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

[Halil Pasic]

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.

> > 
> > 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.

>   
> 
> > 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

> > Regards,
> > Pierre
> > 
> > 
> > Pierre Morel (2):
> >    virtio: Linux: Update of virtio_ids
> >    s390x: ccw: A simple test device for virtio CCW
> > 
> >   hw/s390x/meson.build                        |   1 +
> >   hw/s390x/virtio-ccw-pong.c                  |  66 ++++++++
> >   hw/s390x/virtio-ccw.h                       |  13 ++
> >   hw/virtio/Kconfig                           |   5 +
> >   hw/virtio/meson.build                       |   1 +
> >   hw/virtio/virtio-pong.c                     | 161 ++++++++++++++++++++
> >   include/hw/virtio/virtio-pong.h             |  34 +++++
> >   include/standard-headers/linux/virtio_ids.h |   1 +
> >   8 files changed, 282 insertions(+)
> >   create mode 100644 hw/s390x/virtio-ccw-pong.c
> >   create mode 100644 hw/virtio/virtio-pong.c
> >   create mode 100644 include/hw/virtio/virtio-pong.h
> >