xref: /openbmc/linux/drivers/vhost/vdpa.c (revision 9009b455811b0fa1f6b0adfa94db136984db5a38) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2018-2020 Intel Corporation.
4  * Copyright (C) 2020 Red Hat, Inc.
5  *
6  * Author: Tiwei Bie <tiwei.bie@intel.com>
7  *         Jason Wang <jasowang@redhat.com>
8  *
9  * Thanks Michael S. Tsirkin for the valuable comments and
10  * suggestions.  And thanks to Cunming Liang and Zhihong Wang for all
11  * their supports.
12  */
13 
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/cdev.h>
17 #include <linux/device.h>
18 #include <linux/mm.h>
19 #include <linux/iommu.h>
20 #include <linux/uuid.h>
21 #include <linux/vdpa.h>
22 #include <linux/nospec.h>
23 #include <linux/vhost.h>
24 #include <linux/virtio_net.h>
25 
26 #include "vhost.h"
27 
28 enum {
29 	VHOST_VDPA_BACKEND_FEATURES =
30 	(1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2) |
31 	(1ULL << VHOST_BACKEND_F_IOTLB_BATCH),
32 };
33 
34 #define VHOST_VDPA_DEV_MAX (1U << MINORBITS)
35 
36 struct vhost_vdpa {
37 	struct vhost_dev vdev;
38 	struct iommu_domain *domain;
39 	struct vhost_virtqueue *vqs;
40 	struct completion completion;
41 	struct vdpa_device *vdpa;
42 	struct device dev;
43 	struct cdev cdev;
44 	atomic_t opened;
45 	int nvqs;
46 	int virtio_id;
47 	int minor;
48 	struct eventfd_ctx *config_ctx;
49 	int in_batch;
50 	struct vdpa_iova_range range;
51 };
52 
53 static DEFINE_IDA(vhost_vdpa_ida);
54 
55 static dev_t vhost_vdpa_major;
56 
57 static void handle_vq_kick(struct vhost_work *work)
58 {
59 	struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
60 						  poll.work);
61 	struct vhost_vdpa *v = container_of(vq->dev, struct vhost_vdpa, vdev);
62 	const struct vdpa_config_ops *ops = v->vdpa->config;
63 
64 	ops->kick_vq(v->vdpa, vq - v->vqs);
65 }
66 
67 static irqreturn_t vhost_vdpa_virtqueue_cb(void *private)
68 {
69 	struct vhost_virtqueue *vq = private;
70 	struct eventfd_ctx *call_ctx = vq->call_ctx.ctx;
71 
72 	if (call_ctx)
73 		eventfd_signal(call_ctx, 1);
74 
75 	return IRQ_HANDLED;
76 }
77 
78 static irqreturn_t vhost_vdpa_config_cb(void *private)
79 {
80 	struct vhost_vdpa *v = private;
81 	struct eventfd_ctx *config_ctx = v->config_ctx;
82 
83 	if (config_ctx)
84 		eventfd_signal(config_ctx, 1);
85 
86 	return IRQ_HANDLED;
87 }
88 
89 static void vhost_vdpa_setup_vq_irq(struct vhost_vdpa *v, u16 qid)
90 {
91 	struct vhost_virtqueue *vq = &v->vqs[qid];
92 	const struct vdpa_config_ops *ops = v->vdpa->config;
93 	struct vdpa_device *vdpa = v->vdpa;
94 	int ret, irq;
95 
96 	if (!ops->get_vq_irq)
97 		return;
98 
99 	irq = ops->get_vq_irq(vdpa, qid);
100 	irq_bypass_unregister_producer(&vq->call_ctx.producer);
101 	if (!vq->call_ctx.ctx || irq < 0)
102 		return;
103 
104 	vq->call_ctx.producer.token = vq->call_ctx.ctx;
105 	vq->call_ctx.producer.irq = irq;
106 	ret = irq_bypass_register_producer(&vq->call_ctx.producer);
107 	if (unlikely(ret))
108 		dev_info(&v->dev, "vq %u, irq bypass producer (token %p) registration fails, ret =  %d\n",
109 			 qid, vq->call_ctx.producer.token, ret);
110 }
111 
112 static void vhost_vdpa_unsetup_vq_irq(struct vhost_vdpa *v, u16 qid)
113 {
114 	struct vhost_virtqueue *vq = &v->vqs[qid];
115 
116 	irq_bypass_unregister_producer(&vq->call_ctx.producer);
117 }
118 
119 static void vhost_vdpa_reset(struct vhost_vdpa *v)
120 {
121 	struct vdpa_device *vdpa = v->vdpa;
122 
123 	vdpa_reset(vdpa);
124 	v->in_batch = 0;
125 }
126 
127 static long vhost_vdpa_get_device_id(struct vhost_vdpa *v, u8 __user *argp)
128 {
129 	struct vdpa_device *vdpa = v->vdpa;
130 	const struct vdpa_config_ops *ops = vdpa->config;
131 	u32 device_id;
132 
133 	device_id = ops->get_device_id(vdpa);
134 
135 	if (copy_to_user(argp, &device_id, sizeof(device_id)))
136 		return -EFAULT;
137 
138 	return 0;
139 }
140 
141 static long vhost_vdpa_get_status(struct vhost_vdpa *v, u8 __user *statusp)
142 {
143 	struct vdpa_device *vdpa = v->vdpa;
144 	const struct vdpa_config_ops *ops = vdpa->config;
145 	u8 status;
146 
147 	status = ops->get_status(vdpa);
148 
149 	if (copy_to_user(statusp, &status, sizeof(status)))
150 		return -EFAULT;
151 
152 	return 0;
153 }
154 
155 static long vhost_vdpa_set_status(struct vhost_vdpa *v, u8 __user *statusp)
156 {
157 	struct vdpa_device *vdpa = v->vdpa;
158 	const struct vdpa_config_ops *ops = vdpa->config;
159 	u8 status, status_old;
160 	int nvqs = v->nvqs;
161 	u16 i;
162 
163 	if (copy_from_user(&status, statusp, sizeof(status)))
164 		return -EFAULT;
165 
166 	status_old = ops->get_status(vdpa);
167 
168 	/*
169 	 * Userspace shouldn't remove status bits unless reset the
170 	 * status to 0.
171 	 */
172 	if (status != 0 && (ops->get_status(vdpa) & ~status) != 0)
173 		return -EINVAL;
174 
175 	ops->set_status(vdpa, status);
176 
177 	if ((status & VIRTIO_CONFIG_S_DRIVER_OK) && !(status_old & VIRTIO_CONFIG_S_DRIVER_OK))
178 		for (i = 0; i < nvqs; i++)
179 			vhost_vdpa_setup_vq_irq(v, i);
180 
181 	if ((status_old & VIRTIO_CONFIG_S_DRIVER_OK) && !(status & VIRTIO_CONFIG_S_DRIVER_OK))
182 		for (i = 0; i < nvqs; i++)
183 			vhost_vdpa_unsetup_vq_irq(v, i);
184 
185 	return 0;
186 }
187 
188 static int vhost_vdpa_config_validate(struct vhost_vdpa *v,
189 				      struct vhost_vdpa_config *c)
190 {
191 	long size = 0;
192 
193 	switch (v->virtio_id) {
194 	case VIRTIO_ID_NET:
195 		size = sizeof(struct virtio_net_config);
196 		break;
197 	}
198 
199 	if (c->len == 0)
200 		return -EINVAL;
201 
202 	if (c->len > size - c->off)
203 		return -E2BIG;
204 
205 	return 0;
206 }
207 
208 static long vhost_vdpa_get_config(struct vhost_vdpa *v,
209 				  struct vhost_vdpa_config __user *c)
210 {
211 	struct vdpa_device *vdpa = v->vdpa;
212 	struct vhost_vdpa_config config;
213 	unsigned long size = offsetof(struct vhost_vdpa_config, buf);
214 	u8 *buf;
215 
216 	if (copy_from_user(&config, c, size))
217 		return -EFAULT;
218 	if (vhost_vdpa_config_validate(v, &config))
219 		return -EINVAL;
220 	buf = kvzalloc(config.len, GFP_KERNEL);
221 	if (!buf)
222 		return -ENOMEM;
223 
224 	vdpa_get_config(vdpa, config.off, buf, config.len);
225 
226 	if (copy_to_user(c->buf, buf, config.len)) {
227 		kvfree(buf);
228 		return -EFAULT;
229 	}
230 
231 	kvfree(buf);
232 	return 0;
233 }
234 
235 static long vhost_vdpa_set_config(struct vhost_vdpa *v,
236 				  struct vhost_vdpa_config __user *c)
237 {
238 	struct vdpa_device *vdpa = v->vdpa;
239 	const struct vdpa_config_ops *ops = vdpa->config;
240 	struct vhost_vdpa_config config;
241 	unsigned long size = offsetof(struct vhost_vdpa_config, buf);
242 	u8 *buf;
243 
244 	if (copy_from_user(&config, c, size))
245 		return -EFAULT;
246 	if (vhost_vdpa_config_validate(v, &config))
247 		return -EINVAL;
248 
249 	buf = vmemdup_user(c->buf, config.len);
250 	if (IS_ERR(buf))
251 		return PTR_ERR(buf);
252 
253 	ops->set_config(vdpa, config.off, buf, config.len);
254 
255 	kvfree(buf);
256 	return 0;
257 }
258 
259 static long vhost_vdpa_get_features(struct vhost_vdpa *v, u64 __user *featurep)
260 {
261 	struct vdpa_device *vdpa = v->vdpa;
262 	const struct vdpa_config_ops *ops = vdpa->config;
263 	u64 features;
264 
265 	features = ops->get_features(vdpa);
266 
267 	if (copy_to_user(featurep, &features, sizeof(features)))
268 		return -EFAULT;
269 
270 	return 0;
271 }
272 
273 static long vhost_vdpa_set_features(struct vhost_vdpa *v, u64 __user *featurep)
274 {
275 	struct vdpa_device *vdpa = v->vdpa;
276 	const struct vdpa_config_ops *ops = vdpa->config;
277 	u64 features;
278 
279 	/*
280 	 * It's not allowed to change the features after they have
281 	 * been negotiated.
282 	 */
283 	if (ops->get_status(vdpa) & VIRTIO_CONFIG_S_FEATURES_OK)
284 		return -EBUSY;
285 
286 	if (copy_from_user(&features, featurep, sizeof(features)))
287 		return -EFAULT;
288 
289 	if (vdpa_set_features(vdpa, features))
290 		return -EINVAL;
291 
292 	return 0;
293 }
294 
295 static long vhost_vdpa_get_vring_num(struct vhost_vdpa *v, u16 __user *argp)
296 {
297 	struct vdpa_device *vdpa = v->vdpa;
298 	const struct vdpa_config_ops *ops = vdpa->config;
299 	u16 num;
300 
301 	num = ops->get_vq_num_max(vdpa);
302 
303 	if (copy_to_user(argp, &num, sizeof(num)))
304 		return -EFAULT;
305 
306 	return 0;
307 }
308 
309 static void vhost_vdpa_config_put(struct vhost_vdpa *v)
310 {
311 	if (v->config_ctx) {
312 		eventfd_ctx_put(v->config_ctx);
313 		v->config_ctx = NULL;
314 	}
315 }
316 
317 static long vhost_vdpa_set_config_call(struct vhost_vdpa *v, u32 __user *argp)
318 {
319 	struct vdpa_callback cb;
320 	int fd;
321 	struct eventfd_ctx *ctx;
322 
323 	cb.callback = vhost_vdpa_config_cb;
324 	cb.private = v->vdpa;
325 	if (copy_from_user(&fd, argp, sizeof(fd)))
326 		return  -EFAULT;
327 
328 	ctx = fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(fd);
329 	swap(ctx, v->config_ctx);
330 
331 	if (!IS_ERR_OR_NULL(ctx))
332 		eventfd_ctx_put(ctx);
333 
334 	if (IS_ERR(v->config_ctx)) {
335 		long ret = PTR_ERR(v->config_ctx);
336 
337 		v->config_ctx = NULL;
338 		return ret;
339 	}
340 
341 	v->vdpa->config->set_config_cb(v->vdpa, &cb);
342 
343 	return 0;
344 }
345 
346 static long vhost_vdpa_get_iova_range(struct vhost_vdpa *v, u32 __user *argp)
347 {
348 	struct vhost_vdpa_iova_range range = {
349 		.first = v->range.first,
350 		.last = v->range.last,
351 	};
352 
353 	if (copy_to_user(argp, &range, sizeof(range)))
354 		return -EFAULT;
355 	return 0;
356 }
357 
358 static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
359 				   void __user *argp)
360 {
361 	struct vdpa_device *vdpa = v->vdpa;
362 	const struct vdpa_config_ops *ops = vdpa->config;
363 	struct vdpa_vq_state vq_state;
364 	struct vdpa_callback cb;
365 	struct vhost_virtqueue *vq;
366 	struct vhost_vring_state s;
367 	u32 idx;
368 	long r;
369 
370 	r = get_user(idx, (u32 __user *)argp);
371 	if (r < 0)
372 		return r;
373 
374 	if (idx >= v->nvqs)
375 		return -ENOBUFS;
376 
377 	idx = array_index_nospec(idx, v->nvqs);
378 	vq = &v->vqs[idx];
379 
380 	switch (cmd) {
381 	case VHOST_VDPA_SET_VRING_ENABLE:
382 		if (copy_from_user(&s, argp, sizeof(s)))
383 			return -EFAULT;
384 		ops->set_vq_ready(vdpa, idx, s.num);
385 		return 0;
386 	case VHOST_GET_VRING_BASE:
387 		r = ops->get_vq_state(v->vdpa, idx, &vq_state);
388 		if (r)
389 			return r;
390 
391 		vq->last_avail_idx = vq_state.avail_index;
392 		break;
393 	}
394 
395 	r = vhost_vring_ioctl(&v->vdev, cmd, argp);
396 	if (r)
397 		return r;
398 
399 	switch (cmd) {
400 	case VHOST_SET_VRING_ADDR:
401 		if (ops->set_vq_address(vdpa, idx,
402 					(u64)(uintptr_t)vq->desc,
403 					(u64)(uintptr_t)vq->avail,
404 					(u64)(uintptr_t)vq->used))
405 			r = -EINVAL;
406 		break;
407 
408 	case VHOST_SET_VRING_BASE:
409 		vq_state.avail_index = vq->last_avail_idx;
410 		if (ops->set_vq_state(vdpa, idx, &vq_state))
411 			r = -EINVAL;
412 		break;
413 
414 	case VHOST_SET_VRING_CALL:
415 		if (vq->call_ctx.ctx) {
416 			cb.callback = vhost_vdpa_virtqueue_cb;
417 			cb.private = vq;
418 		} else {
419 			cb.callback = NULL;
420 			cb.private = NULL;
421 		}
422 		ops->set_vq_cb(vdpa, idx, &cb);
423 		vhost_vdpa_setup_vq_irq(v, idx);
424 		break;
425 
426 	case VHOST_SET_VRING_NUM:
427 		ops->set_vq_num(vdpa, idx, vq->num);
428 		break;
429 	}
430 
431 	return r;
432 }
433 
434 static long vhost_vdpa_unlocked_ioctl(struct file *filep,
435 				      unsigned int cmd, unsigned long arg)
436 {
437 	struct vhost_vdpa *v = filep->private_data;
438 	struct vhost_dev *d = &v->vdev;
439 	void __user *argp = (void __user *)arg;
440 	u64 __user *featurep = argp;
441 	u64 features;
442 	long r = 0;
443 
444 	if (cmd == VHOST_SET_BACKEND_FEATURES) {
445 		if (copy_from_user(&features, featurep, sizeof(features)))
446 			return -EFAULT;
447 		if (features & ~VHOST_VDPA_BACKEND_FEATURES)
448 			return -EOPNOTSUPP;
449 		vhost_set_backend_features(&v->vdev, features);
450 		return 0;
451 	}
452 
453 	mutex_lock(&d->mutex);
454 
455 	switch (cmd) {
456 	case VHOST_VDPA_GET_DEVICE_ID:
457 		r = vhost_vdpa_get_device_id(v, argp);
458 		break;
459 	case VHOST_VDPA_GET_STATUS:
460 		r = vhost_vdpa_get_status(v, argp);
461 		break;
462 	case VHOST_VDPA_SET_STATUS:
463 		r = vhost_vdpa_set_status(v, argp);
464 		break;
465 	case VHOST_VDPA_GET_CONFIG:
466 		r = vhost_vdpa_get_config(v, argp);
467 		break;
468 	case VHOST_VDPA_SET_CONFIG:
469 		r = vhost_vdpa_set_config(v, argp);
470 		break;
471 	case VHOST_GET_FEATURES:
472 		r = vhost_vdpa_get_features(v, argp);
473 		break;
474 	case VHOST_SET_FEATURES:
475 		r = vhost_vdpa_set_features(v, argp);
476 		break;
477 	case VHOST_VDPA_GET_VRING_NUM:
478 		r = vhost_vdpa_get_vring_num(v, argp);
479 		break;
480 	case VHOST_SET_LOG_BASE:
481 	case VHOST_SET_LOG_FD:
482 		r = -ENOIOCTLCMD;
483 		break;
484 	case VHOST_VDPA_SET_CONFIG_CALL:
485 		r = vhost_vdpa_set_config_call(v, argp);
486 		break;
487 	case VHOST_GET_BACKEND_FEATURES:
488 		features = VHOST_VDPA_BACKEND_FEATURES;
489 		if (copy_to_user(featurep, &features, sizeof(features)))
490 			r = -EFAULT;
491 		break;
492 	case VHOST_VDPA_GET_IOVA_RANGE:
493 		r = vhost_vdpa_get_iova_range(v, argp);
494 		break;
495 	default:
496 		r = vhost_dev_ioctl(&v->vdev, cmd, argp);
497 		if (r == -ENOIOCTLCMD)
498 			r = vhost_vdpa_vring_ioctl(v, cmd, argp);
499 		break;
500 	}
501 
502 	mutex_unlock(&d->mutex);
503 	return r;
504 }
505 
506 static void vhost_vdpa_iotlb_unmap(struct vhost_vdpa *v, u64 start, u64 last)
507 {
508 	struct vhost_dev *dev = &v->vdev;
509 	struct vhost_iotlb *iotlb = dev->iotlb;
510 	struct vhost_iotlb_map *map;
511 	struct page *page;
512 	unsigned long pfn, pinned;
513 
514 	while ((map = vhost_iotlb_itree_first(iotlb, start, last)) != NULL) {
515 		pinned = map->size >> PAGE_SHIFT;
516 		for (pfn = map->addr >> PAGE_SHIFT;
517 		     pinned > 0; pfn++, pinned--) {
518 			page = pfn_to_page(pfn);
519 			if (map->perm & VHOST_ACCESS_WO)
520 				set_page_dirty_lock(page);
521 			unpin_user_page(page);
522 		}
523 		atomic64_sub(map->size >> PAGE_SHIFT, &dev->mm->pinned_vm);
524 		vhost_iotlb_map_free(iotlb, map);
525 	}
526 }
527 
528 static void vhost_vdpa_iotlb_free(struct vhost_vdpa *v)
529 {
530 	struct vhost_dev *dev = &v->vdev;
531 
532 	vhost_vdpa_iotlb_unmap(v, 0ULL, 0ULL - 1);
533 	kfree(dev->iotlb);
534 	dev->iotlb = NULL;
535 }
536 
537 static int perm_to_iommu_flags(u32 perm)
538 {
539 	int flags = 0;
540 
541 	switch (perm) {
542 	case VHOST_ACCESS_WO:
543 		flags |= IOMMU_WRITE;
544 		break;
545 	case VHOST_ACCESS_RO:
546 		flags |= IOMMU_READ;
547 		break;
548 	case VHOST_ACCESS_RW:
549 		flags |= (IOMMU_WRITE | IOMMU_READ);
550 		break;
551 	default:
552 		WARN(1, "invalidate vhost IOTLB permission\n");
553 		break;
554 	}
555 
556 	return flags | IOMMU_CACHE;
557 }
558 
559 static int vhost_vdpa_map(struct vhost_vdpa *v,
560 			  u64 iova, u64 size, u64 pa, u32 perm)
561 {
562 	struct vhost_dev *dev = &v->vdev;
563 	struct vdpa_device *vdpa = v->vdpa;
564 	const struct vdpa_config_ops *ops = vdpa->config;
565 	int r = 0;
566 
567 	r = vhost_iotlb_add_range(dev->iotlb, iova, iova + size - 1,
568 				  pa, perm);
569 	if (r)
570 		return r;
571 
572 	if (ops->dma_map) {
573 		r = ops->dma_map(vdpa, iova, size, pa, perm);
574 	} else if (ops->set_map) {
575 		if (!v->in_batch)
576 			r = ops->set_map(vdpa, dev->iotlb);
577 	} else {
578 		r = iommu_map(v->domain, iova, pa, size,
579 			      perm_to_iommu_flags(perm));
580 	}
581 
582 	if (r)
583 		vhost_iotlb_del_range(dev->iotlb, iova, iova + size - 1);
584 	else
585 		atomic64_add(size >> PAGE_SHIFT, &dev->mm->pinned_vm);
586 
587 	return r;
588 }
589 
590 static void vhost_vdpa_unmap(struct vhost_vdpa *v, u64 iova, u64 size)
591 {
592 	struct vhost_dev *dev = &v->vdev;
593 	struct vdpa_device *vdpa = v->vdpa;
594 	const struct vdpa_config_ops *ops = vdpa->config;
595 
596 	vhost_vdpa_iotlb_unmap(v, iova, iova + size - 1);
597 
598 	if (ops->dma_map) {
599 		ops->dma_unmap(vdpa, iova, size);
600 	} else if (ops->set_map) {
601 		if (!v->in_batch)
602 			ops->set_map(vdpa, dev->iotlb);
603 	} else {
604 		iommu_unmap(v->domain, iova, size);
605 	}
606 }
607 
608 static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
609 					   struct vhost_iotlb_msg *msg)
610 {
611 	struct vhost_dev *dev = &v->vdev;
612 	struct vhost_iotlb *iotlb = dev->iotlb;
613 	struct page **page_list;
614 	unsigned long list_size = PAGE_SIZE / sizeof(struct page *);
615 	unsigned int gup_flags = FOLL_LONGTERM;
616 	unsigned long npages, cur_base, map_pfn, last_pfn = 0;
617 	unsigned long lock_limit, sz2pin, nchunks, i;
618 	u64 iova = msg->iova;
619 	long pinned;
620 	int ret = 0;
621 
622 	if (msg->iova < v->range.first ||
623 	    msg->iova + msg->size - 1 > v->range.last)
624 		return -EINVAL;
625 
626 	if (vhost_iotlb_itree_first(iotlb, msg->iova,
627 				    msg->iova + msg->size - 1))
628 		return -EEXIST;
629 
630 	/* Limit the use of memory for bookkeeping */
631 	page_list = (struct page **) __get_free_page(GFP_KERNEL);
632 	if (!page_list)
633 		return -ENOMEM;
634 
635 	if (msg->perm & VHOST_ACCESS_WO)
636 		gup_flags |= FOLL_WRITE;
637 
638 	npages = PAGE_ALIGN(msg->size + (iova & ~PAGE_MASK)) >> PAGE_SHIFT;
639 	if (!npages) {
640 		ret = -EINVAL;
641 		goto free;
642 	}
643 
644 	mmap_read_lock(dev->mm);
645 
646 	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
647 	if (npages + atomic64_read(&dev->mm->pinned_vm) > lock_limit) {
648 		ret = -ENOMEM;
649 		goto unlock;
650 	}
651 
652 	cur_base = msg->uaddr & PAGE_MASK;
653 	iova &= PAGE_MASK;
654 	nchunks = 0;
655 
656 	while (npages) {
657 		sz2pin = min_t(unsigned long, npages, list_size);
658 		pinned = pin_user_pages(cur_base, sz2pin,
659 					gup_flags, page_list, NULL);
660 		if (sz2pin != pinned) {
661 			if (pinned < 0) {
662 				ret = pinned;
663 			} else {
664 				unpin_user_pages(page_list, pinned);
665 				ret = -ENOMEM;
666 			}
667 			goto out;
668 		}
669 		nchunks++;
670 
671 		if (!last_pfn)
672 			map_pfn = page_to_pfn(page_list[0]);
673 
674 		for (i = 0; i < pinned; i++) {
675 			unsigned long this_pfn = page_to_pfn(page_list[i]);
676 			u64 csize;
677 
678 			if (last_pfn && (this_pfn != last_pfn + 1)) {
679 				/* Pin a contiguous chunk of memory */
680 				csize = (last_pfn - map_pfn + 1) << PAGE_SHIFT;
681 				ret = vhost_vdpa_map(v, iova, csize,
682 						     map_pfn << PAGE_SHIFT,
683 						     msg->perm);
684 				if (ret) {
685 					/*
686 					 * Unpin the pages that are left unmapped
687 					 * from this point on in the current
688 					 * page_list. The remaining outstanding
689 					 * ones which may stride across several
690 					 * chunks will be covered in the common
691 					 * error path subsequently.
692 					 */
693 					unpin_user_pages(&page_list[i],
694 							 pinned - i);
695 					goto out;
696 				}
697 
698 				map_pfn = this_pfn;
699 				iova += csize;
700 				nchunks = 0;
701 			}
702 
703 			last_pfn = this_pfn;
704 		}
705 
706 		cur_base += pinned << PAGE_SHIFT;
707 		npages -= pinned;
708 	}
709 
710 	/* Pin the rest chunk */
711 	ret = vhost_vdpa_map(v, iova, (last_pfn - map_pfn + 1) << PAGE_SHIFT,
712 			     map_pfn << PAGE_SHIFT, msg->perm);
713 out:
714 	if (ret) {
715 		if (nchunks) {
716 			unsigned long pfn;
717 
718 			/*
719 			 * Unpin the outstanding pages which are yet to be
720 			 * mapped but haven't due to vdpa_map() or
721 			 * pin_user_pages() failure.
722 			 *
723 			 * Mapped pages are accounted in vdpa_map(), hence
724 			 * the corresponding unpinning will be handled by
725 			 * vdpa_unmap().
726 			 */
727 			WARN_ON(!last_pfn);
728 			for (pfn = map_pfn; pfn <= last_pfn; pfn++)
729 				unpin_user_page(pfn_to_page(pfn));
730 		}
731 		vhost_vdpa_unmap(v, msg->iova, msg->size);
732 	}
733 unlock:
734 	mmap_read_unlock(dev->mm);
735 free:
736 	free_page((unsigned long)page_list);
737 	return ret;
738 }
739 
740 static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
741 					struct vhost_iotlb_msg *msg)
742 {
743 	struct vhost_vdpa *v = container_of(dev, struct vhost_vdpa, vdev);
744 	struct vdpa_device *vdpa = v->vdpa;
745 	const struct vdpa_config_ops *ops = vdpa->config;
746 	int r = 0;
747 
748 	mutex_lock(&dev->mutex);
749 
750 	r = vhost_dev_check_owner(dev);
751 	if (r)
752 		goto unlock;
753 
754 	switch (msg->type) {
755 	case VHOST_IOTLB_UPDATE:
756 		r = vhost_vdpa_process_iotlb_update(v, msg);
757 		break;
758 	case VHOST_IOTLB_INVALIDATE:
759 		vhost_vdpa_unmap(v, msg->iova, msg->size);
760 		break;
761 	case VHOST_IOTLB_BATCH_BEGIN:
762 		v->in_batch = true;
763 		break;
764 	case VHOST_IOTLB_BATCH_END:
765 		if (v->in_batch && ops->set_map)
766 			ops->set_map(vdpa, dev->iotlb);
767 		v->in_batch = false;
768 		break;
769 	default:
770 		r = -EINVAL;
771 		break;
772 	}
773 unlock:
774 	mutex_unlock(&dev->mutex);
775 
776 	return r;
777 }
778 
779 static ssize_t vhost_vdpa_chr_write_iter(struct kiocb *iocb,
780 					 struct iov_iter *from)
781 {
782 	struct file *file = iocb->ki_filp;
783 	struct vhost_vdpa *v = file->private_data;
784 	struct vhost_dev *dev = &v->vdev;
785 
786 	return vhost_chr_write_iter(dev, from);
787 }
788 
789 static int vhost_vdpa_alloc_domain(struct vhost_vdpa *v)
790 {
791 	struct vdpa_device *vdpa = v->vdpa;
792 	const struct vdpa_config_ops *ops = vdpa->config;
793 	struct device *dma_dev = vdpa_get_dma_dev(vdpa);
794 	struct bus_type *bus;
795 	int ret;
796 
797 	/* Device want to do DMA by itself */
798 	if (ops->set_map || ops->dma_map)
799 		return 0;
800 
801 	bus = dma_dev->bus;
802 	if (!bus)
803 		return -EFAULT;
804 
805 	if (!iommu_capable(bus, IOMMU_CAP_CACHE_COHERENCY))
806 		return -ENOTSUPP;
807 
808 	v->domain = iommu_domain_alloc(bus);
809 	if (!v->domain)
810 		return -EIO;
811 
812 	ret = iommu_attach_device(v->domain, dma_dev);
813 	if (ret)
814 		goto err_attach;
815 
816 	return 0;
817 
818 err_attach:
819 	iommu_domain_free(v->domain);
820 	return ret;
821 }
822 
823 static void vhost_vdpa_free_domain(struct vhost_vdpa *v)
824 {
825 	struct vdpa_device *vdpa = v->vdpa;
826 	struct device *dma_dev = vdpa_get_dma_dev(vdpa);
827 
828 	if (v->domain) {
829 		iommu_detach_device(v->domain, dma_dev);
830 		iommu_domain_free(v->domain);
831 	}
832 
833 	v->domain = NULL;
834 }
835 
836 static void vhost_vdpa_set_iova_range(struct vhost_vdpa *v)
837 {
838 	struct vdpa_iova_range *range = &v->range;
839 	struct iommu_domain_geometry geo;
840 	struct vdpa_device *vdpa = v->vdpa;
841 	const struct vdpa_config_ops *ops = vdpa->config;
842 
843 	if (ops->get_iova_range) {
844 		*range = ops->get_iova_range(vdpa);
845 	} else if (v->domain &&
846 		   !iommu_domain_get_attr(v->domain,
847 		   DOMAIN_ATTR_GEOMETRY, &geo) &&
848 		   geo.force_aperture) {
849 		range->first = geo.aperture_start;
850 		range->last = geo.aperture_end;
851 	} else {
852 		range->first = 0;
853 		range->last = ULLONG_MAX;
854 	}
855 }
856 
857 static int vhost_vdpa_open(struct inode *inode, struct file *filep)
858 {
859 	struct vhost_vdpa *v;
860 	struct vhost_dev *dev;
861 	struct vhost_virtqueue **vqs;
862 	int nvqs, i, r, opened;
863 
864 	v = container_of(inode->i_cdev, struct vhost_vdpa, cdev);
865 
866 	opened = atomic_cmpxchg(&v->opened, 0, 1);
867 	if (opened)
868 		return -EBUSY;
869 
870 	nvqs = v->nvqs;
871 	vhost_vdpa_reset(v);
872 
873 	vqs = kmalloc_array(nvqs, sizeof(*vqs), GFP_KERNEL);
874 	if (!vqs) {
875 		r = -ENOMEM;
876 		goto err;
877 	}
878 
879 	dev = &v->vdev;
880 	for (i = 0; i < nvqs; i++) {
881 		vqs[i] = &v->vqs[i];
882 		vqs[i]->handle_kick = handle_vq_kick;
883 	}
884 	vhost_dev_init(dev, vqs, nvqs, 0, 0, 0, false,
885 		       vhost_vdpa_process_iotlb_msg);
886 
887 	dev->iotlb = vhost_iotlb_alloc(0, 0);
888 	if (!dev->iotlb) {
889 		r = -ENOMEM;
890 		goto err_init_iotlb;
891 	}
892 
893 	r = vhost_vdpa_alloc_domain(v);
894 	if (r)
895 		goto err_init_iotlb;
896 
897 	vhost_vdpa_set_iova_range(v);
898 
899 	filep->private_data = v;
900 
901 	return 0;
902 
903 err_init_iotlb:
904 	vhost_dev_cleanup(&v->vdev);
905 	kfree(vqs);
906 err:
907 	atomic_dec(&v->opened);
908 	return r;
909 }
910 
911 static void vhost_vdpa_clean_irq(struct vhost_vdpa *v)
912 {
913 	int i;
914 
915 	for (i = 0; i < v->nvqs; i++)
916 		vhost_vdpa_unsetup_vq_irq(v, i);
917 }
918 
919 static int vhost_vdpa_release(struct inode *inode, struct file *filep)
920 {
921 	struct vhost_vdpa *v = filep->private_data;
922 	struct vhost_dev *d = &v->vdev;
923 
924 	mutex_lock(&d->mutex);
925 	filep->private_data = NULL;
926 	vhost_vdpa_reset(v);
927 	vhost_dev_stop(&v->vdev);
928 	vhost_vdpa_iotlb_free(v);
929 	vhost_vdpa_free_domain(v);
930 	vhost_vdpa_config_put(v);
931 	vhost_vdpa_clean_irq(v);
932 	vhost_dev_cleanup(&v->vdev);
933 	kfree(v->vdev.vqs);
934 	mutex_unlock(&d->mutex);
935 
936 	atomic_dec(&v->opened);
937 	complete(&v->completion);
938 
939 	return 0;
940 }
941 
942 #ifdef CONFIG_MMU
943 static vm_fault_t vhost_vdpa_fault(struct vm_fault *vmf)
944 {
945 	struct vhost_vdpa *v = vmf->vma->vm_file->private_data;
946 	struct vdpa_device *vdpa = v->vdpa;
947 	const struct vdpa_config_ops *ops = vdpa->config;
948 	struct vdpa_notification_area notify;
949 	struct vm_area_struct *vma = vmf->vma;
950 	u16 index = vma->vm_pgoff;
951 
952 	notify = ops->get_vq_notification(vdpa, index);
953 
954 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
955 	if (remap_pfn_range(vma, vmf->address & PAGE_MASK,
956 			    notify.addr >> PAGE_SHIFT, PAGE_SIZE,
957 			    vma->vm_page_prot))
958 		return VM_FAULT_SIGBUS;
959 
960 	return VM_FAULT_NOPAGE;
961 }
962 
963 static const struct vm_operations_struct vhost_vdpa_vm_ops = {
964 	.fault = vhost_vdpa_fault,
965 };
966 
967 static int vhost_vdpa_mmap(struct file *file, struct vm_area_struct *vma)
968 {
969 	struct vhost_vdpa *v = vma->vm_file->private_data;
970 	struct vdpa_device *vdpa = v->vdpa;
971 	const struct vdpa_config_ops *ops = vdpa->config;
972 	struct vdpa_notification_area notify;
973 	unsigned long index = vma->vm_pgoff;
974 
975 	if (vma->vm_end - vma->vm_start != PAGE_SIZE)
976 		return -EINVAL;
977 	if ((vma->vm_flags & VM_SHARED) == 0)
978 		return -EINVAL;
979 	if (vma->vm_flags & VM_READ)
980 		return -EINVAL;
981 	if (index > 65535)
982 		return -EINVAL;
983 	if (!ops->get_vq_notification)
984 		return -ENOTSUPP;
985 
986 	/* To be safe and easily modelled by userspace, We only
987 	 * support the doorbell which sits on the page boundary and
988 	 * does not share the page with other registers.
989 	 */
990 	notify = ops->get_vq_notification(vdpa, index);
991 	if (notify.addr & (PAGE_SIZE - 1))
992 		return -EINVAL;
993 	if (vma->vm_end - vma->vm_start != notify.size)
994 		return -ENOTSUPP;
995 
996 	vma->vm_ops = &vhost_vdpa_vm_ops;
997 	return 0;
998 }
999 #endif /* CONFIG_MMU */
1000 
1001 static const struct file_operations vhost_vdpa_fops = {
1002 	.owner		= THIS_MODULE,
1003 	.open		= vhost_vdpa_open,
1004 	.release	= vhost_vdpa_release,
1005 	.write_iter	= vhost_vdpa_chr_write_iter,
1006 	.unlocked_ioctl	= vhost_vdpa_unlocked_ioctl,
1007 #ifdef CONFIG_MMU
1008 	.mmap		= vhost_vdpa_mmap,
1009 #endif /* CONFIG_MMU */
1010 	.compat_ioctl	= compat_ptr_ioctl,
1011 };
1012 
1013 static void vhost_vdpa_release_dev(struct device *device)
1014 {
1015 	struct vhost_vdpa *v =
1016 	       container_of(device, struct vhost_vdpa, dev);
1017 
1018 	ida_simple_remove(&vhost_vdpa_ida, v->minor);
1019 	kfree(v->vqs);
1020 	kfree(v);
1021 }
1022 
1023 static int vhost_vdpa_probe(struct vdpa_device *vdpa)
1024 {
1025 	const struct vdpa_config_ops *ops = vdpa->config;
1026 	struct vhost_vdpa *v;
1027 	int minor;
1028 	int r;
1029 
1030 	/* Currently, we only accept the network devices. */
1031 	if (ops->get_device_id(vdpa) != VIRTIO_ID_NET)
1032 		return -ENOTSUPP;
1033 
1034 	v = kzalloc(sizeof(*v), GFP_KERNEL | __GFP_RETRY_MAYFAIL);
1035 	if (!v)
1036 		return -ENOMEM;
1037 
1038 	minor = ida_simple_get(&vhost_vdpa_ida, 0,
1039 			       VHOST_VDPA_DEV_MAX, GFP_KERNEL);
1040 	if (minor < 0) {
1041 		kfree(v);
1042 		return minor;
1043 	}
1044 
1045 	atomic_set(&v->opened, 0);
1046 	v->minor = minor;
1047 	v->vdpa = vdpa;
1048 	v->nvqs = vdpa->nvqs;
1049 	v->virtio_id = ops->get_device_id(vdpa);
1050 
1051 	device_initialize(&v->dev);
1052 	v->dev.release = vhost_vdpa_release_dev;
1053 	v->dev.parent = &vdpa->dev;
1054 	v->dev.devt = MKDEV(MAJOR(vhost_vdpa_major), minor);
1055 	v->vqs = kmalloc_array(v->nvqs, sizeof(struct vhost_virtqueue),
1056 			       GFP_KERNEL);
1057 	if (!v->vqs) {
1058 		r = -ENOMEM;
1059 		goto err;
1060 	}
1061 
1062 	r = dev_set_name(&v->dev, "vhost-vdpa-%u", minor);
1063 	if (r)
1064 		goto err;
1065 
1066 	cdev_init(&v->cdev, &vhost_vdpa_fops);
1067 	v->cdev.owner = THIS_MODULE;
1068 
1069 	r = cdev_device_add(&v->cdev, &v->dev);
1070 	if (r)
1071 		goto err;
1072 
1073 	init_completion(&v->completion);
1074 	vdpa_set_drvdata(vdpa, v);
1075 
1076 	return 0;
1077 
1078 err:
1079 	put_device(&v->dev);
1080 	return r;
1081 }
1082 
1083 static void vhost_vdpa_remove(struct vdpa_device *vdpa)
1084 {
1085 	struct vhost_vdpa *v = vdpa_get_drvdata(vdpa);
1086 	int opened;
1087 
1088 	cdev_device_del(&v->cdev, &v->dev);
1089 
1090 	do {
1091 		opened = atomic_cmpxchg(&v->opened, 0, 1);
1092 		if (!opened)
1093 			break;
1094 		wait_for_completion(&v->completion);
1095 	} while (1);
1096 
1097 	put_device(&v->dev);
1098 }
1099 
1100 static struct vdpa_driver vhost_vdpa_driver = {
1101 	.driver = {
1102 		.name	= "vhost_vdpa",
1103 	},
1104 	.probe	= vhost_vdpa_probe,
1105 	.remove	= vhost_vdpa_remove,
1106 };
1107 
1108 static int __init vhost_vdpa_init(void)
1109 {
1110 	int r;
1111 
1112 	r = alloc_chrdev_region(&vhost_vdpa_major, 0, VHOST_VDPA_DEV_MAX,
1113 				"vhost-vdpa");
1114 	if (r)
1115 		goto err_alloc_chrdev;
1116 
1117 	r = vdpa_register_driver(&vhost_vdpa_driver);
1118 	if (r)
1119 		goto err_vdpa_register_driver;
1120 
1121 	return 0;
1122 
1123 err_vdpa_register_driver:
1124 	unregister_chrdev_region(vhost_vdpa_major, VHOST_VDPA_DEV_MAX);
1125 err_alloc_chrdev:
1126 	return r;
1127 }
1128 module_init(vhost_vdpa_init);
1129 
1130 static void __exit vhost_vdpa_exit(void)
1131 {
1132 	vdpa_unregister_driver(&vhost_vdpa_driver);
1133 	unregister_chrdev_region(vhost_vdpa_major, VHOST_VDPA_DEV_MAX);
1134 }
1135 module_exit(vhost_vdpa_exit);
1136 
1137 MODULE_VERSION("0.0.1");
1138 MODULE_LICENSE("GPL v2");
1139 MODULE_AUTHOR("Intel Corporation");
1140 MODULE_DESCRIPTION("vDPA-based vhost backend for virtio");
1141