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/snapsho...
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?
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
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.
Any feedback on how easy this is for Qemu to use would be great.
I've not looked into Vishnu's bug report yet.
Thanks,
James