Patchwork [2/4] QMP: add cpu-add command

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Submitter Igor Mammedov
Date April 30, 2013, 6:34 a.m.
Message ID <1367303643-16036-3-git-send-email-imammedo@redhat.com>
Download mbox | patch
Permalink /patch/240555/
State New
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Comments

Igor Mammedov - April 30, 2013, 6:34 a.m.
Adds "cpu-add id=xxx" QMP command.

cpu-add's "id" argument is a CPU number in a range [0..max-cpus)

Example QMP command:
 -> { "execute": "cpu-add", "arguments": { "id": 2 } }
 <- { "return": {} }

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
v7:
  * added "Since 1.5" to cpu-add qapi schema definition
v6:
  * added valid values description to qapi schema
  * split out cpu_hot_add hooks introduction into separate patch
  * split out implementation of cpu_hot_add for target-i386
v5:
  * accept id=[0..max_cpus) range in cpu-add command
v4:
  * merge "qmp: add cpu-add qmp command" & "target-i386: implement CPU hot-add" patches
  * move notifier call to CPUCLass.realize()
  * add hook cpu_hot_add to QEMUMachine
  * make QEMUMachineInitArgs global and keep default cpu_model there

v3:
  * it appears that 'online/offline' in cpu-set are confusing people
    with what command actually does and users might have to distinguish
    if 'offline' is not implemented by parsing error message. To simplify
    things replace cpu-set with cpu-add command to show more clear what
    command does and just add cpu-del when CPU remove is implemented.

v2:
  * s/cpu_set/cpu-set/
  * qmp doc style fix
  * use bool type instead of opencodding online/offline string
     suggested-by: Eric Blake <eblake@redhat.com>
---
 qapi-schema.json | 13 +++++++++++++
 qmp-commands.hx  | 23 +++++++++++++++++++++++
 qmp.c            | 10 ++++++++++
 3 files changed, 46 insertions(+)
Eduardo Habkost - April 30, 2013, 1:46 p.m.
(CCing libvir-list)

On Tue, Apr 30, 2013 at 08:34:01AM +0200, Igor Mammedov wrote:
> Adds "cpu-add id=xxx" QMP command.
> 
> cpu-add's "id" argument is a CPU number in a range [0..max-cpus)
> 
> Example QMP command:
>  -> { "execute": "cpu-add", "arguments": { "id": 2 } }
>  <- { "return": {} }
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> Acked-by: Luiz Capitulino <lcapitulino@redhat.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>

The only way to find out if CPU hotplug is really available on a given
machine-type is by actually trying to run cpu-add, right? Is this
sufficient for libvirt requirements?


> ---
> v7:
>   * added "Since 1.5" to cpu-add qapi schema definition
> v6:
>   * added valid values description to qapi schema
>   * split out cpu_hot_add hooks introduction into separate patch
>   * split out implementation of cpu_hot_add for target-i386
> v5:
>   * accept id=[0..max_cpus) range in cpu-add command
> v4:
>   * merge "qmp: add cpu-add qmp command" & "target-i386: implement CPU hot-add" patches
>   * move notifier call to CPUCLass.realize()
>   * add hook cpu_hot_add to QEMUMachine
>   * make QEMUMachineInitArgs global and keep default cpu_model there
> 
> v3:
>   * it appears that 'online/offline' in cpu-set are confusing people
>     with what command actually does and users might have to distinguish
>     if 'offline' is not implemented by parsing error message. To simplify
>     things replace cpu-set with cpu-add command to show more clear what
>     command does and just add cpu-del when CPU remove is implemented.
> 
> v2:
>   * s/cpu_set/cpu-set/
>   * qmp doc style fix
>   * use bool type instead of opencodding online/offline string
>      suggested-by: Eric Blake <eblake@redhat.com>
> ---
>  qapi-schema.json | 13 +++++++++++++
>  qmp-commands.hx  | 23 +++++++++++++++++++++++
>  qmp.c            | 10 ++++++++++
>  3 files changed, 46 insertions(+)
> 
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 5b0fb3b..6f58b0f 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -1387,6 +1387,19 @@
>  { 'command': 'cpu', 'data': {'index': 'int'} }
>  
>  ##
> +# @cpu-add
> +#
> +# Adds CPU with specified ID
> +#
> +# @id: ID of CPU to be created, valid values [0..max_cpus)
> +#
> +# Returns: Nothing on success
> +#
> +# Since 1.5
> +##
> +{ 'command': 'cpu-add', 'data': {'id': 'int'} }
> +
> +##
>  # @memsave:
>  #
>  # Save a portion of guest memory to a file.
> diff --git a/qmp-commands.hx b/qmp-commands.hx
> index 0e89132..ed99eb8 100644
> --- a/qmp-commands.hx
> +++ b/qmp-commands.hx
> @@ -385,6 +385,29 @@ Note: CPUs' indexes are obtained with the 'query-cpus' command.
>  EQMP
>  
>      {
> +        .name       = "cpu-add",
> +        .args_type  = "id:i",
> +        .mhandler.cmd_new = qmp_marshal_input_cpu_add,
> +    },
> +
> +SQMP
> +cpu-add
> +-------
> +
> +Adds virtual cpu
> +
> +Arguments:
> +
> +- "id": cpu id (json-int)
> +
> +Example:
> +
> +-> { "execute": "cpu-add", "arguments": { "id": 2 } }
> +<- { "return": {} }
> +
> +EQMP
> +
> +    {
>          .name       = "memsave",
>          .args_type  = "val:l,size:i,filename:s,cpu:i?",
>          .mhandler.cmd_new = qmp_marshal_input_memsave,
> diff --git a/qmp.c b/qmp.c
> index ed6c7ef..dd34be6 100644
> --- a/qmp.c
> +++ b/qmp.c
> @@ -24,6 +24,7 @@
>  #include "hw/qdev.h"
>  #include "sysemu/blockdev.h"
>  #include "qom/qom-qobject.h"
> +#include "hw/boards.h"
>  
>  NameInfo *qmp_query_name(Error **errp)
>  {
> @@ -108,6 +109,15 @@ void qmp_cpu(int64_t index, Error **errp)
>      /* Just do nothing */
>  }
>  
> +void qmp_cpu_add(int64_t id, Error **errp)
> +{
> +    if (current_machine->hot_add_cpu) {
> +        current_machine->hot_add_cpu(id, errp);
> +    } else {
> +        error_setg(errp, "Not supported");
> +    }
> +}
> +
>  #ifndef CONFIG_VNC
>  /* If VNC support is enabled, the "true" query-vnc command is
>     defined in the VNC subsystem */
> -- 
> 1.8.2.1
>
Peter Krempa - April 30, 2013, 1:53 p.m.
On 04/30/13 15:46, Eduardo Habkost wrote:
> (CCing libvir-list)
>
> On Tue, Apr 30, 2013 at 08:34:01AM +0200, Igor Mammedov wrote:
>> Adds "cpu-add id=xxx" QMP command.
>>
>> cpu-add's "id" argument is a CPU number in a range [0..max-cpus)
>>
>> Example QMP command:
>>   -> { "execute": "cpu-add", "arguments": { "id": 2 } }
>>   <- { "return": {} }
>>
>> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
>> Acked-by: Luiz Capitulino <lcapitulino@redhat.com>
>> Reviewed-by: Eric Blake <eblake@redhat.com>
>
> The only way to find out if CPU hotplug is really available on a given
> machine-type is by actually trying to run cpu-add, right? Is this
> sufficient for libvirt requirements?
>
>


As long as the command fails when it's not supported it's okay.

(cpu_set HMP command does not fail when offlining a cpu even if it isn't 
supported and that's real pain to use)

Peter
Igor Mammedov - April 30, 2013, 1:56 p.m.
On Tue, 30 Apr 2013 10:46:20 -0300
Eduardo Habkost <ehabkost@redhat.com> wrote:

> (CCing libvir-list)
> 
> On Tue, Apr 30, 2013 at 08:34:01AM +0200, Igor Mammedov wrote:
> > Adds "cpu-add id=xxx" QMP command.
> > 
> > cpu-add's "id" argument is a CPU number in a range [0..max-cpus)
> > 
> > Example QMP command:
> >  -> { "execute": "cpu-add", "arguments": { "id": 2 } }
> >  <- { "return": {} }
> > 
> > Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> > Acked-by: Luiz Capitulino <lcapitulino@redhat.com>
> > Reviewed-by: Eric Blake <eblake@redhat.com>
> 
> The only way to find out if CPU hotplug is really available on a given
> machine-type is by actually trying to run cpu-add, right? Is this
> sufficient for libvirt requirements?
yes, for now it is the only way.it was acked from their side.

> 
> 
> > ---
> > v7:
> >   * added "Since 1.5" to cpu-add qapi schema definition
> > v6:
> >   * added valid values description to qapi schema
> >   * split out cpu_hot_add hooks introduction into separate patch
> >   * split out implementation of cpu_hot_add for target-i386
> > v5:
> >   * accept id=[0..max_cpus) range in cpu-add command
> > v4:
> >   * merge "qmp: add cpu-add qmp command" & "target-i386: implement CPU hot-add" patches
> >   * move notifier call to CPUCLass.realize()
> >   * add hook cpu_hot_add to QEMUMachine
> >   * make QEMUMachineInitArgs global and keep default cpu_model there
> > 
> > v3:
> >   * it appears that 'online/offline' in cpu-set are confusing people
> >     with what command actually does and users might have to distinguish
> >     if 'offline' is not implemented by parsing error message. To simplify
> >     things replace cpu-set with cpu-add command to show more clear what
> >     command does and just add cpu-del when CPU remove is implemented.
> > 
> > v2:
> >   * s/cpu_set/cpu-set/
> >   * qmp doc style fix
> >   * use bool type instead of opencodding online/offline string
> >      suggested-by: Eric Blake <eblake@redhat.com>
> > ---
> >  qapi-schema.json | 13 +++++++++++++
> >  qmp-commands.hx  | 23 +++++++++++++++++++++++
> >  qmp.c            | 10 ++++++++++
> >  3 files changed, 46 insertions(+)
> > 
> > diff --git a/qapi-schema.json b/qapi-schema.json
> > index 5b0fb3b..6f58b0f 100644
> > --- a/qapi-schema.json
> > +++ b/qapi-schema.json
> > @@ -1387,6 +1387,19 @@
> >  { 'command': 'cpu', 'data': {'index': 'int'} }
> >  
> >  ##
> > +# @cpu-add
> > +#
> > +# Adds CPU with specified ID
> > +#
> > +# @id: ID of CPU to be created, valid values [0..max_cpus)
> > +#
> > +# Returns: Nothing on success
> > +#
> > +# Since 1.5
> > +##
> > +{ 'command': 'cpu-add', 'data': {'id': 'int'} }
> > +
> > +##
> >  # @memsave:
> >  #
> >  # Save a portion of guest memory to a file.
> > diff --git a/qmp-commands.hx b/qmp-commands.hx
> > index 0e89132..ed99eb8 100644
> > --- a/qmp-commands.hx
> > +++ b/qmp-commands.hx
> > @@ -385,6 +385,29 @@ Note: CPUs' indexes are obtained with the 'query-cpus' command.
> >  EQMP
> >  
> >      {
> > +        .name       = "cpu-add",
> > +        .args_type  = "id:i",
> > +        .mhandler.cmd_new = qmp_marshal_input_cpu_add,
> > +    },
> > +
> > +SQMP
> > +cpu-add
> > +-------
> > +
> > +Adds virtual cpu
> > +
> > +Arguments:
> > +
> > +- "id": cpu id (json-int)
> > +
> > +Example:
> > +
> > +-> { "execute": "cpu-add", "arguments": { "id": 2 } }
> > +<- { "return": {} }
> > +
> > +EQMP
> > +
> > +    {
> >          .name       = "memsave",
> >          .args_type  = "val:l,size:i,filename:s,cpu:i?",
> >          .mhandler.cmd_new = qmp_marshal_input_memsave,
> > diff --git a/qmp.c b/qmp.c
> > index ed6c7ef..dd34be6 100644
> > --- a/qmp.c
> > +++ b/qmp.c
> > @@ -24,6 +24,7 @@
> >  #include "hw/qdev.h"
> >  #include "sysemu/blockdev.h"
> >  #include "qom/qom-qobject.h"
> > +#include "hw/boards.h"
> >  
> >  NameInfo *qmp_query_name(Error **errp)
> >  {
> > @@ -108,6 +109,15 @@ void qmp_cpu(int64_t index, Error **errp)
> >      /* Just do nothing */
> >  }
> >  
> > +void qmp_cpu_add(int64_t id, Error **errp)
> > +{
> > +    if (current_machine->hot_add_cpu) {
> > +        current_machine->hot_add_cpu(id, errp);
> > +    } else {
> > +        error_setg(errp, "Not supported");
> > +    }
> > +}
> > +
> >  #ifndef CONFIG_VNC
> >  /* If VNC support is enabled, the "true" query-vnc command is
> >     defined in the VNC subsystem */
> > -- 
> > 1.8.2.1
> > 
>

Patch

diff --git a/qapi-schema.json b/qapi-schema.json
index 5b0fb3b..6f58b0f 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1387,6 +1387,19 @@ 
 { 'command': 'cpu', 'data': {'index': 'int'} }
 
 ##
+# @cpu-add
+#
+# Adds CPU with specified ID
+#
+# @id: ID of CPU to be created, valid values [0..max_cpus)
+#
+# Returns: Nothing on success
+#
+# Since 1.5
+##
+{ 'command': 'cpu-add', 'data': {'id': 'int'} }
+
+##
 # @memsave:
 #
 # Save a portion of guest memory to a file.
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 0e89132..ed99eb8 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -385,6 +385,29 @@  Note: CPUs' indexes are obtained with the 'query-cpus' command.
 EQMP
 
     {
+        .name       = "cpu-add",
+        .args_type  = "id:i",
+        .mhandler.cmd_new = qmp_marshal_input_cpu_add,
+    },
+
+SQMP
+cpu-add
+-------
+
+Adds virtual cpu
+
+Arguments:
+
+- "id": cpu id (json-int)
+
+Example:
+
+-> { "execute": "cpu-add", "arguments": { "id": 2 } }
+<- { "return": {} }
+
+EQMP
+
+    {
         .name       = "memsave",
         .args_type  = "val:l,size:i,filename:s,cpu:i?",
         .mhandler.cmd_new = qmp_marshal_input_memsave,
diff --git a/qmp.c b/qmp.c
index ed6c7ef..dd34be6 100644
--- a/qmp.c
+++ b/qmp.c
@@ -24,6 +24,7 @@ 
 #include "hw/qdev.h"
 #include "sysemu/blockdev.h"
 #include "qom/qom-qobject.h"
+#include "hw/boards.h"
 
 NameInfo *qmp_query_name(Error **errp)
 {
@@ -108,6 +109,15 @@  void qmp_cpu(int64_t index, Error **errp)
     /* Just do nothing */
 }
 
+void qmp_cpu_add(int64_t id, Error **errp)
+{
+    if (current_machine->hot_add_cpu) {
+        current_machine->hot_add_cpu(id, errp);
+    } else {
+        error_setg(errp, "Not supported");
+    }
+}
+
 #ifndef CONFIG_VNC
 /* If VNC support is enabled, the "true" query-vnc command is
    defined in the VNC subsystem */