Messages in this thread | | | Subject | Re: random(4) driver questions | From | Sasha Levin <> | Date | Mon, 27 Jun 2011 11:08:13 -0400 |
| |
On Mon, 2011-06-27 at 10:54 -0400, Ted Ts'o wrote: > > What happens to /dev/random when it runs on > > a virtual machine and all the things it relies on > > for entropy get virtualised away? > > > > The server that the VM is hosted on will usually > > have plenty of entropy, often a hardware RNG. > > Is there an interface that makes that visible > > from the VM? Perhaps a virtual "hardware" > > RNG driven by /dev/urandom on the host? > > Yes, paravirtualizing the random number generator would be a big help. > Probably what I would do is to periodically add entropy from the host > OS to the guest OS, via some paravirt channel. This would add a new > "catastrophic reseeding", and if the virtual guest can mix in some > other unknown material, again that can only help.
virtio has a 'virtio-rng' device which does just that.
--
Sasha.
| |