@@ -2863,7 +2863,13 @@ static void spapr_core_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
goto out;
}
- if (cc->nr_threads != smp_threads) {
+ /*
+ * In general we should have homogeneous threads-per-core, but old
+ * (pre hotplug support) machine types allow the last core to have
+ * reduced threads as a compatibility hack for when we allowed
+ * total vcpus not a multiple of threads-per-core.
+ */
+ if (mc->has_hotpluggable_cpus && (cc->nr_threads != smp_threads)) {
error_setg(errp, "invalid nr-threads %d, must be %d",
cc->nr_threads, smp_threads);
return;