commit b65d6e17 upstream.

This feature is not supported inside KVM guests yet, because we do not emulate
MSR_IA32_XSS.  Mask it out.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>