On Sun, Aug 16, 2020 at 03:38:20PM +0200, Cédric Le Goater wrote: > On 8/16/20 6:30 AM, David Gibson wrote: > > On Fri, Aug 14, 2020 at 05:08:13PM +0200, Cédric Le Goater wrote: > >> > >> This works as expected with a 128 vCPUs guest with pinned vcpus. The > >> first 64 IPIs are allocated on the first chip and the remaining 64 > >> on the second chip. > >> > >> Still, this is more an RFC. We have time before the end of the merge > >> window. > > > > It looks reasonable to me. AFAICT it makes things better than they > > were, and even if we can improve it further, that won't break > > migration or other interfaces we need to preserve. > > Yeah. What I don't like is this test below. I am not sure that > machine->smp.cpus is the correct way to test the number of currently > active vCPUs.
Ah, yeah. It should be correct at initial startup, but might not be
after a bunch of hotplugs/unplugs, which could result in a sparse set
of active vcpus.
Usually this code will be called during initial setup, but I think
there are some edge cases where it won't be (e.g. boot a XICS kernel,
do some vcpu plugs/unplugs, reboot into a XIVE kernel).
So I think we need to explicitly check for each vcpu # if it's
currently active. Using... spapr_find_cpu(), I guess?
>
> >>> + if (srcno < machine->smp.cpus) {
> >>> + return kvmppc_xive_reset_ipi(xive, srcno, errp);
> >>> + }
> >>> +
> >>> if (xive_source_irq_is_lsi(xsrc, srcno)) {
> >>> state |= KVM_XIVE_LEVEL_SENSITIVE;
> >>> if (xsrc->status[srcno] & XIVE_STATUS_ASSERTED) {
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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