Re: [Qemu-devel] [PATCH v2 1/2] vl: don't use RUN_STATE_PRECONFIG as initial state

["Daniel P. Berrangé" <berrange@redhat.com>]

On Mon, Jun 04, 2018 at 01:03:44PM +0100, Daniel P. Berrangé wrote:

> diff --git a/vl.c b/vl.c
> index 06031715ac..30d0e985f0 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -561,7 +561,7 @@ static int default_driver_check(void *opaque, QemuOpts *opts, Error **errp)
>  /***********************************************************/
>  /* QEMU state */
>  
> -static RunState current_run_state = RUN_STATE_PRECONFIG;
> +static RunState current_run_state = RUN_STATE_NONE;

BTW, an alternative to introducing a RNU_STATE_NONE is to just use
an intentionally invalid enum value here eg

   static RunState current_run_state = -1;

on the basis that while we're parsing argv[], current_run_state
is not really meaningful. Only once we're done with argv[] do
we know what valid state will be used as the initial value of
current_run_state.

This would avoid exposing the "none" concept in QAPI schema,
or the runstate transitions list.

>  
>  /* We use RUN_STATE__MAX but any invalid value will do */
>  static RunState vmstop_requested = RUN_STATE__MAX;
> @@ -574,12 +574,11 @@ typedef struct {
>  
>  static const RunStateTransition runstate_transitions_def[] = {
>      /*     from      ->     to      */
> +    { RUN_STATE_NONE, RUN_STATE_PRELAUNCH },
> +    { RUN_STATE_NONE, RUN_STATE_PRECONFIG },
> +    { RUN_STATE_NONE, RUN_STATE_INMIGRATE },
> +
>      { RUN_STATE_PRECONFIG, RUN_STATE_PRELAUNCH },
> -      /* Early switch to inmigrate state to allow  -incoming CLI option work
> -       * as it used to. TODO: delay actual switching to inmigrate state to
> -       * the point after machine is built and remove this hack.
> -       */
> -    { RUN_STATE_PRECONFIG, RUN_STATE_INMIGRATE },
>  
>      { RUN_STATE_DEBUG, RUN_STATE_RUNNING },
>      { RUN_STATE_DEBUG, RUN_STATE_FINISH_MIGRATE },
> @@ -618,7 +617,6 @@ static const RunStateTransition runstate_transitions_def[] = {
>  
>      { RUN_STATE_PRELAUNCH, RUN_STATE_RUNNING },
>      { RUN_STATE_PRELAUNCH, RUN_STATE_FINISH_MIGRATE },
> -    { RUN_STATE_PRELAUNCH, RUN_STATE_INMIGRATE },
>  
>      { RUN_STATE_FINISH_MIGRATE, RUN_STATE_RUNNING },
>      { RUN_STATE_FINISH_MIGRATE, RUN_STATE_PAUSED },
> @@ -1522,7 +1520,7 @@ static pid_t shutdown_pid;
>  static int powerdown_requested;
>  static int debug_requested;
>  static int suspend_requested;
> -static bool preconfig_exit_requested = true;
> +static bool preconfig_exit_requested;
>  static WakeupReason wakeup_reason;
>  static NotifierList powerdown_notifiers =
>      NOTIFIER_LIST_INITIALIZER(powerdown_notifiers);
> @@ -3572,7 +3570,12 @@ int main(int argc, char **argv, char **envp)
>                  }
>                  break;
>              case QEMU_OPTION_preconfig:
> -                preconfig_exit_requested = false;
> +                if (!runstate_check(RUN_STATE_NONE)) {
> +                    error_report("'--preconfig' and '--incoming' options are "
> +                                 "mutually exclusive");
> +                    exit(EXIT_FAILURE);
> +                }
> +                runstate_set(RUN_STATE_PRECONFIG);
>                  break;
>              case QEMU_OPTION_enable_kvm:
>                  olist = qemu_find_opts("machine");
> @@ -3768,9 +3771,12 @@ int main(int argc, char **argv, char **envp)
>                  }
>                  break;
>              case QEMU_OPTION_incoming:
> -                if (!incoming) {
> -                    runstate_set(RUN_STATE_INMIGRATE);
> +                if (!runstate_check(RUN_STATE_NONE)) {
> +                    error_report("'--preconfig' and '--incoming' options are "
> +                                 "mutually exclusive");
> +                    exit(EXIT_FAILURE);
>                  }
> +                runstate_set(RUN_STATE_INMIGRATE);
>                  incoming = optarg;
>                  break;
>              case QEMU_OPTION_only_migratable:
> @@ -3943,14 +3949,12 @@ int main(int argc, char **argv, char **envp)
>       */
>      loc_set_none();
>  
> -    replay_configure(icount_opts);
> -
> -    if (incoming && !preconfig_exit_requested) {
> -        error_report("'preconfig' and 'incoming' options are "
> -                     "mutually exclusive");
> -        exit(EXIT_FAILURE);
> +    if (runstate_check(RUN_STATE_NONE)) {
> +        runstate_set(RUN_STATE_PRELAUNCH);
>      }
>  
> +    replay_configure(icount_opts);
> +
>      machine_class = select_machine();
>  
>      set_memory_options(&ram_slots, &maxram_size, machine_class);
> @@ -4471,7 +4475,9 @@ int main(int argc, char **argv, char **envp)
>      parse_numa_opts(current_machine);
>  
>      /* do monitor/qmp handling at preconfig state if requested */
> -    main_loop();
> +    if (runstate_check(RUN_STATE_PRECONFIG)) {
> +        main_loop();
> +    }
>  
>      /* from here on runstate is RUN_STATE_PRELAUNCH */
>      machine_run_board_init(current_machine);
> -- 
> 2.17.0
> 

Regards,
Daniel
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