From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([208.118.235.92]:56916)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <agraf@suse.de>) id 1UCvDo-0008H7-Td
	for qemu-devel@nongnu.org; Tue, 05 Mar 2013 12:00:18 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <agraf@suse.de>) id 1UCvDj-00068r-0S
	for qemu-devel@nongnu.org; Tue, 05 Mar 2013 12:00:12 -0500
Received: from cantor2.suse.de ([195.135.220.15]:50470 helo=mx2.suse.de)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <agraf@suse.de>) id 1UCv2u-00022q-Jy
	for qemu-devel@nongnu.org; Tue, 05 Mar 2013 11:48:56 -0500
Message-ID: <513621F7.9030403@suse.de>
Date: Tue, 05 Mar 2013 17:48:55 +0100
From: Alexander Graf <agraf@suse.de>
MIME-Version: 1.0
References: <1360108037-9211-1-git-send-email-jlarrew@linux.vnet.ibm.com>
	<1360108037-9211-3-git-send-email-jlarrew@linux.vnet.ibm.com>
In-Reply-To: <1360108037-9211-3-git-send-email-jlarrew@linux.vnet.ibm.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [PATCH 2/3] hw/virtio-net.c: set config size using
 host features
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: Jesse Larrew <jlarrew@linux.vnet.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>, aliguori@us.ibm.com, qemu-devel@nongnu.org

On 02/06/2013 12:47 AM, Jesse Larrew wrote:
> Currently, the config size for virtio devices is hard coded. When a new
> feature is added that changes the config size, drivers that assume a static
> config size will break. For purposes of backward compatibility, there needs
> to be a way to inform drivers of the config size needed to accommodate the
> set of features enabled.
>
> Signed-off-by: Jesse Larrew<jlarrew@linux.vnet.ibm.com>

The following patch gets my s390 virtio guest working again, but I doubt 
it's the right fix.

What is the expected dependency chain of feature calls?


Alex

diff --git a/hw/s390x/s390-virtio-bus.c b/hw/s390x/s390-virtio-bus.c
index 089ed92..81be971 100644
--- a/hw/s390x/s390-virtio-bus.c
+++ b/hw/s390x/s390-virtio-bus.c
@@ -154,7 +154,7 @@ static int s390_virtio_net_init(VirtIOS390Device *dev)
      VirtIODevice *vdev;

      vdev = virtio_net_init((DeviceState *)dev, &dev->nic, &dev->net,
-                           dev->host_features);
+                           dev->host_features | (1 << VIRTIO_NET_F_MAC));
      if (!vdev) {
          return -1;
      }