49 lines
1.3 KiB
C
49 lines
1.3 KiB
C
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/** @file
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Define the module hooks used while probing the QEMU flash device.
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Copyright (C) 2018, Advanced Micro Devices. All rights reserved.
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include <Library/BaseMemoryLib.h>
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#include <Library/DebugLib.h>
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#include <Library/PcdLib.h>
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#include <Library/MemEncryptSevLib.h>
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#include "QemuFlash.h"
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VOID
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QemuFlashBeforeProbe (
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IN EFI_PHYSICAL_ADDRESS BaseAddress,
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IN UINTN FdBlockSize,
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IN UINTN FdBlockCount
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)
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{
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EFI_STATUS Status;
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ASSERT (FeaturePcdGet (PcdSmmSmramRequire));
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if (!MemEncryptSevIsEnabled ()) {
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return;
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}
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//
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// When SEV is enabled, AmdSevDxe runs early in DXE phase and clears the
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// C-bit from the NonExistent entry -- which is later split and accommodate
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// the flash MMIO but the driver runs in non SMM context hence it cleared the
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// flash ranges from non SMM page table. When SMM is enabled, the flash
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// services are accessed from the SMM mode hence we explicitly clear the
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// C-bit on flash ranges from SMM page table.
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//
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Status = MemEncryptSevClearPageEncMask (
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0,
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BaseAddress,
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EFI_SIZE_TO_PAGES (FdBlockSize * FdBlockCount),
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FALSE
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);
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ASSERT_EFI_ERROR (Status);
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}
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