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

[Laszlo Ersek]

On 02/08/16 11:46, Marcel Apfelbaum wrote:
> On 02/08/2016 12:28 PM, Laszlo Ersek wrote:
>> 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).
> 
> Oh, v1->v2 section should be under -- line, I'll resend
> 
>>
>>>   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 <address@hidden>
>>> Signed-off-by: Marcel Apfelbaum <address@hidden>
>>> ---
>>>   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?
> 
> I would have nothing against it, but how can we be sure that opts poins
> to machine opts
> at the time set_machine_options is called? Or I am missing something.

Please search this new function in your text editor for occurrences of
"qemu_get_machine_opts", and you will see. :)

Thanks
Laszlo

> 
>>
>> With that:
>>
>> Reviewed-by: Laszlo Ersek <address@hidden>
> 
> Thanks! Waiting for your comment to the above and I'll post again.
> Marcel
> 
>>
>> 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);
>>>
>>>
>>
>