Re: [Qemu-devel] [PATCH V2] vl.c: fixed regression in machine error message

[Laszlo Ersek <lersek@redhat.com>]

On 02/08/16 11:09, 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.
> 
> 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 no OK:

--> "is *now* OK". The typo ("no OK") should be please fixed up by the
maintainer (unless another round is necessary).

>  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
> 
> Reported-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
> ---
>  vl.c | 38 +++++++++++++++++++++++++++-----------
>  1 file changed, 27 insertions(+), 11 deletions(-)
> 
> diff --git a/vl.c b/vl.c
> index f043009..dd29807 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -2751,6 +2751,32 @@ 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();
> +    loc_push_none(&loc);
> +    qemu_opts_loc_restore(opts);
> +
> +    optarg = qemu_opt_get(qemu_get_machine_opts(), "type");

Not particularly important, but you could just pass "opts" as first arg
here, rather than calling qemu_get_machine_opts() again. For style
reasons, can you clean it up?

With that:

Reviewed-by: Laszlo Ersek <lersek@redhat.com>

Thanks
Laszlo

> +    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)
> @@ -4019,17 +4045,7 @@ 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);
>  
>