From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:60268)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <cornelia.huck@de.ibm.com>) id 1bP4Ru-0005oX-3q
	for qemu-devel@nongnu.org; Mon, 18 Jul 2016 05:02:54 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <cornelia.huck@de.ibm.com>) id 1bP4Rp-0001yx-US
	for qemu-devel@nongnu.org; Mon, 18 Jul 2016 05:02:49 -0400
Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:61451
	helo=mx0a-001b2d01.pphosted.com)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <cornelia.huck@de.ibm.com>) id 1bP4Rp-0001yt-O4
	for qemu-devel@nongnu.org; Mon, 18 Jul 2016 05:02:45 -0400
Received: from pps.filterd (m0098417.ppops.net [127.0.0.1])
	by mx0a-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id
	u6I8x8IT081151
	for <qemu-devel@nongnu.org>; Mon, 18 Jul 2016 05:02:45 -0400
Received: from e06smtp12.uk.ibm.com (e06smtp12.uk.ibm.com [195.75.94.108])
	by mx0a-001b2d01.pphosted.com with ESMTP id 2482fvxaxc-1
	(version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT)
	for <qemu-devel@nongnu.org>; Mon, 18 Jul 2016 05:02:44 -0400
Received: from localhost
	by e06smtp12.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use
	Only! Violators will be prosecuted
	for <qemu-devel@nongnu.org> from <cornelia.huck@de.ibm.com>;
	Mon, 18 Jul 2016 10:02:42 +0100
Received: from b06cxnps4076.portsmouth.uk.ibm.com
	(d06relay13.portsmouth.uk.ibm.com [9.149.109.198])
	by d06dlp02.portsmouth.uk.ibm.com (Postfix) with ESMTP id 54D9B219005F
	for <qemu-devel@nongnu.org>; Mon, 18 Jul 2016 10:02:02 +0100 (BST)
Received: from d06av09.portsmouth.uk.ibm.com (d06av09.portsmouth.uk.ibm.com
	[9.149.37.250])
	by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with
	ESMTP id u6I92Yfw66650346
	for <qemu-devel@nongnu.org>; Mon, 18 Jul 2016 09:02:34 GMT
Received: from d06av09.portsmouth.uk.ibm.com (localhost [127.0.0.1])
	by d06av09.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with
	ESMTP id u6I92Vik001118
	for <qemu-devel@nongnu.org>; Mon, 18 Jul 2016 03:02:34 -0600
Date: Mon, 18 Jul 2016 11:02:27 +0200
From: Cornelia Huck <cornelia.huck@de.ibm.com>
In-Reply-To: <20160718082955.GA12086@danjae.aot.lge.com>
References: <1468816661-6345-1-git-send-email-namhyung@kernel.org>
	<1468816661-6345-2-git-send-email-namhyung@kernel.org>
	<20160718095439.1eabb340.cornelia.huck@de.ibm.com>
	<20160718082955.GA12086@danjae.aot.lge.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Message-Id: <20160718110227.6ff6d1a2.cornelia.huck@de.ibm.com>
Subject: Re: [Qemu-devel] [PATCH 1/3] virtio: Basic implementation of virtio
 pstore driver
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: Namhyung Kim <namhyung@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>, Paolo Bonzini <pbonzini@redhat.com>, Radim Kr??m???? <rkrcmar@redhat.com>, "Michael S.
	Tsirkin" <mst@redhat.com>, Anthony Liguori <aliguori@amazon.com>, Anton Vorontsov <anton@enomsg.org>, Colin Cross <ccross@android.com>, Kees Cook <keescook@chromium.org>, Tony Luck <tony.luck@intel.com>, Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@kernel.org>, Minchan Kim <minchan@kernel.org>, kvm@vger.kernel.org, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org

On Mon, 18 Jul 2016 17:29:55 +0900
Namhyung Kim <namhyung@kernel.org> wrote:

> On Mon, Jul 18, 2016 at 09:54:39AM +0200, Cornelia Huck wrote:
> > On Mon, 18 Jul 2016 13:37:39 +0900
> > Namhyung Kim <namhyung@kernel.org> wrote:

> > > +#define VIRT_PSTORE_ORDER    2
> > > +#define VIRT_PSTORE_BUFSIZE  (4096 << VIRT_PSTORE_ORDER)
> > 
> > It may make sense to make the size of the buffer configurable through
> > the config space.
> 
> Right.  I'm considering it too, but it needs a buffer larger than
> kmsg_bytes (= 10K) to work properly in the current implementation.  As
> this version is just to verify the idea is sane and useful, I used a
> fixed size buffer.  Will change in the next version.

Sure, that makes sense for a prototype. We can guard any config space
entry with a feature bit, but this one makes sense to add from the
beginning.

> > Speaking of the standard: I think it makes sense to at least reserve a
> > device id for pstore, as the idea is sound. Maybe prepare a patch to
> > the standard as well if you have time?
> 
> I'd love to.  As I mentioned earlier, I don't have enough knowledge in
> this area.  Could you please provide some links about how can I do that?

See the virtio page at OASIS
(https://www.oasis-open.org/committees/tc_home.php?wg_abbrev=virtio)
for a link to our subversion (yes...) repository. Just do two patches:
one to reserve a device id, and one that specifies how device and
driver work. (For examples, look at the proposed device types that have
been posted to the virtualization lists, e.g. virtio-crypto or
virtio-sdm). You just need to be patient, we're currently a bit
stalled...