xsave

Apply this patch before compiling Linux kernel for EC2 as specified in http://ec2-downloads.s3.amazonaws.com/user_specified_kernels.pdf. It is not clear whether this patch is required for the kernel to be usable or bootable in EC2.

--- arch/x86/xen/enlighten.c~   2011-01-21 11:38:22.545113000 +0700
+++ arch/x86/xen/enlighten.c    2011-01-21 03:35:59.011543002 +0700
@@ -797,6 +797,7 @@
 {
        cr4 &= ~X86_CR4_PGE;
        cr4 &= ~X86_CR4_PSE;
+       cr4 &= ~X86_CR4_OSXSAVE;
 
        native_write_cr4(cr4);
 }