Re: [Qemu-devel] [for-2.7 PATCH v3 13/15] QMP: Add query-hotpluggable-cpus

[David Gibson <david@gibson.dropbear.id.au>]

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On Thu, May 12, 2016 at 09:18:23AM +0530, Bharata B Rao wrote:
> From: Igor Mammedov <imammedo@redhat.com>
> 
> It will allow mgmt to query present and hotpluggable CPU objects,
> it is required from a target platform that wishes to support command
> to implement and set MachineClass.query_hotpluggable_cpus callback,
> which will return a list of possible CPU objects with options that
> would be needed for hotplugging possible CPU objects.
> 
> There are:
> 'type': 'str' - QOM CPU object type for usage with device_add
> 'vcpus-count': 'int' - number of logical VCPU threads per
>                         CPU object (mgmt needs to know)
> 
> and a set of optional fields that are to used for hotplugging a CPU
> objects and would allows mgmt tools to know what/where it could be
> hotplugged;
> [node],[socket],[core],[thread]
> 
> For present CPUs there is a 'qom-path' field which would allow mgmt to
> inspect whatever object/abstraction the target platform considers
> as CPU object.
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

Igor, if you're ready for this to go ahead, I'll take it through my tree.

> ---
>  include/hw/boards.h |  5 +++++
>  monitor.c           | 13 +++++++++++++
>  qapi-schema.json    | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  qmp-commands.hx     | 23 ++++++++++++++++++++++
>  4 files changed, 96 insertions(+)
> 
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index 8d4fe56..0db0c1e 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -81,6 +81,10 @@ typedef struct {
>   *    Returns an array of @CPUArchId architecture-dependent CPU IDs
>   *    which includes CPU IDs for present and possible to hotplug CPUs.
>   *    Caller is responsible for freeing returned list.
> + * @query_hotpluggable_cpus:
> + *    Returns a @HotpluggableCPUList, which describes CPUs objects which
> + *    could be added with -device/device_add.
> + *    Caller is responsible for freeing returned list.
>   */
>  struct MachineClass {
>      /*< private >*/
> @@ -124,6 +128,7 @@ struct MachineClass {
>                                             DeviceState *dev);
>      unsigned (*cpu_index_to_socket_id)(unsigned cpu_index);
>      CPUArchIdList *(*possible_cpu_arch_ids)(MachineState *machine);
> +    HotpluggableCPUList *(*query_hotpluggable_cpus)(MachineState *machine);
>  };
>  
>  /**
> diff --git a/monitor.c b/monitor.c
> index d1c1930..b469225 100644
> --- a/monitor.c
> +++ b/monitor.c
> @@ -4267,3 +4267,16 @@ GICCapabilityList *qmp_query_gic_capabilities(Error **errp)
>      return NULL;
>  }
>  #endif
> +
> +HotpluggableCPUList *qmp_query_hotpluggable_cpus(Error **errp)
> +{
> +    MachineState *ms = MACHINE(qdev_get_machine());
> +    MachineClass *mc = MACHINE_GET_CLASS(ms);
> +
> +    if (!mc->query_hotpluggable_cpus) {
> +        error_setg(errp, QERR_FEATURE_DISABLED, "query-hotpluggable-cpus");
> +        return NULL;
> +    }
> +
> +    return mc->query_hotpluggable_cpus(ms);
> +}
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 54634c4..137e532 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -4178,3 +4178,58 @@
>  # Since: 2.6
>  ##
>  { 'command': 'query-gic-capabilities', 'returns': ['GICCapability'] }
> +
> +##
> +# CpuInstanceProperties
> +#
> +# List of properties to be used for hotplugging a CPU instance,
> +# it should be passed by management with device_add command when
> +# a CPU is being hotplugged.
> +#
> +# Note: currently there are 4 properties that could be present
> +# but management should be prepared to pass through other
> +# properties with device_add command to allow for future
> +# interface extension.
> +#
> +# @node: #optional NUMA node ID the CPU belongs to
> +# @socket: #optional socket number within node/board the CPU belongs to
> +# @core: #optional core number within socket the CPU belongs to
> +# @thread: #optional thread number within core the CPU belongs to
> +#
> +# Since: 2.7
> +##
> +{ 'struct': 'CpuInstanceProperties',
> +  'data': { '*node': 'int',
> +            '*socket': 'int',
> +            '*core': 'int',
> +            '*thread': 'int'
> +  }
> +}
> +
> +##
> +# @HotpluggableCPU
> +#
> +# @type: CPU object type for usage with device_add command
> +# @props: list of properties to be used for hotplugging CPU
> +# @vcpus-count: number of logical VCPU threads @HotpluggableCPU provides
> +# @qom-path: #optional link to existing CPU object if CPU is present or
> +#            omitted if CPU is not present.
> +#
> +# Since: 2.7
> +##
> +{ 'struct': 'HotpluggableCPU',
> +  'data': { 'type': 'str',
> +            'vcpus-count': 'int',
> +            'props': 'CpuInstanceProperties',
> +            '*qom-path': 'str'
> +          }
> +}
> +
> +##
> +# @query-hotpluggable-cpus
> +#
> +# Returns: a list of HotpluggableCPU objects.
> +#
> +# Since: 2.7
> +##
> +{ 'command': 'query-hotpluggable-cpus', 'returns': ['HotpluggableCPU'] }
> diff --git a/qmp-commands.hx b/qmp-commands.hx
> index de896a5..5640147 100644
> --- a/qmp-commands.hx
> +++ b/qmp-commands.hx
> @@ -4880,3 +4880,26 @@ Example:
>                  { "version": 3, "emulated": false, "kernel": true } ] }
>  
>  EQMP
> +
> +    {
> +        .name       = "query-hotpluggable-cpus",
> +        .args_type  = "",
> +        .mhandler.cmd_new = qmp_marshal_query_hotpluggable_cpus,
> +    },
> +
> +SQMP
> +Show existing/possible CPUs
> +---------------------------
> +
> +Arguments: None.
> +
> +Example for pseries machine type started with
> +-smp 2,cores=2,maxcpus=4 -cpu POWER8:
> +
> +-> { "execute": "query-hotpluggable-cpus" }
> +<- {"return": [
> +     { "props": { "core": 8 }, "type": "POWER8-spapr-cpu-core",
> +       "vcpus-count": 1 },
> +     { "props": { "core": 0 }, "type": "POWER8-spapr-cpu-core",
> +       "vcpus-count": 1, "qom-path": "/machine/unattached/device[0]"}
> +   ]}'

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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