Re: [Qemu-devel] Re: [PATCH 11/11] QMP: Command-line flag to enable control mode

[Anthony Liguori]

Avi Kivity wrote:
> On 06/23/2009 01:11 PM, Jan Kiszka wrote:
> > > If we support multiple monitors, it might be desirable to allow the
> > > app owning the main 'control' monitor channel to be able to indicate
> > > that additional monitor channels are read-only. eg, so libvirt could
> > > allow the user to connect to the monitor to run 'info' commands for
> > > debug support without risk of having state changed behind its back
> > >      
> >
> > Couldn't libvirt deal with update given we provide them as events?
> > Otherwise, your suggestion makes sense, definitely as long as it would
> > wreck libvirt's internal house keeping or for commands that are not
> > synchronizable.
> >    
>
> It would be a nightmare, consider both libvirt and a user hotplugging 
> something into the same pci slot, or a user starting migration, or 
> quitting, or ...
>
> Having -monitor readonly makes sense.

I don't like such a concept.  If a user goes to the trouble to create a 
second monitor, then they need to know what they're doing.

libvirt can simply not expose the option to the user.  Clever users can 
change the emulator tag to point to a script that they can use to create 
a second monitor.

Regards,

Anthony Liguori