X86XenHypercall.c

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#include <PiDxe.h>
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/CpuLib.h>
 
static INTN     mUseVmmCall = -1;
static BOOLEAN  mHypercallAvail;
 
//
// Interface exposed by the ASM implementation of the core hypercall
//
INTN
EFIAPI
__XenVmmcall2 (
  IN     INTN  HypercallNum,
  IN OUT INTN  Arg1,
  IN OUT INTN  Arg2
  );
 
INTN
EFIAPI
__XenVmcall2 (
  IN     INTN  HypercallNum,
  IN OUT INTN  Arg1,
  IN OUT INTN  Arg2
  );
 
BOOLEAN
EFIAPI
XenHypercallIsAvailable (
  VOID
  )
{
  return mHypercallAvail;
}
 
STATIC
UINT32
XenCpuidLeaf (
  VOID
  )
{
  UINT8   Signature[13];
  UINT32  XenLeaf;
 
  Signature[12] = '\0';
  for (XenLeaf = 0x40000000; XenLeaf < 0x40010000; XenLeaf += 0x100) {
    AsmCpuid (
      XenLeaf,
      NULL,
      (UINT32 *)&Signature[0],
      (UINT32 *)&Signature[4],
      (UINT32 *)&Signature[8]
      );
 
    if (!AsciiStrCmp ((CHAR8 *)Signature, "XenVMMXenVMM")) {
      return XenLeaf;
    }
  }
 
  return 0;
}
 
RETURN_STATUS
EFIAPI
XenHypercallLibInit (
  VOID
  )
{
  UINT32  XenLeaf;
  CHAR8   sig[13];
 
  XenLeaf = XenCpuidLeaf ();
  if (XenLeaf == 0) {
    return RETURN_NOT_FOUND;
  }
 
  sig[12] = '\0';
  AsmCpuid (
    0,
    NULL,
    (UINT32 *)&sig[0],
    (UINT32 *)&sig[8],
    (UINT32 *)&sig[4]
    );
 
  DEBUG ((DEBUG_INFO, "Detected CPU \"%12a\"\n", sig));
 
  if ((AsciiStrCmp ("AuthenticAMD", sig) == 0) ||
      (AsciiStrCmp ("HygonGenuine", sig) == 0))
  {
    mUseVmmCall = TRUE;
  } else if ((AsciiStrCmp ("GenuineIntel", sig) == 0) ||
             (AsciiStrCmp ("CentaurHauls", sig) == 0) ||
             (AsciiStrCmp ("  Shanghai  ", sig) == 0))
  {
    mUseVmmCall = FALSE;
  } else {
    DEBUG ((DEBUG_ERROR, "Unsupported CPU vendor\n"));
    return RETURN_NOT_FOUND;
  }
 
  mHypercallAvail = TRUE;
 
  return RETURN_SUCCESS;
}
 
INTN
EFIAPI
XenHypercall2 (
  IN     UINTN  HypercallID,
  IN OUT INTN   Arg1,
  IN OUT INTN   Arg2
  )
{
  if (mUseVmmCall) {
    return __XenVmmcall2 (HypercallID, Arg1, Arg2);
  } else {
    return __XenVmcall2 (HypercallID, Arg1, Arg2);
  }
}