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

[Igor Mammedov]

On Tue, 17 Oct 2017 10:47:40 +0200
Paolo Bonzini <address@hidden> wrote:

> On 16/10/2017 19:17, Eduardo Habkost wrote:
> >> 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).  
> 
> It is but, alternatively, you could delay creating the "none" machine
> until the last second.  The important part, in my opinion, is having a
> good command-line interface that we can freeze even if the
> implementation below leaves something to be desired.
I sort of don't get how '-M none' could be used to build usable
machine (at least currently).

Do we really need "-M none" for dynamic configuration?
I'd imagine doing following instead:
  qemu -monitor stdio -dynconfig
  (qemu) query-machines
  ...
  (qemu) set-option machine pc,accel=kvm
    # machine object is created
  (qemu) set-option smp 1,maxcpus
  (qemu) info hotpluggable-cpus
  ...
  (qemu) set-option numa node
  (qemu) set-option numa cpu,node-id=0,socket=0
  (qemu) set-option numa cpu,node-id=0,socket=1
  (qemu) c

I'd start to make it working from 'info hotpluggable-cpus'
as it's close to my current project of making cpu-hotplug/numa
working nice together and we can expand the same interface to work
at earlier stages on top of that.