http://lwn.net/Articles/513317/
http://www.linux-kvm.org/page/Perf_events

perf应用程序位于内核源代码目录tools/perf下，直接编译

./perf stat -e 'kvm:*' -a sleep 1h

./perf kvm stat record -p `pgrep qemu`

See the vmexit events:
# ./perf kvm stat report --event=vmexit

See the mmio events:
# ./perf kvm stat report --event=mmio

See the ioport event:
# ./perf kvm stat report --event=ioport