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/bpf.h>
 14#include <linux/bpf_trace.h>
 15#include <linux/kernel.h>
 16#include <net/xdp.h>
 17
 18#include <linux/mutex.h>
 19#include <linux/rtnetlink.h>
 20
 21#include "hyperv_net.h"
 22
 23u32 netvsc_run_xdp(struct net_device *ndev, struct netvsc_channel *nvchan,
 24		   struct xdp_buff *xdp)
 25{
 26	void *data = nvchan->rsc.data[0];
 27	u32 len = nvchan->rsc.len[0];
 28	struct page *page = NULL;
 29	struct bpf_prog *prog;
 30	u32 act = XDP_PASS;
 31
 32	xdp->data_hard_start = NULL;
 33
 34	rcu_read_lock();
 35	prog = rcu_dereference(nvchan->bpf_prog);
 36
 37	if (!prog)
 38		goto out;
 39
 40	/* allocate page buffer for data */
 41	page = alloc_page(GFP_ATOMIC);
 42	if (!page) {
 43		act = XDP_DROP;
 44		goto out;
 45	}
 46
 47	xdp->data_hard_start = page_address(page);
 48	xdp->data = xdp->data_hard_start + NETVSC_XDP_HDRM;
 49	xdp_set_data_meta_invalid(xdp);
 50	xdp->data_end = xdp->data + len;
 51	xdp->rxq = &nvchan->xdp_rxq;
 52	xdp->frame_sz = PAGE_SIZE;
 53
 54	memcpy(xdp->data, data, len);
 55
 56	act = bpf_prog_run_xdp(prog, xdp);
 57
 58	switch (act) {
 59	case XDP_PASS:
 60	case XDP_TX:
 61	case XDP_DROP:
 62		break;
 63
 64	case XDP_ABORTED:
 65		trace_xdp_exception(ndev, prog, act);
 66		break;
 67
 68	default:
 69		bpf_warn_invalid_xdp_action(act);
 70	}
 71
 72out:
 73	rcu_read_unlock();
 74
 75	if (page && act != XDP_PASS && act != XDP_TX) {
 76		__free_page(page);
 77		xdp->data_hard_start = NULL;
 78	}
 79
 80	return act;
 81}
 82
 83unsigned int netvsc_xdp_fraglen(unsigned int len)
 84{
 85	return SKB_DATA_ALIGN(len) +
 86	       SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 87}
 88
 89struct bpf_prog *netvsc_xdp_get(struct netvsc_device *nvdev)
 90{
 91	return rtnl_dereference(nvdev->chan_table[0].bpf_prog);
 92}
 93
 94int netvsc_xdp_set(struct net_device *dev, struct bpf_prog *prog,
 95		   struct netlink_ext_ack *extack,
 96		   struct netvsc_device *nvdev)
 97{
 98	struct bpf_prog *old_prog;
 99	int buf_max, i;
100
101	old_prog = netvsc_xdp_get(nvdev);
102
103	if (!old_prog && !prog)
104		return 0;
105
106	buf_max = NETVSC_XDP_HDRM + netvsc_xdp_fraglen(dev->mtu + ETH_HLEN);
107	if (prog && buf_max > PAGE_SIZE) {
108		netdev_err(dev, "XDP: mtu:%u too large, buf_max:%u\n",
109			   dev->mtu, buf_max);
110		NL_SET_ERR_MSG_MOD(extack, "XDP: mtu too large");
111
112		return -EOPNOTSUPP;
113	}
114
115	if (prog && (dev->features & NETIF_F_LRO)) {
116		netdev_err(dev, "XDP: not support LRO\n");
117		NL_SET_ERR_MSG_MOD(extack, "XDP: not support LRO");
118
119		return -EOPNOTSUPP;
120	}
121
122	if (prog)
123		bpf_prog_add(prog, nvdev->num_chn - 1);
124
125	for (i = 0; i < nvdev->num_chn; i++)
126		rcu_assign_pointer(nvdev->chan_table[i].bpf_prog, prog);
127
128	if (old_prog)
129		for (i = 0; i < nvdev->num_chn; i++)
130			bpf_prog_put(old_prog);
131
132	return 0;
133}
134
135int netvsc_vf_setxdp(struct net_device *vf_netdev, struct bpf_prog *prog)
136{
137	struct netdev_bpf xdp;
138	bpf_op_t ndo_bpf;
139	int ret;
140
141	ASSERT_RTNL();
142
143	if (!vf_netdev)
144		return 0;
145
146	ndo_bpf = vf_netdev->netdev_ops->ndo_bpf;
147	if (!ndo_bpf)
148		return 0;
149
150	memset(&xdp, 0, sizeof(xdp));
151
152	if (prog)
153		bpf_prog_inc(prog);
154
155	xdp.command = XDP_SETUP_PROG;
156	xdp.prog = prog;
157
158	ret = ndo_bpf(vf_netdev, &xdp);
159
160	if (ret && prog)
161		bpf_prog_put(prog);
162
163	return ret;
164}
165
166int netvsc_bpf(struct net_device *dev, struct netdev_bpf *bpf)
167{
168	struct net_device_context *ndevctx = netdev_priv(dev);
169	struct netvsc_device *nvdev = rtnl_dereference(ndevctx->nvdev);
170	struct net_device *vf_netdev = rtnl_dereference(ndevctx->vf_netdev);
171	struct netlink_ext_ack *extack = bpf->extack;
172	int ret;
173
174	if (!nvdev || nvdev->destroy) {
175		return -ENODEV;
176	}
177
178	switch (bpf->command) {
179	case XDP_SETUP_PROG:
180		ret = netvsc_xdp_set(dev, bpf->prog, extack, nvdev);
181
182		if (ret)
183			return ret;
184
185		ret = netvsc_vf_setxdp(vf_netdev, bpf->prog);
186
187		if (ret) {
188			netdev_err(dev, "vf_setxdp failed:%d\n", ret);
189			NL_SET_ERR_MSG_MOD(extack, "vf_setxdp failed");
190
191			netvsc_xdp_set(dev, NULL, extack, nvdev);
192		}
193
194		return ret;
195
196	default:
197		return -EINVAL;
198	}
199}