RE: Does "-object" support structured options now?

[Chun Feng Wu]

Thanks Daniel for your response!

I tried it with the following cmd

qemu-system-x86_64 [other options...] \

  -object '{"qom-type":"throttle-group","id":"limits0","limits":{"iops-total":200}}'

 

And I got error:
qemu-system-x86_64: -object {"qom-type":"throttle-group","id":"limits0","limits":{"iops-total":200}}: Parameter 'id' is missing

 

Do you know why such error happens?

 

-- 

Thanks and Regards,

 

Wu

 

 

From: Daniel P. Berrangé <berrange@redhat.com>
Date: Monday, March 4, 2024 at 16:06
To: Chun Feng Wu <wucf@cn.ibm.com>
Cc: qemu-devel@nongnu.org <qemu-devel@nongnu.org>
Subject: [EXTERNAL] Re: Does "-object" support structured options now?

On Mon, Mar 04, 2024 at 06:43:19AM +0000, Chun Feng Wu wrote:
> Hi,
>
> I noticed that throttle-group can be created with “-object”, however, per qemu doc(https://github.com/qemu/qemu/blob/master/docs/throttle.txt ), “-object” doesn’t support structured options at that moment:
>
> “
> A throttle-group can also be created with the -object command line
> option but at the moment there is no way to pass a 'limits' parameter
> that contains a ThrottleLimits structure. The solution is to set the
> individual values directly, like in this example:
>
>    -object throttle-group,id=group0,x-iops-total=1000,x-bps-write=2097152
>
> Note however that this is not a stable API (hence the 'x-' prefixes) and
> will disappear when -object gains support for structured options and
> enables use of 'limits'.
> “
>
> Does anybody know if the latest qemu code still lacks of such
> support(structured options for -object)? If so, is there any
> plan to support it(instead of non-stable API)?

-object supports JSON syntax these days so any QAPI structure can be
expressed no matter how complex.


With regards,
Daniel
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