From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Stabellini Subject: Re: qemu device model question Date: Tue, 19 May 2015 00:36:49 +0100 Message-ID: References: <55531142.6040304@suse.com> <1431509440.8263.237.camel@citrix.com> <1431943233.4944.24.camel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1431943233.4944.24.camel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: George Dunlap , Anthony Perard , "xen-devel@lists.xensource.com" , Juergen Gross , Stefano Stabellini List-Id: xen-devel@lists.xenproject.org On Mon, 18 May 2015, Ian Campbell wrote: > On Mon, 2015-05-18 at 10:49 +0100, George Dunlap wrote: > > Is there really no way to start up a qdisk process after the domain is > > created? The qdisk process doesn't actually need to do any emulation, > > after all -- it's just acting as a backend, right? > > FWIW xencommons starts a qemu for dom0 using: > $QEMU_XEN -xen-domid 0 -xen-attach -name dom0 -nographic -M xenpv -daemonize \ > -monitor /dev/null -serial /dev/null -parallel /dev/null \ > -pidfile $QEMU_PIDFILE > > I'd be surprised if this didn't also work for an arbitrary PV domain and > I assume it wouldn't be needed for an HVM one. It doesn't work for HVM guests because the QEMU device model also runs a qdisk backend instance. However it could work for PV/PVH guests. FYI I am working on a set of patches to remove the handling of PV backends from QEMU device model. it requires both QEMU and libxl changes. Once they are in, you'll be able to do this for HVM guests too.