You say it's in 8.3 development snapshot, but it NO WORKY!
I'm confused is there something additional I need to do inorder to enable virtio driver?
Last I checked it was, really. Screaming doesn't help.
Unfortunate choice of subject line…
Anyway, I just tested the latest iso (2.1-DEVELOPMENT-i386-20120407-1009) running under the latest Virtualbox 4.1.12, and a VM with two virtio-net interfaces doesn't recognize any network interfaces ("No interfaces found!")
I wasn't screaming, it was more a playful thing.
I'm using the AMD64 iso, all I get is a single usbus00 for interfaces when virtio is set for network of kvm.
I even edited the /boot/loader.conf and it doesn't do anything.