Re: [Qemu-devel] [PATCH 04/13] qdev: add generic qdev_device_add()

[Markus Armbruster]

Markus Armbruster <address@hidden> writes:

> Gerd Hoffmann <address@hidden> writes:
>
>> On 07/10/09 22:51, Paul Brook wrote:
>>>>> I think this is going in the wrong direction. The device tree provides us
>>>>> with a standard way of identifying which bus to add a device to. We
>>>>> should be removing uses of pci_create, not adding new ones.
>>>> Why?
>>>>
>>>> Let me guess: Because pci bus numbers are guest-changeable and thus not
>>>> stable?
>>>
>>> Because I don't think this code need to be bus specific.
>>
>> Parts of the problem are certainly bus-specific though, such as
>> parsing bus addresses.
>
> Yes.
>
> Provide a bus method to parse the addr property?
>
>>> We also need to figure out the naming of multiple similar devices on the 
>>> same
>>> bus. Possibly your "device id" could be used to identify devices on a bus.
>>> e.g. if we wanted two scsi adapters:
>>>
>>>   -device lsi,bus=pci0,id=foo
>>>   -device lsi,bus=pci0,id=bar
>>>   -device scsi-disk,bus=pci0/foo/scsi
>>>   -device scsi-disk,bus=pci0/bar/scsi
>
> Why foo/scsi?  Is there a node "scsi" between the lsi device and the
> disk?  If yes, why?

Got it: because qdev distinguishes between device nodes and bus nodes,
there is a scsi bus node between the lsi device node and the scsi-disk
device node.