BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275
The VMM launch sequence should have pre-validated all the data pages used
in the Reset vector. The range does not cover the data pages used during
the SEC phase (mainly PEI and DXE firmware volume decompression memory).
When SEV-SNP is active, the memory must be pre-validated before the access.
Add support to pre-validate the memory range from SnpSecPreValidatedStart
to SnpSecPreValidatedEnd. This should be sufficent to enter into the PEI
phase.
Cc: Michael Roth <michael.r...@amd.com>
Cc: James Bottomley <j...@linux.ibm.com>
Cc: Min Xu <min.m...@intel.com>
Cc: Jiewen Yao <jiewen....@intel.com>
Cc: Tom Lendacky <thomas.lenda...@amd.com>
Cc: Jordan Justen <jordan.l.jus...@intel.com>
Cc: Ard Biesheuvel <ardb+tianoc...@kernel.org>
Cc: Erdem Aktas <erdemak...@google.com>
Cc: Gerd Hoffmann <kra...@redhat.com>
Acked-by: Jiewen Yao <jiewen....@intel.com>
Acked-by: Gerd Hoffmann <kra...@redhat.com>
Signed-off-by: Brijesh Singh <brijesh.si...@amd.com>
---
OvmfPkg/OvmfPkg.dec | 4 ++++
.../PeiMemEncryptSevLib.inf | 2 ++
OvmfPkg/Sec/SecMain.inf | 3 +++
OvmfPkg/Sec/AmdSev.h | 23 +++++++++++++++++++
.../X64/PeiSnpSystemRamValidate.c | 5 ++++
OvmfPkg/Sec/AmdSev.c | 22 +++++++++++++++++-
OvmfPkg/Sec/SecMain.c | 5 ++++
OvmfPkg/FvmainCompactScratchEnd.fdf.inc | 5 ++++
8 files changed, 68 insertions(+), 1 deletion(-)
diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
index bc14cf2ed403..c22b846cd663 100644
--- a/OvmfPkg/OvmfPkg.dec
+++ b/OvmfPkg/OvmfPkg.dec
@@ -364,6 +364,10 @@ [PcdsFixedAtBuild]
gUefiOvmfPkgTokenSpaceGuid.PcdOvmfCpuidBase|0|UINT32|0x60
gUefiOvmfPkgTokenSpaceGuid.PcdOvmfCpuidSize|0|UINT32|0x61
+ ## The range of memory that is validated by the SEC phase.
+ gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecValidatedStart|0|UINT32|0x62
+ gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecValidatedEnd|0|UINT32|0x63
+
[PcdsDynamic, PcdsDynamicEx]
gUefiOvmfPkgTokenSpaceGuid.PcdEmuVariableEvent|0|UINT64|2
gUefiOvmfPkgTokenSpaceGuid.PcdOvmfFlashVariablesEnable|FALSE|BOOLEAN|0x10
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf
b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf
index 49d5bd1beff1..50c83859d7e7 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf
@@ -60,3 +60,5 @@ [FixedPcd]
gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase
gUefiOvmfPkgTokenSpaceGuid.PcdOvmfPeiMemFvBase
gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPageTablesBase
+ gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecValidatedEnd
+ gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecValidatedStart
diff --git a/OvmfPkg/Sec/SecMain.inf b/OvmfPkg/Sec/SecMain.inf
index 9523a8ea6c8f..282e60a2764f 100644
--- a/OvmfPkg/Sec/SecMain.inf
+++ b/OvmfPkg/Sec/SecMain.inf
@@ -51,6 +51,7 @@ [LibraryClasses]
PeCoffExtraActionLib
ExtractGuidedSectionLib
LocalApicLib
+ MemEncryptSevLib
CpuExceptionHandlerLib
[Ppis]
@@ -73,6 +74,8 @@ [Pcd]
gEfiMdeModulePkgTokenSpaceGuid.PcdInitValueInTempStack
gUefiOvmfPkgTokenSpaceGuid.PcdOvmfConfidentialComputingWorkAreaHeader
gUefiOvmfPkgTokenSpaceGuid.PcdOvmfWorkAreaBase
+ gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecValidatedStart
+ gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecValidatedEnd
[FeaturePcd]
gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire
diff --git a/OvmfPkg/Sec/AmdSev.h b/OvmfPkg/Sec/AmdSev.h
index adad96d23189..411bbedae4cf 100644
--- a/OvmfPkg/Sec/AmdSev.h
+++ b/OvmfPkg/Sec/AmdSev.h
@@ -69,4 +69,27 @@ SevEsIsEnabled (
VOID
);
+/**
+ Validate System RAM used for decompressing the PEI and DXE firmware volumes
+ when SEV-SNP is active. The PCDs SecValidatedStart and SecValidatedEnd are
+ set in OvmfPkg/FvmainCompactScratchEnd.fdf.inc.
+
+**/
+VOID
+SecValidateSystemRam (
+ VOID
+ );
+
+/**
+ Determine if SEV-SNP is active.
+
+ @retval TRUE SEV-SNP is enabled
+ @retval FALSE SEV-SNP is not enabled
+
+**/
+BOOLEAN
+SevSnpIsEnabled (
+ VOID
+ );
+
#endif
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiSnpSystemRamValidate.c
b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiSnpSystemRamValidate.c
index ee8b5bc8011f..d3ed8edecb03 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiSnpSystemRamValidate.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiSnpSystemRamValidate.c
@@ -29,6 +29,11 @@ STATIC SNP_PRE_VALIDATED_RANGE mPreValidatedRange[] = {
FixedPcdGet32 (PcdOvmfSecPageTablesBase),
FixedPcdGet32 (PcdOvmfPeiMemFvBase),
},
+ // The below range is pre-validated by the Sec/SecMain.c
+ {
+ FixedPcdGet32 (PcdOvmfSecValidatedStart),
+ FixedPcdGet32 (PcdOvmfSecValidatedEnd)
+ },
};
STATIC
diff --git a/OvmfPkg/Sec/AmdSev.c b/OvmfPkg/Sec/AmdSev.c
index 58f054ea4418..c419f7a8a7c2 100644
--- a/OvmfPkg/Sec/AmdSev.c
+++ b/OvmfPkg/Sec/AmdSev.c
@@ -55,7 +55,6 @@ SevEsProtocolFailure (
@retval FALSE SEV-SNP is not enabled
**/
-STATIC
BOOLEAN
SevSnpIsEnabled (
VOID
@@ -276,3 +275,24 @@ SevEsIsEnabled (
return (SevEsWorkArea->SevEsEnabled != 0);
}
+
+/**
+ Validate System RAM used for decompressing the PEI and DXE firmware volumes
+ when SEV-SNP is active. The PCDs SecValidatedStart and SecValidatedEnd are
+ set in OvmfPkg/FvmainCompactScratchEnd.fdf.inc.
+
+**/
+VOID
+SecValidateSystemRam (
+ VOID
+ )
+{
+ PHYSICAL_ADDRESS Start, End;
+
+ if (IsSevGuest () && SevSnpIsEnabled ()) {
+ Start = (EFI_PHYSICAL_ADDRESS) (UINTN) PcdGet32 (PcdOvmfSecValidatedStart);
+ End = (EFI_PHYSICAL_ADDRESS) (UINTN) PcdGet32 (PcdOvmfSecValidatedEnd);
+
+ MemEncryptSevSnpPreValidateSystemRam (Start, EFI_SIZE_TO_PAGES ((UINTN)
(End - Start)));
+ }
+}
diff --git a/OvmfPkg/Sec/SecMain.c b/OvmfPkg/Sec/SecMain.c
index 406e3a25d0cd..b173ff976073 100644
--- a/OvmfPkg/Sec/SecMain.c
+++ b/OvmfPkg/Sec/SecMain.c
@@ -847,6 +847,11 @@ SecCoreStartupWithStack (
SecCoreData.BootFirmwareVolumeBase = BootFv;
SecCoreData.BootFirmwareVolumeSize = (UINTN) BootFv->FvLength;
+ //
+ // Validate the System RAM used in the SEC Phase
+ //
+ SecValidateSystemRam ();
+
//
// Make sure the 8259 is masked before initializing the Debug Agent and the
debug timer is enabled
//
diff --git a/OvmfPkg/FvmainCompactScratchEnd.fdf.inc
b/OvmfPkg/FvmainCompactScratchEnd.fdf.inc
index 46f52583297c..d8d45fc9aa6d 100644
--- a/OvmfPkg/FvmainCompactScratchEnd.fdf.inc
+++ b/OvmfPkg/FvmainCompactScratchEnd.fdf.inc
@@ -63,3 +63,8 @@
DEFINE DECOMP_SCRATCH_BASE = (($(DECOMP_SCRATCH_BASE_UNALIGNED) +
$(DECOMP_SCRATCH_BASE_ALIGNMENT)) & $(DECOMP_SCRATCH_BASE_MASK))
SET gUefiOvmfPkgTokenSpaceGuid.PcdOvmfDecompressionScratchEnd =
$(DECOMP_SCRATCH_BASE) + $(DECOMP_SCRATCH_SIZE)
+
+#
+# The range of pages that should be pre-validated during the SEC phase when
SEV-SNP is active in the guest VM.
+SET gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecValidatedStart =
$(MEMFD_BASE_ADDRESS) + gUefiOvmfPkgTokenSpaceGuid.PcdOvmfPeiMemFvBase
+SET gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecValidatedEnd = $(DECOMP_SCRATCH_BASE)
+ $(DECOMP_SCRATCH_SIZE)
--
2.25.1
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