1 files changed, 5 insertions, 0 deletions
diff --git a/UefiCpuPkg/Include/Library/RegisterCpuFeaturesLib.h b/UefiCpuPkg/Include/Library/RegisterCpuFeaturesLib.h
index 9331e49d13..fc3ccda1ba 100644
--- a/UefiCpuPkg/Include/Library/RegisterCpuFeaturesLib.h
+++ b/UefiCpuPkg/Include/Library/RegisterCpuFeaturesLib.h
@@ -71,6 +71,11 @@
 #define CPU_FEATURE_APIC_TPR_UPDATE_MESSAGE         (32+9)
 #define CPU_FEATURE_ENERGY_PERFORMANCE_BIAS         (32+10)
 #define CPU_FEATURE_PPIN                            (32+11)
+//
+// Currently, CPU_FEATURE_PROC_TRACE is the MAX feature we support.
+// If you define a feature bigger than it, please also replace it
+// in RegisterCpuFeatureLibIsFeatureValid function.
+//
 #define CPU_FEATURE_PROC_TRACE                      (32+12)
 
 #define CPU_FEATURE_BEFORE_ALL                      BIT27