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 | |
61516587 | 7 | * Documentation/virtual/lguest/lguest.c, by Rusty Russell |
3a4d5c94 MT |
8 | * |
9 | * This work is licensed under the terms of the GNU GPL, version 2. | |
10 | * | |
11 | * Generic code for virtio server in host kernel. | |
12 | */ | |
13 | ||
14 | #include <linux/eventfd.h> | |
15 | #include <linux/vhost.h> | |
16 | #include <linux/virtio_net.h> | |
17 | #include <linux/mm.h> | |
64e1c807 | 18 | #include <linux/mmu_context.h> |
3a4d5c94 MT |
19 | #include <linux/miscdevice.h> |
20 | #include <linux/mutex.h> | |
3a4d5c94 MT |
21 | #include <linux/rcupdate.h> |
22 | #include <linux/poll.h> | |
23 | #include <linux/file.h> | |
24 | #include <linux/highmem.h> | |
5a0e3ad6 | 25 | #include <linux/slab.h> |
c23f3445 | 26 | #include <linux/kthread.h> |
9e3d1957 | 27 | #include <linux/cgroup.h> |
3a4d5c94 MT |
28 | |
29 | #include <linux/net.h> | |
30 | #include <linux/if_packet.h> | |
31 | #include <linux/if_arp.h> | |
32 | ||
3a4d5c94 MT |
33 | #include "vhost.h" |
34 | ||
35 | enum { | |
36 | VHOST_MEMORY_MAX_NREGIONS = 64, | |
37 | VHOST_MEMORY_F_LOG = 0x1, | |
38 | }; | |
39 | ||
8ea8cf89 MT |
40 | #define vhost_used_event(vq) ((u16 __user *)&vq->avail->ring[vq->num]) |
41 | #define vhost_avail_event(vq) ((u16 __user *)&vq->used->ring[vq->num]) | |
42 | ||
3a4d5c94 MT |
43 | static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh, |
44 | poll_table *pt) | |
45 | { | |
46 | struct vhost_poll *poll; | |
3a4d5c94 | 47 | |
d47effe1 | 48 | poll = container_of(pt, struct vhost_poll, table); |
3a4d5c94 MT |
49 | poll->wqh = wqh; |
50 | add_wait_queue(wqh, &poll->wait); | |
51 | } | |
52 | ||
53 | static int vhost_poll_wakeup(wait_queue_t *wait, unsigned mode, int sync, | |
54 | void *key) | |
55 | { | |
c23f3445 TH |
56 | struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait); |
57 | ||
3a4d5c94 MT |
58 | if (!((unsigned long)key & poll->mask)) |
59 | return 0; | |
60 | ||
c23f3445 | 61 | vhost_poll_queue(poll); |
3a4d5c94 MT |
62 | return 0; |
63 | } | |
64 | ||
87d6a412 MT |
65 | static void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn) |
66 | { | |
67 | INIT_LIST_HEAD(&work->node); | |
68 | work->fn = fn; | |
69 | init_waitqueue_head(&work->done); | |
70 | work->flushing = 0; | |
71 | work->queue_seq = work->done_seq = 0; | |
72 | } | |
73 | ||
3a4d5c94 | 74 | /* Init poll structure */ |
c23f3445 TH |
75 | void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, |
76 | unsigned long mask, struct vhost_dev *dev) | |
3a4d5c94 | 77 | { |
3a4d5c94 MT |
78 | init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup); |
79 | init_poll_funcptr(&poll->table, vhost_poll_func); | |
80 | poll->mask = mask; | |
c23f3445 TH |
81 | poll->dev = dev; |
82 | ||
87d6a412 | 83 | vhost_work_init(&poll->work, fn); |
3a4d5c94 MT |
84 | } |
85 | ||
86 | /* Start polling a file. We add ourselves to file's wait queue. The caller must | |
87 | * keep a reference to a file until after vhost_poll_stop is called. */ | |
88 | void vhost_poll_start(struct vhost_poll *poll, struct file *file) | |
89 | { | |
90 | unsigned long mask; | |
d47effe1 | 91 | |
3a4d5c94 MT |
92 | mask = file->f_op->poll(file, &poll->table); |
93 | if (mask) | |
94 | vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask); | |
95 | } | |
96 | ||
97 | /* Stop polling a file. After this function returns, it becomes safe to drop the | |
98 | * file reference. You must also flush afterwards. */ | |
99 | void vhost_poll_stop(struct vhost_poll *poll) | |
100 | { | |
101 | remove_wait_queue(poll->wqh, &poll->wait); | |
102 | } | |
103 | ||
0174b0c3 MT |
104 | static bool vhost_work_seq_done(struct vhost_dev *dev, struct vhost_work *work, |
105 | unsigned seq) | |
106 | { | |
107 | int left; | |
d47effe1 | 108 | |
0174b0c3 MT |
109 | spin_lock_irq(&dev->work_lock); |
110 | left = seq - work->done_seq; | |
111 | spin_unlock_irq(&dev->work_lock); | |
112 | return left <= 0; | |
113 | } | |
114 | ||
87d6a412 | 115 | static void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work) |
3a4d5c94 | 116 | { |
c23f3445 | 117 | unsigned seq; |
c23f3445 TH |
118 | int flushing; |
119 | ||
87d6a412 | 120 | spin_lock_irq(&dev->work_lock); |
c23f3445 TH |
121 | seq = work->queue_seq; |
122 | work->flushing++; | |
87d6a412 | 123 | spin_unlock_irq(&dev->work_lock); |
0174b0c3 | 124 | wait_event(work->done, vhost_work_seq_done(dev, work, seq)); |
87d6a412 | 125 | spin_lock_irq(&dev->work_lock); |
c23f3445 | 126 | flushing = --work->flushing; |
87d6a412 | 127 | spin_unlock_irq(&dev->work_lock); |
c23f3445 | 128 | BUG_ON(flushing < 0); |
3a4d5c94 MT |
129 | } |
130 | ||
87d6a412 MT |
131 | /* Flush any work that has been scheduled. When calling this, don't hold any |
132 | * locks that are also used by the callback. */ | |
133 | void vhost_poll_flush(struct vhost_poll *poll) | |
134 | { | |
135 | vhost_work_flush(poll->dev, &poll->work); | |
136 | } | |
137 | ||
138 | static inline void vhost_work_queue(struct vhost_dev *dev, | |
139 | struct vhost_work *work) | |
3a4d5c94 | 140 | { |
c23f3445 TH |
141 | unsigned long flags; |
142 | ||
143 | spin_lock_irqsave(&dev->work_lock, flags); | |
144 | if (list_empty(&work->node)) { | |
145 | list_add_tail(&work->node, &dev->work_list); | |
146 | work->queue_seq++; | |
147 | wake_up_process(dev->worker); | |
148 | } | |
149 | spin_unlock_irqrestore(&dev->work_lock, flags); | |
3a4d5c94 MT |
150 | } |
151 | ||
87d6a412 MT |
152 | void vhost_poll_queue(struct vhost_poll *poll) |
153 | { | |
154 | vhost_work_queue(poll->dev, &poll->work); | |
155 | } | |
156 | ||
3a4d5c94 MT |
157 | static void vhost_vq_reset(struct vhost_dev *dev, |
158 | struct vhost_virtqueue *vq) | |
159 | { | |
160 | vq->num = 1; | |
161 | vq->desc = NULL; | |
162 | vq->avail = NULL; | |
163 | vq->used = NULL; | |
164 | vq->last_avail_idx = 0; | |
165 | vq->avail_idx = 0; | |
166 | vq->last_used_idx = 0; | |
8ea8cf89 MT |
167 | vq->signalled_used = 0; |
168 | vq->signalled_used_valid = false; | |
3a4d5c94 | 169 | vq->used_flags = 0; |
3a4d5c94 MT |
170 | vq->log_used = false; |
171 | vq->log_addr = -1ull; | |
8dd014ad DS |
172 | vq->vhost_hlen = 0; |
173 | vq->sock_hlen = 0; | |
3a4d5c94 MT |
174 | vq->private_data = NULL; |
175 | vq->log_base = NULL; | |
176 | vq->error_ctx = NULL; | |
177 | vq->error = NULL; | |
178 | vq->kick = NULL; | |
179 | vq->call_ctx = NULL; | |
180 | vq->call = NULL; | |
73a99f08 | 181 | vq->log_ctx = NULL; |
3a4d5c94 MT |
182 | } |
183 | ||
c23f3445 TH |
184 | static int vhost_worker(void *data) |
185 | { | |
186 | struct vhost_dev *dev = data; | |
187 | struct vhost_work *work = NULL; | |
188 | unsigned uninitialized_var(seq); | |
189 | ||
64e1c807 MT |
190 | use_mm(dev->mm); |
191 | ||
c23f3445 TH |
192 | for (;;) { |
193 | /* mb paired w/ kthread_stop */ | |
194 | set_current_state(TASK_INTERRUPTIBLE); | |
195 | ||
196 | spin_lock_irq(&dev->work_lock); | |
197 | if (work) { | |
198 | work->done_seq = seq; | |
199 | if (work->flushing) | |
200 | wake_up_all(&work->done); | |
201 | } | |
202 | ||
203 | if (kthread_should_stop()) { | |
204 | spin_unlock_irq(&dev->work_lock); | |
205 | __set_current_state(TASK_RUNNING); | |
64e1c807 | 206 | break; |
c23f3445 TH |
207 | } |
208 | if (!list_empty(&dev->work_list)) { | |
209 | work = list_first_entry(&dev->work_list, | |
210 | struct vhost_work, node); | |
211 | list_del_init(&work->node); | |
212 | seq = work->queue_seq; | |
213 | } else | |
214 | work = NULL; | |
215 | spin_unlock_irq(&dev->work_lock); | |
216 | ||
217 | if (work) { | |
218 | __set_current_state(TASK_RUNNING); | |
219 | work->fn(work); | |
220 | } else | |
221 | schedule(); | |
222 | ||
223 | } | |
64e1c807 MT |
224 | unuse_mm(dev->mm); |
225 | return 0; | |
c23f3445 TH |
226 | } |
227 | ||
e0e9b406 JW |
228 | /* Helper to allocate iovec buffers for all vqs. */ |
229 | static long vhost_dev_alloc_iovecs(struct vhost_dev *dev) | |
230 | { | |
231 | int i; | |
d47effe1 | 232 | |
e0e9b406 JW |
233 | for (i = 0; i < dev->nvqs; ++i) { |
234 | dev->vqs[i].indirect = kmalloc(sizeof *dev->vqs[i].indirect * | |
235 | UIO_MAXIOV, GFP_KERNEL); | |
236 | dev->vqs[i].log = kmalloc(sizeof *dev->vqs[i].log * UIO_MAXIOV, | |
237 | GFP_KERNEL); | |
238 | dev->vqs[i].heads = kmalloc(sizeof *dev->vqs[i].heads * | |
239 | UIO_MAXIOV, GFP_KERNEL); | |
240 | ||
241 | if (!dev->vqs[i].indirect || !dev->vqs[i].log || | |
242 | !dev->vqs[i].heads) | |
243 | goto err_nomem; | |
244 | } | |
245 | return 0; | |
d47effe1 | 246 | |
e0e9b406 JW |
247 | err_nomem: |
248 | for (; i >= 0; --i) { | |
249 | kfree(dev->vqs[i].indirect); | |
250 | kfree(dev->vqs[i].log); | |
251 | kfree(dev->vqs[i].heads); | |
252 | } | |
253 | return -ENOMEM; | |
254 | } | |
255 | ||
256 | static void vhost_dev_free_iovecs(struct vhost_dev *dev) | |
257 | { | |
258 | int i; | |
d47effe1 | 259 | |
e0e9b406 JW |
260 | for (i = 0; i < dev->nvqs; ++i) { |
261 | kfree(dev->vqs[i].indirect); | |
262 | dev->vqs[i].indirect = NULL; | |
263 | kfree(dev->vqs[i].log); | |
264 | dev->vqs[i].log = NULL; | |
265 | kfree(dev->vqs[i].heads); | |
266 | dev->vqs[i].heads = NULL; | |
267 | } | |
268 | } | |
269 | ||
3a4d5c94 MT |
270 | long vhost_dev_init(struct vhost_dev *dev, |
271 | struct vhost_virtqueue *vqs, int nvqs) | |
272 | { | |
273 | int i; | |
c23f3445 | 274 | |
3a4d5c94 MT |
275 | dev->vqs = vqs; |
276 | dev->nvqs = nvqs; | |
277 | mutex_init(&dev->mutex); | |
278 | dev->log_ctx = NULL; | |
279 | dev->log_file = NULL; | |
280 | dev->memory = NULL; | |
281 | dev->mm = NULL; | |
c23f3445 TH |
282 | spin_lock_init(&dev->work_lock); |
283 | INIT_LIST_HEAD(&dev->work_list); | |
284 | dev->worker = NULL; | |
3a4d5c94 MT |
285 | |
286 | for (i = 0; i < dev->nvqs; ++i) { | |
e0e9b406 JW |
287 | dev->vqs[i].log = NULL; |
288 | dev->vqs[i].indirect = NULL; | |
289 | dev->vqs[i].heads = NULL; | |
3a4d5c94 MT |
290 | dev->vqs[i].dev = dev; |
291 | mutex_init(&dev->vqs[i].mutex); | |
292 | vhost_vq_reset(dev, dev->vqs + i); | |
293 | if (dev->vqs[i].handle_kick) | |
294 | vhost_poll_init(&dev->vqs[i].poll, | |
c23f3445 | 295 | dev->vqs[i].handle_kick, POLLIN, dev); |
3a4d5c94 | 296 | } |
c23f3445 | 297 | |
3a4d5c94 MT |
298 | return 0; |
299 | } | |
300 | ||
301 | /* Caller should have device mutex */ | |
302 | long vhost_dev_check_owner(struct vhost_dev *dev) | |
303 | { | |
304 | /* Are you the owner? If not, I don't think you mean to do that */ | |
305 | return dev->mm == current->mm ? 0 : -EPERM; | |
306 | } | |
307 | ||
87d6a412 | 308 | struct vhost_attach_cgroups_struct { |
d47effe1 KK |
309 | struct vhost_work work; |
310 | struct task_struct *owner; | |
311 | int ret; | |
87d6a412 MT |
312 | }; |
313 | ||
314 | static void vhost_attach_cgroups_work(struct vhost_work *work) | |
315 | { | |
d47effe1 KK |
316 | struct vhost_attach_cgroups_struct *s; |
317 | ||
318 | s = container_of(work, struct vhost_attach_cgroups_struct, work); | |
319 | s->ret = cgroup_attach_task_all(s->owner, current); | |
87d6a412 MT |
320 | } |
321 | ||
322 | static int vhost_attach_cgroups(struct vhost_dev *dev) | |
323 | { | |
d47effe1 KK |
324 | struct vhost_attach_cgroups_struct attach; |
325 | ||
326 | attach.owner = current; | |
327 | vhost_work_init(&attach.work, vhost_attach_cgroups_work); | |
328 | vhost_work_queue(dev, &attach.work); | |
329 | vhost_work_flush(dev, &attach.work); | |
330 | return attach.ret; | |
87d6a412 MT |
331 | } |
332 | ||
3a4d5c94 MT |
333 | /* Caller should have device mutex */ |
334 | static long vhost_dev_set_owner(struct vhost_dev *dev) | |
335 | { | |
c23f3445 TH |
336 | struct task_struct *worker; |
337 | int err; | |
d47effe1 | 338 | |
3a4d5c94 | 339 | /* Is there an owner already? */ |
c23f3445 TH |
340 | if (dev->mm) { |
341 | err = -EBUSY; | |
342 | goto err_mm; | |
343 | } | |
d47effe1 | 344 | |
3a4d5c94 MT |
345 | /* No owner, become one */ |
346 | dev->mm = get_task_mm(current); | |
c23f3445 TH |
347 | worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid); |
348 | if (IS_ERR(worker)) { | |
349 | err = PTR_ERR(worker); | |
350 | goto err_worker; | |
351 | } | |
352 | ||
353 | dev->worker = worker; | |
87d6a412 MT |
354 | wake_up_process(worker); /* avoid contributing to loadavg */ |
355 | ||
356 | err = vhost_attach_cgroups(dev); | |
9e3d1957 MT |
357 | if (err) |
358 | goto err_cgroup; | |
c23f3445 | 359 | |
e0e9b406 JW |
360 | err = vhost_dev_alloc_iovecs(dev); |
361 | if (err) | |
362 | goto err_cgroup; | |
363 | ||
3a4d5c94 | 364 | return 0; |
9e3d1957 MT |
365 | err_cgroup: |
366 | kthread_stop(worker); | |
615cc221 | 367 | dev->worker = NULL; |
c23f3445 TH |
368 | err_worker: |
369 | if (dev->mm) | |
370 | mmput(dev->mm); | |
371 | dev->mm = NULL; | |
372 | err_mm: | |
373 | return err; | |
3a4d5c94 MT |
374 | } |
375 | ||
376 | /* Caller should have device mutex */ | |
377 | long vhost_dev_reset_owner(struct vhost_dev *dev) | |
378 | { | |
379 | struct vhost_memory *memory; | |
380 | ||
381 | /* Restore memory to default empty mapping. */ | |
382 | memory = kmalloc(offsetof(struct vhost_memory, regions), GFP_KERNEL); | |
383 | if (!memory) | |
384 | return -ENOMEM; | |
385 | ||
386 | vhost_dev_cleanup(dev); | |
387 | ||
388 | memory->nregions = 0; | |
28457ee6 | 389 | RCU_INIT_POINTER(dev->memory, memory); |
3a4d5c94 MT |
390 | return 0; |
391 | } | |
392 | ||
393 | /* Caller should have device mutex */ | |
394 | void vhost_dev_cleanup(struct vhost_dev *dev) | |
395 | { | |
396 | int i; | |
d47effe1 | 397 | |
3a4d5c94 MT |
398 | for (i = 0; i < dev->nvqs; ++i) { |
399 | if (dev->vqs[i].kick && dev->vqs[i].handle_kick) { | |
400 | vhost_poll_stop(&dev->vqs[i].poll); | |
401 | vhost_poll_flush(&dev->vqs[i].poll); | |
402 | } | |
403 | if (dev->vqs[i].error_ctx) | |
404 | eventfd_ctx_put(dev->vqs[i].error_ctx); | |
405 | if (dev->vqs[i].error) | |
406 | fput(dev->vqs[i].error); | |
407 | if (dev->vqs[i].kick) | |
408 | fput(dev->vqs[i].kick); | |
409 | if (dev->vqs[i].call_ctx) | |
410 | eventfd_ctx_put(dev->vqs[i].call_ctx); | |
411 | if (dev->vqs[i].call) | |
412 | fput(dev->vqs[i].call); | |
413 | vhost_vq_reset(dev, dev->vqs + i); | |
414 | } | |
e0e9b406 | 415 | vhost_dev_free_iovecs(dev); |
3a4d5c94 MT |
416 | if (dev->log_ctx) |
417 | eventfd_ctx_put(dev->log_ctx); | |
418 | dev->log_ctx = NULL; | |
419 | if (dev->log_file) | |
420 | fput(dev->log_file); | |
421 | dev->log_file = NULL; | |
422 | /* No one will access memory at this point */ | |
28457ee6 AB |
423 | kfree(rcu_dereference_protected(dev->memory, |
424 | lockdep_is_held(&dev->mutex))); | |
425 | RCU_INIT_POINTER(dev->memory, NULL); | |
c23f3445 | 426 | WARN_ON(!list_empty(&dev->work_list)); |
78b620ce ED |
427 | if (dev->worker) { |
428 | kthread_stop(dev->worker); | |
429 | dev->worker = NULL; | |
430 | } | |
533a19b4 MT |
431 | if (dev->mm) |
432 | mmput(dev->mm); | |
433 | dev->mm = NULL; | |
3a4d5c94 MT |
434 | } |
435 | ||
436 | static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz) | |
437 | { | |
438 | u64 a = addr / VHOST_PAGE_SIZE / 8; | |
d47effe1 | 439 | |
3a4d5c94 MT |
440 | /* Make sure 64 bit math will not overflow. */ |
441 | if (a > ULONG_MAX - (unsigned long)log_base || | |
442 | a + (unsigned long)log_base > ULONG_MAX) | |
6d97e55f | 443 | return 0; |
3a4d5c94 MT |
444 | |
445 | return access_ok(VERIFY_WRITE, log_base + a, | |
446 | (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8); | |
447 | } | |
448 | ||
449 | /* Caller should have vq mutex and device mutex. */ | |
450 | static int vq_memory_access_ok(void __user *log_base, struct vhost_memory *mem, | |
451 | int log_all) | |
452 | { | |
453 | int i; | |
179b284e | 454 | |
f8322fbe MT |
455 | if (!mem) |
456 | return 0; | |
179b284e | 457 | |
3a4d5c94 MT |
458 | for (i = 0; i < mem->nregions; ++i) { |
459 | struct vhost_memory_region *m = mem->regions + i; | |
460 | unsigned long a = m->userspace_addr; | |
461 | if (m->memory_size > ULONG_MAX) | |
462 | return 0; | |
463 | else if (!access_ok(VERIFY_WRITE, (void __user *)a, | |
464 | m->memory_size)) | |
465 | return 0; | |
466 | else if (log_all && !log_access_ok(log_base, | |
467 | m->guest_phys_addr, | |
468 | m->memory_size)) | |
469 | return 0; | |
470 | } | |
471 | return 1; | |
472 | } | |
473 | ||
474 | /* Can we switch to this memory table? */ | |
475 | /* Caller should have device mutex but not vq mutex */ | |
476 | static int memory_access_ok(struct vhost_dev *d, struct vhost_memory *mem, | |
477 | int log_all) | |
478 | { | |
479 | int i; | |
d47effe1 | 480 | |
3a4d5c94 MT |
481 | for (i = 0; i < d->nvqs; ++i) { |
482 | int ok; | |
483 | mutex_lock(&d->vqs[i].mutex); | |
484 | /* If ring is inactive, will check when it's enabled. */ | |
485 | if (d->vqs[i].private_data) | |
486 | ok = vq_memory_access_ok(d->vqs[i].log_base, mem, | |
487 | log_all); | |
488 | else | |
489 | ok = 1; | |
490 | mutex_unlock(&d->vqs[i].mutex); | |
491 | if (!ok) | |
492 | return 0; | |
493 | } | |
494 | return 1; | |
495 | } | |
496 | ||
8ea8cf89 | 497 | static int vq_access_ok(struct vhost_dev *d, unsigned int num, |
3a4d5c94 MT |
498 | struct vring_desc __user *desc, |
499 | struct vring_avail __user *avail, | |
500 | struct vring_used __user *used) | |
501 | { | |
8ea8cf89 | 502 | size_t s = vhost_has_feature(d, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; |
3a4d5c94 MT |
503 | return access_ok(VERIFY_READ, desc, num * sizeof *desc) && |
504 | access_ok(VERIFY_READ, avail, | |
8ea8cf89 | 505 | sizeof *avail + num * sizeof *avail->ring + s) && |
3a4d5c94 | 506 | access_ok(VERIFY_WRITE, used, |
8ea8cf89 | 507 | sizeof *used + num * sizeof *used->ring + s); |
3a4d5c94 MT |
508 | } |
509 | ||
510 | /* Can we log writes? */ | |
511 | /* Caller should have device mutex but not vq mutex */ | |
512 | int vhost_log_access_ok(struct vhost_dev *dev) | |
513 | { | |
28457ee6 AB |
514 | struct vhost_memory *mp; |
515 | ||
516 | mp = rcu_dereference_protected(dev->memory, | |
517 | lockdep_is_held(&dev->mutex)); | |
518 | return memory_access_ok(dev, mp, 1); | |
3a4d5c94 MT |
519 | } |
520 | ||
521 | /* Verify access for write logging. */ | |
522 | /* Caller should have vq mutex and device mutex */ | |
8ea8cf89 MT |
523 | static int vq_log_access_ok(struct vhost_dev *d, struct vhost_virtqueue *vq, |
524 | void __user *log_base) | |
3a4d5c94 | 525 | { |
28457ee6 | 526 | struct vhost_memory *mp; |
8ea8cf89 | 527 | size_t s = vhost_has_feature(d, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; |
28457ee6 AB |
528 | |
529 | mp = rcu_dereference_protected(vq->dev->memory, | |
530 | lockdep_is_held(&vq->mutex)); | |
531 | return vq_memory_access_ok(log_base, mp, | |
3a4d5c94 MT |
532 | vhost_has_feature(vq->dev, VHOST_F_LOG_ALL)) && |
533 | (!vq->log_used || log_access_ok(log_base, vq->log_addr, | |
534 | sizeof *vq->used + | |
8ea8cf89 | 535 | vq->num * sizeof *vq->used->ring + s)); |
3a4d5c94 MT |
536 | } |
537 | ||
538 | /* Can we start vq? */ | |
539 | /* Caller should have vq mutex and device mutex */ | |
540 | int vhost_vq_access_ok(struct vhost_virtqueue *vq) | |
541 | { | |
8ea8cf89 MT |
542 | return vq_access_ok(vq->dev, vq->num, vq->desc, vq->avail, vq->used) && |
543 | vq_log_access_ok(vq->dev, vq, vq->log_base); | |
3a4d5c94 MT |
544 | } |
545 | ||
546 | static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) | |
547 | { | |
548 | struct vhost_memory mem, *newmem, *oldmem; | |
549 | unsigned long size = offsetof(struct vhost_memory, regions); | |
d47effe1 | 550 | |
7ad9c9d2 TY |
551 | if (copy_from_user(&mem, m, size)) |
552 | return -EFAULT; | |
3a4d5c94 MT |
553 | if (mem.padding) |
554 | return -EOPNOTSUPP; | |
555 | if (mem.nregions > VHOST_MEMORY_MAX_NREGIONS) | |
556 | return -E2BIG; | |
557 | newmem = kmalloc(size + mem.nregions * sizeof *m->regions, GFP_KERNEL); | |
558 | if (!newmem) | |
559 | return -ENOMEM; | |
560 | ||
561 | memcpy(newmem, &mem, size); | |
7ad9c9d2 TY |
562 | if (copy_from_user(newmem->regions, m->regions, |
563 | mem.nregions * sizeof *m->regions)) { | |
3a4d5c94 | 564 | kfree(newmem); |
7ad9c9d2 | 565 | return -EFAULT; |
3a4d5c94 MT |
566 | } |
567 | ||
d47effe1 KK |
568 | if (!memory_access_ok(d, newmem, |
569 | vhost_has_feature(d, VHOST_F_LOG_ALL))) { | |
a02c3789 | 570 | kfree(newmem); |
3a4d5c94 | 571 | return -EFAULT; |
a02c3789 | 572 | } |
28457ee6 AB |
573 | oldmem = rcu_dereference_protected(d->memory, |
574 | lockdep_is_held(&d->mutex)); | |
3a4d5c94 MT |
575 | rcu_assign_pointer(d->memory, newmem); |
576 | synchronize_rcu(); | |
577 | kfree(oldmem); | |
578 | return 0; | |
579 | } | |
580 | ||
581 | static int init_used(struct vhost_virtqueue *vq, | |
582 | struct vring_used __user *used) | |
583 | { | |
584 | int r = put_user(vq->used_flags, &used->flags); | |
d47effe1 | 585 | |
3a4d5c94 MT |
586 | if (r) |
587 | return r; | |
8ea8cf89 | 588 | vq->signalled_used_valid = false; |
3a4d5c94 MT |
589 | return get_user(vq->last_used_idx, &used->idx); |
590 | } | |
591 | ||
592 | static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp) | |
593 | { | |
594 | struct file *eventfp, *filep = NULL, | |
595 | *pollstart = NULL, *pollstop = NULL; | |
596 | struct eventfd_ctx *ctx = NULL; | |
597 | u32 __user *idxp = argp; | |
598 | struct vhost_virtqueue *vq; | |
599 | struct vhost_vring_state s; | |
600 | struct vhost_vring_file f; | |
601 | struct vhost_vring_addr a; | |
602 | u32 idx; | |
603 | long r; | |
604 | ||
605 | r = get_user(idx, idxp); | |
606 | if (r < 0) | |
607 | return r; | |
0f3d9a17 | 608 | if (idx >= d->nvqs) |
3a4d5c94 MT |
609 | return -ENOBUFS; |
610 | ||
611 | vq = d->vqs + idx; | |
612 | ||
613 | mutex_lock(&vq->mutex); | |
614 | ||
615 | switch (ioctl) { | |
616 | case VHOST_SET_VRING_NUM: | |
617 | /* Resizing ring with an active backend? | |
618 | * You don't want to do that. */ | |
619 | if (vq->private_data) { | |
620 | r = -EBUSY; | |
621 | break; | |
622 | } | |
7ad9c9d2 TY |
623 | if (copy_from_user(&s, argp, sizeof s)) { |
624 | r = -EFAULT; | |
3a4d5c94 | 625 | break; |
7ad9c9d2 | 626 | } |
3a4d5c94 MT |
627 | if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) { |
628 | r = -EINVAL; | |
629 | break; | |
630 | } | |
631 | vq->num = s.num; | |
632 | break; | |
633 | case VHOST_SET_VRING_BASE: | |
634 | /* Moving base with an active backend? | |
635 | * You don't want to do that. */ | |
636 | if (vq->private_data) { | |
637 | r = -EBUSY; | |
638 | break; | |
639 | } | |
7ad9c9d2 TY |
640 | if (copy_from_user(&s, argp, sizeof s)) { |
641 | r = -EFAULT; | |
3a4d5c94 | 642 | break; |
7ad9c9d2 | 643 | } |
3a4d5c94 MT |
644 | if (s.num > 0xffff) { |
645 | r = -EINVAL; | |
646 | break; | |
647 | } | |
648 | vq->last_avail_idx = s.num; | |
649 | /* Forget the cached index value. */ | |
650 | vq->avail_idx = vq->last_avail_idx; | |
651 | break; | |
652 | case VHOST_GET_VRING_BASE: | |
653 | s.index = idx; | |
654 | s.num = vq->last_avail_idx; | |
7ad9c9d2 TY |
655 | if (copy_to_user(argp, &s, sizeof s)) |
656 | r = -EFAULT; | |
3a4d5c94 MT |
657 | break; |
658 | case VHOST_SET_VRING_ADDR: | |
7ad9c9d2 TY |
659 | if (copy_from_user(&a, argp, sizeof a)) { |
660 | r = -EFAULT; | |
3a4d5c94 | 661 | break; |
7ad9c9d2 | 662 | } |
3a4d5c94 MT |
663 | if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) { |
664 | r = -EOPNOTSUPP; | |
665 | break; | |
666 | } | |
667 | /* For 32bit, verify that the top 32bits of the user | |
668 | data are set to zero. */ | |
669 | if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr || | |
670 | (u64)(unsigned long)a.used_user_addr != a.used_user_addr || | |
671 | (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) { | |
672 | r = -EFAULT; | |
673 | break; | |
674 | } | |
675 | if ((a.avail_user_addr & (sizeof *vq->avail->ring - 1)) || | |
676 | (a.used_user_addr & (sizeof *vq->used->ring - 1)) || | |
677 | (a.log_guest_addr & (sizeof *vq->used->ring - 1))) { | |
678 | r = -EINVAL; | |
679 | break; | |
680 | } | |
681 | ||
682 | /* We only verify access here if backend is configured. | |
683 | * If it is not, we don't as size might not have been setup. | |
684 | * We will verify when backend is configured. */ | |
685 | if (vq->private_data) { | |
8ea8cf89 | 686 | if (!vq_access_ok(d, vq->num, |
3a4d5c94 MT |
687 | (void __user *)(unsigned long)a.desc_user_addr, |
688 | (void __user *)(unsigned long)a.avail_user_addr, | |
689 | (void __user *)(unsigned long)a.used_user_addr)) { | |
690 | r = -EINVAL; | |
691 | break; | |
692 | } | |
693 | ||
694 | /* Also validate log access for used ring if enabled. */ | |
695 | if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) && | |
696 | !log_access_ok(vq->log_base, a.log_guest_addr, | |
697 | sizeof *vq->used + | |
698 | vq->num * sizeof *vq->used->ring)) { | |
699 | r = -EINVAL; | |
700 | break; | |
701 | } | |
702 | } | |
703 | ||
704 | r = init_used(vq, (struct vring_used __user *)(unsigned long) | |
705 | a.used_user_addr); | |
706 | if (r) | |
707 | break; | |
708 | vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG)); | |
709 | vq->desc = (void __user *)(unsigned long)a.desc_user_addr; | |
710 | vq->avail = (void __user *)(unsigned long)a.avail_user_addr; | |
711 | vq->log_addr = a.log_guest_addr; | |
712 | vq->used = (void __user *)(unsigned long)a.used_user_addr; | |
713 | break; | |
714 | case VHOST_SET_VRING_KICK: | |
7ad9c9d2 TY |
715 | if (copy_from_user(&f, argp, sizeof f)) { |
716 | r = -EFAULT; | |
3a4d5c94 | 717 | break; |
7ad9c9d2 | 718 | } |
3a4d5c94 | 719 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
720 | if (IS_ERR(eventfp)) { |
721 | r = PTR_ERR(eventfp); | |
722 | break; | |
723 | } | |
3a4d5c94 MT |
724 | if (eventfp != vq->kick) { |
725 | pollstop = filep = vq->kick; | |
726 | pollstart = vq->kick = eventfp; | |
727 | } else | |
728 | filep = eventfp; | |
729 | break; | |
730 | case VHOST_SET_VRING_CALL: | |
7ad9c9d2 TY |
731 | if (copy_from_user(&f, argp, sizeof f)) { |
732 | r = -EFAULT; | |
3a4d5c94 | 733 | break; |
7ad9c9d2 | 734 | } |
3a4d5c94 | 735 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
736 | if (IS_ERR(eventfp)) { |
737 | r = PTR_ERR(eventfp); | |
738 | break; | |
739 | } | |
3a4d5c94 MT |
740 | if (eventfp != vq->call) { |
741 | filep = vq->call; | |
742 | ctx = vq->call_ctx; | |
743 | vq->call = eventfp; | |
744 | vq->call_ctx = eventfp ? | |
745 | eventfd_ctx_fileget(eventfp) : NULL; | |
746 | } else | |
747 | filep = eventfp; | |
748 | break; | |
749 | case VHOST_SET_VRING_ERR: | |
7ad9c9d2 TY |
750 | if (copy_from_user(&f, argp, sizeof f)) { |
751 | r = -EFAULT; | |
3a4d5c94 | 752 | break; |
7ad9c9d2 | 753 | } |
3a4d5c94 | 754 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
755 | if (IS_ERR(eventfp)) { |
756 | r = PTR_ERR(eventfp); | |
757 | break; | |
758 | } | |
3a4d5c94 MT |
759 | if (eventfp != vq->error) { |
760 | filep = vq->error; | |
761 | vq->error = eventfp; | |
762 | ctx = vq->error_ctx; | |
763 | vq->error_ctx = eventfp ? | |
764 | eventfd_ctx_fileget(eventfp) : NULL; | |
765 | } else | |
766 | filep = eventfp; | |
767 | break; | |
768 | default: | |
769 | r = -ENOIOCTLCMD; | |
770 | } | |
771 | ||
772 | if (pollstop && vq->handle_kick) | |
773 | vhost_poll_stop(&vq->poll); | |
774 | ||
775 | if (ctx) | |
776 | eventfd_ctx_put(ctx); | |
777 | if (filep) | |
778 | fput(filep); | |
779 | ||
780 | if (pollstart && vq->handle_kick) | |
781 | vhost_poll_start(&vq->poll, vq->kick); | |
782 | ||
783 | mutex_unlock(&vq->mutex); | |
784 | ||
785 | if (pollstop && vq->handle_kick) | |
786 | vhost_poll_flush(&vq->poll); | |
787 | return r; | |
788 | } | |
789 | ||
790 | /* Caller must have device mutex */ | |
791 | long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, unsigned long arg) | |
792 | { | |
793 | void __user *argp = (void __user *)arg; | |
794 | struct file *eventfp, *filep = NULL; | |
795 | struct eventfd_ctx *ctx = NULL; | |
796 | u64 p; | |
797 | long r; | |
798 | int i, fd; | |
799 | ||
800 | /* If you are not the owner, you can become one */ | |
801 | if (ioctl == VHOST_SET_OWNER) { | |
802 | r = vhost_dev_set_owner(d); | |
803 | goto done; | |
804 | } | |
805 | ||
806 | /* You must be the owner to do anything else */ | |
807 | r = vhost_dev_check_owner(d); | |
808 | if (r) | |
809 | goto done; | |
810 | ||
811 | switch (ioctl) { | |
812 | case VHOST_SET_MEM_TABLE: | |
813 | r = vhost_set_memory(d, argp); | |
814 | break; | |
815 | case VHOST_SET_LOG_BASE: | |
7ad9c9d2 TY |
816 | if (copy_from_user(&p, argp, sizeof p)) { |
817 | r = -EFAULT; | |
3a4d5c94 | 818 | break; |
7ad9c9d2 | 819 | } |
3a4d5c94 MT |
820 | if ((u64)(unsigned long)p != p) { |
821 | r = -EFAULT; | |
822 | break; | |
823 | } | |
824 | for (i = 0; i < d->nvqs; ++i) { | |
825 | struct vhost_virtqueue *vq; | |
826 | void __user *base = (void __user *)(unsigned long)p; | |
827 | vq = d->vqs + i; | |
828 | mutex_lock(&vq->mutex); | |
829 | /* If ring is inactive, will check when it's enabled. */ | |
8ea8cf89 | 830 | if (vq->private_data && !vq_log_access_ok(d, vq, base)) |
3a4d5c94 MT |
831 | r = -EFAULT; |
832 | else | |
833 | vq->log_base = base; | |
834 | mutex_unlock(&vq->mutex); | |
835 | } | |
836 | break; | |
837 | case VHOST_SET_LOG_FD: | |
838 | r = get_user(fd, (int __user *)argp); | |
839 | if (r < 0) | |
840 | break; | |
841 | eventfp = fd == -1 ? NULL : eventfd_fget(fd); | |
842 | if (IS_ERR(eventfp)) { | |
843 | r = PTR_ERR(eventfp); | |
844 | break; | |
845 | } | |
846 | if (eventfp != d->log_file) { | |
847 | filep = d->log_file; | |
848 | ctx = d->log_ctx; | |
849 | d->log_ctx = eventfp ? | |
850 | eventfd_ctx_fileget(eventfp) : NULL; | |
851 | } else | |
852 | filep = eventfp; | |
853 | for (i = 0; i < d->nvqs; ++i) { | |
854 | mutex_lock(&d->vqs[i].mutex); | |
855 | d->vqs[i].log_ctx = d->log_ctx; | |
856 | mutex_unlock(&d->vqs[i].mutex); | |
857 | } | |
858 | if (ctx) | |
859 | eventfd_ctx_put(ctx); | |
860 | if (filep) | |
861 | fput(filep); | |
862 | break; | |
863 | default: | |
864 | r = vhost_set_vring(d, ioctl, argp); | |
865 | break; | |
866 | } | |
867 | done: | |
868 | return r; | |
869 | } | |
870 | ||
871 | static const struct vhost_memory_region *find_region(struct vhost_memory *mem, | |
872 | __u64 addr, __u32 len) | |
873 | { | |
874 | struct vhost_memory_region *reg; | |
875 | int i; | |
d47effe1 | 876 | |
3a4d5c94 MT |
877 | /* linear search is not brilliant, but we really have on the order of 6 |
878 | * regions in practice */ | |
879 | for (i = 0; i < mem->nregions; ++i) { | |
880 | reg = mem->regions + i; | |
881 | if (reg->guest_phys_addr <= addr && | |
882 | reg->guest_phys_addr + reg->memory_size - 1 >= addr) | |
883 | return reg; | |
884 | } | |
885 | return NULL; | |
886 | } | |
887 | ||
888 | /* TODO: This is really inefficient. We need something like get_user() | |
889 | * (instruction directly accesses the data, with an exception table entry | |
890 | * returning -EFAULT). See Documentation/x86/exception-tables.txt. | |
891 | */ | |
892 | static int set_bit_to_user(int nr, void __user *addr) | |
893 | { | |
894 | unsigned long log = (unsigned long)addr; | |
895 | struct page *page; | |
896 | void *base; | |
897 | int bit = nr + (log % PAGE_SIZE) * 8; | |
898 | int r; | |
d47effe1 | 899 | |
3a4d5c94 | 900 | r = get_user_pages_fast(log, 1, 1, &page); |
d6db3f5c | 901 | if (r < 0) |
3a4d5c94 | 902 | return r; |
d6db3f5c | 903 | BUG_ON(r != 1); |
3a4d5c94 MT |
904 | base = kmap_atomic(page, KM_USER0); |
905 | set_bit(bit, base); | |
906 | kunmap_atomic(base, KM_USER0); | |
907 | set_page_dirty_lock(page); | |
908 | put_page(page); | |
909 | return 0; | |
910 | } | |
911 | ||
912 | static int log_write(void __user *log_base, | |
913 | u64 write_address, u64 write_length) | |
914 | { | |
28831ee6 | 915 | u64 write_page = write_address / VHOST_PAGE_SIZE; |
3a4d5c94 | 916 | int r; |
d47effe1 | 917 | |
3a4d5c94 MT |
918 | if (!write_length) |
919 | return 0; | |
3bf9be40 | 920 | write_length += write_address % VHOST_PAGE_SIZE; |
3a4d5c94 MT |
921 | for (;;) { |
922 | u64 base = (u64)(unsigned long)log_base; | |
28831ee6 MT |
923 | u64 log = base + write_page / 8; |
924 | int bit = write_page % 8; | |
3a4d5c94 MT |
925 | if ((u64)(unsigned long)log != log) |
926 | return -EFAULT; | |
927 | r = set_bit_to_user(bit, (void __user *)(unsigned long)log); | |
928 | if (r < 0) | |
929 | return r; | |
930 | if (write_length <= VHOST_PAGE_SIZE) | |
931 | break; | |
932 | write_length -= VHOST_PAGE_SIZE; | |
28831ee6 | 933 | write_page += 1; |
3a4d5c94 MT |
934 | } |
935 | return r; | |
936 | } | |
937 | ||
938 | int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, | |
939 | unsigned int log_num, u64 len) | |
940 | { | |
941 | int i, r; | |
942 | ||
943 | /* Make sure data written is seen before log. */ | |
5659338c | 944 | smp_wmb(); |
3a4d5c94 MT |
945 | for (i = 0; i < log_num; ++i) { |
946 | u64 l = min(log[i].len, len); | |
947 | r = log_write(vq->log_base, log[i].addr, l); | |
948 | if (r < 0) | |
949 | return r; | |
950 | len -= l; | |
5786aee8 MT |
951 | if (!len) { |
952 | if (vq->log_ctx) | |
953 | eventfd_signal(vq->log_ctx, 1); | |
3a4d5c94 | 954 | return 0; |
5786aee8 | 955 | } |
3a4d5c94 | 956 | } |
3a4d5c94 MT |
957 | /* Length written exceeds what we have stored. This is a bug. */ |
958 | BUG(); | |
959 | return 0; | |
960 | } | |
961 | ||
a8d3782f CH |
962 | static int translate_desc(struct vhost_dev *dev, u64 addr, u32 len, |
963 | struct iovec iov[], int iov_size) | |
3a4d5c94 MT |
964 | { |
965 | const struct vhost_memory_region *reg; | |
966 | struct vhost_memory *mem; | |
967 | struct iovec *_iov; | |
968 | u64 s = 0; | |
969 | int ret = 0; | |
970 | ||
971 | rcu_read_lock(); | |
972 | ||
973 | mem = rcu_dereference(dev->memory); | |
974 | while ((u64)len > s) { | |
975 | u64 size; | |
7b3384fc | 976 | if (unlikely(ret >= iov_size)) { |
3a4d5c94 MT |
977 | ret = -ENOBUFS; |
978 | break; | |
979 | } | |
980 | reg = find_region(mem, addr, len); | |
7b3384fc | 981 | if (unlikely(!reg)) { |
3a4d5c94 MT |
982 | ret = -EFAULT; |
983 | break; | |
984 | } | |
985 | _iov = iov + ret; | |
986 | size = reg->memory_size - addr + reg->guest_phys_addr; | |
987 | _iov->iov_len = min((u64)len, size); | |
a8d3782f | 988 | _iov->iov_base = (void __user *)(unsigned long) |
3a4d5c94 MT |
989 | (reg->userspace_addr + addr - reg->guest_phys_addr); |
990 | s += size; | |
991 | addr += size; | |
992 | ++ret; | |
993 | } | |
994 | ||
995 | rcu_read_unlock(); | |
996 | return ret; | |
997 | } | |
998 | ||
999 | /* Each buffer in the virtqueues is actually a chain of descriptors. This | |
1000 | * function returns the next descriptor in the chain, | |
1001 | * or -1U if we're at the end. */ | |
1002 | static unsigned next_desc(struct vring_desc *desc) | |
1003 | { | |
1004 | unsigned int next; | |
1005 | ||
1006 | /* If this descriptor says it doesn't chain, we're done. */ | |
1007 | if (!(desc->flags & VRING_DESC_F_NEXT)) | |
1008 | return -1U; | |
1009 | ||
1010 | /* Check they're not leading us off end of descriptors. */ | |
1011 | next = desc->next; | |
1012 | /* Make sure compiler knows to grab that: we don't want it changing! */ | |
1013 | /* We will use the result as an index in an array, so most | |
1014 | * architectures only need a compiler barrier here. */ | |
1015 | read_barrier_depends(); | |
1016 | ||
1017 | return next; | |
1018 | } | |
1019 | ||
7b3384fc MT |
1020 | static int get_indirect(struct vhost_dev *dev, struct vhost_virtqueue *vq, |
1021 | struct iovec iov[], unsigned int iov_size, | |
1022 | unsigned int *out_num, unsigned int *in_num, | |
1023 | struct vhost_log *log, unsigned int *log_num, | |
1024 | struct vring_desc *indirect) | |
3a4d5c94 MT |
1025 | { |
1026 | struct vring_desc desc; | |
1027 | unsigned int i = 0, count, found = 0; | |
1028 | int ret; | |
1029 | ||
1030 | /* Sanity check */ | |
7b3384fc | 1031 | if (unlikely(indirect->len % sizeof desc)) { |
3a4d5c94 MT |
1032 | vq_err(vq, "Invalid length in indirect descriptor: " |
1033 | "len 0x%llx not multiple of 0x%zx\n", | |
1034 | (unsigned long long)indirect->len, | |
1035 | sizeof desc); | |
1036 | return -EINVAL; | |
1037 | } | |
1038 | ||
1039 | ret = translate_desc(dev, indirect->addr, indirect->len, vq->indirect, | |
e0e9b406 | 1040 | UIO_MAXIOV); |
7b3384fc | 1041 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1042 | vq_err(vq, "Translation failure %d in indirect.\n", ret); |
1043 | return ret; | |
1044 | } | |
1045 | ||
1046 | /* We will use the result as an address to read from, so most | |
1047 | * architectures only need a compiler barrier here. */ | |
1048 | read_barrier_depends(); | |
1049 | ||
1050 | count = indirect->len / sizeof desc; | |
1051 | /* Buffers are chained via a 16 bit next field, so | |
1052 | * we can have at most 2^16 of these. */ | |
7b3384fc | 1053 | if (unlikely(count > USHRT_MAX + 1)) { |
3a4d5c94 MT |
1054 | vq_err(vq, "Indirect buffer length too big: %d\n", |
1055 | indirect->len); | |
1056 | return -E2BIG; | |
1057 | } | |
1058 | ||
1059 | do { | |
1060 | unsigned iov_count = *in_num + *out_num; | |
7b3384fc | 1061 | if (unlikely(++found > count)) { |
3a4d5c94 MT |
1062 | vq_err(vq, "Loop detected: last one at %u " |
1063 | "indirect size %u\n", | |
1064 | i, count); | |
1065 | return -EINVAL; | |
1066 | } | |
d47effe1 KK |
1067 | if (unlikely(memcpy_fromiovec((unsigned char *)&desc, |
1068 | vq->indirect, sizeof desc))) { | |
3a4d5c94 MT |
1069 | vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n", |
1070 | i, (size_t)indirect->addr + i * sizeof desc); | |
1071 | return -EINVAL; | |
1072 | } | |
7b3384fc | 1073 | if (unlikely(desc.flags & VRING_DESC_F_INDIRECT)) { |
3a4d5c94 MT |
1074 | vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n", |
1075 | i, (size_t)indirect->addr + i * sizeof desc); | |
1076 | return -EINVAL; | |
1077 | } | |
1078 | ||
1079 | ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, | |
1080 | iov_size - iov_count); | |
7b3384fc | 1081 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1082 | vq_err(vq, "Translation failure %d indirect idx %d\n", |
1083 | ret, i); | |
1084 | return ret; | |
1085 | } | |
1086 | /* If this is an input descriptor, increment that count. */ | |
1087 | if (desc.flags & VRING_DESC_F_WRITE) { | |
1088 | *in_num += ret; | |
1089 | if (unlikely(log)) { | |
1090 | log[*log_num].addr = desc.addr; | |
1091 | log[*log_num].len = desc.len; | |
1092 | ++*log_num; | |
1093 | } | |
1094 | } else { | |
1095 | /* If it's an output descriptor, they're all supposed | |
1096 | * to come before any input descriptors. */ | |
7b3384fc | 1097 | if (unlikely(*in_num)) { |
3a4d5c94 MT |
1098 | vq_err(vq, "Indirect descriptor " |
1099 | "has out after in: idx %d\n", i); | |
1100 | return -EINVAL; | |
1101 | } | |
1102 | *out_num += ret; | |
1103 | } | |
1104 | } while ((i = next_desc(&desc)) != -1); | |
1105 | return 0; | |
1106 | } | |
1107 | ||
1108 | /* This looks in the virtqueue and for the first available buffer, and converts | |
1109 | * it to an iovec for convenient access. Since descriptors consist of some | |
1110 | * number of output then some number of input descriptors, it's actually two | |
1111 | * iovecs, but we pack them into one and note how many of each there were. | |
1112 | * | |
d5675bd2 MT |
1113 | * This function returns the descriptor number found, or vq->num (which is |
1114 | * never a valid descriptor number) if none was found. A negative code is | |
1115 | * returned on error. */ | |
1116 | int vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq, | |
1117 | struct iovec iov[], unsigned int iov_size, | |
1118 | unsigned int *out_num, unsigned int *in_num, | |
1119 | struct vhost_log *log, unsigned int *log_num) | |
3a4d5c94 MT |
1120 | { |
1121 | struct vring_desc desc; | |
1122 | unsigned int i, head, found = 0; | |
1123 | u16 last_avail_idx; | |
1124 | int ret; | |
1125 | ||
1126 | /* Check it isn't doing very strange things with descriptor numbers. */ | |
1127 | last_avail_idx = vq->last_avail_idx; | |
8b7347aa | 1128 | if (unlikely(__get_user(vq->avail_idx, &vq->avail->idx))) { |
3a4d5c94 MT |
1129 | vq_err(vq, "Failed to access avail idx at %p\n", |
1130 | &vq->avail->idx); | |
d5675bd2 | 1131 | return -EFAULT; |
3a4d5c94 MT |
1132 | } |
1133 | ||
7b3384fc | 1134 | if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) { |
3a4d5c94 MT |
1135 | vq_err(vq, "Guest moved used index from %u to %u", |
1136 | last_avail_idx, vq->avail_idx); | |
d5675bd2 | 1137 | return -EFAULT; |
3a4d5c94 MT |
1138 | } |
1139 | ||
1140 | /* If there's nothing new since last we looked, return invalid. */ | |
1141 | if (vq->avail_idx == last_avail_idx) | |
1142 | return vq->num; | |
1143 | ||
1144 | /* Only get avail ring entries after they have been exposed by guest. */ | |
5659338c | 1145 | smp_rmb(); |
3a4d5c94 MT |
1146 | |
1147 | /* Grab the next descriptor number they're advertising, and increment | |
1148 | * the index we've seen. */ | |
8b7347aa MT |
1149 | if (unlikely(__get_user(head, |
1150 | &vq->avail->ring[last_avail_idx % vq->num]))) { | |
3a4d5c94 MT |
1151 | vq_err(vq, "Failed to read head: idx %d address %p\n", |
1152 | last_avail_idx, | |
1153 | &vq->avail->ring[last_avail_idx % vq->num]); | |
d5675bd2 | 1154 | return -EFAULT; |
3a4d5c94 MT |
1155 | } |
1156 | ||
1157 | /* If their number is silly, that's an error. */ | |
7b3384fc | 1158 | if (unlikely(head >= vq->num)) { |
3a4d5c94 MT |
1159 | vq_err(vq, "Guest says index %u > %u is available", |
1160 | head, vq->num); | |
d5675bd2 | 1161 | return -EINVAL; |
3a4d5c94 MT |
1162 | } |
1163 | ||
1164 | /* When we start there are none of either input nor output. */ | |
1165 | *out_num = *in_num = 0; | |
1166 | if (unlikely(log)) | |
1167 | *log_num = 0; | |
1168 | ||
1169 | i = head; | |
1170 | do { | |
1171 | unsigned iov_count = *in_num + *out_num; | |
7b3384fc | 1172 | if (unlikely(i >= vq->num)) { |
3a4d5c94 MT |
1173 | vq_err(vq, "Desc index is %u > %u, head = %u", |
1174 | i, vq->num, head); | |
d5675bd2 | 1175 | return -EINVAL; |
3a4d5c94 | 1176 | } |
7b3384fc | 1177 | if (unlikely(++found > vq->num)) { |
3a4d5c94 MT |
1178 | vq_err(vq, "Loop detected: last one at %u " |
1179 | "vq size %u head %u\n", | |
1180 | i, vq->num, head); | |
d5675bd2 | 1181 | return -EINVAL; |
3a4d5c94 | 1182 | } |
fcc042a2 | 1183 | ret = __copy_from_user(&desc, vq->desc + i, sizeof desc); |
7b3384fc | 1184 | if (unlikely(ret)) { |
3a4d5c94 MT |
1185 | vq_err(vq, "Failed to get descriptor: idx %d addr %p\n", |
1186 | i, vq->desc + i); | |
d5675bd2 | 1187 | return -EFAULT; |
3a4d5c94 MT |
1188 | } |
1189 | if (desc.flags & VRING_DESC_F_INDIRECT) { | |
1190 | ret = get_indirect(dev, vq, iov, iov_size, | |
1191 | out_num, in_num, | |
1192 | log, log_num, &desc); | |
7b3384fc | 1193 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1194 | vq_err(vq, "Failure detected " |
1195 | "in indirect descriptor at idx %d\n", i); | |
d5675bd2 | 1196 | return ret; |
3a4d5c94 MT |
1197 | } |
1198 | continue; | |
1199 | } | |
1200 | ||
1201 | ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, | |
1202 | iov_size - iov_count); | |
7b3384fc | 1203 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1204 | vq_err(vq, "Translation failure %d descriptor idx %d\n", |
1205 | ret, i); | |
d5675bd2 | 1206 | return ret; |
3a4d5c94 MT |
1207 | } |
1208 | if (desc.flags & VRING_DESC_F_WRITE) { | |
1209 | /* If this is an input descriptor, | |
1210 | * increment that count. */ | |
1211 | *in_num += ret; | |
1212 | if (unlikely(log)) { | |
1213 | log[*log_num].addr = desc.addr; | |
1214 | log[*log_num].len = desc.len; | |
1215 | ++*log_num; | |
1216 | } | |
1217 | } else { | |
1218 | /* If it's an output descriptor, they're all supposed | |
1219 | * to come before any input descriptors. */ | |
7b3384fc | 1220 | if (unlikely(*in_num)) { |
3a4d5c94 MT |
1221 | vq_err(vq, "Descriptor has out after in: " |
1222 | "idx %d\n", i); | |
d5675bd2 | 1223 | return -EINVAL; |
3a4d5c94 MT |
1224 | } |
1225 | *out_num += ret; | |
1226 | } | |
1227 | } while ((i = next_desc(&desc)) != -1); | |
1228 | ||
1229 | /* On success, increment avail index. */ | |
1230 | vq->last_avail_idx++; | |
8ea8cf89 MT |
1231 | |
1232 | /* Assume notifications from guest are disabled at this point, | |
1233 | * if they aren't we would need to update avail_event index. */ | |
1234 | BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY)); | |
3a4d5c94 MT |
1235 | return head; |
1236 | } | |
1237 | ||
1238 | /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */ | |
8dd014ad | 1239 | void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n) |
3a4d5c94 | 1240 | { |
8dd014ad | 1241 | vq->last_avail_idx -= n; |
3a4d5c94 MT |
1242 | } |
1243 | ||
1244 | /* After we've used one of their buffers, we tell them about it. We'll then | |
1245 | * want to notify the guest, using eventfd. */ | |
1246 | int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len) | |
1247 | { | |
a8d3782f | 1248 | struct vring_used_elem __user *used; |
3a4d5c94 MT |
1249 | |
1250 | /* The virtqueue contains a ring of used buffers. Get a pointer to the | |
1251 | * next entry in that used ring. */ | |
1252 | used = &vq->used->ring[vq->last_used_idx % vq->num]; | |
8b7347aa | 1253 | if (__put_user(head, &used->id)) { |
3a4d5c94 MT |
1254 | vq_err(vq, "Failed to write used id"); |
1255 | return -EFAULT; | |
1256 | } | |
8b7347aa | 1257 | if (__put_user(len, &used->len)) { |
3a4d5c94 MT |
1258 | vq_err(vq, "Failed to write used len"); |
1259 | return -EFAULT; | |
1260 | } | |
1261 | /* Make sure buffer is written before we update index. */ | |
5659338c | 1262 | smp_wmb(); |
8b7347aa | 1263 | if (__put_user(vq->last_used_idx + 1, &vq->used->idx)) { |
3a4d5c94 MT |
1264 | vq_err(vq, "Failed to increment used idx"); |
1265 | return -EFAULT; | |
1266 | } | |
1267 | if (unlikely(vq->log_used)) { | |
1268 | /* Make sure data is seen before log. */ | |
5659338c | 1269 | smp_wmb(); |
86e9424d MT |
1270 | /* Log used ring entry write. */ |
1271 | log_write(vq->log_base, | |
a8d3782f CH |
1272 | vq->log_addr + |
1273 | ((void __user *)used - (void __user *)vq->used), | |
86e9424d MT |
1274 | sizeof *used); |
1275 | /* Log used index update. */ | |
1276 | log_write(vq->log_base, | |
1277 | vq->log_addr + offsetof(struct vring_used, idx), | |
1278 | sizeof vq->used->idx); | |
3a4d5c94 MT |
1279 | if (vq->log_ctx) |
1280 | eventfd_signal(vq->log_ctx, 1); | |
1281 | } | |
1282 | vq->last_used_idx++; | |
8ea8cf89 MT |
1283 | /* If the driver never bothers to signal in a very long while, |
1284 | * used index might wrap around. If that happens, invalidate | |
1285 | * signalled_used index we stored. TODO: make sure driver | |
1286 | * signals at least once in 2^16 and remove this. */ | |
1287 | if (unlikely(vq->last_used_idx == vq->signalled_used)) | |
1288 | vq->signalled_used_valid = false; | |
3a4d5c94 MT |
1289 | return 0; |
1290 | } | |
1291 | ||
8dd014ad DS |
1292 | static int __vhost_add_used_n(struct vhost_virtqueue *vq, |
1293 | struct vring_used_elem *heads, | |
1294 | unsigned count) | |
1295 | { | |
1296 | struct vring_used_elem __user *used; | |
8ea8cf89 | 1297 | u16 old, new; |
8dd014ad DS |
1298 | int start; |
1299 | ||
1300 | start = vq->last_used_idx % vq->num; | |
1301 | used = vq->used->ring + start; | |
dfe5ac5b | 1302 | if (__copy_to_user(used, heads, count * sizeof *used)) { |
8dd014ad DS |
1303 | vq_err(vq, "Failed to write used"); |
1304 | return -EFAULT; | |
1305 | } | |
1306 | if (unlikely(vq->log_used)) { | |
1307 | /* Make sure data is seen before log. */ | |
1308 | smp_wmb(); | |
1309 | /* Log used ring entry write. */ | |
1310 | log_write(vq->log_base, | |
1311 | vq->log_addr + | |
1312 | ((void __user *)used - (void __user *)vq->used), | |
1313 | count * sizeof *used); | |
1314 | } | |
8ea8cf89 MT |
1315 | old = vq->last_used_idx; |
1316 | new = (vq->last_used_idx += count); | |
1317 | /* If the driver never bothers to signal in a very long while, | |
1318 | * used index might wrap around. If that happens, invalidate | |
1319 | * signalled_used index we stored. TODO: make sure driver | |
1320 | * signals at least once in 2^16 and remove this. */ | |
1321 | if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old))) | |
1322 | vq->signalled_used_valid = false; | |
8dd014ad DS |
1323 | return 0; |
1324 | } | |
1325 | ||
1326 | /* After we've used one of their buffers, we tell them about it. We'll then | |
1327 | * want to notify the guest, using eventfd. */ | |
1328 | int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads, | |
1329 | unsigned count) | |
1330 | { | |
1331 | int start, n, r; | |
1332 | ||
1333 | start = vq->last_used_idx % vq->num; | |
1334 | n = vq->num - start; | |
1335 | if (n < count) { | |
1336 | r = __vhost_add_used_n(vq, heads, n); | |
1337 | if (r < 0) | |
1338 | return r; | |
1339 | heads += n; | |
1340 | count -= n; | |
1341 | } | |
1342 | r = __vhost_add_used_n(vq, heads, count); | |
1343 | ||
1344 | /* Make sure buffer is written before we update index. */ | |
1345 | smp_wmb(); | |
1346 | if (put_user(vq->last_used_idx, &vq->used->idx)) { | |
1347 | vq_err(vq, "Failed to increment used idx"); | |
1348 | return -EFAULT; | |
1349 | } | |
1350 | if (unlikely(vq->log_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 | return r; | |
1359 | } | |
1360 | ||
8ea8cf89 | 1361 | static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
3a4d5c94 | 1362 | { |
8ea8cf89 MT |
1363 | __u16 old, new, event; |
1364 | bool v; | |
0d499356 MT |
1365 | /* Flush out used index updates. This is paired |
1366 | * with the barrier that the Guest executes when enabling | |
1367 | * interrupts. */ | |
1368 | smp_mb(); | |
1369 | ||
8ea8cf89 MT |
1370 | if (vhost_has_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY) && |
1371 | unlikely(vq->avail_idx == vq->last_avail_idx)) | |
1372 | return true; | |
1373 | ||
1374 | if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { | |
1375 | __u16 flags; | |
1376 | if (__get_user(flags, &vq->avail->flags)) { | |
1377 | vq_err(vq, "Failed to get flags"); | |
1378 | return true; | |
1379 | } | |
1380 | return !(flags & VRING_AVAIL_F_NO_INTERRUPT); | |
3a4d5c94 | 1381 | } |
8ea8cf89 MT |
1382 | old = vq->signalled_used; |
1383 | v = vq->signalled_used_valid; | |
1384 | new = vq->signalled_used = vq->last_used_idx; | |
1385 | vq->signalled_used_valid = true; | |
3a4d5c94 | 1386 | |
8ea8cf89 MT |
1387 | if (unlikely(!v)) |
1388 | return true; | |
3a4d5c94 | 1389 | |
8ea8cf89 MT |
1390 | if (get_user(event, vhost_used_event(vq))) { |
1391 | vq_err(vq, "Failed to get used event idx"); | |
1392 | return true; | |
1393 | } | |
1394 | return vring_need_event(event, new, old); | |
1395 | } | |
1396 | ||
1397 | /* This actually signals the guest, using eventfd. */ | |
1398 | void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq) | |
1399 | { | |
3a4d5c94 | 1400 | /* Signal the Guest tell them we used something up. */ |
8ea8cf89 | 1401 | if (vq->call_ctx && vhost_notify(dev, vq)) |
3a4d5c94 MT |
1402 | eventfd_signal(vq->call_ctx, 1); |
1403 | } | |
1404 | ||
1405 | /* And here's the combo meal deal. Supersize me! */ | |
1406 | void vhost_add_used_and_signal(struct vhost_dev *dev, | |
1407 | struct vhost_virtqueue *vq, | |
1408 | unsigned int head, int len) | |
1409 | { | |
1410 | vhost_add_used(vq, head, len); | |
1411 | vhost_signal(dev, vq); | |
1412 | } | |
1413 | ||
8dd014ad DS |
1414 | /* multi-buffer version of vhost_add_used_and_signal */ |
1415 | void vhost_add_used_and_signal_n(struct vhost_dev *dev, | |
1416 | struct vhost_virtqueue *vq, | |
1417 | struct vring_used_elem *heads, unsigned count) | |
1418 | { | |
1419 | vhost_add_used_n(vq, heads, count); | |
1420 | vhost_signal(dev, vq); | |
1421 | } | |
1422 | ||
3a4d5c94 | 1423 | /* OK, now we need to know about added descriptors. */ |
8ea8cf89 | 1424 | bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
3a4d5c94 MT |
1425 | { |
1426 | u16 avail_idx; | |
1427 | int r; | |
d47effe1 | 1428 | |
3a4d5c94 MT |
1429 | if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY)) |
1430 | return false; | |
1431 | vq->used_flags &= ~VRING_USED_F_NO_NOTIFY; | |
8ea8cf89 MT |
1432 | if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { |
1433 | r = put_user(vq->used_flags, &vq->used->flags); | |
1434 | if (r) { | |
1435 | vq_err(vq, "Failed to enable notification at %p: %d\n", | |
1436 | &vq->used->flags, r); | |
1437 | return false; | |
1438 | } | |
1439 | } else { | |
1440 | r = put_user(vq->avail_idx, vhost_avail_event(vq)); | |
1441 | if (r) { | |
1442 | vq_err(vq, "Failed to update avail event index at %p: %d\n", | |
1443 | vhost_avail_event(vq), r); | |
1444 | return false; | |
1445 | } | |
1446 | } | |
1447 | if (unlikely(vq->log_used)) { | |
1448 | void __user *used; | |
1449 | /* Make sure data is seen before log. */ | |
1450 | smp_wmb(); | |
1451 | used = vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX) ? | |
1452 | &vq->used->flags : vhost_avail_event(vq); | |
1453 | /* Log used flags or event index entry write. Both are 16 bit | |
1454 | * fields. */ | |
1455 | log_write(vq->log_base, vq->log_addr + | |
1456 | (used - (void __user *)vq->used), | |
1457 | sizeof(u16)); | |
1458 | if (vq->log_ctx) | |
1459 | eventfd_signal(vq->log_ctx, 1); | |
3a4d5c94 MT |
1460 | } |
1461 | /* They could have slipped one in as we were doing that: make | |
1462 | * sure it's written, then check again. */ | |
5659338c | 1463 | smp_mb(); |
8b7347aa | 1464 | r = __get_user(avail_idx, &vq->avail->idx); |
3a4d5c94 MT |
1465 | if (r) { |
1466 | vq_err(vq, "Failed to check avail idx at %p: %d\n", | |
1467 | &vq->avail->idx, r); | |
1468 | return false; | |
1469 | } | |
1470 | ||
8dd014ad | 1471 | return avail_idx != vq->avail_idx; |
3a4d5c94 MT |
1472 | } |
1473 | ||
1474 | /* We don't need to be notified again. */ | |
8ea8cf89 | 1475 | void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
3a4d5c94 MT |
1476 | { |
1477 | int r; | |
d47effe1 | 1478 | |
3a4d5c94 MT |
1479 | if (vq->used_flags & VRING_USED_F_NO_NOTIFY) |
1480 | return; | |
1481 | vq->used_flags |= VRING_USED_F_NO_NOTIFY; | |
8ea8cf89 MT |
1482 | if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { |
1483 | r = put_user(vq->used_flags, &vq->used->flags); | |
1484 | if (r) | |
1485 | vq_err(vq, "Failed to enable notification at %p: %d\n", | |
1486 | &vq->used->flags, r); | |
1487 | } | |
3a4d5c94 | 1488 | } |