Re: [Qemu-devel] [RFC] pxb: Restrict to x86

[David Gibson]

On Sun, Jan 08, 2017 at 10:17:12AM +0200, Marcel Apfelbaum wrote:
> On 01/06/2017 09:41 PM, Michael S. Tsirkin wrote:
> > On Fri, Jan 06, 2017 at 08:13:11AM +0200, Marcel Apfelbaum wrote:
> > > On 01/06/2017 07:04 AM, David Gibson wrote:
> > > > The PCI Expander Bridge (PXB) device is essentially a hack to allow
> > > > different PCIe devices to be assigned to different NUMA nodes on x86.  
> > > > Each
> > > > PXB is sort-of a separate PCI host bridge, except that its config space
> > > > is shared with the config space of the main PCI host bridge, rather than
> > > > being independent.
> > > > 
> > > 
> > > Hi David,
> > > 
> > > > This is only necessary if the platform doesn't (easily) allow truly
> > > > independent PCI host bridges.  AFAIK that's just x86.
> > > > 
> > > 
> > > Indeed, it is possible to support independent PCI host bridges on x86 by
> > > using a separate MMCONFIG space for each one and enable separate PCI 
> > > domains.
> > > We simply didn't need this until now, but maybe will be implemented it in 
> > > the future.
> > 
> > In fact I would say that's the cleanest way to do this on q35.
> 
> Message received :)

Just so I'm clear, these last two comments are essentially suggesting
a follow up cleanup on x86, rather than suggesting a different
approach for non-PC platforms, yes?

If there are no objections to my original patch do you want to take it
through your tree Michael, or should I take it through mine?

-- 
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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