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. > > What to do if the transition is invalid? abort()? Yes. Jan
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