--- a/arch/x86/xen/enlighten.c  2010-08-05 20:35:13.000000000 -0400
+++ b/arch/x86/xen/enlighten.c  2010-08-05 20:35:22.000000000 -0400
@@ -776,6 +776,7 @@
 {
 	cr4 &= ~X86_CR4_PGE;
 	cr4 &= ~X86_CR4_PSE;
+	cr4 &= ~X86_CR4_OSXSAVE;

 	native_write_cr4(cr4);
 }