Re: [Qemu-ppc] [PATCH v2 6/7] spapr: use ppc_set_vcpu_dt_id() in CPU hotplug code

[Greg Kurz]

On Sat, 2 Jul 2016 13:44:08 +0530
Bharata B Rao <address@hidden> wrote:

> On Sat, Jul 02, 2016 at 12:42:04AM +0200, Greg Kurz wrote:
> > Starting with version 2.7, pseries machine now support hotplug of
> > cpu cores. The implementation requires to open code cpu creation
> > and thus does not call ppc_cpu_init().
> > 
> > This patch does all the plumbing to allow pseries machine types
> > with version >= 2.7 to generate cpu DT ids out of the indexes
> > of the cores and threads in their respective arrays.
> > 
> > Suggested-by: Igor Mammedov <address@hidden>
> > Signed-off-by: Greg Kurz <address@hidden>
> > ---
> >  hw/ppc/ppc.c            |    2 +-
> >  hw/ppc/spapr_cpu_core.c |   11 +++++++++--
> >  include/hw/ppc/ppc.h    |    1 +
> >  3 files changed, 11 insertions(+), 3 deletions(-)
> > 
> > diff --git a/hw/ppc/ppc.c b/hw/ppc/ppc.c
> > index dbc8ac7b3a9b..12de255fb211 100644
> > --- a/hw/ppc/ppc.c
> > +++ b/hw/ppc/ppc.c
> > @@ -1352,7 +1352,7 @@ PowerPCCPU *ppc_get_vcpu_by_dt_id(int cpu_dt_id)
> >      return NULL;
> >  }
> > 
> > -static void ppc_set_vcpu_dt_id(PowerPCCPU *cpu, int cpu_index, Error 
> > **errp)
> > +void ppc_set_vcpu_dt_id(PowerPCCPU *cpu, int cpu_index, Error **errp)
> >  {
> >      ;
> >  }
> > diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
> > index 70b6b0b5ee17..475c8063f086 100644
> > --- a/hw/ppc/spapr_cpu_core.c
> > +++ b/hw/ppc/spapr_cpu_core.c
> > @@ -259,13 +259,20 @@ out:
> >      error_propagate(errp, local_err);
> >  }
> > 
> > -static void spapr_cpu_core_realize_child(Object *child, Error **errp)
> > +static void spapr_cpu_core_realize_child(Object *child, int cpu_index,
> > +                                         Error **errp)
> >  {
> >      Error *local_err = NULL;
> >      sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
> >      CPUState *cs = CPU(child);
> >      PowerPCCPU *cpu = POWERPC_CPU(cs);
> > 
> > +    ppc_set_vcpu_dt_id(cpu, cpu_index, &local_err);
> > +    if (local_err) {
> > +        error_propagate(errp, local_err);
> > +        return;
> > +    }
> > +
> >      object_property_set_bool(child, true, "realized", &local_err);
> >      if (local_err) {
> >          error_propagate(errp, local_err);
> > @@ -306,7 +313,7 @@ static void spapr_cpu_core_realize(DeviceState *dev, 
> > Error **errp)
> >      for (j = 0; j < cc->nr_threads; j++) {
> >          obj = sc->threads + j * size;
> > 
> > -        spapr_cpu_core_realize_child(obj, &local_err);
> > +        spapr_cpu_core_realize_child(obj, cc->core_id + j, &local_err);  
> 
> cc->core_id is essentially the cpu_dt_id. For boot time cores, we set this
> (via core-id prop) explicitly. For hotplugged cores, we expect user to
> set this mandatorily on -device/device_add. The value that the
> user is expected to provide as core-id is in fact supplied by us via
> query-hotpluggable-cpus. So there are two places (ppc_spapr_init &
> spapr_query_hotpluggable_cpus) where we generate the cpu_dt_id by
> open coding as (core_index * smt). Can we have consolidate this logic
> into some well defined routine like ppc_core_index_to_dt_id() ?
> 

Sure ! I'll have a closer look.

> Regards,
> Bharata.
> 

Cheers.

--
Greg