Re: [Qemu-devel] [PATCH v4 5/9] hw/timer: QOM'ify m48txx_sysbus (pass 2)

[hitmoon <zxq_yx_007@163.com>]

在 2016年02月22日 17:24, Peter Maydell 写道:
> On 22 February 2016 at 09:11, xiaoqiang zhao <zxq_yx_007@163.com> wrote:
>> assign DeviceClass::vmsd instead of using vmstate_register function
>>
>> Signed-off-by: xiaoqiang zhao <zxq_yx_007@163.com>
>> ---
>>   hw/timer/m48t59.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/hw/timer/m48t59.c b/hw/timer/m48t59.c
>> index 3c683aa..b0cf79d 100644
>> --- a/hw/timer/m48t59.c
>> +++ b/hw/timer/m48t59.c
>> @@ -742,8 +742,6 @@ static void m48t59_realize_common(M48t59State *s, Error **errp)
>>           s->wd_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &watchdog_cb, s);
>>       }
>>       qemu_get_timedate(&s->alarm, 0);
>> -
>> -    vmstate_register(NULL, -1, &vmstate_m48t59, s);
>>   }
>>
>>   static void m48t59_isa_realize(DeviceState *dev, Error **errp)
>> @@ -822,6 +820,7 @@ static void m48txx_isa_class_init(ObjectClass *klass, void *data)
>>       dc->realize = m48t59_isa_realize;
>>       dc->reset = m48t59_reset_isa;
>>       dc->props = m48t59_isa_properties;
>> +    dc->vmsd = &vmstate_m48t59;
>>       nc->read = m48txx_isa_read;
>>       nc->write = m48txx_isa_write;
>>       nc->toggle_lock = m48txx_isa_toggle_lock;
>> @@ -866,6 +865,7 @@ static void m48txx_sysbus_class_init(ObjectClass *klass, void *data)
>>       dc->realize = m48t59_realize;
>>       dc->reset = m48t59_reset_sysbus;
>>       dc->props = m48t59_sysbus_properties;
>> +    dc->vmsd = &vmstate_m48t59;
>>       nc->read = m48txx_sysbus_read;
>>       nc->write = m48txx_sysbus_write;
>>       nc->toggle_lock = m48txx_sysbus_toggle_lock;
>> --
>> 2.1.4
>>
> Just noticed this won't work as it is -- the vmstate
> struct is for the M48t59State*, but the ISA and
> Sysbus wrappers have their own structs which are
> what the dc->vmsd will be wanting to operate on.
> You'd need extra VMState structs I think and
> somebody who knows migration better than me to say
> whether that is a migration compat break.
>
> thanks
> -- PMM
It seems that the old code also use the same vmstate structure. Maybe 
it's a common structure which will not be used at the same time.