Re: [Qemu-devel] [PATCH v5 18/22] s390x: implement query-hotpluggable-cpus

[Igor Mammedov]

On Wed, 13 Sep 2017 15:24:13 +0200
David Hildenbrand <address@hidden> wrote:

> CPU hotplug is only possible on a per core basis on s390x. So let's
> add possible_cpus and properly wire everything up.
> 
> Signed-off-by: David Hildenbrand <address@hidden>
looks good to me from cpu hotplug infrastructure pov,

Acked-by: Igor Mammedov <address@hidden>

> ---
>  hw/s390x/s390-virtio-ccw.c | 41 +++++++++++++++++++++++++++++++++++++++++
>  qapi-schema.json           | 16 ++++++++++++++++
>  2 files changed, 57 insertions(+)
> 
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index 3be81d96af..cc64a81321 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -50,6 +50,7 @@ S390CPU *s390_cpu_addr2state(uint16_t cpu_addr)
>  
>  static void s390_init_cpus(MachineState *machine)
>  {
> +    MachineClass *mc = MACHINE_GET_CLASS(machine);
>      int i;
>      gchar *name;
>  
> @@ -74,6 +75,9 @@ static void s390_init_cpus(MachineState *machine)
>          g_free(name);
>      }
>  
> +    /* initialize possible_cpus */
> +    mc->possible_cpu_arch_ids(machine);
> +
>      for (i = 0; i < smp_cpus; i++) {
>          s390x_new_cpu(machine->cpu_model, i, &error_fatal);
>      }
> @@ -307,6 +311,7 @@ static void s390_cpu_plug(HotplugHandler *hotplug_dev,
>                          DeviceState *dev, Error **errp)
>  {
>      gchar *name;
> +    MachineState *ms = MACHINE(hotplug_dev);
>      S390CPU *cpu = S390_CPU(dev);
>      CPUState *cs = CPU(dev);
>  
> @@ -314,6 +319,9 @@ static void s390_cpu_plug(HotplugHandler *hotplug_dev,
>      object_property_set_link(OBJECT(hotplug_dev), OBJECT(cs), name,
>                               errp);
>      g_free(name);
> +
> +    g_assert(!ms->possible_cpus->cpus[cpu->env.core_id].cpu);
> +    ms->possible_cpus->cpus[cpu->env.core_id].cpu = OBJECT(dev);
>  }
>  
>  static void s390_machine_reset(void)
> @@ -346,6 +354,36 @@ static void 
> s390_machine_device_unplug_request(HotplugHandler *hotplug_dev,
>      }
>  }
>  
> +static CpuInstanceProperties s390_cpu_index_to_props(MachineState *machine,
> +                                                     unsigned cpu_index)
> +{
> +    g_assert(machine->possible_cpus && cpu_index < 
> machine->possible_cpus->len);
> +
> +    return machine->possible_cpus->cpus[cpu_index].props;
> +}
> +
> +static const CPUArchIdList *s390_possible_cpu_arch_ids(MachineState *ms)
> +{
> +    int i;
> +
> +    if (ms->possible_cpus) {
> +        g_assert(ms->possible_cpus && ms->possible_cpus->len == max_cpus);
> +        return ms->possible_cpus;
> +    }
> +
> +    ms->possible_cpus = g_malloc0(sizeof(CPUArchIdList) +
> +                                  sizeof(CPUArchId) * max_cpus);
> +    ms->possible_cpus->len = max_cpus;
> +    for (i = 0; i < ms->possible_cpus->len; i++) {
> +        ms->possible_cpus->cpus[i].vcpus_count = 1;
> +        ms->possible_cpus->cpus[i].arch_id = i;
> +        ms->possible_cpus->cpus[i].props.has_core_id = true;
> +        ms->possible_cpus->cpus[i].props.core_id = i;
> +    }
> +
> +    return ms->possible_cpus;
> +}
> +
>  static HotplugHandler *s390_get_hotplug_handler(MachineState *machine,
>                                                  DeviceState *dev)
>  {
> @@ -393,7 +431,10 @@ static void ccw_machine_class_init(ObjectClass *oc, void 
> *data)
>      mc->no_sdcard = 1;
>      mc->use_sclp = 1;
>      mc->max_cpus = 248;
> +    mc->has_hotpluggable_cpus = true;
>      mc->get_hotplug_handler = s390_get_hotplug_handler;
> +    mc->cpu_index_to_instance_props = s390_cpu_index_to_props;
> +    mc->possible_cpu_arch_ids = s390_possible_cpu_arch_ids;
>      hc->plug = s390_machine_device_plug;
>      hc->unplug_request = s390_machine_device_unplug_request;
>      nc->nmi_monitor_handler = s390_nmi;
> diff --git a/qapi-schema.json b/qapi-schema.json
> index f3af2cb851..79e9f85404 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -3121,6 +3121,22 @@
>  #      }
>  #    ]}
>  #
> +# For s390x-virtio-ccw machine type started with -smp 1,maxcpus=2 -cpu qemu
> +# (Since: 2.11):
> +#
> +# -> { "execute": "query-hotpluggable-cpus" }
> +# <- {"return": [
> +#      {
> +#         "type": "qemu-s390-cpu", "vcpus-count": 1,
> +#         "props": { "core-id": 1 }
> +#      },
> +#      {
> +#         "qom-path": "/machine/unattached/device[0]",
> +#         "type": "qemu-s390-cpu", "vcpus-count": 1,
> +#         "props": { "core-id": 0 }
> +#      }
> +#    ]}
> +#
>  ##
>  { 'command': 'query-hotpluggable-cpus', 'returns': ['HotpluggableCPU'] }
>