diff -r 5f997b5b8a58 xen/arch/x86/traps.c
--- a/xen/arch/x86/traps.c	Wed Jan 30 15:19:22 2008 +0000
+++ b/xen/arch/x86/traps.c	Thu Jan 31 07:49:29 2008 -0800
@@ -2621,8 +2621,6 @@ asmlinkage void do_device_not_available(
 {
     struct vcpu *curr = current;
 
-    BUG_ON(!guest_mode(regs));
-
     setup_fpu(curr);
 
     if ( curr->arch.guest_context.ctrlreg[0] & X86_CR0_TS )