Re: [Qemu-devel] [RFC v3 2/2] spapr: implement query-hotpluggable-cpus QMP command

[Bharata B Rao <bharata@linux.vnet.ibm.com>]

On Tue, Mar 15, 2016 at 02:24:08PM +0100, Igor Mammedov wrote:
> it returns a list of present/possible to hotplug CPU
> objects with a list of properties to use with
> device_add.
> 
> in spapr case returned list would looks like:
> -> { "execute": "query-hotpluggable-cpus" }
> <- {"return": [
>      { "props": { "core": 1 }, "type": "spapr-cpu-core",
>        "vcpus-count": 2 },
>      { "props": { "core": 0 }, "type": "spapr-cpu-core",
>        "vcpus-count": 2,
>        "qom-path": "/machine/unattached/device[0]"}
>    ]}'
> 
> TODO:
>   add 'node' property for core <-> numa node mapping
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> ---
> it's only compile tested
> ---
>  hw/ppc/spapr.c | 32 ++++++++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index b1e9ba2..e1ce983 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -65,6 +65,7 @@
>  #include "hw/compat.h"
>  #include "qemu-common.h"
>  #include "hw/ppc/spapr_cpu_core.h"
> +#include "qmp-commands.h"
> 
>  #include <libfdt.h>
> 
> @@ -2399,6 +2400,37 @@ static unsigned spapr_cpu_index_to_socket_id(unsigned cpu_index)
>      return cpu_index / smp_threads / smp_cores;
>  }
> 
> +HotpluggableCPUList *qmp_query_hotpluggable_cpus(Error **errp)
> +{
> +    int i;
> +    HotpluggableCPUList *head = NULL;
> +    sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
> +    int spapr_max_cores = max_cpus / smp_threads;
> +
> +    for (i = 0; i < spapr_max_cores; i++) {
> +        HotpluggableCPUList *list_item = g_new0(typeof(*list_item), 1);
> +        HotpluggableCPU *cpu_item = g_new0(typeof(*cpu_item), 1);
> +        CpuInstanceProperties *cpu_props = g_new0(typeof(*cpu_props), 1);
> +
> +        cpu_item->type = g_strdup(TYPE_SPAPR_CPU_CORE);
> +        cpu_item->vcpus_count = smp_threads;

Shouldn't this be fetched from "threads" property of the core device
instead of directly using smp_threads ? But again, what that would mean
for not-yet-plugged in cores and how to get that for them is a question.

Regards,
Bharata.