From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58452) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bmy4Y-0003Ep-I6 for qemu-devel@nongnu.org; Thu, 22 Sep 2016 03:05:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bmy4T-00084c-Mg for qemu-devel@nongnu.org; Thu, 22 Sep 2016 03:05:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39898) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bmy4T-00084N-GW for qemu-devel@nongnu.org; Thu, 22 Sep 2016 03:05:25 -0400 References: <1473750714-48290-1-git-send-email-aik@ozlabs.ru> <67d4a40e-420f-f9b0-a499-0ca385e93f2e@redhat.com> <062ab708-1616-561c-5606-25042949597f@ozlabs.ru> <81194f18-3bc8-a134-5b32-84690f2d9863@redhat.com> From: Jason Wang Message-ID: Date: Thu, 22 Sep 2016 15:05:17 +0800 MIME-Version: 1.0 In-Reply-To: <81194f18-3bc8-a134-5b32-84690f2d9863@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH qemu v2] tap: Allow specifying a bridge List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini , Alexey Kardashevskiy , qemu-devel@nongnu.org On 2016=E5=B9=B409=E6=9C=8819=E6=97=A5 19:59, Paolo Bonzini wrote: > > On 19/09/2016 02:33, Alexey Kardashevskiy wrote: >> On 15/09/16 07:04, Paolo Bonzini wrote: >>> >>> On 13/09/2016 09:11, Alexey Kardashevskiy wrote: >>>> The tap backend is already using qemu-bridge-helper to attach tap >>>> interface to a bridge but (unlike the bridge backend) it always uses >>>> the default bridge name - br0. >>>> >>>> This adds a "br" property support to the tap backend. >>>> >>>> Signed-off-by: Alexey Kardashevskiy >>> Stupid question ahead: how does -netdev bridge compare to -netdev tap >>> after this patch? Is there a case left where you must use -netdev br= idge? >>> >>> Or can we make -netdev bridge a synonym for "-netdev >>> tap,helper=3D/default/path/to/helper"? >> I looked through history but I could not understand why "bridge" was >> introduced in the first place as even there (a7c36ee4920ea) is an exam= ple of >> >> -netdev tap,helper=3D"/usr/local/libexec/qemu-bridge-helper --br=3Dqem= ubr0",id=3Dhn0 >> >> so it was assumed even then that people might want tap on a specific b= ridge. >> >> So my stupid question is - what do I have to do to get this accepted >> (besides a note that it is 2.8+) or it is not interesting to anyone? := ) > I think the patch is even more interesting because it lets us simplify > the code for -netdev bridge. > > Paolo > According to http://wiki.qemu.org/Features-Done/HelperNetworking. Looks=20 like this allows creating a third party backend without modifying qemu.=20 And the bridge helper is an example for this.