Re: [PATCH 08/11] mos6522: add "info via" HMP command for debugging

["Daniel P. Berrangé" <berrange@redhat.com>]

On Tue, Feb 08, 2022 at 01:06:59PM +0000, Mark Cave-Ayland wrote:
> On 08/02/2022 12:49, Daniel P. Berrangé wrote:
> 
> > > I was under the impression that monitor_register_hmp_info_hrt() does all the
> > > magic here i.e. it declares the underlying QMP command with an x- prefix and
> > > effectively encapsulates the text field in a way that says "this is an
> > > unreliable text opaque for humans"?
> > 
> > The monitor_register_hmp_info_hrt only does the HMP glue side, and
> > that's only needed if you must dynamically register the HMP command.
> > For statically registered commands set '.cmd_info_hrt' directly in
> > the hml-commands-info.hx for the HMP side.
> > 
> > > If a qapi/ schema is needed could you explain what it should look like for
> > > this example and where it should go? Looking at the existing .json files I
> > > can't immediately see one which is the right place for this to live.
> > 
> > Take a look in qapi/machine.json for anyof the 'x-query-XXXX' commands
> > there. The QAPI bit is fairly simple.
> > 
> > if you want to see an illustration of what's different from a previous
> > pure HMP impl, look at:
> > 
> >    commit dd98234c059e6bdb05a52998270df6d3d990332e
> >    Author: Daniel P. Berrangé <berrange@redhat.com>
> >    Date:   Wed Sep 8 10:35:43 2021 +0100
> > 
> >      qapi: introduce x-query-roms QMP command
> 
> I see, thanks for the reference. So qapi/machine.json would be the right
> place to declare the QMP part even for a specific device?
> 
> Even this approach still wouldn't work in its current form though, since as
> mentioned in my previous email it seems that only the target CONFIG_*
> defines and not the device CONFIG_* defines are present when processing
> hmp-commands-info.hx.

Yeah, that's where the pain comes in.  While QAPI schema can be made
conditional on a few CONFIG_* parameters - basically those derived
from global configure time options, it is impossible for this to be
with with target specific options like the device CONFIG_* defines.

This is why I suggested in my othuer reply that it would need to be
done with a generic 'info dev-debug' / 'x-query-dev-debug' command
that can be registered unconditionally, and then individual devices
plug into it.



Regards,
Daniel
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