net/mlx5e: Use runtime page_shift for striding RQ

This commit allows striding RQ to determine MTT page size at runtime,
instead of sticking to the compile-time PAGE_SIZE. This functionality
will be used by a following commit that adjusts the MTT page size to the
XSK frame size.

Stick with PAGE_SIZE for XSK on legacy RQ, as frag_stride is not used in
data path, it only helps calculate how pages are partitioned into
fragments, and PAGE_SIZE will ensure each fragment starts at the
beginning of a new allocation unit (XSK frame).

Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 164 insertions, 34 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/params.c b/drivers/net/ethernet/mellanox/mlx5/core/en/params.c
index 5f8912e8404d..1a0d8f9102df 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/params.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/params.c
@@ -7,15 +7,96 @@
 #include "en_accel/en_accel.h"
 #include "en_accel/ipsec.h"
 
-u16 mlx5e_mpwrq_umr_wqe_sz(u8 pages_per_wqe)
+static u8 mlx5e_mpwrq_min_page_shift(struct mlx5_core_dev *mdev)
 {
-	return sizeof(struct mlx5e_umr_wqe) +
+	u8 min_page_shift = MLX5_CAP_GEN_2(mdev, log_min_mkey_entity_size);
+
+	return min_page_shift ? : 12;
+}
+
+u8 mlx5e_mpwrq_page_shift(struct mlx5_core_dev *mdev, struct mlx5e_xsk_param *xsk)
+{
+	u8 min_page_shift = mlx5e_mpwrq_min_page_shift(mdev);
+	u8 req_page_shift = PAGE_SHIFT;
+
+	/* Regular RQ uses order-0 pages, the NIC must be able to map them. */
+	if (WARN_ON_ONCE(!xsk && req_page_shift < min_page_shift))
+		min_page_shift = req_page_shift;
+
+	return max(req_page_shift, min_page_shift);
+}
+
+u8 mlx5e_mpwrq_log_wqe_sz(struct mlx5_core_dev *mdev, u8 page_shift)
+{
+	u8 max_pages_per_wqe, max_log_mpwqe_size;
+	u16 max_wqe_size;
+
+	/* Keep in sync with MLX5_MPWRQ_MAX_PAGES_PER_WQE. */
+	max_wqe_size = mlx5e_get_max_sq_aligned_wqebbs(mdev) * MLX5_SEND_WQE_BB;
+	max_pages_per_wqe = ALIGN_DOWN(max_wqe_size - sizeof(struct mlx5e_umr_wqe),
+				       MLX5_UMR_MTT_ALIGNMENT) / sizeof(struct mlx5_mtt);
+	max_log_mpwqe_size = ilog2(max_pages_per_wqe) + page_shift;
+
+	WARN_ON_ONCE(max_log_mpwqe_size < MLX5E_ORDER2_MAX_PACKET_MTU);
+
+	return min_t(u8, max_log_mpwqe_size, MLX5_MPWRQ_MAX_LOG_WQE_SZ);
+}
+
+u8 mlx5e_mpwrq_pages_per_wqe(struct mlx5_core_dev *mdev, u8 page_shift)
+{
+	u8 log_wqe_sz = mlx5e_mpwrq_log_wqe_sz(mdev, page_shift);
+	u8 pages_per_wqe;
+
+	pages_per_wqe = log_wqe_sz > page_shift ? (1 << (log_wqe_sz - page_shift)) : 1;
+
+	/* Sanity check for further calculations to succeed. */
+	BUILD_BUG_ON(MLX5_MPWRQ_MAX_PAGES_PER_WQE > 64);
+	if (WARN_ON_ONCE(pages_per_wqe > MLX5_MPWRQ_MAX_PAGES_PER_WQE))
+		return MLX5_MPWRQ_MAX_PAGES_PER_WQE;
+
+	return pages_per_wqe;
+}
+
+u16 mlx5e_mpwrq_umr_wqe_sz(struct mlx5_core_dev *mdev, u8 page_shift)
+{
+	u8 pages_per_wqe = mlx5e_mpwrq_pages_per_wqe(mdev, page_shift);
+	u16 umr_wqe_sz;
+
+	umr_wqe_sz = sizeof(struct mlx5e_umr_wqe) +
 		ALIGN(pages_per_wqe * sizeof(struct mlx5_mtt), MLX5_UMR_MTT_ALIGNMENT);
+
+	WARN_ON_ONCE(DIV_ROUND_UP(umr_wqe_sz, MLX5_SEND_WQE_DS) > MLX5_WQE_CTRL_DS_MASK);
+
+	return umr_wqe_sz;
+}
+
+u8 mlx5e_mpwrq_umr_wqebbs(struct mlx5_core_dev *mdev, u8 page_shift)
+{
+	return DIV_ROUND_UP(mlx5e_mpwrq_umr_wqe_sz(mdev, page_shift), MLX5_SEND_WQE_BB);
 }
 
-u8 mlx5e_mpwrq_umr_wqebbs(u8 pages_per_wqe)
+u8 mlx5e_mpwrq_mtts_per_wqe(struct mlx5_core_dev *mdev, u8 page_shift)
 {
-	return DIV_ROUND_UP(mlx5e_mpwrq_umr_wqe_sz(pages_per_wqe), MLX5_SEND_WQE_BB);
+	/* Add another page as a buffer between WQEs. This page will absorb
+	 * write overflow by the hardware, when receiving packets larger than
+	 * MTU. These oversize packets are dropped by the driver at a later
+	 * stage.
+	 */
+	return MLX5_ALIGN_MTTS(mlx5e_mpwrq_pages_per_wqe(mdev, page_shift) + 1);
+}
+
+static u8 mlx5e_mpwrq_max_log_rq_size(struct mlx5_core_dev *mdev, u8 page_shift)
+{
+	u8 mtts_per_wqe = mlx5e_mpwrq_mtts_per_wqe(mdev, page_shift);
+
+	return ilog2(MLX5E_MAX_RQ_NUM_MTTS / mtts_per_wqe);
+}
+
+u8 mlx5e_mpwrq_max_log_rq_pkts(struct mlx5_core_dev *mdev, u8 page_shift)
+{
+	return mlx5e_mpwrq_max_log_rq_size(mdev, page_shift) +
+		mlx5e_mpwrq_log_wqe_sz(mdev, page_shift) -
+		MLX5E_ORDER2_MAX_PACKET_MTU;
 }
 
 u16 mlx5e_get_linear_rq_headroom(struct mlx5e_params *params,
@@ -52,14 +133,16 @@ static u32 mlx5e_rx_get_linear_sz_skb(struct mlx5e_params *params, bool xsk)
 	return MLX5_SKB_FRAG_SZ(headroom + hw_mtu);
 }
 
-static u32 mlx5e_rx_get_linear_stride_sz(struct mlx5e_params *params,
-					 struct mlx5e_xsk_param *xsk)
+static u32 mlx5e_rx_get_linear_stride_sz(struct mlx5_core_dev *mdev,
+					 struct mlx5e_params *params,
+					 struct mlx5e_xsk_param *xsk,
+					 bool mpwqe)
 {
 	/* XSK frames are mapped as individual pages, because frames may come in
 	 * an arbitrary order from random locations in the UMEM.
 	 */
 	if (xsk)
-		return PAGE_SIZE;
+		return mpwqe ? 1 << mlx5e_mpwrq_page_shift(mdev, xsk) : PAGE_SIZE;
 
 	/* XDP in mlx5e doesn't support multiple packets per page. */
 	if (params->xdp_prog)
@@ -68,15 +151,18 @@ static u32 mlx5e_rx_get_linear_stride_sz(struct mlx5e_params *params,
 	return roundup_pow_of_two(mlx5e_rx_get_linear_sz_skb(params, false));
 }
 
-static u8 mlx5e_mpwqe_log_pkts_per_wqe(struct mlx5e_params *params,
+static u8 mlx5e_mpwqe_log_pkts_per_wqe(struct mlx5_core_dev *mdev,
+				       struct mlx5e_params *params,
 				       struct mlx5e_xsk_param *xsk)
 {
-	u32 linear_stride_sz = mlx5e_rx_get_linear_stride_sz(params, xsk);
+	u32 linear_stride_sz = mlx5e_rx_get_linear_stride_sz(mdev, params, xsk, true);
+	u8 page_shift = mlx5e_mpwrq_page_shift(mdev, xsk);
 
-	return MLX5_MPWRQ_LOG_WQE_SZ - order_base_2(linear_stride_sz);
+	return mlx5e_mpwrq_log_wqe_sz(mdev, page_shift) - order_base_2(linear_stride_sz);
 }
 
-bool mlx5e_rx_is_linear_skb(struct mlx5e_params *params,
+bool mlx5e_rx_is_linear_skb(struct mlx5_core_dev *mdev,
+			    struct mlx5e_params *params,
 			    struct mlx5e_xsk_param *xsk)
 {
 	if (params->packet_merge.type != MLX5E_PACKET_MERGE_NONE)
@@ -96,9 +182,10 @@ bool mlx5e_rx_is_linear_skb(struct mlx5e_params *params,
 }
 
 static bool mlx5e_verify_rx_mpwqe_strides(struct mlx5_core_dev *mdev,
-					  u8 log_stride_sz, u8 log_num_strides)
+					  u8 log_stride_sz, u8 log_num_strides,
+					  u8 page_shift)
 {
-	if (log_stride_sz + log_num_strides != MLX5_MPWRQ_LOG_WQE_SZ)
+	if (log_stride_sz + log_num_strides != mlx5e_mpwrq_log_wqe_sz(mdev, page_shift))
 		return false;
 
 	if (log_stride_sz < MLX5_MPWQE_LOG_STRIDE_SZ_BASE ||
@@ -118,28 +205,50 @@ bool mlx5e_rx_mpwqe_is_linear_skb(struct mlx5_core_dev *mdev,
 				  struct mlx5e_params *params,
 				  struct mlx5e_xsk_param *xsk)
 {
-	s8 log_num_strides;
+	u8 page_shift = mlx5e_mpwrq_page_shift(mdev, xsk);
+	u8 log_num_strides;
 	u8 log_stride_sz;
+	u8 log_wqe_sz;
 
-	if (!mlx5e_rx_is_linear_skb(params, xsk))
+	if (!mlx5e_rx_is_linear_skb(mdev, params, xsk))
 		return false;
 
-	log_stride_sz = order_base_2(mlx5e_rx_get_linear_stride_sz(params, xsk));
-	log_num_strides = MLX5_MPWRQ_LOG_WQE_SZ - log_stride_sz;
+	log_stride_sz = order_base_2(mlx5e_rx_get_linear_stride_sz(mdev, params, xsk, true));
+	log_wqe_sz = mlx5e_mpwrq_log_wqe_sz(mdev, page_shift);
 
-	return mlx5e_verify_rx_mpwqe_strides(mdev, log_stride_sz, log_num_strides);
+	if (log_wqe_sz < log_stride_sz)
+		return false;
+
+	log_num_strides = log_wqe_sz - log_stride_sz;
+
+	return mlx5e_verify_rx_mpwqe_strides(mdev, log_stride_sz,
+					     log_num_strides, page_shift);
 }
 
-u8 mlx5e_mpwqe_get_log_rq_size(struct mlx5e_params *params,
+u8 mlx5e_mpwqe_get_log_rq_size(struct mlx5_core_dev *mdev,
+			       struct mlx5e_params *params,
 			       struct mlx5e_xsk_param *xsk)
 {
-	u8 log_pkts_per_wqe = mlx5e_mpwqe_log_pkts_per_wqe(params, xsk);
+	u8 log_pkts_per_wqe, page_shift, max_log_rq_size;
+
+	log_pkts_per_wqe = mlx5e_mpwqe_log_pkts_per_wqe(mdev, params, xsk);
+	page_shift = mlx5e_mpwrq_page_shift(mdev, xsk);
+	max_log_rq_size = mlx5e_mpwrq_max_log_rq_size(mdev, page_shift);
 
 	/* Numbers are unsigned, don't subtract to avoid underflow. */
 	if (params->log_rq_mtu_frames <
 	    log_pkts_per_wqe + MLX5E_PARAMS_MINIMUM_LOG_RQ_SIZE_MPW)
 		return MLX5E_PARAMS_MINIMUM_LOG_RQ_SIZE_MPW;
 
+	/* Ethtool's rx_max_pending is calculated for regular RQ, that uses
+	 * pages of PAGE_SIZE. Max length of an XSK RQ might differ if it uses a
+	 * frame size not equal to PAGE_SIZE.
+	 * A stricter condition is checked in mlx5e_mpwrq_validate_xsk, WARN on
+	 * unexpected failure.
+	 */
+	if (WARN_ON_ONCE(params->log_rq_mtu_frames > log_pkts_per_wqe + max_log_rq_size))
+		return max_log_rq_size;
+
 	return params->log_rq_mtu_frames - log_pkts_per_wqe;
 }
 
@@ -169,7 +278,7 @@ u8 mlx5e_mpwqe_get_log_stride_size(struct mlx5_core_dev *mdev,
 				   struct mlx5e_xsk_param *xsk)
 {
 	if (mlx5e_rx_mpwqe_is_linear_skb(mdev, params, xsk))
-		return order_base_2(mlx5e_rx_get_linear_stride_sz(params, xsk));
+		return order_base_2(mlx5e_rx_get_linear_stride_sz(mdev, params, xsk, true));
 
 	return MLX5_MPWRQ_DEF_LOG_STRIDE_SZ(mdev);
 }
@@ -178,7 +287,9 @@ u8 mlx5e_mpwqe_get_log_num_strides(struct mlx5_core_dev *mdev,
 				   struct mlx5e_params *params,
 				   struct mlx5e_xsk_param *xsk)
 {
-	return MLX5_MPWRQ_LOG_WQE_SZ -
+	u8 page_shift = mlx5e_mpwrq_page_shift(mdev, xsk);
+
+	return mlx5e_mpwrq_log_wqe_sz(mdev, page_shift) -
 		mlx5e_mpwqe_get_log_stride_size(mdev, params, xsk);
 }
 
@@ -327,7 +438,9 @@ bool slow_pci_heuristic(struct mlx5_core_dev *mdev)
 
 int mlx5e_mpwrq_validate_regular(struct mlx5_core_dev *mdev, struct mlx5e_params *params)
 {
-	if (!mlx5e_check_fragmented_striding_rq_cap(mdev))
+	u8 page_shift = mlx5e_mpwrq_page_shift(mdev, NULL);
+
+	if (!mlx5e_check_fragmented_striding_rq_cap(mdev, page_shift))
 		return -EOPNOTSUPP;
 
 	if (params->xdp_prog && !mlx5e_rx_mpwqe_is_linear_skb(mdev, params, NULL))
@@ -339,12 +452,26 @@ int mlx5e_mpwrq_validate_regular(struct mlx5_core_dev *mdev, struct mlx5e_params
 int mlx5e_mpwrq_validate_xsk(struct mlx5_core_dev *mdev, struct mlx5e_params *params,
 			     struct mlx5e_xsk_param *xsk)
 {
-	if (!mlx5e_check_fragmented_striding_rq_cap(mdev))
+	u8 page_shift = mlx5e_mpwrq_page_shift(mdev, xsk);
+	u16 max_mtu_pkts;
+
+	if (!mlx5e_check_fragmented_striding_rq_cap(mdev, page_shift))
 		return -EOPNOTSUPP;
 
 	if (!mlx5e_rx_mpwqe_is_linear_skb(mdev, params, xsk))
 		return -EINVAL;
 
+	/* Current RQ length is too big for the given frame size, the
+	 * needed number of WQEs exceeds the maximum.
+	 */
+	max_mtu_pkts = min_t(u8, MLX5E_PARAMS_MAXIMUM_LOG_RQ_SIZE,
+			     mlx5e_mpwrq_max_log_rq_pkts(mdev, page_shift));
+	if (params->log_rq_mtu_frames > max_mtu_pkts) {
+		mlx5_core_err(mdev, "Current RQ length %d is too big for XSK with given frame size %u\n",
+			      1 << params->log_rq_mtu_frames, xsk->chunk_size);
+		return -EINVAL;
+	}
+
 	return 0;
 }
 
@@ -358,7 +485,7 @@ void mlx5e_init_rq_type_params(struct mlx5_core_dev *mdev,
 	mlx5_core_info(mdev, "MLX5E: StrdRq(%d) RqSz(%ld) StrdSz(%ld) RxCqeCmprss(%d)\n",
 		       params->rq_wq_type == MLX5_WQ_TYPE_LINKED_LIST_STRIDING_RQ,
 		       params->rq_wq_type == MLX5_WQ_TYPE_LINKED_LIST_STRIDING_RQ ?
-		       BIT(mlx5e_mpwqe_get_log_rq_size(params, NULL)) :
+		       BIT(mlx5e_mpwqe_get_log_rq_size(mdev, params, NULL)) :
 		       BIT(params->log_rq_mtu_frames),
 		       BIT(mlx5e_mpwqe_get_log_stride_size(mdev, params, NULL)),
 		       MLX5E_GET_PFLAG(params, MLX5E_PFLAG_RX_CQE_COMPRESS));
@@ -385,7 +512,7 @@ void mlx5e_build_rq_params(struct mlx5_core_dev *mdev,
 	     MLX5_CAP_GEN(mdev, mini_cqe_resp_stride_index)) &&
 	    !mlx5e_mpwrq_validate_regular(mdev, params) &&
 	    (mlx5e_rx_mpwqe_is_linear_skb(mdev, params, NULL) ||
-	     !mlx5e_rx_is_linear_skb(params, NULL)))
+	     !mlx5e_rx_is_linear_skb(mdev, params, NULL)))
 		MLX5E_SET_PFLAG(params, MLX5E_PFLAG_RX_STRIDING_RQ, true);
 	mlx5e_set_rq_type(mdev, params);
 	mlx5e_init_rq_type_params(mdev, params);
@@ -428,10 +555,10 @@ static int mlx5e_build_rq_frags_info(struct mlx5_core_dev *mdev,
 	int max_mtu;
 	int i;
 
-	if (mlx5e_rx_is_linear_skb(params, xsk)) {
+	if (mlx5e_rx_is_linear_skb(mdev, params, xsk)) {
 		int frag_stride;
 
-		frag_stride = mlx5e_rx_get_linear_stride_sz(params, xsk);
+		frag_stride = mlx5e_rx_get_linear_stride_sz(mdev, params, xsk, false);
 
 		info->arr[0].frag_size = byte_count;
 		info->arr[0].frag_stride = frag_stride;
@@ -528,7 +655,7 @@ static u32 mlx5e_shampo_get_log_cq_size(struct mlx5_core_dev *mdev,
 	u16 num_strides = BIT(mlx5e_mpwqe_get_log_num_strides(mdev, params, xsk));
 	int pkt_per_rsrv = BIT(mlx5e_shampo_get_log_pkt_per_rsrv(mdev, params));
 	u8 log_stride_sz = mlx5e_mpwqe_get_log_stride_size(mdev, params, xsk);
-	int wq_size = BIT(mlx5e_mpwqe_get_log_rq_size(params, xsk));
+	int wq_size = BIT(mlx5e_mpwqe_get_log_rq_size(mdev, params, xsk));
 	int wqe_size = BIT(log_stride_sz) * num_strides;
 
 	/* +1 is for the case that the pkt_per_rsrv dont consume the reservation
@@ -552,7 +679,7 @@ static void mlx5e_build_rx_cq_param(struct mlx5_core_dev *mdev,
 		if (params->packet_merge.type == MLX5E_PACKET_MERGE_SHAMPO)
 			log_cq_size = mlx5e_shampo_get_log_cq_size(mdev, params, xsk);
 		else
-			log_cq_size = mlx5e_mpwqe_get_log_rq_size(params, xsk) +
+			log_cq_size = mlx5e_mpwqe_get_log_rq_size(mdev, params, xsk) +
 				mlx5e_mpwqe_get_log_num_strides(mdev, params, xsk);
 		break;
 	default: /* MLX5_WQ_TYPE_CYCLIC */
@@ -595,9 +722,11 @@ int mlx5e_build_rq_param(struct mlx5_core_dev *mdev,
 	case MLX5_WQ_TYPE_LINKED_LIST_STRIDING_RQ: {
 		u8 log_wqe_num_of_strides = mlx5e_mpwqe_get_log_num_strides(mdev, params, xsk);
 		u8 log_wqe_stride_size = mlx5e_mpwqe_get_log_stride_size(mdev, params, xsk);
+		u8 page_shift = mlx5e_mpwrq_page_shift(mdev, xsk);
 
 		if (!mlx5e_verify_rx_mpwqe_strides(mdev, log_wqe_stride_size,
-						   log_wqe_num_of_strides)) {
+						   log_wqe_num_of_strides,
+						   page_shift)) {
 			mlx5_core_err(mdev,
 				      "Bad RX MPWQE params: log_stride_size %u, log_num_strides %u\n",
 				      log_wqe_stride_size, log_wqe_num_of_strides);
@@ -608,7 +737,7 @@ int mlx5e_build_rq_param(struct mlx5_core_dev *mdev,
 			 log_wqe_num_of_strides - MLX5_MPWQE_LOG_NUM_STRIDES_BASE);
 		MLX5_SET(wq, wq, log_wqe_stride_size,
 			 log_wqe_stride_size - MLX5_MPWQE_LOG_STRIDE_SZ_BASE);
-		MLX5_SET(wq, wq, log_wq_sz, mlx5e_mpwqe_get_log_rq_size(params, xsk));
+		MLX5_SET(wq, wq, log_wq_sz, mlx5e_mpwqe_get_log_rq_size(mdev, params, xsk));
 		if (params->packet_merge.type == MLX5E_PACKET_MERGE_SHAMPO) {
 			MLX5_SET(wq, wq, shampo_enable, true);
 			MLX5_SET(wq, wq, log_reservation_size,
@@ -797,7 +926,8 @@ static u8 mlx5e_build_icosq_log_wq_sz(struct mlx5_core_dev *mdev,
 	if (params->rq_wq_type != MLX5_WQ_TYPE_LINKED_LIST_STRIDING_RQ)
 		return MLX5E_PARAMS_MINIMUM_LOG_SQ_SIZE;
 
-	wqebbs = mlx5e_mpwrq_umr_wqebbs(MLX5_MPWRQ_PAGES_PER_WQE) *
+	/* UMR WQEs for the regular RQ. */
+	wqebbs = mlx5e_mpwrq_umr_wqebbs(mdev, PAGE_SHIFT) *
 		(1 << mlx5e_get_rq_log_wq_sz(rqp->rqc));
 
 	/* If XDP program is attached, XSK may be turned on at any time without
@@ -866,7 +996,7 @@ void mlx5e_build_xdpsq_param(struct mlx5_core_dev *mdev,
 	mlx5e_build_sq_param_common(mdev, param);
 	MLX5_SET(wq, wq, log_wq_sz, params->log_sq_size);
 	param->is_mpw = MLX5E_GET_PFLAG(params, MLX5E_PFLAG_XDP_TX_MPWQE);
-	param->is_xdp_mb = !mlx5e_rx_is_linear_skb(params, xsk);
+	param->is_xdp_mb = !mlx5e_rx_is_linear_skb(mdev, params, xsk);
 	mlx5e_build_tx_cq_param(mdev, params, &param->cqp);
 }