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

[Jan Kiszka]

Daniel P. Berrange wrote:
> On Tue, Jun 23, 2009 at 11:03:09AM +0200, Jan Kiszka wrote:
>> Luiz Capitulino wrote:
>>> This change adds a flag called 'control' to the already existing
>>> '-monitor' command-line option. This flag can be used to enable
>>> control mode.
>>>
>>> Its syntax is:
>>>
>>> qemu [...] -monitor control,<device>
>>>
>>> Where <device> is a chardev (excluding 'vc', for obvious reasons).
>>>
>>> For example:
>>>
>>> $ qemu [...] -monitor control,tcp:localhost:4444,server
>>>
>>> Will run QEMU in control mode, waiting for a client TCP connection
>>> on localhost port 4444.
>>>
>>> Signed-off-by: Luiz Capitulino <address@hidden>
>> At this chance, I would vote for "[PATCH 12/11] Allow multiple -monitor
>> instances". I think Anthony posted such a patch before. Now we should
>> really include this as your extension may block the stand-alone -monitor
>> switch for the control channel, preventing to additionally set up one
>> (or more) for debugging purposes.
> 
> 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.

Jan

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