From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NJBQu-0006zd-C0 for qemu-devel@nongnu.org; Fri, 11 Dec 2009 14:45:44 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1NJBQp-0006tZ-7Q for qemu-devel@nongnu.org; Fri, 11 Dec 2009 14:45:43 -0500 Received: from [199.232.76.173] (port=34114 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NJBQp-0006tM-0i for qemu-devel@nongnu.org; Fri, 11 Dec 2009 14:45:39 -0500 Received: from mx1.redhat.com ([209.132.183.28]:15769) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1NJBQo-0005es-Ha for qemu-devel@nongnu.org; Fri, 11 Dec 2009 14:45:38 -0500 Subject: Re: [Qemu-devel] Spice project is now open From: Mark McLoughlin In-Reply-To: <4B229FAA.8010606@codemonkey.ws> References: <1393046876.1549021260539141025.JavaMail.root@zmail05.collab.prod.int.phx2.redhat.com> <4B226BFC.1040606@codemonkey.ws> <20091211204828.464707cf@redhat.com> <4B2297A2.8040102@codemonkey.ws> <1260559510.29755.14.camel@blaa> <4B229FAA.8010606@codemonkey.ws> Content-Type: text/plain; charset="UTF-8" Date: Fri, 11 Dec 2009 19:45:33 +0000 Message-Id: <1260560733.29755.20.camel@blaa> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Reply-To: Mark McLoughlin List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Yaniv Kamay , Izik Eidus , qemu-devel@nongnu.org On Fri, 2009-12-11 at 13:38 -0600, Anthony Liguori wrote: > Mark McLoughlin wrote: > > On Fri, 2009-12-11 at 13:04 -0600, Anthony Liguori wrote: > > > >> But to introduce another protocol where a user has to make a choice to > >> use Spice over VNC, I think we need a really good justification for > >> that. It's really about complexity. A user shouldn't have to know > >> about Spice or VNC. They shouldn't have to contemplate the trade-offs > >> of whether their management tool is aware or not. It should Just Work. > >> > > > > That's a good goal. > > > > If we add a new protocol, we could achieve the same thing by allowing > > qemu support both VNC and Spice at runtime. Then you just need a client > > like virt-viewer that can handle both protocols, and old VNC clients > > will continue to be able to connect to newer qemu. > > > > Supporting them at the same time could be potentially challenging. You > would need to render Spice locally in qemu in order to expose it via vnc. > > Another nasty bit is that two protocols mean two different sets of > authentication mechanisms. Does Spice support SASL based > authentication? Could it make sense to essentially tunnel Spice through > vnc in order to reuse the existing authentication infrastructure? I don't doubt there are challenges. I think your requirement that old clients work with new servers and new clients work with old servers is a good one. Maybe extending VNC is the best way to get there, but it should be recognized there is another way of achieving the same thing if Spice does require a new protocol. The underlying goal is getting lost in the "Spice can't be a VNC extension" discussion :-) Cheers, Mark.