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

virtio: features, cleanups

virtio net failover
rcu cleanup

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
# gpg: Signature made Tue 29 Oct 2019 22:58:14 GMT
# gpg:                using RSA key 281F0DB8D28D5469
# gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>" [full]
# gpg:                 aka "Michael S. Tsirkin <mst@redhat.com>" [full]
# Primary key fingerprint: 0270 606B 6F3C DF3D 0B17  0970 C350 3912 AFBE 8E67
#      Subkey fingerprint: 5D09 FD08 71C8 F85B 94CA  8A0D 281F 0DB8 D28D 5469

* remotes/mst/tags/for_upstream:
  virtio: Use auto rcu_read macros
  virtio_net: use RCU_READ_LOCK_GUARD
  virtio/vhost: Use auto_rcu_read macros
  vfio: unplug failover primary device before migration
  net/virtio: add failover support
  libqos: tolerate wait-unplug migration state
  migration: add new migration state wait-unplug
  migration: allow unplug during migration for failover devices
  qapi: add failover negotiated event
  qapi: add unplug primary event
  pci: mark device having guest unplug request pending
  pci: mark devices partially unplugged
  pci: add option for net failover
  qdev/qbus: add hidden device support

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