Re: [PATCH v3 15/17] hw/microblaze: Support various endianness for s3adsp1800 machines

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 11/11/24 07:56, Thomas Huth wrote:
> On 08/11/2024 16.43, Philippe Mathieu-Daudé wrote:
>> Introduce an abstract machine parent class which defines
>> the 'little_endian' property. Duplicate the current machine,
>> which endian is tied to the binary endianness, to one big
>> endian and a little endian machine; updating the machine
>> description. Keep the current default machine for each binary.
>>
>> 'petalogix-s3adsp1800' machine is aliased as:
>> - 'petalogix-s3adsp1800-be' on big-endian binary,
>> - 'petalogix-s3adsp1800-le' on little-endian one.
>>
>> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>> ---
>>   hw/microblaze/petalogix_s3adsp1800_mmu.c | 62 +++++++++++++++++++-----
>>   1 file changed, 51 insertions(+), 11 deletions(-)
> ...
>>   static const TypeInfo petalogix_s3adsp1800_machine_types[] = {
>>       {
>>           .name           = TYPE_PETALOGIX_S3ADSP1800_MACHINE,
>>           .parent         = TYPE_MACHINE,
>> -        .class_init     = petalogix_s3adsp1800_machine_class_init,
>> +        .abstract       = true,
>> +        .class_size     = sizeof(PetalogixS3adsp1800MachineClass),
>> +    },
>> +    {
>> +        .name           = MACHINE_TYPE_NAME("petalogix-s3adsp1800-be"),
>> +        .parent         = TYPE_PETALOGIX_S3ADSP1800_MACHINE,
>> +        .class_init     = petalogix_s3adsp1800_machine_class_init_be,
>> +    },
>> +    {
>> +        .name           = MACHINE_TYPE_NAME("petalogix-s3adsp1800-le"),
>> +        .parent         = TYPE_PETALOGIX_S3ADSP1800_MACHINE,
>> +        .class_init     = petalogix_s3adsp1800_machine_class_init_le,
>>       },
>>   };
> 
> Do we really want additional machine types for this? Can't we simply let 
> the user set the machine property instead? (otherwise, all tests that 
> run for each machine types (see qtest_cb_for_every_machine) will now be 
> executed three times instead of only once). IMHO it should be sufficient 
> to have a machine property for this and add proper documentation for the 
> machine.

Machine property was my first approach but then I figured when merging
the 2 binaries in one, it is confusing for the CLI users.

Having 3 more tests until we unify the endianness binary doesn't seem
a high price to pay to me. Besides, not we are not exercising the same
code path. We need to prove the tests are really duplicated so we can
merge the binaries. If you really insist I can modify qtests to skip
these machines meanwhile.

> 
>   Thomas
>