[libvirt] [PATCH v2 07/23] qemu: monitor: Add support for calling query-hotpluggable-cpus

[John Ferlan]

On 08/19/2016 10:38 AM, Peter Krempa wrote:
> Add support for retrieving information regarding hotpluggable cpu units
> supported by qemu. Data returned by the command carries information
> needed to figure out the granularity of hotplug, the necessary cpu type
> name and the topology information.
> 
> Note that qemu doesn't specify any particular order of the entries thus
> it's necessary sort them by socket_id, core_id and thread_id to the
> order libvirt expects.
> ---
> 
> Notes:
>     v2:
>     - fixed alias string in comment
>     - already ACKed
> 
>  src/qemu/qemu_monitor.h      |  16 ++++
>  src/qemu/qemu_monitor_json.c | 170 +++++++++++++++++++++++++++++++++++++++++++
>  src/qemu/qemu_monitor_json.h |   5 ++
>  3 files changed, 191 insertions(+)
> 

[...]

> +
> +/**
> + * [{
> + *    "props": {
> + *      "core-id": 0,
> + *      "thread-id": 0,
> + *      "socket-id": 0
> + *    },
> + *    "vcpus-count": 1,
> + *    "qom-path": "/machine/unattached/device[0]",
> + *    "type": "qemu64-x86_64-cpu"
> + *  },
> + *  {...}
> + * ]
> + */
> +static int
> +qemuMonitorJSONProcessHotpluggableCpusReply(virJSONValuePtr vcpu,
> +                                            struct qemuMonitorQueryHotpluggableCpusEntry *entry)
> +{
> +    virJSONValuePtr props;
> +    const char *tmp;
> +
> +    if (!(tmp = virJSONValueObjectGetString(vcpu, "type"))) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       _("query-hotpluggable-cpus didn't return device type"));
> +        return -1;
> +    }
> +
> +    if (VIR_STRDUP(entry->type, tmp) < 0)
> +        return -1;
> +
> +    if (virJSONValueObjectGetNumberUint(vcpu, "vcpus-count", &entry->vcpus) < 0) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       _("query-hotpluggable-cpus didn't return vcpus-count"));
> +        return -1;
> +    }
> +
> +    if (!(props = virJSONValueObjectGetObject(vcpu, "props"))) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       _("query-hotpluggable-cpus didn't return device props"));
> +        return -1;
> +    }
> +
> +    entry->node_id = -1;
> +    entry->socket_id = -1;
> +    entry->core_id = -1;
> +    entry->thread_id = -1;
> +
> +    ignore_value(virJSONValueObjectGetNumberInt(props, "node-id", &entry->node_id));
> +    ignore_value(virJSONValueObjectGetNumberInt(props, "socket-id", &entry->socket_id));
> +    ignore_value(virJSONValueObjectGetNumberInt(props, "core-id", &entry->core_id));
> +    ignore_value(virJSONValueObjectGetNumberInt(props, "thread-id", &entry->thread_id));
> +
> +    if (entry->node_id == -1 && entry->socket_id == -1 &&
> +        entry->core_id == -1 && entry->thread_id == -1) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       _("query-hotpluggable-cpus entry doesn't report "
> +                         "topology information"));
> +        return -1;
> +    }
> +
> +    /* qom path is not present unless the vCPU is online */
> +    if ((tmp = virJSONValueObjectGetString(vcpu, "qom-path"))) {
> +        if (VIR_STRDUP(entry->qom_path, tmp) < 0)
> +            return -1;
> +
> +        /* alias is the part after last slash having a "vcpu" prefix */
> +        if ((tmp = strrchr(tmp, '/')) && STRPREFIX(tmp + 1, "vcpu")) {
> +            if (VIR_STRDUP(entry->alias, tmp + 1) < 0)
> +                return -1;

Hmm... Just trying to understand... The example above has:

    "qom-path": "/machine/unattached/device[0]",

So "/vcpuX" shows up when?

IOW: How does an entry look that has that vcpu string in it?

Ah - I see a couple patches later in the tests:

qom_path='/machine/peripheral/vcpu0'

I was also wondering why you extract this, but I see in later patches...


John

> +        }
> +    }
> +
> +    return 0;
> +}
> +
> +

[...]