After adding "args: -xsave" to vmid.conf, I got error belowanother possibility:
http://lists.freebsd.org/pipermail/freebsd-amd64/2013-February/015136.html
http://forums.freebsd.org/showthread.php?p=236494
Seem that cpuflag +xsave can hang boot of freebsd
so you can try to add in vmid.conf
args: -cpu kvm64,-xsave
Code:
kvm: -xsave: invalid option