diff --git a/MdeModulePkg/Core/PiSmmCore/Smi.c b/MdeModulePkg/Core/PiSmmCore/Smi.c
index 3489c130fd..b3a81ac877 100644
--- a/MdeModulePkg/Core/PiSmmCore/Smi.c
+++ b/MdeModulePkg/Core/PiSmmCore/Smi.c
@@ -8,7 +8,8 @@
 
 #include "PiSmmCore.h"
 
-LIST_ENTRY  mSmiEntryList = INITIALIZE_LIST_HEAD_VARIABLE (mSmiEntryList);
+SMI_HANDLER  *mCurrentSmiHandler = NULL;
+LIST_ENTRY   mSmiEntryList       = INITIALIZE_LIST_HEAD_VARIABLE (mSmiEntryList);
 
 SMI_ENTRY  mRootSmiEntry = {
   SMI_ENTRY_SIGNATURE,
@@ -142,13 +143,18 @@ SmiManage (
     // Link points to may be freed if unregister SMI handler.
     //
     Link = Link->ForwardLink;
-
-    Status = SmiHandler->Handler (
-                           (EFI_HANDLE)SmiHandler,
-                           Context,
-                           CommBuffer,
-                           CommBufferSize
-                           );
+    //
+    // Assign gCurrentSmiHandle before calling the SMI handler and
+    // set to NULL when it returns.
+    //
+    mCurrentSmiHandler = SmiHandler;
+    Status             = SmiHandler->Handler (
+                                       (EFI_HANDLE)SmiHandler,
+                                       Context,
+                                       CommBuffer,
+                                       CommBufferSize
+                                       );
+    mCurrentSmiHandler = NULL;
 
     switch (Status) {
       case EFI_INTERRUPT_PENDING:
@@ -328,6 +334,13 @@ SmiHandlerUnRegister (
     return EFI_INVALID_PARAMETER;
   }
 
+  //
+  // Do not allow to unregister SMI Handler inside other SMI Handler
+  //
+  if ((mCurrentSmiHandler != NULL) && (mCurrentSmiHandler != SmiHandler)) {
+    return EFI_INVALID_PARAMETER;
+  }
+
   SmiEntry = SmiHandler->SmiEntry;
 
   RemoveEntryList (&SmiHandler->Link);