpi/AcpiWsmtLib/AcpiWsmtLib.inf b/DynamicTablesPkg/Library/Acpi/AcpiWsmtLib/AcpiWsmtLib.inf
> new file mode 100644
> index 0000000000..f8683a5005
> --- /dev/null
> +++ b/DynamicTablesPkg/Library/Acpi/AcpiWsmtLib/AcpiWsmtLib.inf
> @@ -0,0 +1,34 @@
> +## @file
> +#  WSMT Table Generator
> +#
> +#  Copyright (C) 2024 Advanced Micro Devices, Inc. All rights reserved.
> +#
> +#  SPDX-License-Identifier: BSD-2-Clause-Patent
> +##
> +
> +[Defines]
> +  INF_VERSION    = 1.27
> +  BASE_NAME      = AcpiWsmtLib
> +  FILE_GUID      = D6C34086-C914-4F8E-B56A-08329B4D1271
> +  VERSION_STRING = 1.0
> +  MODULE_TYPE    = DXE_DRIVER
> +  LIBRARY_CLASS  = NULL|DXE_DRIVER
> +  CONSTRUCTOR    = AcpiWsmtLibConstructor
> +  DESTRUCTOR     = AcpiWsmtLibDestructor
> +
> +[Sources]
> +  WsmtGenerator.c
> +
> +[Packages]
> +  DynamicTablesPkg/DynamicTablesPkg.dec
> +  MdeModulePkg/MdeModulePkg.dec
> +  MdePkg/MdePkg.dec
> +
> +[LibraryClasses]
> +  BaseLib
> +  DebugLib
> +  PcdLib
> +
> +[Pcd]
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiDefaultCreatorId
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiDefaultCreatorRevision
> diff --git a/DynamicTablesPkg/Library/Acpi/AcpiWsmtLib/WsmtGenerator.c b/DynamicTablesPkg/Library/Acpi/AcpiWsmtLib/WsmtGenerator.c
> new file mode 100644
> index 0000000000..c102152974
> --- /dev/null
> +++ b/DynamicTablesPkg/Library/Acpi/AcpiWsmtLib/WsmtGenerator.c
> @@ -0,0 +1,221 @@
> +/** @file
> +  WSMT Table Generator
> +
> +  Copyright (c) 2017 - 2023, Arm Limited. All rights reserved.
> +  Copyright (C) 2024 Advanced Micro Devices, Inc. All rights reserved.
> +
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +  @par Reference(s):
> +  - ACPI 6.5 Specification, Aug 29, 2022
> +  - WSMT spec, version 1.0, April 18, 2016
> +
> +**/
> +
> +#include <AcpiTableGenerator.h>
> +#include <ConfigurationManagerHelper.h>
> +#include <ConfigurationManagerObject.h>
> +#include <IndustryStandard/WindowsSmmSecurityMitigationTable.h>
> +#include <Library/DebugLib.h>
> +#include <Library/TableHelperLib.h>
> +#include <Protocol/ConfigurationManagerProtocol.h>

> +#include <Uefi/UefiBaseType.h>
> +#include <Uefi/UefiSpec.h>

These 2 includes don't seem to be necessary.

> +#include <ArchNameSpaceObjects.h>
> +
> +/** This macro expands to a function that retrieves the
> +    protection flags information for WSMT Table.
> +*/
> +GET_OBJECT_LIST (
> +  EObjNameSpaceArch,
> +  EArchObjWsmtProtectionFlags,
> +  CM_ARCH_WSMT_PROTECTION_FLAGS
> +  );
> +
> +/** The AcpiWsmt is a template EFI_ACPI_WSMT_TABLE
> +    structure used for generating the WSMT Table.
> +*/
> +STATIC
> +EFI_ACPI_WSMT_TABLE  mAcpiWsmt = {
> +  ACPI_HEADER (
> +    EFI_ACPI_WINDOWS_SMM_SECURITY_MITIGATION_TABLE_SIGNATURE,
> +    EFI_ACPI_WSMT_TABLE,
> +    EFI_WSMT_TABLE_REVISION
> +    ),
> +  EFI_WSMT_PROTECTION_FLAGS_SYSTEM_RESOURCE_PROTECTION|EFI_WSMT_PROTECTION_FLAGS_COMM_BUFFER_NESTED_PTR_PROTECTION|EFI_WSMT_PROTECTION_FLAGS_FIXED_COMM_BUFFERS

I think there is a 100 chars limit. It could be compacted with a macro (like):

#define WSMT_DEFAULT_PROTECTION_FLAGS 					\
	EFI_WSMT_PROTECTION_FLAGS_SYSTEM_RESOURCE_PROTECTION 		\
	EFI_WSMT_PROTECTION_FLAGS_COMM_BUFFER_NESTED_PTR_PROTECTION	\
	EFI_WSMT_PROTECTION_FLAGS_FIXED_COMM_BUFFERS


> +};
> +
> +/** Construct the WSMT table.
> +
> +  This function invokes the Configuration Manager protocol interface
> +  to get the required hardware information for generating the ACPI
> +  table.
> +
> +  If this function allocates any resources then they must be freed
> +  in the FreeXXXXTableResources function.
> +
> +  @param [in]  This           Pointer to the table generator.
> +  @param [in]  AcpiTableInfo  Pointer to the ACPI Table Info.
> +  @param [in]  CfgMgrProtocol Pointer to the Configuration Manager
> +                              Protocol Interface.
> +  @param [out] Table          Pointer to the constructed ACPI Table.
> +
> +  @retval EFI_SUCCESS           Table generated successfully.
> +  @retval EFI_INVALID_PARAMETER A parameter is invalid.
> +  @retval EFI_NOT_FOUND         The required object was not found.
> +  @retval EFI_BAD_BUFFER_SIZE   The size returned by the Configuration
> +                                Manager is less than the Object size for the
> +                                requested object.
> +**/
> +STATIC
> +EFI_STATUS
> +BuildWsmtTable (
> +  IN  CONST ACPI_TABLE_GENERATOR                  *CONST  This,
> +  IN  CONST CM_STD_OBJ_ACPI_TABLE_INFO            *CONST  AcpiTableInfo,
> +  IN  CONST EDKII_CONFIGURATION_MANAGER_PROTOCOL  *CONST  CfgMgrProtocol,
> +  OUT       EFI_ACPI_DESCRIPTION_HEADER          **CONST  Table
> +  )
> +{
> +  EFI_STATUS                     Status;
> +  CM_ARCH_WSMT_PROTECTION_FLAGS  *ProtectionFlags;
> +
> +  ASSERT (This != NULL);
> +  ASSERT (AcpiTableInfo != NULL);
> +  ASSERT (CfgMgrProtocol != NULL);
> +  ASSERT (Table != NULL);
> +  ASSERT (AcpiTableInfo->TableGeneratorId == This->GeneratorID);
> +  ASSERT (AcpiTableInfo->AcpiTableSignature == This->AcpiTableSignature);
> +
> +  if ((AcpiTableInfo->AcpiTableRevision < This->MinAcpiTableRevision) ||
> +      (AcpiTableInfo->AcpiTableRevision > This->AcpiTableRevision))
> +  {
> +    DEBUG ((
> +      DEBUG_ERROR,
> +      "ERROR: WSMT: Requested table revision = %d, is not supported."
> +      "Supported table revision: Minimum = %d, Maximum = %d\n",
> +      AcpiTableInfo->AcpiTableRevision,
> +      This->MinAcpiTableRevision,
> +      This->AcpiTableRevision
> +      ));
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  *Table = NULL;
> +
> +  Status = AddAcpiHeader (
> +             CfgMgrProtocol,
> +             This,
> +             (EFI_ACPI_DESCRIPTION_HEADER *)&mAcpiWsmt,
> +             AcpiTableInfo,
> +             sizeof (EFI_ACPI_WSMT_TABLE)
> +             );
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((
> +      DEBUG_ERROR,
> +      "ERROR: WSMT: Failed to add ACPI header. Status = %r\n",
> +      Status
> +      ));
> +    return Status;
> +  }
> +
> +  Status = GetEArchObjWsmtProtectionFlags (
> +             CfgMgrProtocol,
> +             CM_NULL_TOKEN,
> +             &ProtectionFlags,
> +             NULL
> +             );
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((
> +      DEBUG_ERROR,
> +      "ERROR: WSMT: Failed to get protection flags information." \
> +      " Status = %r\n",
> +      Status
> +      ));
> +  } else {
> +    mAcpiWsmt.ProtectionFlags = ProtectionFlags->ProtectionFlags;
> +  }

It seems that EFI_WSMT_PROTECTION_FLAGS_COMM_BUFFER_NESTED_PTR_PROTECTION
bit can only be set if EFI_WSMT_PROTECTION_FLAGS_FIXED_COMM_BUFFERS
is set. Maybe this should be checked here.


> +
> +  *Table = (EFI_ACPI_DESCRIPTION_HEADER *)&mAcpiWsmt;
> +
> +  return Status;
> +}
> +
> +/** The interface for the WSMT Table Generator.
> +*/
> +STATIC
> +CONST
> +ACPI_TABLE_GENERATOR  mWsmtGenerator = {
> +  // Generator ID
> +  CREATE_STD_ACPI_TABLE_GEN_ID (EStdAcpiTableIdWsmt),
> +  // Generator Description
> +  L"ACPI.STD.WSMT.GENERATOR",
> +  // ACPI Table Signature
> +  EFI_ACPI_WINDOWS_SMM_SECURITY_MITIGATION_TABLE_SIGNATURE,
> +  // ACPI Table Revision supported by this Generator
> +  EFI_WSMT_TABLE_REVISION,
> +  // Minimum supported ACPI Table Revision
> +  EFI_WSMT_TABLE_REVISION,
> +  // Creator ID
> +  FixedPcdGet32 (PcdAcpiDefaultCreatorId),

The Creator Id should be, from the ACPI spec:
"""
The vendor ID of the utility that created the table
"""
and/or:
"""
Vendor ID of utility that created the table. For tables
containing Definition Blocks, this is the ID for the ASL
Compiler.
"""

As the DynamicTables framework is creating the tables, a value
representing that should be used. Other generators use:
   #define TABLE_GENERATOR_CREATOR_ID_ARM  SIGNATURE_32('A', 'R', 'M', 'H')
but this might be wrong to use this.

It might be necessary to either:
- Change the creator Id for all tables and update for instance:
   #define TABLE_GENERATOR_CREATOR_ID  SIGNATURE_32('D', 'Y', 'N', 'T')
- Create a Pcd

> +  // Creator Revision
> +  FixedPcdGet32 (PcdAcpiDefaultCreatorRevision),

Similar remark for the Creator Revision:
I think it should dependent on this present generator and
not be common to all generators. This would allow to identify
which version of the DynamicTables Generator created the table.

> +  // Build Table function
> +  BuildWsmtTable,
> +  // No additional resources are allocated by the generator.
> +  // Hence the Free Resource function is not required.
> +  NULL,
> +  // Extended build function not needed
> +  NULL,
> +  // Extended build function not implemented by the generator.
> +  // Hence extended free resource function is not required.
> +  NULL
> +};
> +
> +/** Register the Generator with the ACPI Table Factory.
> +
> +  @param [in]  ImageHandle  The handle to the image.
> +  @param [in]  SystemTable  Pointer to the System Table.
> +
> +  @retval EFI_SUCCESS           The Generator is registered.
> +  @retval EFI_INVALID_PARAMETER A parameter is invalid.
> +  @retval EFI_ALREADY_STARTED   The Generator for the Table ID
> +                                is already registered.
> +**/
> +EFI_STATUS
> +EFIAPI
> +AcpiWsmtLibConstructor (
> +  IN  EFI_HANDLE        ImageHandle,
> +  IN  EFI_SYSTEM_TABLE  *SystemTable
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  Status = RegisterAcpiTableGenerator (&mWsmtGenerator);
> +  DEBUG ((DEBUG_INFO, "WSMT: Register Generator. Status = %r\n", Status));
> +  ASSERT_EFI_ERROR (Status);
> +  return Status;
> +}
> +
> +/** Deregister the Generator from the ACPI Table Factory.
> +
> +  @param [in]  ImageHandle  The handle to the image.
> +  @param [in]  SystemTable  Pointer to the System Table.
> +
> +  @retval EFI_SUCCESS           The Generator is deregistered.
> +  @retval EFI_INVALID_PARAMETER A parameter is invalid.
> +  @retval EFI_NOT_FOUND         The Generator is not registered.
> +**/
> +EFI_STATUS
> +EFIAPI
> +AcpiWsmtLibDestructor (
> +  IN  EFI_HANDLE        ImageHandle,
> +  IN  EFI_SYSTEM_TABLE  *SystemTable
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  Status = DeregisterAcpiTableGenerator (&mWsmtGenerator);
> +  DEBUG ((DEBUG_INFO, "WSMT: Deregister Generator. Status = %r\n", Status));
> +  ASSERT_EFI_ERROR (Status);
> +  return Status;
> +}


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