Hi James,

From: James Morse james.morse@arm.com Sent: Friday, February 24, 2023 3:12 PM To: linaro-open-discussions@op-lists.linaro.org Cc: Salil Mehta salil.mehta@huawei.com; salil.mehta@opnsrc.net Subject: online-policy/hotplug rebase for v6.3-rc1+

Hi Salil,

I've rebased the online-policy/hotplug stuff onto Oliver's preferred way of doing PSCI in userspace. The whole tree is here: https://gitlab.arm.com/linux-arm/linux-jm/- /tree/virtual_cpu_hotplug/snapshot/20230224

I'll probably only post the in-guest parts, as the combined thing is getting too big.

Is there any chance you could update the Qemu support for this, so that folk can play with it when its next posted?

Yes, definitely. I will test all of this with Qemu and share a tested branch for this. Coming week?

For the past 2 weeks was tied up with some other stuff and leftover issues inside Qemu which are necessary to be revisited before I float RFC V2.

I've tested the KVM side of it with PSCI support for kvmtool, which is here: https://gitlab.arm.com/linux-arm/kvmtool-jm/-/tree/psci_in_userpsace/rfc/v1

Thanks.

The upshot is the CAP's disappear, and the device get/set attr has to be used against the VM fd to setup an SMC-CC filter for PSCI. Hopefully the kvmtool example makes your life easier.

Right. I did silently follow the discussion on the linux-arm-kernel. I will update the Qemu for this.

Any feedback on how easy this is for Qemu to use would be great.

Will take up this activity in the upcoming week.

I've not looked into Vishnu's bug report yet.

I have not tested it either. I will check that as well.

Thanks Salil