diff --git a/UefiCpuPkg/CpuDxe/CpuPageTable.c b/UefiCpuPkg/CpuDxe/CpuPageTable.c
index 850eed60e7..df021798c0 100644
--- a/UefiCpuPkg/CpuDxe/CpuPageTable.c
+++ b/UefiCpuPkg/CpuDxe/CpuPageTable.c
@@ -136,7 +136,14 @@ IsInSmm (
     mSmmBase2->InSmm (mSmmBase2, &InSmm);
   }
 
-  return InSmm;
+  //
+  // mSmmBase2->InSmm() can only detect if the caller is running in SMRAM
+  // or from SMM driver. It cannot tell if the caller is running in SMM mode.
+  // Check page table base address to guarantee that because SMM mode willl
+  // load its own page table.
+  //
+  return (InSmm &&
+          mPagingContext.ContextData.X64.PageTableBase != (UINT64)AsmReadCr3());
 }
 
 /**