Re: [PATCH 00/33] virtio-net: support AF_XDP zero copy

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

On Thu, Feb 02, 2023 at 07:00:25PM +0800, Xuan Zhuo wrote:
> XDP socket(AF_XDP) is an excellent bypass kernel network framework. The zero
> copy feature of xsk (XDP socket) needs to be supported by the driver. The
> performance of zero copy is very good.

Great! Any numbers to share?

> mlx5 and intel ixgbe already support
> this feature, This patch set allows virtio-net to support xsk's zerocopy xmit
> feature.
> 
> Virtio-net did not support per-queue reset, so it was impossible to support XDP
> Socket Zerocopy. At present, we have completed the work of Virtio Spec and
> Kernel in Per-Queue Reset. It is time for Virtio-Net to complete the support for
> the XDP Socket Zerocopy.
> 
> Virtio-net can not increase the queue at will, so xsk shares the queue with
> kernel.
> 
> On the other hand, Virtio-Net does not support generate interrupt manually, so
> when we wakeup tx xmit, we used some tips. If the CPU run by TX NAPI last time
> is other CPUs, use IPI to wake up NAPI on the remote CPU. If it is also the
> local CPU, then we wake up sofrirqd.
> 
> Please review.
> 
> Thanks.
> 
> 
> Xuan Zhuo (33):
>   virtio_ring: virtqueue_add() support premapped
>   virtio_ring: split: virtqueue_add_split() support premapped
>   virtio_ring: packed: virtqueue_add_packed() support premapped
>   virtio_ring: introduce virtqueue_add_outbuf_premapped()
>   virtio_ring: introduce virtqueue_add_inbuf_premapped()
>   virtio_ring: introduce virtqueue_reset()
>   virtio_ring: add api virtio_dma_map() for advance dma
>   virtio_ring: introduce dma sync api for virtio
>   xsk: xsk_buff_pool add callback for dma_sync
>   xsk: support virtio DMA map
>   virtio_net: rename free_old_xmit_skbs to free_old_xmit
>   virtio_net: unify the code for recycling the xmit ptr
>   virtio_net: virtnet_poll_tx support rescheduled
>   virtio_net: independent directory
>   virtio_net: move to virtio_net.h
>   virtio_net: introduce virtnet_xdp_handler() to seprate the logic of
>     run xdp
>   virtio_net: receive_small() use virtnet_xdp_handler()
>   virtio_net: receive_merageable() use virtnet_xdp_handler()
>   virtio_net: introduce virtnet_tx_reset()
>   virtio_net: xsk: introduce virtnet_rq_bind_xsk_pool()
>   virtio_net: xsk: introduce virtnet_xsk_pool_enable()
>   virtio_net: xsk: introduce xsk disable
>   virtio_net: xsk: support xsk setup
>   virtio_net: xsk: stop disable tx napi
>   virtio_net: xsk: __free_old_xmit distinguishes xsk buffer
>   virtio_net: virtnet_sq_free_unused_buf() check xsk buffer
>   virtio_net: virtnet_rq_free_unused_buf() check xsk buffer
>   net: introduce napi_tx_raise()
>   virtio_net: xsk: tx: support tx
>   virtio_net: xsk: tx: support wakeup
>   virtio_net: xsk: tx: auto wakeup when free old xmit
>   virtio_net: xsk: rx: introduce add_recvbuf_xsk()
>   virtio_net: xsk: rx: introduce receive_xsk() to recv xsk buffer
> 
>  MAINTAINERS                                 |   2 +-
>  drivers/net/Kconfig                         |   8 +-
>  drivers/net/Makefile                        |   2 +-
>  drivers/net/virtio/Kconfig                  |  11 +
>  drivers/net/virtio/Makefile                 |   8 +
>  drivers/net/{virtio_net.c => virtio/main.c} | 564 +++++++-------------
>  drivers/net/virtio/virtio_net.h             | 317 +++++++++++
>  drivers/net/virtio/xsk.c                    | 524 ++++++++++++++++++
>  drivers/net/virtio/xsk.h                    |  33 ++
>  drivers/virtio/virtio_ring.c                | 376 +++++++++++--
>  include/linux/netdevice.h                   |   7 +
>  include/linux/virtio.h                      |  29 +
>  include/net/xsk_buff_pool.h                 |   6 +
>  net/core/dev.c                              |  11 +
>  net/xdp/xsk_buff_pool.c                     |  79 ++-
>  15 files changed, 1541 insertions(+), 436 deletions(-)
>  create mode 100644 drivers/net/virtio/Kconfig
>  create mode 100644 drivers/net/virtio/Makefile
>  rename drivers/net/{virtio_net.c => virtio/main.c} (92%)
>  create mode 100644 drivers/net/virtio/virtio_net.h
>  create mode 100644 drivers/net/virtio/xsk.c
>  create mode 100644 drivers/net/virtio/xsk.h
> 
> -- 
> 2.32.0.3.g01195cf9f