Commit | Line | Data |
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3a4d5c94 MT |
1 | /* Copyright (C) 2009 Red Hat, Inc. |
2 | * Copyright (C) 2006 Rusty Russell IBM Corporation | |
3 | * | |
4 | * Author: Michael S. Tsirkin <mst@redhat.com> | |
5 | * | |
6 | * Inspiration, some code, and most witty comments come from | |
61516587 | 7 | * Documentation/virtual/lguest/lguest.c, by Rusty Russell |
3a4d5c94 MT |
8 | * |
9 | * This work is licensed under the terms of the GNU GPL, version 2. | |
10 | * | |
11 | * Generic code for virtio server in host kernel. | |
12 | */ | |
13 | ||
14 | #include <linux/eventfd.h> | |
15 | #include <linux/vhost.h> | |
16 | #include <linux/virtio_net.h> | |
17 | #include <linux/mm.h> | |
64e1c807 | 18 | #include <linux/mmu_context.h> |
3a4d5c94 MT |
19 | #include <linux/miscdevice.h> |
20 | #include <linux/mutex.h> | |
3a4d5c94 MT |
21 | #include <linux/rcupdate.h> |
22 | #include <linux/poll.h> | |
23 | #include <linux/file.h> | |
24 | #include <linux/highmem.h> | |
5a0e3ad6 | 25 | #include <linux/slab.h> |
c23f3445 | 26 | #include <linux/kthread.h> |
9e3d1957 | 27 | #include <linux/cgroup.h> |
3a4d5c94 | 28 | |
3a4d5c94 MT |
29 | #include "vhost.h" |
30 | ||
31 | enum { | |
32 | VHOST_MEMORY_MAX_NREGIONS = 64, | |
33 | VHOST_MEMORY_F_LOG = 0x1, | |
34 | }; | |
35 | ||
bab632d6 MT |
36 | static unsigned vhost_zcopy_mask __read_mostly; |
37 | ||
8ea8cf89 MT |
38 | #define vhost_used_event(vq) ((u16 __user *)&vq->avail->ring[vq->num]) |
39 | #define vhost_avail_event(vq) ((u16 __user *)&vq->used->ring[vq->num]) | |
40 | ||
3a4d5c94 MT |
41 | static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh, |
42 | poll_table *pt) | |
43 | { | |
44 | struct vhost_poll *poll; | |
3a4d5c94 | 45 | |
d47effe1 | 46 | poll = container_of(pt, struct vhost_poll, table); |
3a4d5c94 MT |
47 | poll->wqh = wqh; |
48 | add_wait_queue(wqh, &poll->wait); | |
49 | } | |
50 | ||
51 | static int vhost_poll_wakeup(wait_queue_t *wait, unsigned mode, int sync, | |
52 | void *key) | |
53 | { | |
c23f3445 TH |
54 | struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait); |
55 | ||
3a4d5c94 MT |
56 | if (!((unsigned long)key & poll->mask)) |
57 | return 0; | |
58 | ||
c23f3445 | 59 | vhost_poll_queue(poll); |
3a4d5c94 MT |
60 | return 0; |
61 | } | |
62 | ||
163049ae | 63 | void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn) |
87d6a412 MT |
64 | { |
65 | INIT_LIST_HEAD(&work->node); | |
66 | work->fn = fn; | |
67 | init_waitqueue_head(&work->done); | |
68 | work->flushing = 0; | |
69 | work->queue_seq = work->done_seq = 0; | |
70 | } | |
71 | ||
3a4d5c94 | 72 | /* Init poll structure */ |
c23f3445 TH |
73 | void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, |
74 | unsigned long mask, struct vhost_dev *dev) | |
3a4d5c94 | 75 | { |
3a4d5c94 MT |
76 | init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup); |
77 | init_poll_funcptr(&poll->table, vhost_poll_func); | |
78 | poll->mask = mask; | |
c23f3445 | 79 | poll->dev = dev; |
2b8b328b | 80 | poll->wqh = NULL; |
c23f3445 | 81 | |
87d6a412 | 82 | vhost_work_init(&poll->work, fn); |
3a4d5c94 MT |
83 | } |
84 | ||
85 | /* Start polling a file. We add ourselves to file's wait queue. The caller must | |
86 | * keep a reference to a file until after vhost_poll_stop is called. */ | |
2b8b328b | 87 | int vhost_poll_start(struct vhost_poll *poll, struct file *file) |
3a4d5c94 MT |
88 | { |
89 | unsigned long mask; | |
2b8b328b | 90 | int ret = 0; |
d47effe1 | 91 | |
70181d51 JW |
92 | if (poll->wqh) |
93 | return 0; | |
94 | ||
3a4d5c94 MT |
95 | mask = file->f_op->poll(file, &poll->table); |
96 | if (mask) | |
97 | vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask); | |
2b8b328b JW |
98 | if (mask & POLLERR) { |
99 | if (poll->wqh) | |
100 | remove_wait_queue(poll->wqh, &poll->wait); | |
101 | ret = -EINVAL; | |
102 | } | |
103 | ||
104 | return ret; | |
3a4d5c94 MT |
105 | } |
106 | ||
107 | /* Stop polling a file. After this function returns, it becomes safe to drop the | |
108 | * file reference. You must also flush afterwards. */ | |
109 | void vhost_poll_stop(struct vhost_poll *poll) | |
110 | { | |
2b8b328b JW |
111 | if (poll->wqh) { |
112 | remove_wait_queue(poll->wqh, &poll->wait); | |
113 | poll->wqh = NULL; | |
114 | } | |
3a4d5c94 MT |
115 | } |
116 | ||
0174b0c3 MT |
117 | static bool vhost_work_seq_done(struct vhost_dev *dev, struct vhost_work *work, |
118 | unsigned seq) | |
119 | { | |
120 | int left; | |
d47effe1 | 121 | |
0174b0c3 MT |
122 | spin_lock_irq(&dev->work_lock); |
123 | left = seq - work->done_seq; | |
124 | spin_unlock_irq(&dev->work_lock); | |
125 | return left <= 0; | |
126 | } | |
127 | ||
87d6a412 | 128 | static void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work) |
3a4d5c94 | 129 | { |
c23f3445 | 130 | unsigned seq; |
c23f3445 TH |
131 | int flushing; |
132 | ||
87d6a412 | 133 | spin_lock_irq(&dev->work_lock); |
c23f3445 TH |
134 | seq = work->queue_seq; |
135 | work->flushing++; | |
87d6a412 | 136 | spin_unlock_irq(&dev->work_lock); |
0174b0c3 | 137 | wait_event(work->done, vhost_work_seq_done(dev, work, seq)); |
87d6a412 | 138 | spin_lock_irq(&dev->work_lock); |
c23f3445 | 139 | flushing = --work->flushing; |
87d6a412 | 140 | spin_unlock_irq(&dev->work_lock); |
c23f3445 | 141 | BUG_ON(flushing < 0); |
3a4d5c94 MT |
142 | } |
143 | ||
87d6a412 MT |
144 | /* Flush any work that has been scheduled. When calling this, don't hold any |
145 | * locks that are also used by the callback. */ | |
146 | void vhost_poll_flush(struct vhost_poll *poll) | |
147 | { | |
148 | vhost_work_flush(poll->dev, &poll->work); | |
149 | } | |
150 | ||
163049ae | 151 | void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work) |
3a4d5c94 | 152 | { |
c23f3445 TH |
153 | unsigned long flags; |
154 | ||
155 | spin_lock_irqsave(&dev->work_lock, flags); | |
156 | if (list_empty(&work->node)) { | |
157 | list_add_tail(&work->node, &dev->work_list); | |
158 | work->queue_seq++; | |
159 | wake_up_process(dev->worker); | |
160 | } | |
161 | spin_unlock_irqrestore(&dev->work_lock, flags); | |
3a4d5c94 MT |
162 | } |
163 | ||
87d6a412 MT |
164 | void vhost_poll_queue(struct vhost_poll *poll) |
165 | { | |
166 | vhost_work_queue(poll->dev, &poll->work); | |
167 | } | |
168 | ||
3a4d5c94 MT |
169 | static void vhost_vq_reset(struct vhost_dev *dev, |
170 | struct vhost_virtqueue *vq) | |
171 | { | |
172 | vq->num = 1; | |
173 | vq->desc = NULL; | |
174 | vq->avail = NULL; | |
175 | vq->used = NULL; | |
176 | vq->last_avail_idx = 0; | |
177 | vq->avail_idx = 0; | |
178 | vq->last_used_idx = 0; | |
8ea8cf89 MT |
179 | vq->signalled_used = 0; |
180 | vq->signalled_used_valid = false; | |
3a4d5c94 | 181 | vq->used_flags = 0; |
3a4d5c94 MT |
182 | vq->log_used = false; |
183 | vq->log_addr = -1ull; | |
8dd014ad DS |
184 | vq->vhost_hlen = 0; |
185 | vq->sock_hlen = 0; | |
3a4d5c94 MT |
186 | vq->private_data = NULL; |
187 | vq->log_base = NULL; | |
188 | vq->error_ctx = NULL; | |
189 | vq->error = NULL; | |
190 | vq->kick = NULL; | |
191 | vq->call_ctx = NULL; | |
192 | vq->call = NULL; | |
73a99f08 | 193 | vq->log_ctx = NULL; |
bab632d6 MT |
194 | vq->upend_idx = 0; |
195 | vq->done_idx = 0; | |
196 | vq->ubufs = NULL; | |
3a4d5c94 MT |
197 | } |
198 | ||
c23f3445 TH |
199 | static int vhost_worker(void *data) |
200 | { | |
201 | struct vhost_dev *dev = data; | |
202 | struct vhost_work *work = NULL; | |
203 | unsigned uninitialized_var(seq); | |
d7ffde35 | 204 | mm_segment_t oldfs = get_fs(); |
c23f3445 | 205 | |
d7ffde35 | 206 | set_fs(USER_DS); |
64e1c807 MT |
207 | use_mm(dev->mm); |
208 | ||
c23f3445 TH |
209 | for (;;) { |
210 | /* mb paired w/ kthread_stop */ | |
211 | set_current_state(TASK_INTERRUPTIBLE); | |
212 | ||
213 | spin_lock_irq(&dev->work_lock); | |
214 | if (work) { | |
215 | work->done_seq = seq; | |
216 | if (work->flushing) | |
217 | wake_up_all(&work->done); | |
218 | } | |
219 | ||
220 | if (kthread_should_stop()) { | |
221 | spin_unlock_irq(&dev->work_lock); | |
222 | __set_current_state(TASK_RUNNING); | |
64e1c807 | 223 | break; |
c23f3445 TH |
224 | } |
225 | if (!list_empty(&dev->work_list)) { | |
226 | work = list_first_entry(&dev->work_list, | |
227 | struct vhost_work, node); | |
228 | list_del_init(&work->node); | |
229 | seq = work->queue_seq; | |
230 | } else | |
231 | work = NULL; | |
232 | spin_unlock_irq(&dev->work_lock); | |
233 | ||
234 | if (work) { | |
235 | __set_current_state(TASK_RUNNING); | |
236 | work->fn(work); | |
d550dda1 NHE |
237 | if (need_resched()) |
238 | schedule(); | |
c23f3445 TH |
239 | } else |
240 | schedule(); | |
241 | ||
242 | } | |
64e1c807 | 243 | unuse_mm(dev->mm); |
d7ffde35 | 244 | set_fs(oldfs); |
64e1c807 | 245 | return 0; |
c23f3445 TH |
246 | } |
247 | ||
bab632d6 MT |
248 | static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq) |
249 | { | |
250 | kfree(vq->indirect); | |
251 | vq->indirect = NULL; | |
252 | kfree(vq->log); | |
253 | vq->log = NULL; | |
254 | kfree(vq->heads); | |
255 | vq->heads = NULL; | |
256 | kfree(vq->ubuf_info); | |
257 | vq->ubuf_info = NULL; | |
258 | } | |
259 | ||
260 | void vhost_enable_zcopy(int vq) | |
261 | { | |
262 | vhost_zcopy_mask |= 0x1 << vq; | |
263 | } | |
264 | ||
e0e9b406 JW |
265 | /* Helper to allocate iovec buffers for all vqs. */ |
266 | static long vhost_dev_alloc_iovecs(struct vhost_dev *dev) | |
267 | { | |
268 | int i; | |
bab632d6 | 269 | bool zcopy; |
d47effe1 | 270 | |
e0e9b406 JW |
271 | for (i = 0; i < dev->nvqs; ++i) { |
272 | dev->vqs[i].indirect = kmalloc(sizeof *dev->vqs[i].indirect * | |
273 | UIO_MAXIOV, GFP_KERNEL); | |
274 | dev->vqs[i].log = kmalloc(sizeof *dev->vqs[i].log * UIO_MAXIOV, | |
275 | GFP_KERNEL); | |
276 | dev->vqs[i].heads = kmalloc(sizeof *dev->vqs[i].heads * | |
277 | UIO_MAXIOV, GFP_KERNEL); | |
bab632d6 MT |
278 | zcopy = vhost_zcopy_mask & (0x1 << i); |
279 | if (zcopy) | |
280 | dev->vqs[i].ubuf_info = | |
281 | kmalloc(sizeof *dev->vqs[i].ubuf_info * | |
282 | UIO_MAXIOV, GFP_KERNEL); | |
e0e9b406 | 283 | if (!dev->vqs[i].indirect || !dev->vqs[i].log || |
bab632d6 MT |
284 | !dev->vqs[i].heads || |
285 | (zcopy && !dev->vqs[i].ubuf_info)) | |
e0e9b406 JW |
286 | goto err_nomem; |
287 | } | |
288 | return 0; | |
d47effe1 | 289 | |
e0e9b406 | 290 | err_nomem: |
bab632d6 MT |
291 | for (; i >= 0; --i) |
292 | vhost_vq_free_iovecs(&dev->vqs[i]); | |
e0e9b406 JW |
293 | return -ENOMEM; |
294 | } | |
295 | ||
296 | static void vhost_dev_free_iovecs(struct vhost_dev *dev) | |
297 | { | |
298 | int i; | |
d47effe1 | 299 | |
bab632d6 MT |
300 | for (i = 0; i < dev->nvqs; ++i) |
301 | vhost_vq_free_iovecs(&dev->vqs[i]); | |
e0e9b406 JW |
302 | } |
303 | ||
3a4d5c94 MT |
304 | long vhost_dev_init(struct vhost_dev *dev, |
305 | struct vhost_virtqueue *vqs, int nvqs) | |
306 | { | |
307 | int i; | |
c23f3445 | 308 | |
3a4d5c94 MT |
309 | dev->vqs = vqs; |
310 | dev->nvqs = nvqs; | |
311 | mutex_init(&dev->mutex); | |
312 | dev->log_ctx = NULL; | |
313 | dev->log_file = NULL; | |
314 | dev->memory = NULL; | |
315 | dev->mm = NULL; | |
c23f3445 TH |
316 | spin_lock_init(&dev->work_lock); |
317 | INIT_LIST_HEAD(&dev->work_list); | |
318 | dev->worker = NULL; | |
3a4d5c94 MT |
319 | |
320 | for (i = 0; i < dev->nvqs; ++i) { | |
e0e9b406 JW |
321 | dev->vqs[i].log = NULL; |
322 | dev->vqs[i].indirect = NULL; | |
323 | dev->vqs[i].heads = NULL; | |
bab632d6 | 324 | dev->vqs[i].ubuf_info = NULL; |
3a4d5c94 MT |
325 | dev->vqs[i].dev = dev; |
326 | mutex_init(&dev->vqs[i].mutex); | |
327 | vhost_vq_reset(dev, dev->vqs + i); | |
328 | if (dev->vqs[i].handle_kick) | |
329 | vhost_poll_init(&dev->vqs[i].poll, | |
c23f3445 | 330 | dev->vqs[i].handle_kick, POLLIN, dev); |
3a4d5c94 | 331 | } |
c23f3445 | 332 | |
3a4d5c94 MT |
333 | return 0; |
334 | } | |
335 | ||
336 | /* Caller should have device mutex */ | |
337 | long vhost_dev_check_owner(struct vhost_dev *dev) | |
338 | { | |
339 | /* Are you the owner? If not, I don't think you mean to do that */ | |
340 | return dev->mm == current->mm ? 0 : -EPERM; | |
341 | } | |
342 | ||
87d6a412 | 343 | struct vhost_attach_cgroups_struct { |
d47effe1 KK |
344 | struct vhost_work work; |
345 | struct task_struct *owner; | |
346 | int ret; | |
87d6a412 MT |
347 | }; |
348 | ||
349 | static void vhost_attach_cgroups_work(struct vhost_work *work) | |
350 | { | |
d47effe1 KK |
351 | struct vhost_attach_cgroups_struct *s; |
352 | ||
353 | s = container_of(work, struct vhost_attach_cgroups_struct, work); | |
354 | s->ret = cgroup_attach_task_all(s->owner, current); | |
87d6a412 MT |
355 | } |
356 | ||
357 | static int vhost_attach_cgroups(struct vhost_dev *dev) | |
358 | { | |
d47effe1 KK |
359 | struct vhost_attach_cgroups_struct attach; |
360 | ||
361 | attach.owner = current; | |
362 | vhost_work_init(&attach.work, vhost_attach_cgroups_work); | |
363 | vhost_work_queue(dev, &attach.work); | |
364 | vhost_work_flush(dev, &attach.work); | |
365 | return attach.ret; | |
87d6a412 MT |
366 | } |
367 | ||
3a4d5c94 MT |
368 | /* Caller should have device mutex */ |
369 | static long vhost_dev_set_owner(struct vhost_dev *dev) | |
370 | { | |
c23f3445 TH |
371 | struct task_struct *worker; |
372 | int err; | |
d47effe1 | 373 | |
3a4d5c94 | 374 | /* Is there an owner already? */ |
c23f3445 TH |
375 | if (dev->mm) { |
376 | err = -EBUSY; | |
377 | goto err_mm; | |
378 | } | |
d47effe1 | 379 | |
3a4d5c94 MT |
380 | /* No owner, become one */ |
381 | dev->mm = get_task_mm(current); | |
c23f3445 TH |
382 | worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid); |
383 | if (IS_ERR(worker)) { | |
384 | err = PTR_ERR(worker); | |
385 | goto err_worker; | |
386 | } | |
387 | ||
388 | dev->worker = worker; | |
87d6a412 MT |
389 | wake_up_process(worker); /* avoid contributing to loadavg */ |
390 | ||
391 | err = vhost_attach_cgroups(dev); | |
9e3d1957 MT |
392 | if (err) |
393 | goto err_cgroup; | |
c23f3445 | 394 | |
e0e9b406 JW |
395 | err = vhost_dev_alloc_iovecs(dev); |
396 | if (err) | |
397 | goto err_cgroup; | |
398 | ||
3a4d5c94 | 399 | return 0; |
9e3d1957 MT |
400 | err_cgroup: |
401 | kthread_stop(worker); | |
615cc221 | 402 | dev->worker = NULL; |
c23f3445 TH |
403 | err_worker: |
404 | if (dev->mm) | |
405 | mmput(dev->mm); | |
406 | dev->mm = NULL; | |
407 | err_mm: | |
408 | return err; | |
3a4d5c94 MT |
409 | } |
410 | ||
411 | /* Caller should have device mutex */ | |
412 | long vhost_dev_reset_owner(struct vhost_dev *dev) | |
413 | { | |
414 | struct vhost_memory *memory; | |
415 | ||
416 | /* Restore memory to default empty mapping. */ | |
417 | memory = kmalloc(offsetof(struct vhost_memory, regions), GFP_KERNEL); | |
418 | if (!memory) | |
419 | return -ENOMEM; | |
420 | ||
ea5d4046 | 421 | vhost_dev_cleanup(dev, true); |
3a4d5c94 MT |
422 | |
423 | memory->nregions = 0; | |
28457ee6 | 424 | RCU_INIT_POINTER(dev->memory, memory); |
3a4d5c94 MT |
425 | return 0; |
426 | } | |
427 | ||
b211616d | 428 | void vhost_dev_stop(struct vhost_dev *dev) |
bab632d6 MT |
429 | { |
430 | int i; | |
b211616d MT |
431 | |
432 | for (i = 0; i < dev->nvqs; ++i) { | |
433 | if (dev->vqs[i].kick && dev->vqs[i].handle_kick) { | |
434 | vhost_poll_stop(&dev->vqs[i].poll); | |
435 | vhost_poll_flush(&dev->vqs[i].poll); | |
436 | } | |
bab632d6 | 437 | } |
bab632d6 MT |
438 | } |
439 | ||
ea5d4046 MT |
440 | /* Caller should have device mutex if and only if locked is set */ |
441 | void vhost_dev_cleanup(struct vhost_dev *dev, bool locked) | |
3a4d5c94 MT |
442 | { |
443 | int i; | |
d47effe1 | 444 | |
3a4d5c94 | 445 | for (i = 0; i < dev->nvqs; ++i) { |
3a4d5c94 MT |
446 | if (dev->vqs[i].error_ctx) |
447 | eventfd_ctx_put(dev->vqs[i].error_ctx); | |
448 | if (dev->vqs[i].error) | |
449 | fput(dev->vqs[i].error); | |
450 | if (dev->vqs[i].kick) | |
451 | fput(dev->vqs[i].kick); | |
452 | if (dev->vqs[i].call_ctx) | |
453 | eventfd_ctx_put(dev->vqs[i].call_ctx); | |
454 | if (dev->vqs[i].call) | |
455 | fput(dev->vqs[i].call); | |
456 | vhost_vq_reset(dev, dev->vqs + i); | |
457 | } | |
e0e9b406 | 458 | vhost_dev_free_iovecs(dev); |
3a4d5c94 MT |
459 | if (dev->log_ctx) |
460 | eventfd_ctx_put(dev->log_ctx); | |
461 | dev->log_ctx = NULL; | |
462 | if (dev->log_file) | |
463 | fput(dev->log_file); | |
464 | dev->log_file = NULL; | |
465 | /* No one will access memory at this point */ | |
28457ee6 | 466 | kfree(rcu_dereference_protected(dev->memory, |
ea5d4046 MT |
467 | locked == |
468 | lockdep_is_held(&dev->mutex))); | |
28457ee6 | 469 | RCU_INIT_POINTER(dev->memory, NULL); |
c23f3445 | 470 | WARN_ON(!list_empty(&dev->work_list)); |
78b620ce ED |
471 | if (dev->worker) { |
472 | kthread_stop(dev->worker); | |
473 | dev->worker = NULL; | |
474 | } | |
533a19b4 MT |
475 | if (dev->mm) |
476 | mmput(dev->mm); | |
477 | dev->mm = NULL; | |
3a4d5c94 MT |
478 | } |
479 | ||
480 | static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz) | |
481 | { | |
482 | u64 a = addr / VHOST_PAGE_SIZE / 8; | |
d47effe1 | 483 | |
3a4d5c94 MT |
484 | /* Make sure 64 bit math will not overflow. */ |
485 | if (a > ULONG_MAX - (unsigned long)log_base || | |
486 | a + (unsigned long)log_base > ULONG_MAX) | |
6d97e55f | 487 | return 0; |
3a4d5c94 MT |
488 | |
489 | return access_ok(VERIFY_WRITE, log_base + a, | |
490 | (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8); | |
491 | } | |
492 | ||
493 | /* Caller should have vq mutex and device mutex. */ | |
494 | static int vq_memory_access_ok(void __user *log_base, struct vhost_memory *mem, | |
495 | int log_all) | |
496 | { | |
497 | int i; | |
179b284e | 498 | |
f8322fbe MT |
499 | if (!mem) |
500 | return 0; | |
179b284e | 501 | |
3a4d5c94 MT |
502 | for (i = 0; i < mem->nregions; ++i) { |
503 | struct vhost_memory_region *m = mem->regions + i; | |
504 | unsigned long a = m->userspace_addr; | |
505 | if (m->memory_size > ULONG_MAX) | |
506 | return 0; | |
507 | else if (!access_ok(VERIFY_WRITE, (void __user *)a, | |
508 | m->memory_size)) | |
509 | return 0; | |
510 | else if (log_all && !log_access_ok(log_base, | |
511 | m->guest_phys_addr, | |
512 | m->memory_size)) | |
513 | return 0; | |
514 | } | |
515 | return 1; | |
516 | } | |
517 | ||
518 | /* Can we switch to this memory table? */ | |
519 | /* Caller should have device mutex but not vq mutex */ | |
520 | static int memory_access_ok(struct vhost_dev *d, struct vhost_memory *mem, | |
521 | int log_all) | |
522 | { | |
523 | int i; | |
d47effe1 | 524 | |
3a4d5c94 MT |
525 | for (i = 0; i < d->nvqs; ++i) { |
526 | int ok; | |
527 | mutex_lock(&d->vqs[i].mutex); | |
528 | /* If ring is inactive, will check when it's enabled. */ | |
529 | if (d->vqs[i].private_data) | |
530 | ok = vq_memory_access_ok(d->vqs[i].log_base, mem, | |
531 | log_all); | |
532 | else | |
533 | ok = 1; | |
534 | mutex_unlock(&d->vqs[i].mutex); | |
535 | if (!ok) | |
536 | return 0; | |
537 | } | |
538 | return 1; | |
539 | } | |
540 | ||
8ea8cf89 | 541 | static int vq_access_ok(struct vhost_dev *d, unsigned int num, |
3a4d5c94 MT |
542 | struct vring_desc __user *desc, |
543 | struct vring_avail __user *avail, | |
544 | struct vring_used __user *used) | |
545 | { | |
8ea8cf89 | 546 | size_t s = vhost_has_feature(d, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; |
3a4d5c94 MT |
547 | return access_ok(VERIFY_READ, desc, num * sizeof *desc) && |
548 | access_ok(VERIFY_READ, avail, | |
8ea8cf89 | 549 | sizeof *avail + num * sizeof *avail->ring + s) && |
3a4d5c94 | 550 | access_ok(VERIFY_WRITE, used, |
8ea8cf89 | 551 | sizeof *used + num * sizeof *used->ring + s); |
3a4d5c94 MT |
552 | } |
553 | ||
554 | /* Can we log writes? */ | |
555 | /* Caller should have device mutex but not vq mutex */ | |
556 | int vhost_log_access_ok(struct vhost_dev *dev) | |
557 | { | |
28457ee6 AB |
558 | struct vhost_memory *mp; |
559 | ||
560 | mp = rcu_dereference_protected(dev->memory, | |
561 | lockdep_is_held(&dev->mutex)); | |
562 | return memory_access_ok(dev, mp, 1); | |
3a4d5c94 MT |
563 | } |
564 | ||
565 | /* Verify access for write logging. */ | |
566 | /* Caller should have vq mutex and device mutex */ | |
8ea8cf89 MT |
567 | static int vq_log_access_ok(struct vhost_dev *d, struct vhost_virtqueue *vq, |
568 | void __user *log_base) | |
3a4d5c94 | 569 | { |
28457ee6 | 570 | struct vhost_memory *mp; |
8ea8cf89 | 571 | size_t s = vhost_has_feature(d, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; |
28457ee6 AB |
572 | |
573 | mp = rcu_dereference_protected(vq->dev->memory, | |
574 | lockdep_is_held(&vq->mutex)); | |
575 | return vq_memory_access_ok(log_base, mp, | |
3a4d5c94 MT |
576 | vhost_has_feature(vq->dev, VHOST_F_LOG_ALL)) && |
577 | (!vq->log_used || log_access_ok(log_base, vq->log_addr, | |
578 | sizeof *vq->used + | |
8ea8cf89 | 579 | vq->num * sizeof *vq->used->ring + s)); |
3a4d5c94 MT |
580 | } |
581 | ||
582 | /* Can we start vq? */ | |
583 | /* Caller should have vq mutex and device mutex */ | |
584 | int vhost_vq_access_ok(struct vhost_virtqueue *vq) | |
585 | { | |
8ea8cf89 MT |
586 | return vq_access_ok(vq->dev, vq->num, vq->desc, vq->avail, vq->used) && |
587 | vq_log_access_ok(vq->dev, vq, vq->log_base); | |
3a4d5c94 MT |
588 | } |
589 | ||
590 | static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) | |
591 | { | |
592 | struct vhost_memory mem, *newmem, *oldmem; | |
593 | unsigned long size = offsetof(struct vhost_memory, regions); | |
d47effe1 | 594 | |
7ad9c9d2 TY |
595 | if (copy_from_user(&mem, m, size)) |
596 | return -EFAULT; | |
3a4d5c94 MT |
597 | if (mem.padding) |
598 | return -EOPNOTSUPP; | |
599 | if (mem.nregions > VHOST_MEMORY_MAX_NREGIONS) | |
600 | return -E2BIG; | |
601 | newmem = kmalloc(size + mem.nregions * sizeof *m->regions, GFP_KERNEL); | |
602 | if (!newmem) | |
603 | return -ENOMEM; | |
604 | ||
605 | memcpy(newmem, &mem, size); | |
7ad9c9d2 TY |
606 | if (copy_from_user(newmem->regions, m->regions, |
607 | mem.nregions * sizeof *m->regions)) { | |
3a4d5c94 | 608 | kfree(newmem); |
7ad9c9d2 | 609 | return -EFAULT; |
3a4d5c94 MT |
610 | } |
611 | ||
d47effe1 KK |
612 | if (!memory_access_ok(d, newmem, |
613 | vhost_has_feature(d, VHOST_F_LOG_ALL))) { | |
a02c3789 | 614 | kfree(newmem); |
3a4d5c94 | 615 | return -EFAULT; |
a02c3789 | 616 | } |
28457ee6 AB |
617 | oldmem = rcu_dereference_protected(d->memory, |
618 | lockdep_is_held(&d->mutex)); | |
3a4d5c94 MT |
619 | rcu_assign_pointer(d->memory, newmem); |
620 | synchronize_rcu(); | |
621 | kfree(oldmem); | |
622 | return 0; | |
623 | } | |
624 | ||
935cdee7 | 625 | long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp) |
3a4d5c94 | 626 | { |
cecb46f1 AV |
627 | struct file *eventfp, *filep = NULL; |
628 | bool pollstart = false, pollstop = false; | |
3a4d5c94 MT |
629 | struct eventfd_ctx *ctx = NULL; |
630 | u32 __user *idxp = argp; | |
631 | struct vhost_virtqueue *vq; | |
632 | struct vhost_vring_state s; | |
633 | struct vhost_vring_file f; | |
634 | struct vhost_vring_addr a; | |
635 | u32 idx; | |
636 | long r; | |
637 | ||
638 | r = get_user(idx, idxp); | |
639 | if (r < 0) | |
640 | return r; | |
0f3d9a17 | 641 | if (idx >= d->nvqs) |
3a4d5c94 MT |
642 | return -ENOBUFS; |
643 | ||
644 | vq = d->vqs + idx; | |
645 | ||
646 | mutex_lock(&vq->mutex); | |
647 | ||
648 | switch (ioctl) { | |
649 | case VHOST_SET_VRING_NUM: | |
650 | /* Resizing ring with an active backend? | |
651 | * You don't want to do that. */ | |
652 | if (vq->private_data) { | |
653 | r = -EBUSY; | |
654 | break; | |
655 | } | |
7ad9c9d2 TY |
656 | if (copy_from_user(&s, argp, sizeof s)) { |
657 | r = -EFAULT; | |
3a4d5c94 | 658 | break; |
7ad9c9d2 | 659 | } |
3a4d5c94 MT |
660 | if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) { |
661 | r = -EINVAL; | |
662 | break; | |
663 | } | |
664 | vq->num = s.num; | |
665 | break; | |
666 | case VHOST_SET_VRING_BASE: | |
667 | /* Moving base with an active backend? | |
668 | * You don't want to do that. */ | |
669 | if (vq->private_data) { | |
670 | r = -EBUSY; | |
671 | break; | |
672 | } | |
7ad9c9d2 TY |
673 | if (copy_from_user(&s, argp, sizeof s)) { |
674 | r = -EFAULT; | |
3a4d5c94 | 675 | break; |
7ad9c9d2 | 676 | } |
3a4d5c94 MT |
677 | if (s.num > 0xffff) { |
678 | r = -EINVAL; | |
679 | break; | |
680 | } | |
681 | vq->last_avail_idx = s.num; | |
682 | /* Forget the cached index value. */ | |
683 | vq->avail_idx = vq->last_avail_idx; | |
684 | break; | |
685 | case VHOST_GET_VRING_BASE: | |
686 | s.index = idx; | |
687 | s.num = vq->last_avail_idx; | |
7ad9c9d2 TY |
688 | if (copy_to_user(argp, &s, sizeof s)) |
689 | r = -EFAULT; | |
3a4d5c94 MT |
690 | break; |
691 | case VHOST_SET_VRING_ADDR: | |
7ad9c9d2 TY |
692 | if (copy_from_user(&a, argp, sizeof a)) { |
693 | r = -EFAULT; | |
3a4d5c94 | 694 | break; |
7ad9c9d2 | 695 | } |
3a4d5c94 MT |
696 | if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) { |
697 | r = -EOPNOTSUPP; | |
698 | break; | |
699 | } | |
700 | /* For 32bit, verify that the top 32bits of the user | |
701 | data are set to zero. */ | |
702 | if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr || | |
703 | (u64)(unsigned long)a.used_user_addr != a.used_user_addr || | |
704 | (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) { | |
705 | r = -EFAULT; | |
706 | break; | |
707 | } | |
708 | if ((a.avail_user_addr & (sizeof *vq->avail->ring - 1)) || | |
709 | (a.used_user_addr & (sizeof *vq->used->ring - 1)) || | |
710 | (a.log_guest_addr & (sizeof *vq->used->ring - 1))) { | |
711 | r = -EINVAL; | |
712 | break; | |
713 | } | |
714 | ||
715 | /* We only verify access here if backend is configured. | |
716 | * If it is not, we don't as size might not have been setup. | |
717 | * We will verify when backend is configured. */ | |
718 | if (vq->private_data) { | |
8ea8cf89 | 719 | if (!vq_access_ok(d, vq->num, |
3a4d5c94 MT |
720 | (void __user *)(unsigned long)a.desc_user_addr, |
721 | (void __user *)(unsigned long)a.avail_user_addr, | |
722 | (void __user *)(unsigned long)a.used_user_addr)) { | |
723 | r = -EINVAL; | |
724 | break; | |
725 | } | |
726 | ||
727 | /* Also validate log access for used ring if enabled. */ | |
728 | if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) && | |
729 | !log_access_ok(vq->log_base, a.log_guest_addr, | |
730 | sizeof *vq->used + | |
731 | vq->num * sizeof *vq->used->ring)) { | |
732 | r = -EINVAL; | |
733 | break; | |
734 | } | |
735 | } | |
736 | ||
3a4d5c94 MT |
737 | vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG)); |
738 | vq->desc = (void __user *)(unsigned long)a.desc_user_addr; | |
739 | vq->avail = (void __user *)(unsigned long)a.avail_user_addr; | |
740 | vq->log_addr = a.log_guest_addr; | |
741 | vq->used = (void __user *)(unsigned long)a.used_user_addr; | |
742 | break; | |
743 | case VHOST_SET_VRING_KICK: | |
7ad9c9d2 TY |
744 | if (copy_from_user(&f, argp, sizeof f)) { |
745 | r = -EFAULT; | |
3a4d5c94 | 746 | break; |
7ad9c9d2 | 747 | } |
3a4d5c94 | 748 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
749 | if (IS_ERR(eventfp)) { |
750 | r = PTR_ERR(eventfp); | |
751 | break; | |
752 | } | |
3a4d5c94 | 753 | if (eventfp != vq->kick) { |
cecb46f1 AV |
754 | pollstop = (filep = vq->kick) != NULL; |
755 | pollstart = (vq->kick = eventfp) != NULL; | |
3a4d5c94 MT |
756 | } else |
757 | filep = eventfp; | |
758 | break; | |
759 | case VHOST_SET_VRING_CALL: | |
7ad9c9d2 TY |
760 | if (copy_from_user(&f, argp, sizeof f)) { |
761 | r = -EFAULT; | |
3a4d5c94 | 762 | break; |
7ad9c9d2 | 763 | } |
3a4d5c94 | 764 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
765 | if (IS_ERR(eventfp)) { |
766 | r = PTR_ERR(eventfp); | |
767 | break; | |
768 | } | |
3a4d5c94 MT |
769 | if (eventfp != vq->call) { |
770 | filep = vq->call; | |
771 | ctx = vq->call_ctx; | |
772 | vq->call = eventfp; | |
773 | vq->call_ctx = eventfp ? | |
774 | eventfd_ctx_fileget(eventfp) : NULL; | |
775 | } else | |
776 | filep = eventfp; | |
777 | break; | |
778 | case VHOST_SET_VRING_ERR: | |
7ad9c9d2 TY |
779 | if (copy_from_user(&f, argp, sizeof f)) { |
780 | r = -EFAULT; | |
3a4d5c94 | 781 | break; |
7ad9c9d2 | 782 | } |
3a4d5c94 | 783 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
784 | if (IS_ERR(eventfp)) { |
785 | r = PTR_ERR(eventfp); | |
786 | break; | |
787 | } | |
3a4d5c94 MT |
788 | if (eventfp != vq->error) { |
789 | filep = vq->error; | |
790 | vq->error = eventfp; | |
791 | ctx = vq->error_ctx; | |
792 | vq->error_ctx = eventfp ? | |
793 | eventfd_ctx_fileget(eventfp) : NULL; | |
794 | } else | |
795 | filep = eventfp; | |
796 | break; | |
797 | default: | |
798 | r = -ENOIOCTLCMD; | |
799 | } | |
800 | ||
801 | if (pollstop && vq->handle_kick) | |
802 | vhost_poll_stop(&vq->poll); | |
803 | ||
804 | if (ctx) | |
805 | eventfd_ctx_put(ctx); | |
806 | if (filep) | |
807 | fput(filep); | |
808 | ||
809 | if (pollstart && vq->handle_kick) | |
2b8b328b | 810 | r = vhost_poll_start(&vq->poll, vq->kick); |
3a4d5c94 MT |
811 | |
812 | mutex_unlock(&vq->mutex); | |
813 | ||
814 | if (pollstop && vq->handle_kick) | |
815 | vhost_poll_flush(&vq->poll); | |
816 | return r; | |
817 | } | |
818 | ||
819 | /* Caller must have device mutex */ | |
935cdee7 | 820 | long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp) |
3a4d5c94 | 821 | { |
3a4d5c94 MT |
822 | struct file *eventfp, *filep = NULL; |
823 | struct eventfd_ctx *ctx = NULL; | |
824 | u64 p; | |
825 | long r; | |
826 | int i, fd; | |
827 | ||
828 | /* If you are not the owner, you can become one */ | |
829 | if (ioctl == VHOST_SET_OWNER) { | |
830 | r = vhost_dev_set_owner(d); | |
831 | goto done; | |
832 | } | |
833 | ||
834 | /* You must be the owner to do anything else */ | |
835 | r = vhost_dev_check_owner(d); | |
836 | if (r) | |
837 | goto done; | |
838 | ||
839 | switch (ioctl) { | |
840 | case VHOST_SET_MEM_TABLE: | |
841 | r = vhost_set_memory(d, argp); | |
842 | break; | |
843 | case VHOST_SET_LOG_BASE: | |
7ad9c9d2 TY |
844 | if (copy_from_user(&p, argp, sizeof p)) { |
845 | r = -EFAULT; | |
3a4d5c94 | 846 | break; |
7ad9c9d2 | 847 | } |
3a4d5c94 MT |
848 | if ((u64)(unsigned long)p != p) { |
849 | r = -EFAULT; | |
850 | break; | |
851 | } | |
852 | for (i = 0; i < d->nvqs; ++i) { | |
853 | struct vhost_virtqueue *vq; | |
854 | void __user *base = (void __user *)(unsigned long)p; | |
855 | vq = d->vqs + i; | |
856 | mutex_lock(&vq->mutex); | |
857 | /* If ring is inactive, will check when it's enabled. */ | |
8ea8cf89 | 858 | if (vq->private_data && !vq_log_access_ok(d, vq, base)) |
3a4d5c94 MT |
859 | r = -EFAULT; |
860 | else | |
861 | vq->log_base = base; | |
862 | mutex_unlock(&vq->mutex); | |
863 | } | |
864 | break; | |
865 | case VHOST_SET_LOG_FD: | |
866 | r = get_user(fd, (int __user *)argp); | |
867 | if (r < 0) | |
868 | break; | |
869 | eventfp = fd == -1 ? NULL : eventfd_fget(fd); | |
870 | if (IS_ERR(eventfp)) { | |
871 | r = PTR_ERR(eventfp); | |
872 | break; | |
873 | } | |
874 | if (eventfp != d->log_file) { | |
875 | filep = d->log_file; | |
876 | ctx = d->log_ctx; | |
877 | d->log_ctx = eventfp ? | |
878 | eventfd_ctx_fileget(eventfp) : NULL; | |
879 | } else | |
880 | filep = eventfp; | |
881 | for (i = 0; i < d->nvqs; ++i) { | |
882 | mutex_lock(&d->vqs[i].mutex); | |
883 | d->vqs[i].log_ctx = d->log_ctx; | |
884 | mutex_unlock(&d->vqs[i].mutex); | |
885 | } | |
886 | if (ctx) | |
887 | eventfd_ctx_put(ctx); | |
888 | if (filep) | |
889 | fput(filep); | |
890 | break; | |
891 | default: | |
935cdee7 | 892 | r = -ENOIOCTLCMD; |
3a4d5c94 MT |
893 | break; |
894 | } | |
895 | done: | |
896 | return r; | |
897 | } | |
898 | ||
899 | static const struct vhost_memory_region *find_region(struct vhost_memory *mem, | |
900 | __u64 addr, __u32 len) | |
901 | { | |
902 | struct vhost_memory_region *reg; | |
903 | int i; | |
d47effe1 | 904 | |
3a4d5c94 MT |
905 | /* linear search is not brilliant, but we really have on the order of 6 |
906 | * regions in practice */ | |
907 | for (i = 0; i < mem->nregions; ++i) { | |
908 | reg = mem->regions + i; | |
909 | if (reg->guest_phys_addr <= addr && | |
910 | reg->guest_phys_addr + reg->memory_size - 1 >= addr) | |
911 | return reg; | |
912 | } | |
913 | return NULL; | |
914 | } | |
915 | ||
916 | /* TODO: This is really inefficient. We need something like get_user() | |
917 | * (instruction directly accesses the data, with an exception table entry | |
918 | * returning -EFAULT). See Documentation/x86/exception-tables.txt. | |
919 | */ | |
920 | static int set_bit_to_user(int nr, void __user *addr) | |
921 | { | |
922 | unsigned long log = (unsigned long)addr; | |
923 | struct page *page; | |
924 | void *base; | |
925 | int bit = nr + (log % PAGE_SIZE) * 8; | |
926 | int r; | |
d47effe1 | 927 | |
3a4d5c94 | 928 | r = get_user_pages_fast(log, 1, 1, &page); |
d6db3f5c | 929 | if (r < 0) |
3a4d5c94 | 930 | return r; |
d6db3f5c | 931 | BUG_ON(r != 1); |
c6daa7ff | 932 | base = kmap_atomic(page); |
3a4d5c94 | 933 | set_bit(bit, base); |
c6daa7ff | 934 | kunmap_atomic(base); |
3a4d5c94 MT |
935 | set_page_dirty_lock(page); |
936 | put_page(page); | |
937 | return 0; | |
938 | } | |
939 | ||
940 | static int log_write(void __user *log_base, | |
941 | u64 write_address, u64 write_length) | |
942 | { | |
28831ee6 | 943 | u64 write_page = write_address / VHOST_PAGE_SIZE; |
3a4d5c94 | 944 | int r; |
d47effe1 | 945 | |
3a4d5c94 MT |
946 | if (!write_length) |
947 | return 0; | |
3bf9be40 | 948 | write_length += write_address % VHOST_PAGE_SIZE; |
3a4d5c94 MT |
949 | for (;;) { |
950 | u64 base = (u64)(unsigned long)log_base; | |
28831ee6 MT |
951 | u64 log = base + write_page / 8; |
952 | int bit = write_page % 8; | |
3a4d5c94 MT |
953 | if ((u64)(unsigned long)log != log) |
954 | return -EFAULT; | |
955 | r = set_bit_to_user(bit, (void __user *)(unsigned long)log); | |
956 | if (r < 0) | |
957 | return r; | |
958 | if (write_length <= VHOST_PAGE_SIZE) | |
959 | break; | |
960 | write_length -= VHOST_PAGE_SIZE; | |
28831ee6 | 961 | write_page += 1; |
3a4d5c94 MT |
962 | } |
963 | return r; | |
964 | } | |
965 | ||
966 | int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, | |
967 | unsigned int log_num, u64 len) | |
968 | { | |
969 | int i, r; | |
970 | ||
971 | /* Make sure data written is seen before log. */ | |
5659338c | 972 | smp_wmb(); |
3a4d5c94 MT |
973 | for (i = 0; i < log_num; ++i) { |
974 | u64 l = min(log[i].len, len); | |
975 | r = log_write(vq->log_base, log[i].addr, l); | |
976 | if (r < 0) | |
977 | return r; | |
978 | len -= l; | |
5786aee8 MT |
979 | if (!len) { |
980 | if (vq->log_ctx) | |
981 | eventfd_signal(vq->log_ctx, 1); | |
3a4d5c94 | 982 | return 0; |
5786aee8 | 983 | } |
3a4d5c94 | 984 | } |
3a4d5c94 MT |
985 | /* Length written exceeds what we have stored. This is a bug. */ |
986 | BUG(); | |
987 | return 0; | |
988 | } | |
989 | ||
2723feaa JW |
990 | static int vhost_update_used_flags(struct vhost_virtqueue *vq) |
991 | { | |
992 | void __user *used; | |
b834226b | 993 | if (__put_user(vq->used_flags, &vq->used->flags) < 0) |
2723feaa JW |
994 | return -EFAULT; |
995 | if (unlikely(vq->log_used)) { | |
996 | /* Make sure the flag is seen before log. */ | |
997 | smp_wmb(); | |
998 | /* Log used flag write. */ | |
999 | used = &vq->used->flags; | |
1000 | log_write(vq->log_base, vq->log_addr + | |
1001 | (used - (void __user *)vq->used), | |
1002 | sizeof vq->used->flags); | |
1003 | if (vq->log_ctx) | |
1004 | eventfd_signal(vq->log_ctx, 1); | |
1005 | } | |
1006 | return 0; | |
1007 | } | |
1008 | ||
1009 | static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event) | |
1010 | { | |
b834226b | 1011 | if (__put_user(vq->avail_idx, vhost_avail_event(vq))) |
2723feaa JW |
1012 | return -EFAULT; |
1013 | if (unlikely(vq->log_used)) { | |
1014 | void __user *used; | |
1015 | /* Make sure the event is seen before log. */ | |
1016 | smp_wmb(); | |
1017 | /* Log avail event write */ | |
1018 | used = vhost_avail_event(vq); | |
1019 | log_write(vq->log_base, vq->log_addr + | |
1020 | (used - (void __user *)vq->used), | |
1021 | sizeof *vhost_avail_event(vq)); | |
1022 | if (vq->log_ctx) | |
1023 | eventfd_signal(vq->log_ctx, 1); | |
1024 | } | |
1025 | return 0; | |
1026 | } | |
1027 | ||
1028 | int vhost_init_used(struct vhost_virtqueue *vq) | |
1029 | { | |
1030 | int r; | |
1031 | if (!vq->private_data) | |
1032 | return 0; | |
1033 | ||
1034 | r = vhost_update_used_flags(vq); | |
1035 | if (r) | |
1036 | return r; | |
1037 | vq->signalled_used_valid = false; | |
1038 | return get_user(vq->last_used_idx, &vq->used->idx); | |
1039 | } | |
1040 | ||
a8d3782f CH |
1041 | static int translate_desc(struct vhost_dev *dev, u64 addr, u32 len, |
1042 | struct iovec iov[], int iov_size) | |
3a4d5c94 MT |
1043 | { |
1044 | const struct vhost_memory_region *reg; | |
1045 | struct vhost_memory *mem; | |
1046 | struct iovec *_iov; | |
1047 | u64 s = 0; | |
1048 | int ret = 0; | |
1049 | ||
1050 | rcu_read_lock(); | |
1051 | ||
1052 | mem = rcu_dereference(dev->memory); | |
1053 | while ((u64)len > s) { | |
1054 | u64 size; | |
7b3384fc | 1055 | if (unlikely(ret >= iov_size)) { |
3a4d5c94 MT |
1056 | ret = -ENOBUFS; |
1057 | break; | |
1058 | } | |
1059 | reg = find_region(mem, addr, len); | |
7b3384fc | 1060 | if (unlikely(!reg)) { |
3a4d5c94 MT |
1061 | ret = -EFAULT; |
1062 | break; | |
1063 | } | |
1064 | _iov = iov + ret; | |
1065 | size = reg->memory_size - addr + reg->guest_phys_addr; | |
bd97120f | 1066 | _iov->iov_len = min((u64)len - s, size); |
a8d3782f | 1067 | _iov->iov_base = (void __user *)(unsigned long) |
3a4d5c94 MT |
1068 | (reg->userspace_addr + addr - reg->guest_phys_addr); |
1069 | s += size; | |
1070 | addr += size; | |
1071 | ++ret; | |
1072 | } | |
1073 | ||
1074 | rcu_read_unlock(); | |
1075 | return ret; | |
1076 | } | |
1077 | ||
1078 | /* Each buffer in the virtqueues is actually a chain of descriptors. This | |
1079 | * function returns the next descriptor in the chain, | |
1080 | * or -1U if we're at the end. */ | |
1081 | static unsigned next_desc(struct vring_desc *desc) | |
1082 | { | |
1083 | unsigned int next; | |
1084 | ||
1085 | /* If this descriptor says it doesn't chain, we're done. */ | |
1086 | if (!(desc->flags & VRING_DESC_F_NEXT)) | |
1087 | return -1U; | |
1088 | ||
1089 | /* Check they're not leading us off end of descriptors. */ | |
1090 | next = desc->next; | |
1091 | /* Make sure compiler knows to grab that: we don't want it changing! */ | |
1092 | /* We will use the result as an index in an array, so most | |
1093 | * architectures only need a compiler barrier here. */ | |
1094 | read_barrier_depends(); | |
1095 | ||
1096 | return next; | |
1097 | } | |
1098 | ||
7b3384fc MT |
1099 | static int get_indirect(struct vhost_dev *dev, struct vhost_virtqueue *vq, |
1100 | struct iovec iov[], unsigned int iov_size, | |
1101 | unsigned int *out_num, unsigned int *in_num, | |
1102 | struct vhost_log *log, unsigned int *log_num, | |
1103 | struct vring_desc *indirect) | |
3a4d5c94 MT |
1104 | { |
1105 | struct vring_desc desc; | |
1106 | unsigned int i = 0, count, found = 0; | |
1107 | int ret; | |
1108 | ||
1109 | /* Sanity check */ | |
7b3384fc | 1110 | if (unlikely(indirect->len % sizeof desc)) { |
3a4d5c94 MT |
1111 | vq_err(vq, "Invalid length in indirect descriptor: " |
1112 | "len 0x%llx not multiple of 0x%zx\n", | |
1113 | (unsigned long long)indirect->len, | |
1114 | sizeof desc); | |
1115 | return -EINVAL; | |
1116 | } | |
1117 | ||
1118 | ret = translate_desc(dev, indirect->addr, indirect->len, vq->indirect, | |
e0e9b406 | 1119 | UIO_MAXIOV); |
7b3384fc | 1120 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1121 | vq_err(vq, "Translation failure %d in indirect.\n", ret); |
1122 | return ret; | |
1123 | } | |
1124 | ||
1125 | /* We will use the result as an address to read from, so most | |
1126 | * architectures only need a compiler barrier here. */ | |
1127 | read_barrier_depends(); | |
1128 | ||
1129 | count = indirect->len / sizeof desc; | |
1130 | /* Buffers are chained via a 16 bit next field, so | |
1131 | * we can have at most 2^16 of these. */ | |
7b3384fc | 1132 | if (unlikely(count > USHRT_MAX + 1)) { |
3a4d5c94 MT |
1133 | vq_err(vq, "Indirect buffer length too big: %d\n", |
1134 | indirect->len); | |
1135 | return -E2BIG; | |
1136 | } | |
1137 | ||
1138 | do { | |
1139 | unsigned iov_count = *in_num + *out_num; | |
7b3384fc | 1140 | if (unlikely(++found > count)) { |
3a4d5c94 MT |
1141 | vq_err(vq, "Loop detected: last one at %u " |
1142 | "indirect size %u\n", | |
1143 | i, count); | |
1144 | return -EINVAL; | |
1145 | } | |
d47effe1 KK |
1146 | if (unlikely(memcpy_fromiovec((unsigned char *)&desc, |
1147 | vq->indirect, sizeof desc))) { | |
3a4d5c94 MT |
1148 | vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n", |
1149 | i, (size_t)indirect->addr + i * sizeof desc); | |
1150 | return -EINVAL; | |
1151 | } | |
7b3384fc | 1152 | if (unlikely(desc.flags & VRING_DESC_F_INDIRECT)) { |
3a4d5c94 MT |
1153 | vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n", |
1154 | i, (size_t)indirect->addr + i * sizeof desc); | |
1155 | return -EINVAL; | |
1156 | } | |
1157 | ||
1158 | ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, | |
1159 | iov_size - iov_count); | |
7b3384fc | 1160 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1161 | vq_err(vq, "Translation failure %d indirect idx %d\n", |
1162 | ret, i); | |
1163 | return ret; | |
1164 | } | |
1165 | /* If this is an input descriptor, increment that count. */ | |
1166 | if (desc.flags & VRING_DESC_F_WRITE) { | |
1167 | *in_num += ret; | |
1168 | if (unlikely(log)) { | |
1169 | log[*log_num].addr = desc.addr; | |
1170 | log[*log_num].len = desc.len; | |
1171 | ++*log_num; | |
1172 | } | |
1173 | } else { | |
1174 | /* If it's an output descriptor, they're all supposed | |
1175 | * to come before any input descriptors. */ | |
7b3384fc | 1176 | if (unlikely(*in_num)) { |
3a4d5c94 MT |
1177 | vq_err(vq, "Indirect descriptor " |
1178 | "has out after in: idx %d\n", i); | |
1179 | return -EINVAL; | |
1180 | } | |
1181 | *out_num += ret; | |
1182 | } | |
1183 | } while ((i = next_desc(&desc)) != -1); | |
1184 | return 0; | |
1185 | } | |
1186 | ||
1187 | /* This looks in the virtqueue and for the first available buffer, and converts | |
1188 | * it to an iovec for convenient access. Since descriptors consist of some | |
1189 | * number of output then some number of input descriptors, it's actually two | |
1190 | * iovecs, but we pack them into one and note how many of each there were. | |
1191 | * | |
d5675bd2 MT |
1192 | * This function returns the descriptor number found, or vq->num (which is |
1193 | * never a valid descriptor number) if none was found. A negative code is | |
1194 | * returned on error. */ | |
1195 | int vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq, | |
1196 | struct iovec iov[], unsigned int iov_size, | |
1197 | unsigned int *out_num, unsigned int *in_num, | |
1198 | struct vhost_log *log, unsigned int *log_num) | |
3a4d5c94 MT |
1199 | { |
1200 | struct vring_desc desc; | |
1201 | unsigned int i, head, found = 0; | |
1202 | u16 last_avail_idx; | |
1203 | int ret; | |
1204 | ||
1205 | /* Check it isn't doing very strange things with descriptor numbers. */ | |
1206 | last_avail_idx = vq->last_avail_idx; | |
8b7347aa | 1207 | if (unlikely(__get_user(vq->avail_idx, &vq->avail->idx))) { |
3a4d5c94 MT |
1208 | vq_err(vq, "Failed to access avail idx at %p\n", |
1209 | &vq->avail->idx); | |
d5675bd2 | 1210 | return -EFAULT; |
3a4d5c94 MT |
1211 | } |
1212 | ||
7b3384fc | 1213 | if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) { |
3a4d5c94 MT |
1214 | vq_err(vq, "Guest moved used index from %u to %u", |
1215 | last_avail_idx, vq->avail_idx); | |
d5675bd2 | 1216 | return -EFAULT; |
3a4d5c94 MT |
1217 | } |
1218 | ||
1219 | /* If there's nothing new since last we looked, return invalid. */ | |
1220 | if (vq->avail_idx == last_avail_idx) | |
1221 | return vq->num; | |
1222 | ||
1223 | /* Only get avail ring entries after they have been exposed by guest. */ | |
5659338c | 1224 | smp_rmb(); |
3a4d5c94 MT |
1225 | |
1226 | /* Grab the next descriptor number they're advertising, and increment | |
1227 | * the index we've seen. */ | |
8b7347aa MT |
1228 | if (unlikely(__get_user(head, |
1229 | &vq->avail->ring[last_avail_idx % vq->num]))) { | |
3a4d5c94 MT |
1230 | vq_err(vq, "Failed to read head: idx %d address %p\n", |
1231 | last_avail_idx, | |
1232 | &vq->avail->ring[last_avail_idx % vq->num]); | |
d5675bd2 | 1233 | return -EFAULT; |
3a4d5c94 MT |
1234 | } |
1235 | ||
1236 | /* If their number is silly, that's an error. */ | |
7b3384fc | 1237 | if (unlikely(head >= vq->num)) { |
3a4d5c94 MT |
1238 | vq_err(vq, "Guest says index %u > %u is available", |
1239 | head, vq->num); | |
d5675bd2 | 1240 | return -EINVAL; |
3a4d5c94 MT |
1241 | } |
1242 | ||
1243 | /* When we start there are none of either input nor output. */ | |
1244 | *out_num = *in_num = 0; | |
1245 | if (unlikely(log)) | |
1246 | *log_num = 0; | |
1247 | ||
1248 | i = head; | |
1249 | do { | |
1250 | unsigned iov_count = *in_num + *out_num; | |
7b3384fc | 1251 | if (unlikely(i >= vq->num)) { |
3a4d5c94 MT |
1252 | vq_err(vq, "Desc index is %u > %u, head = %u", |
1253 | i, vq->num, head); | |
d5675bd2 | 1254 | return -EINVAL; |
3a4d5c94 | 1255 | } |
7b3384fc | 1256 | if (unlikely(++found > vq->num)) { |
3a4d5c94 MT |
1257 | vq_err(vq, "Loop detected: last one at %u " |
1258 | "vq size %u head %u\n", | |
1259 | i, vq->num, head); | |
d5675bd2 | 1260 | return -EINVAL; |
3a4d5c94 | 1261 | } |
fcc042a2 | 1262 | ret = __copy_from_user(&desc, vq->desc + i, sizeof desc); |
7b3384fc | 1263 | if (unlikely(ret)) { |
3a4d5c94 MT |
1264 | vq_err(vq, "Failed to get descriptor: idx %d addr %p\n", |
1265 | i, vq->desc + i); | |
d5675bd2 | 1266 | return -EFAULT; |
3a4d5c94 MT |
1267 | } |
1268 | if (desc.flags & VRING_DESC_F_INDIRECT) { | |
1269 | ret = get_indirect(dev, vq, iov, iov_size, | |
1270 | out_num, in_num, | |
1271 | log, log_num, &desc); | |
7b3384fc | 1272 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1273 | vq_err(vq, "Failure detected " |
1274 | "in indirect descriptor at idx %d\n", i); | |
d5675bd2 | 1275 | return ret; |
3a4d5c94 MT |
1276 | } |
1277 | continue; | |
1278 | } | |
1279 | ||
1280 | ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, | |
1281 | iov_size - iov_count); | |
7b3384fc | 1282 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1283 | vq_err(vq, "Translation failure %d descriptor idx %d\n", |
1284 | ret, i); | |
d5675bd2 | 1285 | return ret; |
3a4d5c94 MT |
1286 | } |
1287 | if (desc.flags & VRING_DESC_F_WRITE) { | |
1288 | /* If this is an input descriptor, | |
1289 | * increment that count. */ | |
1290 | *in_num += ret; | |
1291 | if (unlikely(log)) { | |
1292 | log[*log_num].addr = desc.addr; | |
1293 | log[*log_num].len = desc.len; | |
1294 | ++*log_num; | |
1295 | } | |
1296 | } else { | |
1297 | /* If it's an output descriptor, they're all supposed | |
1298 | * to come before any input descriptors. */ | |
7b3384fc | 1299 | if (unlikely(*in_num)) { |
3a4d5c94 MT |
1300 | vq_err(vq, "Descriptor has out after in: " |
1301 | "idx %d\n", i); | |
d5675bd2 | 1302 | return -EINVAL; |
3a4d5c94 MT |
1303 | } |
1304 | *out_num += ret; | |
1305 | } | |
1306 | } while ((i = next_desc(&desc)) != -1); | |
1307 | ||
1308 | /* On success, increment avail index. */ | |
1309 | vq->last_avail_idx++; | |
8ea8cf89 MT |
1310 | |
1311 | /* Assume notifications from guest are disabled at this point, | |
1312 | * if they aren't we would need to update avail_event index. */ | |
1313 | BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY)); | |
3a4d5c94 MT |
1314 | return head; |
1315 | } | |
1316 | ||
1317 | /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */ | |
8dd014ad | 1318 | void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n) |
3a4d5c94 | 1319 | { |
8dd014ad | 1320 | vq->last_avail_idx -= n; |
3a4d5c94 MT |
1321 | } |
1322 | ||
1323 | /* After we've used one of their buffers, we tell them about it. We'll then | |
1324 | * want to notify the guest, using eventfd. */ | |
1325 | int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len) | |
1326 | { | |
a8d3782f | 1327 | struct vring_used_elem __user *used; |
3a4d5c94 MT |
1328 | |
1329 | /* The virtqueue contains a ring of used buffers. Get a pointer to the | |
1330 | * next entry in that used ring. */ | |
1331 | used = &vq->used->ring[vq->last_used_idx % vq->num]; | |
8b7347aa | 1332 | if (__put_user(head, &used->id)) { |
3a4d5c94 MT |
1333 | vq_err(vq, "Failed to write used id"); |
1334 | return -EFAULT; | |
1335 | } | |
8b7347aa | 1336 | if (__put_user(len, &used->len)) { |
3a4d5c94 MT |
1337 | vq_err(vq, "Failed to write used len"); |
1338 | return -EFAULT; | |
1339 | } | |
1340 | /* Make sure buffer is written before we update index. */ | |
5659338c | 1341 | smp_wmb(); |
8b7347aa | 1342 | if (__put_user(vq->last_used_idx + 1, &vq->used->idx)) { |
3a4d5c94 MT |
1343 | vq_err(vq, "Failed to increment used idx"); |
1344 | return -EFAULT; | |
1345 | } | |
1346 | if (unlikely(vq->log_used)) { | |
1347 | /* Make sure data is seen before log. */ | |
5659338c | 1348 | smp_wmb(); |
86e9424d MT |
1349 | /* Log used ring entry write. */ |
1350 | log_write(vq->log_base, | |
a8d3782f CH |
1351 | vq->log_addr + |
1352 | ((void __user *)used - (void __user *)vq->used), | |
86e9424d MT |
1353 | sizeof *used); |
1354 | /* Log used index update. */ | |
1355 | log_write(vq->log_base, | |
1356 | vq->log_addr + offsetof(struct vring_used, idx), | |
1357 | sizeof vq->used->idx); | |
3a4d5c94 MT |
1358 | if (vq->log_ctx) |
1359 | eventfd_signal(vq->log_ctx, 1); | |
1360 | } | |
1361 | vq->last_used_idx++; | |
8ea8cf89 MT |
1362 | /* If the driver never bothers to signal in a very long while, |
1363 | * used index might wrap around. If that happens, invalidate | |
1364 | * signalled_used index we stored. TODO: make sure driver | |
1365 | * signals at least once in 2^16 and remove this. */ | |
1366 | if (unlikely(vq->last_used_idx == vq->signalled_used)) | |
1367 | vq->signalled_used_valid = false; | |
3a4d5c94 MT |
1368 | return 0; |
1369 | } | |
1370 | ||
8dd014ad DS |
1371 | static int __vhost_add_used_n(struct vhost_virtqueue *vq, |
1372 | struct vring_used_elem *heads, | |
1373 | unsigned count) | |
1374 | { | |
1375 | struct vring_used_elem __user *used; | |
8ea8cf89 | 1376 | u16 old, new; |
8dd014ad DS |
1377 | int start; |
1378 | ||
1379 | start = vq->last_used_idx % vq->num; | |
1380 | used = vq->used->ring + start; | |
dfe5ac5b | 1381 | if (__copy_to_user(used, heads, count * sizeof *used)) { |
8dd014ad DS |
1382 | vq_err(vq, "Failed to write used"); |
1383 | return -EFAULT; | |
1384 | } | |
1385 | if (unlikely(vq->log_used)) { | |
1386 | /* Make sure data is seen before log. */ | |
1387 | smp_wmb(); | |
1388 | /* Log used ring entry write. */ | |
1389 | log_write(vq->log_base, | |
1390 | vq->log_addr + | |
1391 | ((void __user *)used - (void __user *)vq->used), | |
1392 | count * sizeof *used); | |
1393 | } | |
8ea8cf89 MT |
1394 | old = vq->last_used_idx; |
1395 | new = (vq->last_used_idx += count); | |
1396 | /* If the driver never bothers to signal in a very long while, | |
1397 | * used index might wrap around. If that happens, invalidate | |
1398 | * signalled_used index we stored. TODO: make sure driver | |
1399 | * signals at least once in 2^16 and remove this. */ | |
1400 | if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old))) | |
1401 | vq->signalled_used_valid = false; | |
8dd014ad DS |
1402 | return 0; |
1403 | } | |
1404 | ||
1405 | /* After we've used one of their buffers, we tell them about it. We'll then | |
1406 | * want to notify the guest, using eventfd. */ | |
1407 | int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads, | |
1408 | unsigned count) | |
1409 | { | |
1410 | int start, n, r; | |
1411 | ||
1412 | start = vq->last_used_idx % vq->num; | |
1413 | n = vq->num - start; | |
1414 | if (n < count) { | |
1415 | r = __vhost_add_used_n(vq, heads, n); | |
1416 | if (r < 0) | |
1417 | return r; | |
1418 | heads += n; | |
1419 | count -= n; | |
1420 | } | |
1421 | r = __vhost_add_used_n(vq, heads, count); | |
1422 | ||
1423 | /* Make sure buffer is written before we update index. */ | |
1424 | smp_wmb(); | |
1425 | if (put_user(vq->last_used_idx, &vq->used->idx)) { | |
1426 | vq_err(vq, "Failed to increment used idx"); | |
1427 | return -EFAULT; | |
1428 | } | |
1429 | if (unlikely(vq->log_used)) { | |
1430 | /* Log used index update. */ | |
1431 | log_write(vq->log_base, | |
1432 | vq->log_addr + offsetof(struct vring_used, idx), | |
1433 | sizeof vq->used->idx); | |
1434 | if (vq->log_ctx) | |
1435 | eventfd_signal(vq->log_ctx, 1); | |
1436 | } | |
1437 | return r; | |
1438 | } | |
1439 | ||
8ea8cf89 | 1440 | static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
3a4d5c94 | 1441 | { |
8ea8cf89 MT |
1442 | __u16 old, new, event; |
1443 | bool v; | |
0d499356 MT |
1444 | /* Flush out used index updates. This is paired |
1445 | * with the barrier that the Guest executes when enabling | |
1446 | * interrupts. */ | |
1447 | smp_mb(); | |
1448 | ||
8ea8cf89 MT |
1449 | if (vhost_has_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY) && |
1450 | unlikely(vq->avail_idx == vq->last_avail_idx)) | |
1451 | return true; | |
1452 | ||
1453 | if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { | |
1454 | __u16 flags; | |
1455 | if (__get_user(flags, &vq->avail->flags)) { | |
1456 | vq_err(vq, "Failed to get flags"); | |
1457 | return true; | |
1458 | } | |
1459 | return !(flags & VRING_AVAIL_F_NO_INTERRUPT); | |
3a4d5c94 | 1460 | } |
8ea8cf89 MT |
1461 | old = vq->signalled_used; |
1462 | v = vq->signalled_used_valid; | |
1463 | new = vq->signalled_used = vq->last_used_idx; | |
1464 | vq->signalled_used_valid = true; | |
3a4d5c94 | 1465 | |
8ea8cf89 MT |
1466 | if (unlikely(!v)) |
1467 | return true; | |
3a4d5c94 | 1468 | |
8ea8cf89 MT |
1469 | if (get_user(event, vhost_used_event(vq))) { |
1470 | vq_err(vq, "Failed to get used event idx"); | |
1471 | return true; | |
1472 | } | |
1473 | return vring_need_event(event, new, old); | |
1474 | } | |
1475 | ||
1476 | /* This actually signals the guest, using eventfd. */ | |
1477 | void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq) | |
1478 | { | |
3a4d5c94 | 1479 | /* Signal the Guest tell them we used something up. */ |
8ea8cf89 | 1480 | if (vq->call_ctx && vhost_notify(dev, vq)) |
3a4d5c94 MT |
1481 | eventfd_signal(vq->call_ctx, 1); |
1482 | } | |
1483 | ||
1484 | /* And here's the combo meal deal. Supersize me! */ | |
1485 | void vhost_add_used_and_signal(struct vhost_dev *dev, | |
1486 | struct vhost_virtqueue *vq, | |
1487 | unsigned int head, int len) | |
1488 | { | |
1489 | vhost_add_used(vq, head, len); | |
1490 | vhost_signal(dev, vq); | |
1491 | } | |
1492 | ||
8dd014ad DS |
1493 | /* multi-buffer version of vhost_add_used_and_signal */ |
1494 | void vhost_add_used_and_signal_n(struct vhost_dev *dev, | |
1495 | struct vhost_virtqueue *vq, | |
1496 | struct vring_used_elem *heads, unsigned count) | |
1497 | { | |
1498 | vhost_add_used_n(vq, heads, count); | |
1499 | vhost_signal(dev, vq); | |
1500 | } | |
1501 | ||
3a4d5c94 | 1502 | /* OK, now we need to know about added descriptors. */ |
8ea8cf89 | 1503 | bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
3a4d5c94 MT |
1504 | { |
1505 | u16 avail_idx; | |
1506 | int r; | |
d47effe1 | 1507 | |
3a4d5c94 MT |
1508 | if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY)) |
1509 | return false; | |
1510 | vq->used_flags &= ~VRING_USED_F_NO_NOTIFY; | |
8ea8cf89 | 1511 | if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { |
2723feaa | 1512 | r = vhost_update_used_flags(vq); |
8ea8cf89 MT |
1513 | if (r) { |
1514 | vq_err(vq, "Failed to enable notification at %p: %d\n", | |
1515 | &vq->used->flags, r); | |
1516 | return false; | |
1517 | } | |
1518 | } else { | |
2723feaa | 1519 | r = vhost_update_avail_event(vq, vq->avail_idx); |
8ea8cf89 MT |
1520 | if (r) { |
1521 | vq_err(vq, "Failed to update avail event index at %p: %d\n", | |
1522 | vhost_avail_event(vq), r); | |
1523 | return false; | |
1524 | } | |
1525 | } | |
3a4d5c94 MT |
1526 | /* They could have slipped one in as we were doing that: make |
1527 | * sure it's written, then check again. */ | |
5659338c | 1528 | smp_mb(); |
8b7347aa | 1529 | r = __get_user(avail_idx, &vq->avail->idx); |
3a4d5c94 MT |
1530 | if (r) { |
1531 | vq_err(vq, "Failed to check avail idx at %p: %d\n", | |
1532 | &vq->avail->idx, r); | |
1533 | return false; | |
1534 | } | |
1535 | ||
8dd014ad | 1536 | return avail_idx != vq->avail_idx; |
3a4d5c94 MT |
1537 | } |
1538 | ||
1539 | /* We don't need to be notified again. */ | |
8ea8cf89 | 1540 | void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
3a4d5c94 MT |
1541 | { |
1542 | int r; | |
d47effe1 | 1543 | |
3a4d5c94 MT |
1544 | if (vq->used_flags & VRING_USED_F_NO_NOTIFY) |
1545 | return; | |
1546 | vq->used_flags |= VRING_USED_F_NO_NOTIFY; | |
8ea8cf89 | 1547 | if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { |
2723feaa | 1548 | r = vhost_update_used_flags(vq); |
8ea8cf89 MT |
1549 | if (r) |
1550 | vq_err(vq, "Failed to enable notification at %p: %d\n", | |
1551 | &vq->used->flags, r); | |
1552 | } | |
3a4d5c94 | 1553 | } |
bab632d6 MT |
1554 | |
1555 | static void vhost_zerocopy_done_signal(struct kref *kref) | |
1556 | { | |
1557 | struct vhost_ubuf_ref *ubufs = container_of(kref, struct vhost_ubuf_ref, | |
1558 | kref); | |
1559 | wake_up(&ubufs->wait); | |
1560 | } | |
1561 | ||
1562 | struct vhost_ubuf_ref *vhost_ubuf_alloc(struct vhost_virtqueue *vq, | |
1563 | bool zcopy) | |
1564 | { | |
1565 | struct vhost_ubuf_ref *ubufs; | |
1566 | /* No zero copy backend? Nothing to count. */ | |
1567 | if (!zcopy) | |
1568 | return NULL; | |
1569 | ubufs = kmalloc(sizeof *ubufs, GFP_KERNEL); | |
1570 | if (!ubufs) | |
1571 | return ERR_PTR(-ENOMEM); | |
1572 | kref_init(&ubufs->kref); | |
bab632d6 MT |
1573 | init_waitqueue_head(&ubufs->wait); |
1574 | ubufs->vq = vq; | |
1575 | return ubufs; | |
1576 | } | |
1577 | ||
1578 | void vhost_ubuf_put(struct vhost_ubuf_ref *ubufs) | |
1579 | { | |
1580 | kref_put(&ubufs->kref, vhost_zerocopy_done_signal); | |
1581 | } | |
1582 | ||
1583 | void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *ubufs) | |
1584 | { | |
1585 | kref_put(&ubufs->kref, vhost_zerocopy_done_signal); | |
1586 | wait_event(ubufs->wait, !atomic_read(&ubufs->kref.refcount)); | |
1587 | kfree(ubufs); | |
1588 | } |