From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:58542)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <lersek@redhat.com>) id 1ZHdod-0005MN-UL
	for qemu-devel@nongnu.org; Tue, 21 Jul 2015 16:07:04 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <lersek@redhat.com>) id 1ZHdoZ-0007Zw-EN
	for qemu-devel@nongnu.org; Tue, 21 Jul 2015 16:07:03 -0400
Received: from mx1.redhat.com ([209.132.183.28]:48743)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <lersek@redhat.com>) id 1ZHdoZ-0007Zp-9N
	for qemu-devel@nongnu.org; Tue, 21 Jul 2015 16:06:59 -0400
References: <1437494626-3773-1-git-send-email-markmb@redhat.com>
	<1437494626-3773-7-git-send-email-markmb@redhat.com>
	<CAJSP0QVhz8ACedDJr1n6h9gkPv693PVXVBVH=wmAJnpZ8roPdQ@mail.gmail.com>
From: Laszlo Ersek <lersek@redhat.com>
Message-ID: <55AEA65B.2000003@redhat.com>
Date: Tue, 21 Jul 2015 22:06:51 +0200
MIME-Version: 1.0
In-Reply-To: <CAJSP0QVhz8ACedDJr1n6h9gkPv693PVXVBVH=wmAJnpZ8roPdQ@mail.gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Subject: Re: [Qemu-devel] [RFC 6/7] Add offset register to fw_cfg DMA
 interface
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Stefan Hajnoczi <stefanha@gmail.com>, =?UTF-8?Q?Marc_Mar=c3=ad?= <markmb@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>, Kevin O'Connor <kevin@koconnor.net>, qemu-devel <qemu-devel@nongnu.org>, Gerd Hoffmann <kraxel@redhat.com>

On 07/21/15 18:26, Stefan Hajnoczi wrote:
> On Tue, Jul 21, 2015 at 5:03 PM, Marc Mar=C3=AD <markmb@redhat.com> wro=
te:
>> Signed-off-by: Marc Mar=C3=AD <markmb@redhat.com>
>> ---
>>  hw/nvram/fw_cfg.c | 19 ++++++++++++++++---
>>  1 file changed, 16 insertions(+), 3 deletions(-)
>=20
> No commit description, no docs/specs/fw_cfg.txt documentation.

Yes, those would be nice.

Also, I think this patch should be squashed into the main fw_cfg patch.

> I understand how the offset is supposed to work, but why is it
> necessary?  No one needed it before so there must be a reason why you
> decided to add it now.

I guess because of
<http://thread.gmane.org/gmane.comp.bios.coreboot.seabios/9496/focus=3D95=
54>.

For me chunked transfers would be important (ie. transfering I+J=3DK byte=
s
from the same fw_cfg file should be possible as two separate accesses,
with I & J sizes), but I believe the offset register would not be
necessary just for that. So I think it's solely directed at Kevin's
feedback (see link above).

Thanks
Laszlo