xref: /linux/drivers/net/hyperv/netvsc_bpf.c (revision e7d759f31ca295d589f7420719c311870bb3166f) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2019, Microsoft Corporation.
3  *
4  * Author:
5  *   Haiyang Zhang <haiyangz@microsoft.com>
6  */
7 
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9 
10 #include <linux/netdevice.h>
11 #include <linux/etherdevice.h>
12 #include <linux/ethtool.h>
13 #include <linux/netpoll.h>
14 #include <linux/bpf.h>
15 #include <linux/bpf_trace.h>
16 #include <linux/kernel.h>
17 #include <net/xdp.h>
18 
19 #include <linux/mutex.h>
20 #include <linux/rtnetlink.h>
21 
22 #include "hyperv_net.h"
23 
24 u32 netvsc_run_xdp(struct net_device *ndev, struct netvsc_channel *nvchan,
25 		   struct xdp_buff *xdp)
26 {
27 	struct netvsc_stats_rx *rx_stats = &nvchan->rx_stats;
28 	void *data = nvchan->rsc.data[0];
29 	u32 len = nvchan->rsc.len[0];
30 	struct page *page = NULL;
31 	struct bpf_prog *prog;
32 	u32 act = XDP_PASS;
33 	bool drop = true;
34 
35 	xdp->data_hard_start = NULL;
36 
37 	rcu_read_lock();
38 	prog = rcu_dereference(nvchan->bpf_prog);
39 
40 	if (!prog)
41 		goto out;
42 
43 	/* Ensure that the below memcpy() won't overflow the page buffer. */
44 	if (len > ndev->mtu + ETH_HLEN) {
45 		act = XDP_DROP;
46 		goto out;
47 	}
48 
49 	/* allocate page buffer for data */
50 	page = alloc_page(GFP_ATOMIC);
51 	if (!page) {
52 		act = XDP_DROP;
53 		goto out;
54 	}
55 
56 	xdp_init_buff(xdp, PAGE_SIZE, &nvchan->xdp_rxq);
57 	xdp_prepare_buff(xdp, page_address(page), NETVSC_XDP_HDRM, len, false);
58 
59 	memcpy(xdp->data, data, len);
60 
61 	act = bpf_prog_run_xdp(prog, xdp);
62 
63 	switch (act) {
64 	case XDP_PASS:
65 	case XDP_TX:
66 		drop = false;
67 		break;
68 
69 	case XDP_DROP:
70 		break;
71 
72 	case XDP_REDIRECT:
73 		if (!xdp_do_redirect(ndev, xdp, prog)) {
74 			nvchan->xdp_flush = true;
75 			drop = false;
76 
77 			u64_stats_update_begin(&rx_stats->syncp);
78 
79 			rx_stats->xdp_redirect++;
80 			rx_stats->packets++;
81 			rx_stats->bytes += nvchan->rsc.pktlen;
82 
83 			u64_stats_update_end(&rx_stats->syncp);
84 
85 			break;
86 		} else {
87 			u64_stats_update_begin(&rx_stats->syncp);
88 			rx_stats->xdp_drop++;
89 			u64_stats_update_end(&rx_stats->syncp);
90 		}
91 
92 		fallthrough;
93 
94 	case XDP_ABORTED:
95 		trace_xdp_exception(ndev, prog, act);
96 		break;
97 
98 	default:
99 		bpf_warn_invalid_xdp_action(ndev, prog, act);
100 	}
101 
102 out:
103 	rcu_read_unlock();
104 
105 	if (page && drop) {
106 		__free_page(page);
107 		xdp->data_hard_start = NULL;
108 	}
109 
110 	return act;
111 }
112 
113 unsigned int netvsc_xdp_fraglen(unsigned int len)
114 {
115 	return SKB_DATA_ALIGN(len) +
116 	       SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
117 }
118 
119 struct bpf_prog *netvsc_xdp_get(struct netvsc_device *nvdev)
120 {
121 	return rtnl_dereference(nvdev->chan_table[0].bpf_prog);
122 }
123 
124 int netvsc_xdp_set(struct net_device *dev, struct bpf_prog *prog,
125 		   struct netlink_ext_ack *extack,
126 		   struct netvsc_device *nvdev)
127 {
128 	struct bpf_prog *old_prog;
129 	int buf_max, i;
130 
131 	old_prog = netvsc_xdp_get(nvdev);
132 
133 	if (!old_prog && !prog)
134 		return 0;
135 
136 	buf_max = NETVSC_XDP_HDRM + netvsc_xdp_fraglen(dev->mtu + ETH_HLEN);
137 	if (prog && buf_max > PAGE_SIZE) {
138 		netdev_err(dev, "XDP: mtu:%u too large, buf_max:%u\n",
139 			   dev->mtu, buf_max);
140 		NL_SET_ERR_MSG_MOD(extack, "XDP: mtu too large");
141 
142 		return -EOPNOTSUPP;
143 	}
144 
145 	if (prog && (dev->features & NETIF_F_LRO)) {
146 		netdev_err(dev, "XDP: not support LRO\n");
147 		NL_SET_ERR_MSG_MOD(extack, "XDP: not support LRO");
148 
149 		return -EOPNOTSUPP;
150 	}
151 
152 	if (prog)
153 		bpf_prog_add(prog, nvdev->num_chn - 1);
154 
155 	for (i = 0; i < nvdev->num_chn; i++)
156 		rcu_assign_pointer(nvdev->chan_table[i].bpf_prog, prog);
157 
158 	if (old_prog)
159 		for (i = 0; i < nvdev->num_chn; i++)
160 			bpf_prog_put(old_prog);
161 
162 	return 0;
163 }
164 
165 int netvsc_vf_setxdp(struct net_device *vf_netdev, struct bpf_prog *prog)
166 {
167 	struct netdev_bpf xdp;
168 	int ret;
169 
170 	ASSERT_RTNL();
171 
172 	if (!vf_netdev)
173 		return 0;
174 
175 	if (!vf_netdev->netdev_ops->ndo_bpf)
176 		return 0;
177 
178 	memset(&xdp, 0, sizeof(xdp));
179 
180 	if (prog)
181 		bpf_prog_inc(prog);
182 
183 	xdp.command = XDP_SETUP_PROG;
184 	xdp.prog = prog;
185 
186 	ret = vf_netdev->netdev_ops->ndo_bpf(vf_netdev, &xdp);
187 
188 	if (ret && prog)
189 		bpf_prog_put(prog);
190 
191 	return ret;
192 }
193 
194 int netvsc_bpf(struct net_device *dev, struct netdev_bpf *bpf)
195 {
196 	struct net_device_context *ndevctx = netdev_priv(dev);
197 	struct netvsc_device *nvdev = rtnl_dereference(ndevctx->nvdev);
198 	struct net_device *vf_netdev = rtnl_dereference(ndevctx->vf_netdev);
199 	struct netlink_ext_ack *extack = bpf->extack;
200 	int ret;
201 
202 	if (!nvdev || nvdev->destroy) {
203 		return -ENODEV;
204 	}
205 
206 	switch (bpf->command) {
207 	case XDP_SETUP_PROG:
208 		ret = netvsc_xdp_set(dev, bpf->prog, extack, nvdev);
209 
210 		if (ret)
211 			return ret;
212 
213 		ret = netvsc_vf_setxdp(vf_netdev, bpf->prog);
214 
215 		if (ret) {
216 			netdev_err(dev, "vf_setxdp failed:%d\n", ret);
217 			NL_SET_ERR_MSG_MOD(extack, "vf_setxdp failed");
218 
219 			netvsc_xdp_set(dev, NULL, extack, nvdev);
220 		}
221 
222 		return ret;
223 
224 	default:
225 		return -EINVAL;
226 	}
227 }
228 
229 static int netvsc_ndoxdp_xmit_fm(struct net_device *ndev,
230 				 struct xdp_frame *frame, u16 q_idx)
231 {
232 	struct sk_buff *skb;
233 
234 	skb = xdp_build_skb_from_frame(frame, ndev);
235 	if (unlikely(!skb))
236 		return -ENOMEM;
237 
238 	netvsc_get_hash(skb, netdev_priv(ndev));
239 
240 	skb_record_rx_queue(skb, q_idx);
241 
242 	netvsc_xdp_xmit(skb, ndev);
243 
244 	return 0;
245 }
246 
247 int netvsc_ndoxdp_xmit(struct net_device *ndev, int n,
248 		       struct xdp_frame **frames, u32 flags)
249 {
250 	struct net_device_context *ndev_ctx = netdev_priv(ndev);
251 	const struct net_device_ops *vf_ops;
252 	struct netvsc_stats_tx *tx_stats;
253 	struct netvsc_device *nvsc_dev;
254 	struct net_device *vf_netdev;
255 	int i, count = 0;
256 	u16 q_idx;
257 
258 	/* Don't transmit if netvsc_device is gone */
259 	nvsc_dev = rcu_dereference_bh(ndev_ctx->nvdev);
260 	if (unlikely(!nvsc_dev || nvsc_dev->destroy))
261 		return 0;
262 
263 	/* If VF is present and up then redirect packets to it.
264 	 * Skip the VF if it is marked down or has no carrier.
265 	 * If netpoll is in uses, then VF can not be used either.
266 	 */
267 	vf_netdev = rcu_dereference_bh(ndev_ctx->vf_netdev);
268 	if (vf_netdev && netif_running(vf_netdev) &&
269 	    netif_carrier_ok(vf_netdev) && !netpoll_tx_running(ndev) &&
270 	    vf_netdev->netdev_ops->ndo_xdp_xmit &&
271 	    ndev_ctx->data_path_is_vf) {
272 		vf_ops = vf_netdev->netdev_ops;
273 		return vf_ops->ndo_xdp_xmit(vf_netdev, n, frames, flags);
274 	}
275 
276 	q_idx = smp_processor_id() % ndev->real_num_tx_queues;
277 
278 	for (i = 0; i < n; i++) {
279 		if (netvsc_ndoxdp_xmit_fm(ndev, frames[i], q_idx))
280 			break;
281 
282 		count++;
283 	}
284 
285 	tx_stats = &nvsc_dev->chan_table[q_idx].tx_stats;
286 
287 	u64_stats_update_begin(&tx_stats->syncp);
288 	tx_stats->xdp_xmit += count;
289 	u64_stats_update_end(&tx_stats->syncp);
290 
291 	return count;
292 }
293