VirtualBox has fast virtualization support (usually faster than QEMU)
You need to load the vboxdrv kernel module and a mounted /proc filesystem.
% mount -t procfs proc /proc
% kldload vboxdrv
For bridged networking you also need to load the vboxnetflt kernel module.
% kldload vboxnetflt
You also have to add all users to your vboxusers group in order to use vbox.
% pw groupmod vboxusers -m jerry
Running VirtualBox as non-root user may fail with a fatal error
NS_ERROR_FACTORY_NOT_REGISTERED. In this case delete /tmp/.vbox-*-ipc file.
Check wiki page for known issues and troubleshooting:
Please report any problems to emulation@. Thanks!