Re: [Qemu-devel] [RFC V2 10/10] cpus: reclaim allocated vCPU objects

[Peter Maydell]

On 8 December 2014 at 09:16, Bharata B Rao <address@hidden> wrote:
> So this approach of parking the vcpu fd in QEMU and reusing it next
> time during CPU hotplug will only work if all architectures supported
> by KVM driver are ok with reuse of vcpu object in the kernel. I am
> using relevant bits of this patch of yours with PowerPC architecture
> to support cpu unplug and I realize that there is at least one case
> where reuse of vcpu object in the kernel causes problems. Before I
> attempt to fix that in ppc KVM, I wanted to check if there is
> consensus on this approach (parking and reusing kvm vcpu fd) in QEMU.

For ARM we've just clarified the kernel-to-userspace ABI, and
among other things it says you can't reuse the VCPU unless it's
for exactly the same CPU type and feature configuration. So
I'm not sure this park-and-reuse approach will work...

-- PMM