Re: [libvirt] [RFC PATCH v2 0/3] Start fixing the pvpanic mess

On Wed, Aug 21, 2013 at 06:51:11PM +0200, Paolo Bonzini wrote: > Il 21/08/2013 18:48, Daniel P. Berrange ha scritto: >> No, <on_crash> is the right thing to be using for this from >> libvirt's pov & I don't think we should invent something new. >> The <on_crash> element has always been intended to represent >> handling of guest panics, not qemu internal errors. > > Actually for Xen HVM guests, it mostly traps things such as failed > vmentries. The Xen PV-on-HVM drivers do not register a panic notifier > that moves the guest to the "crashed" state. > > <on_crash> cannot be salvaged, in my opinion, because all domain XMLs in > the wild will have a setting that causes libvirt to add "-device > isa-pvpanic". Thus changing libvirt versions will change guest > hardware, which is _very_ bad. > > In addition, Windows XP and 2003 will show the annoying device wizard > upon a libvirt upgrade, and fixing this is what surfaced all the mess. The existance of a <on_crash> element should not be having any effect on what hardware we create. That is merely a lifecycle policy setting that should be completely independant of the guest device model. eg it is valid to have <on_crash> present in the XML at all times, even if there's no pvpanic device present. That simply means the actions will never be triggered.