From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46567) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WmgBa-00070i-6b for qemu-devel@nongnu.org; Tue, 20 May 2014 05:18:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WmgBW-00032H-6v for qemu-devel@nongnu.org; Tue, 20 May 2014 05:18:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55045) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WmgBV-00032C-Ud for qemu-devel@nongnu.org; Tue, 20 May 2014 05:18:10 -0400 Date: Tue, 20 May 2014 10:18:03 +0100 From: "Richard W.M. Jones" Message-ID: <20140520091802.GP1302@redhat.com> References: <1400518826-19144-1-git-send-email-dgilbert@redhat.com> <1400571640.10626.7.camel@nilsson.home.kraxel.org> <20140520084725.GA2538@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140520084725.GA2538@work-vm> Subject: Re: [Qemu-devel] [PATCH] -machine vmport=off: Allow disabling of VMWare ioport emulation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" Cc: mst@redhat.com, armbru@redhat.com, qemu-devel@nongnu.org, Gerd Hoffmann , aliguori@amazon.com, Anthony PERARD On Tue, May 20, 2014 at 09:47:26AM +0100, Dr. David Alan Gilbert wrote: > * Gerd Hoffmann (kraxel@redhat.com) wrote: > > > /* init basic PC hardware */ > > > - pc_basic_device_init(isa_bus, gsi, &rtc_state, &floppy, xen_enabled(), > > > - 0x4); > > > + pc_basic_device_init(isa_bus, gsi, &rtc_state, &floppy, > > > + !qemu_opt_get_bool(qemu_get_machine_opts(), "vmport", > > > + true) || xen_enabled(), 0x4); > > > > pc_basic_device_init > > (isa_bus, gsi, &rtc_state, &floppy, > > !qemu_opt_get_bool(qemu_get_machine_opts(),"vmport",!xen_enabled()), > > 0x4); > > > > ? > > > > This makes vmport switchable on xen too, with traditional behavior being > > the default (off on xen, on otherwise). > > Yes I guess that would work (although documenting it would be a little hairy); > however, does anyone understand the reasons it's disabled in the Xen world? It was disabled in this patch. The commit message is saying that vmport cannot work in Xen, but I'm not exactly clear why. commit 1611977c3d8fdbdac6090cbd1f5555cee4aed6d9 Author: Anthony PERARD Date: Tue May 3 17:06:54 2011 +0100 pc, Disable vmport initialisation with Xen. This is because there is not synchronisation of the vcpu register between Xen and QEMU, so vmport can't work properly. This patch introduces no_vmport parameter to pc_basic_device_init. Signed-off-by: Anthony PERARD Signed-off-by: Alexander Graf Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com Fedora Windows cross-compiler. Compile Windows programs, test, and build Windows installers. Over 100 libraries supported. http://fedoraproject.org/wiki/MinGW