OvmfPkg/IntelTdx/TdxMeasurementLib/SecPeiTdxMeasurement.c

/** @file
  TdxMeasurement Functions which are used in SEC and PEI phase

  Copyright (c) 2025, Intel Corporation. All rights reserved.<BR>

  SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include <PiPei.h>
#include <Pi/PiHob.h>
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/HobLib.h>
#include <Library/BaseMemoryLib.h>
#include <IndustryStandard/Tpm20.h>
#include <IndustryStandard/UefiTcgPlatform.h>
#include <Library/TdxMeasurementLib.h>

/**
 * Build GuidHob for Tdx measurement.
 *
 * Tdx measurement includes the measurement of TdHob and CFV. They're measured
 * and extended to RTMR registers in SEC phase. Because at that moment the Hob
 * service are not available. So the values of the measurement are saved in
 * workarea and will be built into GuidHob after the Hob service is ready.
 *
 * @param RtmrIndex     RTMR index
 * @param EventType     Event type
 * @param EventData     Event data
 * @param EventSize     Size of event data
 * @param HashValue     Hash value
 * @param HashSize      Size of hash
 *
 * @retval EFI_SUCCESS  Successfully build the GuidHobs
 * @retval Others       Other error as indicated
 */
EFI_STATUS
EFIAPI
TdxMeasurementBuildGuidHob (
  UINT32  RtmrIndex,
  UINT32  EventType,
  UINT8   *EventData,
  UINT32  EventSize,
  UINT8   *HashValue,
  UINT32  HashSize
  )
{
  VOID                *EventHobData;
  UINT8               *Ptr;
  TPML_DIGEST_VALUES  *TdxDigest;

  if (HashSize != SHA384_DIGEST_SIZE) {
    return EFI_INVALID_PARAMETER;
  }

  #define TDX_DIGEST_VALUE_LEN  (sizeof (UINT32) + sizeof (TPMI_ALG_HASH) + SHA384_DIGEST_SIZE)

  EventHobData = BuildGuidHob (
                   &gCcEventEntryHobGuid,
                   sizeof (TCG_PCRINDEX) + sizeof (TCG_EVENTTYPE) +
                   TDX_DIGEST_VALUE_LEN +
                   sizeof (UINT32) + EventSize
                   );

  if (EventHobData == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  Ptr = (UINT8 *)EventHobData;

  //
  // There are 2 types of measurement registers in TDX: MRTD and RTMR[0-3].
  // According to UEFI Spec 2.10 Section 38.4.1, RTMR[0-3] is mapped to MrIndex[1-4].
  // So RtmrIndex must be increased by 1 before the event log is created.
  //
  RtmrIndex++;
  CopyMem (Ptr, &RtmrIndex, sizeof (UINT32));
  Ptr += sizeof (UINT32);

  CopyMem (Ptr, &EventType, sizeof (TCG_EVENTTYPE));
  Ptr += sizeof (TCG_EVENTTYPE);

  TdxDigest                     = (TPML_DIGEST_VALUES *)Ptr;
  TdxDigest->count              = 1;
  TdxDigest->digests[0].hashAlg = TPM_ALG_SHA384;
  CopyMem (
    TdxDigest->digests[0].digest.sha384,
    HashValue,
    SHA384_DIGEST_SIZE
    );
  Ptr += TDX_DIGEST_VALUE_LEN;

  CopyMem (Ptr, &EventSize, sizeof (UINT32));
  Ptr += sizeof (UINT32);

  CopyMem (Ptr, (VOID *)EventData, EventSize);
  Ptr += EventSize;

  return EFI_SUCCESS;
}