[Qemu-devel] [PATCHv4 0/2] qemu: properties for feature compatibility

[Michael S. Tsirkin]

Here's what I came up with for solving the problem of differences in
features depending on backend. This is especially important for vhost,
but it also solves the problem of difference in features in virtio
between 0.12 and 0.11.  This also enables migration between different
backends, e.g.  between host where tap supports virtio net header and
where it does not: management just needs to set features appropriately.


Changes since v3:
- fix s390 as well.

Changes since v2:
- we already have a flag to control write cache feature,
  let's not add another one

Changes since v1:
- add symbolic names for properties
- only optional features can be changed



Michael S. Tsirkin (2):
  qdev: add bit property type
  virtio: add features as qdev properties

 hw/qdev-properties.c |   70 +++++++++++++++++++++++++++++++++++++++++++++-----
 hw/qdev.h            |    9 ++++++
 hw/s390-virtio-bus.c |   12 ++++++--
 hw/s390-virtio-bus.h |    1 +
 hw/syborg_virtio.c   |   12 +++++---
 hw/virtio-balloon.c  |    4 +-
 hw/virtio-blk.c      |    6 +---
 hw/virtio-blk.h      |    8 +++++
 hw/virtio-console.c  |    4 +-
 hw/virtio-net.c      |   39 +++++++++++----------------
 hw/virtio-net.h      |   20 ++++++++++++++
 hw/virtio-pci.c      |   25 ++++++++++++-----
 hw/virtio.c          |    2 +-
 hw/virtio.h          |    7 ++++-
 14 files changed, 162 insertions(+), 57 deletions(-)