KVM: VMX: Ignore segment G and D bits when considering whether we can…

… virtualize

We will enter the guest with G and D cleared; as real hardware ignores D in
real mode, and G is taken care of by the limit test, we allow more code to
run in vm86 mode.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

arch/x86/kvm/vmx.c

@@ -3320,7 +3320,7 @@ static bool rmode_segment_valid(struct kvm_vcpu *vcpu, int seg)
 		return false;
 	if (var.limit < 0xffff)
 		return false;
-	if ((ar | (3 << AR_DPL_SHIFT)) != 0xf3)
+	if (((ar | (3 << AR_DPL_SHIFT)) & ~(AR_G_MASK | AR_DB_MASK)) != 0xf3)
 		return false;
 
 	return true;