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c5d5b3e796
This is a small refactor to the BaseMemEncryptSevLib in the OvmfPkg which moves the function used in the Pei phase for accessing the SEC_SEV_ES_WORK_AREA, into the common Pei and Dxe code. The Dxe phase will consume the work area in a subsequent patch. Signed-off-by: John Berg <jhnberg@amazon.co.uk>
89 lines
2.5 KiB
C
89 lines
2.5 KiB
C
/** @file
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Secure Encrypted Virtualization (SEV) library helper function
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Copyright (c) 2017 - 2020, AMD Incorporated. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include <Library/BaseLib.h>
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#include <Library/DebugLib.h>
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#include <Library/MemEncryptSevLib.h>
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#include <Library/PcdLib.h>
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#include <Register/Amd/SmramSaveStateMap.h>
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#include <Register/SmramSaveStateMap.h>
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#include <Uefi/UefiBaseType.h>
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#include "PeiDxeMemEncryptSevLibInternal.h"
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/**
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Read the workarea to determine whether SEV is enabled. If enabled,
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then return the SevEsWorkArea pointer.
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**/
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SEC_SEV_ES_WORK_AREA *
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EFIAPI
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GetSevEsWorkArea (
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VOID
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)
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{
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OVMF_WORK_AREA *WorkArea;
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WorkArea = (OVMF_WORK_AREA *)FixedPcdGet32 (PcdOvmfWorkAreaBase);
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//
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// If its not SEV guest then SevEsWorkArea is not valid.
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//
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if ((WorkArea == NULL) || (WorkArea->Header.GuestType != CcGuestTypeAmdSev)) {
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return NULL;
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}
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return (SEC_SEV_ES_WORK_AREA *)FixedPcdGet32 (PcdSevEsWorkAreaBase);
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}
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/**
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Locate the page range that covers the initial (pre-SMBASE-relocation) SMRAM
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Save State Map.
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@param[out] BaseAddress The base address of the lowest-address page that
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covers the initial SMRAM Save State Map.
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@param[out] NumberOfPages The number of pages in the page range that covers
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the initial SMRAM Save State Map.
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@retval RETURN_SUCCESS BaseAddress and NumberOfPages have been set on
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output.
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@retval RETURN_UNSUPPORTED SMM is unavailable.
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**/
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RETURN_STATUS
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EFIAPI
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MemEncryptSevLocateInitialSmramSaveStateMapPages (
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OUT UINTN *BaseAddress,
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OUT UINTN *NumberOfPages
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)
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{
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UINTN MapStart;
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UINTN MapEnd;
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UINTN MapPagesStart; // MapStart rounded down to page boundary
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UINTN MapPagesEnd; // MapEnd rounded up to page boundary
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UINTN MapPagesSize; // difference between MapPagesStart and MapPagesEnd
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if (!FeaturePcdGet (PcdSmmSmramRequire)) {
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return RETURN_UNSUPPORTED;
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}
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MapStart = SMM_DEFAULT_SMBASE + SMRAM_SAVE_STATE_MAP_OFFSET;
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MapEnd = MapStart + sizeof (AMD_SMRAM_SAVE_STATE_MAP);
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MapPagesStart = MapStart & ~(UINTN)EFI_PAGE_MASK;
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MapPagesEnd = ALIGN_VALUE (MapEnd, EFI_PAGE_SIZE);
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MapPagesSize = MapPagesEnd - MapPagesStart;
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ASSERT ((MapPagesSize & EFI_PAGE_MASK) == 0);
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*BaseAddress = MapPagesStart;
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*NumberOfPages = MapPagesSize >> EFI_PAGE_SHIFT;
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return RETURN_SUCCESS;
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}
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