OvmfPkg: Extend VmgExitLib to handle #VE exception

RFC： https://bugzilla.tianocore.org/show_bug.cgi?id=3429

The base VmgExitLib library provides a default limited interface to
handle #VE exception. To provide full support, the OVMF version of
VmgExitLib is extended to provide full support of #VE handler.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>

OvmfPkg/Library/VmgExitLib/VmTdExitHandler.h

@@ -0,0 +1,32 @@
+/** @file
+
+  Copyright (c) 2020 - 2021, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef VMTD_EXIT_HANDLER_H_
+#define VMTD_EXIT_HANDLER_H_
+
+#include <Base.h>
+#include <Uefi.h>
+
+/**
+  This function enable the TD guest to request the VMM to emulate CPUID
+  operation, especially for non-architectural, CPUID leaves.
+
+  @param[in]  Eax        Main leaf of the CPUID
+  @param[in]  Ecx        Sub-leaf of the CPUID
+  @param[out] Results    Returned result of CPUID operation
+
+  @return EFI_SUCCESS
+**/
+EFI_STATUS
+EFIAPI
+TdVmCallCpuid (
+  IN UINT64  Eax,
+  IN UINT64  Ecx,
+  OUT VOID   *Results
+  );
+
+#endif