Re: [libvirt] [Qemu-devel] pvpanic device should not be automatically included as an internal device

On 08/01/2013 08:18 AM, Gerd Hoffmann wrote: > On 08/01/13 15:08, Marcel Apfelbaum wrote: >> Hi, >> >> The problem with pvpanic being an internal device is that VMs running >> operating systems without a driver for this device will have problems >> when qemu will be upgraded (from qemu without this pvpanic). >> >> The outcome may be, for example: in Windows(let's say XP) the Device manager >> will open a "new device" wizard and the device will appear as an unrecognized device. > > Only happens when also changing the machine type on upgrade as it is > turned off on old machine types. > > But, yes, pvpanic will show up as "Unknown device" without driver and > with the funky yellow exclamation mark in device manager in windows > guests. Newer windows versions don't kick the "new device" wizard. But > still I have my doubts that it is a good idea to add it unconditionally ... Automatic devices with no command line argument have proven to be a nightmare for libvirt as well. Although the just-released libvirt 1.1.1 now supports the <on_crash> element for controlling the command line parameters of qemu related to how qemu will behave when the pvpanic device is triggered, I would also welcome having the ability to control whether the guest even has a pvpanic device exposed, just as we can control whether a guest has a memballoon device exposed.