(This email has sent to the QEMU developer ML, but seems nobody give a clear answer, I begin to suspect if it's a stupid question :-)
Hello QEMU Users, We all know that there is a virtio-rng device can be para-virtualised from the host to guest in case of a real RNG HW exists in the host, my question is: Can we get some performance gain to use the 'virtio-rng' device if there isn't a real RNG HW in host, in this case, what's the default back-end of the virtio -rng device? For my scenario, I don't want to use a virtio-rng device if the host doesn't have a RNG HW, because the guest will get a fake RNG HW with virtio-rng device (/sys/ devices/virtual/misc/hw_random/rng_current), which is not expected. But if virtio-rng is not used, I don't know how the guest get the entropy from the host, the most concern is performance. IOW, what's the difference between virtio-rng used and not if there isn't a RNG HW in host? Thanks!
