Comment 4 for bug 1307473

However, you mention that you have your VM pinned to CPU 1, while the command line is doing '-cpu 4'. When I run a VM with -cpu 4 locked to a single physical cpu, it definately does not do well. I'm not sure whether to call that a bug or mis-use.

Example:

cgm create cpuset qemu
cgm setvalue cpuset qemu cpuset.cpus 0
cgm movepid cpuset qemu $$
kvm -hda x.img -cdrom ubuntu-13.10-desktop-amd64.iso -m 1024 -realtime mlock=off -smp 4,sockets=1,cores=4,threads=1 -rtc base=localtime

(resulting VM hangs; without the -smp 4,sockets=1,cores=4,threads=1' it runs fine.)