Intel plans to separate the smbase relocation logic from
PiSmmCpuDxeSmm driver, and the related behavior will be
moved to the new interface defined by the SmmRelocationLib
class.

The SmmRelocationLib class provides the SmmRelocationInit()
interface for platform to do the smbase relocation, which
shall provide below 2 functionalities:
1. Relocate smbases for each processor.
2. Create the gSmmBaseHobGuid HOB.

With SmmRelocationLib, PiSmmCpuDxeSmm driver (which runs at
a later phase) shall:
1. Consume the gSmmBaseHobGuid HOB for the relocated smbases
for each Processor.
2. Execute the early SMM Init.

This patch just provides the SmmRelocationLib class.

Cc: Ray Ni <ray.ni@intel.com>
Cc: Zeng Star <star.zeng@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
---
 UefiCpuPkg/Include/Library/SmmRelocationLib.h | 42 +++++++++++++++++++++++++++
 UefiCpuPkg/UefiCpuPkg.dec                     |  3 ++
 2 files changed, 45 insertions(+)
 create mode 100644 UefiCpuPkg/Include/Library/SmmRelocationLib.h

diff --git a/UefiCpuPkg/Include/Library/SmmRelocationLib.h b/UefiCpuPkg/Include/Library/SmmRelocationLib.h
new file mode 100644
index 0000000000..999a5b46d1
--- /dev/null
+++ b/UefiCpuPkg/Include/Library/SmmRelocationLib.h
@@ -0,0 +1,42 @@
+/** @file
+  Header file for SMM Relocation Library.
+
+  The SmmRelocationLib class provides the SmmRelocationInit()
+  interface for platform to do the smbase relocation, which
+  shall provide below 2 functionalities:
+  1. Relocate SmBases for each processor.
+  2. Create the SmBase HOB (gSmmBaseHobGuid).
+
+  With SmmRelocationLib, PiSmmCpuDxeSmm driver (which runs at a later phase)
+  shall:
+  1. Consume the gSmmBaseHobGuid for the relocated smbase for each Processor.
+  2. Execute early SMM init.
+
+  Copyright (c) 2024, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef SMM_RELOCATION_LIB_H_
+#define SMM_RELOCATION_LIB_H_
+
+#include <Ppi/MpServices2.h>
+
+/**
+  CPU SmmBase Relocation Init.
+
+  This function is to relocate CPU SmmBase.
+
+  @param[in] MpServices2        Pointer to this instance of the MpServices.
+
+  @retval EFI_SUCCESS           CPU SmmBase Relocated successfully.
+  @retval Others                CPU SmmBase Relocation failed.
+
+**/
+EFI_STATUS
+EFIAPI
+SmmRelocationInit (
+  IN EDKII_PEI_MP_SERVICES2_PPI  *MpServices2
+  );
+
+#endif
diff --git a/UefiCpuPkg/UefiCpuPkg.dec b/UefiCpuPkg/UefiCpuPkg.dec
index 571b59b36f..1d7890f19e 100644
--- a/UefiCpuPkg/UefiCpuPkg.dec
+++ b/UefiCpuPkg/UefiCpuPkg.dec
@@ -65,10 +65,13 @@
   MmSaveStateLib|Include/Library/MmSaveStateLib.h
 
   ## @libraryclass   Provides functions for SMM CPU Sync Operation.
   SmmCpuSyncLib|Include/Library/SmmCpuSyncLib.h
 
+  ## @libraryclass   Provides functions for SMM Relocation Operation.
+  SmmRelocationLib|Include/Library/SmmRelocationLib.h
+
 [LibraryClasses.RISCV64]
   ##  @libraryclass  Provides functions to manage MMU features on RISCV64 CPUs.
   ##
   RiscVMmuLib|Include/Library/BaseRiscVMmuLib.h
 
--
2.16.2.windows.1