Re: [Qemu-devel] [PATCH 4/9] Add S390x virtio machine bus

[Gerd Hoffmann]

> +VirtIOS390Bus *s390_virtio_bus_init(ram_addr_t *ram_size)
> +{
> +    VirtIOS390Bus *bus;
> +
> +    bus = (VirtIOS390Bus *)qbus_create(&s390_virtio_bus_info, NULL, 
> "s390-virtio");

While a cast works the political correct way to do this is using DO_UPCAST.

Also I'd suggest to add a sysbus -> s390-virtio bus bridge device, so 
your bus gets properly hooked up in the device tree.  Have a look at the 
(quite simple) "isabus-bridge" device in isa-bus.c, which is used with 
'qemu -M isapc'.  You'll see the s390-virtio bus and all virtio devices 
attached to it in 'info qtree' then.

> +    bus = (VirtIOS390Bus *)dev->qdev.parent_bus;

DO_UPCAST().

> +VirtIOS390Device *s390_virtio_bus_console(VirtIOS390Bus *bus)
> +{
> +    return bus->console;
> +}

What this is needed for?

cheers,
  Gerd