Re: [Qemu-devel] QEMU: PCI bus name on PowerPC platforms

["Daniel P. Berrange" <berrange@redhat.com>]

On Wed, Mar 05, 2014 at 03:12:40PM +0100, Paolo Bonzini wrote:
> Il 05/03/2014 14:40, Daniel P. Berrange ha scritto:
> > FWIW, I had requested this rename in the past but it was rejected :-(
> > 
> >    http://comments.gmane.org/gmane.comp.emulators.qemu/70783
> 
> I think we should revisit that.
> 
> Path-based bus names are a good idea, but unfortunately it's not how 
> things ended up working.
> 
> We now have two namespaces:
> 
> - one based on the device id + incremental number, where things created
> by the user can be addressed in a forwards-compatible way
> 
> - another based on the bus type as soon as Alex/Markus's patch "qdev:
> Keep global allocation counter per bus", for things created by the board
> (and also by the user, but with no forwards guarantee of compatibility).
> 
> So we could respin your patch, but with NULL bus name instead of "pci.0".
> Just a handful of machines are affected:
> 
> alpha/typhoon.c:    b = pci_register_bus(dev, "pci",
> mips/gt64xxx_pci.c:     phb->bus = pci_register_bus(dev, "pci",
> pci-host/apb.c:    phb->bus = pci_register_bus(DEVICE(phb), "pci",
> pci-host/bonito.c:    phb->bus = pci_register_bus(DEVICE(dev), "pci",
> sh4/sh_pci.c:    phb->bus = pci_register_bus(DEVICE(dev), "pci",
> pci-host/versatile.c:    pci_bus_new_inplace(&s->pci_bus, sizeof(s->pci_bus), DEVICE(obj), "pci",
> 
> plus pseries which has its own rules because it supports multiple PCI
> host bridges, but probably can also be changed from "pci" to NULL.

I'm not sure I understand the effect of changing 'pci' to NULL in this
code, from libvirt's POV. Would using NULL mean we can rely on using
"pci.0" as the default PCI bus name or not ?

Regards,
Daniel
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