On Mon, May 30, 2011 at 06:19:14PM +0300, Avi Kivity wrote: > On 05/30/2011 06:15 PM, Jan Kiszka wrote: > >On 2011-05-30 17:10, Roedel, Joerg wrote: > >> On Mon, May 30, 2011 at 11:04:02AM -0400, Jan Kiszka wrote: > >>> On 2011-05-30 16:38, Nadav Har'El wrote: > >>>> On Mon, May 30, 2011, Jan Kiszka wrote about "drop -enable-nesting (was: [PATCH 3/7] cpu model bug fixes and definition corrections...)": > >>>>> On 2011-05-30 10:18, Roedel, Joerg wrote: > >>>>>> On Sat, May 28, 2011 at 04:39:13AM -0400, Jan Kiszka wrote: > >>>>>> > >>>>>>> Jïrg, how to deal with -enable-nesting in qemu-kvm to align behavior > >>>>>>> with upstream? > >>>>>> > >>>>>> My personal preference is to just remove it. In upstream-qemu it is > >>>>>> enabled/disabled by +/-svm. -enable-nesting is just a historic thing > >>>>>> which can be wiped out. > >>>> > >>>> "-enable-nesting" could remain as a synonym for enabling either VMX or SVM > >>>> in the guest, depending on what was available in the host (because KVM now > >>>> supports both nested SVM and nested VMX, but not SVM-on-VMX or vice versa). > >>> > >>> Why? Once nesting is stable (I think SVM already is), there is no reason > >>> for an explicit enable. And you can always mask it out via -cpu. > >>> > >>> BTW, what are the defaults for SVM right now in qemu-kvm and upstream? > >>> Enable if the modeled CPU supports it? > >> > >> qemu-kvm still needs -enable-nesting, otherwise it is disabled. Upstream > >> qemu should enable it unconditionally (can be disabled with -cpu ,-svm). > > > >Then let's start with aligning qemu-kvm defaults to upstream? I guess > >that's what the diff I was citing yesterday is responsible for. > > > >In the same run, -enable-nesting could dump a warning on the console > >that this switch is obsolete and will be removed from future versions. > > I think it's safe to drop -enable-nesting immediately. Dan, does > libvirt make use of it? Yes, but it should be safe to drop it. Currently, if the user specifies a CPU with the 'svm' flag present in libvirt guest XML, then we will pass args '-cpu ....+svm -enable-nesting'. So if we drop --enable-nesting, then libvirt will simply omit it and everything should still work because we have still got +svm set. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
