MdePkg/Library/TdxLib/Rtmr.c

/** @file

  Extends one of the RTMR measurement registers in TDCS with the provided
  extension data in memory.

  Copyright (c) 2020 - 2021, Intel Corporation. All rights reserved.<BR>
  SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Uefi/UefiBaseType.h>
#include <Library/TdxLib.h>
#include <Library/BaseMemoryLib.h>
#include <IndustryStandard/Tpm20.h>
#include <IndustryStandard/Tdx.h>

#define RTMR_COUNT            4
#define TD_EXTEND_BUFFER_LEN  (64 + 48)

UINT8  mExtendBuffer[TD_EXTEND_BUFFER_LEN];

/**
  This function extends one of the RTMR measurement register
  in TDCS with the provided extension data in memory.
  RTMR extending supports SHA384 which length is 48 bytes.

  @param[in]  Data      Point to the data to be extended
  @param[in]  DataLen   Length of the data. Must be 48
  @param[in]  Index     RTMR index

  @return EFI_SUCCESS
  @return EFI_INVALID_PARAMETER
  @return EFI_DEVICE_ERROR

**/
EFI_STATUS
EFIAPI
TdExtendRtmr (
  IN  UINT32  *Data,
  IN  UINT32  DataLen,
  IN  UINT8   Index
  )
{
  EFI_STATUS  Status;
  UINT64      TdCallStatus;
  UINT8       *ExtendBuffer;

  Status = EFI_SUCCESS;

  ASSERT (Data != NULL);
  ASSERT (DataLen == SHA384_DIGEST_SIZE);
  ASSERT (Index < RTMR_COUNT);

  if ((Data == NULL) || (DataLen != SHA384_DIGEST_SIZE) || (Index >= RTMR_COUNT)) {
    return EFI_INVALID_PARAMETER;
  }

  // TD.RTMR.EXTEND requires 64B-aligned guest physical address of
  // 48B-extension data. We use ALIGN_POINTER(Pointer, 64) to get
  // the 64B-aligned guest physical address.
  ExtendBuffer = ALIGN_POINTER (mExtendBuffer, 64);
  ASSERT (((UINTN)ExtendBuffer & 0x3f) == 0);

  ZeroMem (ExtendBuffer, SHA384_DIGEST_SIZE);
  CopyMem (ExtendBuffer, Data, SHA384_DIGEST_SIZE);

  TdCallStatus = TdCall (TDCALL_TDEXTENDRTMR, (UINT64)(UINTN)ExtendBuffer, Index, 0, 0);

  if (TdCallStatus == TDX_EXIT_REASON_SUCCESS) {
    Status = EFI_SUCCESS;
  } else if (TdCallStatus == TDX_EXIT_REASON_OPERAND_INVALID) {
    Status = EFI_INVALID_PARAMETER;
  } else {
    Status = EFI_DEVICE_ERROR;
  }

  if (Status != EFI_SUCCESS) {
    DEBUG ((DEBUG_ERROR, "Error returned from TdExtendRtmr call - 0x%lx\n", TdCallStatus));
  }

  return Status;
}