Meeting Details

Topic: linaro-open-discussion meeting
Time: Dec 7, 2020 02:00 PM London

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https://linaro-org.zoom.us/j/4417312160

Meeting ID: 441 731 2160
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Meeting ID: 441 731 2160
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Attendees

Wei
Shameerali Kolothum Thodi
lushenming
wanghuiqiang
Zeng Tao
Mike (Linaro)
lumu
Lorenzo (Arm)
Jonathon Cameron
Salil
Jammy
Fangjian
Liudongdong

Agenda

Confirmed topics

VLPI Migration support on Gic V4.1: lushenming (Huawei) - 15 mins
Topic requested by Lorenzo Pieralisi (ARM)
In GICv4.1, migration has been supported except for (directly-injected)
VLPI. And GICv4.1 spec explicitly gives a way to get the VLPI's pending state (which was crucially missing in GICv4.0). So we make VLPI migration
capable on GICv4.1 in this patch set.
(5 min) Intro to the work, then questions (10 min).

vCPU HP: Salil Mehta (Huawei) 25 mins.
Lorenzo has questions + it's an expansive topic.
I would suggest interested people catch up with slides from KVM forum 2020
https://kvmforum2020.sched.com/event/eE4m/challenges-in-supporting-virtual-cpu-hotplug-on-soc-based-systems-like-arm64-salil-mehta-huawei (video not public yet)
(5 min) Open questions statement, then move to discussion.

RMR related topics - follow up on last call: Lorenzo Pieralisi (ARM) - 5 mins
There were outstanding questions around whether PCIe reenumeration could
cause problems here.
(Lorenzo, Shameer, there were a few other open questions around this topic,
do we have any other updates for Monday?)

Generic Initiators: Jonathan Cameron (Huawei) - 5 mins
Very brief intro to GIs + current status + opening for questions.
More detail etc in this email.
https://op-lists.linaro.org/pipermail/linaro-open-discussions/2020-November/000016.html

Previous list

Lorenzo - IORT - Reserve memory regions (RMR) and the RMR flags to free up IOVA.
Jonathon - Generic initiators - pending items
lushenming - VLPI Migration support on Gic V4.1 https://lore.kernel.org/linux-arm-kernel/20201123065410.1915-1-lushenming@huawei.com/
Jonathon - Use of BDF to identify PCI devices in ACPI tables
Jonathon - vCPU hotplug

Under discussion for inclusion from the previous list

~~Jonathan - IOMMU performance work (may need Will Deacon involved from Google)~~

Meeting notes - draft

Organisation - Mike 2 min

We will try to stick to the time limits, any topic can be brought up again.
Thank you all for slides to make it easier for participants to prepare.

VLPI Migration support on Gic V4.1: lushenming (Huawei) - 15 mins

L has fix in QEMU for repeated resetting
LP : no concussion yet, but will solve on the next post
LP will help move this forward
Jammy to ensure translations were good.
L: have no good idea about the proper restoring point, need LP's suggestions
LP : please keep me in the loop this is interesting.

vCPU HP: Salil Mehta (Huawei) 25 mins.

Presentations to bring the discussions together
Arm to start discussions from KVM forum, it is not a month later
Need to start reviewing - Lorenzo can you help start a discussion with Arch team in Arm.
- LP - is the sizing a problem to upstream for QEMU ? SM - most changes appear doable, not had a good review yet, did speak to RedHat they say this is in line.
- LP - Kubernetes require, will they discuss alternatives, or does the fact that it is working on X86 entrench the thinking and that camp say its fine as it is. Has ACPI been discussed?
- LP - I can take this up with Arm Architecture team

RMR related topics - follow up on last call: Lorenzo Pieralisi (ARM) - 5 mins

LP : action from the last meeting. Host bridge must not be enumerated - two reasons
SPEC to come out soon - is this ok
LP will have look to check for holes in the spec, need a proper look
Wanghuiqiang - concerned about RMR

Generic Initiators: Jonathan Cameron (Huawei) - 5 mins

Action items

LP follow up on VLPI Migration support on Gic V4.1:
LP Followup on vCPU HP:

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