Re: [PATCH 2/2 v2] xen: arm: Set all bits in mfn_to_xen_entry()

[Julien Grall <julien.grall@citrix.com>]

On 21/08/2015 12:47, Chris (Christopher) Brand wrote:
> Hi Andrew,
>
>> On 21/08/15 00:33, Chris Brand wrote:
>>> Ensure that every bit has a specific value.
>>>
>>> Reported-by: Julien Grall <julien.grall@citrix.com>
>>> Signed-off-by: Chris Brand <chris.brand@broadcom.com>
>>> ---
>>> v2 adds comments on pxn and avail.
>>
>> This is no functional change, if the compiler is conforming to the C spec.
>>
>> The spec guarantees that structure initialisation like this causes unspecified
>> names to gain their default value.  As these are integer bitfields, the default
>> value is 0.
>>
>> What compiler is in use?  It would appear that it is buggy, or at least has
>> buggy scalar replacement optimisations.
>
> That's right. I'd forgotten about that. This was actually suggested by Julien in
> a review of another patch I sent. I haven't seen any problems this fixes.

I still think those patches are valid in order to know which value are 
set by default and what does it mean.

Regards,

-- 
Julien Grall