Re: [Qemu-devel] [PATCH for-4.1? 1/2] stellaris_input: Fix vmstate description of buttons field

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 7/25/19 7:02 PM, Dr. David Alan Gilbert wrote:
> * Peter Maydell (peter.maydell@linaro.org) wrote:
>> gamepad_state::buttons is a pointer to an array of structs,
>> not an array of structs, so should be declared in the vmstate
>> with VMSTATE_STRUCT_VARRAY_POINTER_INT32; otherwise we
>> corrupt memory on incoming migration.
>>
>> We bump the vmstate version field as the easiest way to
>> deal with the migration break, since migration wouldn't have
>> worked reliably before anyway.
>>
>> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> 
> OK, it would be great to change num_buttons to uint32_t and make that a
> UINT32 at some point;  it's hard to press negative buttons.

Since the version is incremented, now seems to be a good time.

> 
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> 
>> ---
>>  hw/input/stellaris_input.c | 10 ++++++----
>>  1 file changed, 6 insertions(+), 4 deletions(-)
>>
>> diff --git a/hw/input/stellaris_input.c b/hw/input/stellaris_input.c
>> index 20c87d86f40..3a666d61d47 100644
>> --- a/hw/input/stellaris_input.c
>> +++ b/hw/input/stellaris_input.c
>> @@ -60,12 +60,14 @@ static const VMStateDescription vmstate_stellaris_button = {
>>  
>>  static const VMStateDescription vmstate_stellaris_gamepad = {
>>      .name = "stellaris_gamepad",
>> -    .version_id = 1,
>> -    .minimum_version_id = 1,
>> +    .version_id = 2,
>> +    .minimum_version_id = 2,
>>      .fields = (VMStateField[]) {
>>          VMSTATE_INT32(extension, gamepad_state),
>> -        VMSTATE_STRUCT_VARRAY_INT32(buttons, gamepad_state, num_buttons, 0,
>> -                              vmstate_stellaris_button, gamepad_button),
>> +        VMSTATE_STRUCT_VARRAY_POINTER_INT32(buttons, gamepad_state,
>> +                                            num_buttons,
>> +                                            vmstate_stellaris_button,
>> +                                            gamepad_button),
>>          VMSTATE_END_OF_LIST()
>>      }
>>  };
>> -- 
>> 2.20.1
>>
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
>