Re: [PATCH v2] target/s390x: improve cpu compatibility check error message

[Claudio Fontana <cfontana@suse.de>]

On 3/15/24 17:59, Nina Schoetterl-Glausch wrote:
> On Thu, 2024-03-14 at 22:37 +0100, Claudio Fontana wrote:
>> some users were confused by this message showing under TCG:
>>
>> Selected CPU generation is too new. Maximum supported model
>> in the configuration: 'xyz'
>>
>> Clarify that the maximum can depend on the accel, and add a
>> hint to try a different one.
>>
>> Also add a hint for features mismatch to suggest trying
>> different accel, QEMU and kernel versions.
>>
>> Signed-off-by: Claudio Fontana <cfontana@suse.de>
> 
> Reviewed-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
> 
>> ---
>>  target/s390x/cpu_models.c | 22 +++++++++++++++-------
>>  1 file changed, 15 insertions(+), 7 deletions(-)
>>
>> diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
>> index 1a1c096122..8ed3bb6a27 100644
>> --- a/target/s390x/cpu_models.c
>> +++ b/target/s390x/cpu_models.c
>> @@ -500,6 +500,16 @@ static void error_prepend_missing_feat(const char *name, void *opaque)
>>      error_prepend((Error **) opaque, "%s ", name);
>>  }
>>  
>> +static void check_compat_model_failed(Error **errp,
>> +                                      const S390CPUModel *max_model,
>> +                                      const char *msg)
>> +{
>> +    error_setg(errp, "%s. Maximum supported model in the current configuration: \'%s\'",
>> +               msg, max_model->def->name);
>> +    error_append_hint(errp, "Consider a different accelerator, try \"-accel help\"\n");
>> +    return;
>> +}
>> +
>>  static void check_compatibility(const S390CPUModel *max_model,
>>                                  const S390CPUModel *model, Error **errp)
>>  {
>> @@ -507,15 +517,11 @@ static void check_compatibility(const S390CPUModel *max_model,
>>      S390FeatBitmap missing;
>>  
>>      if (model->def->gen > max_model->def->gen) {
>> -        error_setg(errp, "Selected CPU generation is too new. Maximum "
>> -                   "supported model in the configuration: \'%s\'",
>> -                   max_model->def->name);
>> +        check_compat_model_failed(errp, max_model, "Selected CPU generation is too new");
>>          return;
>>      } else if (model->def->gen == max_model->def->gen &&
>>                 model->def->ec_ga > max_model->def->ec_ga) {
>> -        error_setg(errp, "Selected CPU GA level is too new. Maximum "
>> -                   "supported model in the configuration: \'%s\'",
>> -                   max_model->def->name);
>> +        check_compat_model_failed(errp, max_model, "Selected CPU GA level is too new");
>>          return;
>>      }
>>  
>> @@ -537,7 +543,9 @@ static void check_compatibility(const S390CPUModel *max_model,
>>      error_setg(errp, " ");
>>      s390_feat_bitmap_to_ascii(missing, errp, error_prepend_missing_feat);
>>      error_prepend(errp, "Some features requested in the CPU model are not "
>> -                  "available in the configuration: ");
>> +                  "available in the current configuration: ");
>> +    error_append_hint(errp,
>> +                      "Consider a different accelerator, QEMU, or kernel version\n");
> 
> If I'm reading the regex right, this ^, a string literal on a separate line, is excluded
> from the line length check.

Thanks, it's very good to know!

Claudio
> 
>>  }
>>  
>>  S390CPUModel *get_max_cpu_model(Error **errp)
>