SmmAccessPei.c File Reference

#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/IoLib.h>
#include <Library/PcdLib.h>
#include <Library/PciLib.h>
#include <Library/PeiServicesLib.h>
#include <Ppi/SmmAccess.h>
#include <OvmfPlatforms.h>
#include "SmramInternal.h"

Go to the source code of this file.

Functions
STATIC EFI_STATUS EFIAPI	SmmAccessPeiOpen (IN EFI_PEI_SERVICES **PeiServices, IN PEI_SMM_ACCESS_PPI *This, IN UINTN DescriptorIndex)
STATIC EFI_STATUS EFIAPI	SmmAccessPeiClose (IN EFI_PEI_SERVICES **PeiServices, IN PEI_SMM_ACCESS_PPI *This, IN UINTN DescriptorIndex)
STATIC EFI_STATUS EFIAPI	SmmAccessPeiLock (IN EFI_PEI_SERVICES **PeiServices, IN PEI_SMM_ACCESS_PPI *This, IN UINTN DescriptorIndex)
STATIC EFI_STATUS EFIAPI	SmmAccessPeiGetCapabilities (IN EFI_PEI_SERVICES **PeiServices, IN PEI_SMM_ACCESS_PPI *This, IN OUT UINTN *SmramMapSize, IN OUT EFI_SMRAM_DESCRIPTOR *SmramMap)
STATIC UINT8	CmosRead8 (IN UINT8 Index)
STATIC UINT32	GetSystemMemorySizeBelow4gb (VOID)
EFI_STATUS EFIAPI	SmmAccessPeiEntryPoint (IN EFI_PEI_FILE_HANDLE FileHandle, IN CONST EFI_PEI_SERVICES **PeiServices)

Variables
STATIC PEI_SMM_ACCESS_PPI	mAccess
STATIC EFI_PEI_PPI_DESCRIPTOR	mPpiList []

Detailed Description

A PEIM with the following responsibilities:

• verify & configure the Q35 TSEG in the entry point,
• provide SMRAM access by producing PEI_SMM_ACCESS_PPI

This PEIM runs from RAM, so we can write to variables with static storage duration.

Copyright (C) 2013, 2015, Red Hat, Inc.
Copyright (c) 2010 - 2024, Intel Corporation. All rights reserved.

SPDX-License-Identifier: BSD-2-Clause-Patent

Definition in file SmmAccessPei.c.

Function Documentation

CmosRead8()

STATIC UINT8 CmosRead8

(

IN UINT8

Index

)

Definition at line 234 of file SmmAccessPei.c.

GetSystemMemorySizeBelow4gb()

STATIC UINT32 GetSystemMemorySizeBelow4gb

(

VOID

)

Definition at line 244 of file SmmAccessPei.c.

SmmAccessPeiClose()

STATIC EFI_STATUS EFIAPI SmmAccessPeiClose	(	IN EFI_PEI_SERVICES **	PeiServices,
		IN PEI_SMM_ACCESS_PPI *	This,
		IN UINTN	DescriptorIndex
	)

Inhibits access to the SMRAM.

This function "closes" SMRAM so that it is not visible while outside of SMM. The function should return EFI_UNSUPPORTED if the hardware does not support hiding of SMRAM.

Parameters

PeiServices	General purpose services available to every PEIM.
This	The pointer to the SMM Access Interface.
DescriptorIndex	The region of SMRAM to Close.

Return values

EFI_SUCCESS	The region was successfully closed.
EFI_DEVICE_ERROR	The region could not be closed because locked by chipset.
EFI_INVALID_PARAMETER	The descriptor index was out of bounds.

Definition at line 105 of file SmmAccessPei.c.

SmmAccessPeiEntryPoint()

EFI_STATUS EFIAPI SmmAccessPeiEntryPoint	(	IN EFI_PEI_FILE_HANDLE	FileHandle,
		IN CONST EFI_PEI_SERVICES **	PeiServices
	)

Definition at line 262 of file SmmAccessPei.c.

SmmAccessPeiGetCapabilities()

STATIC EFI_STATUS EFIAPI SmmAccessPeiGetCapabilities	(	IN EFI_PEI_SERVICES **	PeiServices,
		IN PEI_SMM_ACCESS_PPI *	This,
		IN OUT UINTN *	SmramMapSize,
		IN OUT EFI_SMRAM_DESCRIPTOR *	SmramMap
	)

Queries the memory controller for the possible regions that will support SMRAM.

Parameters

PeiServices	General purpose services available to every PEIM.
This	The pointer to the SmmAccessPpi Interface.
SmramMapSize	The pointer to the variable containing size of the buffer to contain the description information.
SmramMap	The buffer containing the data describing the Smram region descriptors.

Return values

EFI_BUFFER_TOO_SMALL	The user did not provide a sufficient buffer.
EFI_SUCCESS	The user provided a sufficiently-sized buffer.

Definition at line 199 of file SmmAccessPei.c.

SmmAccessPeiLock()

STATIC EFI_STATUS EFIAPI SmmAccessPeiLock	(	IN EFI_PEI_SERVICES **	PeiServices,
		IN PEI_SMM_ACCESS_PPI *	This,
		IN UINTN	DescriptorIndex
	)

Inhibits access to the SMRAM.

This function prohibits access to the SMRAM region. This function is usually implemented such that it is a write-once operation.

Parameters

PeiServices	General purpose services available to every PEIM.
This	The pointer to the SMM Access Interface.
DescriptorIndex	The region of SMRAM to Close.

Return values

EFI_SUCCESS	The region was successfully locked.
EFI_DEVICE_ERROR	The region could not be locked because at least one range is still open.
EFI_INVALID_PARAMETER	The descriptor index was out of bounds.

Definition at line 152 of file SmmAccessPei.c.

SmmAccessPeiOpen()

STATIC EFI_STATUS EFIAPI SmmAccessPeiOpen	(	IN EFI_PEI_SERVICES **	PeiServices,
		IN PEI_SMM_ACCESS_PPI *	This,
		IN UINTN	DescriptorIndex
	)

Opens the SMRAM area to be accessible by a PEIM driver.

This function "opens" SMRAM so that it is visible while not inside of SMM. The function should return EFI_UNSUPPORTED if the hardware does not support hiding of SMRAM. The function should return EFI_DEVICE_ERROR if the SMRAM configuration is locked.

Parameters

PeiServices	General purpose services available to every PEIM.
This	The pointer to the SMM Access Interface.
DescriptorIndex	The region of SMRAM to Open.

Return values

EFI_SUCCESS	The region was successfully opened.
EFI_DEVICE_ERROR	The region could not be opened because locked by chipset.
EFI_INVALID_PARAMETER	The descriptor index was out of bounds.

Definition at line 57 of file SmmAccessPei.c.

Variable Documentation

mAccess

STATIC PEI_SMM_ACCESS_PPI mAccess

Initial value:

= {
  &SmmAccessPeiOpen,
  &SmmAccessPeiClose,
  &SmmAccessPeiLock,
  &SmmAccessPeiGetCapabilities
}

Definition at line 215 of file SmmAccessPei.c.

mPpiList

STATIC EFI_PEI_PPI_DESCRIPTOR mPpiList[]

Initial value:

= {
  {
    EFI_PEI_PPI_DESCRIPTOR_PPI | EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST,
    &gPeiSmmAccessPpiGuid, &mAccess
  }
}

Definition at line 222 of file SmmAccessPei.c.