On 2012-08-14 16:55, Yan Vugenfirer wrote: > > On Aug 14, 2012, at 1:42 PM, Jan Kiszka wrote: > >> On 2012-08-14 10:56, Daniel P. Berrange wrote: >>> On Mon, Aug 13, 2012 at 03:21:32PM -0300, 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? >>> >>> No, this is not satisfactory. It depends on the guest OS being >>> configured to use the serial port for console output which we >>> cannot mandate, since it may well be required for other purposes. >> > Please don't forget Windows guests, there is no console and no "Kernel Panic" string ;) > > What I used for debugging purposes on Windows guest is to register a bugcheck callback in virtio-net driver and write 1 to VIRTIO_PCI_ISR register. What prevents writing the magic words to a second serial port in the same way via that callback? Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
