Re: [Qemu-devel] pvpanic plans?

[Paolo Bonzini]

Il 31/10/2013 15:52, Michael S. Tsirkin ha scritto:
>> > Yes, it does.
> What does it break exactly?

The point of a panicked event is to examine the guest at a particular
moment in time (e.g. host-initiated crash dump).  If you let the guest
run, it may reboot and prevent you from getting a meaningful dump.

>> > But I think that, once we make the pvpanic device is
>> > optional, to a large extent there is no bug.  Adding the pvpanic
>> > device to the VM will make libvirt obey <oncrash> instead of the
>> > in-guest setting, and that's it.
>> > 
>> > Two months have passed and no casualties have been reported due to
>> > pvpanic.  Let's just remove the auto-pvpanic from all machine types in
>> > 1.7 (yes, that's backwards incompatible in a strict sense), document
>> > it in the release notes, and hope that the old QEMU versions with
>> > mandatory pvpanic die of old age.
> 
> Nod. I'm fine with that.
> 
> I think we still need to do get rid of the PANICKED state somehow.
> If we can't replace it with RUNNING state, let's replace it with PAUSED.
> 
> For example, you can't continue from panicked for some reason.
> You can't do a reset.  But you can pause and then continue.

We need to keep the PANICKED state, but we can make it a normal
"resumable" state.

Basically it's patches 1 and 2 at
http://permalink.gmane.org/gmane.comp.emulators.qemu/229131.  Rebasing
will fix the problem highlighted in the commit message of patch 2.

Paolo