Re: [RFC PATCH V2 0/6] mdev based hardware virtio offloading support

[Jason Wang]

On 2019/9/20 äå4:20, Jason Wang wrote:
> Hi all:
>
> There are hardware that can do virtio datapath offloading while having
> its own control path. This path tries to implement a mdev based
> unified API to support using kernel virtio driver to drive those
> devices. This is done by introducing a new mdev transport for virtio
> (virtio_mdev) and register itself as a new kind of mdev driver. Then
> it provides a unified way for kernel virtio driver to talk with mdev
> device implementation.
>
> Though the series only contain kernel driver support, the goal is to
> make the transport generic enough to support userspace drivers. This
> means vhost-mdev[1] could be built on top as well by resuing the
> transport.
>
> A sample driver is also implemented which simulate a virito-net
> loopback ethernet device on top of vringh + workqueue. This could be
> used as a reference implementation for real hardware driver.
>
> Consider mdev framework only support VFIO device and driver right now,
> this series also extend it to support other types. This is done
> through introducing class id to the device and pairing it with
> id_talbe claimed by the driver. On top, this seris also decouple
> device specific parents ops out of the common ones.
>
> Pktgen test was done with virito-net + mvnet loop back device.
>
> Please review.


CC Parav.

Thanks


> Changes from V1:
>
> - rename device id to class id
> - add docs for class id and device specific ops (device_ops)
> - split device_ops into seperate headers
> - drop the mdev_set_dma_ops()
> - use device_ops to implement the transport API, then it's not a part
>    of UAPI any more
> - use GFP_ATOMIC in mvnet sample device and other tweaks
> - set_vring_base/get_vring_base support for mvnet device
>
> Jason Wang (6):
>    mdev: class id support
>    mdev: introduce device specific ops
>    mdev: introduce virtio device and its device ops
>    virtio: introudce a mdev based transport
>    vringh: fix copy direction of vringh_iov_push_kern()
>    docs: Sample driver to demonstrate how to implement virtio-mdev
>      framework
>
>   .../driver-api/vfio-mediated-device.rst       |  11 +-
>   drivers/gpu/drm/i915/gvt/kvmgt.c              |  17 +-
>   drivers/s390/cio/vfio_ccw_ops.c               |  17 +-
>   drivers/s390/crypto/vfio_ap_ops.c             |  14 +-
>   drivers/vfio/mdev/Kconfig                     |   7 +
>   drivers/vfio/mdev/Makefile                    |   1 +
>   drivers/vfio/mdev/mdev_core.c                 |  21 +-
>   drivers/vfio/mdev/mdev_driver.c               |  14 +
>   drivers/vfio/mdev/mdev_private.h              |   1 +
>   drivers/vfio/mdev/vfio_mdev.c                 |  37 +-
>   drivers/vfio/mdev/virtio_mdev.c               | 418 +++++++++++
>   drivers/vhost/vringh.c                        |   8 +-
>   include/linux/mdev.h                          |  46 +-
>   include/linux/mod_devicetable.h               |   8 +
>   include/linux/vfio_mdev.h                     |  50 ++
>   include/linux/virtio_mdev.h                   | 141 ++++
>   samples/Kconfig                               |   7 +
>   samples/vfio-mdev/Makefile                    |   1 +
>   samples/vfio-mdev/mbochs.c                    |  19 +-
>   samples/vfio-mdev/mdpy.c                      |  19 +-
>   samples/vfio-mdev/mtty.c                      |  17 +-
>   samples/vfio-mdev/mvnet.c                     | 688 ++++++++++++++++++
>   22 files changed, 1473 insertions(+), 89 deletions(-)
>   create mode 100644 drivers/vfio/mdev/virtio_mdev.c
>   create mode 100644 include/linux/vfio_mdev.h
>   create mode 100644 include/linux/virtio_mdev.h
>   create mode 100644 samples/vfio-mdev/mvnet.c