Linaro-open-discussions May 2022

linaro-open-discussions@op-lists.linaro.org

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1 discussions

Re: Linaro-open-discussions Digest, Vol 19, Issue 1

by Joyce Qi

Hi Jonathon，Lorenzo， Do we have some topic to discuss for the Linaro-open-disscussions next week? Thanks:) Joyce > 在 2022年4月14日，上午8:00，linaro-open-discussions-request@op-lists.linaro.org 写道： > > Send Linaro-open-discussions mailing list submissions to > linaro-open-discussions(a)op-lists.linaro.org > > To subscribe or unsubscribe via email, send a message with subject or > body 'help' to > linaro-open-discussions-request(a)op-lists.linaro.org > > You can reach the person managing the list at > linaro-open-discussions-owner(a)op-lists.linaro.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Linaro-open-discussions digest..." > > Today's Topics: > > 1. Re: LOD Call notes: 22 March 2022 - vCPU Hotplug Update > (Jonathan Cameron) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 13 Apr 2022 19:17:32 +0100 > From: Jonathan Cameron <Jonathan.Cameron(a)Huawei.com> > Subject: [Linaro-open-discussions] Re: LOD Call notes: 22 March 2022 - > vCPU Hotplug Update > To: Ilkka Koskinen <ilkka(a)os.amperecomputing.com> > Cc: linaro-open-discussions(a)op-lists.linaro.org > Message-ID: <20220413191732.00000e4e(a)Huawei.com> > Content-Type: text/plain; charset="US-ASCII" > > On Thu, 31 Mar 2022 11:47:26 -0700 (PDT) > Ilkka Koskinen <ilkka(a)os.amperecomputing.com> wrote: > >> Hi everyone, >> >> On Tue, 22 Mar 2022, Jonathan Cameron via Linaro-open-discussions wrote: >>> Hi All, >>> >>> A quick set of notes on the discussion on vCPU hotplug. >>> >>> Great to have Ed join the discussion. If we are going to >>> have further calls on this topic we may want to move the time to be >>> more friendly for the US. >>> >>> Current status >>> * ACPI spec change via code first route approved. >>> * Kernel patches being reworked / rebased by ARM. Expected to be sent >>> out in 5.19 cycle. >>> * QEMU patches being updated by Huawei. Will do at least some light testing >>> and then push out a public git tree so that others can test - will aim >>> to do this so it aligns with kernel code availability. >>> * Ed (Ampere) gave an update to say they are interested in pushing this >>> forwards ASAP and have customer / OS vendor engagement which will be >>> very useful in moving towards a complete solution, particularly ensuring >>> good test coverage etc. >>> >>> Noted that current QEMU patches may not cover all corner cases, for example >>> live migration of VMs that have vCPUs hotplugged. Might 'just work' >>> but we haven't tested it yet so probably not. >>> >>> Given we didn't really add anything on DOE / SPDM over previous calls, >>> I don't plan to send out anything on that topic this time. >>> >>> Thanks to Joyce for hosting the call. If I noted down anything wrong, >>> or incomplete let the list know. >>> >>> Jonathan >>> -- >>> Linaro-open-discussions mailing list -- linaro-open-discussions(a)op-lists.linaro.org >>> https://collaborate.linaro.org/display/LOD/Linaro+Open+Discussions+Home >> >> Thanks for the great meeting and the update! As Ed mentioned (and you >> wrote above), we're interested in joining the vCPU Hotplug development. > > Hi Ilkka > > Great to have you on board for this. > > Status wise, on QEMU side we have the new interface up and running > (it was a whole 2 lines of code once we'd dealt with some rebasing related issues). > > Rather more changes were needed to make it work sensibly on top of Gavin Shan's > QEMU topology configuration patch set. > https://lore.kernel.org/qemu-devel/20220403145953.10522-1-gshan@redhat.com/ > The code going through some light internal review before we put it up somewhere > public. Note it's definitely not production quality code but it is somewhere > to start from. Given Easter related vacations I doubt we'll get enough > eyes on it until next week. > > We were thrown briefly by the fact there is a recently added > apcica/actbl2.h entry for MADT_ONLINE_CAPABLE but it's a different bit. > Seems x86 folk wanted something similar last year. We'll have to do something > ugly in ACPICA to mangle the name for the new bit to avoid that collision. > Lorenzo, I'm assuming the ACPCIA one line patch to add that define is > something the ARM team will deal with? > > There are some known limitations though that we'll need to sort out before > upstreaming the QEMU support. One of which is SVE currently breaks things. > Plenty of time though as kernel needs to be upstream first anyway. > > Testing wise we are using QEMU on top of QEMU so we can poke corners of the > architecture don't have hardware for (e.g. SVE :). Even on a rubbish x86 > desktop it's not that slow :) > > Lorenzo, any update on kernel side of things or expected time scale for > more information? > > Obviously we have some hacked patches based on Salil's original proposal > that sanity check the QEMU side of things but I suspect the final version > will look rather different :) > > One question on the spec change for Lorenzo. It's not entirely clear > but I think we should not be using _MAT when 'hotplugging' the vCPUs? > For now the QEMU code provides the relevant entries anyway but > it would be nice to drop that if not necessary (it's not a huge > amount of code or complexity though so not a big thing either way). > > Thanks and an early happy Easter to those celebrating on Sunday. > > Jonathan > >> >> Br, Ilkka > > > ------------------------------ > > Subject: Digest Footer > > Linaro-open-discussions mailing list -- linaro-open-discussions(a)op-lists.linaro.org > To unsubscribe send an email to linaro-open-discussions-leave(a)op-lists.linaro.org > > > ------------------------------ > > End of Linaro-open-discussions Digest, Vol 19, Issue 1 > ******************************************************

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Linaro-open-discussions May 2022