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

[Marcel Apfelbaum]

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 :)

Thanks,
Marcel


> > > This patch makes it possible to configure PXB out of the build, and adjusts
> > > the default configs so it's only included on x86 targets.

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