[Qemu-devel] QAPI magician wanted ...

[Qemu-devel] QAPI magician wanted ...

[Igor Mammedov]

I'm working on introducing QMP command to set numa mappings
via QMP interface at runtime instead of CLI.

I'd prefer to reuse NumaOptions for parsing input,
but I can't wrap my head around QAPI magic.

So far I've added new command in qapi-schema.json:

  {
    'command': 'set-numa-node',                                                    
    'data': {'cmd': 'NumaOptions'}                                                 
  }

it at least compiles and manages to handle input without union part

  { "execute": "set-numa-node", "arguments": { "cmd": { "type": "node" } } }

however I can't figure out syntax that adds union part to it,
I have tried something like this

  { "execute": "set-numa-node", "arguments": { "cmd": { "type": "node", "node" : { "nodeid": 1 } } } }

but it errors out with

  {"error": {"class": "GenericError", "desc": "Parameter 'cmd.node' is unexpected"}}

Any advice on how to make it work if possible at all or
alternative ways how to achieve the end goal.

Re: [Qemu-devel] QAPI magician wanted ...

[Daniel P. Berrange]

On Thu, Oct 12, 2017 at 02:21:53PM +0200, Igor Mammedov wrote:
> 
> I'm working on introducing QMP command to set numa mappings
> via QMP interface at runtime instead of CLI.
> 
> I'd prefer to reuse NumaOptions for parsing input,
> but I can't wrap my head around QAPI magic.
> 
> So far I've added new command in qapi-schema.json:
> 
>   {
>     'command': 'set-numa-node',                                                    
>     'data': {'cmd': 'NumaOptions'}                                                 
>   }

I don't see any point in the extra level of nesting you have here, vs
using NumaOptions as the data directly eg

   {
     'command': 'set-numa-node',
     'data': 'NumaOptions'              
   }


> it at least compiles and manages to handle input without union part
> 
>   { "execute": "set-numa-node", "arguments": { "cmd": { "type": "node" } } }
> 
> however I can't figure out syntax that adds union part to it,
> I have tried something like this
> 
>   { "execute": "set-numa-node", "arguments": { "cmd": { "type": "node", "node" : { "nodeid": 1 } } } }
> 
> but it errors out with
> 
>   {"error": {"class": "GenericError", "desc": "Parameter 'cmd.node' is unexpected"}}
> 
> Any advice on how to make it work if possible at all or
> alternative ways how to achieve the end goal.

I think the union gets flattenned - ie you probably want

   { "execute": "set-numa-node", "arguments": { "cmd": { "type": "node", "nodeid": 1 } } }

Though with my suggestion above you could get it to just

   { "execute": "set-numa-node", "arguments": { "type": "node", "nodeid": 1 } }

Regards,
Daniel
-- 
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Re: [Qemu-devel] QAPI magician wanted ...

[Igor Mammedov]

On Thu, 12 Oct 2017 13:28:26 +0100
"Daniel P. Berrange" <berrange@redhat.com> wrote:

> On Thu, Oct 12, 2017 at 02:21:53PM +0200, Igor Mammedov wrote:
> > 
> > I'm working on introducing QMP command to set numa mappings
> > via QMP interface at runtime instead of CLI.
> > 
> > I'd prefer to reuse NumaOptions for parsing input,
> > but I can't wrap my head around QAPI magic.
> > 
> > So far I've added new command in qapi-schema.json:
> > 
> >   {
> >     'command': 'set-numa-node',                                                    
> >     'data': {'cmd': 'NumaOptions'}                                                 
> >   }  
> 
> I don't see any point in the extra level of nesting you have here, vs
> using NumaOptions as the data directly eg
> 
>    {
>      'command': 'set-numa-node',
>      'data': 'NumaOptions'              
>    }
I've tried that, it doesn't compile
   'data' for command 'set-numa-node' cannot use union type 'NumaOptions'

> 
> 
> > it at least compiles and manages to handle input without union part
> > 
> >   { "execute": "set-numa-node", "arguments": { "cmd": { "type": "node" } } }
> > 
> > however I can't figure out syntax that adds union part to it,
> > I have tried something like this
> > 
> >   { "execute": "set-numa-node", "arguments": { "cmd": { "type": "node", "node" : { "nodeid": 1 } } } }
> > 
> > but it errors out with
> > 
> >   {"error": {"class": "GenericError", "desc": "Parameter 'cmd.node' is unexpected"}}
> > 
> > Any advice on how to make it work if possible at all or
> > alternative ways how to achieve the end goal.  
> 
> I think the union gets flattenned - ie you probably want
> 
>    { "execute": "set-numa-node", "arguments": { "cmd": { "type": "node", "nodeid": 1 } } }
thanks, that works for me 

> 
> Though with my suggestion above you could get it to just
> 
>    { "execute": "set-numa-node", "arguments": { "type": "node", "nodeid": 1 } }
> 
> Regards,
> Daniel

Re: [Qemu-devel] QAPI magician wanted ...

[Eric Blake]

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On 10/12/2017 07:38 AM, Igor Mammedov wrote:
> On Thu, 12 Oct 2017 13:28:26 +0100
> "Daniel P. Berrange" <berrange@redhat.com> wrote:
> 
>> On Thu, Oct 12, 2017 at 02:21:53PM +0200, Igor Mammedov wrote:
>>>
>>> I'm working on introducing QMP command to set numa mappings
>>> via QMP interface at runtime instead of CLI.
>>>
>>> I'd prefer to reuse NumaOptions for parsing input,
>>> but I can't wrap my head around QAPI magic.
>>>
>>> So far I've added new command in qapi-schema.json:
>>>
>>>   {
>>>     'command': 'set-numa-node',                                                    
>>>     'data': {'cmd': 'NumaOptions'}                                                 
>>>   }  
>>
>> I don't see any point in the extra level of nesting you have here, vs
>> using NumaOptions as the data directly eg
>>
>>    {
>>      'command': 'set-numa-node',
>>      'data': 'NumaOptions'              
>>    }
> I've tried that, it doesn't compile
>    'data' for command 'set-numa-node' cannot use union type 'NumaOptions'

{ 'command': 'set-numa-node', 'boxed': true,
  'data': 'NumaOptions' }

To use a union directly as the command (which is a GOOD idea), you have
to tell the generator to pass it as a boxed item to the
qmp_set_numa_node function, rather than as exploded parameters, since
the generator can't explode parameters from a union..

>> I think the union gets flattenned - ie you probably want
>>
>>    { "execute": "set-numa-node", "arguments": { "cmd": { "type": "node", "nodeid": 1 } } }
> thanks, that works for me 
> 
>>
>> Though with my suggestion above you could get it to just
>>
>>    { "execute": "set-numa-node", "arguments": { "type": "node", "nodeid": 1 } }

Yes, I'd prefer this form without the extra nesting.


-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


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Re: [Qemu-devel] QAPI magician wanted ...

[Igor Mammedov]

On Thu, 12 Oct 2017 08:17:16 -0500
Eric Blake <eblake@redhat.com> wrote:

> On 10/12/2017 07:38 AM, Igor Mammedov wrote:
> > On Thu, 12 Oct 2017 13:28:26 +0100
> > "Daniel P. Berrange" <berrange@redhat.com> wrote:
> >   
> >> On Thu, Oct 12, 2017 at 02:21:53PM +0200, Igor Mammedov wrote:  
> >>>
> >>> I'm working on introducing QMP command to set numa mappings
> >>> via QMP interface at runtime instead of CLI.
> >>>
> >>> I'd prefer to reuse NumaOptions for parsing input,
> >>> but I can't wrap my head around QAPI magic.
> >>>
> >>> So far I've added new command in qapi-schema.json:
> >>>
> >>>   {
> >>>     'command': 'set-numa-node',                                                    
> >>>     'data': {'cmd': 'NumaOptions'}                                                 
> >>>   }    
> >>
> >> I don't see any point in the extra level of nesting you have here, vs
> >> using NumaOptions as the data directly eg
> >>
> >>    {
> >>      'command': 'set-numa-node',
> >>      'data': 'NumaOptions'              
> >>    }  
> > I've tried that, it doesn't compile
> >    'data' for command 'set-numa-node' cannot use union type 'NumaOptions'  
> 
> { 'command': 'set-numa-node', 'boxed': true,
>   'data': 'NumaOptions' }
> 
> To use a union directly as the command (which is a GOOD idea), you have
> to tell the generator to pass it as a boxed item to the
> qmp_set_numa_node function, rather than as exploded parameters, since
> the generator can't explode parameters from a union..
Thanks for suggestion,
it works and I don't need extra nesting anymore.


> >> I think the union gets flattenned - ie you probably want
> >>
> >>    { "execute": "set-numa-node", "arguments": { "cmd": { "type": "node", "nodeid": 1 } } }  
> > thanks, that works for me 
> >   
> >>
> >> Though with my suggestion above you could get it to just
> >>
> >>    { "execute": "set-numa-node", "arguments": { "type": "node", "nodeid": 1 } }  
> 
> Yes, I'd prefer this form without the extra nesting.
> 
>