diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf index 0402e49a10..49d5bd1bef 100644 --- a/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf +++ b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf @@ -58,3 +58,5 @@ [FixedPcd] gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase + gUefiOvmfPkgTokenSpaceGuid.PcdOvmfPeiMemFvBase + gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPageTablesBase diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiSnpSystemRamValidate.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiSnpSystemRamValidate.c index bc891c2636..2d2136f805 100644 --- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiSnpSystemRamValidate.c +++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiSnpSystemRamValidate.c @@ -14,6 +14,46 @@ #include "SnpPageStateChange.h" +typedef struct { + UINT64 StartAddress; + UINT64 EndAddress; +} SNP_PRE_VALIDATED_RANGE; + +STATIC SNP_PRE_VALIDATED_RANGE mPreValidatedRange[] = { + // The below address range was part of the SEV OVMF metadata, and range + // should be pre-validated by the Hypervisor. + { + FixedPcdGet32 (PcdOvmfSecPageTablesBase), + FixedPcdGet32 (PcdOvmfPeiMemFvBase), + }, +}; + +STATIC +BOOLEAN +DetectPreValidatedOverLap ( + IN PHYSICAL_ADDRESS StartAddress, + IN PHYSICAL_ADDRESS EndAddress, + OUT SNP_PRE_VALIDATED_RANGE *OverlapRange + ) +{ + UINTN i; + + // + // Check if the specified address range exist in pre-validated array. + // + for (i = 0; i < ARRAY_SIZE (mPreValidatedRange); i++) { + if ((mPreValidatedRange[i].StartAddress < EndAddress) && + (StartAddress < mPreValidatedRange[i].EndAddress)) + { + OverlapRange->StartAddress = mPreValidatedRange[i].StartAddress; + OverlapRange->EndAddress = mPreValidatedRange[i].EndAddress; + return TRUE; + } + } + + return FALSE; +} + /** Pre-validate the system RAM when SEV-SNP is enabled in the guest VM. @@ -28,9 +68,34 @@ MemEncryptSevSnpPreValidateSystemRam ( IN UINTN NumPages ) { + PHYSICAL_ADDRESS EndAddress; + SNP_PRE_VALIDATED_RANGE OverlapRange; + if (!MemEncryptSevSnpIsEnabled ()) { return; } - InternalSetPageState (BaseAddress, NumPages, SevSnpPagePrivate, TRUE); + EndAddress = BaseAddress + EFI_PAGES_TO_SIZE (NumPages); + + while (BaseAddress < EndAddress) { + // + // Check if the range overlaps with the pre-validated ranges. + // + if (DetectPreValidatedOverLap (BaseAddress, EndAddress, &OverlapRange)) { + // Validate the non-overlap regions. + if (BaseAddress < OverlapRange.StartAddress) { + NumPages = EFI_SIZE_TO_PAGES (OverlapRange.StartAddress - BaseAddress); + + InternalSetPageState (BaseAddress, NumPages, SevSnpPagePrivate, TRUE); + } + + BaseAddress = OverlapRange.EndAddress; + continue; + } + + // Validate the remaining pages. + NumPages = EFI_SIZE_TO_PAGES (EndAddress - BaseAddress); + InternalSetPageState (BaseAddress, NumPages, SevSnpPagePrivate, TRUE); + BaseAddress = EndAddress; + } }