Re: [Qemu-devel] [RFC PATCH v2 3/5] spapr: Set stable_cpu_id for threads of CPU cores

[Greg Kurz]

On Thu,  7 Jul 2016 20:20:23 +0530
Bharata B Rao <address@hidden> 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.
> 

The last sentence is a bit confusing since the enablement actually happens
in patch 5/5.

> Signed-off-by: Bharata B Rao <address@hidden>
> ---
>  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 */

It isn't what I had in mind. More something like below:

In ppc_spapr_init():

    for (i = 0; i < spapr_max_cores; i++) {
        spapr->cores[i]->stable_id = i * smp_threads;
    }


In spapr_cpu_core_realize():

    for (j = 0; j < cc->nr_threads; j++) {
        stable_cpu_id = cc->stable_id + j;
    }

So we need to introduce cc->stable_id.

I think stable_cpu_id is the prerequisite to compute both cpu_dt_id and 
instance_id.

Makes sense ?

> +        if (cs->has_stable_cpu_id) {
> +            cs->stable_cpu_id = cc->core_id + i;
> +        }
>          snprintf(id, sizeof(id), "thread[%d]", i);
>          object_property_add_child(OBJECT(sc), id, obj, &local_err);
>          if (local_err) {