/** @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; | |
} |