Re: [PATCH] kvm/x86/vmx: report KVM_SYSTEM_EVENT_CRASH on triple fault

From: Josh Poimboeuf
Date: Tue Mar 28 2017 - 07:49:03 EST


On Tue, Mar 28, 2017 at 03:51:01AM -0400, Paolo Bonzini wrote:
>
> > While debugging a kernel issue, I found that QEMU always reboots when an
> > x86 triple fault occurs, which complicates debugging. QEMU and libvirt
> > have a facility for creating a dump when KVM reports
> > KVM_SYSTEM_EVENT_CRASH. So change the VMX triple fault handler to do
> > that. This gives user space the ability to decide whether to dump,
> > pause, shutdown, or reboot.
>
> You probably want QEMU's -no-reboot option.
>
> Triple faults are already reported to userspace with KVM_EXIT_SHUTDOWN,
> and it's up to userspace to decide what to do with it. This patch cannot
> be applied, because there are guests that do a triple-fault intentionally
> in order to reset the machine.

Ok. Any idea how to force libvirt to create a dump? It has a
'coredump-destroy' option, but that only seems to work with 'on_crash':

https://libvirt.org/formatdomain.html#elementsEvents

--
Josh