On 2011-07-28 20:00, Luiz Capitulino wrote: > 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.
Associating the reset with a cont means requesting an explicit action from the user. I'm not suggesting to do the reset when the stop state is entered. > > 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". In any case, we need to tag the current state as stopped-and-invalid or so vs. a normal stop. That remains a valuable first step. How to deal with that information is the second one. Jan
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