Re: [Qemu-devel] [RFC 1/1] Execute arbitrary QMP commands from command line

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

On Thu, Jan 29, 2015 at 03:06:37PM +0000, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> 
> For an incoming migration it's potentially useful to be able to set
> capabilities and parameters prior to opening the connection, while
> a separate option for that would have been possible it seems better
> to give access to all the existing migration capabilities, parameters
> etc.  The least restrictive way of doing this is to allow arbitrary
> QMP commands to be executed prior to the -incoming being processed.
> 
> As an example:
> 
> ./bin/qemu-system-x86_64 -nographic -nodefaults -qmp-command '{"execute": "migrate-set-capabilities", "arguments":{"capabilities":[{"capability":"xbzrle","state":true}]}}' -qmp-command '{"execute": "query-migrate-capabilities"}' -incoming tcp::444

I'm unclear how we'd easily deal with the response from commands
invoked this way, to get replies and/or errors. Also, it might
be the case that we need to conditionally run certain commands
depending on the result of earlier commands.

Wouldn't it make more sense to simply add a 'migrate_incoming' QMP
command, and stop using -incoming altogether, so we just have normal
QMP access ?

eg,

    #  qemu-system-x86_64 ....device args...  -S
    (qmp) ....arbitrary QMP commands ..
    (qmp) {"execute":"migrate-incoming", "arguments": { "uri": "tcp::44" }}

Regards,
Daniel
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