Merge remote-tracking branch 'remotes/stefanha/tags/tracing-pull-request' into staging

Merge remote-tracking branch 'remotes/stefanha/tags/tracing-pull-request' into staging

# gpg: Signature made Wed 28 Sep 2016 22:30:45 BST
# gpg:                using RSA key 0x9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha/tags/tracing-pull-request:
  trace: Document the execution mode of guest events
  trace: Add event "guest_cpu_reset"
  trace: Add event "guest_cpu_enter"
  trace: Properly initialize dynamic event states in hot-plugged vCPUs
  trace: move hw/virtio/virtio-balloon.c trace points into correct file
  trace: move hw/mem/pc-dimm.c trace points into correct file
  trace: move util/qemu-coroutine*.c trace points into correct file
  trace: move util/buffer.c trace points into correct file

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>