lkml.org 
[lkml]   [2012]   [Aug]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [Qemu-devel] [PATCH v8] kvm: notify host when the guest is panicked
    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, 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.

    --
    Eric Blake eblake@redhat.com +1-919-301-3266
    Libvirt virtualization library http://libvirt.org

    [unhandled content-type:application/pgp-signature]
    \
     
     \ /
      Last update: 2012-08-13 22:42    [W:2.620 / U:0.232 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site