On Fri, Aug 19, 2016 at 13:10:09 -0400, John Ferlan wrote:
>
>
> On 08/19/2016 10:38 AM, Peter Krempa wrote:
> > As of qemu commit:
> > commit a32ef3bfc12c8d0588f43f74dcc5280885bbdb30
> > Author: Thomas Huth <thuth@xxxxxxxxxx>
> > Date: Wed Jul 22 15:59:50 2015 +0200
> >
> > vl: Add another sanity check to smp_parse() function
> >
> > v2.4.0-952-ga32ef3b
> >
> > configuration where the maximum CPU count doesn't match the topology is
> > rejected. Prior to that only configurations where the topology would
> > contain more cpus than the maximum count would be rejected.
> >
> > Use QEMU_CAPS_QUERY_HOTPLUGGABLE_CPUS as a relevant recent enough
> > witness to avoid breaking old configs.
> > ---
> >
> > Notes:
> > v2:
> > -fixed typo in commit message
> > - already ACKed
> >
> > src/qemu/qemu_domain.c | 38 ++++++++++++++++++++++++++++++++------
> > 1 file changed, 32 insertions(+), 6 deletions(-)
[...]
> > + /* qemu as of 2.5.0 rejects SMP topologies that don't match the cpu count */
> > + if (def->cpu && def->cpu->sockets) {
> > + topologycpus = def->cpu->sockets * def->cpu->cores * def->cpu->threads;
> > + if (topologycpus != virDomainDefGetVcpusMax(def)) {
> > + /* presence of query-hotpluggable-cpus should be a good enough witness */
> > + if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_QUERY_HOTPLUGGABLE_CPUS)) {
> > + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> > + _("CPU topology doesn't match maximum vcpu count"));
> > + goto cleanup;
> > + }
>
> Would it be a good idea to add a VIR_WARN or VIR_INFO (something) that
> will give a heads up that the configuration may prevent some future
> start? Especially since you went through all the math before detecting
> the capability...
Well, adding a warning would be cerainly easy, but as it was discussed
earlier, using VIR_WARN or VIR_INFO doesn't make much sense since it's
improbable that the user will be reading logs after defining a VM.
Peter
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