From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NJ7sd-0003by-Ko for qemu-devel@nongnu.org; Fri, 11 Dec 2009 10:58:07 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1NJ7sX-0003Um-F9 for qemu-devel@nongnu.org; Fri, 11 Dec 2009 10:58:06 -0500 Received: from [199.232.76.173] (port=39486 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NJ7sX-0003Ud-BD for qemu-devel@nongnu.org; Fri, 11 Dec 2009 10:58:01 -0500 Received: from mail-qy0-f179.google.com ([209.85.221.179]:60482) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1NJ7sW-0006Xg-LP for qemu-devel@nongnu.org; Fri, 11 Dec 2009 10:58:01 -0500 Received: by qyk9 with SMTP id 9so574980qyk.30 for ; Fri, 11 Dec 2009 07:57:54 -0800 (PST) Message-ID: <4B226BFC.1040606@codemonkey.ws> Date: Fri, 11 Dec 2009 09:57:48 -0600 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] Spice project is now open References: <1393046876.1549021260539141025.JavaMail.root@zmail05.collab.prod.int.phx2.redhat.com> In-Reply-To: <1393046876.1549021260539141025.JavaMail.root@zmail05.collab.prod.int.phx2.redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Yaniv Kamay Cc: qemu-devel@nongnu.org Yaniv Kamay wrote: > Hi, > > Spice project is now open, for more information visit http://spice-space.org, > due to a server relocation the site will be down during this weekend. > > Spice ship patched QEMU based on fairly old KVM snapshot as a reference > implementation. The Spice team plane to push all the relevant bits into > QEMU upstream. > Historically, we have not supported multiple display mechanisms favoring making one mechanism as good as it can be. Supporting both Spice and VNC would go against this policy. It's not outside the realm of possibility, but there has to be a good justification for it. We need to separate the advantages of having a paravirtual display driver from the advantages of a remote display protocol. For instance, VNC is capable of doing ARGB cursor offloading to the client. We do not support it in QEMU because the VGA drivers we emulate do not support this functionality. Likewise, VNC can support sound tunneling and QEMU does implement this (although virt-manager does not yet). So from a protocol perspective, what are the advantages of Spice over VNC? Obviously, the disadvantages are that for all practical purposes, it's a closed protocol. While there is now a specification, there is not a clear mechanism for extending it by third parties. VNC has a published protocol and there's a documented process for extending by third parties. There are a large number of existing VNC clients so from an interoperability perspective, VNC clearly wins. Since VNC is extensible (and we've extended it many times for QEMU), if Spice possesses unique encoding mechanisms that are advantageous, why wouldn't we just add those mechanisms to VNC as an extension? Regards, Anthony Liguori