Re: [Qemu-devel] [PATCH] migration: notify runstate immediately before vcpu stops

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Yan Zhao (yan.y.zhao@intel.com) wrote:
> for some devices to do live migration, it is needed to do something
> immediately before vcpu stops. add a notification here.
> 
> Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
> ---
>  cpus.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/cpus.c b/cpus.c
> index b09b702..d5d4abe 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -1068,6 +1068,7 @@ static int do_vm_stop(RunState state, bool send_stop)
>      int ret = 0;
>  
>      if (runstate_is_running()) {
> +        vm_state_notify(1, state);

SO that's quite interesting in that you'll end up getting a
notificatiion like 'running=true, state=RUN_STATE_SHUTDOWN'
that might be unexpected by existing callers.

Have you checked existing callers?  Also does this cause another event
to be sent on the QMP - if so we need to chekc if this would confuse
libvirt.

Dave

>          cpu_disable_ticks();
>          pause_all_vcpus();
>          runstate_set(state);
> -- 
> 2.7.4
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK