At 02/29/2012 06:08 PM, Avi Kivity Wrote: > On 02/29/2012 12:05 PM, Gleb Natapov wrote: >> On Wed, Feb 29, 2012 at 12:00:41PM +0200, Avi Kivity wrote: >>> On 02/29/2012 11:55 AM, Gleb Natapov wrote: >>>>>> >>>>> >>>>> How about using a virtio-serial channel for this? You can transfer any >>>>> amount of information (including the dump itself). >>>>> >>>> Isn't it unreliable after the guest panicked? >>> >>> So is calling hypercalls, or dumping, or writing to the screen. Of >>> course calling a hypercall is simpler and so is more reliable. >>> >> 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... > >>>> 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. Thanks Wen Congyang -- 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
