From 46fd118219fcce638f1eb9c861f4a037530b64b9 Mon Sep 17 00:00:00 2001
From: Jeff Fan <jeff.fan@intel.com>
Date: Fri, 1 Jul 2016 14:51:10 +0800
Subject: [PATCH] UefiCpuPkg/CpuMpPei: Skip microcode check/load if it has been
 loaded

Actually, there is only one microcode region in platform. If microcode has been
loaded, its signature will not be zero and should be loaded successfully.
We needn't to check microcode region and load microcode again. This update is to
skip checking/loading microcode if current microcode signature is not zero.

Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Cc: Giri P Mudusuru <giri.p.mudusuru@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Giri P Mudusuru <giri.p.mudusuru@intel.com>
---
 UefiCpuPkg/CpuMpPei/Microcode.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/UefiCpuPkg/CpuMpPei/Microcode.c b/UefiCpuPkg/CpuMpPei/Microcode.c
index 3fd3a8bb81..67280d334d 100644
--- a/UefiCpuPkg/CpuMpPei/Microcode.c
+++ b/UefiCpuPkg/CpuMpPei/Microcode.c
@@ -53,6 +53,7 @@ MicrocodeDetect (
   UINTN                                   Index;
   UINT8                                   PlatformId;
   UINT32                                  RegEax;
+  UINT32                                  CurrentRevision;
   UINT32                                  LatestRevision;
   UINTN                                   TotalSize;
   UINT32                                  CheckSum32;
@@ -69,6 +70,14 @@ MicrocodeDetect (
     return;
   }
 
+  CurrentRevision = GetCurrentMicrocodeSignature ();
+  if (CurrentRevision != 0) {
+    //
+    // Skip loading microcode if it has been loaded successfully
+    //
+    return;
+  }
+
   ExtendedTableLength = 0;
   //
   // Here data of CPUID leafs have not been collected into context buffer, so