virtio, pc: fixes and features

more guest error handling for virtio devices
virtio migration rework
pc fixes

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

# gpg: Signature made Mon 10 Oct 2016 00:39:11 BST
# gpg:                using RSA key 0x281F0DB8D28D5469
# gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>"
# gpg:                 aka "Michael S. Tsirkin <mst@redhat.com>"
# 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: (33 commits)
  intel-iommu: Check IOAPIC's Trigger Mode against the one in IRTE
  virtio: cleanup VMSTATE_VIRTIO_DEVICE
  vhost-vsock: convert VMSTATE_VIRTIO_DEVICE
  virtio-rng: convert VMSTATE_VIRTIO_DEVICE
  virtio-balloon: convert VMSTATE_VIRTIO_DEVICE
  virtio-scsi: convert VMSTATE_VIRTIO_DEVICE
  virtio-input: convert VMSTATE_VIRTIO_DEVICE
  virtio-gpu: convert VMSTATE_VIRTIO_DEVICE
  virtio-serial: convert VMSTATE_VIRTIO_DEVICE
  virtio-9p: convert VMSTATE_VIRTIO_DEVICE
  virtio-net: convert VMSTATE_VIRTIO_DEVICE
  virtio-blk: convert VMSTATE_VIRTIO_DEVICE
  virtio: prepare change VMSTATE_VIRTIO_DEVICE macro
  net: don't poke at chardev internal QemuOpts
  virtio-scsi: handle virtio_scsi_set_config() error
  virtio-scsi: convert virtio_scsi_bad_req() to use virtio_error()
  virtio-net: handle virtio_net_flush_tx() errors
  virtio-net: handle virtio_net_receive() errors
  virtio-net: handle virtio_net_handle_ctrl() error
  virtio-blk: handle virtio_blk_handle_request() errors
  ...

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