Re: [Qemu-devel] [RFC PATCH v2 1/3] virtio-bus : Introduce VirtioBus.

[Peter Maydell]

On 29 November 2012 13:47, Konrad Frederic <address@hidden> wrote:
> On 29/11/2012 14:09, Peter Maydell wrote:
>> I suspect that qbus_find_recursive should be doing an
>> object_class_dynamic_cast() to check that the bus is of a suitable
>> type, rather than the
>>      (strcmp(object_get_typename(OBJECT(bus)), bus_typename) != 0)
>> which it does at the moment.
>
> Yes, but we can cast VIRTIO_BUS in BUS no ?
> So in this case we could plug VirtioDevice in BUS and that's not what we
> want ?

I don't understand what you're asking. qbus_find_recursive()
looks for a bus which might be specified either by name or by
bus type. At the moment it insists on an exact type match
(so if you ask for a virtio-bus you have to provide a virtio-bus
object, not a subclass of virtio-bus); it should do a dynamic
cast, so anything which is a virtio-bus or a subclass of that
will do. Yes, if you say "please find me any bus which is a
bus of any kind" then you'll get something wrong back -- so
don't do that. In particular, since VirtioDevice sets its
bus_type to TYPE_VIRTIO_BUS then we will ask for that, and
anything which isn't a virtio bus (or subclass) won't be found.

-- PMM