Re: [Xen Hackathon] new PV drivers

[Boris Ostrovsky <boris.ostrovsky@oracle.com>]

On 06/09/2014 05:42 AM, Stefano Stabellini wrote:
> On Mon, 9 Jun 2014, Ian Campbell wrote:
>> On Fri, 2014-06-06 at 14:56 +0100, Anil Madhavapeddy wrote:
>>> On 3 Jun 2014, at 12:47, Stefano Stabellini <stefano.stabellini@eu.citrix.com> wrote:
>>>
>>>> Present (by memory):
>>>> - Julien Grall,
>>>> - Stefano Stabellini,
>>>> - Ian Campbell,
>>>> - Roger Pau Monne,
>>>> - Dario Faggioli,
>>>> - Andrii Tseglytskyi,
>>>> - David Vrabel,
>>>> - Konrad Wilk.
>>>>
>>>> * What new PV devices do we need? What has been done already?
>>> I missed this session, but was wondering about an entropy driver.
>>> We're integrating an OCaml SSL/TLS into MirageOS, and it's not clear
>>> how PV guests should go about getting a strong source of entropy from
>>> the outside world in a reasonably portable way.


Is entropy provided by drivers/char/random.c not sufficient?

-boris


>>>
>>> VirtIO has a RNG [1] -- has anyone got any interest in a PV protocol
>>> for Xen that does the same?
>> IMHO support for these sorts of things is actually one of the few good
>> reasons to be considering support for basic virtio on Xen.
>>
>> Alternatively AIUI a bunch of these sort of virtio devices are just
>> protocols built on top of virtio_serial, so we could perhaps be thinking
>> of repurposing them over Xen's serial PV device. Dave S was
>> investigating the difference between libvirt "serial" and "channel"
>> recently and AIUI the difference was that a channel could be named in
>> order to support bindings to these higher level things (i.e. appearing
>> to the guest as /dev/rng instead of /dev/hvcN).
> However writing a good PV-RNG should be far easier than making virtio
> work properly with Xen PV guests.