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