/** @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/QemuSmramSaveStateMap.h>
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#include <Register/SmramSaveStateMap.h>
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#include <Uefi/UefiBaseType.h>
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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 (QEMU_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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