Re: [libvirt] pvpanic plans?

On Thu, Oct 31, 2013 at 03:56:42PM +0100, Paolo Bonzini wrote: > 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. Well we trust guest anyway, so I think we can trust it to call halt.

>>>> 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. If it's resumable how is it different from PAUSED?

Looks like all transitions from paused state should be allowed from panicked state. So why keep it separate?