On Sun, Apr 2, 2017 at 12:08 PM, David Gibson <da...@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 <da...@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 <bhar...@linux.vnet.ibm.com>
