From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40652) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YHCHj-00016G-LX for qemu-devel@nongnu.org; Fri, 30 Jan 2015 09:11:00 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YHCHg-0003qj-AW for qemu-devel@nongnu.org; Fri, 30 Jan 2015 09:10:59 -0500 Received: from e06smtp17.uk.ibm.com ([195.75.94.113]:45397) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YHCHf-0003qf-Ln for qemu-devel@nongnu.org; Fri, 30 Jan 2015 09:10:55 -0500 Received: from /spool/local by e06smtp17.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 30 Jan 2015 14:10:54 -0000 Received: from b06cxnps4075.portsmouth.uk.ibm.com (d06relay12.portsmouth.uk.ibm.com [9.149.109.197]) by d06dlp01.portsmouth.uk.ibm.com (Postfix) with ESMTP id 41A8A17D8059 for ; Fri, 30 Jan 2015 14:10:58 +0000 (GMT) Received: from d06av04.portsmouth.uk.ibm.com (d06av04.portsmouth.uk.ibm.com [9.149.37.216]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t0UEAq0i56426700 for ; Fri, 30 Jan 2015 14:10:52 GMT Received: from d06av04.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av04.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t0UEApdF014794 for ; Fri, 30 Jan 2015 07:10:51 -0700 Date: Fri, 30 Jan 2015 15:10:49 +0100 From: Cornelia Huck Message-ID: <20150130151049.2e4c5331.cornelia.huck@de.ibm.com> In-Reply-To: <20150107191144.GC8734@redhat.com> References: <1418304322-7546-1-git-send-email-cornelia.huck@de.ibm.com> <1418304322-7546-20-git-send-email-cornelia.huck@de.ibm.com> <20141228102446.GA9260@redhat.com> <20150107172949.11f374bf.cornelia.huck@de.ibm.com> <20150107191144.GC8734@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH RFC v6 19/20] virtio-blk: revision specific feature bits List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: thuth@linux.vnet.ibm.com, rusty@rustcorp.com.au, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org On Wed, 7 Jan 2015 21:11:44 +0200 "Michael S. Tsirkin" wrote: > On Wed, Jan 07, 2015 at 05:29:49PM +0100, Cornelia Huck wrote: > > On Sun, 28 Dec 2014 12:24:46 +0200 > > "Michael S. Tsirkin" wrote: > > > > > On Thu, Dec 11, 2014 at 02:25:21PM +0100, Cornelia Huck wrote: > > > > Wire up virtio-blk to provide different feature bit sets depending > > > > on whether legacy or v1.0 has been requested. > > > > > > > > Note that VERSION_1 is still disabled due to missing ANY_LAYOUT support. > > > > > > > > Signed-off-by: Cornelia Huck > > > > > > So we need some way for devices to tell transports > > > not to negotiate rev 1. > > > Does clearing VERSION_1 have this effect? > > > > > I just noticed that my patch is running in circles here. > > > > What we need is probably the transport-dependent maximum revision > > checker (which at least for ccw is acting on a device) pass in the > > requested revision and check if the feature bits for the revision > > include VERSION_1. Does that make sense? > > Just make devices set 'rev 1 supported' flag? I'm now using the ->get_features() callback to check for VERSION_1 (assuming every device that supports it adds the bit in its callback) and only allow rev 1 if it is present. Will play with this a bit as well.