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Re: [Qemu-devel] [PATCH v8] kvm: notify host when the guest is panicked
From: |
Marcelo Tosatti |
Subject: |
Re: [Qemu-devel] [PATCH v8] kvm: notify host when the guest is panicked |
Date: |
Mon, 13 Aug 2012 17:24:52 -0300 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Mon, Aug 13, 2012 at 01:48:39PM -0600, Eric Blake wrote:
> On 08/13/2012 12:21 PM, Marcelo Tosatti wrote:
> > On Wed, Aug 08, 2012 at 10:43:01AM +0800, Wen Congyang wrote:
> >> We can know the guest is panicked when the guest runs on xen.
> >> But we do not have such feature on kvm.
> >>
> >> Another purpose of this feature is: management app(for example:
> >> libvirt) can do auto dump when the guest is panicked. If management
> >> app does not do auto dump, the guest's user can do dump by hand if
> >> he sees the guest is panicked.
> >>
> >> We have three solutions to implement this feature:
> >> 1. use vmcall
> >> 2. use I/O port
> >> 3. use virtio-serial.
> >>
> >> We have decided to avoid touching hypervisor. The reason why I choose
> >> choose the I/O port is:
> >> 1. it is easier to implememt
> >> 2. it does not depend any virtual device
> >> 3. it can work when starting the kernel
> >
> > How about searching for the "Kernel panic - not syncing" string
> > in the guests serial output? Say libvirtd could take an action upon
> > that?
> >
> > Advantages:
> > - It works for all architectures.
> > - It does not depend on any virtual device.
>
> But it _does_ depend on a serial console,
Which already exists and is supported.
> and furthermore requires
> libvirt to tee the serial console (right now, libvirt can treat the
> console as an opaque pass-through to the end user, but if you expect
> libvirt to parse the serial console for a particular string, you've lost
> some efficiency).
>
> > - It works as early as serial console output does (panics before
> > that should be rare).
> > - It allows you to see why the guest panicked.
>
> I think your arguments for a serial console have already been made and
> refuted in earlier versions of this patch series, which is WHY this
> series is still applicable.
Refuted why, exactly? Efficiency to parse serial console output in
libvirt should not be a major issue surely?
Either way:
The device should be arch independent, as "panic" is not specific
to a particular architecture. For example virtio which would also work
on S390.
Custom IO port == virtual device, so that depends on virtual
device already.
- [Qemu-devel] [PATCH v8 2/6] kvm: Update kernel headers, (continued)
- [Qemu-devel] [PATCH v8 2/6] kvm: Update kernel headers, Wen Congyang, 2012/08/07
- [Qemu-devel] [PATCH v8 3/6] add a new runstate: RUN_STATE_GUEST_PANICKED, Wen Congyang, 2012/08/07
- [Qemu-devel] [PATCH v8 4/6] add a new qevent: QEVENT_GUEST_PANICKED, Wen Congyang, 2012/08/07
- [Qemu-devel] [PATCH v8 5/6] introduce a new qom device to deal with panicked event, Wen Congyang, 2012/08/07
- [Qemu-devel] [PATCH v8 6/6] allower the user to disable pv event support, Wen Congyang, 2012/08/07
- Re: [Qemu-devel] [PATCH v8] kvm: notify host when the guest is panicked, Andrew Jones, 2012/08/08
- Re: [Qemu-devel] [PATCH v8] kvm: notify host when the guest is panicked, Marcelo Tosatti, 2012/08/13
Re: [Qemu-devel] [PATCH v8] kvm: notify host when the guest is panicked, Daniel P. Berrange, 2012/08/14
- Re: [Qemu-devel] [PATCH v8] kvm: notify host when the guest is panicked, Jan Kiszka, 2012/08/14
- Re: [Qemu-devel] [PATCH v8] kvm: notify host when the guest is panicked, Yan Vugenfirer, 2012/08/14
- Re: [Qemu-devel] [PATCH v8] kvm: notify host when the guest is panicked, Jan Kiszka, 2012/08/14
- Re: [Qemu-devel] [PATCH v8] kvm: notify host when the guest is panicked, Marcelo Tosatti, 2012/08/14
- Re: [Qemu-devel] [PATCH v8] kvm: notify host when the guest is panicked, Anthony Liguori, 2012/08/14
- Re: [Qemu-devel] [PATCH v8] kvm: notify host when the guest is panicked, Marcelo Tosatti, 2012/08/14