Re: Configuration vs. compat hints [was Re: [Qemu-devel] [PATCHv3 03/13] qemu: add routines to manage PCI capabilities]

Anthony Liguori
2009-06-15T15:07:54Z

Avi Kivity wrote:
>
> I'd object to any implicit addressing rules. If we have to say
> target=2,lun=7,street=8,city=9,state=99,zip=12345 instead of
> index=8345345235 so be it.

The next observation is that while we expand the SCSI addressing, the
current propose flattens the PCI hierarchy (i.e. pci_addr=00:01.0).

An alternative would be to either always expand or always flatten
addressing. I think the later has a lot of merit. Consider:

-controller type=lsi1234,addr=00:01,name=blah
-controller-disk controller=blah,addr=00:01,name=sda

-controller type=ide,addr=00.02,name=ide
-controller-disk controller=ide,addr=3,name=hdd

-drive file=foo.img,controller-disk=sda
-drive file=bar.img,controller-disk=hdd

This means that addr's format depends on the parent device node which is
a bit less explicit than the previous example. However, it is much more
consistent and easier to implement. Basically, when adding a device to
it's parent, you hand the parent the "addr" field and that lets you say
where you want to sit on the bus.

Regards,

Anthony Liguori