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>
Signed-off-by: Brijesh Singh <brijesh.si...@amd.com>
---
OvmfPkg/OvmfPkg.dec | 5 ++++
.../PeiMemEncryptSevLib.inf | 2 ++
OvmfPkg/Sec/SecMain.inf | 3 +++
OvmfPkg/Sec/AmdSev.h | 23 +++++++++++++++++++
.../X64/PeiSnpSystemRamValidate.c | 5 ++++
OvmfPkg/Sec/AmdSev.c | 20 +++++++++++++++-
OvmfPkg/Sec/SecMain.c | 7 ++++++
OvmfPkg/FvmainCompactScratchEnd.fdf.inc | 5 ++++
8 files changed, 69 insertions(+), 1 deletion(-)
diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
index efa0de6d0600..e30cb6eafcb8 100644
--- a/OvmfPkg/OvmfPkg.dec
+++ b/OvmfPkg/OvmfPkg.dec
@@ -354,6 +354,11 @@ [PcdsFixedAtBuild]
gUefiOvmfPkgTokenSpaceGuid.PcdOvmfCpuidBase|0|UINT32|0x54
gUefiOvmfPkgTokenSpaceGuid.PcdOvmfCpuidSize|0|UINT32|0x55
+ ## The range of memory that need to be pre-validated in the SEC phase
+ # when SEV-SNP is active in the guest VM.
+ gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecPreValidatedStart|0|UINT32|0x56
+ gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecPreValidatedEnd|0|UINT32|0x57
+
[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 1cc9dd6691a2..01764ab3a1a8 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf
@@ -78,3 +78,5 @@ [FixedPcd]
gUefiOvmfPkgTokenSpaceGuid.PcdOvmfLockBoxStorageSize
gEfiMdePkgTokenSpaceGuid.PcdGuidedExtractHandlerTableAddress
gUefiOvmfPkgTokenSpaceGuid.PcdGuidedExtractHandlerTableSize
+ gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecPreValidatedEnd
+ gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecPreValidatedStart
diff --git a/OvmfPkg/Sec/SecMain.inf b/OvmfPkg/Sec/SecMain.inf
index 9523a8ea6c8f..7e2668ff2f66 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.PcdOvmfSnpSecPreValidatedStart
+ gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecPreValidatedEnd
[FeaturePcd]
gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire
diff --git a/OvmfPkg/Sec/AmdSev.h b/OvmfPkg/Sec/AmdSev.h
index adad96d23189..33af32b9925b 100644
--- a/OvmfPkg/Sec/AmdSev.h
+++ b/OvmfPkg/Sec/AmdSev.h
@@ -69,4 +69,27 @@ SevEsIsEnabled (
VOID
);
+/**
+ Pre-validate System RAM used for decompressing the PEI and DXE firmware
volumes
+ when SEV-SNP is active. The PCDs SecPreValidatedStart and SecPreValidatedEnd
are
+ set in OvmfPkg/FvmainCompactScratchEnd.fdf.inc.
+
+**/
+VOID
+SevSnpSecPreValidateSystemRam (
+ 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 a0803e1255dc..c51d565fc176 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiSnpSystemRamValidate.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiSnpSystemRamValidate.c
@@ -65,6 +65,11 @@ STATIC SNP_PRE_VALIDATED_RANGE mPreValidatedRange[] = {
FixedPcdGet32 (PcdOvmfSecPeiTempRamBase),
FixedPcdGet32 (PcdOvmfSecPeiTempRamBase) + FixedPcdGet32
(PcdOvmfSecPeiTempRamSize),
},
+ // The below range is pre-validated by the Sec/SecMain.c
+ {
+ FixedPcdGet32 (PcdOvmfSnpSecPreValidatedStart),
+ FixedPcdGet32 (PcdOvmfSnpSecPreValidatedEnd)
+ },
};
STATIC
diff --git a/OvmfPkg/Sec/AmdSev.c b/OvmfPkg/Sec/AmdSev.c
index 7d4d7cc8a07c..e54a3fa23f6a 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
@@ -296,3 +295,22 @@ SevEsIsEnabled (
return (SevEsWorkArea->SevEsEnabled != 0);
}
+
+/**
+ Pre-validate System RAM used for decompressing the PEI and DXE firmware
volumes
+ when SEV-SNP is active. The PCDs SecPreValidatedStart and SecPreValidatedEnd
are
+ set in OvmfPkg/FvmainCompactScratchEnd.fdf.inc.
+
+**/
+VOID
+SevSnpSecPreValidateSystemRam (
+ VOID
+ )
+{
+ PHYSICAL_ADDRESS Start, End;
+
+ Start = (EFI_PHYSICAL_ADDRESS) PcdGet32 (PcdOvmfSnpSecPreValidatedStart);
+ End = (EFI_PHYSICAL_ADDRESS) PcdGet32 (PcdOvmfSnpSecPreValidatedEnd);
+
+ MemEncryptSevSnpPreValidateSystemRam (Start, EFI_SIZE_TO_PAGES (End -
Start));
+}
diff --git a/OvmfPkg/Sec/SecMain.c b/OvmfPkg/Sec/SecMain.c
index 406e3a25d0cd..0d80494b062c 100644
--- a/OvmfPkg/Sec/SecMain.c
+++ b/OvmfPkg/Sec/SecMain.c
@@ -847,6 +847,13 @@ SecCoreStartupWithStack (
SecCoreData.BootFirmwareVolumeBase = BootFv;
SecCoreData.BootFirmwareVolumeSize = (UINTN) BootFv->FvLength;
+ if (SevSnpIsEnabled ()) {
+ //
+ // Pre-validate the System RAM used in the SEC Phase
+ //
+ SevSnpSecPreValidateSystemRam ();
+ }
+
//
// 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..b560fb0b8e4f 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.PcdOvmfSnpSecPreValidatedStart =
$(MEMFD_BASE_ADDRESS) + gUefiOvmfPkgTokenSpaceGuid.PcdOvmfPeiMemFvBase
+SET gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecPreValidatedEnd =
$(DECOMP_SCRATCH_BASE) + $(DECOMP_SCRATCH_SIZE)
--
2.17.1
-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#80597): https://edk2.groups.io/g/devel/message/80597
Mute This Topic: https://groups.io/mt/85582706/21656
Group Owner: devel+ow...@edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com]
-=-=-=-=-=-=-=-=-=-=-=-
