linux-kernel - Re: [PATCH] kvm/x86/vmx: report KVM_SYSTEM_EVENT

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Message-ID: <20170328114617.zapicqltmtarv4jt@treble>
Date:   Tue, 28 Mar 2017 06:46:17 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     rkrcmar@...hat.com, x86@...nel.org, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Subject: Re: [PATCH] kvm/x86/vmx: report KVM_SYSTEM_EVENT_CRASH on triple
 fault

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