https://bugzilla.kernel.org/show_bug.cgi?id=206579 --- Comment #37 from Anthony (anthonysanwo@xxxxxxxxxxxxxx) --- Created attachment 287701 --> https://bugzilla.kernel.org/attachment.cgi?id=287701&action=edit Perf_stat_anthony_apicv (In reply to Suravee Suthikulpanit from comment #32) > (In reply to Anthony from comment #28) > > Created attachment 287685 [details] > > avic_inhibit_reasons-anthony > > > > Hi I also just wanted to give my observations I have found when testing the > > patches. > > > > I confirm I also don't have don't have crashes relating to the original > > report. > > > > I have been trying out the SVM AVIC patches since around the first patch > > that was submitted but never got round to documentation my testing until > > recently. > > > > I can't remember the specific patch set/kernel version I tried but I > > remember having avic apparently working with when synic + stimer where > > enabled but not without. If my understanding is correctly this shouldn't be > > the case as synic is meant to be a case when avic is permanently disabled. > > > > This is still the case with current patchset. > > > > In summary I can get avic reporting it's working according to perf stat and > > trace logs when synic is on but not working when synic is off. Using > > EPYC-IBPB or passthrough doesn't change the avic_inhibit_reasons. > > > > With Synic I get avic_inhibit_reasons - 10 > > With Synic+Stimer off I get - 0 > > > > > > To note I am using arch linux + qemu 4.2 + linux-mainline-5.6.0-rc2. > > > > Please see a small trace log of synic on vs off, domain capabilities, perf > > stat and patches used. > > > > These were recording once the VM was launched and sitting at the login > > screen. > > > > Please let me know if there is any other info I get provide to help. > > Thanks for the observation info, and your observation makes sense. AVIC is > also deactivated w/ synic enabled. > (https://elixir.bootlin.com/linux/v5.6-rc3/source/arch/x86/kvm/hyperv.c#L773) > > Thanks, > Suravee I see. I remember reading through your patchset and trying work things out good to see my basic understanding wasn't too far off :) If it's not too much of a bother I was wondering if you could list the requirements needed to enable avic from a kvm/qemu setup. I just wanted to check if I am missing anything on my side as I am not 100% sure on how to tell avic is working looking a trace, perf stat/live. I did a perf stat from when the vm was launch via libvirt to about when it gets to the login screen I about 36 "kvm_apicv_update_request".The attachement has a full output if that is of use. I also got a trace of this but as I redirected all the output to a file I ended up with quite a large file(462MB). So I wanted to see if there is anything I should be looking out for in the trace to see if avic is working as intended. Also, if you don't mind could you show a sample of trace where avic is working. -- You are receiving this mail because: You are watching the assignee of the bug.
