On Wed, 15 Feb 2012 11:00:25 +0000 "Daniel P. Berrange" <berrange@xxxxxxxxxx> wrote: > On Wed, Feb 15, 2012 at 02:44:18PM +0800, Wen Congyang wrote: > > Hi all: > > > > If the guest runs on xen, we can know the guest OS paniced, and the guest status > > is paniced. But if the guest runs on qemu/kvm, we need the same feature. And the > > feature to know guest-is-panic is a very very good feature for enterprise. > > > > We have some ways to know that guest has paniced: > > 1. watchdog timeouts > > It is not a good way, because we can not say "the guest is paniced" in 100% accuracy > > 2. use a PV driver(like the XEN) > > The old RHELs do not have such driver... > > It can not work for the second kernel... > > 3. Adding a function for console-logging (in ring buffer or some) and check messages > > given by guests. If we allow some filtering script or some, we can catch Linux's > > panic messages. We can say the guest paniced if we catch such messages. We may be > > able to catch other events by other script > > > > I prefer to 3 now. Does anyone have a better idea? > > I have discussed this with Anthony before and the thought was that QEMU/KVM > should provide some kind of paravirtualized crash notification service to > the guest. ie option 2. such a device would likely be quite simple and > thus possible to backport to older kernels as needed > AFAIK, linux kernel has notifier at panic but it doesn't work if kdump is enabled. And IIRC, There was a discussion in lkml that any modules should not be called when crash_kexec() is called. So, no chance to notify it from the module in the 1st kernel, now. Calling it from 2nd kernel will work but the bahavior will be different from non-kdump guest. Can't we do notify by hypercall ? But this will require guest modification.. Thanks, -Kame -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list