Virtio 1.0 doesn't include a modern balloon device.
At some point we'll likely define an incompatible interface with a different
ID.  But for now, it's not a big change to support a transitional balloon
device: this has the advantage of supporting existing drivers, transparently.

The only issue is with the stats buffer, which has misaligned fields.
Seems easy to fix by prepending a 6 byte reserved field.

I'll post spec patch and qemu patches shortly.

Michael S. Tsirkin (6):
  virtio_balloon: transitional interface
  virtio: balloon might not be a legacy device
  virtio_ccw: support non-legacy balloon devices
  virtio_mmio: support non-legacy balloon devices
  virtio_pci: support non-legacy balloon devices
  virtio: drop virtio_device_is_legacy_only

 include/linux/virtio.h              |  2 --
 include/uapi/linux/virtio_balloon.h |  6 ++++++
 drivers/s390/kvm/virtio_ccw.c       | 10 +++-------
 drivers/virtio/virtio.c             |  6 ------
 drivers/virtio/virtio_balloon.c     |  8 ++++++--
 drivers/virtio/virtio_mmio.c        |  8 --------
 drivers/virtio/virtio_pci_modern.c  |  3 ---
 7 files changed, 15 insertions(+), 28 deletions(-)

-- 
MST