Re: [Qemu-devel] [PATCH v14 1/4] add a new runstate: RUN_STATE_GUEST_PANICKED

[Paolo Bonzini <pbonzini@redhat.com>]

Il 20/03/2013 09:58, Markus Armbruster ha scritto:
> Let's examine the other transitions to RUN_STATE_PAUSED, and whether
> they can now come from RUN_STATE_GUEST_PANICKED:
> 
> * process_incoming_migration_co()
> 
>   No, because we're in RUN_STATE_INMIGRATE here, aren't we?  Juan?

Yes.

> * qmp_stop()
> 
>   No, because vm_stop() calls do_vm_stop() to do the actual state
>   transition, which protects it by runstate_is_running().
> 
>   We can ignore the conditional, it merely punts the vm_stop() to the
>   main loop.
> 
> Next question: RUN_STATE_INTERNAL_ERROR and RUN_STATE_SHUTDOWN may go to
> RUN_STATE_FINISH_MIGRATE, but RUN_STATE_GUEST_PANICKED may not.  Why?

RUN_STATE_FINISH_MIGRATE is reached with vm_stop_force_state, so every
state can go there.  Next question: why doesn't the switch to
RUN_STATE_SAVE_VM use vm_stop_force_state?

Next question: almost all states go to RUN_STATE_FINISH_MIGRATE, the
same would hold for RUN_STATE_SAVE_VM if it started using
vm_stop_force_state.  There are few exceptions, and I'm not even sure
all of them are correct (why can't RUN_STATE_DEBUG go to
RUN_STATE_FINISH_MIGRATE?).

Should vm_stop_force_state override the runstate check (either directly,
or by interposing a transition to RUN_STATE_PAUSED? The few outliers can
be handled with manually-placed assertions.

Paolo