[XEN] IOPL is ignored for VM86 mode port accesses. Fix Xen

emulation to match native behaviour.
Signed-off-by: Jan Beulich <jbeulich@novel..com>

diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index 74de928a374e77aa2c99572497188a92074279d2..031ee87e4ff2419e54c7185971d6c8d055907e10 100644 (file)
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -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) )