4 files changed, 49 insertions, 8 deletions
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/PageTbl.c b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/PageTbl.c
index 05fb455..f891a81 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/PageTbl.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/PageTbl.c
@@ -336,3 +336,17 @@ RestoreCr2 (
 {
   return ;
 }
+
+/**
+  Return whether access to non-SMRAM is restricted.
+
+  @retval TRUE  Access to non-SMRAM is restricted.
+  @retval FALSE Access to non-SMRAM is not restricted.
+*/
+BOOLEAN
+IsRestrictedMemoryAccess (
+  VOID
+  )
+{
+  return TRUE;
+}
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c
index 69a04df..723fd50 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c
@@ -1431,15 +1431,17 @@ PerformRemainingTasks (
     //
     SetMemMapAttributes ();
 
-    //
-    // For outside SMRAM, we only map SMM communication buffer or MMIO.
-    //
-    SetUefiMemMapAttributes ();
+    if (IsRestrictedMemoryAccess ()) {
+      //
+      // For outside SMRAM, we only map SMM communication buffer or MMIO.
+      //
+      SetUefiMemMapAttributes ();
 
-    //
-    // Set page table itself to be read-only
-    //
-    SetPageTableAttributes ();
+      //
+      // Set page table itself to be read-only
+      //
+      SetPageTableAttributes ();
+    }
 
     //
     // Configure SMM Code Access Check feature if available.
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h
index 8c29f1a..daf977f 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h
@@ -1450,4 +1450,15 @@ InitializeDataForMmMp (
   VOID
   );
 
+/**
+  Return whether access to non-SMRAM is restricted.
+
+  @retval TRUE  Access to non-SMRAM is restricted.
+  @retval FALSE Access to non-SMRAM is not restricted.
+*/
+BOOLEAN
+IsRestrictedMemoryAccess (
+  VOID
+  );
+
 #endif
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
index 7516f35..733d107 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
@@ -1252,3 +1252,17 @@ RestoreCr2 (
     AsmWriteCr2 (Cr2);
   }
 }
+
+/**
+  Return whether access to non-SMRAM is restricted.
+
+  @retval TRUE  Access to non-SMRAM is restricted.
+  @retval FALSE Access to non-SMRAM is not restricted.
+*/
+BOOLEAN
+IsRestrictedMemoryAccess (
+  VOID
+  )
+{
+  return mCpuSmmRestrictedMemoryAccess;
+}