Commit | Line | Data |
---|---|---|
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> | |
20 | #include <linux/workqueue.h> | |
21 | #include <linux/rcupdate.h> | |
22 | #include <linux/poll.h> | |
23 | #include <linux/file.h> | |
24 | #include <linux/highmem.h> | |
25 | ||
26 | #include <linux/net.h> | |
27 | #include <linux/if_packet.h> | |
28 | #include <linux/if_arp.h> | |
29 | ||
30 | #include <net/sock.h> | |
31 | ||
32 | #include "vhost.h" | |
33 | ||
34 | enum { | |
35 | VHOST_MEMORY_MAX_NREGIONS = 64, | |
36 | VHOST_MEMORY_F_LOG = 0x1, | |
37 | }; | |
38 | ||
39 | static struct workqueue_struct *vhost_workqueue; | |
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 | 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 | { | |
54 | struct vhost_poll *poll; | |
55 | poll = container_of(wait, struct vhost_poll, wait); | |
56 | if (!((unsigned long)key & poll->mask)) | |
57 | return 0; | |
58 | ||
59 | queue_work(vhost_workqueue, &poll->work); | |
60 | return 0; | |
61 | } | |
62 | ||
63 | /* Init poll structure */ | |
64 | void vhost_poll_init(struct vhost_poll *poll, work_func_t func, | |
65 | unsigned long mask) | |
66 | { | |
67 | INIT_WORK(&poll->work, func); | |
68 | init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup); | |
69 | init_poll_funcptr(&poll->table, vhost_poll_func); | |
70 | poll->mask = mask; | |
71 | } | |
72 | ||
73 | /* Start polling a file. We add ourselves to file's wait queue. The caller must | |
74 | * keep a reference to a file until after vhost_poll_stop is called. */ | |
75 | void vhost_poll_start(struct vhost_poll *poll, struct file *file) | |
76 | { | |
77 | unsigned long mask; | |
78 | mask = file->f_op->poll(file, &poll->table); | |
79 | if (mask) | |
80 | vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask); | |
81 | } | |
82 | ||
83 | /* Stop polling a file. After this function returns, it becomes safe to drop the | |
84 | * file reference. You must also flush afterwards. */ | |
85 | void vhost_poll_stop(struct vhost_poll *poll) | |
86 | { | |
87 | remove_wait_queue(poll->wqh, &poll->wait); | |
88 | } | |
89 | ||
90 | /* Flush any work that has been scheduled. When calling this, don't hold any | |
91 | * locks that are also used by the callback. */ | |
92 | void vhost_poll_flush(struct vhost_poll *poll) | |
93 | { | |
94 | flush_work(&poll->work); | |
95 | } | |
96 | ||
97 | void vhost_poll_queue(struct vhost_poll *poll) | |
98 | { | |
99 | queue_work(vhost_workqueue, &poll->work); | |
100 | } | |
101 | ||
102 | static void vhost_vq_reset(struct vhost_dev *dev, | |
103 | struct vhost_virtqueue *vq) | |
104 | { | |
105 | vq->num = 1; | |
106 | vq->desc = NULL; | |
107 | vq->avail = NULL; | |
108 | vq->used = NULL; | |
109 | vq->last_avail_idx = 0; | |
110 | vq->avail_idx = 0; | |
111 | vq->last_used_idx = 0; | |
112 | vq->used_flags = 0; | |
113 | vq->used_flags = 0; | |
114 | vq->log_used = false; | |
115 | vq->log_addr = -1ull; | |
116 | vq->hdr_size = 0; | |
117 | vq->private_data = NULL; | |
118 | vq->log_base = NULL; | |
119 | vq->error_ctx = NULL; | |
120 | vq->error = NULL; | |
121 | vq->kick = NULL; | |
122 | vq->call_ctx = NULL; | |
123 | vq->call = NULL; | |
124 | } | |
125 | ||
126 | long vhost_dev_init(struct vhost_dev *dev, | |
127 | struct vhost_virtqueue *vqs, int nvqs) | |
128 | { | |
129 | int i; | |
130 | dev->vqs = vqs; | |
131 | dev->nvqs = nvqs; | |
132 | mutex_init(&dev->mutex); | |
133 | dev->log_ctx = NULL; | |
134 | dev->log_file = NULL; | |
135 | dev->memory = NULL; | |
136 | dev->mm = NULL; | |
137 | ||
138 | for (i = 0; i < dev->nvqs; ++i) { | |
139 | dev->vqs[i].dev = dev; | |
140 | mutex_init(&dev->vqs[i].mutex); | |
141 | vhost_vq_reset(dev, dev->vqs + i); | |
142 | if (dev->vqs[i].handle_kick) | |
143 | vhost_poll_init(&dev->vqs[i].poll, | |
144 | dev->vqs[i].handle_kick, | |
145 | POLLIN); | |
146 | } | |
147 | return 0; | |
148 | } | |
149 | ||
150 | /* Caller should have device mutex */ | |
151 | long vhost_dev_check_owner(struct vhost_dev *dev) | |
152 | { | |
153 | /* Are you the owner? If not, I don't think you mean to do that */ | |
154 | return dev->mm == current->mm ? 0 : -EPERM; | |
155 | } | |
156 | ||
157 | /* Caller should have device mutex */ | |
158 | static long vhost_dev_set_owner(struct vhost_dev *dev) | |
159 | { | |
160 | /* Is there an owner already? */ | |
161 | if (dev->mm) | |
162 | return -EBUSY; | |
163 | /* No owner, become one */ | |
164 | dev->mm = get_task_mm(current); | |
165 | return 0; | |
166 | } | |
167 | ||
168 | /* Caller should have device mutex */ | |
169 | long vhost_dev_reset_owner(struct vhost_dev *dev) | |
170 | { | |
171 | struct vhost_memory *memory; | |
172 | ||
173 | /* Restore memory to default empty mapping. */ | |
174 | memory = kmalloc(offsetof(struct vhost_memory, regions), GFP_KERNEL); | |
175 | if (!memory) | |
176 | return -ENOMEM; | |
177 | ||
178 | vhost_dev_cleanup(dev); | |
179 | ||
180 | memory->nregions = 0; | |
181 | dev->memory = memory; | |
182 | return 0; | |
183 | } | |
184 | ||
185 | /* Caller should have device mutex */ | |
186 | void vhost_dev_cleanup(struct vhost_dev *dev) | |
187 | { | |
188 | int i; | |
189 | for (i = 0; i < dev->nvqs; ++i) { | |
190 | if (dev->vqs[i].kick && dev->vqs[i].handle_kick) { | |
191 | vhost_poll_stop(&dev->vqs[i].poll); | |
192 | vhost_poll_flush(&dev->vqs[i].poll); | |
193 | } | |
194 | if (dev->vqs[i].error_ctx) | |
195 | eventfd_ctx_put(dev->vqs[i].error_ctx); | |
196 | if (dev->vqs[i].error) | |
197 | fput(dev->vqs[i].error); | |
198 | if (dev->vqs[i].kick) | |
199 | fput(dev->vqs[i].kick); | |
200 | if (dev->vqs[i].call_ctx) | |
201 | eventfd_ctx_put(dev->vqs[i].call_ctx); | |
202 | if (dev->vqs[i].call) | |
203 | fput(dev->vqs[i].call); | |
204 | vhost_vq_reset(dev, dev->vqs + i); | |
205 | } | |
206 | if (dev->log_ctx) | |
207 | eventfd_ctx_put(dev->log_ctx); | |
208 | dev->log_ctx = NULL; | |
209 | if (dev->log_file) | |
210 | fput(dev->log_file); | |
211 | dev->log_file = NULL; | |
212 | /* No one will access memory at this point */ | |
213 | kfree(dev->memory); | |
214 | dev->memory = NULL; | |
215 | if (dev->mm) | |
216 | mmput(dev->mm); | |
217 | dev->mm = NULL; | |
218 | } | |
219 | ||
220 | static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz) | |
221 | { | |
222 | u64 a = addr / VHOST_PAGE_SIZE / 8; | |
223 | /* Make sure 64 bit math will not overflow. */ | |
224 | if (a > ULONG_MAX - (unsigned long)log_base || | |
225 | a + (unsigned long)log_base > ULONG_MAX) | |
226 | return -EFAULT; | |
227 | ||
228 | return access_ok(VERIFY_WRITE, log_base + a, | |
229 | (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8); | |
230 | } | |
231 | ||
232 | /* Caller should have vq mutex and device mutex. */ | |
233 | static int vq_memory_access_ok(void __user *log_base, struct vhost_memory *mem, | |
234 | int log_all) | |
235 | { | |
236 | int i; | |
237 | for (i = 0; i < mem->nregions; ++i) { | |
238 | struct vhost_memory_region *m = mem->regions + i; | |
239 | unsigned long a = m->userspace_addr; | |
240 | if (m->memory_size > ULONG_MAX) | |
241 | return 0; | |
242 | else if (!access_ok(VERIFY_WRITE, (void __user *)a, | |
243 | m->memory_size)) | |
244 | return 0; | |
245 | else if (log_all && !log_access_ok(log_base, | |
246 | m->guest_phys_addr, | |
247 | m->memory_size)) | |
248 | return 0; | |
249 | } | |
250 | return 1; | |
251 | } | |
252 | ||
253 | /* Can we switch to this memory table? */ | |
254 | /* Caller should have device mutex but not vq mutex */ | |
255 | static int memory_access_ok(struct vhost_dev *d, struct vhost_memory *mem, | |
256 | int log_all) | |
257 | { | |
258 | int i; | |
259 | for (i = 0; i < d->nvqs; ++i) { | |
260 | int ok; | |
261 | mutex_lock(&d->vqs[i].mutex); | |
262 | /* If ring is inactive, will check when it's enabled. */ | |
263 | if (d->vqs[i].private_data) | |
264 | ok = vq_memory_access_ok(d->vqs[i].log_base, mem, | |
265 | log_all); | |
266 | else | |
267 | ok = 1; | |
268 | mutex_unlock(&d->vqs[i].mutex); | |
269 | if (!ok) | |
270 | return 0; | |
271 | } | |
272 | return 1; | |
273 | } | |
274 | ||
275 | static int vq_access_ok(unsigned int num, | |
276 | struct vring_desc __user *desc, | |
277 | struct vring_avail __user *avail, | |
278 | struct vring_used __user *used) | |
279 | { | |
280 | return access_ok(VERIFY_READ, desc, num * sizeof *desc) && | |
281 | access_ok(VERIFY_READ, avail, | |
282 | sizeof *avail + num * sizeof *avail->ring) && | |
283 | access_ok(VERIFY_WRITE, used, | |
284 | sizeof *used + num * sizeof *used->ring); | |
285 | } | |
286 | ||
287 | /* Can we log writes? */ | |
288 | /* Caller should have device mutex but not vq mutex */ | |
289 | int vhost_log_access_ok(struct vhost_dev *dev) | |
290 | { | |
291 | return memory_access_ok(dev, dev->memory, 1); | |
292 | } | |
293 | ||
294 | /* Verify access for write logging. */ | |
295 | /* Caller should have vq mutex and device mutex */ | |
296 | static int vq_log_access_ok(struct vhost_virtqueue *vq, void __user *log_base) | |
297 | { | |
298 | return vq_memory_access_ok(log_base, vq->dev->memory, | |
299 | vhost_has_feature(vq->dev, VHOST_F_LOG_ALL)) && | |
300 | (!vq->log_used || log_access_ok(log_base, vq->log_addr, | |
301 | sizeof *vq->used + | |
302 | vq->num * sizeof *vq->used->ring)); | |
303 | } | |
304 | ||
305 | /* Can we start vq? */ | |
306 | /* Caller should have vq mutex and device mutex */ | |
307 | int vhost_vq_access_ok(struct vhost_virtqueue *vq) | |
308 | { | |
309 | return vq_access_ok(vq->num, vq->desc, vq->avail, vq->used) && | |
310 | vq_log_access_ok(vq, vq->log_base); | |
311 | } | |
312 | ||
313 | static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) | |
314 | { | |
315 | struct vhost_memory mem, *newmem, *oldmem; | |
316 | unsigned long size = offsetof(struct vhost_memory, regions); | |
317 | long r; | |
318 | r = copy_from_user(&mem, m, size); | |
319 | if (r) | |
320 | return r; | |
321 | if (mem.padding) | |
322 | return -EOPNOTSUPP; | |
323 | if (mem.nregions > VHOST_MEMORY_MAX_NREGIONS) | |
324 | return -E2BIG; | |
325 | newmem = kmalloc(size + mem.nregions * sizeof *m->regions, GFP_KERNEL); | |
326 | if (!newmem) | |
327 | return -ENOMEM; | |
328 | ||
329 | memcpy(newmem, &mem, size); | |
330 | r = copy_from_user(newmem->regions, m->regions, | |
331 | mem.nregions * sizeof *m->regions); | |
332 | if (r) { | |
333 | kfree(newmem); | |
334 | return r; | |
335 | } | |
336 | ||
337 | if (!memory_access_ok(d, newmem, vhost_has_feature(d, VHOST_F_LOG_ALL))) | |
338 | return -EFAULT; | |
339 | oldmem = d->memory; | |
340 | rcu_assign_pointer(d->memory, newmem); | |
341 | synchronize_rcu(); | |
342 | kfree(oldmem); | |
343 | return 0; | |
344 | } | |
345 | ||
346 | static int init_used(struct vhost_virtqueue *vq, | |
347 | struct vring_used __user *used) | |
348 | { | |
349 | int r = put_user(vq->used_flags, &used->flags); | |
350 | if (r) | |
351 | return r; | |
352 | return get_user(vq->last_used_idx, &used->idx); | |
353 | } | |
354 | ||
355 | static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp) | |
356 | { | |
357 | struct file *eventfp, *filep = NULL, | |
358 | *pollstart = NULL, *pollstop = NULL; | |
359 | struct eventfd_ctx *ctx = NULL; | |
360 | u32 __user *idxp = argp; | |
361 | struct vhost_virtqueue *vq; | |
362 | struct vhost_vring_state s; | |
363 | struct vhost_vring_file f; | |
364 | struct vhost_vring_addr a; | |
365 | u32 idx; | |
366 | long r; | |
367 | ||
368 | r = get_user(idx, idxp); | |
369 | if (r < 0) | |
370 | return r; | |
371 | if (idx > d->nvqs) | |
372 | return -ENOBUFS; | |
373 | ||
374 | vq = d->vqs + idx; | |
375 | ||
376 | mutex_lock(&vq->mutex); | |
377 | ||
378 | switch (ioctl) { | |
379 | case VHOST_SET_VRING_NUM: | |
380 | /* Resizing ring with an active backend? | |
381 | * You don't want to do that. */ | |
382 | if (vq->private_data) { | |
383 | r = -EBUSY; | |
384 | break; | |
385 | } | |
386 | r = copy_from_user(&s, argp, sizeof s); | |
387 | if (r < 0) | |
388 | break; | |
389 | if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) { | |
390 | r = -EINVAL; | |
391 | break; | |
392 | } | |
393 | vq->num = s.num; | |
394 | break; | |
395 | case VHOST_SET_VRING_BASE: | |
396 | /* Moving base with an active backend? | |
397 | * You don't want to do that. */ | |
398 | if (vq->private_data) { | |
399 | r = -EBUSY; | |
400 | break; | |
401 | } | |
402 | r = copy_from_user(&s, argp, sizeof s); | |
403 | if (r < 0) | |
404 | break; | |
405 | if (s.num > 0xffff) { | |
406 | r = -EINVAL; | |
407 | break; | |
408 | } | |
409 | vq->last_avail_idx = s.num; | |
410 | /* Forget the cached index value. */ | |
411 | vq->avail_idx = vq->last_avail_idx; | |
412 | break; | |
413 | case VHOST_GET_VRING_BASE: | |
414 | s.index = idx; | |
415 | s.num = vq->last_avail_idx; | |
416 | r = copy_to_user(argp, &s, sizeof s); | |
417 | break; | |
418 | case VHOST_SET_VRING_ADDR: | |
419 | r = copy_from_user(&a, argp, sizeof a); | |
420 | if (r < 0) | |
421 | break; | |
422 | if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) { | |
423 | r = -EOPNOTSUPP; | |
424 | break; | |
425 | } | |
426 | /* For 32bit, verify that the top 32bits of the user | |
427 | data are set to zero. */ | |
428 | if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr || | |
429 | (u64)(unsigned long)a.used_user_addr != a.used_user_addr || | |
430 | (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) { | |
431 | r = -EFAULT; | |
432 | break; | |
433 | } | |
434 | if ((a.avail_user_addr & (sizeof *vq->avail->ring - 1)) || | |
435 | (a.used_user_addr & (sizeof *vq->used->ring - 1)) || | |
436 | (a.log_guest_addr & (sizeof *vq->used->ring - 1))) { | |
437 | r = -EINVAL; | |
438 | break; | |
439 | } | |
440 | ||
441 | /* We only verify access here if backend is configured. | |
442 | * If it is not, we don't as size might not have been setup. | |
443 | * We will verify when backend is configured. */ | |
444 | if (vq->private_data) { | |
445 | if (!vq_access_ok(vq->num, | |
446 | (void __user *)(unsigned long)a.desc_user_addr, | |
447 | (void __user *)(unsigned long)a.avail_user_addr, | |
448 | (void __user *)(unsigned long)a.used_user_addr)) { | |
449 | r = -EINVAL; | |
450 | break; | |
451 | } | |
452 | ||
453 | /* Also validate log access for used ring if enabled. */ | |
454 | if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) && | |
455 | !log_access_ok(vq->log_base, a.log_guest_addr, | |
456 | sizeof *vq->used + | |
457 | vq->num * sizeof *vq->used->ring)) { | |
458 | r = -EINVAL; | |
459 | break; | |
460 | } | |
461 | } | |
462 | ||
463 | r = init_used(vq, (struct vring_used __user *)(unsigned long) | |
464 | a.used_user_addr); | |
465 | if (r) | |
466 | break; | |
467 | vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG)); | |
468 | vq->desc = (void __user *)(unsigned long)a.desc_user_addr; | |
469 | vq->avail = (void __user *)(unsigned long)a.avail_user_addr; | |
470 | vq->log_addr = a.log_guest_addr; | |
471 | vq->used = (void __user *)(unsigned long)a.used_user_addr; | |
472 | break; | |
473 | case VHOST_SET_VRING_KICK: | |
474 | r = copy_from_user(&f, argp, sizeof f); | |
475 | if (r < 0) | |
476 | break; | |
477 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); | |
478 | if (IS_ERR(eventfp)) | |
479 | return PTR_ERR(eventfp); | |
480 | if (eventfp != vq->kick) { | |
481 | pollstop = filep = vq->kick; | |
482 | pollstart = vq->kick = eventfp; | |
483 | } else | |
484 | filep = eventfp; | |
485 | break; | |
486 | case VHOST_SET_VRING_CALL: | |
487 | r = copy_from_user(&f, argp, sizeof f); | |
488 | if (r < 0) | |
489 | break; | |
490 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); | |
491 | if (IS_ERR(eventfp)) | |
492 | return PTR_ERR(eventfp); | |
493 | if (eventfp != vq->call) { | |
494 | filep = vq->call; | |
495 | ctx = vq->call_ctx; | |
496 | vq->call = eventfp; | |
497 | vq->call_ctx = eventfp ? | |
498 | eventfd_ctx_fileget(eventfp) : NULL; | |
499 | } else | |
500 | filep = eventfp; | |
501 | break; | |
502 | case VHOST_SET_VRING_ERR: | |
503 | r = copy_from_user(&f, argp, sizeof f); | |
504 | if (r < 0) | |
505 | break; | |
506 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); | |
507 | if (IS_ERR(eventfp)) | |
508 | return PTR_ERR(eventfp); | |
509 | if (eventfp != vq->error) { | |
510 | filep = vq->error; | |
511 | vq->error = eventfp; | |
512 | ctx = vq->error_ctx; | |
513 | vq->error_ctx = eventfp ? | |
514 | eventfd_ctx_fileget(eventfp) : NULL; | |
515 | } else | |
516 | filep = eventfp; | |
517 | break; | |
518 | default: | |
519 | r = -ENOIOCTLCMD; | |
520 | } | |
521 | ||
522 | if (pollstop && vq->handle_kick) | |
523 | vhost_poll_stop(&vq->poll); | |
524 | ||
525 | if (ctx) | |
526 | eventfd_ctx_put(ctx); | |
527 | if (filep) | |
528 | fput(filep); | |
529 | ||
530 | if (pollstart && vq->handle_kick) | |
531 | vhost_poll_start(&vq->poll, vq->kick); | |
532 | ||
533 | mutex_unlock(&vq->mutex); | |
534 | ||
535 | if (pollstop && vq->handle_kick) | |
536 | vhost_poll_flush(&vq->poll); | |
537 | return r; | |
538 | } | |
539 | ||
540 | /* Caller must have device mutex */ | |
541 | long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, unsigned long arg) | |
542 | { | |
543 | void __user *argp = (void __user *)arg; | |
544 | struct file *eventfp, *filep = NULL; | |
545 | struct eventfd_ctx *ctx = NULL; | |
546 | u64 p; | |
547 | long r; | |
548 | int i, fd; | |
549 | ||
550 | /* If you are not the owner, you can become one */ | |
551 | if (ioctl == VHOST_SET_OWNER) { | |
552 | r = vhost_dev_set_owner(d); | |
553 | goto done; | |
554 | } | |
555 | ||
556 | /* You must be the owner to do anything else */ | |
557 | r = vhost_dev_check_owner(d); | |
558 | if (r) | |
559 | goto done; | |
560 | ||
561 | switch (ioctl) { | |
562 | case VHOST_SET_MEM_TABLE: | |
563 | r = vhost_set_memory(d, argp); | |
564 | break; | |
565 | case VHOST_SET_LOG_BASE: | |
566 | r = copy_from_user(&p, argp, sizeof p); | |
567 | if (r < 0) | |
568 | break; | |
569 | if ((u64)(unsigned long)p != p) { | |
570 | r = -EFAULT; | |
571 | break; | |
572 | } | |
573 | for (i = 0; i < d->nvqs; ++i) { | |
574 | struct vhost_virtqueue *vq; | |
575 | void __user *base = (void __user *)(unsigned long)p; | |
576 | vq = d->vqs + i; | |
577 | mutex_lock(&vq->mutex); | |
578 | /* If ring is inactive, will check when it's enabled. */ | |
579 | if (vq->private_data && !vq_log_access_ok(vq, base)) | |
580 | r = -EFAULT; | |
581 | else | |
582 | vq->log_base = base; | |
583 | mutex_unlock(&vq->mutex); | |
584 | } | |
585 | break; | |
586 | case VHOST_SET_LOG_FD: | |
587 | r = get_user(fd, (int __user *)argp); | |
588 | if (r < 0) | |
589 | break; | |
590 | eventfp = fd == -1 ? NULL : eventfd_fget(fd); | |
591 | if (IS_ERR(eventfp)) { | |
592 | r = PTR_ERR(eventfp); | |
593 | break; | |
594 | } | |
595 | if (eventfp != d->log_file) { | |
596 | filep = d->log_file; | |
597 | ctx = d->log_ctx; | |
598 | d->log_ctx = eventfp ? | |
599 | eventfd_ctx_fileget(eventfp) : NULL; | |
600 | } else | |
601 | filep = eventfp; | |
602 | for (i = 0; i < d->nvqs; ++i) { | |
603 | mutex_lock(&d->vqs[i].mutex); | |
604 | d->vqs[i].log_ctx = d->log_ctx; | |
605 | mutex_unlock(&d->vqs[i].mutex); | |
606 | } | |
607 | if (ctx) | |
608 | eventfd_ctx_put(ctx); | |
609 | if (filep) | |
610 | fput(filep); | |
611 | break; | |
612 | default: | |
613 | r = vhost_set_vring(d, ioctl, argp); | |
614 | break; | |
615 | } | |
616 | done: | |
617 | return r; | |
618 | } | |
619 | ||
620 | static const struct vhost_memory_region *find_region(struct vhost_memory *mem, | |
621 | __u64 addr, __u32 len) | |
622 | { | |
623 | struct vhost_memory_region *reg; | |
624 | int i; | |
625 | /* linear search is not brilliant, but we really have on the order of 6 | |
626 | * regions in practice */ | |
627 | for (i = 0; i < mem->nregions; ++i) { | |
628 | reg = mem->regions + i; | |
629 | if (reg->guest_phys_addr <= addr && | |
630 | reg->guest_phys_addr + reg->memory_size - 1 >= addr) | |
631 | return reg; | |
632 | } | |
633 | return NULL; | |
634 | } | |
635 | ||
636 | /* TODO: This is really inefficient. We need something like get_user() | |
637 | * (instruction directly accesses the data, with an exception table entry | |
638 | * returning -EFAULT). See Documentation/x86/exception-tables.txt. | |
639 | */ | |
640 | static int set_bit_to_user(int nr, void __user *addr) | |
641 | { | |
642 | unsigned long log = (unsigned long)addr; | |
643 | struct page *page; | |
644 | void *base; | |
645 | int bit = nr + (log % PAGE_SIZE) * 8; | |
646 | int r; | |
647 | r = get_user_pages_fast(log, 1, 1, &page); | |
648 | if (r) | |
649 | return r; | |
650 | base = kmap_atomic(page, KM_USER0); | |
651 | set_bit(bit, base); | |
652 | kunmap_atomic(base, KM_USER0); | |
653 | set_page_dirty_lock(page); | |
654 | put_page(page); | |
655 | return 0; | |
656 | } | |
657 | ||
658 | static int log_write(void __user *log_base, | |
659 | u64 write_address, u64 write_length) | |
660 | { | |
661 | int r; | |
662 | if (!write_length) | |
663 | return 0; | |
664 | write_address /= VHOST_PAGE_SIZE; | |
665 | for (;;) { | |
666 | u64 base = (u64)(unsigned long)log_base; | |
667 | u64 log = base + write_address / 8; | |
668 | int bit = write_address % 8; | |
669 | if ((u64)(unsigned long)log != log) | |
670 | return -EFAULT; | |
671 | r = set_bit_to_user(bit, (void __user *)(unsigned long)log); | |
672 | if (r < 0) | |
673 | return r; | |
674 | if (write_length <= VHOST_PAGE_SIZE) | |
675 | break; | |
676 | write_length -= VHOST_PAGE_SIZE; | |
677 | write_address += VHOST_PAGE_SIZE; | |
678 | } | |
679 | return r; | |
680 | } | |
681 | ||
682 | int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, | |
683 | unsigned int log_num, u64 len) | |
684 | { | |
685 | int i, r; | |
686 | ||
687 | /* Make sure data written is seen before log. */ | |
5659338c | 688 | smp_wmb(); |
3a4d5c94 MT |
689 | for (i = 0; i < log_num; ++i) { |
690 | u64 l = min(log[i].len, len); | |
691 | r = log_write(vq->log_base, log[i].addr, l); | |
692 | if (r < 0) | |
693 | return r; | |
694 | len -= l; | |
695 | if (!len) | |
696 | return 0; | |
697 | } | |
698 | if (vq->log_ctx) | |
699 | eventfd_signal(vq->log_ctx, 1); | |
700 | /* Length written exceeds what we have stored. This is a bug. */ | |
701 | BUG(); | |
702 | return 0; | |
703 | } | |
704 | ||
705 | int translate_desc(struct vhost_dev *dev, u64 addr, u32 len, | |
706 | struct iovec iov[], int iov_size) | |
707 | { | |
708 | const struct vhost_memory_region *reg; | |
709 | struct vhost_memory *mem; | |
710 | struct iovec *_iov; | |
711 | u64 s = 0; | |
712 | int ret = 0; | |
713 | ||
714 | rcu_read_lock(); | |
715 | ||
716 | mem = rcu_dereference(dev->memory); | |
717 | while ((u64)len > s) { | |
718 | u64 size; | |
719 | if (ret >= iov_size) { | |
720 | ret = -ENOBUFS; | |
721 | break; | |
722 | } | |
723 | reg = find_region(mem, addr, len); | |
724 | if (!reg) { | |
725 | ret = -EFAULT; | |
726 | break; | |
727 | } | |
728 | _iov = iov + ret; | |
729 | size = reg->memory_size - addr + reg->guest_phys_addr; | |
730 | _iov->iov_len = min((u64)len, size); | |
731 | _iov->iov_base = (void *)(unsigned long) | |
732 | (reg->userspace_addr + addr - reg->guest_phys_addr); | |
733 | s += size; | |
734 | addr += size; | |
735 | ++ret; | |
736 | } | |
737 | ||
738 | rcu_read_unlock(); | |
739 | return ret; | |
740 | } | |
741 | ||
742 | /* Each buffer in the virtqueues is actually a chain of descriptors. This | |
743 | * function returns the next descriptor in the chain, | |
744 | * or -1U if we're at the end. */ | |
745 | static unsigned next_desc(struct vring_desc *desc) | |
746 | { | |
747 | unsigned int next; | |
748 | ||
749 | /* If this descriptor says it doesn't chain, we're done. */ | |
750 | if (!(desc->flags & VRING_DESC_F_NEXT)) | |
751 | return -1U; | |
752 | ||
753 | /* Check they're not leading us off end of descriptors. */ | |
754 | next = desc->next; | |
755 | /* Make sure compiler knows to grab that: we don't want it changing! */ | |
756 | /* We will use the result as an index in an array, so most | |
757 | * architectures only need a compiler barrier here. */ | |
758 | read_barrier_depends(); | |
759 | ||
760 | return next; | |
761 | } | |
762 | ||
763 | static unsigned get_indirect(struct vhost_dev *dev, struct vhost_virtqueue *vq, | |
764 | struct iovec iov[], unsigned int iov_size, | |
765 | unsigned int *out_num, unsigned int *in_num, | |
766 | struct vhost_log *log, unsigned int *log_num, | |
767 | struct vring_desc *indirect) | |
768 | { | |
769 | struct vring_desc desc; | |
770 | unsigned int i = 0, count, found = 0; | |
771 | int ret; | |
772 | ||
773 | /* Sanity check */ | |
774 | if (indirect->len % sizeof desc) { | |
775 | vq_err(vq, "Invalid length in indirect descriptor: " | |
776 | "len 0x%llx not multiple of 0x%zx\n", | |
777 | (unsigned long long)indirect->len, | |
778 | sizeof desc); | |
779 | return -EINVAL; | |
780 | } | |
781 | ||
782 | ret = translate_desc(dev, indirect->addr, indirect->len, vq->indirect, | |
783 | ARRAY_SIZE(vq->indirect)); | |
784 | if (ret < 0) { | |
785 | vq_err(vq, "Translation failure %d in indirect.\n", ret); | |
786 | return ret; | |
787 | } | |
788 | ||
789 | /* We will use the result as an address to read from, so most | |
790 | * architectures only need a compiler barrier here. */ | |
791 | read_barrier_depends(); | |
792 | ||
793 | count = indirect->len / sizeof desc; | |
794 | /* Buffers are chained via a 16 bit next field, so | |
795 | * we can have at most 2^16 of these. */ | |
796 | if (count > USHORT_MAX + 1) { | |
797 | vq_err(vq, "Indirect buffer length too big: %d\n", | |
798 | indirect->len); | |
799 | return -E2BIG; | |
800 | } | |
801 | ||
802 | do { | |
803 | unsigned iov_count = *in_num + *out_num; | |
804 | if (++found > count) { | |
805 | vq_err(vq, "Loop detected: last one at %u " | |
806 | "indirect size %u\n", | |
807 | i, count); | |
808 | return -EINVAL; | |
809 | } | |
810 | if (memcpy_fromiovec((unsigned char *)&desc, vq->indirect, | |
811 | sizeof desc)) { | |
812 | vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n", | |
813 | i, (size_t)indirect->addr + i * sizeof desc); | |
814 | return -EINVAL; | |
815 | } | |
816 | if (desc.flags & VRING_DESC_F_INDIRECT) { | |
817 | vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n", | |
818 | i, (size_t)indirect->addr + i * sizeof desc); | |
819 | return -EINVAL; | |
820 | } | |
821 | ||
822 | ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, | |
823 | iov_size - iov_count); | |
824 | if (ret < 0) { | |
825 | vq_err(vq, "Translation failure %d indirect idx %d\n", | |
826 | ret, i); | |
827 | return ret; | |
828 | } | |
829 | /* If this is an input descriptor, increment that count. */ | |
830 | if (desc.flags & VRING_DESC_F_WRITE) { | |
831 | *in_num += ret; | |
832 | if (unlikely(log)) { | |
833 | log[*log_num].addr = desc.addr; | |
834 | log[*log_num].len = desc.len; | |
835 | ++*log_num; | |
836 | } | |
837 | } else { | |
838 | /* If it's an output descriptor, they're all supposed | |
839 | * to come before any input descriptors. */ | |
840 | if (*in_num) { | |
841 | vq_err(vq, "Indirect descriptor " | |
842 | "has out after in: idx %d\n", i); | |
843 | return -EINVAL; | |
844 | } | |
845 | *out_num += ret; | |
846 | } | |
847 | } while ((i = next_desc(&desc)) != -1); | |
848 | return 0; | |
849 | } | |
850 | ||
851 | /* This looks in the virtqueue and for the first available buffer, and converts | |
852 | * it to an iovec for convenient access. Since descriptors consist of some | |
853 | * number of output then some number of input descriptors, it's actually two | |
854 | * iovecs, but we pack them into one and note how many of each there were. | |
855 | * | |
856 | * This function returns the descriptor number found, or vq->num (which | |
857 | * is never a valid descriptor number) if none was found. */ | |
858 | unsigned vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq, | |
859 | struct iovec iov[], unsigned int iov_size, | |
860 | unsigned int *out_num, unsigned int *in_num, | |
861 | struct vhost_log *log, unsigned int *log_num) | |
862 | { | |
863 | struct vring_desc desc; | |
864 | unsigned int i, head, found = 0; | |
865 | u16 last_avail_idx; | |
866 | int ret; | |
867 | ||
868 | /* Check it isn't doing very strange things with descriptor numbers. */ | |
869 | last_avail_idx = vq->last_avail_idx; | |
870 | if (get_user(vq->avail_idx, &vq->avail->idx)) { | |
871 | vq_err(vq, "Failed to access avail idx at %p\n", | |
872 | &vq->avail->idx); | |
873 | return vq->num; | |
874 | } | |
875 | ||
876 | if ((u16)(vq->avail_idx - last_avail_idx) > vq->num) { | |
877 | vq_err(vq, "Guest moved used index from %u to %u", | |
878 | last_avail_idx, vq->avail_idx); | |
879 | return vq->num; | |
880 | } | |
881 | ||
882 | /* If there's nothing new since last we looked, return invalid. */ | |
883 | if (vq->avail_idx == last_avail_idx) | |
884 | return vq->num; | |
885 | ||
886 | /* Only get avail ring entries after they have been exposed by guest. */ | |
5659338c | 887 | smp_rmb(); |
3a4d5c94 MT |
888 | |
889 | /* Grab the next descriptor number they're advertising, and increment | |
890 | * the index we've seen. */ | |
891 | if (get_user(head, &vq->avail->ring[last_avail_idx % vq->num])) { | |
892 | vq_err(vq, "Failed to read head: idx %d address %p\n", | |
893 | last_avail_idx, | |
894 | &vq->avail->ring[last_avail_idx % vq->num]); | |
895 | return vq->num; | |
896 | } | |
897 | ||
898 | /* If their number is silly, that's an error. */ | |
899 | if (head >= vq->num) { | |
900 | vq_err(vq, "Guest says index %u > %u is available", | |
901 | head, vq->num); | |
902 | return vq->num; | |
903 | } | |
904 | ||
905 | /* When we start there are none of either input nor output. */ | |
906 | *out_num = *in_num = 0; | |
907 | if (unlikely(log)) | |
908 | *log_num = 0; | |
909 | ||
910 | i = head; | |
911 | do { | |
912 | unsigned iov_count = *in_num + *out_num; | |
913 | if (i >= vq->num) { | |
914 | vq_err(vq, "Desc index is %u > %u, head = %u", | |
915 | i, vq->num, head); | |
916 | return vq->num; | |
917 | } | |
918 | if (++found > vq->num) { | |
919 | vq_err(vq, "Loop detected: last one at %u " | |
920 | "vq size %u head %u\n", | |
921 | i, vq->num, head); | |
922 | return vq->num; | |
923 | } | |
924 | ret = copy_from_user(&desc, vq->desc + i, sizeof desc); | |
925 | if (ret) { | |
926 | vq_err(vq, "Failed to get descriptor: idx %d addr %p\n", | |
927 | i, vq->desc + i); | |
928 | return vq->num; | |
929 | } | |
930 | if (desc.flags & VRING_DESC_F_INDIRECT) { | |
931 | ret = get_indirect(dev, vq, iov, iov_size, | |
932 | out_num, in_num, | |
933 | log, log_num, &desc); | |
934 | if (ret < 0) { | |
935 | vq_err(vq, "Failure detected " | |
936 | "in indirect descriptor at idx %d\n", i); | |
937 | return vq->num; | |
938 | } | |
939 | continue; | |
940 | } | |
941 | ||
942 | ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, | |
943 | iov_size - iov_count); | |
944 | if (ret < 0) { | |
945 | vq_err(vq, "Translation failure %d descriptor idx %d\n", | |
946 | ret, i); | |
947 | return vq->num; | |
948 | } | |
949 | if (desc.flags & VRING_DESC_F_WRITE) { | |
950 | /* If this is an input descriptor, | |
951 | * increment that count. */ | |
952 | *in_num += ret; | |
953 | if (unlikely(log)) { | |
954 | log[*log_num].addr = desc.addr; | |
955 | log[*log_num].len = desc.len; | |
956 | ++*log_num; | |
957 | } | |
958 | } else { | |
959 | /* If it's an output descriptor, they're all supposed | |
960 | * to come before any input descriptors. */ | |
961 | if (*in_num) { | |
962 | vq_err(vq, "Descriptor has out after in: " | |
963 | "idx %d\n", i); | |
964 | return vq->num; | |
965 | } | |
966 | *out_num += ret; | |
967 | } | |
968 | } while ((i = next_desc(&desc)) != -1); | |
969 | ||
970 | /* On success, increment avail index. */ | |
971 | vq->last_avail_idx++; | |
972 | return head; | |
973 | } | |
974 | ||
975 | /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */ | |
976 | void vhost_discard_vq_desc(struct vhost_virtqueue *vq) | |
977 | { | |
978 | vq->last_avail_idx--; | |
979 | } | |
980 | ||
981 | /* After we've used one of their buffers, we tell them about it. We'll then | |
982 | * want to notify the guest, using eventfd. */ | |
983 | int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len) | |
984 | { | |
985 | struct vring_used_elem *used; | |
986 | ||
987 | /* The virtqueue contains a ring of used buffers. Get a pointer to the | |
988 | * next entry in that used ring. */ | |
989 | used = &vq->used->ring[vq->last_used_idx % vq->num]; | |
990 | if (put_user(head, &used->id)) { | |
991 | vq_err(vq, "Failed to write used id"); | |
992 | return -EFAULT; | |
993 | } | |
994 | if (put_user(len, &used->len)) { | |
995 | vq_err(vq, "Failed to write used len"); | |
996 | return -EFAULT; | |
997 | } | |
998 | /* Make sure buffer is written before we update index. */ | |
5659338c | 999 | smp_wmb(); |
3a4d5c94 MT |
1000 | if (put_user(vq->last_used_idx + 1, &vq->used->idx)) { |
1001 | vq_err(vq, "Failed to increment used idx"); | |
1002 | return -EFAULT; | |
1003 | } | |
1004 | if (unlikely(vq->log_used)) { | |
1005 | /* Make sure data is seen before log. */ | |
5659338c | 1006 | smp_wmb(); |
3a4d5c94 MT |
1007 | log_write(vq->log_base, vq->log_addr + sizeof *vq->used->ring * |
1008 | (vq->last_used_idx % vq->num), | |
1009 | sizeof *vq->used->ring); | |
1010 | log_write(vq->log_base, vq->log_addr, sizeof *vq->used->ring); | |
1011 | if (vq->log_ctx) | |
1012 | eventfd_signal(vq->log_ctx, 1); | |
1013 | } | |
1014 | vq->last_used_idx++; | |
1015 | return 0; | |
1016 | } | |
1017 | ||
1018 | /* This actually signals the guest, using eventfd. */ | |
1019 | void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq) | |
1020 | { | |
1021 | __u16 flags = 0; | |
1022 | if (get_user(flags, &vq->avail->flags)) { | |
1023 | vq_err(vq, "Failed to get flags"); | |
1024 | return; | |
1025 | } | |
1026 | ||
1027 | /* If they don't want an interrupt, don't signal, unless empty. */ | |
1028 | if ((flags & VRING_AVAIL_F_NO_INTERRUPT) && | |
1029 | (vq->avail_idx != vq->last_avail_idx || | |
1030 | !vhost_has_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY))) | |
1031 | return; | |
1032 | ||
1033 | /* Signal the Guest tell them we used something up. */ | |
1034 | if (vq->call_ctx) | |
1035 | eventfd_signal(vq->call_ctx, 1); | |
1036 | } | |
1037 | ||
1038 | /* And here's the combo meal deal. Supersize me! */ | |
1039 | void vhost_add_used_and_signal(struct vhost_dev *dev, | |
1040 | struct vhost_virtqueue *vq, | |
1041 | unsigned int head, int len) | |
1042 | { | |
1043 | vhost_add_used(vq, head, len); | |
1044 | vhost_signal(dev, vq); | |
1045 | } | |
1046 | ||
1047 | /* OK, now we need to know about added descriptors. */ | |
1048 | bool vhost_enable_notify(struct vhost_virtqueue *vq) | |
1049 | { | |
1050 | u16 avail_idx; | |
1051 | int r; | |
1052 | if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY)) | |
1053 | return false; | |
1054 | vq->used_flags &= ~VRING_USED_F_NO_NOTIFY; | |
1055 | r = put_user(vq->used_flags, &vq->used->flags); | |
1056 | if (r) { | |
1057 | vq_err(vq, "Failed to enable notification at %p: %d\n", | |
1058 | &vq->used->flags, r); | |
1059 | return false; | |
1060 | } | |
1061 | /* They could have slipped one in as we were doing that: make | |
1062 | * sure it's written, then check again. */ | |
5659338c | 1063 | smp_mb(); |
3a4d5c94 MT |
1064 | r = get_user(avail_idx, &vq->avail->idx); |
1065 | if (r) { | |
1066 | vq_err(vq, "Failed to check avail idx at %p: %d\n", | |
1067 | &vq->avail->idx, r); | |
1068 | return false; | |
1069 | } | |
1070 | ||
1071 | return avail_idx != vq->last_avail_idx; | |
1072 | } | |
1073 | ||
1074 | /* We don't need to be notified again. */ | |
1075 | void vhost_disable_notify(struct vhost_virtqueue *vq) | |
1076 | { | |
1077 | int r; | |
1078 | if (vq->used_flags & VRING_USED_F_NO_NOTIFY) | |
1079 | return; | |
1080 | vq->used_flags |= VRING_USED_F_NO_NOTIFY; | |
1081 | r = put_user(vq->used_flags, &vq->used->flags); | |
1082 | if (r) | |
1083 | vq_err(vq, "Failed to enable notification at %p: %d\n", | |
1084 | &vq->used->flags, r); | |
1085 | } | |
1086 | ||
1087 | int vhost_init(void) | |
1088 | { | |
1089 | vhost_workqueue = create_singlethread_workqueue("vhost"); | |
1090 | if (!vhost_workqueue) | |
1091 | return -ENOMEM; | |
1092 | return 0; | |
1093 | } | |
1094 | ||
1095 | void vhost_cleanup(void) | |
1096 | { | |
1097 | destroy_workqueue(vhost_workqueue); | |
1098 | } |