On Thu, Feb 12, 2015 at 07:12:06AM +0100, Jan Kiszka wrote: > On 2015-02-11 19:12, Kashyap Chamarthy wrote: > > Hi, > > > > This was tested with kernel-3.19.0-1.fc22) and QEMU (qemu-2.2.0-5.fc22) > > on L0 & L1. > > > > > > Description > > ----------- > > > > Inside L1, boot a nested KVM guest (L2) . Instead of a full blown > > guest, let's use `qemu-sanity-check` with KVM: > > > > $ qemu-sanity-check --accel=kvm > > > > Wwich gives you this CLI (run from a different shell), that confirms > > that the L2 guest is indeed running on KVM (and not TCG): > > > > $ ps -ef | grep -i qemu > > root 763 762 35 11:49 ttyS0 00:00:00 qemu-system-x86_64 -nographic -nodefconfig -nodefaults -machine accel=kvm -no-reboot -serial file:/tmp/tmp.rl3naPaCkZ.out -kernel /boot/vmlinuz-3.19.0-1.fc21.x86_64 -initrd /usr/lib64/qemu-sanity-check/initrd -append console=ttyS0 oops=panic panic=-1 > > > > > > Which results in: > > > > (a) L1 (guest hypervisor) completely hangs and is unresponsive. But > > when I query libvirt, (`virsh list`) the guest is still reported > > as 'running' > > > > (b) On L0, I notice a ton of these messages: > > > > skip_emulated_instruction: ip 0xffec next 0xffffffff8105e964 > > > > > > I can get `dmesg`, `dmidecode` , `x86info -a` on L0 and L1 if it helps > > in narrowing down the issue. > > > > > > Related bug and reproducer details > > ---------------------------------- > > > > > > https://bugzilla.redhat.com/show_bug.cgi?id=1191665 -- Nested KVM with > > AMD: L2 (nested guest) fails with "divide error: 0000 [#1] SMP" > > > > > > Is this a regression (of the kernel)? If so, can you bisect to the > commit that introduced it? [Sorry, I missed this reply and just noticed it.] I can't certainly say that it's a regression of Kernel. I also heard from Dan Berrange (CCed), that when an booting L2 guest it caused L1 to panic and reboot on AMD. I don't have the AMD physical machine that I tested this on, will try to find one this week and see if I can bisect. Thanks. -- /kashyap -- 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
