Message ID | 20170402063802.30997-1-david@gibson.dropbear.id.au |
---|---|
State | New |
Headers | show |
On Sun, Apr 2, 2017 at 12:08 PM, David Gibson <david@gibson.dropbear.id.au> wrote: > For reasons that may be useful in future, CPU core objects, as used on the > pseries machine type have their own nr-threads property, potentially > allowing cores with different numbers of threads in the same system. > > If the user/management uses the values specified in query-hotpluggable-cpus > as they're expected to do, this will never matter in pratice. But that's > not actually enforced - it's possible to manually specify a core with > a different number of threads from that in -smp. That will confuse the > platform - most immediately, this can be used to create a CPU thread with > index above max_cpus which leads to an assertion failure in > spapr_cpu_core_realize(). > > For now, enforce that all cores must have the same, standard, number of > threads. > > Signed-off-by: David Gibson <david@gibson.dropbear.id.au> > --- > hw/ppc/spapr.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index 44c26e4..35db949 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -2790,6 +2790,12 @@ static void spapr_core_pre_plug(HotplugHandler > *hotplug_dev, DeviceState *dev, > goto out; > } > > + if (cc->nr_threads != smp_threads) { > + error_setg(errp, "invalid nr-threads %d, must be %d", > + cc->nr_threads, smp_threads); > + return; > + } > + > core_slot = spapr_find_cpu_slot(MACHINE(hotplug_dev), cc->core_id, > &index); > if (!core_slot) { > error_setg(&local_err, "core id %d out of range", cc->core_id); > Reviewed-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c index 44c26e4..35db949 100644 --- a/hw/ppc/spapr.c +++ b/hw/ppc/spapr.c @@ -2790,6 +2790,12 @@ static void spapr_core_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev, goto out; } + if (cc->nr_threads != smp_threads) { + error_setg(errp, "invalid nr-threads %d, must be %d", + cc->nr_threads, smp_threads); + return; + } + core_slot = spapr_find_cpu_slot(MACHINE(hotplug_dev), cc->core_id, &index); if (!core_slot) { error_setg(&local_err, "core id %d out of range", cc->core_id);
For reasons that may be useful in future, CPU core objects, as used on the pseries machine type have their own nr-threads property, potentially allowing cores with different numbers of threads in the same system. If the user/management uses the values specified in query-hotpluggable-cpus as they're expected to do, this will never matter in pratice. But that's not actually enforced - it's possible to manually specify a core with a different number of threads from that in -smp. That will confuse the platform - most immediately, this can be used to create a CPU thread with index above max_cpus which leads to an assertion failure in spapr_cpu_core_realize(). For now, enforce that all cores must have the same, standard, number of threads. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> --- hw/ppc/spapr.c | 6 ++++++ 1 file changed, 6 insertions(+)