aboutsummaryrefslogtreecommitdiffstats
path: root/examples/vhost/virtio_net.c
blob: cc2c3d8827653a8b57002974416eb22748e68bbd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
/*-
 *   BSD LICENSE
 *
 *   Copyright(c) 2010-2017 Intel Corporation. All rights reserved.
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdint.h>
#include <stdbool.h>
#include <linux/virtio_net.h>

#include <rte_mbuf.h>
#include <rte_memcpy.h>
#include <rte_vhost.h>

#include "main.h"

/*
 * A very simple vhost-user net driver implementation, without
 * any extra features being enabled, such as TSO and mrg-Rx.
 */

void
vs_vhost_net_setup(struct vhost_dev *dev)
{
	uint16_t i;
	int vid = dev->vid;
	struct vhost_queue *queue;

	RTE_LOG(INFO, VHOST_CONFIG,
		"setting builtin vhost-user net driver\n");

	rte_vhost_get_negotiated_features(vid, &dev->features);
	if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF))
		dev->hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
	else
		dev->hdr_len = sizeof(struct virtio_net_hdr);

	rte_vhost_get_mem_table(vid, &dev->mem);

	dev->nr_vrings = rte_vhost_get_vring_num(vid);
	for (i = 0; i < dev->nr_vrings; i++) {
		queue = &dev->queues[i];

		queue->last_used_idx  = 0;
		queue->last_avail_idx = 0;
		rte_vhost_get_vhost_vring(vid, i, &queue->vr);
	}
}

void
vs_vhost_net_remove(struct vhost_dev *dev)
{
	free(dev->mem);
}

static inline int __attribute__((always_inline))
enqueue_pkt(struct vhost_dev *dev, struct rte_vhost_vring *vr,
	    struct rte_mbuf *m, uint16_t desc_idx)
{
	uint32_t desc_avail, desc_offset;
	uint32_t mbuf_avail, mbuf_offset;
	uint32_t cpy_len;
	struct vring_desc *desc;
	uint64_t desc_addr;
	struct virtio_net_hdr virtio_hdr = {0, 0, 0, 0, 0, 0};
	/* A counter to avoid desc dead loop chain */
	uint16_t nr_desc = 1;

	desc = &vr->desc[desc_idx];
	desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
	/*
	 * Checking of 'desc_addr' placed outside of 'unlikely' macro to avoid
	 * performance issue with some versions of gcc (4.8.4 and 5.3.0) which
	 * otherwise stores offset on the stack instead of in a register.
	 */
	if (unlikely(desc->len < dev->hdr_len) || !desc_addr)
		return -1;

	rte_prefetch0((void *)(uintptr_t)desc_addr);

	/* write virtio-net header */
	*(struct virtio_net_hdr *)(uintptr_t)desc_addr = virtio_hdr;

	desc_offset = dev->hdr_len;
	desc_avail  = desc->len - dev->hdr_len;

	mbuf_avail  = rte_pktmbuf_data_len(m);
	mbuf_offset = 0;
	while (mbuf_avail != 0 || m->next != NULL) {
		/* done with current mbuf, fetch next */
		if (mbuf_avail == 0) {
			m = m->next;

			mbuf_offset = 0;
			mbuf_avail  = rte_pktmbuf_data_len(m);
		}

		/* done with current desc buf, fetch next */
		if (desc_avail == 0) {
			if ((desc->flags & VRING_DESC_F_NEXT) == 0) {
				/* Room in vring buffer is not enough */
				return -1;
			}
			if (unlikely(desc->next >= vr->size ||
				     ++nr_desc > vr->size))
				return -1;

			desc = &vr->desc[desc->next];
			desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
			if (unlikely(!desc_addr))
				return -1;

			desc_offset = 0;
			desc_avail  = desc->len;
		}

		cpy_len = RTE_MIN(desc_avail, mbuf_avail);
		rte_memcpy((void *)((uintptr_t)(desc_addr + desc_offset)),
			rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
			cpy_len);

		mbuf_avail  -= cpy_len;
		mbuf_offset += cpy_len;
		desc_avail  -= cpy_len;
		desc_offset += cpy_len;
	}

	return 0;
}

uint16_t
vs_enqueue_pkts(struct vhost_dev *dev, uint16_t queue_id,
		struct rte_mbuf **pkts, uint32_t count)
{
	struct vhost_queue *queue;
	struct rte_vhost_vring *vr;
	uint16_t avail_idx, free_entries, start_idx;
	uint16_t desc_indexes[MAX_PKT_BURST];
	uint16_t used_idx;
	uint32_t i;

	queue = &dev->queues[queue_id];
	vr    = &queue->vr;

	avail_idx = *((volatile uint16_t *)&vr->avail->idx);
	start_idx = queue->last_used_idx;
	free_entries = avail_idx - start_idx;
	count = RTE_MIN(count, free_entries);
	count = RTE_MIN(count, (uint32_t)MAX_PKT_BURST);
	if (count == 0)
		return 0;

	/* Retrieve all of the desc indexes first to avoid caching issues. */
	rte_prefetch0(&vr->avail->ring[start_idx & (vr->size - 1)]);
	for (i = 0; i < count; i++) {
		used_idx = (start_idx + i) & (vr->size - 1);
		desc_indexes[i] = vr->avail->ring[used_idx];
		vr->used->ring[used_idx].id = desc_indexes[i];
		vr->used->ring[used_idx].len = pkts[i]->pkt_len +
					       dev->hdr_len;
	}

	rte_prefetch0(&vr->desc[desc_indexes[0]]);
	for (i = 0; i < count; i++) {
		uint16_t desc_idx = desc_indexes[i];
		int err;

		err = enqueue_pkt(dev, vr, pkts[i], desc_idx);
		if (unlikely(err)) {
			used_idx = (start_idx + i) & (vr->size - 1);
			vr->used->ring[used_idx].len = dev->hdr_len;
		}

		if (i + 1 < count)
			rte_prefetch0(&vr->desc[desc_indexes[i+1]]);
	}

	rte_smp_wmb();

	*(volatile uint16_t *)&vr->used->idx += count;
	queue->last_used_idx += count;

	/* flush used->idx update before we read avail->flags. */
	rte_mb();

	/* Kick the guest if necessary. */
	if (!(vr->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
			&& (vr->callfd >= 0))
		eventfd_write(vr->callfd, (eventfd_t)1);
	return count;
}

static inline int __attribute__((always_inline))
dequeue_pkt(struct vhost_dev *dev, struct rte_vhost_vring *vr,
	    struct rte_mbuf *m, uint16_t desc_idx,
	    struct rte_mempool *mbuf_pool)
{
	struct vring_desc *desc;
	uint64_t desc_addr;
	uint32_t desc_avail, desc_offset;
	uint32_t mbuf_avail, mbuf_offset;
	uint32_t cpy_len;
	struct rte_mbuf *cur = m, *prev = m;
	/* A counter to avoid desc dead loop chain */
	uint32_t nr_desc = 1;

	desc = &vr->desc[desc_idx];
	if (unlikely((desc->len < dev->hdr_len)) ||
			(desc->flags & VRING_DESC_F_INDIRECT))
		return -1;

	desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
	if (unlikely(!desc_addr))
		return -1;

	/*
	 * We don't support ANY_LAYOUT, neither VERSION_1, meaning
	 * a Tx packet from guest must have 2 desc buffers at least:
	 * the first for storing the header and the others for
	 * storing the data.
	 *
	 * And since we don't support TSO, we could simply skip the
	 * header.
	 */
	desc = &vr->desc[desc->next];
	desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
	if (unlikely(!desc_addr))
		return -1;
	rte_prefetch0((void *)(uintptr_t)desc_addr);

	desc_offset = 0;
	desc_avail  = desc->len;
	nr_desc    += 1;

	mbuf_offset = 0;
	mbuf_avail  = m->buf_len - RTE_PKTMBUF_HEADROOM;
	while (1) {
		cpy_len = RTE_MIN(desc_avail, mbuf_avail);
		rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *,
						   mbuf_offset),
			(void *)((uintptr_t)(desc_addr + desc_offset)),
			cpy_len);

		mbuf_avail  -= cpy_len;
		mbuf_offset += cpy_len;
		desc_avail  -= cpy_len;
		desc_offset += cpy_len;

		/* This desc reaches to its end, get the next one */
		if (desc_avail == 0) {
			if ((desc->flags & VRING_DESC_F_NEXT) == 0)
				break;

			if (unlikely(desc->next >= vr->size ||
				     ++nr_desc > vr->size))
				return -1;
			desc = &vr->desc[desc->next];

			desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
			if (unlikely(!desc_addr))
				return -1;
			rte_prefetch0((void *)(uintptr_t)desc_addr);

			desc_offset = 0;
			desc_avail  = desc->len;
		}

		/*
		 * This mbuf reaches to its end, get a new one
		 * to hold more data.
		 */
		if (mbuf_avail == 0) {
			cur = rte_pktmbuf_alloc(mbuf_pool);
			if (unlikely(cur == NULL)) {
				RTE_LOG(ERR, VHOST_DATA, "Failed to "
					"allocate memory for mbuf.\n");
				return -1;
			}

			prev->next = cur;
			prev->data_len = mbuf_offset;
			m->nb_segs += 1;
			m->pkt_len += mbuf_offset;
			prev = cur;

			mbuf_offset = 0;
			mbuf_avail  = cur->buf_len - RTE_PKTMBUF_HEADROOM;
		}
	}

	prev->data_len = mbuf_offset;
	m->pkt_len    += mbuf_offset;

	return 0;
}

uint16_t
vs_dequeue_pkts(struct vhost_dev *dev, uint16_t queue_id,
	struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count)
{
	struct vhost_queue *queue;
	struct rte_vhost_vring *vr;
	uint32_t desc_indexes[MAX_PKT_BURST];
	uint32_t used_idx;
	uint32_t i = 0;
	uint16_t free_entries;
	uint16_t avail_idx;

	queue = &dev->queues[queue_id];
	vr    = &queue->vr;

	free_entries = *((volatile uint16_t *)&vr->avail->idx) -
			queue->last_avail_idx;
	if (free_entries == 0)
		return 0;

	/* Prefetch available and used ring */
	avail_idx = queue->last_avail_idx & (vr->size - 1);
	used_idx  = queue->last_used_idx  & (vr->size - 1);
	rte_prefetch0(&vr->avail->ring[avail_idx]);
	rte_prefetch0(&vr->used->ring[used_idx]);

	count = RTE_MIN(count, MAX_PKT_BURST);
	count = RTE_MIN(count, free_entries);

	/*
	 * Retrieve all of the head indexes first and pre-update used entries
	 * to avoid caching issues.
	 */
	for (i = 0; i < count; i++) {
		avail_idx = (queue->last_avail_idx + i) & (vr->size - 1);
		used_idx  = (queue->last_used_idx  + i) & (vr->size - 1);
		desc_indexes[i] = vr->avail->ring[avail_idx];

		vr->used->ring[used_idx].id  = desc_indexes[i];
		vr->used->ring[used_idx].len = 0;
	}

	/* Prefetch descriptor index. */
	rte_prefetch0(&vr->desc[desc_indexes[0]]);
	for (i = 0; i < count; i++) {
		int err;

		if (likely(i + 1 < count))
			rte_prefetch0(&vr->desc[desc_indexes[i + 1]]);

		pkts[i] = rte_pktmbuf_alloc(mbuf_pool);
		if (unlikely(pkts[i] == NULL)) {
			RTE_LOG(ERR, VHOST_DATA,
				"Failed to allocate memory for mbuf.\n");
			break;
		}

		err = dequeue_pkt(dev, vr, pkts[i], desc_indexes[i], mbuf_pool);
		if (unlikely(err)) {
			rte_pktmbuf_free(pkts[i]);
			break;
		}

	}
	if (!i)
		return 0;

	queue->last_avail_idx += i;
	queue->last_used_idx += i;
	rte_smp_wmb();
	rte_smp_rmb();

	vr->used->idx += i;

	if (!(vr->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
			&& (vr->callfd >= 0))
		eventfd_write(vr->callfd, (eventfd_t)1);

	return i;
}