Re: [Qemu-devel] [PATCH 6/8] pci: Simpler implementation of primary PCI bus

[David Gibson]

On Wed, May 29, 2013 at 07:43:41PM +1000, David Gibson wrote:
> On Thu, May 23, 2013 at 10:16:27PM +1000, David Gibson wrote:
> > On Thu, May 23, 2013 at 02:22:30PM +0300, Michael S. Tsirkin wrote:
> > > On Thu, May 09, 2013 at 10:31:10AM +1000, David Gibson wrote:
> > > > Currently pci_get_primary_bus() searches the list of root buses for one
> > > > with domain 0.  But since host buses are always registered with domain 
> > > > 0,
> > > > this just amounts to finding the only PCI host bus.
> > > > 
> > > > This simplifies the implementation by defining the primary PCI bus to
> > > > be the first one registered, using a global variable to track it.
> > > > 
> > > > Signed-off-by: David Gibson <address@hidden>
> > > 
> > > Or better: can we just fail if there is more than
> > > one root?
> > 
> > That might work, I'll look into doing that.
> 
> So, the difficulty with this is that then any machine with multiple
> PCI bridges could not use pci_nic_init(), since it calls
> pci_get_bus_devfn() which calls pci_find_primary_bus() which would
> always fail.  And using pci_nic_init() is more or less mandatory in
> the machine_init function to support old-style nic configuration.
> 
> Suggestions?

Oh, fwiw, my latest work-in-progress can be had at
        git://github.com/dgibson/qemu.git ('pci' branch)

This is the only comment remaining to be addressed from the last
round, so I'm hoping we can come to some consensus here and I'll
repost.

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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