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

[Marcel Apfelbaum <marcel@redhat.com>]

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 <mst@redhat.com>
>> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
>> Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
>> ---
>>
>> 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

>