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diff --git a/UefiCpuPkg/MicrocodeMeasurementDxe/MicrocodeMeasurementDxe.c b/UefiCpuPkg/MicrocodeMeasurementDxe/MicrocodeMeasurementDxe.c
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+/** @file
+ This driver measures microcode patches to TPM.
+
+ This driver consumes gEdkiiMicrocodePatchHobGuid, packs all unique microcode patch found in gEdkiiMicrocodePatchHobGuid to a binary blob, and measures the binary blob to TPM.
+
+ Copyright (c) 2021, Intel Corporation. All rights reserved.<BR>
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <IndustryStandard/UefiTcgPlatform.h>
+#include <Guid/EventGroup.h>
+#include <Guid/MicrocodePatchHob.h>
+#include <Library/DebugLib.h>
+#include <Library/UefiDriverEntryPoint.h>
+#include <Library/UefiLib.h>
+#include <Library/BaseLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/HobLib.h>
+#include <Library/MicrocodeLib.h>
+#include <Library/TpmMeasurementLib.h>
+
+#define CPU_MICROCODE_MEASUREMENT_DESCRIPTION "Microcode Measurement"
+#define CPU_MICROCODE_MEASUREMENT_EVENT_LOG_DESCRIPTION_LEN sizeof (CPU_MICROCODE_MEASUREMENT_DESCRIPTION)
+
+#pragma pack(1)
+typedef struct {
+ UINT8 Description[CPU_MICROCODE_MEASUREMENT_EVENT_LOG_DESCRIPTION_LEN];
+ UINTN NumberOfMicrocodePatchesMeasured;
+ UINTN SizeOfMicrocodePatchesMeasured;
+} CPU_MICROCODE_MEASUREMENT_EVENT_LOG;
+#pragma pack()
+
+/**
+ Helping function.
+
+ The function is called by QuickSort to compare the order of offsets of
+ two microcode patches in RAM relative to their base address. Elements
+ will be in ascending order.
+
+ @param[in] Offset1 The pointer to the offset of first microcode patch.
+ @param[in] Offset2 The pointer to the offset of second microcode patch.
+
+ @retval 1 The offset of first microcode patch is bigger than that of the second.
+ @retval -1 The offset of first microcode patch is smaller than that of the second.
+ @retval 0 The offset of first microcode patch equals to that of the second.
+**/
+INTN
+EFIAPI
+MicrocodePatchOffsetCompareFunction (
+ IN CONST VOID *Offset1,
+ IN CONST VOID *Offset2
+ )
+{
+ if (*(UINT64 *)(Offset1) > *(UINT64 *)(Offset2)) {
+ return 1;
+ } else if (*(UINT64 *)(Offset1) < *(UINT64 *)(Offset2)) {
+ return -1;
+ } else {
+ return 0;
+ }
+}
+
+/**
+ This function remove duplicate and invalid offsets in Offsets.
+
+ This function remove duplicate and invalid offsets in Offsets. Invalid offset means MAX_UINT64 in Offsets.
+
+ @param[in] Offsets Microcode offset list.
+ @param[in, out] Count On call as the count of raw microcode offset list; On return as count of the clean microcode offset list.
+ **/
+VOID
+RemoveDuplicateAndInvalidOffset (
+ IN UINT64 *Offsets,
+ IN OUT UINTN *Count
+ )
+{
+ UINTN Index;
+ UINTN NewCount;
+ UINT64 LastOffset;
+ UINT64 QuickSortBuffer;
+
+ //
+ // The order matters when packing all applied microcode patches to a single binary blob.
+ // Therefore it is a must to do sorting before packing.
+ // NOTE: Since microcode patches are sorted by their addresses in memory, the order of
+ // addresses in memory of all the microcode patches before sorting is required to be the
+ // same in every boot flow. If any future updates made this assumption untenable, then
+ // there needs a new solution to measure microcode patches.
+ //
+ QuickSort (
+ Offsets,
+ *Count,
+ sizeof (UINT64),
+ MicrocodePatchOffsetCompareFunction,
+ (VOID *)&QuickSortBuffer
+ );
+
+ NewCount = 0;
+ LastOffset = MAX_UINT64;
+ for (Index = 0; Index < *Count; Index++) {
+ //
+ // When MAX_UINT64 element is met, all following elements are MAX_UINT64.
+ //
+ if (Offsets[Index] == MAX_UINT64) {
+ break;
+ }
+
+ //
+ // Remove duplicated offsets
+ //
+ if (Offsets[Index] != LastOffset) {
+ LastOffset = Offsets[Index];
+ Offsets[NewCount] = Offsets[Index];
+ NewCount++;
+ }
+ }
+
+ *Count = NewCount;
+}
+
+/**
+ Callback function.
+
+ Called after signaling of the Ready to Boot Event. Measure microcode patches binary blob with event type EV_CPU_MICROCODE to PCR[1] in TPM.
+
+ @param[in] Event Event whose notification function is being invoked.
+ @param[in] Context Pointer to the notification function's context.
+
+**/
+VOID
+EFIAPI
+MeasureMicrocodePatches (
+ IN EFI_EVENT Event,
+ IN VOID *Context
+ )
+{
+ EFI_STATUS Status;
+ UINT32 PCRIndex;
+ UINT32 EventType;
+ CPU_MICROCODE_MEASUREMENT_EVENT_LOG EventLog;
+ UINT32 EventLogSize;
+ EFI_HOB_GUID_TYPE *GuidHob;
+ EDKII_MICROCODE_PATCH_HOB *MicrocodePatchHob;
+ UINT64 *Offsets;
+ UINTN Count;
+ UINTN Index;
+ UINTN TotalMicrocodeSize;
+ UINT8 *MicrocodePatchesBlob;
+
+ PCRIndex = 1;
+ EventType = EV_CPU_MICROCODE;
+ AsciiStrCpyS (
+ (CHAR8 *)(EventLog.Description),
+ CPU_MICROCODE_MEASUREMENT_EVENT_LOG_DESCRIPTION_LEN,
+ CPU_MICROCODE_MEASUREMENT_DESCRIPTION
+ );
+ EventLog.NumberOfMicrocodePatchesMeasured = 0;
+ EventLog.SizeOfMicrocodePatchesMeasured = 0;
+ EventLogSize = sizeof (CPU_MICROCODE_MEASUREMENT_EVENT_LOG);
+ Offsets = NULL;
+ TotalMicrocodeSize = 0;
+ Count = 0;
+
+ GuidHob = GetFirstGuidHob (&gEdkiiMicrocodePatchHobGuid);
+ if (NULL == GuidHob) {
+ DEBUG ((DEBUG_ERROR, "ERROR: GetFirstGuidHob (&gEdkiiMicrocodePatchHobGuid) failed.\n"));
+ return;
+ }
+
+ MicrocodePatchHob = GET_GUID_HOB_DATA (GuidHob);
+ DEBUG (
+ (DEBUG_INFO,
+ "INFO: Got MicrocodePatchHob with microcode patches starting address:0x%x, microcode patches region size:0x%x, processor count:0x%x\n",
+ MicrocodePatchHob->MicrocodePatchAddress, MicrocodePatchHob->MicrocodePatchRegionSize,
+ MicrocodePatchHob->ProcessorCount)
+ );
+
+ Offsets = AllocateCopyPool (
+ MicrocodePatchHob->ProcessorCount * sizeof (UINT64),
+ MicrocodePatchHob->ProcessorSpecificPatchOffset
+ );
+ Count = MicrocodePatchHob->ProcessorCount;
+
+ RemoveDuplicateAndInvalidOffset (Offsets, &Count);
+
+ if (0 == Count) {
+ DEBUG ((DEBUG_INFO, "INFO: No microcode patch is ever applied, skip the measurement of microcode!\n"));
+ FreePool (Offsets);
+ return;
+ }
+
+ for (Index = 0; Index < Count; Index++) {
+ TotalMicrocodeSize +=
+ GetMicrocodeLength ((CPU_MICROCODE_HEADER *)((UINTN)(MicrocodePatchHob->MicrocodePatchAddress + Offsets[Index])));
+ }
+
+ EventLog.NumberOfMicrocodePatchesMeasured = Count;
+ EventLog.SizeOfMicrocodePatchesMeasured = TotalMicrocodeSize;
+
+ MicrocodePatchesBlob = AllocateZeroPool (TotalMicrocodeSize);
+ if (NULL == MicrocodePatchesBlob) {
+ DEBUG ((DEBUG_ERROR, "ERROR: AllocateZeroPool to MicrocodePatchesBlob failed!\n"));
+ FreePool (Offsets);
+ return;
+ }
+
+ TotalMicrocodeSize = 0;
+ for (Index = 0; Index < Count; Index++) {
+ CopyMem (
+ (VOID *)(MicrocodePatchesBlob + TotalMicrocodeSize),
+ (VOID *)((UINTN)(MicrocodePatchHob->MicrocodePatchAddress + Offsets[Index])),
+ (UINTN)(GetMicrocodeLength (
+ (CPU_MICROCODE_HEADER *)((UINTN)(MicrocodePatchHob->MicrocodePatchAddress +
+ Offsets[Index]))
+ ))
+ );
+ TotalMicrocodeSize +=
+ GetMicrocodeLength ((CPU_MICROCODE_HEADER *)((UINTN)(MicrocodePatchHob->MicrocodePatchAddress + Offsets[Index])));
+ }
+
+ Status = TpmMeasureAndLogData (
+ PCRIndex, // PCRIndex
+ EventType, // EventType
+ &EventLog, // EventLog
+ EventLogSize, // LogLen
+ MicrocodePatchesBlob, // HashData
+ TotalMicrocodeSize // HashDataLen
+ );
+ if (!EFI_ERROR (Status)) {
+ gBS->CloseEvent (Event);
+ DEBUG (
+ (DEBUG_INFO,
+ "INFO: %d Microcode patches are successfully extended to TPM! The total size measured to TPM is 0x%x\n",
+ Count,
+ TotalMicrocodeSize)
+ );
+ } else {
+ DEBUG ((DEBUG_ERROR, "ERROR: TpmMeasureAndLogData failed with status %a!\n", Status));
+ }
+
+ FreePool (Offsets);
+ FreePool (MicrocodePatchesBlob);
+ return;
+}
+
+/**
+
+ Driver to produce microcode measurement.
+
+ Driver to produce microcode measurement. Which install a callback function on ready to boot event.
+
+ @param ImageHandle Module's image handle
+ @param SystemTable Pointer of EFI_SYSTEM_TABLE
+
+ @return EFI_SUCCESS This function always complete successfully.
+
+**/
+EFI_STATUS
+EFIAPI
+MicrocodeMeasurementDriverEntryPoint (
+ IN EFI_HANDLE ImageHandle,
+ IN EFI_SYSTEM_TABLE *SystemTable
+ )
+{
+ EFI_EVENT Event;
+
+ //
+ // Measure Microcode patches
+ //
+ EfiCreateEventReadyToBootEx (
+ TPL_CALLBACK,
+ MeasureMicrocodePatches,
+ NULL,
+ &Event
+ );
+
+ return EFI_SUCCESS;
+}