Re: [PATCH 0/2] s390x: ccw: A simple test device for virtio CCW

[Pierre Morel]

On 8/30/21 10:42 PM, Halil Pasic wrote:
> On Mon, 30 Aug 2021 11:51:51 +0200
> Christian Borntraeger <borntraeger@de.ibm.com> wrote:
>
> > On 27.08.21 12:50, Pierre Morel wrote:
> > > Hello All,
> > >
> > >
> > > This series presents a VIRTIO test device which receives data on its
> > > input channel and sends back a simple checksum for the data it received
> > > on its output channel.
> > >    
> > > The goal is to allow a simple VIRTIO device driver to check the VIRTIO
> > > initialization and various data transfer.
>
> Can you please elaborate a little on the objectives.

Yes I will, but I must think a lot more about it, I think doing the 
specifications you speak about later in this response is the right way 
to do it.


> > > For this I introduced a new device ID for the device and having no
> > > Linux driver but a kvm-unit-test driver, I have the following
> > > questions:
> >
> > I think we should reserve an ID in the official virtio spec then for such a 
> > device?
> > Maybe also add mst for such things.
>
> I agree having ID reserved is a good idea. But then if we are going to
> introduce an official test device, I believe we should write a
> specification for it as well. Yes having the guarantee that test devices
> and real devices won't mix is a value in itself, but if we had a
> standardized test device, whoever does work with it would not have to
> ask themselves is this test device compatible with this test device
> driver.

Yes right.

> >    
> >
> > > Is there another way to advertise new VIRTIO IDs but Linux?
> > > If this QEMU test meet interest, should I write a Linux test program?
>
> You may not simply claim and advertise a VIRTIO ID. The virtio ids
> are allocated by the virtio standardisation body, and the list of the
> IDs reserved in the v1.1-cs01 incarnation of the spec can be found here:
> https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/virtio-v1.1-cs01.html#x1-1930005
>
> For how to contribute to the virtio specification please take look at
> this:
> https://github.com/oasis-tcs/virtio-admin/blob/master/README.md

Thanks, I will go this way.


Thanks for these constructive answers,

Regards,
Pierre



--
Pierre Morel
IBM Lab Boeblingen