Hi Salil,
On 25/01/2023 09:40, Salil Mehta wrote:
Qemu isn't responding with PSCI_DENIED when CPUs are forbidden. ('SUCCESS' means you hit a 5 second timeout in the guest, on each CPU)
I have tested the straight forward case and it works. Could you please elaborate on this so that I can look into the issue?
Sorry for the delay'd response - (I've been debugging CPU_SUSPEND and the arch-timer when using this PSCI to user-space stuff).
This test ran with a vanilla v6.1 kernel, so it doesn't have the PSCI or HVC to user-space capabilities. It looks like Qemu ignores this, and offers the policy-management/hotplug stuff anyway. The result is hitting the 5-second timeout whenever a 'denied' CPU fails to come online. This kind of thing will break migration if a guest using these features is allowed to start on a host that doesn't have them.
As we should have a list of issues, the others are:
* libvirt, "first vcpu unplug times out", reported by Russell on the 5th-Jan. (private email to you an I)
* Guest can't shutdown properly, "reboot: Power down" is displayed, but then nothing happens. Reported by Russell on the 20th-December. It looks like the mail I sent here didn't get delivered... (sorry if this one is new!)
I've had a look at the KVM code for the last one, I don't think it requires all the vCPU threads to be in the kernel. I've also been unable to reproduce it.
Thanks,
James