UefiCpuPkg/CommonFeature: Skip locking when the feature is disabled

[mirror_edk2.git] / UefiCpuPkg / Library / CpuCommonFeaturesLib / FeatureControl.c

diff --git a/UefiCpuPkg/Library/CpuCommonFeaturesLib/FeatureControl.c b/UefiCpuPkg/Library/CpuCommonFeaturesLib/FeatureControl.c
index 8c1eb5eb4f80a1996b177a8b2ee4d559a8598d23..631c83685706cd00d8eb9451906206dc33ba478d 100644 (file)
--- a/UefiCpuPkg/Library/CpuCommonFeaturesLib/FeatureControl.c
+++ b/UefiCpuPkg/Library/CpuCommonFeaturesLib/FeatureControl.c
@@ -1,7 +1,7 @@
 /** @file\r
   Features in MSR_IA32_FEATURE_CONTROL register.\r
 \r
-  Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>\r
+  Copyright (c) 2017 - 2018, Intel Corporation. All rights reserved.<BR>\r
   This program and the accompanying materials\r
   are licensed and made available under the terms and conditions of the BSD License\r
   which accompanies this distribution.  The full text of the license may be found at\r
@@ -184,6 +184,15 @@ LockFeatureControlRegisterInitialize (
 {\r
   MSR_IA32_FEATURE_CONTROL_REGISTER    *MsrRegister;\r
 \r
+  //\r
+  // When Lock Feature Control Register feature is disabled,\r
+  // just skip the MSR lock bit setting.\r
+  // The MSR lock bit is cleared by default and write-once in a boot.\r
+  //\r
+  if (!State) {\r
+    return RETURN_SUCCESS;\r
+  }\r
+\r
   //\r
   // The scope of Lock bit in the MSR_IA32_FEATURE_CONTROL is core for\r
   // below processor type, only program MSR_IA32_FEATURE_CONTROL for thread 0 in each\r