Re: [Xen-devel] [PATCH v4 11/16] xen/arm: calculate vgic irq rank based on register size

[Vijay Kilari <vijay.kilari@xxxxxxxxx>]

On Fri, May 30, 2014 at 3:28 PM, Julien Grall <julien.grall@xxxxxxxxxx> wrote:
> Hi Vijay,
>
>>>>
>>>>       case GICD_ISENABLER ... GICD_ISENABLERN:
>>>> -        if ( dabt.size != 2 ) goto bad_width;
>>>> -        rank = vgic_irq_rank(v, 1, gicd_reg - GICD_ISENABLER);
>>>> +        if ( dabt.size != DABT_WORD ) goto bad_width;
>>>> +        rank = vgic_irq_rank(v, 1, gicd_reg - GICD_ISENABLER,
>>>> DABT_WORD);
>>>
>>>
>>> In your commit message you explicitly say that use DABT_* will help you
>>> to get the register offset but... you still hardcode the size.
>>>
>>> Why can't you use dabt.size here? And all the other places.
>>
>>
>>     dabt.size gives the current register access size but not the actual
>> register size.
>
>
> In this specific case, the register access size and the actual register size
> is the same...

Yes, in most of the cases it is same. But there are some register
access that supports
both byte and word size access. In that case we have to choose always
the register size DABT_*

To be consistent I have not used dabt.size.  In case if byte access to
particular register
is added then one can go wrong.

>
> Regards,
>
> --
> Julien Grall

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