[xdp-hints] Re: [PATCH bpf-next v2 7/8] mxl4: Support RX XDP metadata

[Stanislav Fomichev <sdf@google.com>]

On Tue, Nov 22, 2022 at 5:50 AM Tariq Toukan <ttoukan.linux@gmail.com> wrote:
>
>
>
> On 11/21/2022 8:25 PM, Stanislav Fomichev wrote:
> > RX timestamp and hash for now. Tested using the prog from the next
> > patch.
> >
> > Also enabling xdp metadata support; don't see why it's disabled,
> > there is enough headroom..
> >
> > Cc: Tariq Toukan <tariqt@nvidia.com>
> > Cc: John Fastabend <john.fastabend@gmail.com>
> > Cc: David Ahern <dsahern@gmail.com>
> > Cc: Martin KaFai Lau <martin.lau@linux.dev>
> > Cc: Jakub Kicinski <kuba@kernel.org>
> > Cc: Willem de Bruijn <willemb@google.com>
> > Cc: Jesper Dangaard Brouer <brouer@redhat.com>
> > Cc: Anatoly Burakov <anatoly.burakov@intel.com>
> > Cc: Alexander Lobakin <alexandr.lobakin@intel.com>
> > Cc: Magnus Karlsson <magnus.karlsson@gmail.com>
> > Cc: Maryam Tahhan <mtahhan@redhat.com>
> > Cc: xdp-hints@xdp-project.net
> > Cc: netdev@vger.kernel.org
> > Signed-off-by: Stanislav Fomichev <sdf@google.com>
> > ---
> >   .../net/ethernet/mellanox/mlx4/en_netdev.c    | 10 ++++
> >   drivers/net/ethernet/mellanox/mlx4/en_rx.c    | 48 ++++++++++++++++++-
> >   include/linux/mlx4/device.h                   |  7 +++
> >   3 files changed, 64 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
> > index 8800d3f1f55c..1cb63746a851 100644
> > --- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
> > +++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
> > @@ -2855,6 +2855,11 @@ static const struct net_device_ops mlx4_netdev_ops = {
> >       .ndo_features_check     = mlx4_en_features_check,
> >       .ndo_set_tx_maxrate     = mlx4_en_set_tx_maxrate,
> >       .ndo_bpf                = mlx4_xdp,
> > +
> > +     .ndo_xdp_rx_timestamp_supported = mlx4_xdp_rx_timestamp_supported,
> > +     .ndo_xdp_rx_timestamp   = mlx4_xdp_rx_timestamp,
> > +     .ndo_xdp_rx_hash_supported = mlx4_xdp_rx_hash_supported,
> > +     .ndo_xdp_rx_hash        = mlx4_xdp_rx_hash,
> >   };
> >
> >   static const struct net_device_ops mlx4_netdev_ops_master = {
> > @@ -2887,6 +2892,11 @@ static const struct net_device_ops mlx4_netdev_ops_master = {
> >       .ndo_features_check     = mlx4_en_features_check,
> >       .ndo_set_tx_maxrate     = mlx4_en_set_tx_maxrate,
> >       .ndo_bpf                = mlx4_xdp,
> > +
> > +     .ndo_xdp_rx_timestamp_supported = mlx4_xdp_rx_timestamp_supported,
> > +     .ndo_xdp_rx_timestamp   = mlx4_xdp_rx_timestamp,
> > +     .ndo_xdp_rx_hash_supported = mlx4_xdp_rx_hash_supported,
> > +     .ndo_xdp_rx_hash        = mlx4_xdp_rx_hash,
> >   };
> >
> >   struct mlx4_en_bond {
> > diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> > index 467356633172..fd14d59f6cbf 100644
> > --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> > +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> > @@ -663,8 +663,50 @@ static int check_csum(struct mlx4_cqe *cqe, struct sk_buff *skb, void *va,
> >
> >   struct mlx4_xdp_buff {
> >       struct xdp_buff xdp;
> > +     struct mlx4_cqe *cqe;
> > +     struct mlx4_en_dev *mdev;
> > +     struct mlx4_en_rx_ring *ring;
> > +     struct net_device *dev;
> >   };
> >
> > +bool mlx4_xdp_rx_timestamp_supported(const struct xdp_md *ctx)
> > +{
> > +     struct mlx4_xdp_buff *_ctx = (void *)ctx;
> > +
> > +     return _ctx->ring->hwtstamp_rx_filter == HWTSTAMP_FILTER_ALL;
> > +}
> > +
> > +u64 mlx4_xdp_rx_timestamp(const struct xdp_md *ctx)
> > +{
> > +     struct mlx4_xdp_buff *_ctx = (void *)ctx;
> > +     unsigned int seq;
> > +     u64 timestamp;
> > +     u64 nsec;
> > +
> > +     timestamp = mlx4_en_get_cqe_ts(_ctx->cqe);
> > +
> > +     do {
> > +             seq = read_seqbegin(&_ctx->mdev->clock_lock);
> > +             nsec = timecounter_cyc2time(&_ctx->mdev->clock, timestamp);
> > +     } while (read_seqretry(&_ctx->mdev->clock_lock, seq));
> > +
>
> This is open-code version of mlx4_en_fill_hwtstamps.
> Better use the existing function.

That one assumes the skb_shared_hwtstamps argument :-(
Should I try to separate the common parts into some new helper function instead?

Or maybe I can just change mlx4_en_fill_hwtstamps to the following?

u64 mlx4_en_fill_hwtstamps(struct mlx4_en_dev *mdev, u64 timestamp)
{
   ...
   return ns_to_ktime(nsec);
}

And replace existing callers with:

skb_hwtstamps(skb)->hwtstamp = mlx4_en_fill_hwtstamps(priv->mdev, timestamp).

?


> > +     return ns_to_ktime(nsec);
> > +}
> > +
> > +bool mlx4_xdp_rx_hash_supported(const struct xdp_md *ctx)
> > +{
> > +     struct mlx4_xdp_buff *_ctx = (void *)ctx;
> > +
> > +     return _ctx->dev->features & NETIF_F_RXHASH;
> > +}
> > +
> > +u32 mlx4_xdp_rx_hash(const struct xdp_md *ctx)
> > +{
> > +     struct mlx4_xdp_buff *_ctx = (void *)ctx;
> > +
> > +     return be32_to_cpu(_ctx->cqe->immed_rss_invalid);
> > +}
> > +
> >   int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int budget)
> >   {
> >       struct mlx4_en_priv *priv = netdev_priv(dev);
> > @@ -781,8 +823,12 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
> >                                               DMA_FROM_DEVICE);
> >
> >                       xdp_prepare_buff(&mxbuf.xdp, va - frags[0].page_offset,
> > -                                      frags[0].page_offset, length, false);
> > +                                      frags[0].page_offset, length, true);
> >                       orig_data = mxbuf.xdp.data;
> > +                     mxbuf.cqe = cqe;
> > +                     mxbuf.mdev = priv->mdev;
> > +                     mxbuf.ring = ring;
> > +                     mxbuf.dev = dev;
> >
> >                       act = bpf_prog_run_xdp(xdp_prog, &mxbuf.xdp);
> >
> > diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h
> > index 6646634a0b9d..d5904da1d490 100644
> > --- a/include/linux/mlx4/device.h
> > +++ b/include/linux/mlx4/device.h
> > @@ -1585,4 +1585,11 @@ static inline int mlx4_get_num_reserved_uar(struct mlx4_dev *dev)
> >       /* The first 128 UARs are used for EQ doorbells */
> >       return (128 >> (PAGE_SHIFT - dev->uar_page_shift));
> >   }
> > +
> > +struct xdp_md;
> > +bool mlx4_xdp_rx_timestamp_supported(const struct xdp_md *ctx);
> > +u64 mlx4_xdp_rx_timestamp(const struct xdp_md *ctx);
> > +bool mlx4_xdp_rx_hash_supported(const struct xdp_md *ctx);
> > +u32 mlx4_xdp_rx_hash(const struct xdp_md *ctx);
> > +
> >   #endif /* MLX4_DEVICE_H */