UefiCpuPkg/Include/Library/SmmCpuFeaturesLib.h - third_party/edk2 - Git at Google

 /** @file
 Library that provides CPU specific functions to support the PiSmmCpuDxeSmm module.

 Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
 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.

 **/

 #ifndef __SMM_FEATURES_LIB_H__
 #define __SMM_FEATURES_LIB_H__

 #include <Protocol/MpService.h>
 #include <Protocol/SmmCpu.h>
 #include <Register/SmramSaveStateMap.h>
 #include <CpuHotPlugData.h>

 ///
 /// Enumeration of SMM registers that are accessed using the library functions
 /// SmmCpuFeaturesIsSmmRegisterSupported (), SmmCpuFeaturesGetSmmRegister (),
 /// and SmmCpuFeaturesSetSmmRegister ().
 ///
 typedef enum {
   ///
   /// Read-write register to provides access to MSR_SMM_FEATURE_CONTROL if the
   /// CPU supports this MSR.
   ///
   SmmRegFeatureControl,
   ///
   /// Read-only register that returns a non-zero value if the CPU is able to
   /// respond to SMIs.
   ///
   SmmRegSmmEnable,
   ///
   /// Read-only register that returns a non-zero value if the CPU is able to
   /// respond to SMIs, but is busy with other actions that are causing a delay
   /// in responding to an SMI.  This register abstracts access to MSR_SMM_DELAYED
   /// if the CPU supports this MSR.
   ///
   SmmRegSmmDelayed,
   ///
   /// Read-only register that returns a non-zero value if the CPU is able to
   /// respond to SMIs, but is busy with other actions that are blocking its
   /// ability to respond to an SMI.  This register abstracts access to
   /// MSR_SMM_BLOCKED if the CPU supports this MSR.
   ///
   SmmRegSmmBlocked
 } SMM_REG_NAME;

 /**
   Called during the very first SMI into System Management Mode to initialize
   CPU features, including SMBASE, for the currently executing CPU.  Since this
   is the first SMI, the SMRAM Save State Map is at the default address of
   SMM_DEFAULT_SMBASE + SMRAM_SAVE_STATE_MAP_OFFSET.  The currently executing
   CPU is specified by CpuIndex and CpuIndex can be used to access information
   about the currently executing CPU in the ProcessorInfo array and the
   HotPlugCpuData data structure.

   @param[in] CpuIndex        The index of the CPU to initialize.  The value
                              must be between 0 and the NumberOfCpus field in
                              the System Management System Table (SMST).
   @param[in] IsMonarch       TRUE if the CpuIndex is the index of the CPU that
                              was elected as monarch during System Management
                              Mode initialization.
                              FALSE if the CpuIndex is not the index of the CPU
                              that was elected as monarch during System
                              Management Mode initialization.
   @param[in] ProcessorInfo   Pointer to an array of EFI_PROCESSOR_INFORMATION
                              structures.  ProcessorInfo[CpuIndex] contains the
                              information for the currently executing CPU.
   @param[in] CpuHotPlugData  Pointer to the CPU_HOT_PLUG_DATA structure that
                              contains the ApidId and SmBase arrays.
 **/
 VOID
 EFIAPI
 SmmCpuFeaturesInitializeProcessor (
   IN UINTN                      CpuIndex,
   IN BOOLEAN                    IsMonarch,
   IN EFI_PROCESSOR_INFORMATION  *ProcessorInfo,
   IN CPU_HOT_PLUG_DATA          *CpuHotPlugData
   );

 /**
   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
   );

 /**
   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
   );

 /**
   Return the size, in bytes, of a custom SMI Handler in bytes.  If 0 is
   returned, then a custom SMI handler is not provided by this library,
   and the default SMI handler must be used.

   @retval 0    Use the default SMI handler.
   @retval > 0  Use the SMI handler installed by SmmCpuFeaturesInstallSmiHandler()
                The caller is required to allocate enough SMRAM for each CPU to
                support the size of the custom SMI handler.
 **/
 UINTN
 EFIAPI
 SmmCpuFeaturesGetSmiHandlerSize (
   VOID
   );

 /**
   Install a custom SMI handler for the CPU specified by CpuIndex.  This function
   is only called if SmmCpuFeaturesGetSmiHandlerSize() returns a size is greater
   than zero and is called by the CPU that was elected as monarch during System
   Management Mode initialization.

   @param[in] CpuIndex   The index of the CPU to install the custom SMI handler.
                         The value must be between 0 and the NumberOfCpus field
                         in the System Management System Table (SMST).
   @param[in] SmBase     The SMBASE address for the CPU specified by CpuIndex.
   @param[in] SmiStack   The stack to use when an SMI is processed by the
                         the CPU specified by CpuIndex.
   @param[in] StackSize  The size, in bytes, if the stack used when an SMI is
                         processed by the CPU specified by CpuIndex.
   @param[in] GdtBase    The base address of the GDT to use when an SMI is
                         processed by the CPU specified by CpuIndex.
   @param[in] GdtSize    The size, in bytes, of the GDT used when an SMI is
                         processed by the CPU specified by CpuIndex.
   @param[in] IdtBase    The base address of the IDT to use when an SMI is
                         processed by the CPU specified by CpuIndex.
   @param[in] IdtSize    The size, in bytes, of the IDT used when an SMI is
                         processed by the CPU specified by CpuIndex.
   @param[in] Cr3        The base address of the page tables to use when an SMI
                         is processed by the CPU specified by CpuIndex.
 **/
 VOID
 EFIAPI
 SmmCpuFeaturesInstallSmiHandler (
   IN UINTN   CpuIndex,
   IN UINT32  SmBase,
   IN VOID    *SmiStack,
   IN UINTN   StackSize,
   IN UINTN   GdtBase,
   IN UINTN   GdtSize,
   IN UINTN   IdtBase,
   IN UINTN   IdtSize,
   IN UINT32  Cr3
   );

 /**
   Determines if MTRR registers must be configured to set SMRAM cache-ability
   when executing in System Management Mode.

   @retval TRUE   MTRR registers must be configured to set SMRAM cache-ability.
   @retval FALSE  MTRR registers do not need to be configured to set SMRAM
                  cache-ability.
 **/
 BOOLEAN
 EFIAPI
 SmmCpuFeaturesNeedConfigureMtrrs (
   VOID
   );

 /**
   Disable SMRR register if SMRR is supported and SmmCpuFeaturesNeedConfigureMtrrs()
   returns TRUE.
 **/
 VOID
 EFIAPI
 SmmCpuFeaturesDisableSmrr (
   VOID
   );

 /**
   Enable SMRR register if SMRR is supported and SmmCpuFeaturesNeedConfigureMtrrs()
   returns TRUE.
 **/
 VOID
 EFIAPI
 SmmCpuFeaturesReenableSmrr (
   VOID
   );

 /**
   Processor specific hook point each time a CPU enters System Management Mode.

   @param[in] CpuIndex  The index of the CPU that has entered SMM.  The value
                        must be between 0 and the NumberOfCpus field in the
                        System Management System Table (SMST).
 **/
 VOID
 EFIAPI
 SmmCpuFeaturesRendezvousEntry (
   IN UINTN  CpuIndex
   );

 /**
   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
   );

 /**
   Returns the current value of the SMM register for the specified CPU.
   If the SMM register is not supported, then 0 is returned.

   @param[in] CpuIndex  The index of the CPU to read the SMM register.  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 read.

   @return  The value of the SMM register specified by RegName from the CPU
            specified by CpuIndex.
 **/
 UINT64
 EFIAPI
 SmmCpuFeaturesGetSmmRegister (
   IN UINTN         CpuIndex,
   IN SMM_REG_NAME  RegName
   );

 /**
   Sets the value of an SMM register on a specified CPU.
   If the SMM register is not supported, then no action is performed.

   @param[in] CpuIndex  The index of the CPU to write the SMM register.  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 write.
                        registers are read-only.
   @param[in] Value     The value to write to the SMM register.
 **/
 VOID
 EFIAPI
 SmmCpuFeaturesSetSmmRegister (
   IN UINTN         CpuIndex,
   IN SMM_REG_NAME  RegName,
   IN UINT64        Value
   );

 /**
   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_PARAMTER  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
   );

 /**
   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_PARAMTER  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
   );

 /**
   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
   );

 #endif
	/** @file
	Library that provides CPU specific functions to support the PiSmmCpuDxeSmm module.

	Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
	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.

	**/

	#ifndef __SMM_FEATURES_LIB_H__
	#define __SMM_FEATURES_LIB_H__

	#include <Protocol/MpService.h>
	#include <Protocol/SmmCpu.h>
	#include <Register/SmramSaveStateMap.h>
	#include <CpuHotPlugData.h>

	///
	/// Enumeration of SMM registers that are accessed using the library functions
	/// SmmCpuFeaturesIsSmmRegisterSupported (), SmmCpuFeaturesGetSmmRegister (),
	/// and SmmCpuFeaturesSetSmmRegister ().
	///
	typedef enum {
	///
	/// Read-write register to provides access to MSR_SMM_FEATURE_CONTROL if the
	/// CPU supports this MSR.
	///
	SmmRegFeatureControl,
	///
	/// Read-only register that returns a non-zero value if the CPU is able to
	/// respond to SMIs.
	///
	SmmRegSmmEnable,
	///
	/// Read-only register that returns a non-zero value if the CPU is able to
	/// respond to SMIs, but is busy with other actions that are causing a delay
	/// in responding to an SMI. This register abstracts access to MSR_SMM_DELAYED
	/// if the CPU supports this MSR.
	///
	SmmRegSmmDelayed,
	///
	/// Read-only register that returns a non-zero value if the CPU is able to
	/// respond to SMIs, but is busy with other actions that are blocking its
	/// ability to respond to an SMI. This register abstracts access to
	/// MSR_SMM_BLOCKED if the CPU supports this MSR.
	///
	SmmRegSmmBlocked
	} SMM_REG_NAME;

	/**
	Called during the very first SMI into System Management Mode to initialize
	CPU features, including SMBASE, for the currently executing CPU. Since this
	is the first SMI, the SMRAM Save State Map is at the default address of
	SMM_DEFAULT_SMBASE + SMRAM_SAVE_STATE_MAP_OFFSET. The currently executing
	CPU is specified by CpuIndex and CpuIndex can be used to access information
	about the currently executing CPU in the ProcessorInfo array and the
	HotPlugCpuData data structure.

	@param[in] CpuIndex The index of the CPU to initialize. The value
	must be between 0 and the NumberOfCpus field in
	the System Management System Table (SMST).
	@param[in] IsMonarch TRUE if the CpuIndex is the index of the CPU that
	was elected as monarch during System Management
	Mode initialization.
	FALSE if the CpuIndex is not the index of the CPU
	that was elected as monarch during System
	Management Mode initialization.
	@param[in] ProcessorInfo Pointer to an array of EFI_PROCESSOR_INFORMATION
	structures. ProcessorInfo[CpuIndex] contains the
	information for the currently executing CPU.
	@param[in] CpuHotPlugData Pointer to the CPU_HOT_PLUG_DATA structure that
	contains the ApidId and SmBase arrays.
	**/
	VOID
	EFIAPI
	SmmCpuFeaturesInitializeProcessor (
	IN UINTN CpuIndex,
	IN BOOLEAN IsMonarch,
	IN EFI_PROCESSOR_INFORMATION *ProcessorInfo,
	IN CPU_HOT_PLUG_DATA *CpuHotPlugData
	);

	/**
	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
	);

	/**
	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
	);

	/**
	Return the size, in bytes, of a custom SMI Handler in bytes. If 0 is
	returned, then a custom SMI handler is not provided by this library,
	and the default SMI handler must be used.

	@retval 0 Use the default SMI handler.
	@retval > 0 Use the SMI handler installed by SmmCpuFeaturesInstallSmiHandler()
	The caller is required to allocate enough SMRAM for each CPU to
	support the size of the custom SMI handler.
	**/
	UINTN
	EFIAPI
	SmmCpuFeaturesGetSmiHandlerSize (
	VOID
	);

	/**
	Install a custom SMI handler for the CPU specified by CpuIndex. This function
	is only called if SmmCpuFeaturesGetSmiHandlerSize() returns a size is greater
	than zero and is called by the CPU that was elected as monarch during System
	Management Mode initialization.

	@param[in] CpuIndex The index of the CPU to install the custom SMI handler.
	The value must be between 0 and the NumberOfCpus field
	in the System Management System Table (SMST).
	@param[in] SmBase The SMBASE address for the CPU specified by CpuIndex.
	@param[in] SmiStack The stack to use when an SMI is processed by the
	the CPU specified by CpuIndex.
	@param[in] StackSize The size, in bytes, if the stack used when an SMI is
	processed by the CPU specified by CpuIndex.
	@param[in] GdtBase The base address of the GDT to use when an SMI is
	processed by the CPU specified by CpuIndex.
	@param[in] GdtSize The size, in bytes, of the GDT used when an SMI is
	processed by the CPU specified by CpuIndex.
	@param[in] IdtBase The base address of the IDT to use when an SMI is
	processed by the CPU specified by CpuIndex.
	@param[in] IdtSize The size, in bytes, of the IDT used when an SMI is
	processed by the CPU specified by CpuIndex.
	@param[in] Cr3 The base address of the page tables to use when an SMI
	is processed by the CPU specified by CpuIndex.
	**/
	VOID
	EFIAPI
	SmmCpuFeaturesInstallSmiHandler (
	IN UINTN CpuIndex,
	IN UINT32 SmBase,
	IN VOID *SmiStack,
	IN UINTN StackSize,
	IN UINTN GdtBase,
	IN UINTN GdtSize,
	IN UINTN IdtBase,
	IN UINTN IdtSize,
	IN UINT32 Cr3
	);

	/**
	Determines if MTRR registers must be configured to set SMRAM cache-ability
	when executing in System Management Mode.

	@retval TRUE MTRR registers must be configured to set SMRAM cache-ability.
	@retval FALSE MTRR registers do not need to be configured to set SMRAM
	cache-ability.
	**/
	BOOLEAN
	EFIAPI
	SmmCpuFeaturesNeedConfigureMtrrs (
	VOID
	);

	/**
	Disable SMRR register if SMRR is supported and SmmCpuFeaturesNeedConfigureMtrrs()
	returns TRUE.
	**/
	VOID
	EFIAPI
	SmmCpuFeaturesDisableSmrr (
	VOID
	);

	/**
	Enable SMRR register if SMRR is supported and SmmCpuFeaturesNeedConfigureMtrrs()
	returns TRUE.
	**/
	VOID
	EFIAPI
	SmmCpuFeaturesReenableSmrr (
	VOID
	);

	/**
	Processor specific hook point each time a CPU enters System Management Mode.

	@param[in] CpuIndex The index of the CPU that has entered SMM. The value
	must be between 0 and the NumberOfCpus field in the
	System Management System Table (SMST).
	**/
	VOID
	EFIAPI
	SmmCpuFeaturesRendezvousEntry (
	IN UINTN CpuIndex
	);

	/**
	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
	);

	/**
	Returns the current value of the SMM register for the specified CPU.
	If the SMM register is not supported, then 0 is returned.

	@param[in] CpuIndex The index of the CPU to read the SMM register. 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 read.

	@return The value of the SMM register specified by RegName from the CPU
	specified by CpuIndex.
	**/
	UINT64
	EFIAPI
	SmmCpuFeaturesGetSmmRegister (
	IN UINTN CpuIndex,
	IN SMM_REG_NAME RegName
	);

	/**
	Sets the value of an SMM register on a specified CPU.
	If the SMM register is not supported, then no action is performed.

	@param[in] CpuIndex The index of the CPU to write the SMM register. 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 write.
	registers are read-only.
	@param[in] Value The value to write to the SMM register.
	**/
	VOID
	EFIAPI
	SmmCpuFeaturesSetSmmRegister (
	IN UINTN CpuIndex,
	IN SMM_REG_NAME RegName,
	IN UINT64 Value
	);

	/**
	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_PARAMTER 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
	);

	/**
	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_PARAMTER 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
	);

	/**
	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
	);

	#endif