Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into staging

virtio fixes for 2.4

Mostly virtio 1 spec compliance fixes.
We are unlikely to make it perfectly compliant in
the first release, but it seems worth it to try.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
# gpg: Signature made Mon Jul 27 21:55:48 2015 BST using RSA key ID D28D5469
# gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>"
# gpg:                 aka "Michael S. Tsirkin <mst@redhat.com>"

* remotes/mst/tags/for_upstream:
  virtio: minor cleanup
  acpi: fix pvpanic device is not shown in ui
  virtio-blk: only clear VIRTIO_F_ANY_LAYOUT for legacy device
  virtio-blk: fail get_features when both scsi and 1.0 were set
  virtio: get_features() can fail
  virtio-pci: fix memory MR cleanup for modern
  virtio: set any_layout in virtio core
  virtio-9p: fix any_layout
  virtio-serial: fix ANY_LAYOUT
  virtio: hide legacy features from modern guests

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