Chris Lalancette wrote: > All, > I've been doing some migration testing of KVM guests, and have been > running > into some problems. Let me describe the setup and what I've tried, and maybe > somebody has some ideas about what might be going on here. > > Setup: > 2 identical Intel SDV boxes, Intel(R) Core(TM)2 Duo CPU E6850 @ > 3.00GHz > Both machines are running F-8 kernel, 2.6.23.8-63.fc8 x86_64, with > updated > KVM kernel modules from git. > On one machine, I have a /kvm directory that holds my guest disk image; > this directory is exported via NFS and mounted as /kvm on the secondary > machine. > > The guest in question is also an F-8 x86_64 guest, running the same kernel as > the hosts. I start it up with the following command-line: > > qemu-system-x86_64 -hda /kvm/f8x86_64.dsk -boot c -m 385 -net > nic,vlan=0,macaddr=00:13:6e:12:34:56 -net tap,vlan=0,script=/etc/kvm-ifup > -monitor stdio > > The guest starts up just fine. On the secondary machine, I use the following > command-line: > > qemu-system-x86_64 -hda /kvm/f8x86_64.dsk -boot c -m 385 -net > nic,vlan=0,macaddr=00:13:6e:12:34:56 -net tap,vlan=0,script=/etc/kvm-ifup > -monitor stdio -incoming tcp://0:4444 > > (i.e. exactly the same, but I add the -incoming parameter). When I try to do > live migration this way, things seem like they work, and it even seems like a > few instructions get executed on the destination side. However, fairly > quickly > I'll get "Disabling IRQ #11" on the console of the guest at the destination, > and > the qemu process will just spin at 100%, with no interaction possible. IRQ > #11, > incidentally, is the IRQ associated with the emulated rtl8139 card. > > This led me to suspect the in-kernel PIC/APIC emulation, and, sure enough, if > I > pass -no-kvm-irqchip (on both the source and destination), things are better; > I > can at least migrate from the host to the destination without the "Disabling > IRQ > #11" message. However, if I put any sort of load on the guest while doing > migration, I still get a hang-up, even with -no-kvm-irqchip. > > Has anyone else seen this, or have ideas where I can start debugging it? > >
[copying Uri, who is also chasing migration bugs] - check the guest kernel without an ioapic - if that works, check the ioapic load/save paths - I'd also suspect 3ead9ca0bd2214af63ea2ebf84573576b38e004e or 71ab66c92f1ecd3f1aabed0bfa2e356fb6bbfebc -- Any sufficiently difficult bug is indistinguishable from a feature. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
