Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging

One of the two pending migration fix, and a small KVM patch.

# gpg: Signature made Tue 22 Jul 2014 11:49:30 BST using RSA key ID 9B4D86F2
# gpg: Can't check signature: public key not found

* remotes/bonzini/tags/for-upstream:
  kvm-all: Use 'tmpcpu' instead of 'cpu' in sub-looping to avoid 'cpu' be NULL
  exec: fix migration with devices that use address_space_rw

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