Re: [Qemu-devel] [PATCH V4] vl.c: fixed regression in machine error message

[Marcel Apfelbaum]

On 02/11/2016 08:31 PM, Eduardo Habkost wrote:
> On Mon, Feb 08, 2016 at 01:54:29PM +0200, 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 restoring the error location and also extracted the code
> > dealing with machine options into a separate function.
> >
> > Reported-by: Michael S. Tsirkin <address@hidden>
> > Reviewed-by: Laszlo Ersek <address@hidden>
> > Signed-off-by: Marcel Apfelbaum <address@hidden>
> > ---
> >
> > v3 -> v4:
> >     - removed double call of loc_push_none (thanks again Laszlo)
> >
> > v2 -> v3:
> >   - fixed commit message and called qemu_get_machine_opts only once. (thanks 
> > Laszlo)
> >
> > v1 -> v2:
> >   - Addressed Laszlo Ersek's comments:
> >     - no need to save the machine options location, is saved in opts
> >     - rename the extracted method to set_machine_options
> >     - added the bug reporter to the CC
> >
> >   - tested with and without the config file and the error message is now OK:
> >   config file:
> >      - qemu-system-x86_64:machine-bug.conf:3: unsupported machine type
> >   cli:
> >     - qemu-system-x86_64: -M q35-1.5: unsupported machine type
> >
> > Thanks,
> > Marcel
> >
> >   vl.c | 38 +++++++++++++++++++++++++++-----------
> >   1 file changed, 27 insertions(+), 11 deletions(-)
> >
> > diff --git a/vl.c b/vl.c
> > index 2c03f54..5e22a35 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -2748,6 +2748,31 @@ static const QEMUOption *lookup_opt(int argc, char 
> > **argv,
> >       return popt;
> >   }
> >
> > +static void set_machine_options(MachineClass **machine_class)
> > +{
> > +    const char *optarg;
> > +    QemuOpts *opts;
> > +    Location loc;
> > +
> > +    loc_push_none(&loc);
> > +
> > +    opts = qemu_get_machine_opts();
> > +    qemu_opts_loc_restore(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);
> > +    }
> > +
> > +    loc_pop(&loc);
> > +}
> > +
> >   static int machine_set_property(void *opaque,
> >                                   const char *name, const char *value,
> >                                   Error **errp)
> > @@ -4028,17 +4053,7 @@ 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);
> > -    }
> > +    set_machine_options(&machine_class);
> >
> >       set_memory_options(&ram_slots, &maxram_size, machine_class);
> [Extra context for reference:]
> >     loc_set_none();
>
> You are fixing the machine error message, but not the root cause:

Hi,

I knew that it would not solve all the cases but
the machine error message is a regression while other
were there way before (as far as I know)

I was specifically looking to fix the machine error regression.

>    $ ./x86_64-softmmu/qemu-system-x86_64 -m size= -vnc :0
>    qemu-system-x86_64: -vnc :0: missing 'size' option value
>    $ ./x86_64-softmmu/qemu-system-x86_64 -icount rr=x -vnc :0
>    qemu-system-x86_64: -vnc :0: Invalid icount rr option: x
>
> Moving the loc_set_none() call above replay_configure() should fix the bug in
> the three cases.

I am really no expert in loc stuff, but it seamed to me it is placed
especially after all the options are parsed. Maybe we need another
call to loc_set_none before replay_configure instead of moving it?

If you think it should be moved, please go ahead :)
is an one liner and the idea was yours.

> Setting location in set_machine_options()

This is done in this patch.

, set_memory_options(), and
> replay_configure() would be nice, too.

I can do it on those functions too, if you agree to the way
is done in set_machine_options

 But I would prefer to apply a one-line
> fix first, and then consider improving the machine/memory/icount error
> messages.

Sure. (set_machine_options is introduced in this patch)

Thanks,
Marcel

>