On Thu, Oct 12, 2023 at 07:05:13PM +0200, Larysa Zaremba wrote:
> In AF_XDP ZC, xdp_buff is not stored on ring,
> instead it is provided by xsk_buff_pool.
> Space for metadata sources right after such buffers was already reserved
> in commit 94ecc5ca4dbf ("xsk: Add cb area to struct xdp_buff_xsk").
> This makes the implementation rather straightforward.
>
> Update AF_XDP ZC packet processing to support XDP hints.
>
> Signed-off-by: Larysa Zaremba <larysa.zaremba@xxxxxxxxx>
> ---
> drivers/net/ethernet/intel/ice/ice_xsk.c | 34 ++++++++++++++++++++++--
> 1 file changed, 32 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c
> index ef778b8e6d1b..6ca620b2fbdd 100644
> --- a/drivers/net/ethernet/intel/ice/ice_xsk.c
> +++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
> @@ -752,22 +752,51 @@ static int ice_xmit_xdp_tx_zc(struct xdp_buff *xdp,
> return ICE_XDP_CONSUMED;
> }
>
> +/**
> + * ice_prepare_pkt_ctx_zc - Prepare packet context for XDP hints
> + * @xdp: xdp_buff used as input to the XDP program
> + * @eop_desc: End of packet descriptor
> + * @rx_ring: Rx ring with packet context
> + *
> + * In regular XDP, xdp_buff is placed inside the ring structure,
> + * just before the packet context, so the latter can be accessed
> + * with xdp_buff address only at all times, but in ZC mode,
s/only// ?
> + * xdp_buffs come from the pool, so we need to reinitialize
> + * context for every packet.
> + *
> + * We can safely convert xdp_buff_xsk to ice_xdp_buff,
> + * because there are XSK_PRIV_MAX bytes reserved in xdp_buff_xsk
> + * right after xdp_buff, for our private use.
> + * XSK_CHECK_PRIV_TYPE() ensures we do not go above the limit.
> + */
> +static void ice_prepare_pkt_ctx_zc(struct xdp_buff *xdp,
> + union ice_32b_rx_flex_desc *eop_desc,
> + struct ice_rx_ring *rx_ring)
> +{
> + XSK_CHECK_PRIV_TYPE(struct ice_xdp_buff);
> + ((struct ice_xdp_buff *)xdp)->pkt_ctx = rx_ring->pkt_ctx;
> + ice_xdp_meta_set_desc(xdp, eop_desc);
> +}
> +
> /**
> * ice_run_xdp_zc - Executes an XDP program in zero-copy path
> * @rx_ring: Rx ring
> * @xdp: xdp_buff used as input to the XDP program
> * @xdp_prog: XDP program to run
> * @xdp_ring: ring to be used for XDP_TX action
> + * @rx_desc: packet descriptor
> *
> * Returns any of ICE_XDP_{PASS, CONSUMED, TX, REDIR}
> */
> static int
> ice_run_xdp_zc(struct ice_rx_ring *rx_ring, struct xdp_buff *xdp,
> - struct bpf_prog *xdp_prog, struct ice_tx_ring *xdp_ring)
> + struct bpf_prog *xdp_prog, struct ice_tx_ring *xdp_ring,
> + union ice_32b_rx_flex_desc *rx_desc)
> {
> int err, result = ICE_XDP_PASS;
> u32 act;
>
> + ice_prepare_pkt_ctx_zc(xdp, rx_desc, rx_ring);
> act = bpf_prog_run_xdp(xdp_prog, xdp);
>
> if (likely(act == XDP_REDIRECT)) {
> @@ -907,7 +936,8 @@ int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring, int budget)
> if (ice_is_non_eop(rx_ring, rx_desc))
> continue;
>
> - xdp_res = ice_run_xdp_zc(rx_ring, first, xdp_prog, xdp_ring);
> + xdp_res = ice_run_xdp_zc(rx_ring, first, xdp_prog, xdp_ring,
> + rx_desc);
> if (likely(xdp_res & (ICE_XDP_TX | ICE_XDP_REDIR))) {
> xdp_xmit |= xdp_res;
> } else if (xdp_res == ICE_XDP_EXIT) {
> --
> 2.41.0
>
