Re: [PATCH v4 4/5] cpu_map: Add POWER11 cpu model support

On Tue, Apr 29, 2025 at 13:03:12 +0100, Daniel P. Berrangé wrote: > On Tue, Apr 29, 2025 at 01:42:22PM +0200, Peter Krempa wrote: > > On Tue, Apr 29, 2025 at 12:36:40 +0100, Daniel P. Berrangé wrote: > > > On Tue, Apr 15, 2025 at 04:13:08AM -0400, Narayana Murty N wrote: > > > > <model usable='unknown' vendor='IBM'>POWER7</model> > > > > <model usable='unknown' vendor='IBM'>POWER8</model> > > > > <model usable='unknown' vendor='IBM'>POWER9</model> > > > > + <model usable='unknown' vendor='IBM'>power11</model> > > > > > > QEMU allows both upper & lowercase for CPU names, and libvirt > > > has stuck with uppercase historically. > > > > > > What's the justification for changing this approach for > > > power11 ? > > > > qemu itself reports the model lowercase now. In v2 of this series I've > > pointed that out because defining this caused test data to change which > > was suspiciuous. > > By 'reports the model lowercase' i presume you're referring to '-cpu help' > and/or 'query-cpu-definitions' ? That doesn't seem to be a new change > either though. I've not gone far back, but qemu 8.2.0 seems to already > be using lowercase. > > So I'm still wondering why we're changing our decision about CPU naming > /now/ with power11 ? The commit message needs to explain and justify > this change. Well, when I replied to the original patch, my memory was telling me QEMU switched to lower case names and had to add compatibility code to translate our existing upper case names. And adding a new CPU model looked like a good excuse to stop doing that (for new models of course) and just define the model in lower case. Now that you're questioning this I tried to find evidence and I could not find it :-( So there are two options... either I'm bad at searching or I my memory confused this with dropping version suffixes (_vX.Y) in virCPUppc64ConvertLegacy. Or both options are true at the same time :-) Maybe Andrea can remember more, I think he was involved in all this ages ago.