[xdp-hints] Re: [PATCH bpf-next v7 05/18] ice: Support HW timestamp hint

[Maciej Fijalkowski <maciej.fijalkowski@intel.com>]

On Wed, Nov 15, 2023 at 06:52:47PM +0100, Larysa Zaremba wrote:
> Use previously refactored code and create a function
> that allows XDP code to read HW timestamp.
> 
> Also, introduce packet context, where hints-related data will be stored.
> ice_xdp_buff contains only a pointer to this structure, to avoid copying it
> in ZC mode later in the series.
> 
> HW timestamp is the first supported hint in the driver,
> so also add xdp_metadata_ops.
> 
> Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>

Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>

> ---
>  drivers/net/ethernet/intel/ice/ice.h          |  2 ++
>  drivers/net/ethernet/intel/ice/ice_base.c     |  1 +
>  drivers/net/ethernet/intel/ice/ice_main.c     |  1 +
>  drivers/net/ethernet/intel/ice/ice_ptp.c      |  6 ++---
>  drivers/net/ethernet/intel/ice/ice_ptp.h      |  4 +--
>  drivers/net/ethernet/intel/ice/ice_txrx.h     | 10 +++++++-
>  drivers/net/ethernet/intel/ice/ice_txrx_lib.c | 25 ++++++++++++++++++-
>  7 files changed, 42 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h
> index 351e0d36df44..366c82a87e56 100644
> --- a/drivers/net/ethernet/intel/ice/ice.h
> +++ b/drivers/net/ethernet/intel/ice/ice.h
> @@ -989,4 +989,6 @@ static inline void ice_clear_rdma_cap(struct ice_pf *pf)
>  	set_bit(ICE_FLAG_UNPLUG_AUX_DEV, pf->flags);
>  	clear_bit(ICE_FLAG_RDMA_ENA, pf->flags);
>  }
> +
> +extern const struct xdp_metadata_ops ice_xdp_md_ops;
>  #endif /* _ICE_H_ */
> diff --git a/drivers/net/ethernet/intel/ice/ice_base.c b/drivers/net/ethernet/intel/ice/ice_base.c
> index 7fa43827a3f0..2d83f3c029e7 100644
> --- a/drivers/net/ethernet/intel/ice/ice_base.c
> +++ b/drivers/net/ethernet/intel/ice/ice_base.c
> @@ -575,6 +575,7 @@ int ice_vsi_cfg_rxq(struct ice_rx_ring *ring)
>  
>  	xdp_init_buff(&ring->xdp, ice_rx_pg_size(ring) / 2, &ring->xdp_rxq);
>  	ring->xdp.data = NULL;
> +	ring->xdp_ext.pkt_ctx = &ring->pkt_ctx;
>  	err = ice_setup_rx_ctx(ring);
>  	if (err) {
>  		dev_err(dev, "ice_setup_rx_ctx failed for RxQ %d, err %d\n",
> diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
> index 6607fa6fe556..cfb6beadcc60 100644
> --- a/drivers/net/ethernet/intel/ice/ice_main.c
> +++ b/drivers/net/ethernet/intel/ice/ice_main.c
> @@ -3397,6 +3397,7 @@ static void ice_set_ops(struct ice_vsi *vsi)
>  
>  	netdev->netdev_ops = &ice_netdev_ops;
>  	netdev->udp_tunnel_nic_info = &pf->hw.udp_tunnel_nic;
> +	netdev->xdp_metadata_ops = &ice_xdp_md_ops;
>  	ice_set_ethtool_ops(netdev);
>  
>  	if (vsi->type != ICE_VSI_PF)
> diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.c b/drivers/net/ethernet/intel/ice/ice_ptp.c
> index a435f89b262f..667264c8dc8b 100644
> --- a/drivers/net/ethernet/intel/ice/ice_ptp.c
> +++ b/drivers/net/ethernet/intel/ice/ice_ptp.c
> @@ -2105,12 +2105,12 @@ int ice_ptp_set_ts_config(struct ice_pf *pf, struct ifreq *ifr)
>  /**
>   * ice_ptp_get_rx_hwts - Get packet Rx timestamp in ns
>   * @rx_desc: Receive descriptor
> - * @rx_ring: Ring to get the cached time
> + * @pkt_ctx: Packet context to get the cached time
>   *
>   * The driver receives a notification in the receive descriptor with timestamp.
>   */
>  u64 ice_ptp_get_rx_hwts(const union ice_32b_rx_flex_desc *rx_desc,
> -			struct ice_rx_ring *rx_ring)
> +			const struct ice_pkt_ctx *pkt_ctx)
>  {
>  	u64 ts_ns, cached_time;
>  	u32 ts_high;
> @@ -2118,7 +2118,7 @@ u64 ice_ptp_get_rx_hwts(const union ice_32b_rx_flex_desc *rx_desc,
>  	if (!(rx_desc->wb.time_stamp_low & ICE_PTP_TS_VALID))
>  		return 0;
>  
> -	cached_time = READ_ONCE(rx_ring->cached_phctime);
> +	cached_time = READ_ONCE(pkt_ctx->cached_phctime);
>  
>  	/* Do not report a timestamp if we don't have a cached PHC time */
>  	if (!cached_time)
> diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.h b/drivers/net/ethernet/intel/ice/ice_ptp.h
> index 0274da964fe3..30b382ed204d 100644
> --- a/drivers/net/ethernet/intel/ice/ice_ptp.h
> +++ b/drivers/net/ethernet/intel/ice/ice_ptp.h
> @@ -299,7 +299,7 @@ s8 ice_ptp_request_ts(struct ice_ptp_tx *tx, struct sk_buff *skb);
>  enum ice_tx_tstamp_work ice_ptp_process_ts(struct ice_pf *pf);
>  
>  u64 ice_ptp_get_rx_hwts(const union ice_32b_rx_flex_desc *rx_desc,
> -			struct ice_rx_ring *rx_ring);
> +			const struct ice_pkt_ctx *pkt_ctx);
>  void ice_ptp_reset(struct ice_pf *pf);
>  void ice_ptp_prepare_for_reset(struct ice_pf *pf);
>  void ice_ptp_init(struct ice_pf *pf);
> @@ -332,7 +332,7 @@ static inline bool ice_ptp_process_ts(struct ice_pf *pf)
>  
>  static inline u64
>  ice_ptp_get_rx_hwts(const union ice_32b_rx_flex_desc *rx_desc,
> -		    struct ice_rx_ring *rx_ring)
> +		    const struct ice_pkt_ctx *pkt_ctx)
>  {
>  	return 0;
>  }
> diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.h b/drivers/net/ethernet/intel/ice/ice_txrx.h
> index 9efb42f99415..3d77c058c6de 100644
> --- a/drivers/net/ethernet/intel/ice/ice_txrx.h
> +++ b/drivers/net/ethernet/intel/ice/ice_txrx.h
> @@ -257,9 +257,14 @@ enum ice_rx_dtype {
>  	ICE_RX_DTYPE_SPLIT_ALWAYS	= 2,
>  };
>  
> +struct ice_pkt_ctx {
> +	u64 cached_phctime;
> +};
> +
>  struct ice_xdp_buff {
>  	struct xdp_buff xdp_buff;
>  	const union ice_32b_rx_flex_desc *eop_desc;
> +	const struct ice_pkt_ctx *pkt_ctx;
>  };
>  
>  /* Required for compatibility with xdp_buffs from xsk_pool */
> @@ -328,6 +333,10 @@ struct ice_rx_ring {
>  		struct xdp_buff xdp;
>  	};
>  	/* CL3 - 3rd cacheline starts here */
> +	union {
> +		struct ice_pkt_ctx pkt_ctx;
> +		u64 cached_phctime;
> +	};
>  	struct bpf_prog *xdp_prog;
>  	u16 rx_offset;
>  
> @@ -346,7 +355,6 @@ struct ice_rx_ring {
>  	struct ice_rx_ring *next;	/* pointer to next ring in q_vector */
>  	struct xsk_buff_pool *xsk_pool;
>  	dma_addr_t dma;			/* physical address of ring */
> -	u64 cached_phctime;
>  	u16 rx_buf_len;
>  	u8 dcb_tc;			/* Traffic class of ring */
>  	u8 ptp_rx;
> diff --git a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
> index 1fc1794b8e80..d57019b85641 100644
> --- a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
> +++ b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
> @@ -197,7 +197,7 @@ ice_ptp_rx_hwts_to_skb(struct ice_rx_ring *rx_ring,
>  		       const union ice_32b_rx_flex_desc *rx_desc,
>  		       struct sk_buff *skb)
>  {
> -	u64 ts_ns = ice_ptp_get_rx_hwts(rx_desc, rx_ring);
> +	u64 ts_ns = ice_ptp_get_rx_hwts(rx_desc, &rx_ring->pkt_ctx);
>  
>  	*skb_hwtstamps(skb) = (struct skb_shared_hwtstamps){
>  		.hwtstamp	= ns_to_ktime(ts_ns),
> @@ -509,3 +509,26 @@ void ice_finalize_xdp_rx(struct ice_tx_ring *xdp_ring, unsigned int xdp_res,
>  			spin_unlock(&xdp_ring->tx_lock);
>  	}
>  }
> +
> +/**
> + * ice_xdp_rx_hw_ts - HW timestamp XDP hint handler
> + * @ctx: XDP buff pointer
> + * @ts_ns: destination address
> + *
> + * Copy HW timestamp (if available) to the destination address.
> + */
> +static int ice_xdp_rx_hw_ts(const struct xdp_md *ctx, u64 *ts_ns)
> +{
> +	const struct ice_xdp_buff *xdp_ext = (void *)ctx;
> +
> +	*ts_ns = ice_ptp_get_rx_hwts(xdp_ext->eop_desc,
> +				     xdp_ext->pkt_ctx);
> +	if (!*ts_ns)
> +		return -ENODATA;
> +
> +	return 0;
> +}
> +
> +const struct xdp_metadata_ops ice_xdp_md_ops = {
> +	.xmo_rx_timestamp		= ice_xdp_rx_hw_ts,
> +};
> -- 
> 2.41.0
>