From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH qemu-kvm] Add raw(af_packet) network backend to qemu Date: Thu, 28 Jan 2010 16:52:26 +0200 Message-ID: <20100128145226.GA10497@redhat.com> References: <4B5F54E8.3080507@codemonkey.ws> <20100127180338.GB13730@redhat.com> <4B6099E0.40101@codemonkey.ws> <201001280912.04809.arnd@arndb.de> <20100128135644.GE3776@redhat.com> <4B619BA1.9010404@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Arnd Bergmann , Sridhar Samudrala , avi@redhat.com, markmc@redhat.com, ogerlitz@voltaire.com, kvm@vger.kernel.org, qemu-devel@vger.kernel.org To: Anthony Liguori Return-path: Received: from mx1.redhat.com ([209.132.183.28]:46613 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753596Ab0A1Ozo (ORCPT ); Thu, 28 Jan 2010 09:55:44 -0500 Content-Disposition: inline In-Reply-To: <4B619BA1.9010404@codemonkey.ws> Sender: kvm-owner@vger.kernel.org List-ID: On Thu, Jan 28, 2010 at 08:13:53AM -0600, Anthony Liguori wrote: > On 01/28/2010 07:56 AM, Michael S. Tsirkin wrote: >>> Now, the most important use case I see for the raw socket interface >>> in qemu is to get vhost-net and the qemu user implementation to >>> support the same feature set. If you ask for a network setup involving >>> a raw socket and vhost-net and the kernel can support raw sockets >>> but for some reason fails to set up vhost-net, you should have a >>> fallback that has the exact same semantics at a possibly significant >>> performance loss. >>> >>> Arnd >>> >> Makes sense. A simple reason you can't do vhost-net would be >> that you are using tcg. >> > > Some good arguments have been raised in this thread. I really don't > like making our security depend on something external to qemu that is > not widely used or understood. > > That said, I'm not seeing a lot of great alternatives. I definitely > like -net socket better than -net raw. In the absence of an > extraordinarily clever solution, I think we may be stuck with doing this. Agreed on all points. > Regards, > > Anthony Liguori