diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index e6a61520d5..0d242739b1 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -5128,6 +5128,7 @@ static void subpage_mmio_write_emulate(
         return;
     }
 
+    addr += offset;
     switch ( len )
     {
     case 1: