Re: qtest with multiple driver instances

[Christian Schoenebeck <qemu_oss@crudebyte.com>]

On Donnerstag, 24. September 2020 15:50:43 CEST Thomas Huth wrote:
> On 24/09/2020 13.57, Christian Schoenebeck wrote:
> > Hi,
> > 
> > I'm currently puzzled with what looks like a limitation of the qtest
> > infrastructure: am I right that it's not possible to use multiple
> > instances of the same driver with qtests?
> > 
> > Purpose: I need to add test cases for the 9p 'local' fs driver. So far we
> > only have 9p qtests using the 'synth' fs driver. The problem is, both
> > driver instances would pop up with the same QEMU driver name
> > ("virtio-9p-pci"), and AFAICS qtests in general reference their driver
> > instance by driver name only, which must be a) a unique driver name and
> > b) must match the official QEMU driver name and c) all qtest driver
> > instances are in a global space for all qtests.
> > 
> > Is there any workaround or something that I didn't see? Like letting
> > qtests
> > reference a driver instance by PCI address or something?
> > 
> > Right now the only option that I see is a hack: forcing one driver
> > instance to use a different bus system like e.g. -> "virtio-9p-ccw" vs.
> > "virtio-9p-pci".
> > 
> > Any hint appreciated!
> 
> I assume you are referring to the "qos" framework within the qtests? I
> hope Laurent, Paolo or Emanuele can help with that question (now all on
> CC:)...
> 
>  Thomas

Yes, it looks like it is based on the qos subsystem underneath, i.e.:
tests/qtest/libqos/qgraph.h

Maybe I can use qos_node_contains() to make 2 "virtio-9p-pci" driver instances 
accessible for different qtests? It just seems there is no existing code doing 
that already, otherwise I could just copy & paste.

Best regards,
Christian Schoenebeck