xref: /dpdk/drivers/net/virtio/virtio_user/vhost_kernel.c (revision bbbe38a6d59ccdda25917712701e629d0b10af6f)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 2016 Intel Corporation
3  */
4 
5 #include <sys/types.h>
6 #include <sys/stat.h>
7 #include <fcntl.h>
8 #include <unistd.h>
9 #include <errno.h>
10 
11 #include <rte_memory.h>
12 
13 #include "vhost.h"
14 #include "virtio_user_dev.h"
15 #include "vhost_kernel_tap.h"
16 
17 struct vhost_kernel_data {
18 	int *vhostfds;
19 	int *tapfds;
20 };
21 
22 struct vhost_memory_kernel {
23 	uint32_t nregions;
24 	uint32_t padding;
25 	struct vhost_memory_region regions[0];
26 };
27 
28 /* vhost kernel ioctls */
29 #define VHOST_VIRTIO 0xAF
30 #define VHOST_GET_FEATURES _IOR(VHOST_VIRTIO, 0x00, __u64)
31 #define VHOST_SET_FEATURES _IOW(VHOST_VIRTIO, 0x00, __u64)
32 #define VHOST_SET_OWNER _IO(VHOST_VIRTIO, 0x01)
33 #define VHOST_RESET_OWNER _IO(VHOST_VIRTIO, 0x02)
34 #define VHOST_SET_MEM_TABLE _IOW(VHOST_VIRTIO, 0x03, struct vhost_memory_kernel)
35 #define VHOST_SET_LOG_BASE _IOW(VHOST_VIRTIO, 0x04, __u64)
36 #define VHOST_SET_LOG_FD _IOW(VHOST_VIRTIO, 0x07, int)
37 #define VHOST_SET_VRING_NUM _IOW(VHOST_VIRTIO, 0x10, struct vhost_vring_state)
38 #define VHOST_SET_VRING_ADDR _IOW(VHOST_VIRTIO, 0x11, struct vhost_vring_addr)
39 #define VHOST_SET_VRING_BASE _IOW(VHOST_VIRTIO, 0x12, struct vhost_vring_state)
40 #define VHOST_GET_VRING_BASE _IOWR(VHOST_VIRTIO, 0x12, struct vhost_vring_state)
41 #define VHOST_SET_VRING_KICK _IOW(VHOST_VIRTIO, 0x20, struct vhost_vring_file)
42 #define VHOST_SET_VRING_CALL _IOW(VHOST_VIRTIO, 0x21, struct vhost_vring_file)
43 #define VHOST_SET_VRING_ERR _IOW(VHOST_VIRTIO, 0x22, struct vhost_vring_file)
44 #define VHOST_NET_SET_BACKEND _IOW(VHOST_VIRTIO, 0x30, struct vhost_vring_file)
45 
46 /* with below features, vhost kernel does not need to do the checksum and TSO,
47  * these info will be passed to virtio_user through virtio net header.
48  */
49 #define VHOST_KERNEL_GUEST_OFFLOADS_MASK	\
50 	((1ULL << VIRTIO_NET_F_GUEST_CSUM) |	\
51 	 (1ULL << VIRTIO_NET_F_GUEST_TSO4) |	\
52 	 (1ULL << VIRTIO_NET_F_GUEST_TSO6) |	\
53 	 (1ULL << VIRTIO_NET_F_GUEST_ECN)  |	\
54 	 (1ULL << VIRTIO_NET_F_GUEST_UFO))
55 
56 /* with below features, when flows from virtio_user to vhost kernel
57  * (1) if flows goes up through the kernel networking stack, it does not need
58  * to verify checksum, which can save CPU cycles;
59  * (2) if flows goes through a Linux bridge and outside from an interface
60  * (kernel driver), checksum and TSO will be done by GSO in kernel or even
61  * offloaded into real physical device.
62  */
63 #define VHOST_KERNEL_HOST_OFFLOADS_MASK		\
64 	((1ULL << VIRTIO_NET_F_HOST_TSO4) |	\
65 	 (1ULL << VIRTIO_NET_F_HOST_TSO6) |	\
66 	 (1ULL << VIRTIO_NET_F_CSUM))
67 
68 static uint64_t max_regions = 64;
69 
70 static void
71 get_vhost_kernel_max_regions(void)
72 {
73 	int fd;
74 	char buf[20] = {'\0'};
75 
76 	fd = open("/sys/module/vhost/parameters/max_mem_regions", O_RDONLY);
77 	if (fd < 0)
78 		return;
79 
80 	if (read(fd, buf, sizeof(buf) - 1) > 0)
81 		max_regions = strtoull(buf, NULL, 10);
82 
83 	close(fd);
84 }
85 
86 static int
87 vhost_kernel_ioctl(int fd, uint64_t request, void *arg)
88 {
89 	int ret;
90 
91 	ret = ioctl(fd, request, arg);
92 	if (ret) {
93 		PMD_DRV_LOG(ERR, "Vhost-kernel ioctl %"PRIu64" failed (%s)",
94 				request, strerror(errno));
95 		return -1;
96 	}
97 
98 	return 0;
99 }
100 
101 static int
102 vhost_kernel_set_owner(struct virtio_user_dev *dev)
103 {
104 	int ret;
105 	uint32_t i;
106 	struct vhost_kernel_data *data = dev->backend_data;
107 
108 	for (i = 0; i < dev->max_queue_pairs; ++i) {
109 		if (data->vhostfds[i] < 0)
110 			continue;
111 
112 		ret = vhost_kernel_ioctl(data->vhostfds[i], VHOST_SET_OWNER, NULL);
113 		if (ret < 0)
114 			return ret;
115 	}
116 
117 	return 0;
118 }
119 
120 static int
121 vhost_kernel_get_features(struct virtio_user_dev *dev, uint64_t *features)
122 {
123 	int ret;
124 	unsigned int tap_features;
125 	struct vhost_kernel_data *data = dev->backend_data;
126 
127 	ret = vhost_kernel_ioctl(data->vhostfds[0], VHOST_GET_FEATURES, features);
128 	if (ret < 0) {
129 		PMD_DRV_LOG(ERR, "Failed to get features");
130 		return -1;
131 	}
132 
133 	ret = tap_support_features(&tap_features);
134 	if (ret < 0) {
135 		PMD_DRV_LOG(ERR, "Failed to get TAP features");
136 		return -1;
137 	}
138 
139 	/* with tap as the backend, all these features are supported
140 	 * but not claimed by vhost-net, so we add them back when
141 	 * reporting to upper layer.
142 	 */
143 	if (tap_features & IFF_VNET_HDR) {
144 		*features |= VHOST_KERNEL_GUEST_OFFLOADS_MASK;
145 		*features |= VHOST_KERNEL_HOST_OFFLOADS_MASK;
146 	}
147 
148 	/* vhost_kernel will not declare this feature, but it does
149 	 * support multi-queue.
150 	 */
151 	if (tap_features & IFF_MULTI_QUEUE)
152 		*features |= (1ull << VIRTIO_NET_F_MQ);
153 
154 	return 0;
155 }
156 
157 static int
158 vhost_kernel_set_features(struct virtio_user_dev *dev, uint64_t features)
159 {
160 	struct vhost_kernel_data *data = dev->backend_data;
161 	uint32_t i;
162 	int ret;
163 
164 	/* We don't need memory protection here */
165 	features &= ~(1ULL << VIRTIO_F_IOMMU_PLATFORM);
166 	/* VHOST kernel does not know about below flags */
167 	features &= ~VHOST_KERNEL_GUEST_OFFLOADS_MASK;
168 	features &= ~VHOST_KERNEL_HOST_OFFLOADS_MASK;
169 	features &= ~(1ULL << VIRTIO_NET_F_MQ);
170 
171 	for (i = 0; i < dev->max_queue_pairs; ++i) {
172 		if (data->vhostfds[i] < 0)
173 			continue;
174 
175 		ret = vhost_kernel_ioctl(data->vhostfds[i], VHOST_SET_FEATURES, &features);
176 		if (ret < 0)
177 			return ret;
178 	}
179 
180 	return 0;
181 }
182 
183 static int
184 add_memseg_list(const struct rte_memseg_list *msl, void *arg)
185 {
186 	struct vhost_memory_kernel *vm = arg;
187 	struct vhost_memory_region *mr;
188 	void *start_addr;
189 	uint64_t len;
190 
191 	if (msl->external)
192 		return 0;
193 
194 	if (vm->nregions >= max_regions)
195 		return -1;
196 
197 	start_addr = msl->base_va;
198 	len = msl->page_sz * msl->memseg_arr.len;
199 
200 	mr = &vm->regions[vm->nregions++];
201 
202 	mr->guest_phys_addr = (uint64_t)(uintptr_t)start_addr;
203 	mr->userspace_addr = (uint64_t)(uintptr_t)start_addr;
204 	mr->memory_size = len;
205 	mr->mmap_offset = 0; /* flags_padding */
206 
207 	PMD_DRV_LOG(DEBUG, "index=%u addr=%p len=%" PRIu64,
208 			vm->nregions - 1, start_addr, len);
209 
210 	return 0;
211 }
212 
213 /* By default, vhost kernel module allows 64 regions, but DPDK may
214  * have much more memory regions. Below function will treat each
215  * contiguous memory space reserved by DPDK as one region.
216  */
217 static int
218 vhost_kernel_set_memory_table(struct virtio_user_dev *dev)
219 {
220 	uint32_t i;
221 	struct vhost_kernel_data *data = dev->backend_data;
222 	struct vhost_memory_kernel *vm;
223 	int ret;
224 
225 	vm = malloc(sizeof(struct vhost_memory_kernel) +
226 			max_regions *
227 			sizeof(struct vhost_memory_region));
228 	if (!vm)
229 		goto err;
230 
231 	vm->nregions = 0;
232 	vm->padding = 0;
233 
234 	/*
235 	 * The memory lock has already been taken by memory subsystem
236 	 * or virtio_user_start_device().
237 	 */
238 	ret = rte_memseg_list_walk_thread_unsafe(add_memseg_list, vm);
239 	if (ret < 0)
240 		goto err_free;
241 
242 	for (i = 0; i < dev->max_queue_pairs; ++i) {
243 		if (data->vhostfds[i] < 0)
244 			continue;
245 
246 		ret = vhost_kernel_ioctl(data->vhostfds[i], VHOST_SET_MEM_TABLE, vm);
247 		if (ret < 0)
248 			goto err_free;
249 	}
250 
251 	free(vm);
252 
253 	return 0;
254 err_free:
255 	free(vm);
256 err:
257 	PMD_DRV_LOG(ERR, "Failed to set memory table");
258 	return -1;
259 }
260 
261 static int
262 vhost_kernel_set_vring(struct virtio_user_dev *dev, uint64_t req, struct vhost_vring_state *state)
263 {
264 	int ret, fd;
265 	unsigned int index = state->index;
266 	struct vhost_kernel_data *data = dev->backend_data;
267 
268 	/* Convert from queue index to queue-pair & offset */
269 	fd = data->vhostfds[state->index / 2];
270 	state->index %= 2;
271 
272 	ret = vhost_kernel_ioctl(fd, req, state);
273 	if (ret < 0) {
274 		PMD_DRV_LOG(ERR, "Failed to set vring (request %" PRIu64 ")", req);
275 		return -1;
276 	}
277 
278 	/* restore index back to queue index */
279 	state->index = index;
280 
281 	return 0;
282 }
283 
284 static int
285 vhost_kernel_set_vring_num(struct virtio_user_dev *dev, struct vhost_vring_state *state)
286 {
287 	return vhost_kernel_set_vring(dev, VHOST_SET_VRING_NUM, state);
288 }
289 
290 static int
291 vhost_kernel_set_vring_base(struct virtio_user_dev *dev, struct vhost_vring_state *state)
292 {
293 	return vhost_kernel_set_vring(dev, VHOST_SET_VRING_BASE, state);
294 }
295 
296 static int
297 vhost_kernel_get_vring_base(struct virtio_user_dev *dev, struct vhost_vring_state *state)
298 {
299 	return vhost_kernel_set_vring(dev, VHOST_GET_VRING_BASE, state);
300 }
301 
302 static int
303 vhost_kernel_set_vring_file(struct virtio_user_dev *dev, uint64_t req,
304 		struct vhost_vring_file *file)
305 {
306 	int ret, fd;
307 	unsigned int index = file->index;
308 	struct vhost_kernel_data *data = dev->backend_data;
309 
310 	/* Convert from queue index to queue-pair & offset */
311 	fd = data->vhostfds[file->index / 2];
312 	file->index %= 2;
313 
314 	ret = vhost_kernel_ioctl(fd, req, file);
315 	if (ret < 0) {
316 		PMD_DRV_LOG(ERR, "Failed to set vring file (request %" PRIu64 ")", req);
317 		return -1;
318 	}
319 
320 	/* restore index back to queue index */
321 	file->index = index;
322 
323 	return 0;
324 }
325 
326 static int
327 vhost_kernel_set_vring_kick(struct virtio_user_dev *dev, struct vhost_vring_file *file)
328 {
329 	return vhost_kernel_set_vring_file(dev, VHOST_SET_VRING_KICK, file);
330 }
331 
332 static int
333 vhost_kernel_set_vring_call(struct virtio_user_dev *dev, struct vhost_vring_file *file)
334 {
335 	return vhost_kernel_set_vring_file(dev, VHOST_SET_VRING_CALL, file);
336 }
337 
338 static int
339 vhost_kernel_set_vring_addr(struct virtio_user_dev *dev, struct vhost_vring_addr *addr)
340 {
341 	int ret, fd;
342 	unsigned int index = addr->index;
343 	struct vhost_kernel_data *data = dev->backend_data;
344 
345 	/* Convert from queue index to queue-pair & offset */
346 	fd = data->vhostfds[addr->index / 2];
347 	addr->index %= 2;
348 
349 	ret = vhost_kernel_ioctl(fd, VHOST_SET_VRING_ADDR, addr);
350 	if (ret < 0) {
351 		PMD_DRV_LOG(ERR, "Failed to set vring address");
352 		return -1;
353 	}
354 
355 	/* restore index back to queue index */
356 	addr->index = index;
357 
358 	return 0;
359 }
360 
361 static int
362 vhost_kernel_get_status(struct virtio_user_dev *dev __rte_unused, uint8_t *status __rte_unused)
363 {
364 	return -ENOTSUP;
365 }
366 
367 static int
368 vhost_kernel_set_status(struct virtio_user_dev *dev __rte_unused, uint8_t status __rte_unused)
369 {
370 	return -ENOTSUP;
371 }
372 
373 /**
374  * Set up environment to talk with a vhost kernel backend.
375  *
376  * @return
377  *   - (-1) if fail to set up;
378  *   - (>=0) if successful.
379  */
380 static int
381 vhost_kernel_setup(struct virtio_user_dev *dev)
382 {
383 	int vhostfd;
384 	uint32_t q, i;
385 	struct vhost_kernel_data *data;
386 
387 	data = malloc(sizeof(*data));
388 	if (!data) {
389 		PMD_INIT_LOG(ERR, "(%s) Failed to allocate Vhost-kernel data", dev->path);
390 		return -1;
391 	}
392 
393 	data->vhostfds = malloc(dev->max_queue_pairs * sizeof(int));
394 	if (!data->vhostfds) {
395 		PMD_INIT_LOG(ERR, "(%s) Failed to allocate Vhost FDs", dev->path);
396 		goto err_data;
397 	}
398 	data->tapfds = malloc(dev->max_queue_pairs * sizeof(int));
399 	if (!data->tapfds) {
400 		PMD_INIT_LOG(ERR, "(%s) Failed to allocate TAP FDs", dev->path);
401 		goto err_vhostfds;
402 	}
403 
404 	for (q = 0; q < dev->max_queue_pairs; ++q) {
405 		data->vhostfds[q] = -1;
406 		data->tapfds[q] = -1;
407 	}
408 
409 	get_vhost_kernel_max_regions();
410 
411 	for (i = 0; i < dev->max_queue_pairs; ++i) {
412 		vhostfd = open(dev->path, O_RDWR);
413 		if (vhostfd < 0) {
414 			PMD_DRV_LOG(ERR, "fail to open %s, %s", dev->path, strerror(errno));
415 			goto err_tapfds;
416 		}
417 
418 		data->vhostfds[i] = vhostfd;
419 	}
420 
421 	dev->backend_data = data;
422 
423 	return 0;
424 
425 err_tapfds:
426 	for (i = 0; i < dev->max_queue_pairs; i++)
427 		if (data->vhostfds[i] >= 0)
428 			close(data->vhostfds[i]);
429 
430 	free(data->tapfds);
431 err_vhostfds:
432 	free(data->vhostfds);
433 err_data:
434 	free(data);
435 
436 	return -1;
437 }
438 
439 static int
440 vhost_kernel_destroy(struct virtio_user_dev *dev)
441 {
442 	struct vhost_kernel_data *data = dev->backend_data;
443 	uint32_t i;
444 
445 	if (!data)
446 		return 0;
447 
448 	for (i = 0; i < dev->max_queue_pairs; ++i) {
449 		if (data->vhostfds[i] >= 0)
450 			close(data->vhostfds[i]);
451 		if (data->tapfds[i] >= 0)
452 			close(data->tapfds[i]);
453 	}
454 
455 	free(data->vhostfds);
456 	free(data->tapfds);
457 	free(data);
458 	dev->backend_data = NULL;
459 
460 	return 0;
461 }
462 
463 static int
464 vhost_kernel_set_backend(int vhostfd, int tapfd)
465 {
466 	struct vhost_vring_file f;
467 
468 	f.fd = tapfd;
469 	f.index = 0;
470 	if (ioctl(vhostfd, VHOST_NET_SET_BACKEND, &f) < 0) {
471 		PMD_DRV_LOG(ERR, "VHOST_NET_SET_BACKEND fails, %s",
472 				strerror(errno));
473 		return -1;
474 	}
475 
476 	f.index = 1;
477 	if (ioctl(vhostfd, VHOST_NET_SET_BACKEND, &f) < 0) {
478 		PMD_DRV_LOG(ERR, "VHOST_NET_SET_BACKEND fails, %s",
479 				strerror(errno));
480 		return -1;
481 	}
482 
483 	return 0;
484 }
485 
486 static int
487 vhost_kernel_enable_queue_pair(struct virtio_user_dev *dev,
488 			       uint16_t pair_idx,
489 			       int enable)
490 {
491 	int hdr_size;
492 	int vhostfd;
493 	int tapfd;
494 	int req_mq = (dev->max_queue_pairs > 1);
495 	struct vhost_kernel_data *data = dev->backend_data;
496 
497 	vhostfd = data->vhostfds[pair_idx];
498 
499 	if (dev->qp_enabled[pair_idx] == enable)
500 		return 0;
501 
502 	if (!enable) {
503 		tapfd = data->tapfds[pair_idx];
504 		if (vhost_kernel_set_backend(vhostfd, -1) < 0) {
505 			PMD_DRV_LOG(ERR, "fail to set backend for vhost kernel");
506 			return -1;
507 		}
508 		if (req_mq && vhost_kernel_tap_set_queue(tapfd, false) < 0) {
509 			PMD_DRV_LOG(ERR, "fail to disable tap for vhost kernel");
510 			return -1;
511 		}
512 		dev->qp_enabled[pair_idx] = false;
513 		return 0;
514 	}
515 
516 	if (data->tapfds[pair_idx] >= 0) {
517 		tapfd = data->tapfds[pair_idx];
518 		if (vhost_kernel_tap_set_offload(tapfd, dev->features) == -1)
519 			return -1;
520 		if (req_mq && vhost_kernel_tap_set_queue(tapfd, true) < 0) {
521 			PMD_DRV_LOG(ERR, "fail to enable tap for vhost kernel");
522 			return -1;
523 		}
524 		goto set_backend;
525 	}
526 
527 	if ((dev->features & (1ULL << VIRTIO_NET_F_MRG_RXBUF)) ||
528 	    (dev->features & (1ULL << VIRTIO_F_VERSION_1)))
529 		hdr_size = sizeof(struct virtio_net_hdr_mrg_rxbuf);
530 	else
531 		hdr_size = sizeof(struct virtio_net_hdr);
532 
533 	tapfd = vhost_kernel_open_tap(&dev->ifname, hdr_size, req_mq,
534 			 (char *)dev->mac_addr, dev->features);
535 	if (tapfd < 0) {
536 		PMD_DRV_LOG(ERR, "fail to open tap for vhost kernel");
537 		return -1;
538 	}
539 
540 	data->tapfds[pair_idx] = tapfd;
541 
542 set_backend:
543 	if (vhost_kernel_set_backend(vhostfd, tapfd) < 0) {
544 		PMD_DRV_LOG(ERR, "fail to set backend for vhost kernel");
545 		return -1;
546 	}
547 
548 	dev->qp_enabled[pair_idx] = true;
549 	return 0;
550 }
551 
552 static int
553 vhost_kernel_get_backend_features(uint64_t *features)
554 {
555 	*features = 0;
556 
557 	return 0;
558 }
559 
560 static int
561 vhost_kernel_update_link_state(struct virtio_user_dev *dev __rte_unused)
562 {
563 	/* Nothing to update (Maybe get TAP interface link state?) */
564 	return 0;
565 }
566 
567 static int
568 vhost_kernel_get_intr_fd(struct virtio_user_dev *dev __rte_unused)
569 {
570 	/* No link state interrupt with Vhost-kernel */
571 	return -1;
572 }
573 
574 struct virtio_user_backend_ops virtio_ops_kernel = {
575 	.setup = vhost_kernel_setup,
576 	.destroy = vhost_kernel_destroy,
577 	.get_backend_features = vhost_kernel_get_backend_features,
578 	.set_owner = vhost_kernel_set_owner,
579 	.get_features = vhost_kernel_get_features,
580 	.set_features = vhost_kernel_set_features,
581 	.set_memory_table = vhost_kernel_set_memory_table,
582 	.set_vring_num = vhost_kernel_set_vring_num,
583 	.set_vring_base = vhost_kernel_set_vring_base,
584 	.get_vring_base = vhost_kernel_get_vring_base,
585 	.set_vring_call = vhost_kernel_set_vring_call,
586 	.set_vring_kick = vhost_kernel_set_vring_kick,
587 	.set_vring_addr = vhost_kernel_set_vring_addr,
588 	.get_status = vhost_kernel_get_status,
589 	.set_status = vhost_kernel_set_status,
590 	.enable_qp = vhost_kernel_enable_queue_pair,
591 	.update_link_state = vhost_kernel_update_link_state,
592 	.get_intr_fd = vhost_kernel_get_intr_fd,
593 };
594