Re: [Qemu-devel] [PATCH] vl.c: fixed regression of machine error message

[Marcel Apfelbaum]

On 02/08/2016 10:58 AM, Laszlo Ersek wrote:
> On 02/07/16 17:24, Marcel Apfelbaum wrote:
> > Commit e1ce0c3cb(vl.c: fix regression when reading machine type from config 
> > file)
> > fixed the error message when the machine type was supplied inside the
> > config file. However now the option name is not displayed correctly if
> > the error happens when the machine is specified at command line.
> >
> > Running
> >      ./x86_64-softmmu/qemu-system-x86_64 -M q35-1.5 -redir tcp:8022::22
> > will result in the error message:
> >      qemu-system-x86_64: -redir tcp:8022::22: unsupported machine type
> >      Use -machine help to list supported machines
> >
> > Fixed it by saving the error location and also extracted the code
> > dealing with machine options into a separate function.
> >
> > Reported-by: Michael S. Tsirkin <address@hidden>
> > Signed-off-by: Marcel Apfelbaum <address@hidden>
> > ---
> >
> > Hi,
> >
> > I hope I used "location" correctly, if anyone is aware of a simpler
> > approach please advice.
> >
> > Thanks,
> > Marcel
> >
> >   vl.c | 34 +++++++++++++++++++++++-----------
> >   1 file changed, 23 insertions(+), 11 deletions(-)
> >
> > diff --git a/vl.c b/vl.c
> > index f043009..f8a9213 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -2751,6 +2751,26 @@ static const QEMUOption *lookup_opt(int argc, char 
> > **argv,
> >       return popt;
> >   }
> >
> > +static void machine_set_options(Location *machine_opt_loc,
> > +                                MachineClass **machine_class)
> > +{
> > +    const char *optarg;
> > +    Location *curr = loc_push_restore(machine_opt_loc);
> > +
> > +    optarg = qemu_opt_get(qemu_get_machine_opts(), "type");
> > +    if (optarg) {
> > +        *machine_class = machine_parse(optarg);
> > +    }
> > +
> > +    if (*machine_class == NULL) {
> > +        error_report("No machine specified, and there is no default");
> > +        error_printf("Use -machine help to list supported machines\n");
> > +        exit(1);
> > +    }
> > +
> > +    loc_pop(curr);
> > +}
> > +
> >   static int machine_set_property(void *opaque,
> >                                   const char *name, const char *value,
> >                                   Error **errp)
> > @@ -2975,6 +2995,7 @@ int main(int argc, char **argv, char **envp)
> >       const char *optarg;
> >       const char *loadvm = NULL;
> >       MachineClass *machine_class;
> > +    Location machine_opt_loc = {0};
> >       const char *cpu_model;
> >       const char *vga_model = NULL;
> >       const char *qtest_chrdev = NULL;
> > @@ -3671,6 +3692,7 @@ int main(int argc, char **argv, char **envp)
> >                   break;
> >               case QEMU_OPTION_M:
> >               case QEMU_OPTION_machine:
> > +                loc_save(&machine_opt_loc);
> >                   olist = qemu_find_opts("machine");
> >                   opts = qemu_opts_parse_noisily(olist, optarg, true);
> >                   if (!opts) {
> > @@ -4019,17 +4041,7 @@ int main(int argc, char **argv, char **envp)
> >
> >       replay_configure(icount_opts);
> >
> > -    opts = qemu_get_machine_opts();
> > -    optarg = qemu_opt_get(opts, "type");
> > -    if (optarg) {
> > -        machine_class = machine_parse(optarg);
> > -    }
> > -
> > -    if (machine_class == NULL) {
> > -        error_report("No machine specified, and there is no default");
> > -        error_printf("Use -machine help to list supported machines\n");
> > -        exit(1);
> > -    }
> > +    machine_set_options(&machine_opt_loc, &machine_class);
> >
> >       set_memory_options(&ram_slots, &maxram_size, machine_class);
>
> Sorry, I sent my email before noticing yours (in the original thread,
> "Re: [Qemu-devel] command line error handling broken?").
>
> Looks good (extracting machine_set_options()), but I think you don't
> need to save the location for the option separately; the location gets
> saved in the option automatically. It can be restored with
> qemu_opts_loc_restore(), however it doesn't combine push & restore, so a
> none location should be pushed first.
>
> Also, "set_machine_options" would match "set_memory_options" better,
> just below.

Hi Laszlo,

Thanks for the review. I'll post an updated patch shortly.

Thanks,
Marcel

> Thanks
> Laszlo