On 2/9/21 5:19 PM, Thomas Huth wrote: > On 09/02/2021 17.14, Janosch Frank wrote: >> On 2/9/21 5:08 PM, Claudio Imbrenda wrote: >>> On Tue, 9 Feb 2021 09:15:54 -0500 >>> Janosch Frank <frankja@xxxxxxxxxxxxx> wrote: >>> >>>> KVM and QEMU handle a SIGP stop and store status in two steps: >>>> 1) Stop the CPU by injecting a stop request >>>> 2) Store when the CPU has left SIE because of the stop request >>>> >>>> The problem is that the SIGP order is already considered completed by >>>> KVM/QEMU when step 1 has been performed and not once both have >>>> completed. In addition we currently don't implement the busy CC so a >>>> kernel has no way of knowing that the store has finished other than >>>> checking the location for the store. >>>> >>>> This workaround is based on the fact that for a new SIE entry (via the >>>> added smp restart) a stop with the store status has to be finished >>>> first. >>>> >>>> Correct handling of this in KVM/QEMU will need some thought and time. >>> >>> do I understand correctly that you are here "fixing" the test by not >>> triggering the KVM bug? Shouldn't we try to trigger as many bugs as >>> possible instead? >> >> This is not a bug, it's missing code :-) >> >> We trigger a higher number of bugs by running tests and this workaround >> does exactly that by letting Thomas use the smp test in the CI again. > > Alternatively, we could use report_xfail here to make the test pass, but > still have the problem reported so that we do not forget to fix it later. > > Thomas > I have no strong opinion on that although I'll need to have a look if our CI flags XPASS/XFAIL as fails.
