From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:52943) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UZh5I-0002QI-3w for qemu-devel@nongnu.org; Tue, 07 May 2013 08:33:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UZh5F-0002rQ-7x for qemu-devel@nongnu.org; Tue, 07 May 2013 08:33:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:62467) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UZh5E-0002rK-Vm for qemu-devel@nongnu.org; Tue, 07 May 2013 08:33:29 -0400 Date: Tue, 7 May 2013 15:33:13 +0300 From: "Michael S. Tsirkin" Message-ID: <20130507123313.GC21361@redhat.com> References: <20130507102223.GA16878@redhat.com> <5188F3B2.2040109@greensocs.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <5188F3B2.2040109@greensocs.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH] virtio-net: require that config size is initialized List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: KONRAD =?iso-8859-1?Q?Fr=E9d=E9ric?= Cc: Peter Maydell , Anthony Liguori , Jason Wang , qemu-devel@nongnu.org, Stefan Hajnoczi , Paolo Bonzini On Tue, May 07, 2013 at 02:29:38PM +0200, KONRAD Fr=E9d=E9ric wrote: > Hi, >=20 > I think it is not a good idea, as we wanted to make VirtIODevice > hot-pluggable for virtio-mmio. And then this hack will break cross version migration. > Maybe we can use a callback which is called by virtio-bus before > plugging, to ensure that this > config size is computed? OK, will you post such a patch? > On 07/05/2013 12:22, Michael S. Tsirkin wrote: > >All buses do this, and if they don't they get subtle > >bugs related to cross version migration. > >Let's add an assert to catch these bugs early. > > > >Signed-off-by: Michael S. Tsirkin > >--- > > > >Just a cleanup so not 1.5 material. > >Seems to work fine here - any opinions? > > > > hw/net/virtio-net.c | 7 ++++--- > > 1 file changed, 4 insertions(+), 3 deletions(-) > > > >diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > >index 908e7b8..f0a9272 100644 > >--- a/hw/net/virtio-net.c > >+++ b/hw/net/virtio-net.c > >@@ -1282,6 +1282,8 @@ static int virtio_net_device_init(VirtIODevice *= vdev) > > DeviceState *qdev =3D DEVICE(vdev); > > VirtIONet *n =3D VIRTIO_NET(vdev); > >+ /* Verify that config size has been initialized */ > >+ assert(n->config_size !=3D (size_t)-1); > > virtio_init(VIRTIO_DEVICE(n), "virtio-net", VIRTIO_ID_NET, > > n->config_size); > >@@ -1386,10 +1388,9 @@ static void virtio_net_instance_init(Object *ob= j) > > VirtIONet *n =3D VIRTIO_NET(obj); > > /* > >- * The default config_size is sizeof(struct virtio_net_config). > >- * Can be overriden with virtio_net_set_config_size. > >+ * The config_size must be set later with virtio_net_set_config_s= ize. > > */ > >- n->config_size =3D sizeof(struct virtio_net_config); > >+ n->config_size =3D (size_t)-1; > > } > > static Property virtio_net_properties[] =3D {