Re: [SeaBIOS] [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses.

[Michael S. Tsirkin]

On Fri, Jun 12, 2015 at 02:40:10PM -0400, Kevin O'Connor wrote:
> > (2) The QEMU command line and the effects the command line has on the
> > virtual hardware should not change. However, all of the following have
> > to be updated:
> > the "explicit_ofw_unit_address" property assignments in
> > pxb_dev_initfn() have to be done separately, after all PXBs have been
> > seen, and sorted. This probably requires another "machine init done"
> > notifier.
>
> I admit the sorting of pxb objects just to reverse engineer what
> SeaBIOS expects would not be fun.  Doesn't QEMU have to sort the buses
> anyway to know which secondary bus ranges are associated with each
> root bus?

I guess it can be done - though this means it will break if
we ever support hot-plugging of these roots.
But more importantly, if the sort is by the bus number,
then how is it better than just using the bus number directly?