[Qemu-devel] [PATCHv6 0/3] qemu: properties for feature compatibility

[Qemu-devel] [PATCHv6 0/3] qemu: properties for feature compatibility

[Michael S. Tsirkin]

Here's what I came up with for solving the problem of differences 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.
Compat bits are yet to be set, will be done when this patch is applied.

Changes since v5:
- added patch to rename features->guest_features

Changes since v4:
- Save bit offset in a separate field, offset is in bytes

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

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

Acked-by: Gerd Hoffmann <kraxel@redhat.com>


Michael S. Tsirkin (3):
  qdev: add bit property type
  virtio: rename features -> guest_features
  virtio: add features as qdev properties

 hw/qdev-properties.c |   62 ++++++++++++++++++++++++++++++++++++++++++++-----
 hw/qdev.h            |   11 +++++++++
 hw/s390-virtio-bus.c |   14 ++++++++---
 hw/s390-virtio-bus.h |    1 +
 hw/syborg_virtio.c   |   16 +++++++-----
 hw/virtio-balloon.c  |    4 +-
 hw/virtio-blk.c      |    6 +----
 hw/virtio-blk.h      |    8 ++++++
 hw/virtio-console.c  |    4 +-
 hw/virtio-net.c      |   49 +++++++++++++++++----------------------
 hw/virtio-net.h      |   20 ++++++++++++++++
 hw/virtio-pci.c      |   29 +++++++++++++++--------
 hw/virtio.c          |   10 ++++----
 hw/virtio.h          |    9 +++++-
 14 files changed, 171 insertions(+), 72 deletions(-)