Re: [Qemu-devel] [PATCH v2 1/4] vl.c: Fix regression in machine error message

[Markus Armbruster <armbru@redhat.com>]

Eduardo Habkost <ehabkost@redhat.com> writes:

> From: Marcel Apfelbaum <marcel@redhat.com>
>
> 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 <mst@redhat.com>
> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
> Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
> Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
>  vl.c | 37 ++++++++++++++++++++++++++-----------
>  1 file changed, 26 insertions(+), 11 deletions(-)
>
> diff --git a/vl.c b/vl.c
> index 175ebcc..afbf13f 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)
> @@ -4030,17 +4055,7 @@ 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);

Style nit: I'd prefer

    machine_class = parse_machine_options();

Can convert to that when I apply to error-next.

>  
>      set_memory_options(&ram_slots, &maxram_size, machine_class);