Re: [Qemu-devel] [PATCH] Introduce query-cpu-max QMP command and cpu_max HMP counterpart

[Luiz Capitulino <lcapitulino@redhat.com>]

On Tue, 12 Mar 2013 17:03:31 +0100
Michal Novotny <minovotn@redhat.com> wrote:

> This is the patch to introduce the query-cpu-max QMP command to get
> the maximum number of CPUs supported by the currently running emulator
> instance. This may differ machine from machine as defined by -machine
> settings and max_cpus member of QEMUMachine structure.
> 
> It's been tested both using QMP/qmp utility and telnet session on
> the QEMU session.

Patch looks good, but it doesn't build. See below.

> 
> The HMP counterpart called cpu_max has been introduced by this patch
> too.
> 
> Signed-off-by: Michal Novotny <minovotn@redhat.com>
> ---
>  hmp-commands.hx  | 14 ++++++++++++++
>  hmp.c            | 15 +++++++++++++++
>  hmp.h            |  1 +
>  qapi-schema.json | 11 +++++++++++
>  qmp-commands.hx  | 22 ++++++++++++++++++++++
>  vl.c             |  5 +++++
>  6 files changed, 68 insertions(+)
> 
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index 69c707d..b1224e3 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -690,6 +690,20 @@ Set the default CPU.
>  ETEXI
>  
>      {
> +        .name       = "cpu_max",
> +        .args_type  = "",
> +        .params     = "",
> +        .help       = "Get maximum number of VCPUs supported by machine",
> +        .mhandler.cmd = hmp_query_cpu_max,
> +    },
> +
> +STEXI
> +@item cpu_max
> +@findex cpu_max
> +Returns the number of CPUs supported by the machine being emulated.
> +ETEXI
> +
> +    {
>          .name       = "mouse_move",
>          .args_type  = "dx_str:s,dy_str:s,dz_str:s?",
>          .params     = "dx dy [dz]",
> diff --git a/hmp.c b/hmp.c
> index 2f47a8a..742f5c7 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -704,6 +704,21 @@ void hmp_ringbuf_read(Monitor *mon, const QDict *qdict)
>      g_free(data);
>  }
>  
> +void hmp_query_cpu_max(Monitor *mon, const QDict *qdict)
> +{
> +    int cpu_max;
> +    Error *errp = NULL;
> +
> +    cpu_max = qmp_query_cpu_max(&errp);
> +    if (errp) {
> +        monitor_printf(mon, "%s\n", error_get_pretty(errp));
> +        error_free(errp);
> +        return;
> +    }
> +
> +    monitor_printf(mon, "Maximum number of CPUs is %d\n", cpu_max);
> +}
> +
>  static void hmp_cont_cb(void *opaque, int err)
>  {
>      if (!err) {
> diff --git a/hmp.h b/hmp.h
> index 30b3c20..f0c3352 100644
> --- a/hmp.h
> +++ b/hmp.h
> @@ -41,6 +41,7 @@ void hmp_stop(Monitor *mon, const QDict *qdict);
>  void hmp_system_reset(Monitor *mon, const QDict *qdict);
>  void hmp_system_powerdown(Monitor *mon, const QDict *qdict);
>  void hmp_cpu(Monitor *mon, const QDict *qdict);
> +void hmp_query_cpu_max(Monitor *mon, const QDict *qdict);
>  void hmp_memsave(Monitor *mon, const QDict *qdict);
>  void hmp_pmemsave(Monitor *mon, const QDict *qdict);
>  void hmp_ringbuf_write(Monitor *mon, const QDict *qdict);
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 28b070f..e828839 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -1832,6 +1832,17 @@
>  { 'command': 'query-migrate-cache-size', 'returns': 'int' }
>  
>  ##
> +## @query-cpu-max
> +##
> +## query maximum number of CPUs supported by machine
> +##
> +## Returns: number of CPUs
> +##
> +## Since: 1.5
> +###
> +{ 'command': 'query-cpu-max', 'returns': 'int' }
> +
> +##
>  # @ObjectPropertyInfo:
>  #
>  # @name: the name of the property
> diff --git a/qmp-commands.hx b/qmp-commands.hx
> index 95022e2..d29de4b 100644
> --- a/qmp-commands.hx
> +++ b/qmp-commands.hx
> @@ -385,6 +385,28 @@ Note: CPUs' indexes are obtained with the 'query-cpus' command.
>  EQMP
>  
>      {
> +        .name       = "query-cpu-max",
> +        .args_type  = "",
> +        .mhandler.cmd_new = qmp_marshal_input_query_cpu_max,
> +    },
> +
> +SQMP
> +query-cpu-max
> +-------------
> +
> +Get the maximum CPUs supported by the machine being currently
> +emulated.
> +
> +Returns json-int.
> +
> +Example:
> +
> +-> { "execute": "query-cpu-max" }
> +<- { "return": 255 }
> +
> +EQMP
> +
> +    {
>          .name       = "memsave",
>          .args_type  = "val:l,size:i,filename:s,cpu:i?",
>          .mhandler.cmd_new = qmp_marshal_input_memsave,
> diff --git a/vl.c b/vl.c
> index 154f7ba..e04feb0 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -632,6 +632,11 @@ StatusInfo *qmp_query_status(Error **errp)
>      return info;
>  }
>  
> +int qmp_query_cpu_max(Error **errp)

This should be int64_t, otherwise:

/home/lcapitulino/work/src/upstream/qmp-unstable/vl.c:665:5: error: conflicting types for ‘qmp_query_cpu_max’
In file included from /home/lcapitulino/work/src/upstream/qmp-unstable/vl.c:151:0:
./qmp-commands.h:117:9: note: previous declaration of ‘qmp_query_cpu_max’ was here
make: *** [vl.o] Error 1
make: *** Waiting for unfinished jobs....

I wonder why you didn't get this.

Also, as you'll respin, please fix the log message as asked by Markus and
CC us :)

> +{
> +    return current_machine->max_cpus;
> +}
> +
>  /***********************************************************/
>  /* real time host monotonic timer */
>