1 files changed, 121 insertions, 0 deletions
diff --git a/UefiCpuPkg/Library/VmgExitLibNull/VmgExitLibNull.c b/UefiCpuPkg/Library/VmgExitLibNull/VmgExitLibNull.c
new file mode 100644
index 0000000000..bb265e1700
--- /dev/null
+++ b/UefiCpuPkg/Library/VmgExitLibNull/VmgExitLibNull.c
@@ -0,0 +1,121 @@
+/** @file
+  VMGEXIT Base Support Library.
+
+  Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Base.h>
+#include <Uefi.h>
+#include <Library/VmgExitLib.h>
+
+/**
+  Perform VMGEXIT.
+
+  Sets the necessary fields of the GHCB, invokes the VMGEXIT instruction and
+  then handles the return actions.
+
+  The base library function returns an error in the form of a
+  GHCB_EVENT_INJECTION representing a GP_EXCEPTION.
+
+  @param[in, out]  Ghcb       A pointer to the GHCB
+  @param[in]       ExitCode   VMGEXIT code to be assigned to the SwExitCode
+                              field of the GHCB.
+  @param[in]       ExitInfo1  VMGEXIT information to be assigned to the
+                              SwExitInfo1 field of the GHCB.
+  @param[in]       ExitInfo2  VMGEXIT information to be assigned to the
+                              SwExitInfo2 field of the GHCB.
+
+  @retval  0                  VMGEXIT succeeded.
+  @return                     Exception number to be propagated, VMGEXIT
+                              processing did not succeed.
+
+**/
+UINT64
+EFIAPI
+VmgExit (
+  IN OUT GHCB                *Ghcb,
+  IN     UINT64              ExitCode,
+  IN     UINT64              ExitInfo1,
+  IN     UINT64              ExitInfo2
+  )
+{
+  GHCB_EVENT_INJECTION  Event;
+
+  Event.Uint64 = 0;
+  Event.Elements.Vector = GP_EXCEPTION;
+  Event.Elements.Type   = GHCB_EVENT_INJECTION_TYPE_EXCEPTION;
+  Event.Elements.Valid  = 1;
+
+  return Event.Uint64;
+}
+
+/**
+  Perform pre-VMGEXIT initialization/preparation.
+
+  Performs the necessary steps in preparation for invoking VMGEXIT. Must be
+  called before setting any fields within the GHCB.
+
+  The base library function does nothing.
+
+  @param[in, out]  Ghcb       A pointer to the GHCB
+
+**/
+VOID
+EFIAPI
+VmgInit (
+  IN OUT GHCB                *Ghcb
+  )
+{
+}
+
+/**
+  Perform post-VMGEXIT cleanup.
+
+  Performs the necessary steps to cleanup after invoking VMGEXIT. Must be
+  called after obtaining needed fields within the GHCB.
+
+  The base library function does nothing.
+
+  @param[in, out]  Ghcb       A pointer to the GHCB
+
+**/
+VOID
+EFIAPI
+VmgDone (
+  IN OUT GHCB                *Ghcb
+  )
+{
+}
+
+/**
+  Handle a #VC exception.
+
+  Performs the necessary processing to handle a #VC exception.
+
+  The base library function returns an error equal to VC_EXCEPTION,
+  to be propagated to the standard exception handling stack.
+
+  @param[in, out]  ExceptionType  Pointer to an EFI_EXCEPTION_TYPE to be set
+                                  as value to use on error.
+  @param[in, out]  SystemContext  Pointer to EFI_SYSTEM_CONTEXT
+
+  @retval  EFI_SUCCESS            Exception handled
+  @retval  EFI_UNSUPPORTED        #VC not supported, (new) exception value to
+                                  propagate provided
+  @retval  EFI_PROTOCOL_ERROR     #VC handling failed, (new) exception value to
+                                  propagate provided
+
+**/
+EFI_STATUS
+EFIAPI
+VmgExitHandleVc (
+  IN OUT EFI_EXCEPTION_TYPE  *ExceptionType,
+  IN OUT EFI_SYSTEM_CONTEXT  SystemContext
+  )
+{
+  *ExceptionType = VC_EXCEPTION;
+
+  return EFI_UNSUPPORTED;
+}