From 3c79bd38e0d034170a4c7d6c6f01c48c704fdfe4 Mon Sep 17 00:00:00 2001
From: Michael D Kinney <michael.d.kinney@intel.com>
Date: Mon, 21 Apr 2025 17:35:21 -0700
Subject: [PATCH] UefiCpuPkg: Add back gEdkiiPeiMpServices2PpiGuid

Commit aef50446ced0662c8dfd968ab0ea05cc88b989ae
removed gEdkiiPeiMpServices2PpiGuid from UefiCpuPkg.dec
which causes build breaks if an INF [Ppis] section
lists gEdkiiPeiMpServices2PpiGuid. There is no method
for a DEC file for conditionally declare a PPI.

In order to support the migration from use of
gEdkiiPeiMpServices2PpiGuid to the preferred use of the
gPeiMpServices2Ppi, add gEdkiiPeiMpServices2PpiGuid back
to the UefiCpuPkg.dec.

All references to the EDK II PEI MP Services 2 PPI can be
removed after all downstream consumers have had a chance
to perform the migration.

Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
---
 UefiCpuPkg/UefiCpuPkg.ci.yaml | 2 +-
 UefiCpuPkg/UefiCpuPkg.dec     | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/UefiCpuPkg/UefiCpuPkg.ci.yaml b/UefiCpuPkg/UefiCpuPkg.ci.yaml
index 80a043f339..a6fd1471de 100644
--- a/UefiCpuPkg/UefiCpuPkg.ci.yaml
+++ b/UefiCpuPkg/UefiCpuPkg.ci.yaml
@@ -74,7 +74,7 @@
         "IgnoreGuidName": ["SecCore", "ResetVector"], # Expected duplication for gEfiFirmwareVolumeTopFileGuid
         "IgnoreGuidValue": [],
         "IgnoreFoldersAndFiles": [],
-        "IgnoreDuplicates": []
+        "IgnoreDuplicates": ["gEdkiiPeiMpServices2PpiGuid=gEfiPeiMpServices2PpiGuid"]
     },
     "LibraryClassCheck": {
         "IgnoreHeaderFile": []
diff --git a/UefiCpuPkg/UefiCpuPkg.dec b/UefiCpuPkg/UefiCpuPkg.dec
index 892ff95ad4..9a8471ed44 100644
--- a/UefiCpuPkg/UefiCpuPkg.dec
+++ b/UefiCpuPkg/UefiCpuPkg.dec
@@ -148,6 +148,13 @@
 #
 
 [Ppis]
+  #
+  # The EDK II PEI MP Services 2 PPI has been replaced by the PEI MP Services 2 PPI
+  # in the MdePkg. The following definition is only present for backwards compatibility
+  # and will be removed in the future.
+  #
+  gEdkiiPeiMpServices2PpiGuid =    { 0x5cb9cb3d, 0x31a4, 0x480c, { 0x94, 0x98, 0x29, 0xd2, 0x69, 0xba, 0xcf, 0xba}}
+
   ## Include/Ppi/ShadowMicrocode.h
   gEdkiiPeiShadowMicrocodePpiGuid = { 0x430f6965, 0x9a69, 0x41c5, { 0x93, 0xed, 0x8b, 0xf0, 0x64, 0x35, 0xc1, 0xc6 }}