On Fri, 02 Sep 2011 16:32:25 +0200
Jan Kiszka <jan.kis...@siemens.com> wrote:
> On 2011-09-02 16:28, Luiz Capitulino wrote:
> > On Thu, 01 Sep 2011 22:58:51 +0200
> > Jan Kiszka <jan.kis...@web.de> wrote:
> >
> >> On 2011-09-01 20:39, Luiz Capitulino wrote:
> >>> On Thu, 01 Sep 2011 20:30:57 +0200
> >>> Jan Kiszka <jan.kis...@siemens.com> wrote:
> >>>
> >>>> On 2011-09-01 20:12, Luiz Capitulino wrote:
> >>>>> Currently, only vm_start() and vm_stop() change the VM state.
> >>>>> That's, the state is only changed when starting or stopping the VM.
> >>>>>
> >>>>> This commit adds the runstate_set() function, which makes it possible
> >>>>> to also do state transitions when the VM is stopped or running.
> >>>>>
> >>>>> Additional states are also added and the current state is stored.
> >>>>>
> >>>>> Signed-off-by: Luiz Capitulino <lcapitul...@redhat.com>
> >>>>> ---
> >>>>> cpus.c | 1 +
> >>>>> migration.c | 8 +++++++-
> >>>>> sysemu.h | 10 +++++++++-
> >>>>> vl.c | 20 ++++++++++++++++++++
> >>>>> 4 files changed, 37 insertions(+), 2 deletions(-)
> >>>>>
> >>>>
> >>>> ...
> >>>>
> >>>>> diff --git a/vl.c b/vl.c
> >>>>> index f0b56a4..59f71fc 100644
> >>>>> --- a/vl.c
> >>>>> +++ b/vl.c
> >>>>> @@ -321,6 +321,22 @@ static int default_driver_check(QemuOpts *opts,
> >>>>> void *opaque)
> >>>>> }
> >>>>>
> >>>>> /***********************************************************/
> >>>>> +/* QEMU state */
> >>>>> +
> >>>>> +static RunState current_run_state = RSTATE_NO_STATE;
> >>>>> +
> >>>>> +bool runstate_check(RunState state)
> >>>>> +{
> >>>>> + return current_run_state == state;
> >>>>> +}
> >>>>> +
> >>>>> +void runstate_set(RunState state)
> >>>>> +{
> >>>>> + assert(state < RSTATE_MAX);
> >>>>> + current_run_state = state;
> >>>>
> >>>> I still think this should check for valid state transitions instead of
> >>>> blindly accepting what the caller passes in.
> >>>
> >>> I thought your comment where more like a future enhancement than
> >>> a request for change.
> >>
> >> I think we want this now to document at a central place which
> >> transitions are valid and which not. State machines without such checks
> >> break sooner or later, subtly.
> >
> > Ok, I'll do it.
> >
> > Do you have any suggestion on the preferred way to document it?
> > Should I use english or try some ascii art?
>
> My idea is programmatic:
>
> void runstate_set(RunState new_state)
> {
> switch (current_state) {
> case X:
> /* potential comment on why only X->Y or ... is valid */
> if (new_state == Y || ...) {
> break;
> } else {
> abort();
> }
Ah, ok. I was thinking in having some fancy graph as documentation,
but let's do the simpler way then.
