Re: [virtio-comment] [PATCH 1/1] ccw: ccw payload description

[Rusty Russell <rusty@au1.ibm.com>]

Cornelia Huck <cornelia.huck@de.ibm.com> writes:
> On Tue, 21 Jan 2014 10:37:26 +1030
> Rusty Russell <rusty@au1.ibm.com> wrote:
>
>> Cornelia Huck <cornelia.huck@de.ibm.com> writes:
>> > On Mon, 20 Jan 2014 11:17:17 +0200
>> > "Michael S. Tsirkin" <mst@redhat.com> wrote:
>> >
>> >> On Mon, Jan 20, 2014 at 02:28:00PM +1030, Rusty Russell wrote:
>> >> > We'll just have to live with the lack of padding, and let's try not to
>> >> > add any more packed-requiring structures.  If we deprecate
>> >> > virtio-balloon, the rest will be contained in CCW.
>> >> > 
>> >> > Cheers,
>> >> > Rusty.
>> >> 
>> >> For CCW, how about my idea of adding optional padding explicitly?
>> >> In the compatibility section, we can explicitly specify the
>> >> the length.
>> >> Drivers can use offsetof(padding) and avoid packed attribute.
>> >
>> > Since Rusty does not like the tables, this looks like a good idea.
>> 
>> Surely making the padding optional makes it more complex, for no real
>> gain?  It's not that much simpler in practice, is it?
>> 
>> This patch just removes the __attribute__((packed)) where it's useless,
>> and notes explicitly where it's required:
>
> (...)
>
> Do we want to go the route of this patch now, together with my
> clarifications in
> https://lists.oasis-open.org/archives/virtio-comment/201401/msg00034.html ?

It's not quite a trivial change, and I know there's some debate.  So
I've created an issue for it (VIRTIO-56), and we can discuss next
meeting.

Thanks,
Rusty.