DxeMemEncryptSevLibInternal.c

Go to the documentation of this file.

 
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/MemEncryptSevLib.h>
#include <Library/PcdLib.h>
#include <Register/Amd/Cpuid.h>
#include <Register/Amd/Msr.h>
#include <Register/Cpuid.h>
#include <Uefi/UefiBaseType.h>
#include <ConfidentialComputingGuestAttr.h>
 
STATIC UINT64   mCurrentAttr            = 0;
STATIC BOOLEAN  mCurrentAttrRead        = FALSE;
STATIC UINT64   mSevEncryptionMask      = 0;
STATIC BOOLEAN  mSevEncryptionMaskSaved = FALSE;
 
STATIC
BOOLEAN
AmdMemEncryptionAttrCheck (
  IN  UINT64                             CurrentAttr,
  IN  CONFIDENTIAL_COMPUTING_GUEST_ATTR  Attr
  )
{
  UINT64  CurrentLevel;
 
  CurrentLevel = CurrentAttr & CCAttrTypeMask;
 
  switch (Attr) {
    case CCAttrAmdSev:
      //
      // SEV is automatically enabled if SEV-ES or SEV-SNP is active.
      //
      return CurrentLevel >= CCAttrAmdSev;
    case CCAttrAmdSevEs:
      //
      // SEV-ES is automatically enabled if SEV-SNP is active.
      //
      return CurrentLevel >= CCAttrAmdSevEs;
    case CCAttrAmdSevSnp:
      return CurrentLevel == CCAttrAmdSevSnp;
    case CCAttrFeatureAmdSevEsDebugVirtualization:
      return !!(CurrentAttr & CCAttrFeatureAmdSevEsDebugVirtualization);
    default:
      return FALSE;
  }
}
 
STATIC
BOOLEAN
EFIAPI
ConfidentialComputingGuestHas (
  IN  CONFIDENTIAL_COMPUTING_GUEST_ATTR  Attr
  )
{
  //
  // Get the current CC attribute.
  //
  // We avoid reading the PCD on every check because this routine could be indirectly
  // called during the virtual pointer conversion. And its not safe to access the
  // PCDs during the virtual pointer conversion.
  //
  if (!mCurrentAttrRead) {
    mCurrentAttr     = PcdGet64 (PcdConfidentialComputingGuestAttr);
    mCurrentAttrRead = TRUE;
  }
 
  //
  // If attr is for the AMD group then call AMD specific checks.
  //
  if (((RShiftU64 (mCurrentAttr, 8)) & 0xff) == 1) {
    return AmdMemEncryptionAttrCheck (mCurrentAttr, Attr);
  }
 
  return (mCurrentAttr == Attr);
}
 
BOOLEAN
EFIAPI
MemEncryptSevSnpIsEnabled (
  VOID
  )
{
  return ConfidentialComputingGuestHas (CCAttrAmdSevSnp);
}
 
BOOLEAN
EFIAPI
MemEncryptSevEsIsEnabled (
  VOID
  )
{
  return ConfidentialComputingGuestHas (CCAttrAmdSevEs);
}
 
BOOLEAN
EFIAPI
MemEncryptSevIsEnabled (
  VOID
  )
{
  return ConfidentialComputingGuestHas (CCAttrAmdSev);
}
 
UINT64
EFIAPI
MemEncryptSevGetEncryptionMask (
  VOID
  )
{
  if (!mSevEncryptionMaskSaved) {
    mSevEncryptionMask      = PcdGet64 (PcdPteMemoryEncryptionAddressOrMask);
    mSevEncryptionMaskSaved = TRUE;
  }
 
  return mSevEncryptionMask;
}
 
BOOLEAN
EFIAPI
MemEncryptSevEsDebugVirtualizationIsEnabled (
  VOID
  )
{
  return ConfidentialComputingGuestHas (CCAttrFeatureAmdSevEsDebugVirtualization);
}