UefiCpuPkg/MtrrLib: Avoid running unnecessary code

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>

diff --git a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
index c38191a7efc15a9bab859381e7817d0b4e64141c..9d1927262a4edee650bd18621fac69cba7f73738 100644 (file)
--- a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
+++ b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
@@ -1536,6 +1536,7 @@ MtrrLibAddVariableMtrr (
 \r
   MTRR_LIB_ASSERT_ALIGNED (BaseAddress, Length);\r
   if (Type == CacheInvalid) {\r
 \r
   MTRR_LIB_ASSERT_ALIGNED (BaseAddress, Length);\r
   if (Type == CacheInvalid) {\r

+    ASSERT (Ranges != NULL);\r

     for (Index = 0; Index < RangeCount; Index++) {\r
       if (Ranges[Index].BaseAddress <= BaseAddress && BaseAddress < Ranges[Index].BaseAddress + Ranges[Index].Length) {\r
 \r
     for (Index = 0; Index < RangeCount; Index++) {\r
       if (Ranges[Index].BaseAddress <= BaseAddress && BaseAddress < Ranges[Index].BaseAddress + Ranges[Index].Length) {\r
 \r


@@ -2027,25 +2028,27 @@ MtrrSetMemoryAttributeWorker (
   ASSERT (OriginalVariableMtrrCount - FreeVariableMtrrCount <= FirmwareVariableMtrrCount);\r
 \r
   //\r
   ASSERT (OriginalVariableMtrrCount - FreeVariableMtrrCount <= FirmwareVariableMtrrCount);\r
 \r
   //\r

-  // Move MTRRs after the FirmwraeVariableMtrrCount position to beginning\r
+  // Move MTRRs after the FirmwareVariableMtrrCount position to beginning\r

   //\r
   //\r

-  WorkingIndex = FirmwareVariableMtrrCount;\r
-  for (Index = 0; Index < FirmwareVariableMtrrCount; Index++) {\r
-    if (!OriginalVariableMtrr[Index].Valid) {\r
-      //\r
-      // Found an empty MTRR in WorkingIndex position\r
-      //\r
-      for (; WorkingIndex < OriginalVariableMtrrCount; WorkingIndex++) {\r
-        if (OriginalVariableMtrr[WorkingIndex].Valid) {\r
-          break;\r
+  if (FirmwareVariableMtrrCount < OriginalVariableMtrrCount) {\r
+    WorkingIndex = FirmwareVariableMtrrCount;\r
+    for (Index = 0; Index < FirmwareVariableMtrrCount; Index++) {\r
+      if (!OriginalVariableMtrr[Index].Valid) {\r
+        //\r
+        // Found an empty MTRR in WorkingIndex position\r
+        //\r
+        for (; WorkingIndex < OriginalVariableMtrrCount; WorkingIndex++) {\r
+          if (OriginalVariableMtrr[WorkingIndex].Valid) {\r
+            break;\r
+          }\r

         }\r
         }\r

-      }\r

 \r
 \r

-      if (WorkingIndex != OriginalVariableMtrrCount) {\r
-        CopyMem (&OriginalVariableMtrr[Index], &OriginalVariableMtrr[WorkingIndex], sizeof (VARIABLE_MTRR));\r
-        VariableSettingModified[Index] = TRUE;\r
-        VariableSettingModified[WorkingIndex] = TRUE;\r
-        OriginalVariableMtrr[WorkingIndex].Valid = FALSE;\r
+        if (WorkingIndex != OriginalVariableMtrrCount) {\r
+          CopyMem (&OriginalVariableMtrr[Index], &OriginalVariableMtrr[WorkingIndex], sizeof (VARIABLE_MTRR));\r
+          VariableSettingModified[Index] = TRUE;\r
+          VariableSettingModified[WorkingIndex] = TRUE;\r
+          OriginalVariableMtrr[WorkingIndex].Valid = FALSE;\r
+        }\r

       }\r
     }\r
   }\r
       }\r
     }\r
   }\r