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

Il 21/08/2013 18:55, Daniel P. Berrange ha scritto: > 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. So are you suggesting to add a <pvpanic/> element to <devices>? That may be fine, but it doesn't seem very user-friendly.