From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48291) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aVJRn-0005Ct-3S for qemu-devel@nongnu.org; Mon, 15 Feb 2016 08:44:16 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aVJRj-0002sn-Tc for qemu-devel@nongnu.org; Mon, 15 Feb 2016 08:44:15 -0500 Received: from smtp02.citrix.com ([66.165.176.63]:47011) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aVJRj-0002sj-Oc for qemu-devel@nongnu.org; Mon, 15 Feb 2016 08:44:11 -0500 Date: Mon, 15 Feb 2016 13:44:09 +0000 From: Wei Liu Message-ID: <20160215134409.GM8818@citrix.com> References: <20160212191037.GF8818@citrix.com> <3fbbf2a606a14f708655037f5e4fb31e@AMSPEX02CL03.citrite.net> <20160215131621.GL8818@citrix.com> <56C1D391.101@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <56C1D391.101@suse.com> Subject: Re: [Qemu-devel] [Xen-devel] RFC: configuring QEMU virtfs for Xen PV(H) guests List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Juergen Gross Cc: Wei Liu , "qemu-devel@nongnu.org" , Paul Durrant , Stefano Stabellini , "aneesh.kumar@linux.vnet.ibm.com" , Anthony Perard , Xen-devel , "gkurz@linux.vnet.ibm.com" On Mon, Feb 15, 2016 at 02:33:05PM +0100, Juergen Gross wrote: > On 15/02/16 14:16, Wei Liu wrote: > > On Mon, Feb 15, 2016 at 09:07:13AM +0000, Paul Durrant wrote: > >>> > > [...] > >>> # Option 2: Invent a xen-9p device > >>> > >>> Another way of doing it is to expose a dummy xen-9p device, so that we > >>> can use -fsdev XXX -device xen-9p,YYY. This simple device should be > >>> used to capture the parameters like mount_tag and fsdev_id, and then > >>> chained itself to a known location. Later Xen transport can traverse > >>> this known location. This xen-9p device doesn't seem to fit well into > >>> the hierarchy. The best I can think of its parent should be > >>> TYPE_DEVICE. In this case: > >>> > >>> 1. Toolstack arranges some xenstore entries. > >>> 2. Toolstack arranges command line options for QEMU: > >>> -fsdev XXX -device xen-9p,XXX > >>> 3. QEMU starts up in xen-attach mode, scans xenstore for relevant > >>> entries, then traverses the known location. > >>> > >>> Downside: Inventing a dummy device looks suboptimal to me. > > Sorry, didn't notice this thread before. > No need to be sorry. I posted this last Friday night. I wouldn't expect many replies on Monady. > For Xen pvUSB backend in qemu I need a Xen system device acting as > parent for being able to attach/detach virtual USB busses. > > I haven't had time to update my patches for some time, but the patch > for this system device is rather easy. It could be used as a parent > of the xen-9p devices, too. > > I've attached the patch for reference. > Thanks. I will have a look at your patch. Wei.