A missing "nested" patch, maybe?

[walt]

/home/wa1ter/src/kvm-userspace/qemu/target-i386/helper.c:1548: error:
‘kvm_nested’ undeclared (first use in this function)

I added "extern int kvm_nested" to helper.c and it seems to work,
but I'm not sure what 'nested' is supposed to do.