On Tue, Aug 06, 2013 at 10:45:01AM +0200, Andreas Färber wrote: > Am 06.08.2013 10:36, schrieb Gleb Natapov: > > On Tue, Aug 06, 2013 at 11:33:10AM +0300, Michael S. Tsirkin wrote: > >> On Tue, Aug 06, 2013 at 10:21:52AM +0300, Gleb Natapov wrote: > >>>> If you see a mouse in a room, how likely is it that there's > >>>> a single mouse there? > >>>> > >>>> This is a PV technology which to me looks like it was > >>>> rushed through and not only set on by default, but > >>>> without a way to disable it - apparently on the assumption > >>>> there's 0 chance it can cause any damage. Now that > >>>> we do know the chance it's not there, why not go back > >>>> to the standard interface, and why not give > >>>> users a chance to enable/disable it? > >>> You should be able to disable it with: -device pvpanic,ioport=0 > >> > >> Doesn't work for me. > > Bug that should be fixed. With this command line _STA should return > > zero. > > > >> Besides, both -device pvpanic and use of ioport=0 to disable it > >> are completely undocumented. > >> > > Not the only undocumented thing in QEMU command line :) > [snip] > > I disagree: -device adds a device, not removes one. It will still be > present. > > I am neutral as to whether qemu-system-x86_64 should have it enabled by > default or not. But if we want to suppress it, then -nodefaults should > disable it. Since libvirt uses that though, it would mean libvirt would > need to add it back, whether via user's XML domain config or by libvirt > itself based on some version/etc. heuristics. > > Andreas
Do you agree that this (-nodefaults does not have pvpanic device by default, -device pvpanic adds it) makes more sense than the proposed alternative: -nodefaults has pvpanic unless an old -M type is specified, ioport=0 removes the device? > -- > SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany > GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg
