RE: [PATCH V2 0/8] mdev based hardware virtio offloading support

From: Tian, Kevin
Date: Wed Sep 25 2019 - 04:24:47 EST


> From: Jason Wang [mailto:jasowang@xxxxxxxxxx]
> Sent: Tuesday, September 24, 2019 9:53 PM
>
> 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 contains 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

id_table claimed ... this series ...

> device specific parents ops out of the common ones.
>
> Pktgen test was done with virito-net + mvnet loop back device.
>
> Please review.
>
> [1] https://lkml.org/lkml/2019/9/16/869
>
> Changes from V1:
>
> - move virtio_mdev.c to drivers/virtio
> - store class_id in mdev_device instead of mdev_parent
> - store device_ops in mdev_device instead of mdev_parent
> - reorder the patch, vringh fix comes first
> - really silent compiling warnings
> - really switch to use u16 for class_id
> - uevent and modpost support for mdev class_id
> - vraious tweaks per comments from Parav
>
> Changes from RFC-V2:
>
> - silent compile warnings on some specific configuration
> - use u16 instead u8 for class id
> - reseve MDEV_ID_VHOST for future vhost-mdev work
> - introduce "virtio" type for mvnet and make "vhost" type for future
> work
> - add entries in MAINTAINER
> - tweak and typos fixes in commit log
>
> Changes from RFC-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 (8):
> vringh: fix copy direction of vringh_iov_push_kern()
> mdev: class id support
> mdev: bus uevent support
> modpost: add support for mdev class id
> mdev: introduce device specific ops
> mdev: introduce virtio device and its device ops
> virtio: introduce a mdev based transport
> docs: sample driver to demonstrate how to implement virtio-mdev
> framework
>
> .../driver-api/vfio-mediated-device.rst | 7 +-
> MAINTAINERS | 2 +
> drivers/gpu/drm/i915/gvt/kvmgt.c | 18 +-
> drivers/s390/cio/vfio_ccw_ops.c | 18 +-
> drivers/s390/crypto/vfio_ap_ops.c | 14 +-
> drivers/vfio/mdev/mdev_core.c | 19 +
> drivers/vfio/mdev/mdev_driver.c | 22 +
> drivers/vfio/mdev/mdev_private.h | 2 +
> drivers/vfio/mdev/vfio_mdev.c | 45 +-
> drivers/vhost/vringh.c | 8 +-
> drivers/virtio/Kconfig | 7 +
> drivers/virtio/Makefile | 1 +
> drivers/virtio/virtio_mdev.c | 417 +++++++++++
> include/linux/mdev.h | 52 +-
> include/linux/mod_devicetable.h | 8 +
> include/linux/vfio_mdev.h | 52 ++
> include/linux/virtio_mdev.h | 145 ++++
> samples/Kconfig | 7 +
> samples/vfio-mdev/Makefile | 1 +
> samples/vfio-mdev/mbochs.c | 20 +-
> samples/vfio-mdev/mdpy.c | 20 +-
> samples/vfio-mdev/mtty.c | 18 +-
> samples/vfio-mdev/mvnet.c | 692 ++++++++++++++++++
> scripts/mod/devicetable-offsets.c | 3 +
> scripts/mod/file2alias.c | 10 +
> 25 files changed, 1524 insertions(+), 84 deletions(-)
> create mode 100644 drivers/virtio/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
>
> --
> 2.19.1