Re: [PATCH RFC v4 00/16] qemu: towards virtio-1 host support

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Nov 27, 2014 at 04:16:33PM +0100, Cornelia Huck wrote:
> Yet another version of the virtio-1 support patches.
> 
> This one has seen some (very) light testing with the virtio-1 guest
> support patches currently on vhost-next.
> 
> Changes from v3:
> 
> - Add support for FEATURES_OK. We refuse to set features after the
>   driver has set this in the status field, and we allow to fail
>   setting the status if the features are inconsistent.
> - Add missing virtio-1 changes for virtio-net (header size and mac).
> - Dropped setting the VERSION_1 bit for virtio-blk: There's still
>   some stuff missing.
> 
> For virtio-blk, we need to validate the feature bits if version 1 is
> negotiated: some legacy features are not allowed in that case. I'm not
> quite sure how to handle this, though. We could use the new
> validate_features callback to verify that the driver negotiated a
> sensible feature set, but that would require us to offer a superset
> of legacy and version 1 bits, which feels wrong. Any ideas?

No, that's violating the spec.
I think the simplest way is to have separate features and
legacy_features fields.  Present the correct one depending on which
revision was negotiated.


> Cornelia Huck (13):
>   virtio: cull virtio_bus_set_vdev_features
>   virtio: support more feature bits
>   s390x/virtio-ccw: fix check for WRITE_FEAT
>   virtio: introduce legacy virtio devices
>   virtio: allow virtio-1 queue layout
>   dataplane: allow virtio-1 devices
>   s390x/virtio-ccw: support virtio-1 set_vq format
>   virtio: disallow late feature changes for virtio-1
>   virtio: allow to fail setting status
>   s390x/virtio-ccw: enable virtio 1.0
>   virtio-net: no writeable mac for virtio-1
>   virtio-net: support longer header
>   virtio-net: enable virtio 1.0
> 
> Thomas Huth (3):
>   linux-headers/virtio_config: Update with VIRTIO_F_VERSION_1
>   s390x/css: Add a callback for when subchannel gets disabled
>   s390x/virtio-ccw: add virtio set-revision call
> 
>  hw/9pfs/virtio-9p-device.c                    |    7 +-
>  hw/block/dataplane/virtio-blk.c               |    4 +-
>  hw/block/virtio-blk.c                         |    9 +-
>  hw/char/virtio-serial-bus.c                   |    9 +-
>  hw/net/virtio-net.c                           |   52 +++++--
>  hw/s390x/css.c                                |   12 ++
>  hw/s390x/css.h                                |    1 +
>  hw/s390x/s390-virtio-bus.c                    |    9 +-
>  hw/s390x/virtio-ccw.c                         |  206 +++++++++++++++++++------
>  hw/s390x/virtio-ccw.h                         |    7 +-
>  hw/scsi/vhost-scsi.c                          |    7 +-
>  hw/scsi/virtio-scsi-dataplane.c               |    2 +-
>  hw/scsi/virtio-scsi.c                         |   10 +-
>  hw/virtio/Makefile.objs                       |    2 +-
>  hw/virtio/dataplane/Makefile.objs             |    2 +-
>  hw/virtio/dataplane/vring.c                   |   96 ++++++------
>  hw/virtio/virtio-balloon.c                    |    8 +-
>  hw/virtio/virtio-bus.c                        |   23 +--
>  hw/virtio/virtio-mmio.c                       |    9 +-
>  hw/virtio/virtio-pci.c                        |   13 +-
>  hw/virtio/virtio-rng.c                        |    2 +-
>  hw/virtio/virtio.c                            |   88 +++++++++--
>  include/hw/virtio/dataplane/vring-accessors.h |   75 +++++++++
>  include/hw/virtio/dataplane/vring.h           |   14 +-
>  include/hw/virtio/virtio-access.h             |    4 +
>  include/hw/virtio/virtio-bus.h                |   10 +-
>  include/hw/virtio/virtio.h                    |   39 ++++-
>  linux-headers/linux/virtio_config.h           |    3 +
>  28 files changed, 523 insertions(+), 200 deletions(-)
>  create mode 100644 include/hw/virtio/dataplane/vring-accessors.h
> 
> -- 
> 1.7.9.5