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
24u32 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, rxq: &nvchan->xdp_rxq);
57 xdp_prepare_buff(xdp, page_address(page), NETVSC_XDP_HDRM, data_len: len, meta_valid: 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(dev: ndev, xdp, prog)) {
74 nvchan->xdp_flush = true;
75 drop = false;
76
77 u64_stats_update_begin(syncp: &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(syncp: &rx_stats->syncp);
84
85 break;
86 } else {
87 u64_stats_update_begin(syncp: &rx_stats->syncp);
88 rx_stats->xdp_drop++;
89 u64_stats_update_end(syncp: &rx_stats->syncp);
90 }
91
92 fallthrough;
93
94 case XDP_ABORTED:
95 trace_xdp_exception(dev: ndev, xdp: prog, act);
96 break;
97
98 default:
99 bpf_warn_invalid_xdp_action(dev: ndev, prog, act);
100 }
101
102out:
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
113unsigned 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
119struct bpf_prog *netvsc_xdp_get(struct netvsc_device *nvdev)
120{
121 return rtnl_dereference(nvdev->chan_table[0].bpf_prog);
122}
123
124int 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(len: dev->mtu + ETH_HLEN);
137 if (prog && buf_max > PAGE_SIZE) {
138 netdev_err(dev, format: "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, format: "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, i: 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(prog: old_prog);
161
162 return 0;
163}
164
165int 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 = netif_xdp_propagate(dev: vf_netdev, bpf: &xdp);
187
188 if (ret && prog)
189 bpf_prog_put(prog);
190
191 return ret;
192}
193
194int 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, prog: bpf->prog, extack, nvdev);
209
210 if (ret)
211 return ret;
212
213 ret = netvsc_vf_setxdp(vf_netdev, prog: bpf->prog);
214
215 if (ret) {
216 netdev_err(dev, format: "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
229static 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(xdpf: frame, dev: ndev);
235 if (unlikely(!skb))
236 return -ENOMEM;
237
238 netvsc_get_hash(skb, ndc: netdev_priv(dev: ndev));
239
240 skb_record_rx_queue(skb, rx_queue: q_idx);
241
242 netvsc_xdp_xmit(skb, ndev);
243
244 return 0;
245}
246
247int 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(dev: 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(dev: vf_netdev) &&
269 netif_carrier_ok(dev: vf_netdev) && !netpoll_tx_running(dev: 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, frame: 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(syncp: &tx_stats->syncp);
288 tx_stats->xdp_xmit += count;
289 u64_stats_update_end(syncp: &tx_stats->syncp);
290
291 return count;
292}
293

source code of linux/drivers/net/hyperv/netvsc_bpf.c