http://netbsd.i2p/docs/guide/en/chap-virt.html
In a VM, this is ideally
provided by the host machine, which has greater access to the
underlying hardware. You can easily attach a VirtIO random number
generator device with the following arguments to QEMU: -object rng-random,filename=/dev/urandom,id=viornd0 \
-device virtio-rng-pci,rng=viornd0 This requires no extra configuration on the host machine.