On 18.04.19 15:00, Christian Borntraeger wrote: > > > On 18.04.19 14:45, David Hildenbrand wrote: >> On 18.04.19 13:31, Christian Borntraeger wrote: >>> conditional sske is deprecated and a distant future machine (will be one >>> where the IBC will not allow to fully go back to z14) will remove this >>> feature. To prepare for this and allow for the z14 and older cpu model >>> to still run on systems without csske, remove csske from the base (and >> >> will csske feature be a default feature for zNext? Or is it not >> available *at all*. >> >> In case it is not available, baselining and cpu model comparison have to >> be thought about "ignoring csske". >> >>> thus the default models for z10..z14). For compat machines we have to >>> add those back. >> >> Base models are machine-independent. That means, changing base models is >> not supported. > > Why is that? for the expansion?
Yes, and baselining. It's what the QAPI interface promises. > >> Once we introduce new models like here, we can set the >> new base models into stone. > > the new model is easy (and yes I could only disable CSSKE in the base > model for gen15 but not for gen14. > > The problem is that without some kind of fixup for older base models like > z10-z14 expansion will fall back to z9 on anything that no longer has > csske. I'd prefer to do generate the "right" base models right away and not fix them up at runtime. They should never change, so fixing them up at runtime feels wrong. >> Luckily, we already have "ignored_base_feat", maybe we can simply add >> csske there and have it working. > > Yes, maybe we could ignore csske. > Yes, that should at least avoid falling back to a z9. -- Thanks, David / dhildenb
