On 15.02.2018 17:42, Janosch Frank wrote: > On 15.02.2018 17:08, David Hildenbrand wrote: >> On 15.02.2018 16:43, Janosch Frank wrote: >>> use_cmma in kvm_arch means that the vm is allowed to use cmma, whereas >>> use_cmma in the mm context means it has been used before. Let's rename >>> the kvm_arch one to has_cmma >> >> Unfortunately all naming related to CMM(A) is already screwed up. >> >> If the guest can issue the ESSA instruction, it has the CMM facility. We >> used to provide it to him by enabling the CMMA control - the >> "interpretation facility". We could right now fully emulate it (which is >> what we do when we dirty track changes). >> >> At least in the CPU model we did it right. (the feature is called "cmm") >> >> But anyhow, we only provide the CMM facility to the guest right now if >> we have CMMA, so keeping the name "cmma" here is not completely wrong. >> >>> >>> Also let's introduce has_pfmfi, so we can remove the pfmfi disablement >> >> Mixed feelings. has_pfmfi sounds more like "this guest has the PFMFI >> feature", which is something related to vSIE. It is really more >> "use_pfmfi". Because we provide the PFMF instruction either way (by >> emulating it - it belongs to edat1). >> >> Can we name this "use_cmma" and "use_pfmfi" and "use_skf", because that >> is actually what we do? > > As long as we have a difference between the arch and the context one and > the implementation of the patches are not a problem, sure. > > We could also invert them and use emulate_pfmf or intercept_* which is > more specific about what we actually (don't) do. I think "using the interpretation facility" is good enough. Because that is exactly what we do, independent of availability of the instruction towards the guest. emulate_pfmf might be misleading, e.g. if the guest doesn't have EDAT1 and we fake it away - emulate_pfmf is set but we don't emulate it. We inject an exception right away. intercept_* would work, however the would then have to be intercept_essa instead of cmma. Not sure if that is easier to read. > >> >> The thing in the mm context should rather be renamed to "uses_cmm(a)" or >> "used_cmm(a)". > > Yes, I like uses more, the rest of the gang likes used, now feel free to > propose something entirely different :) > > If there's not much that speaks against the first two patches, I'd spin > them off to merge them earlier, the use_cmma cleanup has been on my list > for a long time. Thoughts? > Jup, please resend, they make sense on their own. -- Thanks, David / dhildenb -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
