TdProbe.c

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#include <Library/BaseLib.h>
#include <Register/Intel/Cpuid.h>
 
BOOLEAN
EFIAPI
TdIsEnabled (
  )
{
  UINT32                  Eax;
  UINT32                  Ebx;
  UINT32                  Ecx;
  UINT32                  Edx;
  UINT32                  LargestEax;
  BOOLEAN                 TdEnabled;
  CPUID_VERSION_INFO_ECX  CpuIdVersionInfoEcx;
 
  TdEnabled = FALSE;
 
  do {
    AsmCpuid (CPUID_SIGNATURE, &LargestEax, &Ebx, &Ecx, &Edx);
 
    if (  (Ebx != CPUID_SIGNATURE_GENUINE_INTEL_EBX)
       || (Edx != CPUID_SIGNATURE_GENUINE_INTEL_EDX)
       || (Ecx != CPUID_SIGNATURE_GENUINE_INTEL_ECX))
    {
      break;
    }
 
    AsmCpuid (CPUID_VERSION_INFO, NULL, NULL, &CpuIdVersionInfoEcx.Uint32, NULL);
    if (CpuIdVersionInfoEcx.Bits.ParaVirtualized == 0) {
      break;
    }
 
    if (LargestEax < CPUID_GUESTTD_RUNTIME_ENVIRONMENT) {
      break;
    }
 
    AsmCpuidEx (CPUID_GUESTTD_RUNTIME_ENVIRONMENT, 0, &Eax, &Ebx, &Ecx, &Edx);
    if (  (Ebx != CPUID_GUESTTD_SIGNATURE_GENUINE_INTEL_EBX)
       || (Edx != CPUID_GUESTTD_SIGNATURE_GENUINE_INTEL_EDX)
       || (Ecx != CPUID_GUESTTD_SIGNATURE_GENUINE_INTEL_ECX))
    {
      break;
    }
 
    TdEnabled = TRUE;
  } while (FALSE);
 
  return TdEnabled;
}