Re: [Qemu-devel] [PATCH 2/4] virtio-rng-pci: create a default backend if none exists

[Paolo Bonzini]

Il 26/10/2012 22:16, Anthony Liguori ha scritto:
> So it's still a failure, just a different message.
> 
> But this does suggest that we shouldn't add it to the default machine on
> !Linux because we don't want the default machine failing.

We need to add it to all machines, because the machine signature should
not depend on the host OS.  However, it does suggest we need a null
backend as a fallback.

> Perhaps we can find better default backends on !Linux...

Yes, rdrand would be one.

>> > What if the default was changed to /dev/hwrng but an older Linux
>> > distro didn't have the device file at all?
> It would throw an error gracefully.

Perhaps the default backend can be created with a function that tries
multiple things and at worst settles on rng-null.

Paolo