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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 |
7 | * Documentation/virtual/lguest/lguest.c, by Rusty Russell |
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> |
18 | #include <linux/mmu_context.h> |
19 | #include <linux/miscdevice.h> |
20 | #include <linux/mutex.h> |
21 | #include <linux/rcupdate.h> |
22 | #include <linux/poll.h> |
23 | #include <linux/file.h> |
24 | #include <linux/highmem.h> |
25 | #include <linux/slab.h> |
26 | #include <linux/kthread.h> |
27 | #include <linux/cgroup.h> |
28 | |
29 | #include "vhost.h" |
30 | |
31 | enum { |
32 | VHOST_MEMORY_MAX_NREGIONS = 64, |
33 | VHOST_MEMORY_F_LOG = 0x1, |
34 | }; |
35 | |
36 | static unsigned vhost_zcopy_mask __read_mostly; |
37 | |
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 | |
41 | static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh, |
42 | poll_table *pt) |
43 | { |
44 | struct vhost_poll *poll; |
45 | |
46 | poll = container_of(pt, struct vhost_poll, table); |
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 | { |
54 | struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait); |
55 | |
56 | if (!((unsigned long)key & poll->mask)) |
57 | return 0; |
58 | |
59 | vhost_poll_queue(poll); |
60 | return 0; |
61 | } |
62 | |
63 | void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn) |
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 | |
72 | /* Init poll structure */ |
73 | void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, |
74 | unsigned long mask, struct vhost_dev *dev) |
75 | { |
76 | init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup); |
77 | init_poll_funcptr(&poll->table, vhost_poll_func); |
78 | poll->mask = mask; |
79 | poll->dev = dev; |
80 | poll->wqh = NULL; |
81 | |
82 | vhost_work_init(&poll->work, fn); |
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. */ |
87 | int vhost_poll_start(struct vhost_poll *poll, struct file *file) |
88 | { |
89 | unsigned long mask; |
90 | int ret = 0; |
91 | |
92 | mask = file->f_op->poll(file, &poll->table); |
93 | if (mask) |
94 | vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask); |
95 | if (mask & POLLERR) { |
96 | if (poll->wqh) |
97 | remove_wait_queue(poll->wqh, &poll->wait); |
98 | ret = -EINVAL; |
99 | } |
100 | |
101 | return ret; |
102 | } |
103 | |
104 | /* Stop polling a file. After this function returns, it becomes safe to drop the |
105 | * file reference. You must also flush afterwards. */ |
106 | void vhost_poll_stop(struct vhost_poll *poll) |
107 | { |
108 | if (poll->wqh) { |
109 | remove_wait_queue(poll->wqh, &poll->wait); |
110 | poll->wqh = NULL; |
111 | } |
112 | } |
113 | |
114 | static bool vhost_work_seq_done(struct vhost_dev *dev, struct vhost_work *work, |
115 | unsigned seq) |
116 | { |
117 | int left; |
118 | |
119 | spin_lock_irq(&dev->work_lock); |
120 | left = seq - work->done_seq; |
121 | spin_unlock_irq(&dev->work_lock); |
122 | return left <= 0; |
123 | } |
124 | |
125 | static void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work) |
126 | { |
127 | unsigned seq; |
128 | int flushing; |
129 | |
130 | spin_lock_irq(&dev->work_lock); |
131 | seq = work->queue_seq; |
132 | work->flushing++; |
133 | spin_unlock_irq(&dev->work_lock); |
134 | wait_event(work->done, vhost_work_seq_done(dev, work, seq)); |
135 | spin_lock_irq(&dev->work_lock); |
136 | flushing = --work->flushing; |
137 | spin_unlock_irq(&dev->work_lock); |
138 | BUG_ON(flushing < 0); |
139 | } |
140 | |
141 | /* Flush any work that has been scheduled. When calling this, don't hold any |
142 | * locks that are also used by the callback. */ |
143 | void vhost_poll_flush(struct vhost_poll *poll) |
144 | { |
145 | vhost_work_flush(poll->dev, &poll->work); |
146 | } |
147 | |
148 | void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work) |
149 | { |
150 | unsigned long flags; |
151 | |
152 | spin_lock_irqsave(&dev->work_lock, flags); |
153 | if (list_empty(&work->node)) { |
154 | list_add_tail(&work->node, &dev->work_list); |
155 | work->queue_seq++; |
156 | wake_up_process(dev->worker); |
157 | } |
158 | spin_unlock_irqrestore(&dev->work_lock, flags); |
159 | } |
160 | |
161 | void vhost_poll_queue(struct vhost_poll *poll) |
162 | { |
163 | vhost_work_queue(poll->dev, &poll->work); |
164 | } |
165 | |
166 | static void vhost_vq_reset(struct vhost_dev *dev, |
167 | struct vhost_virtqueue *vq) |
168 | { |
169 | vq->num = 1; |
170 | vq->desc = NULL; |
171 | vq->avail = NULL; |
172 | vq->used = NULL; |
173 | vq->last_avail_idx = 0; |
174 | vq->avail_idx = 0; |
175 | vq->last_used_idx = 0; |
176 | vq->signalled_used = 0; |
177 | vq->signalled_used_valid = false; |
178 | vq->used_flags = 0; |
179 | vq->log_used = false; |
180 | vq->log_addr = -1ull; |
181 | vq->vhost_hlen = 0; |
182 | vq->sock_hlen = 0; |
183 | vq->private_data = NULL; |
184 | vq->log_base = NULL; |
185 | vq->error_ctx = NULL; |
186 | vq->error = NULL; |
187 | vq->kick = NULL; |
188 | vq->call_ctx = NULL; |
189 | vq->call = NULL; |
190 | vq->log_ctx = NULL; |
191 | vq->upend_idx = 0; |
192 | vq->done_idx = 0; |
193 | vq->ubufs = NULL; |
194 | } |
195 | |
196 | static int vhost_worker(void *data) |
197 | { |
198 | struct vhost_dev *dev = data; |
199 | struct vhost_work *work = NULL; |
200 | unsigned uninitialized_var(seq); |
201 | mm_segment_t oldfs = get_fs(); |
202 | |
203 | set_fs(USER_DS); |
204 | use_mm(dev->mm); |
205 | |
206 | for (;;) { |
207 | /* mb paired w/ kthread_stop */ |
208 | set_current_state(TASK_INTERRUPTIBLE); |
209 | |
210 | spin_lock_irq(&dev->work_lock); |
211 | if (work) { |
212 | work->done_seq = seq; |
213 | if (work->flushing) |
214 | wake_up_all(&work->done); |
215 | } |
216 | |
217 | if (kthread_should_stop()) { |
218 | spin_unlock_irq(&dev->work_lock); |
219 | __set_current_state(TASK_RUNNING); |
220 | break; |
221 | } |
222 | if (!list_empty(&dev->work_list)) { |
223 | work = list_first_entry(&dev->work_list, |
224 | struct vhost_work, node); |
225 | list_del_init(&work->node); |
226 | seq = work->queue_seq; |
227 | } else |
228 | work = NULL; |
229 | spin_unlock_irq(&dev->work_lock); |
230 | |
231 | if (work) { |
232 | __set_current_state(TASK_RUNNING); |
233 | work->fn(work); |
234 | if (need_resched()) |
235 | schedule(); |
236 | } else |
237 | schedule(); |
238 | |
239 | } |
240 | unuse_mm(dev->mm); |
241 | set_fs(oldfs); |
242 | return 0; |
243 | } |
244 | |
245 | static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq) |
246 | { |
247 | kfree(vq->indirect); |
248 | vq->indirect = NULL; |
249 | kfree(vq->log); |
250 | vq->log = NULL; |
251 | kfree(vq->heads); |
252 | vq->heads = NULL; |
253 | kfree(vq->ubuf_info); |
254 | vq->ubuf_info = NULL; |
255 | } |
256 | |
257 | void vhost_enable_zcopy(int vq) |
258 | { |
259 | vhost_zcopy_mask |= 0x1 << vq; |
260 | } |
261 | |
262 | /* Helper to allocate iovec buffers for all vqs. */ |
263 | static long vhost_dev_alloc_iovecs(struct vhost_dev *dev) |
264 | { |
265 | int i; |
266 | bool zcopy; |
267 | |
268 | for (i = 0; i < dev->nvqs; ++i) { |
269 | dev->vqs[i].indirect = kmalloc(sizeof *dev->vqs[i].indirect * |
270 | UIO_MAXIOV, GFP_KERNEL); |
271 | dev->vqs[i].log = kmalloc(sizeof *dev->vqs[i].log * UIO_MAXIOV, |
272 | GFP_KERNEL); |
273 | dev->vqs[i].heads = kmalloc(sizeof *dev->vqs[i].heads * |
274 | UIO_MAXIOV, GFP_KERNEL); |
275 | zcopy = vhost_zcopy_mask & (0x1 << i); |
276 | if (zcopy) |
277 | dev->vqs[i].ubuf_info = |
278 | kmalloc(sizeof *dev->vqs[i].ubuf_info * |
279 | UIO_MAXIOV, GFP_KERNEL); |
280 | if (!dev->vqs[i].indirect || !dev->vqs[i].log || |
281 | !dev->vqs[i].heads || |
282 | (zcopy && !dev->vqs[i].ubuf_info)) |
283 | goto err_nomem; |
284 | } |
285 | return 0; |
286 | |
287 | err_nomem: |
288 | for (; i >= 0; --i) |
289 | vhost_vq_free_iovecs(&dev->vqs[i]); |
290 | return -ENOMEM; |
291 | } |
292 | |
293 | static void vhost_dev_free_iovecs(struct vhost_dev *dev) |
294 | { |
295 | int i; |
296 | |
297 | for (i = 0; i < dev->nvqs; ++i) |
298 | vhost_vq_free_iovecs(&dev->vqs[i]); |
299 | } |
300 | |
301 | long vhost_dev_init(struct vhost_dev *dev, |
302 | struct vhost_virtqueue *vqs, int nvqs) |
303 | { |
304 | int i; |
305 | |
306 | dev->vqs = vqs; |
307 | dev->nvqs = nvqs; |
308 | mutex_init(&dev->mutex); |
309 | dev->log_ctx = NULL; |
310 | dev->log_file = NULL; |
311 | dev->memory = NULL; |
312 | dev->mm = NULL; |
313 | spin_lock_init(&dev->work_lock); |
314 | INIT_LIST_HEAD(&dev->work_list); |
315 | dev->worker = NULL; |
316 | |
317 | for (i = 0; i < dev->nvqs; ++i) { |
318 | dev->vqs[i].log = NULL; |
319 | dev->vqs[i].indirect = NULL; |
320 | dev->vqs[i].heads = NULL; |
321 | dev->vqs[i].ubuf_info = NULL; |
322 | dev->vqs[i].dev = dev; |
323 | mutex_init(&dev->vqs[i].mutex); |
324 | vhost_vq_reset(dev, dev->vqs + i); |
325 | if (dev->vqs[i].handle_kick) |
326 | vhost_poll_init(&dev->vqs[i].poll, |
327 | dev->vqs[i].handle_kick, POLLIN, dev); |
328 | } |
329 | |
330 | return 0; |
331 | } |
332 | |
333 | /* Caller should have device mutex */ |
334 | long vhost_dev_check_owner(struct vhost_dev *dev) |
335 | { |
336 | /* Are you the owner? If not, I don't think you mean to do that */ |
337 | return dev->mm == current->mm ? 0 : -EPERM; |
338 | } |
339 | |
340 | struct vhost_attach_cgroups_struct { |
341 | struct vhost_work work; |
342 | struct task_struct *owner; |
343 | int ret; |
344 | }; |
345 | |
346 | static void vhost_attach_cgroups_work(struct vhost_work *work) |
347 | { |
348 | struct vhost_attach_cgroups_struct *s; |
349 | |
350 | s = container_of(work, struct vhost_attach_cgroups_struct, work); |
351 | s->ret = cgroup_attach_task_all(s->owner, current); |
352 | } |
353 | |
354 | static int vhost_attach_cgroups(struct vhost_dev *dev) |
355 | { |
356 | struct vhost_attach_cgroups_struct attach; |
357 | |
358 | attach.owner = current; |
359 | vhost_work_init(&attach.work, vhost_attach_cgroups_work); |
360 | vhost_work_queue(dev, &attach.work); |
361 | vhost_work_flush(dev, &attach.work); |
362 | return attach.ret; |
363 | } |
364 | |
365 | /* Caller should have device mutex */ |
366 | static long vhost_dev_set_owner(struct vhost_dev *dev) |
367 | { |
368 | struct task_struct *worker; |
369 | int err; |
370 | |
371 | /* Is there an owner already? */ |
372 | if (dev->mm) { |
373 | err = -EBUSY; |
374 | goto err_mm; |
375 | } |
376 | |
377 | /* No owner, become one */ |
378 | dev->mm = get_task_mm(current); |
379 | worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid); |
380 | if (IS_ERR(worker)) { |
381 | err = PTR_ERR(worker); |
382 | goto err_worker; |
383 | } |
384 | |
385 | dev->worker = worker; |
386 | wake_up_process(worker); /* avoid contributing to loadavg */ |
387 | |
388 | err = vhost_attach_cgroups(dev); |
389 | if (err) |
390 | goto err_cgroup; |
391 | |
392 | err = vhost_dev_alloc_iovecs(dev); |
393 | if (err) |
394 | goto err_cgroup; |
395 | |
396 | return 0; |
397 | err_cgroup: |
398 | kthread_stop(worker); |
399 | dev->worker = NULL; |
400 | err_worker: |
401 | if (dev->mm) |
402 | mmput(dev->mm); |
403 | dev->mm = NULL; |
404 | err_mm: |
405 | return err; |
406 | } |
407 | |
408 | /* Caller should have device mutex */ |
409 | long vhost_dev_reset_owner(struct vhost_dev *dev) |
410 | { |
411 | struct vhost_memory *memory; |
412 | |
413 | /* Restore memory to default empty mapping. */ |
414 | memory = kmalloc(offsetof(struct vhost_memory, regions), GFP_KERNEL); |
415 | if (!memory) |
416 | return -ENOMEM; |
417 | |
418 | vhost_dev_cleanup(dev, true); |
419 | |
420 | memory->nregions = 0; |
421 | RCU_INIT_POINTER(dev->memory, memory); |
422 | return 0; |
423 | } |
424 | |
425 | void vhost_dev_stop(struct vhost_dev *dev) |
426 | { |
427 | int i; |
428 | |
429 | for (i = 0; i < dev->nvqs; ++i) { |
430 | if (dev->vqs[i].kick && dev->vqs[i].handle_kick) { |
431 | vhost_poll_stop(&dev->vqs[i].poll); |
432 | vhost_poll_flush(&dev->vqs[i].poll); |
433 | } |
434 | } |
435 | } |
436 | |
437 | /* Caller should have device mutex if and only if locked is set */ |
438 | void vhost_dev_cleanup(struct vhost_dev *dev, bool locked) |
439 | { |
440 | int i; |
441 | |
442 | for (i = 0; i < dev->nvqs; ++i) { |
443 | if (dev->vqs[i].error_ctx) |
444 | eventfd_ctx_put(dev->vqs[i].error_ctx); |
445 | if (dev->vqs[i].error) |
446 | fput(dev->vqs[i].error); |
447 | if (dev->vqs[i].kick) |
448 | fput(dev->vqs[i].kick); |
449 | if (dev->vqs[i].call_ctx) |
450 | eventfd_ctx_put(dev->vqs[i].call_ctx); |
451 | if (dev->vqs[i].call) |
452 | fput(dev->vqs[i].call); |
453 | vhost_vq_reset(dev, dev->vqs + i); |
454 | } |
455 | vhost_dev_free_iovecs(dev); |
456 | if (dev->log_ctx) |
457 | eventfd_ctx_put(dev->log_ctx); |
458 | dev->log_ctx = NULL; |
459 | if (dev->log_file) |
460 | fput(dev->log_file); |
461 | dev->log_file = NULL; |
462 | /* No one will access memory at this point */ |
463 | kfree(rcu_dereference_protected(dev->memory, |
464 | locked == |
465 | lockdep_is_held(&dev->mutex))); |
466 | RCU_INIT_POINTER(dev->memory, NULL); |
467 | WARN_ON(!list_empty(&dev->work_list)); |
468 | if (dev->worker) { |
469 | kthread_stop(dev->worker); |
470 | dev->worker = NULL; |
471 | } |
472 | if (dev->mm) |
473 | mmput(dev->mm); |
474 | dev->mm = NULL; |
475 | } |
476 | |
477 | static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz) |
478 | { |
479 | u64 a = addr / VHOST_PAGE_SIZE / 8; |
480 | |
481 | /* Make sure 64 bit math will not overflow. */ |
482 | if (a > ULONG_MAX - (unsigned long)log_base || |
483 | a + (unsigned long)log_base > ULONG_MAX) |
484 | return 0; |
485 | |
486 | return access_ok(VERIFY_WRITE, log_base + a, |
487 | (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8); |
488 | } |
489 | |
490 | /* Caller should have vq mutex and device mutex. */ |
491 | static int vq_memory_access_ok(void __user *log_base, struct vhost_memory *mem, |
492 | int log_all) |
493 | { |
494 | int i; |
495 | |
496 | if (!mem) |
497 | return 0; |
498 | |
499 | for (i = 0; i < mem->nregions; ++i) { |
500 | struct vhost_memory_region *m = mem->regions + i; |
501 | unsigned long a = m->userspace_addr; |
502 | if (m->memory_size > ULONG_MAX) |
503 | return 0; |
504 | else if (!access_ok(VERIFY_WRITE, (void __user *)a, |
505 | m->memory_size)) |
506 | return 0; |
507 | else if (log_all && !log_access_ok(log_base, |
508 | m->guest_phys_addr, |
509 | m->memory_size)) |
510 | return 0; |
511 | } |
512 | return 1; |
513 | } |
514 | |
515 | /* Can we switch to this memory table? */ |
516 | /* Caller should have device mutex but not vq mutex */ |
517 | static int memory_access_ok(struct vhost_dev *d, struct vhost_memory *mem, |
518 | int log_all) |
519 | { |
520 | int i; |
521 | |
522 | for (i = 0; i < d->nvqs; ++i) { |
523 | int ok; |
524 | mutex_lock(&d->vqs[i].mutex); |
525 | /* If ring is inactive, will check when it's enabled. */ |
526 | if (d->vqs[i].private_data) |
527 | ok = vq_memory_access_ok(d->vqs[i].log_base, mem, |
528 | log_all); |
529 | else |
530 | ok = 1; |
531 | mutex_unlock(&d->vqs[i].mutex); |
532 | if (!ok) |
533 | return 0; |
534 | } |
535 | return 1; |
536 | } |
537 | |
538 | static int vq_access_ok(struct vhost_dev *d, unsigned int num, |
539 | struct vring_desc __user *desc, |
540 | struct vring_avail __user *avail, |
541 | struct vring_used __user *used) |
542 | { |
543 | size_t s = vhost_has_feature(d, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; |
544 | return access_ok(VERIFY_READ, desc, num * sizeof *desc) && |
545 | access_ok(VERIFY_READ, avail, |
546 | sizeof *avail + num * sizeof *avail->ring + s) && |
547 | access_ok(VERIFY_WRITE, used, |
548 | sizeof *used + num * sizeof *used->ring + s); |
549 | } |
550 | |
551 | /* Can we log writes? */ |
552 | /* Caller should have device mutex but not vq mutex */ |
553 | int vhost_log_access_ok(struct vhost_dev *dev) |
554 | { |
555 | struct vhost_memory *mp; |
556 | |
557 | mp = rcu_dereference_protected(dev->memory, |
558 | lockdep_is_held(&dev->mutex)); |
559 | return memory_access_ok(dev, mp, 1); |
560 | } |
561 | |
562 | /* Verify access for write logging. */ |
563 | /* Caller should have vq mutex and device mutex */ |
564 | static int vq_log_access_ok(struct vhost_dev *d, struct vhost_virtqueue *vq, |
565 | void __user *log_base) |
566 | { |
567 | struct vhost_memory *mp; |
568 | size_t s = vhost_has_feature(d, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; |
569 | |
570 | mp = rcu_dereference_protected(vq->dev->memory, |
571 | lockdep_is_held(&vq->mutex)); |
572 | return vq_memory_access_ok(log_base, mp, |
573 | vhost_has_feature(vq->dev, VHOST_F_LOG_ALL)) && |
574 | (!vq->log_used || log_access_ok(log_base, vq->log_addr, |
575 | sizeof *vq->used + |
576 | vq->num * sizeof *vq->used->ring + s)); |
577 | } |
578 | |
579 | /* Can we start vq? */ |
580 | /* Caller should have vq mutex and device mutex */ |
581 | int vhost_vq_access_ok(struct vhost_virtqueue *vq) |
582 | { |
583 | return vq_access_ok(vq->dev, vq->num, vq->desc, vq->avail, vq->used) && |
584 | vq_log_access_ok(vq->dev, vq, vq->log_base); |
585 | } |
586 | |
587 | static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) |
588 | { |
589 | struct vhost_memory mem, *newmem, *oldmem; |
590 | unsigned long size = offsetof(struct vhost_memory, regions); |
591 | |
592 | if (copy_from_user(&mem, m, size)) |
593 | return -EFAULT; |
594 | if (mem.padding) |
595 | return -EOPNOTSUPP; |
596 | if (mem.nregions > VHOST_MEMORY_MAX_NREGIONS) |
597 | return -E2BIG; |
598 | newmem = kmalloc(size + mem.nregions * sizeof *m->regions, GFP_KERNEL); |
599 | if (!newmem) |
600 | return -ENOMEM; |
601 | |
602 | memcpy(newmem, &mem, size); |
603 | if (copy_from_user(newmem->regions, m->regions, |
604 | mem.nregions * sizeof *m->regions)) { |
605 | kfree(newmem); |
606 | return -EFAULT; |
607 | } |
608 | |
609 | if (!memory_access_ok(d, newmem, |
610 | vhost_has_feature(d, VHOST_F_LOG_ALL))) { |
611 | kfree(newmem); |
612 | return -EFAULT; |
613 | } |
614 | oldmem = rcu_dereference_protected(d->memory, |
615 | lockdep_is_held(&d->mutex)); |
616 | rcu_assign_pointer(d->memory, newmem); |
617 | synchronize_rcu(); |
618 | kfree(oldmem); |
619 | return 0; |
620 | } |
621 | |
622 | long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp) |
623 | { |
624 | struct file *eventfp, *filep = NULL; |
625 | bool pollstart = false, pollstop = false; |
626 | struct eventfd_ctx *ctx = NULL; |
627 | u32 __user *idxp = argp; |
628 | struct vhost_virtqueue *vq; |
629 | struct vhost_vring_state s; |
630 | struct vhost_vring_file f; |
631 | struct vhost_vring_addr a; |
632 | u32 idx; |
633 | long r; |
634 | |
635 | r = get_user(idx, idxp); |
636 | if (r < 0) |
637 | return r; |
638 | if (idx >= d->nvqs) |
639 | return -ENOBUFS; |
640 | |
641 | vq = d->vqs + idx; |
642 | |
643 | mutex_lock(&vq->mutex); |
644 | |
645 | switch (ioctl) { |
646 | case VHOST_SET_VRING_NUM: |
647 | /* Resizing ring with an active backend? |
648 | * You don't want to do that. */ |
649 | if (vq->private_data) { |
650 | r = -EBUSY; |
651 | break; |
652 | } |
653 | if (copy_from_user(&s, argp, sizeof s)) { |
654 | r = -EFAULT; |
655 | break; |
656 | } |
657 | if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) { |
658 | r = -EINVAL; |
659 | break; |
660 | } |
661 | vq->num = s.num; |
662 | break; |
663 | case VHOST_SET_VRING_BASE: |
664 | /* Moving base with an active backend? |
665 | * You don't want to do that. */ |
666 | if (vq->private_data) { |
667 | r = -EBUSY; |
668 | break; |
669 | } |
670 | if (copy_from_user(&s, argp, sizeof s)) { |
671 | r = -EFAULT; |
672 | break; |
673 | } |
674 | if (s.num > 0xffff) { |
675 | r = -EINVAL; |
676 | break; |
677 | } |
678 | vq->last_avail_idx = s.num; |
679 | /* Forget the cached index value. */ |
680 | vq->avail_idx = vq->last_avail_idx; |
681 | break; |
682 | case VHOST_GET_VRING_BASE: |
683 | s.index = idx; |
684 | s.num = vq->last_avail_idx; |
685 | if (copy_to_user(argp, &s, sizeof s)) |
686 | r = -EFAULT; |
687 | break; |
688 | case VHOST_SET_VRING_ADDR: |
689 | if (copy_from_user(&a, argp, sizeof a)) { |
690 | r = -EFAULT; |
691 | break; |
692 | } |
693 | if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) { |
694 | r = -EOPNOTSUPP; |
695 | break; |
696 | } |
697 | /* For 32bit, verify that the top 32bits of the user |
698 | data are set to zero. */ |
699 | if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr || |
700 | (u64)(unsigned long)a.used_user_addr != a.used_user_addr || |
701 | (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) { |
702 | r = -EFAULT; |
703 | break; |
704 | } |
705 | if ((a.avail_user_addr & (sizeof *vq->avail->ring - 1)) || |
706 | (a.used_user_addr & (sizeof *vq->used->ring - 1)) || |
707 | (a.log_guest_addr & (sizeof *vq->used->ring - 1))) { |
708 | r = -EINVAL; |
709 | break; |
710 | } |
711 | |
712 | /* We only verify access here if backend is configured. |
713 | * If it is not, we don't as size might not have been setup. |
714 | * We will verify when backend is configured. */ |
715 | if (vq->private_data) { |
716 | if (!vq_access_ok(d, vq->num, |
717 | (void __user *)(unsigned long)a.desc_user_addr, |
718 | (void __user *)(unsigned long)a.avail_user_addr, |
719 | (void __user *)(unsigned long)a.used_user_addr)) { |
720 | r = -EINVAL; |
721 | break; |
722 | } |
723 | |
724 | /* Also validate log access for used ring if enabled. */ |
725 | if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) && |
726 | !log_access_ok(vq->log_base, a.log_guest_addr, |
727 | sizeof *vq->used + |
728 | vq->num * sizeof *vq->used->ring)) { |
729 | r = -EINVAL; |
730 | break; |
731 | } |
732 | } |
733 | |
734 | vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG)); |
735 | vq->desc = (void __user *)(unsigned long)a.desc_user_addr; |
736 | vq->avail = (void __user *)(unsigned long)a.avail_user_addr; |
737 | vq->log_addr = a.log_guest_addr; |
738 | vq->used = (void __user *)(unsigned long)a.used_user_addr; |
739 | break; |
740 | case VHOST_SET_VRING_KICK: |
741 | if (copy_from_user(&f, argp, sizeof f)) { |
742 | r = -EFAULT; |
743 | break; |
744 | } |
745 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
746 | if (IS_ERR(eventfp)) { |
747 | r = PTR_ERR(eventfp); |
748 | break; |
749 | } |
750 | if (eventfp != vq->kick) { |
751 | pollstop = (filep = vq->kick) != NULL; |
752 | pollstart = (vq->kick = eventfp) != NULL; |
753 | } else |
754 | filep = eventfp; |
755 | break; |
756 | case VHOST_SET_VRING_CALL: |
757 | if (copy_from_user(&f, argp, sizeof f)) { |
758 | r = -EFAULT; |
759 | break; |
760 | } |
761 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
762 | if (IS_ERR(eventfp)) { |
763 | r = PTR_ERR(eventfp); |
764 | break; |
765 | } |
766 | if (eventfp != vq->call) { |
767 | filep = vq->call; |
768 | ctx = vq->call_ctx; |
769 | vq->call = eventfp; |
770 | vq->call_ctx = eventfp ? |
771 | eventfd_ctx_fileget(eventfp) : NULL; |
772 | } else |
773 | filep = eventfp; |
774 | break; |
775 | case VHOST_SET_VRING_ERR: |
776 | if (copy_from_user(&f, argp, sizeof f)) { |
777 | r = -EFAULT; |
778 | break; |
779 | } |
780 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
781 | if (IS_ERR(eventfp)) { |
782 | r = PTR_ERR(eventfp); |
783 | break; |
784 | } |
785 | if (eventfp != vq->error) { |
786 | filep = vq->error; |
787 | vq->error = eventfp; |
788 | ctx = vq->error_ctx; |
789 | vq->error_ctx = eventfp ? |
790 | eventfd_ctx_fileget(eventfp) : NULL; |
791 | } else |
792 | filep = eventfp; |
793 | break; |
794 | default: |
795 | r = -ENOIOCTLCMD; |
796 | } |
797 | |
798 | if (pollstop && vq->handle_kick) |
799 | vhost_poll_stop(&vq->poll); |
800 | |
801 | if (ctx) |
802 | eventfd_ctx_put(ctx); |
803 | if (filep) |
804 | fput(filep); |
805 | |
806 | if (pollstart && vq->handle_kick) |
807 | r = vhost_poll_start(&vq->poll, vq->kick); |
808 | |
809 | mutex_unlock(&vq->mutex); |
810 | |
811 | if (pollstop && vq->handle_kick) |
812 | vhost_poll_flush(&vq->poll); |
813 | return r; |
814 | } |
815 | |
816 | /* Caller must have device mutex */ |
817 | long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp) |
818 | { |
819 | struct file *eventfp, *filep = NULL; |
820 | struct eventfd_ctx *ctx = NULL; |
821 | u64 p; |
822 | long r; |
823 | int i, fd; |
824 | |
825 | /* If you are not the owner, you can become one */ |
826 | if (ioctl == VHOST_SET_OWNER) { |
827 | r = vhost_dev_set_owner(d); |
828 | goto done; |
829 | } |
830 | |
831 | /* You must be the owner to do anything else */ |
832 | r = vhost_dev_check_owner(d); |
833 | if (r) |
834 | goto done; |
835 | |
836 | switch (ioctl) { |
837 | case VHOST_SET_MEM_TABLE: |
838 | r = vhost_set_memory(d, argp); |
839 | break; |
840 | case VHOST_SET_LOG_BASE: |
841 | if (copy_from_user(&p, argp, sizeof p)) { |
842 | r = -EFAULT; |
843 | break; |
844 | } |
845 | if ((u64)(unsigned long)p != p) { |
846 | r = -EFAULT; |
847 | break; |
848 | } |
849 | for (i = 0; i < d->nvqs; ++i) { |
850 | struct vhost_virtqueue *vq; |
851 | void __user *base = (void __user *)(unsigned long)p; |
852 | vq = d->vqs + i; |
853 | mutex_lock(&vq->mutex); |
854 | /* If ring is inactive, will check when it's enabled. */ |
855 | if (vq->private_data && !vq_log_access_ok(d, vq, base)) |
856 | r = -EFAULT; |
857 | else |
858 | vq->log_base = base; |
859 | mutex_unlock(&vq->mutex); |
860 | } |
861 | break; |
862 | case VHOST_SET_LOG_FD: |
863 | r = get_user(fd, (int __user *)argp); |
864 | if (r < 0) |
865 | break; |
866 | eventfp = fd == -1 ? NULL : eventfd_fget(fd); |
867 | if (IS_ERR(eventfp)) { |
868 | r = PTR_ERR(eventfp); |
869 | break; |
870 | } |
871 | if (eventfp != d->log_file) { |
872 | filep = d->log_file; |
873 | ctx = d->log_ctx; |
874 | d->log_ctx = eventfp ? |
875 | eventfd_ctx_fileget(eventfp) : NULL; |
876 | } else |
877 | filep = eventfp; |
878 | for (i = 0; i < d->nvqs; ++i) { |
879 | mutex_lock(&d->vqs[i].mutex); |
880 | d->vqs[i].log_ctx = d->log_ctx; |
881 | mutex_unlock(&d->vqs[i].mutex); |
882 | } |
883 | if (ctx) |
884 | eventfd_ctx_put(ctx); |
885 | if (filep) |
886 | fput(filep); |
887 | break; |
888 | default: |
889 | r = -ENOIOCTLCMD; |
890 | break; |
891 | } |
892 | done: |
893 | return r; |
894 | } |
895 | |
896 | static const struct vhost_memory_region *find_region(struct vhost_memory *mem, |
897 | __u64 addr, __u32 len) |
898 | { |
899 | struct vhost_memory_region *reg; |
900 | int i; |
901 | |
902 | /* linear search is not brilliant, but we really have on the order of 6 |
903 | * regions in practice */ |
904 | for (i = 0; i < mem->nregions; ++i) { |
905 | reg = mem->regions + i; |
906 | if (reg->guest_phys_addr <= addr && |
907 | reg->guest_phys_addr + reg->memory_size - 1 >= addr) |
908 | return reg; |
909 | } |
910 | return NULL; |
911 | } |
912 | |
913 | /* TODO: This is really inefficient. We need something like get_user() |
914 | * (instruction directly accesses the data, with an exception table entry |
915 | * returning -EFAULT). See Documentation/x86/exception-tables.txt. |
916 | */ |
917 | static int set_bit_to_user(int nr, void __user *addr) |
918 | { |
919 | unsigned long log = (unsigned long)addr; |
920 | struct page *page; |
921 | void *base; |
922 | int bit = nr + (log % PAGE_SIZE) * 8; |
923 | int r; |
924 | |
925 | r = get_user_pages_fast(log, 1, 1, &page); |
926 | if (r < 0) |
927 | return r; |
928 | BUG_ON(r != 1); |
929 | base = kmap_atomic(page); |
930 | set_bit(bit, base); |
931 | kunmap_atomic(base); |
932 | set_page_dirty_lock(page); |
933 | put_page(page); |
934 | return 0; |
935 | } |
936 | |
937 | static int log_write(void __user *log_base, |
938 | u64 write_address, u64 write_length) |
939 | { |
940 | u64 write_page = write_address / VHOST_PAGE_SIZE; |
941 | int r; |
942 | |
943 | if (!write_length) |
944 | return 0; |
945 | write_length += write_address % VHOST_PAGE_SIZE; |
946 | for (;;) { |
947 | u64 base = (u64)(unsigned long)log_base; |
948 | u64 log = base + write_page / 8; |
949 | int bit = write_page % 8; |
950 | if ((u64)(unsigned long)log != log) |
951 | return -EFAULT; |
952 | r = set_bit_to_user(bit, (void __user *)(unsigned long)log); |
953 | if (r < 0) |
954 | return r; |
955 | if (write_length <= VHOST_PAGE_SIZE) |
956 | break; |
957 | write_length -= VHOST_PAGE_SIZE; |
958 | write_page += 1; |
959 | } |
960 | return r; |
961 | } |
962 | |
963 | int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, |
964 | unsigned int log_num, u64 len) |
965 | { |
966 | int i, r; |
967 | |
968 | /* Make sure data written is seen before log. */ |
969 | smp_wmb(); |
970 | for (i = 0; i < log_num; ++i) { |
971 | u64 l = min(log[i].len, len); |
972 | r = log_write(vq->log_base, log[i].addr, l); |
973 | if (r < 0) |
974 | return r; |
975 | len -= l; |
976 | if (!len) { |
977 | if (vq->log_ctx) |
978 | eventfd_signal(vq->log_ctx, 1); |
979 | return 0; |
980 | } |
981 | } |
982 | /* Length written exceeds what we have stored. This is a bug. */ |
983 | BUG(); |
984 | return 0; |
985 | } |
986 | |
987 | static int vhost_update_used_flags(struct vhost_virtqueue *vq) |
988 | { |
989 | void __user *used; |
990 | if (__put_user(vq->used_flags, &vq->used->flags) < 0) |
991 | return -EFAULT; |
992 | if (unlikely(vq->log_used)) { |
993 | /* Make sure the flag is seen before log. */ |
994 | smp_wmb(); |
995 | /* Log used flag write. */ |
996 | used = &vq->used->flags; |
997 | log_write(vq->log_base, vq->log_addr + |
998 | (used - (void __user *)vq->used), |
999 | sizeof vq->used->flags); |
1000 | if (vq->log_ctx) |
1001 | eventfd_signal(vq->log_ctx, 1); |
1002 | } |
1003 | return 0; |
1004 | } |
1005 | |
1006 | static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event) |
1007 | { |
1008 | if (__put_user(vq->avail_idx, vhost_avail_event(vq))) |
1009 | return -EFAULT; |
1010 | if (unlikely(vq->log_used)) { |
1011 | void __user *used; |
1012 | /* Make sure the event is seen before log. */ |
1013 | smp_wmb(); |
1014 | /* Log avail event write */ |
1015 | used = vhost_avail_event(vq); |
1016 | log_write(vq->log_base, vq->log_addr + |
1017 | (used - (void __user *)vq->used), |
1018 | sizeof *vhost_avail_event(vq)); |
1019 | if (vq->log_ctx) |
1020 | eventfd_signal(vq->log_ctx, 1); |
1021 | } |
1022 | return 0; |
1023 | } |
1024 | |
1025 | int vhost_init_used(struct vhost_virtqueue *vq) |
1026 | { |
1027 | int r; |
1028 | if (!vq->private_data) |
1029 | return 0; |
1030 | |
1031 | r = vhost_update_used_flags(vq); |
1032 | if (r) |
1033 | return r; |
1034 | vq->signalled_used_valid = false; |
1035 | return get_user(vq->last_used_idx, &vq->used->idx); |
1036 | } |
1037 | |
1038 | static int translate_desc(struct vhost_dev *dev, u64 addr, u32 len, |
1039 | struct iovec iov[], int iov_size) |
1040 | { |
1041 | const struct vhost_memory_region *reg; |
1042 | struct vhost_memory *mem; |
1043 | struct iovec *_iov; |
1044 | u64 s = 0; |
1045 | int ret = 0; |
1046 | |
1047 | rcu_read_lock(); |
1048 | |
1049 | mem = rcu_dereference(dev->memory); |
1050 | while ((u64)len > s) { |
1051 | u64 size; |
1052 | if (unlikely(ret >= iov_size)) { |
1053 | ret = -ENOBUFS; |
1054 | break; |
1055 | } |
1056 | reg = find_region(mem, addr, len); |
1057 | if (unlikely(!reg)) { |
1058 | ret = -EFAULT; |
1059 | break; |
1060 | } |
1061 | _iov = iov + ret; |
1062 | size = reg->memory_size - addr + reg->guest_phys_addr; |
1063 | _iov->iov_len = min((u64)len - s, size); |
1064 | _iov->iov_base = (void __user *)(unsigned long) |
1065 | (reg->userspace_addr + addr - reg->guest_phys_addr); |
1066 | s += size; |
1067 | addr += size; |
1068 | ++ret; |
1069 | } |
1070 | |
1071 | rcu_read_unlock(); |
1072 | return ret; |
1073 | } |
1074 | |
1075 | /* Each buffer in the virtqueues is actually a chain of descriptors. This |
1076 | * function returns the next descriptor in the chain, |
1077 | * or -1U if we're at the end. */ |
1078 | static unsigned next_desc(struct vring_desc *desc) |
1079 | { |
1080 | unsigned int next; |
1081 | |
1082 | /* If this descriptor says it doesn't chain, we're done. */ |
1083 | if (!(desc->flags & VRING_DESC_F_NEXT)) |
1084 | return -1U; |
1085 | |
1086 | /* Check they're not leading us off end of descriptors. */ |
1087 | next = desc->next; |
1088 | /* Make sure compiler knows to grab that: we don't want it changing! */ |
1089 | /* We will use the result as an index in an array, so most |
1090 | * architectures only need a compiler barrier here. */ |
1091 | read_barrier_depends(); |
1092 | |
1093 | return next; |
1094 | } |
1095 | |
1096 | static int get_indirect(struct vhost_dev *dev, struct vhost_virtqueue *vq, |
1097 | struct iovec iov[], unsigned int iov_size, |
1098 | unsigned int *out_num, unsigned int *in_num, |
1099 | struct vhost_log *log, unsigned int *log_num, |
1100 | struct vring_desc *indirect) |
1101 | { |
1102 | struct vring_desc desc; |
1103 | unsigned int i = 0, count, found = 0; |
1104 | int ret; |
1105 | |
1106 | /* Sanity check */ |
1107 | if (unlikely(indirect->len % sizeof desc)) { |
1108 | vq_err(vq, "Invalid length in indirect descriptor: " |
1109 | "len 0x%llx not multiple of 0x%zx\n", |
1110 | (unsigned long long)indirect->len, |
1111 | sizeof desc); |
1112 | return -EINVAL; |
1113 | } |
1114 | |
1115 | ret = translate_desc(dev, indirect->addr, indirect->len, vq->indirect, |
1116 | UIO_MAXIOV); |
1117 | if (unlikely(ret < 0)) { |
1118 | vq_err(vq, "Translation failure %d in indirect.\n", ret); |
1119 | return ret; |
1120 | } |
1121 | |
1122 | /* We will use the result as an address to read from, so most |
1123 | * architectures only need a compiler barrier here. */ |
1124 | read_barrier_depends(); |
1125 | |
1126 | count = indirect->len / sizeof desc; |
1127 | /* Buffers are chained via a 16 bit next field, so |
1128 | * we can have at most 2^16 of these. */ |
1129 | if (unlikely(count > USHRT_MAX + 1)) { |
1130 | vq_err(vq, "Indirect buffer length too big: %d\n", |
1131 | indirect->len); |
1132 | return -E2BIG; |
1133 | } |
1134 | |
1135 | do { |
1136 | unsigned iov_count = *in_num + *out_num; |
1137 | if (unlikely(++found > count)) { |
1138 | vq_err(vq, "Loop detected: last one at %u " |
1139 | "indirect size %u\n", |
1140 | i, count); |
1141 | return -EINVAL; |
1142 | } |
1143 | if (unlikely(memcpy_fromiovec((unsigned char *)&desc, |
1144 | vq->indirect, sizeof desc))) { |
1145 | vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n", |
1146 | i, (size_t)indirect->addr + i * sizeof desc); |
1147 | return -EINVAL; |
1148 | } |
1149 | if (unlikely(desc.flags & VRING_DESC_F_INDIRECT)) { |
1150 | vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n", |
1151 | i, (size_t)indirect->addr + i * sizeof desc); |
1152 | return -EINVAL; |
1153 | } |
1154 | |
1155 | ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, |
1156 | iov_size - iov_count); |
1157 | if (unlikely(ret < 0)) { |
1158 | vq_err(vq, "Translation failure %d indirect idx %d\n", |
1159 | ret, i); |
1160 | return ret; |
1161 | } |
1162 | /* If this is an input descriptor, increment that count. */ |
1163 | if (desc.flags & VRING_DESC_F_WRITE) { |
1164 | *in_num += ret; |
1165 | if (unlikely(log)) { |
1166 | log[*log_num].addr = desc.addr; |
1167 | log[*log_num].len = desc.len; |
1168 | ++*log_num; |
1169 | } |
1170 | } else { |
1171 | /* If it's an output descriptor, they're all supposed |
1172 | * to come before any input descriptors. */ |
1173 | if (unlikely(*in_num)) { |
1174 | vq_err(vq, "Indirect descriptor " |
1175 | "has out after in: idx %d\n", i); |
1176 | return -EINVAL; |
1177 | } |
1178 | *out_num += ret; |
1179 | } |
1180 | } while ((i = next_desc(&desc)) != -1); |
1181 | return 0; |
1182 | } |
1183 | |
1184 | /* This looks in the virtqueue and for the first available buffer, and converts |
1185 | * it to an iovec for convenient access. Since descriptors consist of some |
1186 | * number of output then some number of input descriptors, it's actually two |
1187 | * iovecs, but we pack them into one and note how many of each there were. |
1188 | * |
1189 | * This function returns the descriptor number found, or vq->num (which is |
1190 | * never a valid descriptor number) if none was found. A negative code is |
1191 | * returned on error. */ |
1192 | int vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq, |
1193 | struct iovec iov[], unsigned int iov_size, |
1194 | unsigned int *out_num, unsigned int *in_num, |
1195 | struct vhost_log *log, unsigned int *log_num) |
1196 | { |
1197 | struct vring_desc desc; |
1198 | unsigned int i, head, found = 0; |
1199 | u16 last_avail_idx; |
1200 | int ret; |
1201 | |
1202 | /* Check it isn't doing very strange things with descriptor numbers. */ |
1203 | last_avail_idx = vq->last_avail_idx; |
1204 | if (unlikely(__get_user(vq->avail_idx, &vq->avail->idx))) { |
1205 | vq_err(vq, "Failed to access avail idx at %p\n", |
1206 | &vq->avail->idx); |
1207 | return -EFAULT; |
1208 | } |
1209 | |
1210 | if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) { |
1211 | vq_err(vq, "Guest moved used index from %u to %u", |
1212 | last_avail_idx, vq->avail_idx); |
1213 | return -EFAULT; |
1214 | } |
1215 | |
1216 | /* If there's nothing new since last we looked, return invalid. */ |
1217 | if (vq->avail_idx == last_avail_idx) |
1218 | return vq->num; |
1219 | |
1220 | /* Only get avail ring entries after they have been exposed by guest. */ |
1221 | smp_rmb(); |
1222 | |
1223 | /* Grab the next descriptor number they're advertising, and increment |
1224 | * the index we've seen. */ |
1225 | if (unlikely(__get_user(head, |
1226 | &vq->avail->ring[last_avail_idx % vq->num]))) { |
1227 | vq_err(vq, "Failed to read head: idx %d address %p\n", |
1228 | last_avail_idx, |
1229 | &vq->avail->ring[last_avail_idx % vq->num]); |
1230 | return -EFAULT; |
1231 | } |
1232 | |
1233 | /* If their number is silly, that's an error. */ |
1234 | if (unlikely(head >= vq->num)) { |
1235 | vq_err(vq, "Guest says index %u > %u is available", |
1236 | head, vq->num); |
1237 | return -EINVAL; |
1238 | } |
1239 | |
1240 | /* When we start there are none of either input nor output. */ |
1241 | *out_num = *in_num = 0; |
1242 | if (unlikely(log)) |
1243 | *log_num = 0; |
1244 | |
1245 | i = head; |
1246 | do { |
1247 | unsigned iov_count = *in_num + *out_num; |
1248 | if (unlikely(i >= vq->num)) { |
1249 | vq_err(vq, "Desc index is %u > %u, head = %u", |
1250 | i, vq->num, head); |
1251 | return -EINVAL; |
1252 | } |
1253 | if (unlikely(++found > vq->num)) { |
1254 | vq_err(vq, "Loop detected: last one at %u " |
1255 | "vq size %u head %u\n", |
1256 | i, vq->num, head); |
1257 | return -EINVAL; |
1258 | } |
1259 | ret = __copy_from_user(&desc, vq->desc + i, sizeof desc); |
1260 | if (unlikely(ret)) { |
1261 | vq_err(vq, "Failed to get descriptor: idx %d addr %p\n", |
1262 | i, vq->desc + i); |
1263 | return -EFAULT; |
1264 | } |
1265 | if (desc.flags & VRING_DESC_F_INDIRECT) { |
1266 | ret = get_indirect(dev, vq, iov, iov_size, |
1267 | out_num, in_num, |
1268 | log, log_num, &desc); |
1269 | if (unlikely(ret < 0)) { |
1270 | vq_err(vq, "Failure detected " |
1271 | "in indirect descriptor at idx %d\n", i); |
1272 | return ret; |
1273 | } |
1274 | continue; |
1275 | } |
1276 | |
1277 | ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, |
1278 | iov_size - iov_count); |
1279 | if (unlikely(ret < 0)) { |
1280 | vq_err(vq, "Translation failure %d descriptor idx %d\n", |
1281 | ret, i); |
1282 | return ret; |
1283 | } |
1284 | if (desc.flags & VRING_DESC_F_WRITE) { |
1285 | /* If this is an input descriptor, |
1286 | * increment that count. */ |
1287 | *in_num += ret; |
1288 | if (unlikely(log)) { |
1289 | log[*log_num].addr = desc.addr; |
1290 | log[*log_num].len = desc.len; |
1291 | ++*log_num; |
1292 | } |
1293 | } else { |
1294 | /* If it's an output descriptor, they're all supposed |
1295 | * to come before any input descriptors. */ |
1296 | if (unlikely(*in_num)) { |
1297 | vq_err(vq, "Descriptor has out after in: " |
1298 | "idx %d\n", i); |
1299 | return -EINVAL; |
1300 | } |
1301 | *out_num += ret; |
1302 | } |
1303 | } while ((i = next_desc(&desc)) != -1); |
1304 | |
1305 | /* On success, increment avail index. */ |
1306 | vq->last_avail_idx++; |
1307 | |
1308 | /* Assume notifications from guest are disabled at this point, |
1309 | * if they aren't we would need to update avail_event index. */ |
1310 | BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY)); |
1311 | return head; |
1312 | } |
1313 | |
1314 | /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */ |
1315 | void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n) |
1316 | { |
1317 | vq->last_avail_idx -= n; |
1318 | } |
1319 | |
1320 | /* After we've used one of their buffers, we tell them about it. We'll then |
1321 | * want to notify the guest, using eventfd. */ |
1322 | int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len) |
1323 | { |
1324 | struct vring_used_elem __user *used; |
1325 | |
1326 | /* The virtqueue contains a ring of used buffers. Get a pointer to the |
1327 | * next entry in that used ring. */ |
1328 | used = &vq->used->ring[vq->last_used_idx % vq->num]; |
1329 | if (__put_user(head, &used->id)) { |
1330 | vq_err(vq, "Failed to write used id"); |
1331 | return -EFAULT; |
1332 | } |
1333 | if (__put_user(len, &used->len)) { |
1334 | vq_err(vq, "Failed to write used len"); |
1335 | return -EFAULT; |
1336 | } |
1337 | /* Make sure buffer is written before we update index. */ |
1338 | smp_wmb(); |
1339 | if (__put_user(vq->last_used_idx + 1, &vq->used->idx)) { |
1340 | vq_err(vq, "Failed to increment used idx"); |
1341 | return -EFAULT; |
1342 | } |
1343 | if (unlikely(vq->log_used)) { |
1344 | /* Make sure data is seen before log. */ |
1345 | smp_wmb(); |
1346 | /* Log used ring entry write. */ |
1347 | log_write(vq->log_base, |
1348 | vq->log_addr + |
1349 | ((void __user *)used - (void __user *)vq->used), |
1350 | sizeof *used); |
1351 | /* Log used index update. */ |
1352 | log_write(vq->log_base, |
1353 | vq->log_addr + offsetof(struct vring_used, idx), |
1354 | sizeof vq->used->idx); |
1355 | if (vq->log_ctx) |
1356 | eventfd_signal(vq->log_ctx, 1); |
1357 | } |
1358 | vq->last_used_idx++; |
1359 | /* If the driver never bothers to signal in a very long while, |
1360 | * used index might wrap around. If that happens, invalidate |
1361 | * signalled_used index we stored. TODO: make sure driver |
1362 | * signals at least once in 2^16 and remove this. */ |
1363 | if (unlikely(vq->last_used_idx == vq->signalled_used)) |
1364 | vq->signalled_used_valid = false; |
1365 | return 0; |
1366 | } |
1367 | |
1368 | static int __vhost_add_used_n(struct vhost_virtqueue *vq, |
1369 | struct vring_used_elem *heads, |
1370 | unsigned count) |
1371 | { |
1372 | struct vring_used_elem __user *used; |
1373 | u16 old, new; |
1374 | int start; |
1375 | |
1376 | start = vq->last_used_idx % vq->num; |
1377 | used = vq->used->ring + start; |
1378 | if (__copy_to_user(used, heads, count * sizeof *used)) { |
1379 | vq_err(vq, "Failed to write used"); |
1380 | return -EFAULT; |
1381 | } |
1382 | if (unlikely(vq->log_used)) { |
1383 | /* Make sure data is seen before log. */ |
1384 | smp_wmb(); |
1385 | /* Log used ring entry write. */ |
1386 | log_write(vq->log_base, |
1387 | vq->log_addr + |
1388 | ((void __user *)used - (void __user *)vq->used), |
1389 | count * sizeof *used); |
1390 | } |
1391 | old = vq->last_used_idx; |
1392 | new = (vq->last_used_idx += count); |
1393 | /* If the driver never bothers to signal in a very long while, |
1394 | * used index might wrap around. If that happens, invalidate |
1395 | * signalled_used index we stored. TODO: make sure driver |
1396 | * signals at least once in 2^16 and remove this. */ |
1397 | if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old))) |
1398 | vq->signalled_used_valid = false; |
1399 | return 0; |
1400 | } |
1401 | |
1402 | /* After we've used one of their buffers, we tell them about it. We'll then |
1403 | * want to notify the guest, using eventfd. */ |
1404 | int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads, |
1405 | unsigned count) |
1406 | { |
1407 | int start, n, r; |
1408 | |
1409 | start = vq->last_used_idx % vq->num; |
1410 | n = vq->num - start; |
1411 | if (n < count) { |
1412 | r = __vhost_add_used_n(vq, heads, n); |
1413 | if (r < 0) |
1414 | return r; |
1415 | heads += n; |
1416 | count -= n; |
1417 | } |
1418 | r = __vhost_add_used_n(vq, heads, count); |
1419 | |
1420 | /* Make sure buffer is written before we update index. */ |
1421 | smp_wmb(); |
1422 | if (put_user(vq->last_used_idx, &vq->used->idx)) { |
1423 | vq_err(vq, "Failed to increment used idx"); |
1424 | return -EFAULT; |
1425 | } |
1426 | if (unlikely(vq->log_used)) { |
1427 | /* Log used index update. */ |
1428 | log_write(vq->log_base, |
1429 | vq->log_addr + offsetof(struct vring_used, idx), |
1430 | sizeof vq->used->idx); |
1431 | if (vq->log_ctx) |
1432 | eventfd_signal(vq->log_ctx, 1); |
1433 | } |
1434 | return r; |
1435 | } |
1436 | |
1437 | static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
1438 | { |
1439 | __u16 old, new, event; |
1440 | bool v; |
1441 | /* Flush out used index updates. This is paired |
1442 | * with the barrier that the Guest executes when enabling |
1443 | * interrupts. */ |
1444 | smp_mb(); |
1445 | |
1446 | if (vhost_has_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY) && |
1447 | unlikely(vq->avail_idx == vq->last_avail_idx)) |
1448 | return true; |
1449 | |
1450 | if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { |
1451 | __u16 flags; |
1452 | if (__get_user(flags, &vq->avail->flags)) { |
1453 | vq_err(vq, "Failed to get flags"); |
1454 | return true; |
1455 | } |
1456 | return !(flags & VRING_AVAIL_F_NO_INTERRUPT); |
1457 | } |
1458 | old = vq->signalled_used; |
1459 | v = vq->signalled_used_valid; |
1460 | new = vq->signalled_used = vq->last_used_idx; |
1461 | vq->signalled_used_valid = true; |
1462 | |
1463 | if (unlikely(!v)) |
1464 | return true; |
1465 | |
1466 | if (get_user(event, vhost_used_event(vq))) { |
1467 | vq_err(vq, "Failed to get used event idx"); |
1468 | return true; |
1469 | } |
1470 | return vring_need_event(event, new, old); |
1471 | } |
1472 | |
1473 | /* This actually signals the guest, using eventfd. */ |
1474 | void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
1475 | { |
1476 | /* Signal the Guest tell them we used something up. */ |
1477 | if (vq->call_ctx && vhost_notify(dev, vq)) |
1478 | eventfd_signal(vq->call_ctx, 1); |
1479 | } |
1480 | |
1481 | /* And here's the combo meal deal. Supersize me! */ |
1482 | void vhost_add_used_and_signal(struct vhost_dev *dev, |
1483 | struct vhost_virtqueue *vq, |
1484 | unsigned int head, int len) |
1485 | { |
1486 | vhost_add_used(vq, head, len); |
1487 | vhost_signal(dev, vq); |
1488 | } |
1489 | |
1490 | /* multi-buffer version of vhost_add_used_and_signal */ |
1491 | void vhost_add_used_and_signal_n(struct vhost_dev *dev, |
1492 | struct vhost_virtqueue *vq, |
1493 | struct vring_used_elem *heads, unsigned count) |
1494 | { |
1495 | vhost_add_used_n(vq, heads, count); |
1496 | vhost_signal(dev, vq); |
1497 | } |
1498 | |
1499 | /* OK, now we need to know about added descriptors. */ |
1500 | bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
1501 | { |
1502 | u16 avail_idx; |
1503 | int r; |
1504 | |
1505 | if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY)) |
1506 | return false; |
1507 | vq->used_flags &= ~VRING_USED_F_NO_NOTIFY; |
1508 | if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { |
1509 | r = vhost_update_used_flags(vq); |
1510 | if (r) { |
1511 | vq_err(vq, "Failed to enable notification at %p: %d\n", |
1512 | &vq->used->flags, r); |
1513 | return false; |
1514 | } |
1515 | } else { |
1516 | r = vhost_update_avail_event(vq, vq->avail_idx); |
1517 | if (r) { |
1518 | vq_err(vq, "Failed to update avail event index at %p: %d\n", |
1519 | vhost_avail_event(vq), r); |
1520 | return false; |
1521 | } |
1522 | } |
1523 | /* They could have slipped one in as we were doing that: make |
1524 | * sure it's written, then check again. */ |
1525 | smp_mb(); |
1526 | r = __get_user(avail_idx, &vq->avail->idx); |
1527 | if (r) { |
1528 | vq_err(vq, "Failed to check avail idx at %p: %d\n", |
1529 | &vq->avail->idx, r); |
1530 | return false; |
1531 | } |
1532 | |
1533 | return avail_idx != vq->avail_idx; |
1534 | } |
1535 | |
1536 | /* We don't need to be notified again. */ |
1537 | void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
1538 | { |
1539 | int r; |
1540 | |
1541 | if (vq->used_flags & VRING_USED_F_NO_NOTIFY) |
1542 | return; |
1543 | vq->used_flags |= VRING_USED_F_NO_NOTIFY; |
1544 | if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { |
1545 | r = vhost_update_used_flags(vq); |
1546 | if (r) |
1547 | vq_err(vq, "Failed to enable notification at %p: %d\n", |
1548 | &vq->used->flags, r); |
1549 | } |
1550 | } |
1551 | |
1552 | static void vhost_zerocopy_done_signal(struct kref *kref) |
1553 | { |
1554 | struct vhost_ubuf_ref *ubufs = container_of(kref, struct vhost_ubuf_ref, |
1555 | kref); |
1556 | wake_up(&ubufs->wait); |
1557 | } |
1558 | |
1559 | struct vhost_ubuf_ref *vhost_ubuf_alloc(struct vhost_virtqueue *vq, |
1560 | bool zcopy) |
1561 | { |
1562 | struct vhost_ubuf_ref *ubufs; |
1563 | /* No zero copy backend? Nothing to count. */ |
1564 | if (!zcopy) |
1565 | return NULL; |
1566 | ubufs = kmalloc(sizeof *ubufs, GFP_KERNEL); |
1567 | if (!ubufs) |
1568 | return ERR_PTR(-ENOMEM); |
1569 | kref_init(&ubufs->kref); |
1570 | init_waitqueue_head(&ubufs->wait); |
1571 | ubufs->vq = vq; |
1572 | return ubufs; |
1573 | } |
1574 | |
1575 | void vhost_ubuf_put(struct vhost_ubuf_ref *ubufs) |
1576 | { |
1577 | kref_put(&ubufs->kref, vhost_zerocopy_done_signal); |
1578 | } |
1579 | |
1580 | void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *ubufs) |
1581 | { |
1582 | kref_put(&ubufs->kref, vhost_zerocopy_done_signal); |
1583 | wait_event(ubufs->wait, !atomic_read(&ubufs->kref.refcount)); |
1584 | kfree(ubufs); |
1585 | } |
1586 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
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master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9