diff --git a/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.S b/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.S
deleted file mode 100644
index 23e08f3f6e..0000000000
--- a/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.S
+++ /dev/null
@@ -1,13 +0,0 @@
-# UINT16
-# EFIAPI
-# InternalSyncCompareExchange16 (
-#   IN      volatile UINT16           *Value,
-#   IN      UINT16                    CompareValue,
-#   IN      UINT16                    ExchangeValue
-#   );
-ASM_GLOBAL ASM_PFX(InternalSyncCompareExchange16)
-ASM_PFX(InternalSyncCompareExchange16):
-  mov %edx, %eax
-  lock
-  cmpxchgw %r8w, (%rcx)
-  ret
diff --git a/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.asm b/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.nasm
similarity index 88%
rename from OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.asm
rename to OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.nasm
index b23e421abc..048d1f32f6 100644
--- a/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.asm
+++ b/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.nasm
@@ -21,7 +21,8 @@
 ;
 ;------------------------------------------------------------------------------
 
-    .code
+    DEFAULT REL
+    SECTION .text
 
 ;------------------------------------------------------------------------------
 ; UINT16
@@ -32,10 +33,9 @@
 ;   IN      UINT16                    ExchangeValue
 ;   );
 ;------------------------------------------------------------------------------
-InternalSyncCompareExchange16   PROC
+global ASM_PFX(InternalSyncCompareExchange16)
+ASM_PFX(InternalSyncCompareExchange16):
     mov     eax, edx
     lock    cmpxchg [rcx], r8w
     ret
-InternalSyncCompareExchange16   ENDP
 
-    END
diff --git a/OvmfPkg/XenBusDxe/XenBusDxe.inf b/OvmfPkg/XenBusDxe/XenBusDxe.inf
index 3309f53f6b..61f7568e55 100644
--- a/OvmfPkg/XenBusDxe/XenBusDxe.inf
+++ b/OvmfPkg/XenBusDxe/XenBusDxe.inf
@@ -55,8 +55,7 @@
 
 [Sources.X64]
   X64/hypercall.nasm
-  X64/InterlockedCompareExchange16.S
-  X64/InterlockedCompareExchange16.asm
+  X64/InterlockedCompareExchange16.nasm
   X64/TestAndClearBit.S
   X64/TestAndClearBit.asm