Re: [libvirt] [RFC] kvm: x86: export vCPU halted state to sysfs
On 02.02.2018 21:41, Eduardo Habkost wrote:
On Fri, Feb 02, 2018 at 03:19:45PM -0500, Luiz Capitulino wrote:
> On Fri, 2 Feb 2018 18:09:12 -0200
> Eduardo Habkost <ehabkost(a)redhat.com> wrote:
[...]
>> Your plan above covers what will happen when using newer QEMU
>> versions, but libvirt still needs to work sanely if running QEMU
>> 2.11. My suggestion is that libvirt do not run query-cpus to ask
>> for the "halted" field on any architecture except s390.
>
> My current plan is to ask libvirt to completely remove query-cpus
> usage, independent of the arch and use the new command instead.
This would be a regression for people running QEMU 2.11 on s390.
(But maybe it would be an acceptable regression? Viktor, what do
you think? Are there production releases of management systems
that already rely on vcpu.<n>.halted?)
Unfortunately, there's code out there looking at vcpu.<n>.halted.
I've
informed the product team about the issue.
If we drop/deprecate vcpu.<n>.halted from the domain statistics, this
should be done for all arches, if there's a replacement mechanism (i.e.
new VCPU states). As a stop-gap measure we can make the call
arch-dependent until the new stuff is in place.
BTW: libvirt cannot eliminate query-cpus entirely because initial CPU
topology and changes due to hotplug must be queried.
--
Regards,
Viktor Mihajlovski