[xdp-hints] Re: [PATCH bpf-next v7 10/18] ice: Implement VLAN tag hint

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

On Wed, Nov 15, 2023 at 06:52:52PM +0100, Larysa Zaremba wrote:
> Implement .xmo_rx_vlan_tag callback to allow XDP code to read
> packet's VLAN tag.
> 
> At the same time, use vlan_tci instead of vlan_tag in touched code,
> because VLAN tag often refers to VLAN proto and VLAN TCI combined,
> while in the code we clearly store only VLAN TCI.
> 
> Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>

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

> ---
>  drivers/net/ethernet/intel/ice/ice_main.c     | 20 ++++++++++++++
>  drivers/net/ethernet/intel/ice/ice_txrx.c     |  6 ++---
>  drivers/net/ethernet/intel/ice/ice_txrx.h     |  6 ++++-
>  drivers/net/ethernet/intel/ice/ice_txrx_lib.c | 26 +++++++++++++++++++
>  drivers/net/ethernet/intel/ice/ice_txrx_lib.h |  4 +--
>  drivers/net/ethernet/intel/ice/ice_xsk.c      |  6 ++---
>  6 files changed, 59 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
> index cfb6beadcc60..485c561c129c 100644
> --- a/drivers/net/ethernet/intel/ice/ice_main.c
> +++ b/drivers/net/ethernet/intel/ice/ice_main.c
> @@ -6041,6 +6041,23 @@ ice_fix_features(struct net_device *netdev, netdev_features_t features)
>  	return features;
>  }
>  
> +/**
> + * ice_set_rx_rings_vlan_proto - update rings with new stripped VLAN proto
> + * @vsi: PF's VSI
> + * @vlan_ethertype: VLAN ethertype (802.1Q or 802.1ad) in network byte order
> + *
> + * Store current stripped VLAN proto in ring packet context,
> + * so it can be accessed more efficiently by packet processing code.
> + */
> +static void
> +ice_set_rx_rings_vlan_proto(struct ice_vsi *vsi, __be16 vlan_ethertype)
> +{
> +	u16 i;
> +
> +	ice_for_each_alloc_rxq(vsi, i)
> +		vsi->rx_rings[i]->pkt_ctx.vlan_proto = vlan_ethertype;
> +}
> +
>  /**
>   * ice_set_vlan_offload_features - set VLAN offload features for the PF VSI
>   * @vsi: PF's VSI
> @@ -6083,6 +6100,9 @@ ice_set_vlan_offload_features(struct ice_vsi *vsi, netdev_features_t features)
>  	if (strip_err || insert_err)
>  		return -EIO;
>  
> +	ice_set_rx_rings_vlan_proto(vsi, enable_stripping ?
> +				    htons(vlan_ethertype) : 0);
> +
>  	return 0;
>  }
>  
> diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.c b/drivers/net/ethernet/intel/ice/ice_txrx.c
> index 4e6546d9cf85..4fd7614f243d 100644
> --- a/drivers/net/ethernet/intel/ice/ice_txrx.c
> +++ b/drivers/net/ethernet/intel/ice/ice_txrx.c
> @@ -1183,7 +1183,7 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
>  		struct sk_buff *skb;
>  		unsigned int size;
>  		u16 stat_err_bits;
> -		u16 vlan_tag = 0;
> +		u16 vlan_tci;
>  
>  		/* get the Rx desc from Rx ring based on 'next_to_clean' */
>  		rx_desc = ICE_RX_DESC(rx_ring, ntc);
> @@ -1278,7 +1278,7 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
>  			continue;
>  		}
>  
> -		vlan_tag = ice_get_vlan_tag_from_rx_desc(rx_desc);
> +		vlan_tci = ice_get_vlan_tci(rx_desc);
>  
>  		/* pad the skb if needed, to make a valid ethernet frame */
>  		if (eth_skb_pad(skb))
> @@ -1292,7 +1292,7 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
>  
>  		ice_trace(clean_rx_irq_indicate, rx_ring, rx_desc, skb);
>  		/* send completed skb up the stack */
> -		ice_receive_skb(rx_ring, skb, vlan_tag);
> +		ice_receive_skb(rx_ring, skb, vlan_tci);
>  
>  		/* update budget accounting */
>  		total_rx_pkts++;
> diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.h b/drivers/net/ethernet/intel/ice/ice_txrx.h
> index 3d77c058c6de..886ac8450e78 100644
> --- a/drivers/net/ethernet/intel/ice/ice_txrx.h
> +++ b/drivers/net/ethernet/intel/ice/ice_txrx.h
> @@ -259,6 +259,7 @@ enum ice_rx_dtype {
>  
>  struct ice_pkt_ctx {
>  	u64 cached_phctime;
> +	__be16 vlan_proto;
>  };
>  
>  struct ice_xdp_buff {
> @@ -335,7 +336,10 @@ struct ice_rx_ring {
>  	/* CL3 - 3rd cacheline starts here */
>  	union {
>  		struct ice_pkt_ctx pkt_ctx;
> -		u64 cached_phctime;
> +		struct {
> +			u64 cached_phctime;
> +			__be16 vlan_proto;
> +		};
>  	};
>  	struct bpf_prog *xdp_prog;
>  	u16 rx_offset;
> diff --git a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
> index 26a2c218e96d..63bf9f882363 100644
> --- a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
> +++ b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
> @@ -601,7 +601,33 @@ static int ice_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
>  	return 0;
>  }
>  
> +/**
> + * ice_xdp_rx_vlan_tag - VLAN tag XDP hint handler
> + * @ctx: XDP buff pointer
> + * @vlan_proto: destination address for VLAN protocol
> + * @vlan_tci: destination address for VLAN TCI
> + *
> + * Copy VLAN tag (if was stripped) and corresponding protocol
> + * to the destination address.
> + */
> +static int ice_xdp_rx_vlan_tag(const struct xdp_md *ctx, __be16 *vlan_proto,
> +			       u16 *vlan_tci)
> +{
> +	const struct ice_xdp_buff *xdp_ext = (void *)ctx;
> +
> +	*vlan_proto = xdp_ext->pkt_ctx->vlan_proto;
> +	if (!*vlan_proto)
> +		return -ENODATA;
> +
> +	*vlan_tci = ice_get_vlan_tci(xdp_ext->eop_desc);
> +	if (!*vlan_tci)
> +		return -ENODATA;
> +
> +	return 0;
> +}
> +
>  const struct xdp_metadata_ops ice_xdp_md_ops = {
>  	.xmo_rx_timestamp		= ice_xdp_rx_hw_ts,
>  	.xmo_rx_hash			= ice_xdp_rx_hash,
> +	.xmo_rx_vlan_tag		= ice_xdp_rx_vlan_tag,
>  };
> diff --git a/drivers/net/ethernet/intel/ice/ice_txrx_lib.h b/drivers/net/ethernet/intel/ice/ice_txrx_lib.h
> index 81b8856d8e13..3893af1c11f3 100644
> --- a/drivers/net/ethernet/intel/ice/ice_txrx_lib.h
> +++ b/drivers/net/ethernet/intel/ice/ice_txrx_lib.h
> @@ -84,7 +84,7 @@ ice_build_ctob(u64 td_cmd, u64 td_offset, unsigned int size, u64 td_tag)
>  }
>  
>  /**
> - * ice_get_vlan_tag_from_rx_desc - get VLAN from Rx flex descriptor
> + * ice_get_vlan_tci - get VLAN TCI from Rx flex descriptor
>   * @rx_desc: Rx 32b flex descriptor with RXDID=2
>   *
>   * The OS and current PF implementation only support stripping a single VLAN tag
> @@ -92,7 +92,7 @@ ice_build_ctob(u64 td_cmd, u64 td_offset, unsigned int size, u64 td_tag)
>   * one is found return the tag, else return 0 to mean no VLAN tag was found.
>   */
>  static inline u16
> -ice_get_vlan_tag_from_rx_desc(union ice_32b_rx_flex_desc *rx_desc)
> +ice_get_vlan_tci(const union ice_32b_rx_flex_desc *rx_desc)
>  {
>  	u16 stat_err_bits;
>  
> diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c
> index a690e34ea8ae..aeaf6692696e 100644
> --- a/drivers/net/ethernet/intel/ice/ice_xsk.c
> +++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
> @@ -868,7 +868,7 @@ int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring, int budget)
>  		struct xdp_buff *xdp;
>  		struct sk_buff *skb;
>  		u16 stat_err_bits;
> -		u16 vlan_tag = 0;
> +		u16 vlan_tci;
>  
>  		rx_desc = ICE_RX_DESC(rx_ring, ntc);
>  
> @@ -946,10 +946,10 @@ int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring, int budget)
>  		total_rx_bytes += skb->len;
>  		total_rx_packets++;
>  
> -		vlan_tag = ice_get_vlan_tag_from_rx_desc(rx_desc);
> +		vlan_tci = ice_get_vlan_tci(rx_desc);
>  
>  		ice_process_skb_fields(rx_ring, rx_desc, skb);
> -		ice_receive_skb(rx_ring, skb, vlan_tag);
> +		ice_receive_skb(rx_ring, skb, vlan_tci);
>  	}
>  
>  	rx_ring->next_to_clean = ntc;
> -- 
> 2.41.0
>