Re: [Qemu-devel] [PATCH v4 3/9] cli: add -preconfig option

[Igor Mammedov <imammedo@redhat.com>]

On Tue, 27 Mar 2018 17:05:41 +0200
Igor Mammedov <imammedo@redhat.com> wrote:

> On Fri, 23 Mar 2018 18:25:08 -0300
> Eduardo Habkost <ehabkost@redhat.com> wrote:
> 
> > On Mon, Mar 12, 2018 at 02:11:09PM +0100, Igor Mammedov wrote:  
> [...]
[...]
> > > @@ -1886,6 +1895,13 @@ static bool main_loop_should_exit(void)
> > >      RunState r;
> > >      ShutdownCause request;
> > >  
> > > +    if (preconfig_exit_requested) {
> > > +        if (runstate_check(RUN_STATE_PRECONFIG)) {    
> > 
> > Is it possible to have preconfig_exit_request set outside of
> > RUN_STATE_PRECONFIG?  When and why?  
> preconfig_exit_requested is initialized with TRUE and
> in combo with '-inmigrate' we need this runstate check.
> it's the same as it was with
>  { RUN_STATE_PRELAUNCH, RUN_STATE_INMIGRATE },
> which I probably should remove (I need to check it though)
[...]

> > > @@ -4594,6 +4623,10 @@ int main(int argc, char **argv, char **envp)
> > >      }
> > >      parse_numa_opts(current_machine);
> > >  
> > > +    /* do monitor/qmp handling at preconfig state if requested */
> > > +    main_loop();    
> > 
> > Wouldn't it be simpler to do "if (!preconfig) { main_loop(); }"
> > instead of entering main_loop() just to exit immediately?  
> The thought didn't cross my mind, it might work and more readable
> as one doesn't have to jump into main_loop() to find out that
> it would exit immediately.
> I'll try to it on respin.
Well doing as suggested end ups more messy:

    @@static bool main_loop_should_exit(void)
    ...
    if (preconfig_exit_requested) {
        runstate_set(RUN_STATE_PRELAUNCH);                                        
        return true;
    }
   
    @@main
    /* do monitor/qmp handling at preconfig state if requested */
    if (!preconfig_exit_requested) {
        main_loop();
    } else if (runstate_check(RUN_STATE_PRECONFIG)) {
        runstate_set(RUN_STATE_PRELAUNCH);
    }
    preconfig_exit_requested = false;
    ...

I'd prefer original v4 approach, where only main_loop_should_exit()
has to deal with state transitions and book-keeping.

[...]