From 947a573ada499a7b1533d91f015327cc07605ff7 Mon Sep 17 00:00:00 2001
From: xli24 <xli24@6f19259b-4bc3-4df7-8a09-765794883524>
Date: Wed, 10 Mar 2010 02:38:39 +0000
Subject: Add Checking for MTRR existence.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@10223 6f19259b-4bc3-4df7-8a09-765794883524
---
 UefiCpuPkg/CpuDxe/CpuDxe.c           |  8 ++++
 UefiCpuPkg/Include/Library/MtrrLib.h | 12 +++++
 UefiCpuPkg/Library/MtrrLib/MtrrLib.c | 89 +++++++++++++++++++++++++++++++++++-
 3 files changed, 108 insertions(+), 1 deletion(-)

(limited to 'UefiCpuPkg')

diff --git a/UefiCpuPkg/CpuDxe/CpuDxe.c b/UefiCpuPkg/CpuDxe/CpuDxe.c
index 457823d5cd..e3b21d8463 100644
--- a/UefiCpuPkg/CpuDxe/CpuDxe.c
+++ b/UefiCpuPkg/CpuDxe/CpuDxe.c
@@ -590,6 +590,10 @@ CpuSetMemoryAttributes (
   RETURN_STATUS             Status;
   MTRR_MEMORY_CACHE_TYPE    CacheType;
 
+  if (!IsMtrrSupported ()) {
+    return EFI_UNSUPPORTED;
+  }
+
   DEBUG((EFI_D_ERROR, "CpuAp: SetMemorySpaceAttributes(BA=%08x, Len=%08x, Attr=%08x)\n", BaseAddress, Length, Attributes));
 
   //
@@ -856,6 +860,10 @@ RefreshGcdMemoryAttributes (
   MTRR_FIXED_SETTINGS                 MtrrFixedSettings;
   UINT32                              FirmwareVariableMtrrCount;
 
+  if (!IsMtrrSupported ()) {
+    return;
+  }
+
   FirmwareVariableMtrrCount = GetFirmwareVariableMtrrCount ();
   ASSERT (FirmwareVariableMtrrCount <= MTRR_NUMBER_OF_VARIABLE_MTRR);
 
diff --git a/UefiCpuPkg/Include/Library/MtrrLib.h b/UefiCpuPkg/Include/Library/MtrrLib.h
index e2f2491eee..66e131d4fd 100644
--- a/UefiCpuPkg/Include/Library/MtrrLib.h
+++ b/UefiCpuPkg/Include/Library/MtrrLib.h
@@ -314,4 +314,16 @@ VOID
 MtrrDebugPrintAllMtrrs (
   );
 
+/**
+  Checks if MTRR is supported.
+
+  @retval TRUE  MTRR is supported.
+  @retval FALSE MTRR is not supported.
+
+**/
+BOOLEAN
+IsMtrrSupported (
+  VOID
+  );
+
 #endif // _MTRR_LIB_H_
diff --git a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
index 4e6878f282..dab0535fe9 100644
--- a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
+++ b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
@@ -93,6 +93,10 @@ GetVariableMtrrCount (
   VOID
   )
 {
+  if (!IsMtrrSupported ()) {
+    return 0;
+  }
+
   return (UINT32)(AsmReadMsr64 (MTRR_LIB_IA32_MTRR_CAP) & MTRR_LIB_IA32_MTRR_CAP_VCNT_MASK);
 }
 
@@ -107,7 +111,14 @@ GetFirmwareVariableMtrrCount (
   VOID
   )
 {
-  return GetVariableMtrrCount () - RESERVED_FIRMWARE_VARIABLE_MTRR_NUMBER;
+  UINT32  VariableMtrrCount;
+
+  VariableMtrrCount = GetVariableMtrrCount ();
+  if (VariableMtrrCount < RESERVED_FIRMWARE_VARIABLE_MTRR_NUMBER) {
+    return 0;
+  }
+
+  return VariableMtrrCount - RESERVED_FIRMWARE_VARIABLE_MTRR_NUMBER;
 }
 
 /**
@@ -319,6 +330,10 @@ MtrrGetMemoryAttributeInVariableMtrr (
   UINT32  FirmwareVariableMtrrCount;
   UINT32  VariableMtrrEnd;
 
+  if (!IsMtrrSupported ()) {
+    return 0;
+  }
+
   FirmwareVariableMtrrCount = GetFirmwareVariableMtrrCount ();
   VariableMtrrEnd = MTRR_LIB_IA32_VARIABLE_MTRR_BASE + (2 * GetVariableMtrrCount ()) - 1;
 
@@ -870,6 +885,10 @@ MtrrSetMemoryAttribute (
   UINT32                    FirmwareVariableMtrrCount;
   UINT32                    VariableMtrrEnd;
 
+  if (!IsMtrrSupported ()) {
+    return RETURN_UNSUPPORTED;
+  }
+
   FirmwareVariableMtrrCount = GetFirmwareVariableMtrrCount ();
   VariableMtrrEnd = MTRR_LIB_IA32_VARIABLE_MTRR_BASE + (2 * GetVariableMtrrCount ()) - 1;
 
@@ -1110,6 +1129,10 @@ MtrrGetMemoryAttribute (
   UINT64                  MtrrValidAddressMask;
   UINTN                   VariableMtrrCount;
 
+  if (!IsMtrrSupported ()) {
+    return CacheUncacheable;
+  }
+
   //
   // Check if MTRR is enabled, if not, return UC as attribute
   //
@@ -1190,6 +1213,10 @@ MtrrGetVariableMtrr (
   UINT32  Index;
   UINT32  VariableMtrrCount;
 
+  if (!IsMtrrSupported ()) {
+    return VariableSettings;
+  }
+
   VariableMtrrCount = GetVariableMtrrCount ();
   ASSERT (VariableMtrrCount <= MTRR_NUMBER_OF_VARIABLE_MTRR);
 
@@ -1250,6 +1277,10 @@ MtrrSetVariableMtrr (
 {
   UINTN  Cr4;
 
+  if (!IsMtrrSupported ()) {
+    return VariableSettings;
+  }
+
   Cr4 = PreMtrrChange ();
   MtrrSetVariableMtrrWorker (VariableSettings);
   PostMtrrChange (Cr4);
@@ -1273,6 +1304,10 @@ MtrrGetFixedMtrr (
 {
   UINT32  Index;
 
+  if (!IsMtrrSupported ()) {
+    return FixedSettings;
+  }
+
   for (Index = 0; Index < MTRR_NUMBER_OF_FIXED_MTRR; Index++) {
       FixedSettings->Mtrr[Index] =
         AsmReadMsr64 (MtrrLibFixedMtrrTable[Index].Msr);
@@ -1319,6 +1354,10 @@ MtrrSetFixedMtrr (
 {
   UINTN  Cr4;
 
+  if (!IsMtrrSupported ()) {
+    return FixedSettings;
+  }
+
   Cr4 = PreMtrrChange ();
   MtrrSetFixedMtrrWorker (FixedSettings);
   PostMtrrChange (Cr4);
@@ -1341,6 +1380,10 @@ MtrrGetAllMtrrs (
   OUT MTRR_SETTINGS                *MtrrSetting
   )
 {
+  if (!IsMtrrSupported ()) {
+    return MtrrSetting;
+  }
+
   //
   // Get fixed MTRRs
   //
@@ -1376,6 +1419,10 @@ MtrrSetAllMtrrs (
 {
   UINTN  Cr4;
 
+  if (!IsMtrrSupported ()) {
+    return MtrrSetting;
+  }
+
   Cr4 = PreMtrrChange ();
 
   //
@@ -1412,6 +1459,10 @@ MtrrDebugPrintAllMtrrs (
       UINTN          Index;
       UINTN          VariableMtrrCount;
 
+      if (!IsMtrrSupported ()) {
+        return;
+      }
+
       MtrrGetAllMtrrs (&MtrrSettings);
       DEBUG((EFI_D_ERROR, "DefaultType = %016lx\n", MtrrSettings.MtrrDefType));
       for (Index = 0; Index < MTRR_NUMBER_OF_FIXED_MTRR; Index++) {
@@ -1435,3 +1486,39 @@ MtrrDebugPrintAllMtrrs (
   );
 }
 
+/**
+  Checks if MTRR is supported.
+
+  @retval TRUE  MTRR is supported.
+  @retval FALSE MTRR is not supported.
+
+**/
+BOOLEAN
+EFIAPI
+IsMtrrSupported (
+  VOID
+  )
+{
+  UINT32  RegEdx;
+  UINT64  MtrrCap;
+
+  //
+  // Check CPUID(1).EDX[12] for MTRR capability
+  //
+  AsmCpuid (1, NULL, NULL, NULL, &RegEdx);
+  if (BitFieldRead32 (RegEdx, 12, 12) == 0) {
+    return FALSE;
+  }
+
+  //
+  // Check IA32_MTRRCAP.[0..7] for number of variable MTRRs and IA32_MTRRCAP[8] for
+  // fixed MTRRs existence. If number of variable MTRRs is zero, or fixed MTRRs do not
+  // exist, return false.
+  //
+  MtrrCap = AsmReadMsr64 (MTRR_LIB_IA32_MTRR_CAP);
+  if  ((BitFieldRead64 (MtrrCap, 0, 7) == 0) || (BitFieldRead64 (MtrrCap, 8, 8) == 0)) {
+    return FALSE;
+  }
+
+  return TRUE;
+}
-- 
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