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/** @file
Define the module hooks used while probing the QEMU flash device.
Copyright (C) 2018, Advanced Micro Devices. All rights reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/PcdLib.h>
#include <Library/MemEncryptSevLib.h>
#include "QemuFlash.h"
VOID
QemuFlashBeforeProbe (
IN EFI_PHYSICAL_ADDRESS BaseAddress,
IN UINTN FdBlockSize,
IN UINTN FdBlockCount
)
{
EFI_STATUS Status;
ASSERT (FeaturePcdGet (PcdSmmSmramRequire));
if (!MemEncryptSevIsEnabled ()) {
return;
}
//
// When SEV is enabled, AmdSevDxe runs early in DXE phase and clears the
// C-bit from the NonExistent entry -- which is later split and accommodate
// the flash MMIO but the driver runs in non SMM context hence it cleared the
// flash ranges from non SMM page table. When SMM is enabled, the flash
// services are accessed from the SMM mode hence we explicitly clear the
// C-bit on flash ranges from SMM page table.
//
Status = MemEncryptSevClearMmioPageEncMask (
0,
BaseAddress,
EFI_SIZE_TO_PAGES (FdBlockSize * FdBlockCount)
);
ASSERT_EFI_ERROR (Status);
}
/**
Write to QEMU Flash
@param[in] Ptr Pointer to the location to write.
@param[in] Value The value to write.
**/
VOID
QemuFlashPtrWrite (
IN volatile UINT8 *Ptr,
IN UINT8 Value
)
{
*Ptr = Value;
}
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