Re: [Qemu-devel] [PATCH 0/6] add paravirtualization hwrng support

[Paolo Bonzini]

Il 26/10/2012 17:42, Anthony Liguori ha scritto:
>> Maybe rdrand, but that's just a chardev---so why isn't this enough:
>>
>>   -chardev file,source=on,path=/dev/hwrng,id=chr0  -device 
>> virtio-rng-pci,file=chr0
>>   -chardev rdrand,id=chr0                          -device 
>> virtio-rng-pci,file=chr0
>>   -chardev socket,host=localhost,port=1024,id=chr0 -device 
>> virtio-rng-pci,rng=chr0,egd=on
>>
>> (which I suggested in my reply to Amit)?
> 
> I don't like overloading chardev to representate any !block device
> backend which is what I fear we're doing here.

Like -chardev msmouse you mean? ;)

> EGD is more than just a dumb pipe of data too.  It's got a way to query
> available entropy.  I have a strong suspicion that over time, we'll add
> methods to virtio-rng to query available entropy.  That would mean
> adding a backend specific ioctl to the chardev layer which is pretty
> ugly.
> 
> The overhead of creating a separate backend to begin with is extremely
> small.  We're talking about dozens of lines of code.  So I don't see
> what the problem is.

If you just make rng-random take a chardev, I have no problem with the
series.

Paolo