UefiCpuPkg/AmdSvsmLib: Create the AmdSvsmLib library to support an SVSM

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4654

In order to support an SEV-SNP guest running under an SVSM at VMPL1 or
lower, a new library must be created.

This library includes an interface to detect if running under an SVSM, an
interface to return the current VMPL, an interface to perform memory
validation and an interface to set or clear the attribute that allows a
page to be used as a VMSA.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Acked-by: Ray Ni <ray.ni@intel.com>

UefiCpuPkg/Library/AmdSvsmLibNull/AmdSvsmLibNull.uni

@@ -0,0 +1,13 @@
+// /** @file
+// AmdSvsmLib instance.
+//
+// Copyright (C) 2024, Advanced Micro Devices, Inc. All rights reserved.<BR>
+// SPDX-License-Identifier: BSD-2-Clause-Patent
+//
+// **/
+
+
+#string STR_MODULE_ABSTRACT             #language en-US "AmdSvsmLib NULL instance"
+
+#string STR_MODULE_DESCRIPTION          #language en-US "AmdSvsmLib NULL instance."
+