I have no idea what are the experiences of other people running FreeBSD in KVM but I could not get pass grub trying to install amd 9.3 or amd 10 on Red Hat 6.5. I know it is not FreeBSD problem but it is kind funny that Red Hat is racing to implement containers which is equivalent of FreeBSD jails introduced 2000 while FreeBSD is racing to add bhyve which is more or less KVM for FreeBSD.