xref: /dpdk/drivers/net/virtio/virtio_user/vhost_kernel.c (revision 68a03efeed657e6e05f281479b33b51102797e15)
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 	struct vhost_kernel_data *data = dev->backend_data;
105 
106 	return vhost_kernel_ioctl(data->vhostfds[0], VHOST_SET_OWNER, NULL);
107 }
108 
109 static int
110 vhost_kernel_get_features(struct virtio_user_dev *dev, uint64_t *features)
111 {
112 	int ret;
113 	unsigned int tap_features;
114 	struct vhost_kernel_data *data = dev->backend_data;
115 
116 	ret = vhost_kernel_ioctl(data->vhostfds[0], VHOST_GET_FEATURES, features);
117 	if (ret < 0) {
118 		PMD_DRV_LOG(ERR, "Failed to get features");
119 		return -1;
120 	}
121 
122 	ret = tap_support_features(&tap_features);
123 	if (ret < 0) {
124 		PMD_DRV_LOG(ERR, "Failed to get TAP features");
125 		return -1;
126 	}
127 
128 	/* with tap as the backend, all these features are supported
129 	 * but not claimed by vhost-net, so we add them back when
130 	 * reporting to upper layer.
131 	 */
132 	if (tap_features & IFF_VNET_HDR) {
133 		*features |= VHOST_KERNEL_GUEST_OFFLOADS_MASK;
134 		*features |= VHOST_KERNEL_HOST_OFFLOADS_MASK;
135 	}
136 
137 	/* vhost_kernel will not declare this feature, but it does
138 	 * support multi-queue.
139 	 */
140 	if (tap_features & IFF_MULTI_QUEUE)
141 		*features |= (1ull << VIRTIO_NET_F_MQ);
142 
143 	return 0;
144 }
145 
146 static int
147 vhost_kernel_set_features(struct virtio_user_dev *dev, uint64_t features)
148 {
149 	struct vhost_kernel_data *data = dev->backend_data;
150 
151 	/* We don't need memory protection here */
152 	features &= ~(1ULL << VIRTIO_F_IOMMU_PLATFORM);
153 	/* VHOST kernel does not know about below flags */
154 	features &= ~VHOST_KERNEL_GUEST_OFFLOADS_MASK;
155 	features &= ~VHOST_KERNEL_HOST_OFFLOADS_MASK;
156 	features &= ~(1ULL << VIRTIO_NET_F_MQ);
157 
158 	return vhost_kernel_ioctl(data->vhostfds[0], VHOST_SET_FEATURES, &features);
159 }
160 
161 static int
162 add_memseg_list(const struct rte_memseg_list *msl, void *arg)
163 {
164 	struct vhost_memory_kernel *vm = arg;
165 	struct vhost_memory_region *mr;
166 	void *start_addr;
167 	uint64_t len;
168 
169 	if (msl->external)
170 		return 0;
171 
172 	if (vm->nregions >= max_regions)
173 		return -1;
174 
175 	start_addr = msl->base_va;
176 	len = msl->page_sz * msl->memseg_arr.len;
177 
178 	mr = &vm->regions[vm->nregions++];
179 
180 	mr->guest_phys_addr = (uint64_t)(uintptr_t)start_addr;
181 	mr->userspace_addr = (uint64_t)(uintptr_t)start_addr;
182 	mr->memory_size = len;
183 	mr->mmap_offset = 0; /* flags_padding */
184 
185 	PMD_DRV_LOG(DEBUG, "index=%u addr=%p len=%" PRIu64,
186 			vm->nregions - 1, start_addr, len);
187 
188 	return 0;
189 }
190 
191 /* By default, vhost kernel module allows 64 regions, but DPDK may
192  * have much more memory regions. Below function will treat each
193  * contiguous memory space reserved by DPDK as one region.
194  */
195 static int
196 vhost_kernel_set_memory_table(struct virtio_user_dev *dev)
197 {
198 	struct vhost_kernel_data *data = dev->backend_data;
199 	struct vhost_memory_kernel *vm;
200 	int ret;
201 
202 	vm = malloc(sizeof(struct vhost_memory_kernel) +
203 			max_regions *
204 			sizeof(struct vhost_memory_region));
205 	if (!vm)
206 		goto err;
207 
208 	vm->nregions = 0;
209 	vm->padding = 0;
210 
211 	/*
212 	 * The memory lock has already been taken by memory subsystem
213 	 * or virtio_user_start_device().
214 	 */
215 	ret = rte_memseg_list_walk_thread_unsafe(add_memseg_list, vm);
216 	if (ret < 0)
217 		goto err_free;
218 
219 	ret = vhost_kernel_ioctl(data->vhostfds[0], VHOST_SET_MEM_TABLE, vm);
220 	if (ret < 0)
221 		goto err_free;
222 
223 	free(vm);
224 
225 	return 0;
226 err_free:
227 	free(vm);
228 err:
229 	PMD_DRV_LOG(ERR, "Failed to set memory table");
230 	return -1;
231 }
232 
233 static int
234 vhost_kernel_set_vring(struct virtio_user_dev *dev, uint64_t req, struct vhost_vring_state *state)
235 {
236 	int ret, fd;
237 	unsigned int index = state->index;
238 	struct vhost_kernel_data *data = dev->backend_data;
239 
240 	/* Convert from queue index to queue-pair & offset */
241 	fd = data->vhostfds[state->index / 2];
242 	state->index %= 2;
243 
244 	ret = vhost_kernel_ioctl(fd, req, state);
245 	if (ret < 0) {
246 		PMD_DRV_LOG(ERR, "Failed to set vring (request %" PRIu64 ")", req);
247 		return -1;
248 	}
249 
250 	/* restore index back to queue index */
251 	state->index = index;
252 
253 	return 0;
254 }
255 
256 static int
257 vhost_kernel_set_vring_num(struct virtio_user_dev *dev, struct vhost_vring_state *state)
258 {
259 	return vhost_kernel_set_vring(dev, VHOST_SET_VRING_NUM, state);
260 }
261 
262 static int
263 vhost_kernel_set_vring_base(struct virtio_user_dev *dev, struct vhost_vring_state *state)
264 {
265 	return vhost_kernel_set_vring(dev, VHOST_SET_VRING_BASE, state);
266 }
267 
268 static int
269 vhost_kernel_get_vring_base(struct virtio_user_dev *dev, struct vhost_vring_state *state)
270 {
271 	return vhost_kernel_set_vring(dev, VHOST_GET_VRING_BASE, state);
272 }
273 
274 static int
275 vhost_kernel_set_vring_file(struct virtio_user_dev *dev, uint64_t req,
276 		struct vhost_vring_file *file)
277 {
278 	int ret, fd;
279 	unsigned int index = file->index;
280 	struct vhost_kernel_data *data = dev->backend_data;
281 
282 	/* Convert from queue index to queue-pair & offset */
283 	fd = data->vhostfds[file->index / 2];
284 	file->index %= 2;
285 
286 	ret = vhost_kernel_ioctl(fd, req, file);
287 	if (ret < 0) {
288 		PMD_DRV_LOG(ERR, "Failed to set vring file (request %" PRIu64 ")", req);
289 		return -1;
290 	}
291 
292 	/* restore index back to queue index */
293 	file->index = index;
294 
295 	return 0;
296 }
297 
298 static int
299 vhost_kernel_set_vring_kick(struct virtio_user_dev *dev, struct vhost_vring_file *file)
300 {
301 	return vhost_kernel_set_vring_file(dev, VHOST_SET_VRING_KICK, file);
302 }
303 
304 static int
305 vhost_kernel_set_vring_call(struct virtio_user_dev *dev, struct vhost_vring_file *file)
306 {
307 	return vhost_kernel_set_vring_file(dev, VHOST_SET_VRING_CALL, file);
308 }
309 
310 static int
311 vhost_kernel_set_vring_addr(struct virtio_user_dev *dev, struct vhost_vring_addr *addr)
312 {
313 	int ret, fd;
314 	unsigned int index = addr->index;
315 	struct vhost_kernel_data *data = dev->backend_data;
316 
317 	/* Convert from queue index to queue-pair & offset */
318 	fd = data->vhostfds[addr->index / 2];
319 	addr->index %= 2;
320 
321 	ret = vhost_kernel_ioctl(fd, VHOST_SET_VRING_ADDR, addr);
322 	if (ret < 0) {
323 		PMD_DRV_LOG(ERR, "Failed to set vring address");
324 		return -1;
325 	}
326 
327 	/* restore index back to queue index */
328 	addr->index = index;
329 
330 	return 0;
331 }
332 
333 static int
334 vhost_kernel_get_status(struct virtio_user_dev *dev __rte_unused, uint8_t *status __rte_unused)
335 {
336 	return -ENOTSUP;
337 }
338 
339 static int
340 vhost_kernel_set_status(struct virtio_user_dev *dev __rte_unused, uint8_t status __rte_unused)
341 {
342 	return -ENOTSUP;
343 }
344 
345 /**
346  * Set up environment to talk with a vhost kernel backend.
347  *
348  * @return
349  *   - (-1) if fail to set up;
350  *   - (>=0) if successful.
351  */
352 static int
353 vhost_kernel_setup(struct virtio_user_dev *dev)
354 {
355 	int vhostfd;
356 	uint32_t q, i;
357 	struct vhost_kernel_data *data;
358 
359 	data = malloc(sizeof(*data));
360 	if (!data) {
361 		PMD_INIT_LOG(ERR, "(%s) Failed to allocate Vhost-kernel data", dev->path);
362 		return -1;
363 	}
364 
365 	data->vhostfds = malloc(dev->max_queue_pairs * sizeof(int));
366 	if (!data->vhostfds) {
367 		PMD_INIT_LOG(ERR, "(%s) Failed to allocate Vhost FDs", dev->path);
368 		goto err_data;
369 	}
370 	data->tapfds = malloc(dev->max_queue_pairs * sizeof(int));
371 	if (!data->tapfds) {
372 		PMD_INIT_LOG(ERR, "(%s) Failed to allocate TAP FDs", dev->path);
373 		goto err_vhostfds;
374 	}
375 
376 	for (q = 0; q < dev->max_queue_pairs; ++q) {
377 		data->vhostfds[q] = -1;
378 		data->tapfds[q] = -1;
379 	}
380 
381 	get_vhost_kernel_max_regions();
382 
383 	for (i = 0; i < dev->max_queue_pairs; ++i) {
384 		vhostfd = open(dev->path, O_RDWR);
385 		if (vhostfd < 0) {
386 			PMD_DRV_LOG(ERR, "fail to open %s, %s", dev->path, strerror(errno));
387 			goto err_tapfds;
388 		}
389 
390 		data->vhostfds[i] = vhostfd;
391 	}
392 
393 	dev->backend_data = data;
394 
395 	return 0;
396 
397 err_tapfds:
398 	for (i = 0; i < dev->max_queue_pairs; i++)
399 		if (data->vhostfds[i] >= 0)
400 			close(data->vhostfds[i]);
401 
402 	free(data->tapfds);
403 err_vhostfds:
404 	free(data->vhostfds);
405 err_data:
406 	free(data);
407 
408 	return -1;
409 }
410 
411 static int
412 vhost_kernel_destroy(struct virtio_user_dev *dev)
413 {
414 	struct vhost_kernel_data *data = dev->backend_data;
415 	uint32_t i;
416 
417 	if (!data)
418 		return 0;
419 
420 	for (i = 0; i < dev->max_queue_pairs; ++i) {
421 		if (data->vhostfds[i] >= 0)
422 			close(data->vhostfds[i]);
423 		if (data->tapfds[i] >= 0)
424 			close(data->tapfds[i]);
425 	}
426 
427 	free(data->vhostfds);
428 	free(data->tapfds);
429 	free(data);
430 	dev->backend_data = NULL;
431 
432 	return 0;
433 }
434 
435 static int
436 vhost_kernel_set_backend(int vhostfd, int tapfd)
437 {
438 	struct vhost_vring_file f;
439 
440 	f.fd = tapfd;
441 	f.index = 0;
442 	if (ioctl(vhostfd, VHOST_NET_SET_BACKEND, &f) < 0) {
443 		PMD_DRV_LOG(ERR, "VHOST_NET_SET_BACKEND fails, %s",
444 				strerror(errno));
445 		return -1;
446 	}
447 
448 	f.index = 1;
449 	if (ioctl(vhostfd, VHOST_NET_SET_BACKEND, &f) < 0) {
450 		PMD_DRV_LOG(ERR, "VHOST_NET_SET_BACKEND fails, %s",
451 				strerror(errno));
452 		return -1;
453 	}
454 
455 	return 0;
456 }
457 
458 static int
459 vhost_kernel_enable_queue_pair(struct virtio_user_dev *dev,
460 			       uint16_t pair_idx,
461 			       int enable)
462 {
463 	int hdr_size;
464 	int vhostfd;
465 	int tapfd;
466 	int req_mq = (dev->max_queue_pairs > 1);
467 	struct vhost_kernel_data *data = dev->backend_data;
468 
469 	vhostfd = data->vhostfds[pair_idx];
470 
471 	if (dev->qp_enabled[pair_idx] == enable)
472 		return 0;
473 
474 	if (!enable) {
475 		tapfd = data->tapfds[pair_idx];
476 		if (vhost_kernel_set_backend(vhostfd, -1) < 0) {
477 			PMD_DRV_LOG(ERR, "fail to set backend for vhost kernel");
478 			return -1;
479 		}
480 		if (req_mq && vhost_kernel_tap_set_queue(tapfd, false) < 0) {
481 			PMD_DRV_LOG(ERR, "fail to disable tap for vhost kernel");
482 			return -1;
483 		}
484 		dev->qp_enabled[pair_idx] = false;
485 		return 0;
486 	}
487 
488 	if (data->tapfds[pair_idx] >= 0) {
489 		tapfd = data->tapfds[pair_idx];
490 		if (vhost_kernel_tap_set_offload(tapfd, dev->features) == -1)
491 			return -1;
492 		if (req_mq && vhost_kernel_tap_set_queue(tapfd, true) < 0) {
493 			PMD_DRV_LOG(ERR, "fail to enable tap for vhost kernel");
494 			return -1;
495 		}
496 		goto set_backend;
497 	}
498 
499 	if ((dev->features & (1ULL << VIRTIO_NET_F_MRG_RXBUF)) ||
500 	    (dev->features & (1ULL << VIRTIO_F_VERSION_1)))
501 		hdr_size = sizeof(struct virtio_net_hdr_mrg_rxbuf);
502 	else
503 		hdr_size = sizeof(struct virtio_net_hdr);
504 
505 	tapfd = vhost_kernel_open_tap(&dev->ifname, hdr_size, req_mq,
506 			 (char *)dev->mac_addr, dev->features);
507 	if (tapfd < 0) {
508 		PMD_DRV_LOG(ERR, "fail to open tap for vhost kernel");
509 		return -1;
510 	}
511 
512 	data->tapfds[pair_idx] = tapfd;
513 
514 set_backend:
515 	if (vhost_kernel_set_backend(vhostfd, tapfd) < 0) {
516 		PMD_DRV_LOG(ERR, "fail to set backend for vhost kernel");
517 		return -1;
518 	}
519 
520 	dev->qp_enabled[pair_idx] = true;
521 	return 0;
522 }
523 
524 static int
525 vhost_kernel_get_backend_features(uint64_t *features)
526 {
527 	*features = 0;
528 
529 	return 0;
530 }
531 
532 static int
533 vhost_kernel_update_link_state(struct virtio_user_dev *dev __rte_unused)
534 {
535 	/* Nothing to update (Maybe get TAP interface link state?) */
536 	return 0;
537 }
538 
539 static int
540 vhost_kernel_get_intr_fd(struct virtio_user_dev *dev __rte_unused)
541 {
542 	/* No link state interrupt with Vhost-kernel */
543 	return -1;
544 }
545 
546 struct virtio_user_backend_ops virtio_ops_kernel = {
547 	.setup = vhost_kernel_setup,
548 	.destroy = vhost_kernel_destroy,
549 	.get_backend_features = vhost_kernel_get_backend_features,
550 	.set_owner = vhost_kernel_set_owner,
551 	.get_features = vhost_kernel_get_features,
552 	.set_features = vhost_kernel_set_features,
553 	.set_memory_table = vhost_kernel_set_memory_table,
554 	.set_vring_num = vhost_kernel_set_vring_num,
555 	.set_vring_base = vhost_kernel_set_vring_base,
556 	.get_vring_base = vhost_kernel_get_vring_base,
557 	.set_vring_call = vhost_kernel_set_vring_call,
558 	.set_vring_kick = vhost_kernel_set_vring_kick,
559 	.set_vring_addr = vhost_kernel_set_vring_addr,
560 	.get_status = vhost_kernel_get_status,
561 	.set_status = vhost_kernel_set_status,
562 	.enable_qp = vhost_kernel_enable_queue_pair,
563 	.update_link_state = vhost_kernel_update_link_state,
564 	.get_intr_fd = vhost_kernel_get_intr_fd,
565 };
566