[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH] runstate: ignore exit request in finish migrate state
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [PATCH] runstate: ignore exit request in finish migrate state |
Date: |
Tue, 22 Oct 2019 11:10:15 +0100 |
User-agent: |
Mutt/1.12.1 (2019-06-15) |
* Paolo Bonzini (address@hidden) wrote:
> On 17/10/19 12:18, Laurent Vivier wrote:
> > Trying to reboot a VM while a migration is running can
> > move to the prelaunch state (because of the reset) while
> > the runstate is in finish migrate state.
> > As the logical step after the finish migrate is postmigrate,
> > this can create an invalid state transition from prelaunch state
> > to postmigrate state and this raises an error and aborts:
> >
> > invalid runstate transition: 'prelaunch' -> 'postmigrate'
> >
> > As we are not able to manage reset in finish migrate state the
> > best we can do is to ignore any changes and delay them until
> > the next state which should be postmigrate and which should allow
> > this kind of transition.
> >
> > Reported-by: Lukáš Doktor <address@hidden>
> > Suggested-by: Dr. David Alan Gilbert <address@hidden>
> > Signed-off-by: Laurent Vivier <address@hidden>
> > ---
> > vl.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/vl.c b/vl.c
> > index 0a295e5d77d6..dc71c822ba24 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -1744,6 +1744,9 @@ static bool main_loop_should_exit(void)
> > RunState r;
> > ShutdownCause request;
> >
> > + if (runstate_check(RUN_STATE_FINISH_MIGRATE)) {
> > + return false;
> > + }
> > if (preconfig_exit_requested) {
> > if (runstate_check(RUN_STATE_PRECONFIG)) {
> > runstate_set(RUN_STATE_PRELAUNCH);
> >
>
> Your patch makes sense, but I don't understand this function very much.
> In particular I don't understand why it returns true when
> preconfig_exit_requested is true. Wouldn't that cause main_loop() and
> thus QEMU to exit? Igor, can you help?
It's because we now run main_loop() twice; once in the preconfig state
and once the main main loop.
4323 /* do monitor/qmp handling at preconfig state if requested */
4324 main_loop();
....
4452 os_setup_post();
4453
4454 main_loop();
4455
4456 gdbserver_cleanup();
> Paolo
Dave
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK