FWIW, Virtio RNG is natively supported by Linux, NetBSD, and OpenBSD as guests, and hypervisors like Linux KVM/QEMU and OpenBSD VMM/VMD. I use libvirt and virt-manager on Linux which makes it easy to add a Virtio RNG device, but it should be the default, as it is with OpenBSD VMM/VMD.
Ah, I just found --rng in another read of the virt-install manual. This works a lot better than aborting the install and editing the xml and restarting.
