audk/OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLibInternal.c

169 lines
3.5 KiB
C

/** @file
Secure Encrypted Virtualization (SEV) library helper function
Copyright (c) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/MemEncryptSevLib.h>
#include <Library/PcdLib.h>
#include <Register/Amd/Cpuid.h>
#include <Register/Amd/Msr.h>
#include <Register/Cpuid.h>
#include <Uefi/UefiBaseType.h>
/**
Read the workarea to determine whether SEV is enabled. If enabled,
then return the SevEsWorkArea pointer.
**/
STATIC
SEC_SEV_ES_WORK_AREA *
EFIAPI
GetSevEsWorkArea (
VOID
)
{
OVMF_WORK_AREA *WorkArea;
WorkArea = (OVMF_WORK_AREA *)FixedPcdGet32 (PcdOvmfWorkAreaBase);
//
// If its not SEV guest then SevEsWorkArea is not valid.
//
if ((WorkArea == NULL) || (WorkArea->Header.GuestType != CcGuestTypeAmdSev)) {
return NULL;
}
return (SEC_SEV_ES_WORK_AREA *)FixedPcdGet32 (PcdSevEsWorkAreaBase);
}
/**
Read the SEV Status MSR value from the workarea
**/
STATIC
UINT32
EFIAPI
InternalMemEncryptSevStatus (
VOID
)
{
SEC_SEV_ES_WORK_AREA *SevEsWorkArea;
SevEsWorkArea = GetSevEsWorkArea ();
if (SevEsWorkArea == NULL) {
return 0;
}
return (UINT32)(UINTN)SevEsWorkArea->SevStatusMsrValue;
}
/**
Returns a boolean to indicate whether SEV-SNP is enabled.
@retval TRUE SEV-SNP is enabled
@retval FALSE SEV-SNP is not enabled
**/
BOOLEAN
EFIAPI
MemEncryptSevSnpIsEnabled (
VOID
)
{
MSR_SEV_STATUS_REGISTER Msr;
Msr.Uint32 = InternalMemEncryptSevStatus ();
return Msr.Bits.SevSnpBit ? TRUE : FALSE;
}
/**
Returns a boolean to indicate whether SEV-ES is enabled.
@retval TRUE SEV-ES is enabled
@retval FALSE SEV-ES is not enabled
**/
BOOLEAN
EFIAPI
MemEncryptSevEsIsEnabled (
VOID
)
{
MSR_SEV_STATUS_REGISTER Msr;
Msr.Uint32 = InternalMemEncryptSevStatus ();
return Msr.Bits.SevEsBit ? TRUE : FALSE;
}
/**
Returns a boolean to indicate whether SEV is enabled.
@retval TRUE SEV is enabled
@retval FALSE SEV is not enabled
**/
BOOLEAN
EFIAPI
MemEncryptSevIsEnabled (
VOID
)
{
MSR_SEV_STATUS_REGISTER Msr;
Msr.Uint32 = InternalMemEncryptSevStatus ();
return Msr.Bits.SevBit ? TRUE : FALSE;
}
/**
Returns the SEV encryption mask.
@return The SEV pagtable encryption mask
**/
UINT64
EFIAPI
MemEncryptSevGetEncryptionMask (
VOID
)
{
SEC_SEV_ES_WORK_AREA *SevEsWorkArea;
SevEsWorkArea = GetSevEsWorkArea ();
if (SevEsWorkArea == NULL) {
return 0;
}
return SevEsWorkArea->EncryptionMask;
}
/**
Locate the page range that covers the initial (pre-SMBASE-relocation) SMRAM
Save State Map.
@param[out] BaseAddress The base address of the lowest-address page that
covers the initial SMRAM Save State Map.
@param[out] NumberOfPages The number of pages in the page range that covers
the initial SMRAM Save State Map.
@retval RETURN_SUCCESS BaseAddress and NumberOfPages have been set on
output.
@retval RETURN_UNSUPPORTED SMM is unavailable.
**/
RETURN_STATUS
EFIAPI
MemEncryptSevLocateInitialSmramSaveStateMapPages (
OUT UINTN *BaseAddress,
OUT UINTN *NumberOfPages
)
{
return RETURN_UNSUPPORTED;
}