UefiCpuPkg/MtrrLib: Fix bug that may incorrectly set <1MB attribute

[mirror_edk2.git] / UefiCpuPkg / Library / MtrrLib / MtrrLib.c

diff --git a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
index cb22558103cd5db28b69c31ffa18ec287c5a6f04..200becdd4a2500eb3145788bc2f97a19a47c3aae 100644 (file)
--- a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
+++ b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
@@ -2114,22 +2114,32 @@ MtrrLibSetBelow1MBMemoryAttribute (
   UINT64                    OrMask;\r
   UINT64                    ClearMasks[ARRAY_SIZE (mMtrrLibFixedMtrrTable)];\r
   UINT64                    OrMasks[ARRAY_SIZE (mMtrrLibFixedMtrrTable)];\r
+  BOOLEAN                   LocalModified[ARRAY_SIZE (mMtrrLibFixedMtrrTable)];\r
 \r
   ASSERT (BaseAddress < BASE_1MB);\r
 \r
+  SetMem (LocalModified, sizeof (LocalModified), FALSE);\r
+\r
+  //\r
+  // (Value & ~0 | 0) still equals to (Value)\r
+  //\r
+  SetMem64 (ClearMasks, sizeof (ClearMasks), 0);\r
+  SetMem64 (OrMasks, sizeof (OrMasks), 0);\r
+\r
   MsrIndex = (UINT32)-1;\r
   while ((BaseAddress < BASE_1MB) && (Length != 0)) {\r
     Status = MtrrLibProgramFixedMtrr (Type, &BaseAddress, &Length, &MsrIndex, &ClearMask, &OrMask);\r
     if (RETURN_ERROR (Status)) {\r
       return Status;\r
     }\r
-    ClearMasks[MsrIndex] = ClearMask;\r
-    OrMasks[MsrIndex]    = OrMask;\r
-    Modified[MsrIndex]   = TRUE;\r
+    ClearMasks[MsrIndex]    = ClearMask;\r
+    OrMasks[MsrIndex]       = OrMask;\r
+    Modified[MsrIndex]      = TRUE;\r
+    LocalModified[MsrIndex] = TRUE;\r
   }\r
 \r
   for (MsrIndex = 0; MsrIndex < ARRAY_SIZE (mMtrrLibFixedMtrrTable); MsrIndex++) {\r
-    if (Modified[MsrIndex]) {\r
+    if (LocalModified[MsrIndex]) {\r
       FixedSettings->Mtrr[MsrIndex] = (FixedSettings->Mtrr[MsrIndex] & ~ClearMasks[MsrIndex]) | OrMasks[MsrIndex];\r
     }\r
   }\r
@@ -2354,6 +2364,7 @@ MtrrSetMemoryAttributesInMtrrSettings (
   //\r
   // 3. Apply the below-1MB memory attribute settings.\r
   //\r
+  ZeroMem (WorkingFixedSettings.Mtrr, sizeof (WorkingFixedSettings.Mtrr));\r
   for (Index = 0; Index < RangeCount; Index++) {\r
     if (Ranges[Index].BaseAddress >= BASE_1MB) {\r
       continue;\r