diff --git a/OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.S b/OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.S
deleted file mode 100644
index c2735d2c65..0000000000
--- a/OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.S
+++ /dev/null
@@ -1,52 +0,0 @@
-#------------------------------------------------------------------------------
-#
-# Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>
-# This program and the accompanying materials
-# are licensed and made available under the terms and conditions of the BSD License
-# which accompanies this distribution.  The full text of the license may be found at
-# http://opensource.org/licenses/bsd-license.php.
-#
-# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
-# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
-#
-#------------------------------------------------------------------------------
-
-#------------------------------------------------------------------------------
-#  VOID
-#  EFIAPI
-#  IoReadFifo8 (
-#    IN UINTN                  Port,
-#    IN UINTN                  Size,
-#    IN VOID                   *Buffer
-#    );
-#------------------------------------------------------------------------------
-ASM_GLOBAL ASM_PFX(IoReadFifo8)
-ASM_PFX(IoReadFifo8):
-    movw    4(%esp), %dx
-    movl    8(%esp), %ecx
-    pushl   %edi
-    movl    16(%esp), %edi
-rep insb
-    popl    %edi
-    ret
-
-
-#------------------------------------------------------------------------------
-#  VOID
-#  EFIAPI
-#  IoWriteFifo8 (
-#    IN UINTN                  Port,
-#    IN UINTN                  Size,
-#    IN VOID                   *Buffer
-#    );
-#------------------------------------------------------------------------------
-ASM_GLOBAL ASM_PFX(IoWriteFifo8)
-ASM_PFX(IoWriteFifo8):
-    movw    4(%esp), %dx
-    movl    8(%esp), %ecx
-    pushl   %esi
-    movl    16(%esp), %esi
-rep outsb
-    popl    %esi
-    ret
-
diff --git a/OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.asm b/OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.nasm
similarity index 89%
rename from OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.asm
rename to OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.nasm
index f7d65c49af..faa22e97d4 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.asm
+++ b/OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.nasm
@@ -11,9 +11,7 @@
 ;
 ;------------------------------------------------------------------------------
 
-    .586P
-    .model  flat,C
-    .code
+    SECTION .text
 
 ;------------------------------------------------------------------------------
 ;  VOID
@@ -24,7 +22,8 @@
 ;    IN VOID                   *Buffer
 ;    );
 ;------------------------------------------------------------------------------
-IoReadFifo8 PROC
+global ASM_PFX(IoReadFifo8)
+ASM_PFX(IoReadFifo8):
 
     mov     dx, [esp + 4]
     mov     ecx, [esp + 8]
@@ -34,9 +33,6 @@ rep insb
     pop     edi
     ret
 
-IoReadFifo8 ENDP
-
-
 ;------------------------------------------------------------------------------
 ;  VOID
 ;  EFIAPI
@@ -46,7 +42,8 @@ IoReadFifo8 ENDP
 ;    IN VOID                   *Buffer
 ;    );
 ;------------------------------------------------------------------------------
-IoWriteFifo8 PROC
+global ASM_PFX(IoWriteFifo8)
+ASM_PFX(IoWriteFifo8):
 
     mov     dx, [esp + 4]
     mov     ecx, [esp + 8]
@@ -56,7 +53,3 @@ rep outsb
     pop     esi
     ret
 
-IoWriteFifo8 ENDP
-
-    END
-
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.inf b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.inf
index 071737edef..f163de3d3f 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.inf
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.inf
@@ -36,8 +36,7 @@
   QemuFwCfgPeiDxe.c
 
 [Sources.IA32]
-  Ia32/IoLibExAsm.asm
-  Ia32/IoLibExAsm.S
+  Ia32/IoLibExAsm.nasm
 
 [Sources.X64]
   X64/IoLibExAsm.asm
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSecLib.inf b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSecLib.inf
index 71beacbaf9..5c5c5c7f40 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSecLib.inf
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSecLib.inf
@@ -34,8 +34,7 @@
   QemuFwCfgSec.c
 
 [Sources.IA32]
-  Ia32/IoLibExAsm.asm
-  Ia32/IoLibExAsm.S
+  Ia32/IoLibExAsm.nasm
 
 [Sources.X64]
   X64/IoLibExAsm.asm