[libvirt] [Qemu-devel] pvpanic plans?

[Christian Borntraeger]

On 31/10/13 15:30, Michael S. Tsirkin wrote:
> On Thu, Oct 24, 2013 at 10:39:03AM +0800, Hu Tao wrote:
>> Hi All,
>>
>> I know it's been a long time since this thread. But qemu 1.7 is
>> releasing, do you have any consensus on this?
>>
>> Thanks.
> 
> 
> I think the biggest issue is the new PANICKED state.

I thought the problem was that the new device broke windows and all
the following hazzle.

> Guests already have simple ways to halt the CPU,
> and actually do.  I think a new state was a mistake.
> So how about the following? Does it break anything?
> (Untested).

Please note that on s390 we also do the panic state (on a disabled wait)


"target-s390x/kvm.c"
...

                    monitor_protocol_event(QEVENT_GUEST_PANICKED, data);
                    qobject_decref(data);
                    vm_stop(RUN_STATE_GUEST_PANICKED);
...

Currently it is possible to restart libvirt, e.g. after an update and then it will
be able to fetch the full state of a guest via QMP. It will then also be able to
detect that this guest panicked some time ago.
I think one issue when removing the PANICKED state is that libvirt can then no 
longer detect that state, correct?

Christian


> 
> Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
> 
> diff --git a/hw/misc/pvpanic.c b/hw/misc/pvpanic.c
> index 226e298..2055afc 100644
> --- a/hw/misc/pvpanic.c
> +++ b/hw/misc/pvpanic.c
> @@ -51,7 +51,6 @@ static void handle_event(int event)
> 
>      if (event & PVPANIC_PANICKED) {
>          panicked_mon_event("pause");
> -        vm_stop(RUN_STATE_GUEST_PANICKED);
>          return;
>      }
>  }
> 
>