Re: [PATCH] virtio: Define and use per-architecture "pfn shift" constants

Hollis Blanchard wrote:
> On Thu, 2008-11-06 at 10:49 +0000, Mark McLoughlin wrote:
>   
>> But actually, why do we align the size anyway?
>>     
>
> I assume it's so that the last page in the ring (containing the "used"
> fields) could be safely mapped into another guest's address space,
> without fear of exposing other data.
>
> I don't know how valuable that is, but that's not really my concern so I
> preserved the behavior.
>
>   
>> Also might make sense for vring_init() and vring_size() not to take a
>> pagesize argument and hard-code them to use VRING_PAGE_SIZE.
>>     
>
> I think that's a good idea. Anthony mentioned earlier the code was done
> this way so it could be copied to userspace, where PAGE_SIZE is
> unavailable, but that isn't an issue if we switch to VRING_PAGE_SIZE.
>   

Agreed.

Regards,

Anthony Liguori