At 02/29/2012 06:39 PM, Avi Kivity Wrote: > On 02/29/2012 12:17 PM, Wen Congyang wrote: >>>>> >>>> Yes, crash can be so severe that it is not even detected by a kernel >>>> itself, so not OOPS message even printed. But in most cases if kernel is >>>> functional enough to print OOPS it is functional enough to call single >>>> hypercall instruction. >>> >>> Why not print the oops to virtio-serial? Or even just a regular serial >>> port? That's what bare metal does. >> >> If virtio-serial's driver has bug or the guest doesn't have such device... > > We have the same issue with the hypercall; and virtio-serial is > available on many deployed versions. How to know whether a guest has virtio-serial? Thanks Wen Congyang > >>> >>>>>> Having special kdump >>>>>> kernel that transfers dump to a host via virtio-serial channel though >>>>>> sounds interesting. May be that's what you mean. >>>>> >>>>> Yes. The "panic, starting dump" signal should be initiated by the >>>>> panicking kernel though, in case the dump fails. >>>>> >>>> Then panic hypercall sounds like a reasonable solution. >>> >>> It is, but I'm trying to see if we can get away with doing nothing. >>> >> >> If we have a reliable way with doing nothing, it is better. But I donot >> find such way. > > We won't have a 100% reliable way. But I think a variant of the driver > that doesn't use interrupts, or just using the ordinary serial driver, > should be reliable enough. > -- 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
