7 files changed, 38 insertions, 32 deletions
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/PrivilegePolymorphic.h b/MdeModulePkg/Universal/Variable/RuntimeDxe/PrivilegePolymorphic.h
index a324ad2365..7af22a4ad6 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/PrivilegePolymorphic.h
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/PrivilegePolymorphic.h
@@ -85,13 +85,15 @@ SetVariableCheckHandlerMor (
   );
 
 /**
-  This service is consumed by the variable modules to perform a serializing
-  operation on all load-from-memory instructions that were issued prior to the
-  call of this function.
+  This service is consumed by the variable modules to place a barrier to stop
+  speculative execution.
+
+  Ensures that no later instruction will execute speculatively, until all prior
+  instructions have completed.
 
 **/
 VOID
-MemoryLoadFence (
+VariableSpeculationBarrier (
   VOID
   );
 
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/LoadFenceDxe.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/SpeculationBarrierDxe.c
index 0f64ee093b..bc3f695335 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/LoadFenceDxe.c
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/SpeculationBarrierDxe.c
@@ -1,5 +1,5 @@
 /** @file
-  Serialize operation on all load-from-memory instructions (DXE version).
+  Barrier to stop speculative execution (DXE version).
 
 Copyright (c) 2018, Intel Corporation. All rights reserved.<BR>
 This program and the accompanying materials
@@ -15,13 +15,15 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #include "Variable.h"
 
 /**
-  This service is consumed by the variable modules to perform a serializing
-  operation on all load-from-memory instructions that were issued prior to the
-  call of this function.
+  This service is consumed by the variable modules to place a barrier to stop
+  speculative execution.
+
+  Ensures that no later instruction will execute speculatively, until all prior
+  instructions have completed.
 
 **/
 VOID
-MemoryLoadFence (
+VariableSpeculationBarrier (
   VOID
   )
 {
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/LoadFenceSmm.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/SpeculationBarrierSmm.c
index 4b0d7e3e95..dbc20f6c4d 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/LoadFenceSmm.c
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/SpeculationBarrierSmm.c
@@ -1,5 +1,5 @@
 /** @file
-  Serialize operation on all load-from-memory instructions (SMM version).
+  Barrier to stop speculative execution (SMM version).
 
 Copyright (c) 2018, Intel Corporation. All rights reserved.<BR>
 This program and the accompanying materials
@@ -16,15 +16,17 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #include "Variable.h"
 
 /**
-  This service is consumed by the variable modules to perform a serializing
-  operation on all load-from-memory instructions that were issued prior to the
-  call of this function.
+  This service is consumed by the variable modules to place a barrier to stop
+  speculative execution.
+
+  Ensures that no later instruction will execute speculatively, until all prior
+  instructions have completed.
 
 **/
 VOID
-MemoryLoadFence (
+VariableSpeculationBarrier (
   VOID
   )
 {
-  AsmLfence ();
+  SpeculationBarrier ();
 }
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
index d100b1dcc5..443cf07144 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
@@ -3201,11 +3201,11 @@ VariableServiceSetVariable (
       return EFI_SECURITY_VIOLATION;
     }
     //
-    // The MemoryLoadFence() call here is to ensure the above sanity check
-    // for the EFI_VARIABLE_AUTHENTICATION_2 descriptor has been completed
+    // The VariableSpeculationBarrier() call here is to ensure the above sanity
+    // check for the EFI_VARIABLE_AUTHENTICATION_2 descriptor has been completed
     // before the execution of subsequent codes.
     //
-    MemoryLoadFence ();
+    VariableSpeculationBarrier ();
     PayloadSize = DataSize - AUTHINFO2_SIZE (Data);
   } else {
     PayloadSize = DataSize;
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
index 868981ccaf..7ef8a97f5d 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
@@ -46,7 +46,7 @@
   TcgMorLockDxe.c
   VarCheck.c
   VariableExLib.c
-  LoadFenceDxe.c
+  SpeculationBarrierDxe.c
 
 [Packages]
   MdePkg/MdePkg.dec
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
index 6dc19c24db..8c53f84ff6 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
@@ -538,11 +538,11 @@ SmmVariableHandler (
       }
 
       //
-      // The MemoryLoadFence() call here is to ensure the previous range/content
-      // checks for the CommBuffer have been completed before the subsequent
-      // consumption of the CommBuffer content.
+      // The VariableSpeculationBarrier() call here is to ensure the previous
+      // range/content checks for the CommBuffer have been completed before the
+      // subsequent consumption of the CommBuffer content.
       //
-      MemoryLoadFence ();
+      VariableSpeculationBarrier ();
       if (SmmVariableHeader->NameSize < sizeof (CHAR16) || SmmVariableHeader->Name[SmmVariableHeader->NameSize/sizeof (CHAR16) - 1] != L'\0') {
         //
         // Make sure VariableName is A Null-terminated string.
@@ -638,11 +638,11 @@ SmmVariableHandler (
       }
 
       //
-      // The MemoryLoadFence() call here is to ensure the previous range/content
-      // checks for the CommBuffer have been completed before the subsequent
-      // consumption of the CommBuffer content.
+      // The VariableSpeculationBarrier() call here is to ensure the previous
+      // range/content checks for the CommBuffer have been completed before the
+      // subsequent consumption of the CommBuffer content.
       //
-      MemoryLoadFence ();
+      VariableSpeculationBarrier ();
       if (SmmVariableHeader->NameSize < sizeof (CHAR16) || SmmVariableHeader->Name[SmmVariableHeader->NameSize/sizeof (CHAR16) - 1] != L'\0') {
         //
         // Make sure VariableName is A Null-terminated string.
@@ -779,11 +779,11 @@ SmmVariableHandler (
       }
 
       //
-      // The MemoryLoadFence() call here is to ensure the previous range/content
-      // checks for the CommBuffer have been completed before the subsequent
-      // consumption of the CommBuffer content.
+      // The VariableSpeculationBarrier() call here is to ensure the previous
+      // range/content checks for the CommBuffer have been completed before the
+      // subsequent consumption of the CommBuffer content.
       //
-      MemoryLoadFence ();
+      VariableSpeculationBarrier ();
       if (CommVariableProperty->NameSize < sizeof (CHAR16) || CommVariableProperty->Name[CommVariableProperty->NameSize/sizeof (CHAR16) - 1] != L'\0') {
         //
         // Make sure VariableName is A Null-terminated string.
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
index 2fe72ff8a4..db7d220e06 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
@@ -54,7 +54,7 @@
   PrivilegePolymorphic.h
   VariableExLib.c
   TcgMorLockSmm.c
-  LoadFenceSmm.c
+  SpeculationBarrierSmm.c
 
 [Packages]
   MdePkg/MdePkg.dec