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

[Pierre Morel <pmorel@linux.ibm.com>]

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