1 // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
2 /* Copyright (c) 2019 Mellanox Technologies. */
3 
4 #include "setup.h"
5 #include "en/params.h"
6 #include "en/txrx.h"
7 
8 /* It matches XDP_UMEM_MIN_CHUNK_SIZE, but as this constant is private and may
9  * change unexpectedly, and mlx5e has a minimum valid stride size for striding
10  * RQ, keep this check in the driver.
11  */
12 #define MLX5E_MIN_XSK_CHUNK_SIZE 2048
13 
14 bool mlx5e_validate_xsk_param(struct mlx5e_params *params,
15 			      struct mlx5e_xsk_param *xsk,
16 			      struct mlx5_core_dev *mdev)
17 {
18 	/* AF_XDP doesn't support frames larger than PAGE_SIZE. */
19 	if (xsk->chunk_size > PAGE_SIZE ||
20 			xsk->chunk_size < MLX5E_MIN_XSK_CHUNK_SIZE)
21 		return false;
22 
23 	/* Current MTU and XSK headroom don't allow packets to fit the frames. */
24 	if (mlx5e_rx_get_min_frag_sz(params, xsk) > xsk->chunk_size)
25 		return false;
26 
27 	/* frag_sz is different for regular and XSK RQs, so ensure that linear
28 	 * SKB mode is possible.
29 	 */
30 	switch (params->rq_wq_type) {
31 	case MLX5_WQ_TYPE_LINKED_LIST_STRIDING_RQ:
32 		return mlx5e_rx_mpwqe_is_linear_skb(mdev, params, xsk);
33 	default: /* MLX5_WQ_TYPE_CYCLIC */
34 		return mlx5e_rx_is_linear_skb(params, xsk);
35 	}
36 }
37 
38 static void mlx5e_build_xsk_cparam(struct mlx5e_priv *priv,
39 				   struct mlx5e_params *params,
40 				   struct mlx5e_xsk_param *xsk,
41 				   struct mlx5e_channel_param *cparam)
42 {
43 	mlx5e_build_rq_param(priv, params, xsk, &cparam->rq);
44 	mlx5e_build_xdpsq_param(priv, params, &cparam->xdp_sq);
45 }
46 
47 int mlx5e_open_xsk(struct mlx5e_priv *priv, struct mlx5e_params *params,
48 		   struct mlx5e_xsk_param *xsk, struct xsk_buff_pool *pool,
49 		   struct mlx5e_channel *c)
50 {
51 	struct mlx5e_channel_param *cparam;
52 	struct mlx5e_create_cq_param ccp;
53 	int err;
54 
55 	mlx5e_build_create_cq_param(&ccp, c);
56 
57 	if (!mlx5e_validate_xsk_param(params, xsk, priv->mdev))
58 		return -EINVAL;
59 
60 	cparam = kvzalloc(sizeof(*cparam), GFP_KERNEL);
61 	if (!cparam)
62 		return -ENOMEM;
63 
64 	mlx5e_build_xsk_cparam(priv, params, xsk, cparam);
65 
66 	err = mlx5e_open_cq(c->priv, params->rx_cq_moderation, &cparam->rq.cqp, &ccp,
67 			    &c->xskrq.cq);
68 	if (unlikely(err))
69 		goto err_free_cparam;
70 
71 	err = mlx5e_open_rq(c, params, &cparam->rq, xsk, pool, &c->xskrq);
72 	if (unlikely(err))
73 		goto err_close_rx_cq;
74 
75 	err = mlx5e_open_cq(c->priv, params->tx_cq_moderation, &cparam->xdp_sq.cqp, &ccp,
76 			    &c->xsksq.cq);
77 	if (unlikely(err))
78 		goto err_close_rq;
79 
80 	/* Create a separate SQ, so that when the buff pool is disabled, we could
81 	 * close this SQ safely and stop receiving CQEs. In other case, e.g., if
82 	 * the XDPSQ was used instead, we might run into trouble when the buff pool
83 	 * is disabled and then reenabled, but the SQ continues receiving CQEs
84 	 * from the old buff pool.
85 	 */
86 	err = mlx5e_open_xdpsq(c, params, &cparam->xdp_sq, pool, &c->xsksq, true);
87 	if (unlikely(err))
88 		goto err_close_tx_cq;
89 
90 	kvfree(cparam);
91 
92 	set_bit(MLX5E_CHANNEL_STATE_XSK, c->state);
93 
94 	return 0;
95 
96 err_close_tx_cq:
97 	mlx5e_close_cq(&c->xsksq.cq);
98 
99 err_close_rq:
100 	mlx5e_close_rq(&c->xskrq);
101 
102 err_close_rx_cq:
103 	mlx5e_close_cq(&c->xskrq.cq);
104 
105 err_free_cparam:
106 	kvfree(cparam);
107 
108 	return err;
109 }
110 
111 void mlx5e_close_xsk(struct mlx5e_channel *c)
112 {
113 	clear_bit(MLX5E_CHANNEL_STATE_XSK, c->state);
114 	synchronize_rcu(); /* Sync with the XSK wakeup and with NAPI. */
115 
116 	mlx5e_close_rq(&c->xskrq);
117 	mlx5e_close_cq(&c->xskrq.cq);
118 	mlx5e_close_xdpsq(&c->xsksq);
119 	mlx5e_close_cq(&c->xsksq.cq);
120 
121 	memset(&c->xskrq, 0, sizeof(c->xskrq));
122 	memset(&c->xsksq, 0, sizeof(c->xsksq));
123 }
124 
125 void mlx5e_activate_xsk(struct mlx5e_channel *c)
126 {
127 	set_bit(MLX5E_RQ_STATE_ENABLED, &c->xskrq.state);
128 	/* TX queue is created active. */
129 
130 	spin_lock_bh(&c->async_icosq_lock);
131 	mlx5e_trigger_irq(&c->async_icosq);
132 	spin_unlock_bh(&c->async_icosq_lock);
133 }
134 
135 void mlx5e_deactivate_xsk(struct mlx5e_channel *c)
136 {
137 	mlx5e_deactivate_rq(&c->xskrq);
138 	/* TX queue is disabled on close. */
139 }
140 
141 static int mlx5e_redirect_xsk_rqt(struct mlx5e_priv *priv, u16 ix, u32 rqn)
142 {
143 	struct mlx5e_redirect_rqt_param direct_rrp = {
144 		.is_rss = false,
145 		{
146 			.rqn = rqn,
147 		},
148 	};
149 
150 	u32 rqtn = priv->xsk_tir[ix].rqt.rqtn;
151 
152 	return mlx5e_redirect_rqt(priv, rqtn, 1, direct_rrp);
153 }
154 
155 int mlx5e_xsk_redirect_rqt_to_channel(struct mlx5e_priv *priv, struct mlx5e_channel *c)
156 {
157 	return mlx5e_redirect_xsk_rqt(priv, c->ix, c->xskrq.rqn);
158 }
159 
160 int mlx5e_xsk_redirect_rqt_to_drop(struct mlx5e_priv *priv, u16 ix)
161 {
162 	return mlx5e_redirect_xsk_rqt(priv, ix, priv->drop_rq.rqn);
163 }
164 
165 int mlx5e_xsk_redirect_rqts_to_channels(struct mlx5e_priv *priv, struct mlx5e_channels *chs)
166 {
167 	int err, i;
168 
169 	if (!priv->xsk.refcnt)
170 		return 0;
171 
172 	for (i = 0; i < chs->num; i++) {
173 		struct mlx5e_channel *c = chs->c[i];
174 
175 		if (!test_bit(MLX5E_CHANNEL_STATE_XSK, c->state))
176 			continue;
177 
178 		err = mlx5e_xsk_redirect_rqt_to_channel(priv, c);
179 		if (unlikely(err))
180 			goto err_stop;
181 	}
182 
183 	return 0;
184 
185 err_stop:
186 	for (i--; i >= 0; i--) {
187 		if (!test_bit(MLX5E_CHANNEL_STATE_XSK, chs->c[i]->state))
188 			continue;
189 
190 		mlx5e_xsk_redirect_rqt_to_drop(priv, i);
191 	}
192 
193 	return err;
194 }
195 
196 void mlx5e_xsk_redirect_rqts_to_drop(struct mlx5e_priv *priv, struct mlx5e_channels *chs)
197 {
198 	int i;
199 
200 	if (!priv->xsk.refcnt)
201 		return;
202 
203 	for (i = 0; i < chs->num; i++) {
204 		if (!test_bit(MLX5E_CHANNEL_STATE_XSK, chs->c[i]->state))
205 			continue;
206 
207 		mlx5e_xsk_redirect_rqt_to_drop(priv, i);
208 	}
209 }
210