On Fri, Jul 08, 2016 at 03:24:13PM +1000, David Gibson wrote:
> On Thu, Jul 07, 2016 at 08:20:23PM +0530, Bharata B Rao wrote:
> > Conditonally set stable_cpu_id for CPU threads that are created as part
> > of spapr CPU cores. The use of stable_cpu_id is enabled for pseries-2.7
> > onwards.
> >
> > Signed-off-by: Bharata B Rao <bhar...@linux.vnet.ibm.com>
> > ---
> > hw/ppc/spapr_cpu_core.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
> > index b104778..0ec3513 100644
> > --- a/hw/ppc/spapr_cpu_core.c
> > +++ b/hw/ppc/spapr_cpu_core.c
> > @@ -293,8 +293,15 @@ static void spapr_cpu_core_realize(DeviceState *dev,
> > Error **errp)
> > for (i = 0; i < cc->nr_threads; i++) {
> > char id[32];
> > obj = sc->threads + i * size;
> > + CPUState *cs;
> >
> > object_initialize(obj, size, typename);
> > + cs = CPU(obj);
> > +
> > + /* Use core_id (which is actually cpu_dt_id) as stable CPU id */
> > + if (cs->has_stable_cpu_id) {
> > + cs->stable_cpu_id = cc->core_id + i;
> > + }
>
> Testing cs->has_stable_cpu_id here in machine type specific code seems
> really weird. It's the machine type that knows whether it has a
> stable ID to give to the CPU or not, rather than the other way around.
>
> Since we haven't yet had a release with cpu cores, I think the right
> thing is for cpu_core to unconditionally set the stable ID (and set
> has_stable_id to true).
Right, we can set cpu_stable_id unconditionally here since this code path
(core realize) will be taken only for pseries-2.7 onwards. has_stable_id
will get set as part of the property we defined in SPAPR_COMPAT_2_7.
> The backup path that does thread-based cpu
> init, can set has_stable_id to false (if that's not the default).
Default is off, but turning it on for 2.7 will be inherited by 2.6
and others below. Hence I have code to explicitly disable this prop
for 2.6 and below via SPAPR_COMPAT_2_6.
Regards,
Bharata.
