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/** @file
Secure Encrypted Virtualization (SEV) library helper function
Copyright (c) 2017 - 2020, AMD Incorporated. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/MemEncryptSevLib.h>
#include <Library/PcdLib.h>
#include <Register/Amd/SmramSaveStateMap.h>
#include <Register/SmramSaveStateMap.h>
#include <Uefi/UefiBaseType.h>
/**
Locate the page range that covers the initial (pre-SMBASE-relocation) SMRAM
Save State Map.
@param[out] BaseAddress The base address of the lowest-address page that
covers the initial SMRAM Save State Map.
@param[out] NumberOfPages The number of pages in the page range that covers
the initial SMRAM Save State Map.
@retval RETURN_SUCCESS BaseAddress and NumberOfPages have been set on
output.
@retval RETURN_UNSUPPORTED SMM is unavailable.
**/
RETURN_STATUS
EFIAPI
MemEncryptSevLocateInitialSmramSaveStateMapPages (
OUT UINTN *BaseAddress,
OUT UINTN *NumberOfPages
)
{
UINTN MapStart;
UINTN MapEnd;
UINTN MapPagesStart; // MapStart rounded down to page boundary
UINTN MapPagesEnd; // MapEnd rounded up to page boundary
UINTN MapPagesSize; // difference between MapPagesStart and MapPagesEnd
if (!FeaturePcdGet (PcdSmmSmramRequire)) {
return RETURN_UNSUPPORTED;
}
MapStart = SMM_DEFAULT_SMBASE + SMRAM_SAVE_STATE_MAP_OFFSET;
MapEnd = MapStart + sizeof (AMD_SMRAM_SAVE_STATE_MAP);
MapPagesStart = MapStart & ~(UINTN)EFI_PAGE_MASK;
MapPagesEnd = ALIGN_VALUE (MapEnd, EFI_PAGE_SIZE);
MapPagesSize = MapPagesEnd - MapPagesStart;
ASSERT ((MapPagesSize & EFI_PAGE_MASK) == 0);
*BaseAddress = MapPagesStart;
*NumberOfPages = MapPagesSize >> EFI_PAGE_SHIFT;
return RETURN_SUCCESS;
}
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