Re: [PATCH v1] s390x: kvm-unit-tests: a PONG device for Sub Channels tests

[Halil Pasic <pasic@linux.ibm.com>]

On Thu, 14 Nov 2019 11:38:23 +0100
Cornelia Huck <cohuck@redhat.com> wrote:

> On Wed, 13 Nov 2019 20:02:33 +0100
> Pierre Morel <pmorel@linux.ibm.com> wrote:
> 
> Minor nit for $SUBJECT: this isn't a kvm-unit-tests patch, that's just
> one consumer :)

And subchannel is one word in s390-speak.

> 

[..]

> Some questions regarding this device and its intended usage:
> 
> - What are you trying to test? Basic ccw processing, or something more
>   specific? Is there any way you can use the kvm-unit-test
>   infrastructure to test basic processing with an existing device?

I'm also curious about the big picture (what is in scope and what out
of scope). Your design should be evaluated in the light of intended
usage.

BTW have you had a look at this abandoned patch-set of mine:

https://lists.gnu.org/archive/html/qemu-devel/2017-11/msg04220.html

We made some different design decisions, while aiming essentially for the
same. Maybe it's due to different scope, maybe not. For instance one
can't test IDA with PONG, I guess.

Regards,
Halil

> - Who is instantiating this device? Only the kvm-unit-test?
> - Can you instantiate multiple instances? Does that make sense? If yes,
>   it should probably not request a new chpid every time :)
> - What happens if someone instantiates this by hand? The only drawback
>   is that it uses up a subchannel and a chpid, right?
> - Do you plan to make this hotpluggable later?
> 
>