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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 | |
7 | * Documentation/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/miscdevice.h> | |
19 | #include <linux/mutex.h> | |
3a4d5c94 MT |
20 | #include <linux/rcupdate.h> |
21 | #include <linux/poll.h> | |
22 | #include <linux/file.h> | |
23 | #include <linux/highmem.h> | |
5a0e3ad6 | 24 | #include <linux/slab.h> |
c23f3445 | 25 | #include <linux/kthread.h> |
9e3d1957 | 26 | #include <linux/cgroup.h> |
3a4d5c94 MT |
27 | |
28 | #include <linux/net.h> | |
29 | #include <linux/if_packet.h> | |
30 | #include <linux/if_arp.h> | |
31 | ||
32 | #include <net/sock.h> | |
33 | ||
34 | #include "vhost.h" | |
35 | ||
36 | enum { | |
37 | VHOST_MEMORY_MAX_NREGIONS = 64, | |
38 | VHOST_MEMORY_F_LOG = 0x1, | |
39 | }; | |
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; | |
45 | poll = container_of(pt, struct vhost_poll, table); | |
46 | ||
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 | ||
63 | /* Init poll structure */ | |
c23f3445 TH |
64 | void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, |
65 | unsigned long mask, struct vhost_dev *dev) | |
3a4d5c94 | 66 | { |
c23f3445 TH |
67 | struct vhost_work *work = &poll->work; |
68 | ||
3a4d5c94 MT |
69 | init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup); |
70 | init_poll_funcptr(&poll->table, vhost_poll_func); | |
71 | poll->mask = mask; | |
c23f3445 TH |
72 | poll->dev = dev; |
73 | ||
74 | INIT_LIST_HEAD(&work->node); | |
75 | work->fn = fn; | |
76 | init_waitqueue_head(&work->done); | |
77 | work->flushing = 0; | |
78 | work->queue_seq = work->done_seq = 0; | |
3a4d5c94 MT |
79 | } |
80 | ||
81 | /* Start polling a file. We add ourselves to file's wait queue. The caller must | |
82 | * keep a reference to a file until after vhost_poll_stop is called. */ | |
83 | void vhost_poll_start(struct vhost_poll *poll, struct file *file) | |
84 | { | |
85 | unsigned long mask; | |
86 | mask = file->f_op->poll(file, &poll->table); | |
87 | if (mask) | |
88 | vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask); | |
89 | } | |
90 | ||
91 | /* Stop polling a file. After this function returns, it becomes safe to drop the | |
92 | * file reference. You must also flush afterwards. */ | |
93 | void vhost_poll_stop(struct vhost_poll *poll) | |
94 | { | |
95 | remove_wait_queue(poll->wqh, &poll->wait); | |
96 | } | |
97 | ||
98 | /* Flush any work that has been scheduled. When calling this, don't hold any | |
99 | * locks that are also used by the callback. */ | |
100 | void vhost_poll_flush(struct vhost_poll *poll) | |
101 | { | |
c23f3445 TH |
102 | struct vhost_work *work = &poll->work; |
103 | unsigned seq; | |
104 | int left; | |
105 | int flushing; | |
106 | ||
107 | spin_lock_irq(&poll->dev->work_lock); | |
108 | seq = work->queue_seq; | |
109 | work->flushing++; | |
110 | spin_unlock_irq(&poll->dev->work_lock); | |
111 | wait_event(work->done, ({ | |
112 | spin_lock_irq(&poll->dev->work_lock); | |
113 | left = seq - work->done_seq <= 0; | |
114 | spin_unlock_irq(&poll->dev->work_lock); | |
115 | left; | |
116 | })); | |
117 | spin_lock_irq(&poll->dev->work_lock); | |
118 | flushing = --work->flushing; | |
119 | spin_unlock_irq(&poll->dev->work_lock); | |
120 | BUG_ON(flushing < 0); | |
3a4d5c94 MT |
121 | } |
122 | ||
123 | void vhost_poll_queue(struct vhost_poll *poll) | |
124 | { | |
c23f3445 TH |
125 | struct vhost_dev *dev = poll->dev; |
126 | struct vhost_work *work = &poll->work; | |
127 | unsigned long flags; | |
128 | ||
129 | spin_lock_irqsave(&dev->work_lock, flags); | |
130 | if (list_empty(&work->node)) { | |
131 | list_add_tail(&work->node, &dev->work_list); | |
132 | work->queue_seq++; | |
133 | wake_up_process(dev->worker); | |
134 | } | |
135 | spin_unlock_irqrestore(&dev->work_lock, flags); | |
3a4d5c94 MT |
136 | } |
137 | ||
138 | static void vhost_vq_reset(struct vhost_dev *dev, | |
139 | struct vhost_virtqueue *vq) | |
140 | { | |
141 | vq->num = 1; | |
142 | vq->desc = NULL; | |
143 | vq->avail = NULL; | |
144 | vq->used = NULL; | |
145 | vq->last_avail_idx = 0; | |
146 | vq->avail_idx = 0; | |
147 | vq->last_used_idx = 0; | |
148 | vq->used_flags = 0; | |
149 | vq->used_flags = 0; | |
150 | vq->log_used = false; | |
151 | vq->log_addr = -1ull; | |
8dd014ad DS |
152 | vq->vhost_hlen = 0; |
153 | vq->sock_hlen = 0; | |
3a4d5c94 MT |
154 | vq->private_data = NULL; |
155 | vq->log_base = NULL; | |
156 | vq->error_ctx = NULL; | |
157 | vq->error = NULL; | |
158 | vq->kick = NULL; | |
159 | vq->call_ctx = NULL; | |
160 | vq->call = NULL; | |
73a99f08 | 161 | vq->log_ctx = NULL; |
3a4d5c94 MT |
162 | } |
163 | ||
c23f3445 TH |
164 | static int vhost_worker(void *data) |
165 | { | |
166 | struct vhost_dev *dev = data; | |
167 | struct vhost_work *work = NULL; | |
168 | unsigned uninitialized_var(seq); | |
169 | ||
170 | for (;;) { | |
171 | /* mb paired w/ kthread_stop */ | |
172 | set_current_state(TASK_INTERRUPTIBLE); | |
173 | ||
174 | spin_lock_irq(&dev->work_lock); | |
175 | if (work) { | |
176 | work->done_seq = seq; | |
177 | if (work->flushing) | |
178 | wake_up_all(&work->done); | |
179 | } | |
180 | ||
181 | if (kthread_should_stop()) { | |
182 | spin_unlock_irq(&dev->work_lock); | |
183 | __set_current_state(TASK_RUNNING); | |
184 | return 0; | |
185 | } | |
186 | if (!list_empty(&dev->work_list)) { | |
187 | work = list_first_entry(&dev->work_list, | |
188 | struct vhost_work, node); | |
189 | list_del_init(&work->node); | |
190 | seq = work->queue_seq; | |
191 | } else | |
192 | work = NULL; | |
193 | spin_unlock_irq(&dev->work_lock); | |
194 | ||
195 | if (work) { | |
196 | __set_current_state(TASK_RUNNING); | |
197 | work->fn(work); | |
198 | } else | |
199 | schedule(); | |
200 | ||
201 | } | |
202 | } | |
203 | ||
3a4d5c94 MT |
204 | long vhost_dev_init(struct vhost_dev *dev, |
205 | struct vhost_virtqueue *vqs, int nvqs) | |
206 | { | |
207 | int i; | |
c23f3445 | 208 | |
3a4d5c94 MT |
209 | dev->vqs = vqs; |
210 | dev->nvqs = nvqs; | |
211 | mutex_init(&dev->mutex); | |
212 | dev->log_ctx = NULL; | |
213 | dev->log_file = NULL; | |
214 | dev->memory = NULL; | |
215 | dev->mm = NULL; | |
c23f3445 TH |
216 | spin_lock_init(&dev->work_lock); |
217 | INIT_LIST_HEAD(&dev->work_list); | |
218 | dev->worker = NULL; | |
3a4d5c94 MT |
219 | |
220 | for (i = 0; i < dev->nvqs; ++i) { | |
221 | dev->vqs[i].dev = dev; | |
222 | mutex_init(&dev->vqs[i].mutex); | |
223 | vhost_vq_reset(dev, dev->vqs + i); | |
224 | if (dev->vqs[i].handle_kick) | |
225 | vhost_poll_init(&dev->vqs[i].poll, | |
c23f3445 | 226 | dev->vqs[i].handle_kick, POLLIN, dev); |
3a4d5c94 | 227 | } |
c23f3445 | 228 | |
3a4d5c94 MT |
229 | return 0; |
230 | } | |
231 | ||
232 | /* Caller should have device mutex */ | |
233 | long vhost_dev_check_owner(struct vhost_dev *dev) | |
234 | { | |
235 | /* Are you the owner? If not, I don't think you mean to do that */ | |
236 | return dev->mm == current->mm ? 0 : -EPERM; | |
237 | } | |
238 | ||
239 | /* Caller should have device mutex */ | |
240 | static long vhost_dev_set_owner(struct vhost_dev *dev) | |
241 | { | |
c23f3445 TH |
242 | struct task_struct *worker; |
243 | int err; | |
3a4d5c94 | 244 | /* Is there an owner already? */ |
c23f3445 TH |
245 | if (dev->mm) { |
246 | err = -EBUSY; | |
247 | goto err_mm; | |
248 | } | |
3a4d5c94 MT |
249 | /* No owner, become one */ |
250 | dev->mm = get_task_mm(current); | |
c23f3445 TH |
251 | worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid); |
252 | if (IS_ERR(worker)) { | |
253 | err = PTR_ERR(worker); | |
254 | goto err_worker; | |
255 | } | |
256 | ||
257 | dev->worker = worker; | |
9e3d1957 MT |
258 | err = cgroup_attach_task_current_cg(worker); |
259 | if (err) | |
260 | goto err_cgroup; | |
c23f3445 TH |
261 | wake_up_process(worker); /* avoid contributing to loadavg */ |
262 | ||
3a4d5c94 | 263 | return 0; |
9e3d1957 MT |
264 | err_cgroup: |
265 | kthread_stop(worker); | |
c23f3445 TH |
266 | err_worker: |
267 | if (dev->mm) | |
268 | mmput(dev->mm); | |
269 | dev->mm = NULL; | |
270 | err_mm: | |
271 | return err; | |
3a4d5c94 MT |
272 | } |
273 | ||
274 | /* Caller should have device mutex */ | |
275 | long vhost_dev_reset_owner(struct vhost_dev *dev) | |
276 | { | |
277 | struct vhost_memory *memory; | |
278 | ||
279 | /* Restore memory to default empty mapping. */ | |
280 | memory = kmalloc(offsetof(struct vhost_memory, regions), GFP_KERNEL); | |
281 | if (!memory) | |
282 | return -ENOMEM; | |
283 | ||
284 | vhost_dev_cleanup(dev); | |
285 | ||
286 | memory->nregions = 0; | |
287 | dev->memory = memory; | |
288 | return 0; | |
289 | } | |
290 | ||
291 | /* Caller should have device mutex */ | |
292 | void vhost_dev_cleanup(struct vhost_dev *dev) | |
293 | { | |
294 | int i; | |
295 | for (i = 0; i < dev->nvqs; ++i) { | |
296 | if (dev->vqs[i].kick && dev->vqs[i].handle_kick) { | |
297 | vhost_poll_stop(&dev->vqs[i].poll); | |
298 | vhost_poll_flush(&dev->vqs[i].poll); | |
299 | } | |
300 | if (dev->vqs[i].error_ctx) | |
301 | eventfd_ctx_put(dev->vqs[i].error_ctx); | |
302 | if (dev->vqs[i].error) | |
303 | fput(dev->vqs[i].error); | |
304 | if (dev->vqs[i].kick) | |
305 | fput(dev->vqs[i].kick); | |
306 | if (dev->vqs[i].call_ctx) | |
307 | eventfd_ctx_put(dev->vqs[i].call_ctx); | |
308 | if (dev->vqs[i].call) | |
309 | fput(dev->vqs[i].call); | |
310 | vhost_vq_reset(dev, dev->vqs + i); | |
311 | } | |
312 | if (dev->log_ctx) | |
313 | eventfd_ctx_put(dev->log_ctx); | |
314 | dev->log_ctx = NULL; | |
315 | if (dev->log_file) | |
316 | fput(dev->log_file); | |
317 | dev->log_file = NULL; | |
318 | /* No one will access memory at this point */ | |
319 | kfree(dev->memory); | |
320 | dev->memory = NULL; | |
321 | if (dev->mm) | |
322 | mmput(dev->mm); | |
323 | dev->mm = NULL; | |
c23f3445 TH |
324 | |
325 | WARN_ON(!list_empty(&dev->work_list)); | |
326 | kthread_stop(dev->worker); | |
3a4d5c94 MT |
327 | } |
328 | ||
329 | static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz) | |
330 | { | |
331 | u64 a = addr / VHOST_PAGE_SIZE / 8; | |
332 | /* Make sure 64 bit math will not overflow. */ | |
333 | if (a > ULONG_MAX - (unsigned long)log_base || | |
334 | a + (unsigned long)log_base > ULONG_MAX) | |
335 | return -EFAULT; | |
336 | ||
337 | return access_ok(VERIFY_WRITE, log_base + a, | |
338 | (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8); | |
339 | } | |
340 | ||
341 | /* Caller should have vq mutex and device mutex. */ | |
342 | static int vq_memory_access_ok(void __user *log_base, struct vhost_memory *mem, | |
343 | int log_all) | |
344 | { | |
345 | int i; | |
179b284e | 346 | |
f8322fbe MT |
347 | if (!mem) |
348 | return 0; | |
179b284e | 349 | |
3a4d5c94 MT |
350 | for (i = 0; i < mem->nregions; ++i) { |
351 | struct vhost_memory_region *m = mem->regions + i; | |
352 | unsigned long a = m->userspace_addr; | |
353 | if (m->memory_size > ULONG_MAX) | |
354 | return 0; | |
355 | else if (!access_ok(VERIFY_WRITE, (void __user *)a, | |
356 | m->memory_size)) | |
357 | return 0; | |
358 | else if (log_all && !log_access_ok(log_base, | |
359 | m->guest_phys_addr, | |
360 | m->memory_size)) | |
361 | return 0; | |
362 | } | |
363 | return 1; | |
364 | } | |
365 | ||
366 | /* Can we switch to this memory table? */ | |
367 | /* Caller should have device mutex but not vq mutex */ | |
368 | static int memory_access_ok(struct vhost_dev *d, struct vhost_memory *mem, | |
369 | int log_all) | |
370 | { | |
371 | int i; | |
372 | for (i = 0; i < d->nvqs; ++i) { | |
373 | int ok; | |
374 | mutex_lock(&d->vqs[i].mutex); | |
375 | /* If ring is inactive, will check when it's enabled. */ | |
376 | if (d->vqs[i].private_data) | |
377 | ok = vq_memory_access_ok(d->vqs[i].log_base, mem, | |
378 | log_all); | |
379 | else | |
380 | ok = 1; | |
381 | mutex_unlock(&d->vqs[i].mutex); | |
382 | if (!ok) | |
383 | return 0; | |
384 | } | |
385 | return 1; | |
386 | } | |
387 | ||
388 | static int vq_access_ok(unsigned int num, | |
389 | struct vring_desc __user *desc, | |
390 | struct vring_avail __user *avail, | |
391 | struct vring_used __user *used) | |
392 | { | |
393 | return access_ok(VERIFY_READ, desc, num * sizeof *desc) && | |
394 | access_ok(VERIFY_READ, avail, | |
395 | sizeof *avail + num * sizeof *avail->ring) && | |
396 | access_ok(VERIFY_WRITE, used, | |
397 | sizeof *used + num * sizeof *used->ring); | |
398 | } | |
399 | ||
400 | /* Can we log writes? */ | |
401 | /* Caller should have device mutex but not vq mutex */ | |
402 | int vhost_log_access_ok(struct vhost_dev *dev) | |
403 | { | |
404 | return memory_access_ok(dev, dev->memory, 1); | |
405 | } | |
406 | ||
407 | /* Verify access for write logging. */ | |
408 | /* Caller should have vq mutex and device mutex */ | |
409 | static int vq_log_access_ok(struct vhost_virtqueue *vq, void __user *log_base) | |
410 | { | |
411 | return vq_memory_access_ok(log_base, vq->dev->memory, | |
412 | vhost_has_feature(vq->dev, VHOST_F_LOG_ALL)) && | |
413 | (!vq->log_used || log_access_ok(log_base, vq->log_addr, | |
414 | sizeof *vq->used + | |
415 | vq->num * sizeof *vq->used->ring)); | |
416 | } | |
417 | ||
418 | /* Can we start vq? */ | |
419 | /* Caller should have vq mutex and device mutex */ | |
420 | int vhost_vq_access_ok(struct vhost_virtqueue *vq) | |
421 | { | |
422 | return vq_access_ok(vq->num, vq->desc, vq->avail, vq->used) && | |
423 | vq_log_access_ok(vq, vq->log_base); | |
424 | } | |
425 | ||
426 | static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) | |
427 | { | |
428 | struct vhost_memory mem, *newmem, *oldmem; | |
429 | unsigned long size = offsetof(struct vhost_memory, regions); | |
7ad9c9d2 TY |
430 | if (copy_from_user(&mem, m, size)) |
431 | return -EFAULT; | |
3a4d5c94 MT |
432 | if (mem.padding) |
433 | return -EOPNOTSUPP; | |
434 | if (mem.nregions > VHOST_MEMORY_MAX_NREGIONS) | |
435 | return -E2BIG; | |
436 | newmem = kmalloc(size + mem.nregions * sizeof *m->regions, GFP_KERNEL); | |
437 | if (!newmem) | |
438 | return -ENOMEM; | |
439 | ||
440 | memcpy(newmem, &mem, size); | |
7ad9c9d2 TY |
441 | if (copy_from_user(newmem->regions, m->regions, |
442 | mem.nregions * sizeof *m->regions)) { | |
3a4d5c94 | 443 | kfree(newmem); |
7ad9c9d2 | 444 | return -EFAULT; |
3a4d5c94 MT |
445 | } |
446 | ||
a02c3789 TY |
447 | if (!memory_access_ok(d, newmem, vhost_has_feature(d, VHOST_F_LOG_ALL))) { |
448 | kfree(newmem); | |
3a4d5c94 | 449 | return -EFAULT; |
a02c3789 | 450 | } |
3a4d5c94 MT |
451 | oldmem = d->memory; |
452 | rcu_assign_pointer(d->memory, newmem); | |
453 | synchronize_rcu(); | |
454 | kfree(oldmem); | |
455 | return 0; | |
456 | } | |
457 | ||
458 | static int init_used(struct vhost_virtqueue *vq, | |
459 | struct vring_used __user *used) | |
460 | { | |
461 | int r = put_user(vq->used_flags, &used->flags); | |
462 | if (r) | |
463 | return r; | |
464 | return get_user(vq->last_used_idx, &used->idx); | |
465 | } | |
466 | ||
467 | static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp) | |
468 | { | |
469 | struct file *eventfp, *filep = NULL, | |
470 | *pollstart = NULL, *pollstop = NULL; | |
471 | struct eventfd_ctx *ctx = NULL; | |
472 | u32 __user *idxp = argp; | |
473 | struct vhost_virtqueue *vq; | |
474 | struct vhost_vring_state s; | |
475 | struct vhost_vring_file f; | |
476 | struct vhost_vring_addr a; | |
477 | u32 idx; | |
478 | long r; | |
479 | ||
480 | r = get_user(idx, idxp); | |
481 | if (r < 0) | |
482 | return r; | |
0f3d9a17 | 483 | if (idx >= d->nvqs) |
3a4d5c94 MT |
484 | return -ENOBUFS; |
485 | ||
486 | vq = d->vqs + idx; | |
487 | ||
488 | mutex_lock(&vq->mutex); | |
489 | ||
490 | switch (ioctl) { | |
491 | case VHOST_SET_VRING_NUM: | |
492 | /* Resizing ring with an active backend? | |
493 | * You don't want to do that. */ | |
494 | if (vq->private_data) { | |
495 | r = -EBUSY; | |
496 | break; | |
497 | } | |
7ad9c9d2 TY |
498 | if (copy_from_user(&s, argp, sizeof s)) { |
499 | r = -EFAULT; | |
3a4d5c94 | 500 | break; |
7ad9c9d2 | 501 | } |
3a4d5c94 MT |
502 | if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) { |
503 | r = -EINVAL; | |
504 | break; | |
505 | } | |
506 | vq->num = s.num; | |
507 | break; | |
508 | case VHOST_SET_VRING_BASE: | |
509 | /* Moving base with an active backend? | |
510 | * You don't want to do that. */ | |
511 | if (vq->private_data) { | |
512 | r = -EBUSY; | |
513 | break; | |
514 | } | |
7ad9c9d2 TY |
515 | if (copy_from_user(&s, argp, sizeof s)) { |
516 | r = -EFAULT; | |
3a4d5c94 | 517 | break; |
7ad9c9d2 | 518 | } |
3a4d5c94 MT |
519 | if (s.num > 0xffff) { |
520 | r = -EINVAL; | |
521 | break; | |
522 | } | |
523 | vq->last_avail_idx = s.num; | |
524 | /* Forget the cached index value. */ | |
525 | vq->avail_idx = vq->last_avail_idx; | |
526 | break; | |
527 | case VHOST_GET_VRING_BASE: | |
528 | s.index = idx; | |
529 | s.num = vq->last_avail_idx; | |
7ad9c9d2 TY |
530 | if (copy_to_user(argp, &s, sizeof s)) |
531 | r = -EFAULT; | |
3a4d5c94 MT |
532 | break; |
533 | case VHOST_SET_VRING_ADDR: | |
7ad9c9d2 TY |
534 | if (copy_from_user(&a, argp, sizeof a)) { |
535 | r = -EFAULT; | |
3a4d5c94 | 536 | break; |
7ad9c9d2 | 537 | } |
3a4d5c94 MT |
538 | if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) { |
539 | r = -EOPNOTSUPP; | |
540 | break; | |
541 | } | |
542 | /* For 32bit, verify that the top 32bits of the user | |
543 | data are set to zero. */ | |
544 | if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr || | |
545 | (u64)(unsigned long)a.used_user_addr != a.used_user_addr || | |
546 | (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) { | |
547 | r = -EFAULT; | |
548 | break; | |
549 | } | |
550 | if ((a.avail_user_addr & (sizeof *vq->avail->ring - 1)) || | |
551 | (a.used_user_addr & (sizeof *vq->used->ring - 1)) || | |
552 | (a.log_guest_addr & (sizeof *vq->used->ring - 1))) { | |
553 | r = -EINVAL; | |
554 | break; | |
555 | } | |
556 | ||
557 | /* We only verify access here if backend is configured. | |
558 | * If it is not, we don't as size might not have been setup. | |
559 | * We will verify when backend is configured. */ | |
560 | if (vq->private_data) { | |
561 | if (!vq_access_ok(vq->num, | |
562 | (void __user *)(unsigned long)a.desc_user_addr, | |
563 | (void __user *)(unsigned long)a.avail_user_addr, | |
564 | (void __user *)(unsigned long)a.used_user_addr)) { | |
565 | r = -EINVAL; | |
566 | break; | |
567 | } | |
568 | ||
569 | /* Also validate log access for used ring if enabled. */ | |
570 | if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) && | |
571 | !log_access_ok(vq->log_base, a.log_guest_addr, | |
572 | sizeof *vq->used + | |
573 | vq->num * sizeof *vq->used->ring)) { | |
574 | r = -EINVAL; | |
575 | break; | |
576 | } | |
577 | } | |
578 | ||
579 | r = init_used(vq, (struct vring_used __user *)(unsigned long) | |
580 | a.used_user_addr); | |
581 | if (r) | |
582 | break; | |
583 | vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG)); | |
584 | vq->desc = (void __user *)(unsigned long)a.desc_user_addr; | |
585 | vq->avail = (void __user *)(unsigned long)a.avail_user_addr; | |
586 | vq->log_addr = a.log_guest_addr; | |
587 | vq->used = (void __user *)(unsigned long)a.used_user_addr; | |
588 | break; | |
589 | case VHOST_SET_VRING_KICK: | |
7ad9c9d2 TY |
590 | if (copy_from_user(&f, argp, sizeof f)) { |
591 | r = -EFAULT; | |
3a4d5c94 | 592 | break; |
7ad9c9d2 | 593 | } |
3a4d5c94 | 594 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
595 | if (IS_ERR(eventfp)) { |
596 | r = PTR_ERR(eventfp); | |
597 | break; | |
598 | } | |
3a4d5c94 MT |
599 | if (eventfp != vq->kick) { |
600 | pollstop = filep = vq->kick; | |
601 | pollstart = vq->kick = eventfp; | |
602 | } else | |
603 | filep = eventfp; | |
604 | break; | |
605 | case VHOST_SET_VRING_CALL: | |
7ad9c9d2 TY |
606 | if (copy_from_user(&f, argp, sizeof f)) { |
607 | r = -EFAULT; | |
3a4d5c94 | 608 | break; |
7ad9c9d2 | 609 | } |
3a4d5c94 | 610 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
611 | if (IS_ERR(eventfp)) { |
612 | r = PTR_ERR(eventfp); | |
613 | break; | |
614 | } | |
3a4d5c94 MT |
615 | if (eventfp != vq->call) { |
616 | filep = vq->call; | |
617 | ctx = vq->call_ctx; | |
618 | vq->call = eventfp; | |
619 | vq->call_ctx = eventfp ? | |
620 | eventfd_ctx_fileget(eventfp) : NULL; | |
621 | } else | |
622 | filep = eventfp; | |
623 | break; | |
624 | case VHOST_SET_VRING_ERR: | |
7ad9c9d2 TY |
625 | if (copy_from_user(&f, argp, sizeof f)) { |
626 | r = -EFAULT; | |
3a4d5c94 | 627 | break; |
7ad9c9d2 | 628 | } |
3a4d5c94 | 629 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
630 | if (IS_ERR(eventfp)) { |
631 | r = PTR_ERR(eventfp); | |
632 | break; | |
633 | } | |
3a4d5c94 MT |
634 | if (eventfp != vq->error) { |
635 | filep = vq->error; | |
636 | vq->error = eventfp; | |
637 | ctx = vq->error_ctx; | |
638 | vq->error_ctx = eventfp ? | |
639 | eventfd_ctx_fileget(eventfp) : NULL; | |
640 | } else | |
641 | filep = eventfp; | |
642 | break; | |
643 | default: | |
644 | r = -ENOIOCTLCMD; | |
645 | } | |
646 | ||
647 | if (pollstop && vq->handle_kick) | |
648 | vhost_poll_stop(&vq->poll); | |
649 | ||
650 | if (ctx) | |
651 | eventfd_ctx_put(ctx); | |
652 | if (filep) | |
653 | fput(filep); | |
654 | ||
655 | if (pollstart && vq->handle_kick) | |
656 | vhost_poll_start(&vq->poll, vq->kick); | |
657 | ||
658 | mutex_unlock(&vq->mutex); | |
659 | ||
660 | if (pollstop && vq->handle_kick) | |
661 | vhost_poll_flush(&vq->poll); | |
662 | return r; | |
663 | } | |
664 | ||
665 | /* Caller must have device mutex */ | |
666 | long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, unsigned long arg) | |
667 | { | |
668 | void __user *argp = (void __user *)arg; | |
669 | struct file *eventfp, *filep = NULL; | |
670 | struct eventfd_ctx *ctx = NULL; | |
671 | u64 p; | |
672 | long r; | |
673 | int i, fd; | |
674 | ||
675 | /* If you are not the owner, you can become one */ | |
676 | if (ioctl == VHOST_SET_OWNER) { | |
677 | r = vhost_dev_set_owner(d); | |
678 | goto done; | |
679 | } | |
680 | ||
681 | /* You must be the owner to do anything else */ | |
682 | r = vhost_dev_check_owner(d); | |
683 | if (r) | |
684 | goto done; | |
685 | ||
686 | switch (ioctl) { | |
687 | case VHOST_SET_MEM_TABLE: | |
688 | r = vhost_set_memory(d, argp); | |
689 | break; | |
690 | case VHOST_SET_LOG_BASE: | |
7ad9c9d2 TY |
691 | if (copy_from_user(&p, argp, sizeof p)) { |
692 | r = -EFAULT; | |
3a4d5c94 | 693 | break; |
7ad9c9d2 | 694 | } |
3a4d5c94 MT |
695 | if ((u64)(unsigned long)p != p) { |
696 | r = -EFAULT; | |
697 | break; | |
698 | } | |
699 | for (i = 0; i < d->nvqs; ++i) { | |
700 | struct vhost_virtqueue *vq; | |
701 | void __user *base = (void __user *)(unsigned long)p; | |
702 | vq = d->vqs + i; | |
703 | mutex_lock(&vq->mutex); | |
704 | /* If ring is inactive, will check when it's enabled. */ | |
705 | if (vq->private_data && !vq_log_access_ok(vq, base)) | |
706 | r = -EFAULT; | |
707 | else | |
708 | vq->log_base = base; | |
709 | mutex_unlock(&vq->mutex); | |
710 | } | |
711 | break; | |
712 | case VHOST_SET_LOG_FD: | |
713 | r = get_user(fd, (int __user *)argp); | |
714 | if (r < 0) | |
715 | break; | |
716 | eventfp = fd == -1 ? NULL : eventfd_fget(fd); | |
717 | if (IS_ERR(eventfp)) { | |
718 | r = PTR_ERR(eventfp); | |
719 | break; | |
720 | } | |
721 | if (eventfp != d->log_file) { | |
722 | filep = d->log_file; | |
723 | ctx = d->log_ctx; | |
724 | d->log_ctx = eventfp ? | |
725 | eventfd_ctx_fileget(eventfp) : NULL; | |
726 | } else | |
727 | filep = eventfp; | |
728 | for (i = 0; i < d->nvqs; ++i) { | |
729 | mutex_lock(&d->vqs[i].mutex); | |
730 | d->vqs[i].log_ctx = d->log_ctx; | |
731 | mutex_unlock(&d->vqs[i].mutex); | |
732 | } | |
733 | if (ctx) | |
734 | eventfd_ctx_put(ctx); | |
735 | if (filep) | |
736 | fput(filep); | |
737 | break; | |
738 | default: | |
739 | r = vhost_set_vring(d, ioctl, argp); | |
740 | break; | |
741 | } | |
742 | done: | |
743 | return r; | |
744 | } | |
745 | ||
746 | static const struct vhost_memory_region *find_region(struct vhost_memory *mem, | |
747 | __u64 addr, __u32 len) | |
748 | { | |
749 | struct vhost_memory_region *reg; | |
750 | int i; | |
751 | /* linear search is not brilliant, but we really have on the order of 6 | |
752 | * regions in practice */ | |
753 | for (i = 0; i < mem->nregions; ++i) { | |
754 | reg = mem->regions + i; | |
755 | if (reg->guest_phys_addr <= addr && | |
756 | reg->guest_phys_addr + reg->memory_size - 1 >= addr) | |
757 | return reg; | |
758 | } | |
759 | return NULL; | |
760 | } | |
761 | ||
762 | /* TODO: This is really inefficient. We need something like get_user() | |
763 | * (instruction directly accesses the data, with an exception table entry | |
764 | * returning -EFAULT). See Documentation/x86/exception-tables.txt. | |
765 | */ | |
766 | static int set_bit_to_user(int nr, void __user *addr) | |
767 | { | |
768 | unsigned long log = (unsigned long)addr; | |
769 | struct page *page; | |
770 | void *base; | |
771 | int bit = nr + (log % PAGE_SIZE) * 8; | |
772 | int r; | |
773 | r = get_user_pages_fast(log, 1, 1, &page); | |
d6db3f5c | 774 | if (r < 0) |
3a4d5c94 | 775 | return r; |
d6db3f5c | 776 | BUG_ON(r != 1); |
3a4d5c94 MT |
777 | base = kmap_atomic(page, KM_USER0); |
778 | set_bit(bit, base); | |
779 | kunmap_atomic(base, KM_USER0); | |
780 | set_page_dirty_lock(page); | |
781 | put_page(page); | |
782 | return 0; | |
783 | } | |
784 | ||
785 | static int log_write(void __user *log_base, | |
786 | u64 write_address, u64 write_length) | |
787 | { | |
788 | int r; | |
789 | if (!write_length) | |
790 | return 0; | |
791 | write_address /= VHOST_PAGE_SIZE; | |
792 | for (;;) { | |
793 | u64 base = (u64)(unsigned long)log_base; | |
794 | u64 log = base + write_address / 8; | |
795 | int bit = write_address % 8; | |
796 | if ((u64)(unsigned long)log != log) | |
797 | return -EFAULT; | |
798 | r = set_bit_to_user(bit, (void __user *)(unsigned long)log); | |
799 | if (r < 0) | |
800 | return r; | |
801 | if (write_length <= VHOST_PAGE_SIZE) | |
802 | break; | |
803 | write_length -= VHOST_PAGE_SIZE; | |
804 | write_address += VHOST_PAGE_SIZE; | |
805 | } | |
806 | return r; | |
807 | } | |
808 | ||
809 | int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, | |
810 | unsigned int log_num, u64 len) | |
811 | { | |
812 | int i, r; | |
813 | ||
814 | /* Make sure data written is seen before log. */ | |
5659338c | 815 | smp_wmb(); |
3a4d5c94 MT |
816 | for (i = 0; i < log_num; ++i) { |
817 | u64 l = min(log[i].len, len); | |
818 | r = log_write(vq->log_base, log[i].addr, l); | |
819 | if (r < 0) | |
820 | return r; | |
821 | len -= l; | |
822 | if (!len) | |
823 | return 0; | |
824 | } | |
825 | if (vq->log_ctx) | |
826 | eventfd_signal(vq->log_ctx, 1); | |
827 | /* Length written exceeds what we have stored. This is a bug. */ | |
828 | BUG(); | |
829 | return 0; | |
830 | } | |
831 | ||
a8d3782f CH |
832 | static int translate_desc(struct vhost_dev *dev, u64 addr, u32 len, |
833 | struct iovec iov[], int iov_size) | |
3a4d5c94 MT |
834 | { |
835 | const struct vhost_memory_region *reg; | |
836 | struct vhost_memory *mem; | |
837 | struct iovec *_iov; | |
838 | u64 s = 0; | |
839 | int ret = 0; | |
840 | ||
841 | rcu_read_lock(); | |
842 | ||
843 | mem = rcu_dereference(dev->memory); | |
844 | while ((u64)len > s) { | |
845 | u64 size; | |
7b3384fc | 846 | if (unlikely(ret >= iov_size)) { |
3a4d5c94 MT |
847 | ret = -ENOBUFS; |
848 | break; | |
849 | } | |
850 | reg = find_region(mem, addr, len); | |
7b3384fc | 851 | if (unlikely(!reg)) { |
3a4d5c94 MT |
852 | ret = -EFAULT; |
853 | break; | |
854 | } | |
855 | _iov = iov + ret; | |
856 | size = reg->memory_size - addr + reg->guest_phys_addr; | |
857 | _iov->iov_len = min((u64)len, size); | |
a8d3782f | 858 | _iov->iov_base = (void __user *)(unsigned long) |
3a4d5c94 MT |
859 | (reg->userspace_addr + addr - reg->guest_phys_addr); |
860 | s += size; | |
861 | addr += size; | |
862 | ++ret; | |
863 | } | |
864 | ||
865 | rcu_read_unlock(); | |
866 | return ret; | |
867 | } | |
868 | ||
869 | /* Each buffer in the virtqueues is actually a chain of descriptors. This | |
870 | * function returns the next descriptor in the chain, | |
871 | * or -1U if we're at the end. */ | |
872 | static unsigned next_desc(struct vring_desc *desc) | |
873 | { | |
874 | unsigned int next; | |
875 | ||
876 | /* If this descriptor says it doesn't chain, we're done. */ | |
877 | if (!(desc->flags & VRING_DESC_F_NEXT)) | |
878 | return -1U; | |
879 | ||
880 | /* Check they're not leading us off end of descriptors. */ | |
881 | next = desc->next; | |
882 | /* Make sure compiler knows to grab that: we don't want it changing! */ | |
883 | /* We will use the result as an index in an array, so most | |
884 | * architectures only need a compiler barrier here. */ | |
885 | read_barrier_depends(); | |
886 | ||
887 | return next; | |
888 | } | |
889 | ||
7b3384fc MT |
890 | static int get_indirect(struct vhost_dev *dev, struct vhost_virtqueue *vq, |
891 | struct iovec iov[], unsigned int iov_size, | |
892 | unsigned int *out_num, unsigned int *in_num, | |
893 | struct vhost_log *log, unsigned int *log_num, | |
894 | struct vring_desc *indirect) | |
3a4d5c94 MT |
895 | { |
896 | struct vring_desc desc; | |
897 | unsigned int i = 0, count, found = 0; | |
898 | int ret; | |
899 | ||
900 | /* Sanity check */ | |
7b3384fc | 901 | if (unlikely(indirect->len % sizeof desc)) { |
3a4d5c94 MT |
902 | vq_err(vq, "Invalid length in indirect descriptor: " |
903 | "len 0x%llx not multiple of 0x%zx\n", | |
904 | (unsigned long long)indirect->len, | |
905 | sizeof desc); | |
906 | return -EINVAL; | |
907 | } | |
908 | ||
909 | ret = translate_desc(dev, indirect->addr, indirect->len, vq->indirect, | |
910 | ARRAY_SIZE(vq->indirect)); | |
7b3384fc | 911 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
912 | vq_err(vq, "Translation failure %d in indirect.\n", ret); |
913 | return ret; | |
914 | } | |
915 | ||
916 | /* We will use the result as an address to read from, so most | |
917 | * architectures only need a compiler barrier here. */ | |
918 | read_barrier_depends(); | |
919 | ||
920 | count = indirect->len / sizeof desc; | |
921 | /* Buffers are chained via a 16 bit next field, so | |
922 | * we can have at most 2^16 of these. */ | |
7b3384fc | 923 | if (unlikely(count > USHRT_MAX + 1)) { |
3a4d5c94 MT |
924 | vq_err(vq, "Indirect buffer length too big: %d\n", |
925 | indirect->len); | |
926 | return -E2BIG; | |
927 | } | |
928 | ||
929 | do { | |
930 | unsigned iov_count = *in_num + *out_num; | |
7b3384fc | 931 | if (unlikely(++found > count)) { |
3a4d5c94 MT |
932 | vq_err(vq, "Loop detected: last one at %u " |
933 | "indirect size %u\n", | |
934 | i, count); | |
935 | return -EINVAL; | |
936 | } | |
7b3384fc MT |
937 | if (unlikely(memcpy_fromiovec((unsigned char *)&desc, vq->indirect, |
938 | sizeof desc))) { | |
3a4d5c94 MT |
939 | vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n", |
940 | i, (size_t)indirect->addr + i * sizeof desc); | |
941 | return -EINVAL; | |
942 | } | |
7b3384fc | 943 | if (unlikely(desc.flags & VRING_DESC_F_INDIRECT)) { |
3a4d5c94 MT |
944 | vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n", |
945 | i, (size_t)indirect->addr + i * sizeof desc); | |
946 | return -EINVAL; | |
947 | } | |
948 | ||
949 | ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, | |
950 | iov_size - iov_count); | |
7b3384fc | 951 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
952 | vq_err(vq, "Translation failure %d indirect idx %d\n", |
953 | ret, i); | |
954 | return ret; | |
955 | } | |
956 | /* If this is an input descriptor, increment that count. */ | |
957 | if (desc.flags & VRING_DESC_F_WRITE) { | |
958 | *in_num += ret; | |
959 | if (unlikely(log)) { | |
960 | log[*log_num].addr = desc.addr; | |
961 | log[*log_num].len = desc.len; | |
962 | ++*log_num; | |
963 | } | |
964 | } else { | |
965 | /* If it's an output descriptor, they're all supposed | |
966 | * to come before any input descriptors. */ | |
7b3384fc | 967 | if (unlikely(*in_num)) { |
3a4d5c94 MT |
968 | vq_err(vq, "Indirect descriptor " |
969 | "has out after in: idx %d\n", i); | |
970 | return -EINVAL; | |
971 | } | |
972 | *out_num += ret; | |
973 | } | |
974 | } while ((i = next_desc(&desc)) != -1); | |
975 | return 0; | |
976 | } | |
977 | ||
978 | /* This looks in the virtqueue and for the first available buffer, and converts | |
979 | * it to an iovec for convenient access. Since descriptors consist of some | |
980 | * number of output then some number of input descriptors, it's actually two | |
981 | * iovecs, but we pack them into one and note how many of each there were. | |
982 | * | |
d5675bd2 MT |
983 | * This function returns the descriptor number found, or vq->num (which is |
984 | * never a valid descriptor number) if none was found. A negative code is | |
985 | * returned on error. */ | |
986 | int vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq, | |
987 | struct iovec iov[], unsigned int iov_size, | |
988 | unsigned int *out_num, unsigned int *in_num, | |
989 | struct vhost_log *log, unsigned int *log_num) | |
3a4d5c94 MT |
990 | { |
991 | struct vring_desc desc; | |
992 | unsigned int i, head, found = 0; | |
993 | u16 last_avail_idx; | |
994 | int ret; | |
995 | ||
996 | /* Check it isn't doing very strange things with descriptor numbers. */ | |
997 | last_avail_idx = vq->last_avail_idx; | |
7b3384fc | 998 | if (unlikely(get_user(vq->avail_idx, &vq->avail->idx))) { |
3a4d5c94 MT |
999 | vq_err(vq, "Failed to access avail idx at %p\n", |
1000 | &vq->avail->idx); | |
d5675bd2 | 1001 | return -EFAULT; |
3a4d5c94 MT |
1002 | } |
1003 | ||
7b3384fc | 1004 | if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) { |
3a4d5c94 MT |
1005 | vq_err(vq, "Guest moved used index from %u to %u", |
1006 | last_avail_idx, vq->avail_idx); | |
d5675bd2 | 1007 | return -EFAULT; |
3a4d5c94 MT |
1008 | } |
1009 | ||
1010 | /* If there's nothing new since last we looked, return invalid. */ | |
1011 | if (vq->avail_idx == last_avail_idx) | |
1012 | return vq->num; | |
1013 | ||
1014 | /* Only get avail ring entries after they have been exposed by guest. */ | |
5659338c | 1015 | smp_rmb(); |
3a4d5c94 MT |
1016 | |
1017 | /* Grab the next descriptor number they're advertising, and increment | |
1018 | * the index we've seen. */ | |
7b3384fc MT |
1019 | if (unlikely(get_user(head, |
1020 | &vq->avail->ring[last_avail_idx % vq->num]))) { | |
3a4d5c94 MT |
1021 | vq_err(vq, "Failed to read head: idx %d address %p\n", |
1022 | last_avail_idx, | |
1023 | &vq->avail->ring[last_avail_idx % vq->num]); | |
d5675bd2 | 1024 | return -EFAULT; |
3a4d5c94 MT |
1025 | } |
1026 | ||
1027 | /* If their number is silly, that's an error. */ | |
7b3384fc | 1028 | if (unlikely(head >= vq->num)) { |
3a4d5c94 MT |
1029 | vq_err(vq, "Guest says index %u > %u is available", |
1030 | head, vq->num); | |
d5675bd2 | 1031 | return -EINVAL; |
3a4d5c94 MT |
1032 | } |
1033 | ||
1034 | /* When we start there are none of either input nor output. */ | |
1035 | *out_num = *in_num = 0; | |
1036 | if (unlikely(log)) | |
1037 | *log_num = 0; | |
1038 | ||
1039 | i = head; | |
1040 | do { | |
1041 | unsigned iov_count = *in_num + *out_num; | |
7b3384fc | 1042 | if (unlikely(i >= vq->num)) { |
3a4d5c94 MT |
1043 | vq_err(vq, "Desc index is %u > %u, head = %u", |
1044 | i, vq->num, head); | |
d5675bd2 | 1045 | return -EINVAL; |
3a4d5c94 | 1046 | } |
7b3384fc | 1047 | if (unlikely(++found > vq->num)) { |
3a4d5c94 MT |
1048 | vq_err(vq, "Loop detected: last one at %u " |
1049 | "vq size %u head %u\n", | |
1050 | i, vq->num, head); | |
d5675bd2 | 1051 | return -EINVAL; |
3a4d5c94 MT |
1052 | } |
1053 | ret = copy_from_user(&desc, vq->desc + i, sizeof desc); | |
7b3384fc | 1054 | if (unlikely(ret)) { |
3a4d5c94 MT |
1055 | vq_err(vq, "Failed to get descriptor: idx %d addr %p\n", |
1056 | i, vq->desc + i); | |
d5675bd2 | 1057 | return -EFAULT; |
3a4d5c94 MT |
1058 | } |
1059 | if (desc.flags & VRING_DESC_F_INDIRECT) { | |
1060 | ret = get_indirect(dev, vq, iov, iov_size, | |
1061 | out_num, in_num, | |
1062 | log, log_num, &desc); | |
7b3384fc | 1063 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1064 | vq_err(vq, "Failure detected " |
1065 | "in indirect descriptor at idx %d\n", i); | |
d5675bd2 | 1066 | return ret; |
3a4d5c94 MT |
1067 | } |
1068 | continue; | |
1069 | } | |
1070 | ||
1071 | ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, | |
1072 | iov_size - iov_count); | |
7b3384fc | 1073 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1074 | vq_err(vq, "Translation failure %d descriptor idx %d\n", |
1075 | ret, i); | |
d5675bd2 | 1076 | return ret; |
3a4d5c94 MT |
1077 | } |
1078 | if (desc.flags & VRING_DESC_F_WRITE) { | |
1079 | /* If this is an input descriptor, | |
1080 | * increment that count. */ | |
1081 | *in_num += ret; | |
1082 | if (unlikely(log)) { | |
1083 | log[*log_num].addr = desc.addr; | |
1084 | log[*log_num].len = desc.len; | |
1085 | ++*log_num; | |
1086 | } | |
1087 | } else { | |
1088 | /* If it's an output descriptor, they're all supposed | |
1089 | * to come before any input descriptors. */ | |
7b3384fc | 1090 | if (unlikely(*in_num)) { |
3a4d5c94 MT |
1091 | vq_err(vq, "Descriptor has out after in: " |
1092 | "idx %d\n", i); | |
d5675bd2 | 1093 | return -EINVAL; |
3a4d5c94 MT |
1094 | } |
1095 | *out_num += ret; | |
1096 | } | |
1097 | } while ((i = next_desc(&desc)) != -1); | |
1098 | ||
1099 | /* On success, increment avail index. */ | |
1100 | vq->last_avail_idx++; | |
1101 | return head; | |
1102 | } | |
1103 | ||
1104 | /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */ | |
8dd014ad | 1105 | void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n) |
3a4d5c94 | 1106 | { |
8dd014ad | 1107 | vq->last_avail_idx -= n; |
3a4d5c94 MT |
1108 | } |
1109 | ||
1110 | /* After we've used one of their buffers, we tell them about it. We'll then | |
1111 | * want to notify the guest, using eventfd. */ | |
1112 | int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len) | |
1113 | { | |
a8d3782f | 1114 | struct vring_used_elem __user *used; |
3a4d5c94 MT |
1115 | |
1116 | /* The virtqueue contains a ring of used buffers. Get a pointer to the | |
1117 | * next entry in that used ring. */ | |
1118 | used = &vq->used->ring[vq->last_used_idx % vq->num]; | |
1119 | if (put_user(head, &used->id)) { | |
1120 | vq_err(vq, "Failed to write used id"); | |
1121 | return -EFAULT; | |
1122 | } | |
1123 | if (put_user(len, &used->len)) { | |
1124 | vq_err(vq, "Failed to write used len"); | |
1125 | return -EFAULT; | |
1126 | } | |
1127 | /* Make sure buffer is written before we update index. */ | |
5659338c | 1128 | smp_wmb(); |
3a4d5c94 MT |
1129 | if (put_user(vq->last_used_idx + 1, &vq->used->idx)) { |
1130 | vq_err(vq, "Failed to increment used idx"); | |
1131 | return -EFAULT; | |
1132 | } | |
1133 | if (unlikely(vq->log_used)) { | |
1134 | /* Make sure data is seen before log. */ | |
5659338c | 1135 | smp_wmb(); |
86e9424d MT |
1136 | /* Log used ring entry write. */ |
1137 | log_write(vq->log_base, | |
a8d3782f CH |
1138 | vq->log_addr + |
1139 | ((void __user *)used - (void __user *)vq->used), | |
86e9424d MT |
1140 | sizeof *used); |
1141 | /* Log used index update. */ | |
1142 | log_write(vq->log_base, | |
1143 | vq->log_addr + offsetof(struct vring_used, idx), | |
1144 | sizeof vq->used->idx); | |
3a4d5c94 MT |
1145 | if (vq->log_ctx) |
1146 | eventfd_signal(vq->log_ctx, 1); | |
1147 | } | |
1148 | vq->last_used_idx++; | |
1149 | return 0; | |
1150 | } | |
1151 | ||
8dd014ad DS |
1152 | static int __vhost_add_used_n(struct vhost_virtqueue *vq, |
1153 | struct vring_used_elem *heads, | |
1154 | unsigned count) | |
1155 | { | |
1156 | struct vring_used_elem __user *used; | |
1157 | int start; | |
1158 | ||
1159 | start = vq->last_used_idx % vq->num; | |
1160 | used = vq->used->ring + start; | |
1161 | if (copy_to_user(used, heads, count * sizeof *used)) { | |
1162 | vq_err(vq, "Failed to write used"); | |
1163 | return -EFAULT; | |
1164 | } | |
1165 | if (unlikely(vq->log_used)) { | |
1166 | /* Make sure data is seen before log. */ | |
1167 | smp_wmb(); | |
1168 | /* Log used ring entry write. */ | |
1169 | log_write(vq->log_base, | |
1170 | vq->log_addr + | |
1171 | ((void __user *)used - (void __user *)vq->used), | |
1172 | count * sizeof *used); | |
1173 | } | |
1174 | vq->last_used_idx += count; | |
1175 | return 0; | |
1176 | } | |
1177 | ||
1178 | /* After we've used one of their buffers, we tell them about it. We'll then | |
1179 | * want to notify the guest, using eventfd. */ | |
1180 | int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads, | |
1181 | unsigned count) | |
1182 | { | |
1183 | int start, n, r; | |
1184 | ||
1185 | start = vq->last_used_idx % vq->num; | |
1186 | n = vq->num - start; | |
1187 | if (n < count) { | |
1188 | r = __vhost_add_used_n(vq, heads, n); | |
1189 | if (r < 0) | |
1190 | return r; | |
1191 | heads += n; | |
1192 | count -= n; | |
1193 | } | |
1194 | r = __vhost_add_used_n(vq, heads, count); | |
1195 | ||
1196 | /* Make sure buffer is written before we update index. */ | |
1197 | smp_wmb(); | |
1198 | if (put_user(vq->last_used_idx, &vq->used->idx)) { | |
1199 | vq_err(vq, "Failed to increment used idx"); | |
1200 | return -EFAULT; | |
1201 | } | |
1202 | if (unlikely(vq->log_used)) { | |
1203 | /* Log used index update. */ | |
1204 | log_write(vq->log_base, | |
1205 | vq->log_addr + offsetof(struct vring_used, idx), | |
1206 | sizeof vq->used->idx); | |
1207 | if (vq->log_ctx) | |
1208 | eventfd_signal(vq->log_ctx, 1); | |
1209 | } | |
1210 | return r; | |
1211 | } | |
1212 | ||
3a4d5c94 MT |
1213 | /* This actually signals the guest, using eventfd. */ |
1214 | void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq) | |
1215 | { | |
0d499356 MT |
1216 | __u16 flags; |
1217 | /* Flush out used index updates. This is paired | |
1218 | * with the barrier that the Guest executes when enabling | |
1219 | * interrupts. */ | |
1220 | smp_mb(); | |
1221 | ||
3a4d5c94 MT |
1222 | if (get_user(flags, &vq->avail->flags)) { |
1223 | vq_err(vq, "Failed to get flags"); | |
1224 | return; | |
1225 | } | |
1226 | ||
1227 | /* If they don't want an interrupt, don't signal, unless empty. */ | |
1228 | if ((flags & VRING_AVAIL_F_NO_INTERRUPT) && | |
1229 | (vq->avail_idx != vq->last_avail_idx || | |
1230 | !vhost_has_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY))) | |
1231 | return; | |
1232 | ||
1233 | /* Signal the Guest tell them we used something up. */ | |
1234 | if (vq->call_ctx) | |
1235 | eventfd_signal(vq->call_ctx, 1); | |
1236 | } | |
1237 | ||
1238 | /* And here's the combo meal deal. Supersize me! */ | |
1239 | void vhost_add_used_and_signal(struct vhost_dev *dev, | |
1240 | struct vhost_virtqueue *vq, | |
1241 | unsigned int head, int len) | |
1242 | { | |
1243 | vhost_add_used(vq, head, len); | |
1244 | vhost_signal(dev, vq); | |
1245 | } | |
1246 | ||
8dd014ad DS |
1247 | /* multi-buffer version of vhost_add_used_and_signal */ |
1248 | void vhost_add_used_and_signal_n(struct vhost_dev *dev, | |
1249 | struct vhost_virtqueue *vq, | |
1250 | struct vring_used_elem *heads, unsigned count) | |
1251 | { | |
1252 | vhost_add_used_n(vq, heads, count); | |
1253 | vhost_signal(dev, vq); | |
1254 | } | |
1255 | ||
3a4d5c94 MT |
1256 | /* OK, now we need to know about added descriptors. */ |
1257 | bool vhost_enable_notify(struct vhost_virtqueue *vq) | |
1258 | { | |
1259 | u16 avail_idx; | |
1260 | int r; | |
1261 | if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY)) | |
1262 | return false; | |
1263 | vq->used_flags &= ~VRING_USED_F_NO_NOTIFY; | |
1264 | r = put_user(vq->used_flags, &vq->used->flags); | |
1265 | if (r) { | |
1266 | vq_err(vq, "Failed to enable notification at %p: %d\n", | |
1267 | &vq->used->flags, r); | |
1268 | return false; | |
1269 | } | |
1270 | /* They could have slipped one in as we were doing that: make | |
1271 | * sure it's written, then check again. */ | |
5659338c | 1272 | smp_mb(); |
3a4d5c94 MT |
1273 | r = get_user(avail_idx, &vq->avail->idx); |
1274 | if (r) { | |
1275 | vq_err(vq, "Failed to check avail idx at %p: %d\n", | |
1276 | &vq->avail->idx, r); | |
1277 | return false; | |
1278 | } | |
1279 | ||
8dd014ad | 1280 | return avail_idx != vq->avail_idx; |
3a4d5c94 MT |
1281 | } |
1282 | ||
1283 | /* We don't need to be notified again. */ | |
1284 | void vhost_disable_notify(struct vhost_virtqueue *vq) | |
1285 | { | |
1286 | int r; | |
1287 | if (vq->used_flags & VRING_USED_F_NO_NOTIFY) | |
1288 | return; | |
1289 | vq->used_flags |= VRING_USED_F_NO_NOTIFY; | |
1290 | r = put_user(vq->used_flags, &vq->used->flags); | |
1291 | if (r) | |
1292 | vq_err(vq, "Failed to enable notification at %p: %d\n", | |
1293 | &vq->used->flags, r); | |
1294 | } |