Comment 5 for bug 1494350

Sorry but I think I've pasted my answer to the wrong bugreport. Sorry about that! I'm not using live migration.
https://lists.debian.org/debian-kernel/2014/11/msg00093.html

but seems something Debian related.

Following scenario:

Host Ubuntu 14.04
Guest Debian Jessie

Debian with 3.16.0-4-amd64 kernel has high cpu load on one of our webserver:

output from top

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
  18 root 20 0 S 11,0 50:10.35 ksoftirqd/2
   28 root 20 0 S 11,0 49:45.90 ksoftirqd/4
   13 root 20 0 S 10,1 51:25.18 ksoftirqd/1
   23 root 20 0 S 10,1 55:42.26 ksoftirqd/3
   33 root 20 0 S 8,3 43:12.53 ksoftirqd/5
    3 root 20 0 S 7,4 43:19.93 ksoftirqd/0

With backports kernel 4.2.0-0.bpo.1-amd64 or 4.2.3 from kernel.org the cpu usage is back normal.

I ran into this problem on multiple debian jessie kvm guest's. I think this is nothing qemu related. Sorry.