From: Alexander Lobakin Date: Thu, 12 Jun 2025 16:02:29 +0000 (+0200) Subject: libeth: xdp: add RSS hash hint and XDP features setup helpers X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=576cc5c13d9ba53a1a24d9b34af2f939a87b7ce8;p=thirdparty%2Flinux.git libeth: xdp: add RSS hash hint and XDP features setup helpers End the XDP section by adding helpers to setup XDP features, flipping .ndo_xdp_xmit() support at runtime (in case when it's not always on), and calculating the queue clean/refill threshold. Signed-off-by: Alexander Lobakin Signed-off-by: Tony Nguyen --- diff --git a/drivers/net/ethernet/intel/libeth/xdp.c b/drivers/net/ethernet/intel/libeth/xdp.c index 1607579d65bb7..4eb0f3c6cdab6 100644 --- a/drivers/net/ethernet/intel/libeth/xdp.c +++ b/drivers/net/ethernet/intel/libeth/xdp.c @@ -340,6 +340,75 @@ head: } EXPORT_SYMBOL_GPL(libeth_xdp_return_buff_bulk); +/* Misc */ + +/** + * libeth_xdp_queue_threshold - calculate XDP queue clean/refill threshold + * @count: number of descriptors in the queue + * + * The threshold is the limit at which RQs start to refill (when the number of + * empty buffers exceeds it) and SQs get cleaned up (when the number of free + * descriptors goes below it). To speed up hotpath processing, threshold is + * always pow-2, closest to 1/4 of the queue length. + * Don't call it on hotpath, calculate and cache the threshold during the + * queue initialization. + * + * Return: the calculated threshold. + */ +u32 libeth_xdp_queue_threshold(u32 count) +{ + u32 quarter, low, high; + + if (likely(is_power_of_2(count))) + return count >> 2; + + quarter = DIV_ROUND_CLOSEST(count, 4); + low = rounddown_pow_of_two(quarter); + high = roundup_pow_of_two(quarter); + + return high - quarter <= quarter - low ? high : low; +} +EXPORT_SYMBOL_GPL(libeth_xdp_queue_threshold); + +/** + * __libeth_xdp_set_features - set XDP features for netdev + * @dev: &net_device to configure + * @xmo: XDP metadata ops (Rx hints) + * + * Set all the features libeth_xdp supports. Only the first argument is + * necessary. + * Use the non-underscored versions in drivers instead. + */ +void __libeth_xdp_set_features(struct net_device *dev, + const struct xdp_metadata_ops *xmo) +{ + xdp_set_features_flag(dev, + NETDEV_XDP_ACT_BASIC | + NETDEV_XDP_ACT_REDIRECT | + NETDEV_XDP_ACT_NDO_XMIT | + NETDEV_XDP_ACT_RX_SG | + NETDEV_XDP_ACT_NDO_XMIT_SG); + dev->xdp_metadata_ops = xmo; +} +EXPORT_SYMBOL_GPL(__libeth_xdp_set_features); + +/** + * libeth_xdp_set_redirect - toggle the XDP redirect feature + * @dev: &net_device to configure + * @enable: whether XDP is enabled + * + * Use this when XDPSQs are not always available to dynamically enable + * and disable redirect feature. + */ +void libeth_xdp_set_redirect(struct net_device *dev, bool enable) +{ + if (enable) + xdp_features_set_redirect_target(dev, true); + else + xdp_features_clear_redirect_target(dev); +} +EXPORT_SYMBOL_GPL(libeth_xdp_set_redirect); + /* Module */ static const struct libeth_xdp_ops xdp_ops __initconst = { diff --git a/include/net/libeth/xdp.h b/include/net/libeth/xdp.h index 46a2ec3c30375..c36b2ca0d04c3 100644 --- a/include/net/libeth/xdp.h +++ b/include/net/libeth/xdp.h @@ -1631,6 +1631,51 @@ void name(struct libeth_xdp_tx_bulk *bq) \ #define LIBETH_XDP_DEFINE_END() __diag_pop() +/* XMO */ + +/** + * libeth_xdp_buff_to_rq - get RQ pointer from an XDP buffer pointer + * @xdp: &libeth_xdp_buff corresponding to the queue + * @type: typeof() of the driver Rx queue structure + * @member: name of &xdp_rxq_info inside @type + * + * Often times, pointer to the RQ is needed when reading/filling metadata from + * HW descriptors. The helper can be used to quickly jump from an XDP buffer + * to the queue corresponding to its &xdp_rxq_info without introducing + * additional fields (&libeth_xdp_buff is precisely 1 cacheline long on x64). + */ +#define libeth_xdp_buff_to_rq(xdp, type, member) \ + container_of_const((xdp)->base.rxq, type, member) + +/** + * libeth_xdpmo_rx_hash - convert &libeth_rx_pt to an XDP RSS hash metadata + * @hash: pointer to the variable to write the hash to + * @rss_type: pointer to the variable to write the hash type to + * @val: hash value from the HW descriptor + * @pt: libeth parsed packet type + * + * Handle zeroed/non-available hash and convert libeth parsed packet type to + * the corresponding XDP RSS hash type. To be called at the end of + * xdp_metadata_ops idpf_xdpmo::xmo_rx_hash() implementation. + * Note that if the driver doesn't use a constant packet type lookup table but + * generates it at runtime, it must call libeth_rx_pt_gen_hash_type(pt) to + * generate XDP RSS hash type for each packet type. + * + * Return: 0 on success, -ENODATA when the hash is not available. + */ +static inline int libeth_xdpmo_rx_hash(u32 *hash, + enum xdp_rss_hash_type *rss_type, + u32 val, struct libeth_rx_pt pt) +{ + if (unlikely(!val)) + return -ENODATA; + + *hash = val; + *rss_type = pt.hash_type; + + return 0; +} + /* Tx buffer completion */ void libeth_xdp_return_buff_bulk(const struct skb_shared_info *sinfo, @@ -1697,4 +1742,49 @@ static inline void libeth_xdp_complete_tx(struct libeth_sqe *sqe, __libeth_xdp_complete_tx(sqe, cp, libeth_xdp_return_buff_bulk); } +/* Misc */ + +u32 libeth_xdp_queue_threshold(u32 count); + +void __libeth_xdp_set_features(struct net_device *dev, + const struct xdp_metadata_ops *xmo); +void libeth_xdp_set_redirect(struct net_device *dev, bool enable); + +/** + * libeth_xdp_set_features - set XDP features for netdev + * @dev: &net_device to configure + * @...: optional params, see __libeth_xdp_set_features() + * + * Set all the features libeth_xdp supports, including .ndo_xdp_xmit(). That + * said, it should be used only when XDPSQs are always available regardless + * of whether an XDP prog is attached to @dev. + */ +#define libeth_xdp_set_features(dev, ...) \ + CONCATENATE(__libeth_xdp_feat, \ + COUNT_ARGS(__VA_ARGS__))(dev, ##__VA_ARGS__) + +#define __libeth_xdp_feat0(dev) \ + __libeth_xdp_set_features(dev, NULL) +#define __libeth_xdp_feat1(dev, xmo) \ + __libeth_xdp_set_features(dev, xmo) + +/** + * libeth_xdp_set_features_noredir - enable all libeth_xdp features w/o redir + * @dev: target &net_device + * @...: optional params, see __libeth_xdp_set_features() + * + * Enable everything except the .ndo_xdp_xmit() feature, use when XDPSQs are + * not available right after netdev registration. + */ +#define libeth_xdp_set_features_noredir(dev, ...) \ + __libeth_xdp_set_features_noredir(dev, __UNIQUE_ID(dev_), \ + ##__VA_ARGS__) + +#define __libeth_xdp_set_features_noredir(dev, ud, ...) do { \ + struct net_device *ud = (dev); \ + \ + libeth_xdp_set_features(ud, ##__VA_ARGS__); \ + libeth_xdp_set_redirect(ud, false); \ +} while (0) + #endif /* __LIBETH_XDP_H */