Re: [Qemu-devel] [RFC 4/6] CLI: add -paused option

[Eduardo Habkost]

On Mon, Oct 16, 2017 at 07:01:01PM +0200, Paolo Bonzini wrote:
> On 16/10/2017 18:59, Eduardo Habkost wrote:
> >> +DEF("paused", HAS_ARG, QEMU_OPTION_paused, \
> >> +    "-paused [state=]postconf|preconf\n"
> >> +    "                postconf: pause QEMU after machine is initialized\n"
> >> +    "                preconf: pause QEMU before machine is initialized\n",
> >> +    QEMU_ARCH_ALL)
> > I would like to allow pausing before machine-type is selected, so
> > management could run query-machines before choosing a
> > machine-type.  Would that need a third "-pause" mode, or will we
> > be able to change "preconf" to pause before select_machine() is
> > called?
> > 
> > The same probably applies to other things initialized before
> > machine_run_board_init() that could be configurable using QMP,
> > including but not limited to:
> > * Accelerator configuration
> > * Registering global properties
> > * RAM size
> > * SMP/CPU configuration
> 
> Should (or could) "-M none" be changed in a backwards-compatible way to
> allow such preconfiguration?  For example
> 
>   qemu -M none -monitor stdio
>   (qemu) machine-set-options pc,accel=kvm
>   (qemu) c

Sounds like an interesting idea.  It would require ensuring it's
really safe to destroy current_machine/accel (and other global
state) and replace them with another object on the fly (which is
probably a nice goal by itself).

-- 
Eduardo