Re: [PATCH V3 2/3] UefiCpuPkg/SmmCpuFeaturesLib: Abstract arch dependent code

["Ni, Ray" <ray.ni@intel.com>]

Reviewed-by: Ray Ni <ray.ni@intel.com>

> -----Original Message-----
> From: abner.chang@amd.com <abner.chang@amd.com>
> Sent: Monday, October 31, 2022 10:49 AM
> To: devel@edk2.groups.io
> Cc: Abdul Lateef Attar <abdattar@amd.com>; Garrett Kirkendall
> <garrett.kirkendall@amd.com>; Paul Grimes <paul.grimes@amd.com>; Dong,
> Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>; Kumar, Rahul R
> <rahul.r.kumar@intel.com>
> Subject: [PATCH V3 2/3] UefiCpuPkg/SmmCpuFeaturesLib: Abstract arch
> dependent code
> 
> From: Abner Chang <abner.chang@amd.com>
> 
> BZ# 4093: Abstract SmmCpuFeaturesLib for sharing common code
> 
> This change stripped away the code that can be
> shared with other archs or vendors from Intel
> implementation and put in to the common file,
> leaves the Intel X86 implementation in the
> IntelSmmCpuFeatureLib. Also updates the header
> file and INF file.
> 
> Signed-off-by: Abner Chang <abner.chang@amd.com>
> Cc: Abdul Lateef Attar <abdattar@amd.com>
> Cc: Garrett Kirkendall <garrett.kirkendall@amd.com>
> Cc: Paul Grimes <paul.grimes@amd.com>
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Ray Ni <ray.ni@intel.com>
> Cc: Rahul Kumar <rahul1.kumar@intel.com>
> ---
>  .../SmmCpuFeaturesLib/SmmCpuFeaturesLib.inf   |   1 +
>  .../SmmCpuFeaturesLibStm.inf                  |   1 +
>  .../StandaloneMmCpuFeaturesLib.inf            |   1 +
>  .../SmmCpuFeaturesLib/CpuFeaturesLib.h        |   6 +
>  .../IntelSmmCpuFeaturesLib.c                  | 206 +----------------
>  .../SmmCpuFeaturesLibCommon.c                 | 216 ++++++++++++++++++
>  6 files changed, 227 insertions(+), 204 deletions(-)
>  create mode 100644
> UefiCpuPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLibCommon.c
> 
> diff --git a/UefiCpuPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.inf
> b/UefiCpuPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.inf
> index 6254a14698a..9ac7dde78f8 100644
> --- a/UefiCpuPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.inf
> +++ b/UefiCpuPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.inf
> @@ -20,6 +20,7 @@
>    CpuFeaturesLib.h
>    IntelSmmCpuFeaturesLib.c
>    SmmCpuFeaturesLib.c
> +  SmmCpuFeaturesLibCommon.c
>    SmmCpuFeaturesLibNoStm.c
>    TraditionalMmCpuFeaturesLib.c
> 
> diff --git
> a/UefiCpuPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLibStm.inf
> b/UefiCpuPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLibStm.inf
> index d64d8e66b38..86d367e0a09 100644
> --- a/UefiCpuPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLibStm.inf
> +++ b/UefiCpuPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLibStm.inf
> @@ -20,6 +20,7 @@
>  [Sources]
>    CpuFeaturesLib.h
>    IntelSmmCpuFeaturesLib.c
> +  SmmCpuFeaturesLibCommon.c
>    SmmStm.c
>    SmmStm.h
>    TraditionalMmCpuFeaturesLib.c
> diff --git
> a/UefiCpuPkg/Library/SmmCpuFeaturesLib/StandaloneMmCpuFeaturesLib.i
> nf
> b/UefiCpuPkg/Library/SmmCpuFeaturesLib/StandaloneMmCpuFeaturesLib.i
> nf
> index 5935b3e1fd6..b1f60a55055 100644
> ---
> a/UefiCpuPkg/Library/SmmCpuFeaturesLib/StandaloneMmCpuFeaturesLib.i
> nf
> +++
> b/UefiCpuPkg/Library/SmmCpuFeaturesLib/StandaloneMmCpuFeaturesLib.i
> nf
> @@ -21,6 +21,7 @@
>  [Sources]
>    CpuFeaturesLib.h
>    IntelSmmCpuFeaturesLib.c
> +  SmmCpuFeaturesLibCommon.c
>    StandaloneMmCpuFeaturesLib.c
>    SmmCpuFeaturesLibNoStm.c
> 
> diff --git a/UefiCpuPkg/Library/SmmCpuFeaturesLib/CpuFeaturesLib.h
> b/UefiCpuPkg/Library/SmmCpuFeaturesLib/CpuFeaturesLib.h
> index 8a1c2adc5c4..fd3e902547c 100644
> --- a/UefiCpuPkg/Library/SmmCpuFeaturesLib/CpuFeaturesLib.h
> +++ b/UefiCpuPkg/Library/SmmCpuFeaturesLib/CpuFeaturesLib.h
> @@ -9,6 +9,12 @@
>  #ifndef CPU_FEATURES_LIB_H_
>  #define CPU_FEATURES_LIB_H_
> 
> +#include <Library/SmmCpuFeaturesLib.h>
> +#include <Library/BaseLib.h>
> +#include <Library/PcdLib.h>
> +#include <Library/MemoryAllocationLib.h>
> +#include <Library/DebugLib.h>
> +
>  /**
>    Performs library initialization.
> 
> diff --git
> a/UefiCpuPkg/Library/SmmCpuFeaturesLib/IntelSmmCpuFeaturesLib.c
> b/UefiCpuPkg/Library/SmmCpuFeaturesLib/IntelSmmCpuFeaturesLib.c
> index 75a0ec8e948..cb4897b21e3 100644
> --- a/UefiCpuPkg/Library/SmmCpuFeaturesLib/IntelSmmCpuFeaturesLib.c
> +++ b/UefiCpuPkg/Library/SmmCpuFeaturesLib/IntelSmmCpuFeaturesLib.c
> @@ -7,16 +7,11 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
> 
>  **/
> 
> -#include <PiMm.h>
> -#include <Library/SmmCpuFeaturesLib.h>
> -#include <Library/BaseLib.h>
> +#include "CpuFeaturesLib.h"
> +
>  #include <Library/MtrrLib.h>
> -#include <Library/PcdLib.h>
> -#include <Library/MemoryAllocationLib.h>
> -#include <Library/DebugLib.h>
>  #include <Register/Intel/Cpuid.h>
>  #include <Register/Intel/SmramSaveStateMap.h>
> -#include "CpuFeaturesLib.h"
> 
>  //
>  // Machine Specific Registers (MSRs)
> @@ -287,64 +282,6 @@ SmmCpuFeaturesInitializeProcessor (
>    FinishSmmCpuFeaturesInitializeProcessor ();
>  }
> 
> -/**
> -  This function updates the SMRAM save state on the currently executing
> CPU
> -  to resume execution at a specific address after an RSM instruction.  This
> -  function must evaluate the SMRAM save state to determine the execution
> mode
> -  the RSM instruction resumes and update the resume execution address
> with
> -  either NewInstructionPointer32 or NewInstructionPoint.  The auto HALT
> restart
> -  flag in the SMRAM save state must always be cleared.  This function returns
> -  the value of the instruction pointer from the SMRAM save state that was
> -  replaced.  If this function returns 0, then the SMRAM save state was not
> -  modified.
> -
> -  This function is called during the very first SMI on each CPU after
> -  SmmCpuFeaturesInitializeProcessor() to set a flag in normal execution
> mode
> -  to signal that the SMBASE of each CPU has been updated before the
> default
> -  SMBASE address is used for the first SMI to the next CPU.
> -
> -  @param[in] CpuIndex                 The index of the CPU to hook.  The value
> -                                      must be between 0 and the NumberOfCpus
> -                                      field in the System Management System Table
> -                                      (SMST).
> -  @param[in] CpuState                 Pointer to SMRAM Save State Map for the
> -                                      currently executing CPU.
> -  @param[in] NewInstructionPointer32  Instruction pointer to use if
> resuming to
> -                                      32-bit execution mode from 64-bit SMM.
> -  @param[in] NewInstructionPointer    Instruction pointer to use if resuming
> to
> -                                      same execution mode as SMM.
> -
> -  @retval 0    This function did modify the SMRAM save state.
> -  @retval > 0  The original instruction pointer value from the SMRAM save
> state
> -               before it was replaced.
> -**/
> -UINT64
> -EFIAPI
> -SmmCpuFeaturesHookReturnFromSmm (
> -  IN UINTN                 CpuIndex,
> -  IN SMRAM_SAVE_STATE_MAP  *CpuState,
> -  IN UINT64                NewInstructionPointer32,
> -  IN UINT64                NewInstructionPointer
> -  )
> -{
> -  return 0;
> -}
> -
> -/**
> -  Hook point in normal execution mode that allows the one CPU that was
> elected
> -  as monarch during System Management Mode initialization to perform
> additional
> -  initialization actions immediately after all of the CPUs have processed their
> -  first SMI and called SmmCpuFeaturesInitializeProcessor() relocating
> SMBASE
> -  into a buffer in SMRAM and called
> SmmCpuFeaturesHookReturnFromSmm().
> -**/
> -VOID
> -EFIAPI
> -SmmCpuFeaturesSmmRelocationComplete (
> -  VOID
> -  )
> -{
> -}
> -
>  /**
>    Determines if MTRR registers must be configured to set SMRAM cache-
> ability
>    when executing in System Management Mode.
> @@ -414,48 +351,6 @@ SmmCpuFeaturesRendezvousEntry (
>    }
>  }
> 
> -/**
> -  Processor specific hook point each time a CPU exits System Management
> Mode.
> -
> -  @param[in] CpuIndex  The index of the CPU that is exiting SMM.  The value
> must
> -                       be between 0 and the NumberOfCpus field in the System
> -                       Management System Table (SMST).
> -**/
> -VOID
> -EFIAPI
> -SmmCpuFeaturesRendezvousExit (
> -  IN UINTN  CpuIndex
> -  )
> -{
> -}
> -
> -/**
> -  Check to see if an SMM register is supported by a specified CPU.
> -
> -  @param[in] CpuIndex  The index of the CPU to check for SMM register
> support.
> -                       The value must be between 0 and the NumberOfCpus field
> -                       in the System Management System Table (SMST).
> -  @param[in] RegName   Identifies the SMM register to check for support.
> -
> -  @retval TRUE   The SMM register specified by RegName is supported by
> the CPU
> -                 specified by CpuIndex.
> -  @retval FALSE  The SMM register specified by RegName is not supported
> by the
> -                 CPU specified by CpuIndex.
> -**/
> -BOOLEAN
> -EFIAPI
> -SmmCpuFeaturesIsSmmRegisterSupported (
> -  IN UINTN         CpuIndex,
> -  IN SMM_REG_NAME  RegName
> -  )
> -{
> -  if (FeaturePcdGet (PcdSmmFeatureControlEnable) && (RegName ==
> SmmRegFeatureControl)) {
> -    return TRUE;
> -  }
> -
> -  return FALSE;
> -}
> -
>  /**
>    Returns the current value of the SMM register for the specified CPU.
>    If the SMM register is not supported, then 0 is returned.
> @@ -506,100 +401,3 @@ SmmCpuFeaturesSetSmmRegister (
>    }
>  }
> 
> -/**
> -  Read an SMM Save State register on the target processor.  If this function
> -  returns EFI_UNSUPPORTED, then the caller is responsible for reading the
> -  SMM Save Sate register.
> -
> -  @param[in]  CpuIndex  The index of the CPU to read the SMM Save State.
> The
> -                        value must be between 0 and the NumberOfCpus field in
> -                        the System Management System Table (SMST).
> -  @param[in]  Register  The SMM Save State register to read.
> -  @param[in]  Width     The number of bytes to read from the CPU save state.
> -  @param[out] Buffer    Upon return, this holds the CPU register value read
> -                        from the save state.
> -
> -  @retval EFI_SUCCESS           The register was read from Save State.
> -  @retval EFI_INVALID_PARAMETER  Buffer is NULL.
> -  @retval EFI_UNSUPPORTED       This function does not support reading
> Register.
> -
> -**/
> -EFI_STATUS
> -EFIAPI
> -SmmCpuFeaturesReadSaveStateRegister (
> -  IN  UINTN                        CpuIndex,
> -  IN  EFI_SMM_SAVE_STATE_REGISTER  Register,
> -  IN  UINTN                        Width,
> -  OUT VOID                         *Buffer
> -  )
> -{
> -  return EFI_UNSUPPORTED;
> -}
> -
> -/**
> -  Writes an SMM Save State register on the target processor.  If this function
> -  returns EFI_UNSUPPORTED, then the caller is responsible for writing the
> -  SMM Save Sate register.
> -
> -  @param[in] CpuIndex  The index of the CPU to write the SMM Save State.
> The
> -                       value must be between 0 and the NumberOfCpus field in
> -                       the System Management System Table (SMST).
> -  @param[in] Register  The SMM Save State register to write.
> -  @param[in] Width     The number of bytes to write to the CPU save state.
> -  @param[in] Buffer    Upon entry, this holds the new CPU register value.
> -
> -  @retval EFI_SUCCESS           The register was written to Save State.
> -  @retval EFI_INVALID_PARAMETER  Buffer is NULL.
> -  @retval EFI_UNSUPPORTED       This function does not support writing
> Register.
> -**/
> -EFI_STATUS
> -EFIAPI
> -SmmCpuFeaturesWriteSaveStateRegister (
> -  IN UINTN                        CpuIndex,
> -  IN EFI_SMM_SAVE_STATE_REGISTER  Register,
> -  IN UINTN                        Width,
> -  IN CONST VOID                   *Buffer
> -  )
> -{
> -  return EFI_UNSUPPORTED;
> -}
> -
> -/**
> -  This function is hook point called after the
> gEfiSmmReadyToLockProtocolGuid
> -  notification is completely processed.
> -**/
> -VOID
> -EFIAPI
> -SmmCpuFeaturesCompleteSmmReadyToLock (
> -  VOID
> -  )
> -{
> -}
> -
> -/**
> -  This API provides a method for a CPU to allocate a specific region for storing
> page tables.
> -
> -  This API can be called more once to allocate memory for page tables.
> -
> -  Allocates the number of 4KB pages of type EfiRuntimeServicesData and
> returns a pointer to the
> -  allocated buffer.  The buffer returned is aligned on a 4KB boundary.  If
> Pages is 0, then NULL
> -  is returned.  If there is not enough memory remaining to satisfy the
> request, then NULL is
> -  returned.
> -
> -  This function can also return NULL if there is no preference on where the
> page tables are allocated in SMRAM.
> -
> -  @param  Pages                 The number of 4 KB pages to allocate.
> -
> -  @return A pointer to the allocated buffer for page tables.
> -  @retval NULL      Fail to allocate a specific region for storing page tables,
> -                    Or there is no preference on where the page tables are allocated
> in SMRAM.
> -
> -**/
> -VOID *
> -EFIAPI
> -SmmCpuFeaturesAllocatePageTableMemory (
> -  IN UINTN  Pages
> -  )
> -{
> -  return NULL;
> -}
> diff --git
> a/UefiCpuPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLibCommon.c
> b/UefiCpuPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLibCommon.c
> new file mode 100644
> index 00000000000..7777e52740e
> --- /dev/null
> +++
> b/UefiCpuPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLibCommon.c
> @@ -0,0 +1,216 @@
> +/** @file
> +Implementation shared across all library instances.
> +
> +Copyright (c) 2010 - 2019, Intel Corporation. All rights reserved.<BR>
> +Copyright (c) Microsoft Corporation.<BR>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <PiMm.h>
> +#include <Library/SmmCpuFeaturesLib.h>
> +#include <Library/BaseLib.h>
> +#include <Library/MtrrLib.h>
> +#include <Library/PcdLib.h>
> +#include <Library/MemoryAllocationLib.h>
> +#include <Library/DebugLib.h>
> +
> +#include "CpuFeaturesLib.h"
> +
> +/**
> +  This function updates the SMRAM save state on the currently executing
> CPU
> +  to resume execution at a specific address after an RSM instruction.  This
> +  function must evaluate the SMRAM save state to determine the execution
> mode
> +  the RSM instruction resumes and update the resume execution address
> with
> +  either NewInstructionPointer32 or NewInstructionPoint.  The auto HALT
> restart
> +  flag in the SMRAM save state must always be cleared.  This function
> returns
> +  the value of the instruction pointer from the SMRAM save state that was
> +  replaced.  If this function returns 0, then the SMRAM save state was not
> +  modified.
> +
> +  This function is called during the very first SMI on each CPU after
> +  SmmCpuFeaturesInitializeProcessor() to set a flag in normal execution
> mode
> +  to signal that the SMBASE of each CPU has been updated before the
> default
> +  SMBASE address is used for the first SMI to the next CPU.
> +
> +  @param[in] CpuIndex                 The index of the CPU to hook.  The value
> +                                      must be between 0 and the NumberOfCpus
> +                                      field in the System Management System Table
> +                                      (SMST).
> +  @param[in] CpuState                 Pointer to SMRAM Save State Map for the
> +                                      currently executing CPU.
> +  @param[in] NewInstructionPointer32  Instruction pointer to use if
> resuming to
> +                                      32-bit execution mode from 64-bit SMM.
> +  @param[in] NewInstructionPointer    Instruction pointer to use if resuming
> to
> +                                      same execution mode as SMM.
> +
> +  @retval 0    This function did modify the SMRAM save state.
> +  @retval > 0  The original instruction pointer value from the SMRAM save
> state
> +               before it was replaced.
> +**/
> +UINT64
> +EFIAPI
> +SmmCpuFeaturesHookReturnFromSmm (
> +  IN UINTN                 CpuIndex,
> +  IN SMRAM_SAVE_STATE_MAP  *CpuState,
> +  IN UINT64                NewInstructionPointer32,
> +  IN UINT64                NewInstructionPointer
> +  )
> +{
> +  return 0;
> +}
> +
> +/**
> +  Hook point in normal execution mode that allows the one CPU that was
> elected
> +  as monarch during System Management Mode initialization to perform
> additional
> +  initialization actions immediately after all of the CPUs have processed their
> +  first SMI and called SmmCpuFeaturesInitializeProcessor() relocating
> SMBASE
> +  into a buffer in SMRAM and called
> SmmCpuFeaturesHookReturnFromSmm().
> +**/
> +VOID
> +EFIAPI
> +SmmCpuFeaturesSmmRelocationComplete (
> +  VOID
> +  )
> +{
> +}
> +
> +/**
> +  Processor specific hook point each time a CPU exits System Management
> Mode.
> +
> +  @param[in] CpuIndex  The index of the CPU that is exiting SMM.  The
> value must
> +                       be between 0 and the NumberOfCpus field in the System
> +                       Management System Table (SMST).
> +**/
> +VOID
> +EFIAPI
> +SmmCpuFeaturesRendezvousExit (
> +  IN UINTN  CpuIndex
> +  )
> +{
> +}
> +
> +/**
> +  Check to see if an SMM register is supported by a specified CPU.
> +
> +  @param[in] CpuIndex  The index of the CPU to check for SMM register
> support.
> +                       The value must be between 0 and the NumberOfCpus field
> +                       in the System Management System Table (SMST).
> +  @param[in] RegName   Identifies the SMM register to check for support.
> +
> +  @retval TRUE   The SMM register specified by RegName is supported by
> the CPU
> +                 specified by CpuIndex.
> +  @retval FALSE  The SMM register specified by RegName is not supported
> by the
> +                 CPU specified by CpuIndex.
> +**/
> +BOOLEAN
> +EFIAPI
> +SmmCpuFeaturesIsSmmRegisterSupported (
> +  IN UINTN         CpuIndex,
> +  IN SMM_REG_NAME  RegName
> +  )
> +{
> +  if (FeaturePcdGet (PcdSmmFeatureControlEnable) && (RegName ==
> SmmRegFeatureControl)) {
> +    return TRUE;
> +  }
> +
> +  return FALSE;
> +}
> +
> +/**
> +  Read an SMM Save State register on the target processor.  If this function
> +  returns EFI_UNSUPPORTED, then the caller is responsible for reading the
> +  SMM Save Sate register.
> +
> +  @param[in]  CpuIndex  The index of the CPU to read the SMM Save State.
> The
> +                        value must be between 0 and the NumberOfCpus field in
> +                        the System Management System Table (SMST).
> +  @param[in]  Register  The SMM Save State register to read.
> +  @param[in]  Width     The number of bytes to read from the CPU save
> state.
> +  @param[out] Buffer    Upon return, this holds the CPU register value read
> +                        from the save state.
> +
> +  @retval EFI_SUCCESS           The register was read from Save State.
> +  @retval EFI_INVALID_PARAMETER  Buffer is NULL.
> +  @retval EFI_UNSUPPORTED       This function does not support reading
> Register.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +SmmCpuFeaturesReadSaveStateRegister (
> +  IN  UINTN                        CpuIndex,
> +  IN  EFI_SMM_SAVE_STATE_REGISTER  Register,
> +  IN  UINTN                        Width,
> +  OUT VOID                         *Buffer
> +  )
> +{
> +  return EFI_UNSUPPORTED;
> +}
> +
> +/**
> +  Writes an SMM Save State register on the target processor.  If this function
> +  returns EFI_UNSUPPORTED, then the caller is responsible for writing the
> +  SMM Save Sate register.
> +
> +  @param[in] CpuIndex  The index of the CPU to write the SMM Save State.
> The
> +                       value must be between 0 and the NumberOfCpus field in
> +                       the System Management System Table (SMST).
> +  @param[in] Register  The SMM Save State register to write.
> +  @param[in] Width     The number of bytes to write to the CPU save state.
> +  @param[in] Buffer    Upon entry, this holds the new CPU register value.
> +
> +  @retval EFI_SUCCESS           The register was written to Save State.
> +  @retval EFI_INVALID_PARAMETER  Buffer is NULL.
> +  @retval EFI_UNSUPPORTED       This function does not support writing
> Register.
> +**/
> +EFI_STATUS
> +EFIAPI
> +SmmCpuFeaturesWriteSaveStateRegister (
> +  IN UINTN                        CpuIndex,
> +  IN EFI_SMM_SAVE_STATE_REGISTER  Register,
> +  IN UINTN                        Width,
> +  IN CONST VOID                   *Buffer
> +  )
> +{
> +  return EFI_UNSUPPORTED;
> +}
> +
> +/**
> +  This function is hook point called after the
> gEfiSmmReadyToLockProtocolGuid
> +  notification is completely processed.
> +**/
> +VOID
> +EFIAPI
> +SmmCpuFeaturesCompleteSmmReadyToLock (
> +  VOID
> +  )
> +{
> +}
> +
> +/**
> +  This API provides a method for a CPU to allocate a specific region for
> storing page tables.
> +
> +  This API can be called more once to allocate memory for page tables.
> +
> +  Allocates the number of 4KB pages of type EfiRuntimeServicesData and
> returns a pointer to the
> +  allocated buffer.  The buffer returned is aligned on a 4KB boundary.  If
> Pages is 0, then NULL
> +  is returned.  If there is not enough memory remaining to satisfy the
> request, then NULL is
> +  returned.
> +
> +  This function can also return NULL if there is no preference on where the
> page tables are allocated in SMRAM.
> +
> +  @param  Pages                 The number of 4 KB pages to allocate.
> +
> +  @return A pointer to the allocated buffer for page tables.
> +  @retval NULL      Fail to allocate a specific region for storing page tables,
> +                    Or there is no preference on where the page tables are allocated
> in SMRAM.
> +
> +**/
> +VOID *
> +EFIAPI
> +SmmCpuFeaturesAllocatePageTableMemory (
> +  IN UINTN  Pages
> +  )
> +{
> +  return NULL;
> +}
> --
> 2.37.1.windows.1