On Tue, Feb 09, 2021 at 04:25:06PM +0000, Daniel P. Berrangé wrote:
> On Tue, Feb 09, 2021 at 05:23:35PM +0100, Pavel Hrdina wrote:
> > On Tue, Feb 09, 2021 at 01:59:00PM +0000, Daniel P. Berrangé wrote:
> > > This is a special CPU model similar to "-cpu host", so won't use our
> > > normal CPU model detection logic.
> > >
> > > Signed-off-by: Daniel P. Berrangé <berrange@xxxxxxxxxx>
> > > ---
> > > src/qemu/qemu_capabilities.c | 11 +++++++++++
> > > src/qemu/qemu_capabilities.h | 1 +
> > > 2 files changed, 12 insertions(+)
> > >
> > > diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
> > > index d0378f94bc..ecfb313d0a 100644
> > > --- a/src/qemu/qemu_capabilities.c
> > > +++ b/src/qemu/qemu_capabilities.c
> > > @@ -614,6 +614,7 @@ VIR_ENUM_IMPL(virQEMUCaps,
> > >
> > > /* 390 */
> > > "vhost-user-blk",
> > > + "cpu-max",
> > > );
> > >
> > >
> > > @@ -2984,12 +2985,22 @@ virQEMUCapsProbeQMPCPUDefinitions(virQEMUCapsPtr qemuCaps,
> > > virQEMUCapsAccelPtr accel,
> > > qemuMonitorPtr mon)
> > > {
> > > + qemuMonitorCPUDefsPtr defs = accel->cpuModels;
> >
> > accel->cpuModels is NULL here ... [0]
> >
> > > + size_t i;
> > > +
> > > if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_QUERY_CPU_DEFINITIONS))
> > > return 0;
> > >
> > > if (virQEMUCapsFetchCPUDefinitions(mon, qemuCaps->arch, &accel->cpuModels) < 0)
> > > return -1;
> > >
> > > + for (i = 0; i < defs->ncpus; i++) {
> >
> > [0] ... so here it will crash.
> >
> > > + if (STREQ_NULLABLE(defs->cpus[i].name, "max")) {
> > > + virQEMUCapsSet(qemuCaps, QEMU_CAPS_CPU_MAX);
> > > + break;
> > > + }
> > > + }
> > > +
> >
> > Do we trust QEMU that if accel=kvm supports cpu-max that accel=tcg
> > supports it as well and is that true on all architectures?
>
> Yes, it would be considered a bug if that wasn't the case, because the
> whole point of "max" is that it works for KVM and TCG.
OK, in that case if you move the fix for the crash from previous patch
here
Reviewed-by: Pavel Hrdina <phrdina@xxxxxxxxxx>
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