--- 2006-06-06/xen/arch/x86/traps.c.0	2006-06-07 09:10:45.000000000 +0200
+++ 2006-06-06/xen/arch/x86/traps.c	2006-06-09 08:35:49.000000000 +0200
@@ -748,7 +748,8 @@ static inline int guest_io_okay(
 #define TOGGLE_MODE() ((void)0)
 #endif
 
-    if ( v->arch.iopl >= (guest_kernel_mode(v, regs) ? 1 : 3) )
+    if ( !vm86_mode(regs) &&
+         v->arch.iopl >= (guest_kernel_mode(v, regs) ? 1 : 3) )
         return 1;
 
     if ( v->arch.iobmp_limit > (port + bytes) )