REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1020
The following Microcode payload format is define in SDM spec.
Payload: |MicrocodeHeader|MicrocodeBinary|ExtendedHeader|ExtendedTable|.
When we verify the CheckSum32 with ExtendedTable, we should use the fields
of ExtendedTable to replace corresponding fields in MicrocodeHeader,
and then calculate the CheckSum32 with MicrocodeHeader+MicrocodeBinary.
This patch already verified on ICL platform.
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Chen A Chen <chen.a.c...@intel.com>
Cc: Ray Ni <ray...@intel.com>
Cc: Eric Dong <eric.d...@intel.com>
Cc: Zhang Chao B <chao.b.zh...@intel.com>
---
UefiCpuPkg/Library/MpInitLib/Microcode.c | 82 ++++++++++++++++++++++++++++----
1 file changed, 73 insertions(+), 9 deletions(-)
diff --git a/UefiCpuPkg/Library/MpInitLib/Microcode.c
b/UefiCpuPkg/Library/MpInitLib/Microcode.c
index d84344c6f5..e1f661d6b1 100644
--- a/UefiCpuPkg/Library/MpInitLib/Microcode.c
+++ b/UefiCpuPkg/Library/MpInitLib/Microcode.c
@@ -35,6 +35,42 @@ GetCurrentMicrocodeSignature (
/**
Detect whether specified processor can find matching microcode patch and
load it.
+ Microcode Payload as the following format:
+ +----------------------------------------+------------------+
+ | CPU_MICROCODE_HEADER | |
+ +----------------------------------------+ CheckSum Part1 |
+ | Microcode Binary | |
+ +----------------------------------------+------------------+
+ | CPU_MICROCODE_EXTENDED_TABLE_HEADER | |
+ +----------------------------------------+ CheckSum Part2 |
+ | CPU_MICROCODE_EXTENDED_TABLE | |
+ | ... | |
+ +----------------------------------------+------------------+
+
+ There may by multiple CPU_MICROCODE_EXTENDED_TABLE in this format.
+ The count of CPU_MICROCODE_EXTENDED_TABLE is indicated by
ExtendedSignatureCount
+ of CPU_MICROCODE_EXTENDED_TABLE_HEADER structure.
+
+ When we are trying to verify the CheckSum32 with extended table.
+ We should use the fields of exnteded table to replace the corresponding
+ fields in CPU_MICROCODE_HEADER structure, and recalculate the
+ CheckSum32 with CPU_MICROCODE_HEADER + Microcode Binary. We named
+ it as CheckSum Part3.
+
+ The CheckSum Part2 is used to verify the CPU_MICROCODE_EXTENDED_TABLE_HEADER
+ and CPU_MICROCODE_EXTENDED_TABLE parts. We should make sure CheckSum Part2
+ is correct before we are going to verify each CPU_MICROCODE_EXTENDED_TABLE.
+
+ Only ProcessorSignature, ProcessorFlag and CheckSum are different between
+ CheckSum Part1 and CheckSum Part3. To avoid multiple computing CheckSum
Part3.
+ Save an in-complete CheckSum32 from CheckSum Part1 for common parts.
+ When we are going to calculate CheckSum32, just should use the corresponding
part
+ of the ProcessorSignature, ProcessorFlag and CheckSum with in-complete
CheckSum32.
+
+ Notes: CheckSum32 is not a strong verification.
+ It does not guarantee that the data has not been modified.
+ CPU has its own mechanism to verify Microcode Binary part.
+
@param[in] CpuMpData The pointer to CPU MP Data structure.
@param[in] IsBspCallIn Indicate whether the caller is BSP or not.
**/
@@ -57,6 +93,7 @@ MicrocodeDetect (
UINT32 LatestRevision;
UINTN TotalSize;
UINT32 CheckSum32;
+ UINT32 InCompleteCheckSum32;
BOOLEAN CorrectMicrocode;
VOID *MicrocodeData;
MSR_IA32_PLATFORM_ID_REGISTER PlatformIdMsr;
@@ -121,6 +158,25 @@ MicrocodeDetect (
MicrocodeData = NULL;
MicrocodeEnd = (UINTN) (CpuMpData->MicrocodePatchAddress +
CpuMpData->MicrocodePatchRegionSize);
MicrocodeEntryPoint = (CPU_MICROCODE_HEADER *) (UINTN)
CpuMpData->MicrocodePatchAddress;
+
+ //
+ // Save an in-complete CheckSum32 from CheckSum Part1 for common parts.
+ //
+ if (MicrocodeEntryPoint->DataSize == 0) {
+ InCompleteCheckSum32 = CalculateSum32 (
+ (UINT32 *) MicrocodeEntryPoint,
+ sizeof (CPU_MICROCODE_HEADER) + 2000
+ );
+ } else {
+ InCompleteCheckSum32 = CalculateSum32 (
+ (UINT32 *) MicrocodeEntryPoint,
+ sizeof (CPU_MICROCODE_HEADER) +
MicrocodeEntryPoint->DataSize
+ );
+ }
+ InCompleteCheckSum32 -= MicrocodeEntryPoint->ProcessorSignature.Uint32;
+ InCompleteCheckSum32 -= MicrocodeEntryPoint->ProcessorFlags;
+ InCompleteCheckSum32 -= MicrocodeEntryPoint->Checksum;
+
do {
//
// Check if the microcode is for the Cpu and the version is newer
@@ -137,14 +193,13 @@ MicrocodeDetect (
MicrocodeEntryPoint->UpdateRevision > LatestRevision &&
(MicrocodeEntryPoint->ProcessorFlags & (1 << PlatformId))
) {
- if (MicrocodeEntryPoint->DataSize == 0) {
- CheckSum32 = CalculateSum32 ((UINT32 *) MicrocodeEntryPoint, 2048);
- } else {
- CheckSum32 = CalculateSum32 (
- (UINT32 *) MicrocodeEntryPoint,
- MicrocodeEntryPoint->DataSize + sizeof
(CPU_MICROCODE_HEADER)
- );
- }
+ //
+ // Calculate CheckSum Part1.
+ //
+ CheckSum32 = InCompleteCheckSum32;
+ CheckSum32 += MicrocodeEntryPoint->ProcessorSignature.Uint32;
+ CheckSum32 += MicrocodeEntryPoint->ProcessorFlags;
+ CheckSum32 += MicrocodeEntryPoint->Checksum;
if (CheckSum32 == 0) {
CorrectMicrocode = TRUE;
ProcessorFlags = MicrocodeEntryPoint->ProcessorFlags;
@@ -163,6 +218,9 @@ MicrocodeDetect (
// Calculate Extended Checksum
//
if ((ExtendedTableLength % 4) == 0) {
+ //
+ // Calculate CheckSum Part2.
+ //
CheckSum32 = CalculateSum32 ((UINT32 *) ExtendedTableHeader,
ExtendedTableLength);
if (CheckSum32 == 0) {
//
@@ -171,7 +229,13 @@ MicrocodeDetect (
ExtendedTableCount = ExtendedTableHeader->ExtendedSignatureCount;
ExtendedTable = (CPU_MICROCODE_EXTENDED_TABLE *)
(ExtendedTableHeader + 1);
for (Index = 0; Index < ExtendedTableCount; Index ++) {
- CheckSum32 = CalculateSum32 ((UINT32 *) ExtendedTable,
sizeof(CPU_MICROCODE_EXTENDED_TABLE));
+ //
+ // Calculate CheckSum Part3.
+ //
+ CheckSum32 = InCompleteCheckSum32;
+ CheckSum32 += ExtendedTable->ProcessorSignature.Uint32;
+ CheckSum32 += ExtendedTable->ProcessorFlag;
+ CheckSum32 += ExtendedTable->Checksum;
if (CheckSum32 == 0) {
//
// Verify Header
--
2.16.2.windows.1
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