MdePkg: Introduce basic Tdx functions in BaseLib

[mirror_edk2.git] / MdePkg / Library / BaseLib / X64 / TdProbe.c

/** @file\r
\r
  Copyright (c) 2020-2021, Intel Corporation. All rights reserved.<BR>\r
  SPDX-License-Identifier: BSD-2-Clause-Patent\r
\r
**/\r
\r
#include <Library/BaseLib.h>\r
#include <Register/Intel/Cpuid.h>\r
\r
/**\r
  Probe if TD is enabled.\r
\r
  @return TRUE    TD is enabled.\r
  @return FALSE   TD is not enabled.\r
**/\r
BOOLEAN\r
EFIAPI\r
TdIsEnabled (\r
  )\r
{\r
  UINT32                  Eax;\r
  UINT32                  Ebx;\r
  UINT32                  Ecx;\r
  UINT32                  Edx;\r
  UINT32                  LargestEax;\r
  BOOLEAN                 TdEnabled;\r
  CPUID_VERSION_INFO_ECX  CpuIdVersionInfoEcx;\r
\r
  TdEnabled = FALSE;\r
\r
  do {\r
    AsmCpuid (CPUID_SIGNATURE, &LargestEax, &Ebx, &Ecx, &Edx);\r
\r
    if (  (Ebx != CPUID_SIGNATURE_GENUINE_INTEL_EBX)\r
       || (Edx != CPUID_SIGNATURE_GENUINE_INTEL_EDX)\r
       || (Ecx != CPUID_SIGNATURE_GENUINE_INTEL_ECX))\r
    {\r
      break;\r
    }\r
\r
    AsmCpuid (CPUID_VERSION_INFO, NULL, NULL, &CpuIdVersionInfoEcx.Uint32, NULL);\r
    if (CpuIdVersionInfoEcx.Bits.ParaVirtualized == 0) {\r
      break;\r
    }\r
\r
    if (LargestEax < CPUID_GUESTTD_RUNTIME_ENVIRONMENT) {\r
      break;\r
    }\r
\r
    AsmCpuidEx (CPUID_GUESTTD_RUNTIME_ENVIRONMENT, 0, &Eax, &Ebx, &Ecx, &Edx);\r
    if (  (Ebx != CPUID_GUESTTD_SIGNATURE_GENUINE_INTEL_EBX)\r
       || (Edx != CPUID_GUESTTD_SIGNATURE_GENUINE_INTEL_EDX)\r
       || (Ecx != CPUID_GUESTTD_SIGNATURE_GENUINE_INTEL_ECX))\r
    {\r
      break;\r
    }\r
\r
    TdEnabled = TRUE;\r
  } while (FALSE);\r
\r
  return TdEnabled;\r
}\r