able to the guest. Currently, this fixes a boot crash on top of Xen. In the future this will become an issue on KVM as well. Check if northbridge devices are present and do not enable the feature if there are none. [ hpa: backported to 2.6.34 ] Signed-off-by: Frank Arnold LKML-Reference: <1271945222-5283-3-git-send-email-bp@amd64.org> Acked-by: Borislav Petkov Signed-off-by: H. Peter Anvin Cc: K L´ž&x