[libvirt] [PATCH 2/2] qemu: Enable NUMA node tag in pci-root for PPC64

[Daniel P. Berrange]

On Tue, Nov 08, 2016 at 05:35:38PM +0530, Shivaprasad G Bhat wrote:
> This patch addresses the same aspects on PPC the bug 1103314 addressed
> on x86.
> 
> PCI expander bus creates multiple primary PCI busses, where each of these
> busses can be assigned a specific NUMA affinity, which, on x86 is
> advertised through ACPI on a per-bus basis.
> 
> For SPAPR, a PHB's NUMA affinities are assigned on a per-PHB basis, and
> there is no mechanism for advertising NUMA affinities to a guest on a
> per-bus basis. So, even if qemu-ppc manages to get some sort of multi-bus
> topology working using PXB, there is no way to expose the affinities
> of these busses to the guest. It can only be exposed on a per-PHB/per-domain
> basis.
> 
> So, enable NUMA node tag in pci-root controller on PPC.

That doesn't really solve the bug above properly - your solution here
only works if all the PCI devices (whether emulated or host-assigned)
are to be associated with the same guest NUMA node. This is a pretty
restrictive setup and so of limited use IMHO.

It seems like to solve this requires that we create multiple PCI Host
Bridges ?

Regards,
Daniel
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