On Thu, 28 Jul 2011 19:52:31 +0200 Jan Kiszka <jan.kis...@web.de> wrote:
> On 2011-07-28 19:48, Luiz Capitulino wrote: > > On Thu, 28 Jul 2011 14:39:23 -0300 > > Luiz Capitulino <lcapitul...@redhat.com> wrote: > > > >> On Thu, 28 Jul 2011 17:20:41 +0200 > >> Jan Kiszka <jan.kis...@web.de> wrote: > >> > >>> On 2011-07-28 17:18, Luiz Capitulino wrote: > >>>> On Thu, 28 Jul 2011 16:19:19 +0200 > >>>> Jan Kiszka <jan.kis...@web.de> wrote: > >>>> > >>>>> On 2011-07-28 15:37, Avi Kivity wrote: > >>>>>> On 07/28/2011 04:31 PM, Luiz Capitulino wrote: > >>>>>>> On Thu, 28 Jul 2011 10:23:22 +0300 > >>>>>>> Avi Kivity<a...@redhat.com> wrote: > >>>>>>> > >>>>>>>> On 07/28/2011 12:44 AM, Blue Swirl wrote: > >>>>>>>> > On Wed, Jul 27, 2011 at 9:42 PM, Luiz > >>>>>>> Capitulino<lcapitul...@redhat.com> wrote: > >>>>>>>> > > This function should be used when the VM is not supposed to > >>>>>>> resume > >>>>>>>> > > execution (eg. by issuing 'cont' monitor command). > >>>>>>>> > > > >>>>>>>> > > Today, we allow the user to resume execution even when: > >>>>>>>> > > > >>>>>>>> > > o the guest shuts down and -no-shutdown is used > >>>>>>>> > > o there's a kvm internal error > >>>>>>>> > > o loading the VM state with -loadvm or "loadvm" in the > >>>>>>> monitor fails > >>>>>>>> > > > >>>>>>>> > > I think only badness can happen from the cases above. > >>>>>>>> > > >>>>>>>> > I'd suppose a system_reset should bring the system back to > >>>>>>> sanity and > >>>>>>>> > then clear vm_permanent_stopped (where's -ly?) > >>>>>>> > >>>>>>> What's -ly? > >>>>>>> > >>>>>> > >>>>>> permanent-ly. > >>>>>> > >>>>>>>> > except maybe for KVM > >>>>>>>> > internal error if that can't be recovered. Then it would not very > >>>>>>>> > permanent anymore, so the name would need adjusting. > >>>>>>>> > >>>>>>>> Currently, all kvm internal errors are recoverable by reset (and > >>>>>>>> possibly by fiddling with memory/registers). > >>>>>>> > >>>>>>> Ok, but a poweroff in the guest isn't recoverable with system_reset > >>>>>>> right? Or does it depend on the guest? > >>>>>> > >>>>>> Right, it's not recoverable if you shut the power down where the > >>>>>> tractor > >>>>>> beam is coupled to the main reactor. > >>>>> > >>>>> system_reset will bring all emulated devices back into their power-on > >>>>> state - unless we have remaining bugs to fix. Actually, one may consider > >>>>> issuing this reset automatically on vm_start after "permant" vm_stop. > >> > >> The only permanent vm_stop we'd have is poweroff when -no-shutdown is used. > >> > >> Are you saying that system_reset should be able to recover from that too? > > > > It already does, so we don't have permanent stops. > > Exactly. We just have stops over inconsistent states that require a > reset to continue with anything useful. Yes. If I got you right, you suggest that we do the reset automatically. I think it's better to let the user do it, because s/he might want to do something else before resetting. For example, for the kvm error the user might want to save the vm state. For the poweroff case with -no-shutdown it's probably fine, but I don't want to hard code special cases. It's better and easier to treat them all as "require system_reset to recover".
