Commit | Line | Data |
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3a4d5c94 MT |
1 | /* Copyright (C) 2009 Red Hat, Inc. |
2 | * Copyright (C) 2006 Rusty Russell IBM Corporation | |
3 | * | |
4 | * Author: Michael S. Tsirkin <mst@redhat.com> | |
5 | * | |
6 | * Inspiration, some code, and most witty comments come from | |
61516587 | 7 | * Documentation/virtual/lguest/lguest.c, by Rusty Russell |
3a4d5c94 MT |
8 | * |
9 | * This work is licensed under the terms of the GNU GPL, version 2. | |
10 | * | |
11 | * Generic code for virtio server in host kernel. | |
12 | */ | |
13 | ||
14 | #include <linux/eventfd.h> | |
15 | #include <linux/vhost.h> | |
7542a6b0 | 16 | #include <linux/socket.h> /* memcpy_fromiovec */ |
3a4d5c94 | 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> |
6ac1afbf | 28 | #include <linux/module.h> |
3a4d5c94 | 29 | |
3a4d5c94 MT |
30 | #include "vhost.h" |
31 | ||
32 | enum { | |
33 | VHOST_MEMORY_MAX_NREGIONS = 64, | |
34 | VHOST_MEMORY_F_LOG = 0x1, | |
35 | }; | |
36 | ||
8ea8cf89 MT |
37 | #define vhost_used_event(vq) ((u16 __user *)&vq->avail->ring[vq->num]) |
38 | #define vhost_avail_event(vq) ((u16 __user *)&vq->used->ring[vq->num]) | |
39 | ||
3a4d5c94 MT |
40 | static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh, |
41 | poll_table *pt) | |
42 | { | |
43 | struct vhost_poll *poll; | |
3a4d5c94 | 44 | |
d47effe1 | 45 | poll = container_of(pt, struct vhost_poll, table); |
3a4d5c94 MT |
46 | poll->wqh = wqh; |
47 | add_wait_queue(wqh, &poll->wait); | |
48 | } | |
49 | ||
50 | static int vhost_poll_wakeup(wait_queue_t *wait, unsigned mode, int sync, | |
51 | void *key) | |
52 | { | |
c23f3445 TH |
53 | struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait); |
54 | ||
3a4d5c94 MT |
55 | if (!((unsigned long)key & poll->mask)) |
56 | return 0; | |
57 | ||
c23f3445 | 58 | vhost_poll_queue(poll); |
3a4d5c94 MT |
59 | return 0; |
60 | } | |
61 | ||
163049ae | 62 | void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn) |
87d6a412 MT |
63 | { |
64 | INIT_LIST_HEAD(&work->node); | |
65 | work->fn = fn; | |
66 | init_waitqueue_head(&work->done); | |
67 | work->flushing = 0; | |
68 | work->queue_seq = work->done_seq = 0; | |
69 | } | |
6ac1afbf | 70 | EXPORT_SYMBOL_GPL(vhost_work_init); |
87d6a412 | 71 | |
3a4d5c94 | 72 | /* Init poll structure */ |
c23f3445 TH |
73 | void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, |
74 | unsigned long mask, struct vhost_dev *dev) | |
3a4d5c94 | 75 | { |
3a4d5c94 MT |
76 | init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup); |
77 | init_poll_funcptr(&poll->table, vhost_poll_func); | |
78 | poll->mask = mask; | |
c23f3445 | 79 | poll->dev = dev; |
2b8b328b | 80 | poll->wqh = NULL; |
c23f3445 | 81 | |
87d6a412 | 82 | vhost_work_init(&poll->work, fn); |
3a4d5c94 | 83 | } |
6ac1afbf | 84 | EXPORT_SYMBOL_GPL(vhost_poll_init); |
3a4d5c94 MT |
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. */ | |
2b8b328b | 88 | int vhost_poll_start(struct vhost_poll *poll, struct file *file) |
3a4d5c94 MT |
89 | { |
90 | unsigned long mask; | |
2b8b328b | 91 | int ret = 0; |
d47effe1 | 92 | |
70181d51 JW |
93 | if (poll->wqh) |
94 | return 0; | |
95 | ||
3a4d5c94 MT |
96 | mask = file->f_op->poll(file, &poll->table); |
97 | if (mask) | |
98 | vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask); | |
2b8b328b JW |
99 | if (mask & POLLERR) { |
100 | if (poll->wqh) | |
101 | remove_wait_queue(poll->wqh, &poll->wait); | |
102 | ret = -EINVAL; | |
103 | } | |
104 | ||
105 | return ret; | |
3a4d5c94 | 106 | } |
6ac1afbf | 107 | EXPORT_SYMBOL_GPL(vhost_poll_start); |
3a4d5c94 MT |
108 | |
109 | /* Stop polling a file. After this function returns, it becomes safe to drop the | |
110 | * file reference. You must also flush afterwards. */ | |
111 | void vhost_poll_stop(struct vhost_poll *poll) | |
112 | { | |
2b8b328b JW |
113 | if (poll->wqh) { |
114 | remove_wait_queue(poll->wqh, &poll->wait); | |
115 | poll->wqh = NULL; | |
116 | } | |
3a4d5c94 | 117 | } |
6ac1afbf | 118 | EXPORT_SYMBOL_GPL(vhost_poll_stop); |
3a4d5c94 | 119 | |
0174b0c3 MT |
120 | static bool vhost_work_seq_done(struct vhost_dev *dev, struct vhost_work *work, |
121 | unsigned seq) | |
122 | { | |
123 | int left; | |
d47effe1 | 124 | |
0174b0c3 MT |
125 | spin_lock_irq(&dev->work_lock); |
126 | left = seq - work->done_seq; | |
127 | spin_unlock_irq(&dev->work_lock); | |
128 | return left <= 0; | |
129 | } | |
130 | ||
6ac1afbf | 131 | void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work) |
3a4d5c94 | 132 | { |
c23f3445 | 133 | unsigned seq; |
c23f3445 TH |
134 | int flushing; |
135 | ||
87d6a412 | 136 | spin_lock_irq(&dev->work_lock); |
c23f3445 TH |
137 | seq = work->queue_seq; |
138 | work->flushing++; | |
87d6a412 | 139 | spin_unlock_irq(&dev->work_lock); |
0174b0c3 | 140 | wait_event(work->done, vhost_work_seq_done(dev, work, seq)); |
87d6a412 | 141 | spin_lock_irq(&dev->work_lock); |
c23f3445 | 142 | flushing = --work->flushing; |
87d6a412 | 143 | spin_unlock_irq(&dev->work_lock); |
c23f3445 | 144 | BUG_ON(flushing < 0); |
3a4d5c94 | 145 | } |
6ac1afbf | 146 | EXPORT_SYMBOL_GPL(vhost_work_flush); |
3a4d5c94 | 147 | |
87d6a412 MT |
148 | /* Flush any work that has been scheduled. When calling this, don't hold any |
149 | * locks that are also used by the callback. */ | |
150 | void vhost_poll_flush(struct vhost_poll *poll) | |
151 | { | |
152 | vhost_work_flush(poll->dev, &poll->work); | |
153 | } | |
6ac1afbf | 154 | EXPORT_SYMBOL_GPL(vhost_poll_flush); |
87d6a412 | 155 | |
163049ae | 156 | void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work) |
3a4d5c94 | 157 | { |
c23f3445 TH |
158 | unsigned long flags; |
159 | ||
160 | spin_lock_irqsave(&dev->work_lock, flags); | |
161 | if (list_empty(&work->node)) { | |
162 | list_add_tail(&work->node, &dev->work_list); | |
163 | work->queue_seq++; | |
164 | wake_up_process(dev->worker); | |
165 | } | |
166 | spin_unlock_irqrestore(&dev->work_lock, flags); | |
3a4d5c94 | 167 | } |
6ac1afbf | 168 | EXPORT_SYMBOL_GPL(vhost_work_queue); |
3a4d5c94 | 169 | |
87d6a412 MT |
170 | void vhost_poll_queue(struct vhost_poll *poll) |
171 | { | |
172 | vhost_work_queue(poll->dev, &poll->work); | |
173 | } | |
6ac1afbf | 174 | EXPORT_SYMBOL_GPL(vhost_poll_queue); |
87d6a412 | 175 | |
3a4d5c94 MT |
176 | static void vhost_vq_reset(struct vhost_dev *dev, |
177 | struct vhost_virtqueue *vq) | |
178 | { | |
179 | vq->num = 1; | |
180 | vq->desc = NULL; | |
181 | vq->avail = NULL; | |
182 | vq->used = NULL; | |
183 | vq->last_avail_idx = 0; | |
184 | vq->avail_idx = 0; | |
185 | vq->last_used_idx = 0; | |
8ea8cf89 MT |
186 | vq->signalled_used = 0; |
187 | vq->signalled_used_valid = false; | |
3a4d5c94 | 188 | vq->used_flags = 0; |
3a4d5c94 MT |
189 | vq->log_used = false; |
190 | vq->log_addr = -1ull; | |
3a4d5c94 MT |
191 | vq->private_data = NULL; |
192 | vq->log_base = NULL; | |
193 | vq->error_ctx = NULL; | |
194 | vq->error = NULL; | |
195 | vq->kick = NULL; | |
196 | vq->call_ctx = NULL; | |
197 | vq->call = NULL; | |
73a99f08 | 198 | vq->log_ctx = NULL; |
3a4d5c94 MT |
199 | } |
200 | ||
c23f3445 TH |
201 | static int vhost_worker(void *data) |
202 | { | |
203 | struct vhost_dev *dev = data; | |
204 | struct vhost_work *work = NULL; | |
205 | unsigned uninitialized_var(seq); | |
d7ffde35 | 206 | mm_segment_t oldfs = get_fs(); |
c23f3445 | 207 | |
d7ffde35 | 208 | set_fs(USER_DS); |
64e1c807 MT |
209 | use_mm(dev->mm); |
210 | ||
c23f3445 TH |
211 | for (;;) { |
212 | /* mb paired w/ kthread_stop */ | |
213 | set_current_state(TASK_INTERRUPTIBLE); | |
214 | ||
215 | spin_lock_irq(&dev->work_lock); | |
216 | if (work) { | |
217 | work->done_seq = seq; | |
218 | if (work->flushing) | |
219 | wake_up_all(&work->done); | |
220 | } | |
221 | ||
222 | if (kthread_should_stop()) { | |
223 | spin_unlock_irq(&dev->work_lock); | |
224 | __set_current_state(TASK_RUNNING); | |
64e1c807 | 225 | break; |
c23f3445 TH |
226 | } |
227 | if (!list_empty(&dev->work_list)) { | |
228 | work = list_first_entry(&dev->work_list, | |
229 | struct vhost_work, node); | |
230 | list_del_init(&work->node); | |
231 | seq = work->queue_seq; | |
232 | } else | |
233 | work = NULL; | |
234 | spin_unlock_irq(&dev->work_lock); | |
235 | ||
236 | if (work) { | |
237 | __set_current_state(TASK_RUNNING); | |
238 | work->fn(work); | |
d550dda1 NHE |
239 | if (need_resched()) |
240 | schedule(); | |
c23f3445 TH |
241 | } else |
242 | schedule(); | |
243 | ||
244 | } | |
64e1c807 | 245 | unuse_mm(dev->mm); |
d7ffde35 | 246 | set_fs(oldfs); |
64e1c807 | 247 | return 0; |
c23f3445 TH |
248 | } |
249 | ||
bab632d6 MT |
250 | static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq) |
251 | { | |
252 | kfree(vq->indirect); | |
253 | vq->indirect = NULL; | |
254 | kfree(vq->log); | |
255 | vq->log = NULL; | |
256 | kfree(vq->heads); | |
257 | vq->heads = NULL; | |
bab632d6 MT |
258 | } |
259 | ||
e0e9b406 JW |
260 | /* Helper to allocate iovec buffers for all vqs. */ |
261 | static long vhost_dev_alloc_iovecs(struct vhost_dev *dev) | |
262 | { | |
6d5e6aa8 | 263 | struct vhost_virtqueue *vq; |
e0e9b406 | 264 | int i; |
d47effe1 | 265 | |
e0e9b406 | 266 | for (i = 0; i < dev->nvqs; ++i) { |
6d5e6aa8 AH |
267 | vq = dev->vqs[i]; |
268 | vq->indirect = kmalloc(sizeof *vq->indirect * UIO_MAXIOV, | |
269 | GFP_KERNEL); | |
270 | vq->log = kmalloc(sizeof *vq->log * UIO_MAXIOV, GFP_KERNEL); | |
271 | vq->heads = kmalloc(sizeof *vq->heads * UIO_MAXIOV, GFP_KERNEL); | |
272 | if (!vq->indirect || !vq->log || !vq->heads) | |
e0e9b406 JW |
273 | goto err_nomem; |
274 | } | |
275 | return 0; | |
d47effe1 | 276 | |
e0e9b406 | 277 | err_nomem: |
bab632d6 | 278 | for (; i >= 0; --i) |
3ab2e420 | 279 | vhost_vq_free_iovecs(dev->vqs[i]); |
e0e9b406 JW |
280 | return -ENOMEM; |
281 | } | |
282 | ||
283 | static void vhost_dev_free_iovecs(struct vhost_dev *dev) | |
284 | { | |
285 | int i; | |
d47effe1 | 286 | |
bab632d6 | 287 | for (i = 0; i < dev->nvqs; ++i) |
3ab2e420 | 288 | vhost_vq_free_iovecs(dev->vqs[i]); |
e0e9b406 JW |
289 | } |
290 | ||
3a4d5c94 | 291 | long vhost_dev_init(struct vhost_dev *dev, |
3ab2e420 | 292 | struct vhost_virtqueue **vqs, int nvqs) |
3a4d5c94 | 293 | { |
6d5e6aa8 | 294 | struct vhost_virtqueue *vq; |
3a4d5c94 | 295 | int i; |
c23f3445 | 296 | |
3a4d5c94 MT |
297 | dev->vqs = vqs; |
298 | dev->nvqs = nvqs; | |
299 | mutex_init(&dev->mutex); | |
300 | dev->log_ctx = NULL; | |
301 | dev->log_file = NULL; | |
302 | dev->memory = NULL; | |
303 | dev->mm = NULL; | |
c23f3445 TH |
304 | spin_lock_init(&dev->work_lock); |
305 | INIT_LIST_HEAD(&dev->work_list); | |
306 | dev->worker = NULL; | |
3a4d5c94 MT |
307 | |
308 | for (i = 0; i < dev->nvqs; ++i) { | |
6d5e6aa8 AH |
309 | vq = dev->vqs[i]; |
310 | vq->log = NULL; | |
311 | vq->indirect = NULL; | |
312 | vq->heads = NULL; | |
313 | vq->dev = dev; | |
314 | mutex_init(&vq->mutex); | |
315 | vhost_vq_reset(dev, vq); | |
316 | if (vq->handle_kick) | |
317 | vhost_poll_init(&vq->poll, vq->handle_kick, | |
318 | POLLIN, dev); | |
3a4d5c94 | 319 | } |
c23f3445 | 320 | |
3a4d5c94 MT |
321 | return 0; |
322 | } | |
6ac1afbf | 323 | EXPORT_SYMBOL_GPL(vhost_dev_init); |
3a4d5c94 MT |
324 | |
325 | /* Caller should have device mutex */ | |
326 | long vhost_dev_check_owner(struct vhost_dev *dev) | |
327 | { | |
328 | /* Are you the owner? If not, I don't think you mean to do that */ | |
329 | return dev->mm == current->mm ? 0 : -EPERM; | |
330 | } | |
6ac1afbf | 331 | EXPORT_SYMBOL_GPL(vhost_dev_check_owner); |
3a4d5c94 | 332 | |
87d6a412 | 333 | struct vhost_attach_cgroups_struct { |
d47effe1 KK |
334 | struct vhost_work work; |
335 | struct task_struct *owner; | |
336 | int ret; | |
87d6a412 MT |
337 | }; |
338 | ||
339 | static void vhost_attach_cgroups_work(struct vhost_work *work) | |
340 | { | |
d47effe1 KK |
341 | struct vhost_attach_cgroups_struct *s; |
342 | ||
343 | s = container_of(work, struct vhost_attach_cgroups_struct, work); | |
344 | s->ret = cgroup_attach_task_all(s->owner, current); | |
87d6a412 MT |
345 | } |
346 | ||
347 | static int vhost_attach_cgroups(struct vhost_dev *dev) | |
348 | { | |
d47effe1 KK |
349 | struct vhost_attach_cgroups_struct attach; |
350 | ||
351 | attach.owner = current; | |
352 | vhost_work_init(&attach.work, vhost_attach_cgroups_work); | |
353 | vhost_work_queue(dev, &attach.work); | |
354 | vhost_work_flush(dev, &attach.work); | |
355 | return attach.ret; | |
87d6a412 MT |
356 | } |
357 | ||
05c05351 MT |
358 | /* Caller should have device mutex */ |
359 | bool vhost_dev_has_owner(struct vhost_dev *dev) | |
360 | { | |
361 | return dev->mm; | |
362 | } | |
6ac1afbf | 363 | EXPORT_SYMBOL_GPL(vhost_dev_has_owner); |
05c05351 | 364 | |
3a4d5c94 | 365 | /* Caller should have device mutex */ |
54db63c2 | 366 | long vhost_dev_set_owner(struct vhost_dev *dev) |
3a4d5c94 | 367 | { |
c23f3445 TH |
368 | struct task_struct *worker; |
369 | int err; | |
d47effe1 | 370 | |
3a4d5c94 | 371 | /* Is there an owner already? */ |
05c05351 | 372 | if (vhost_dev_has_owner(dev)) { |
c23f3445 TH |
373 | err = -EBUSY; |
374 | goto err_mm; | |
375 | } | |
d47effe1 | 376 | |
3a4d5c94 MT |
377 | /* No owner, become one */ |
378 | dev->mm = get_task_mm(current); | |
c23f3445 TH |
379 | worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid); |
380 | if (IS_ERR(worker)) { | |
381 | err = PTR_ERR(worker); | |
382 | goto err_worker; | |
383 | } | |
384 | ||
385 | dev->worker = worker; | |
87d6a412 MT |
386 | wake_up_process(worker); /* avoid contributing to loadavg */ |
387 | ||
388 | err = vhost_attach_cgroups(dev); | |
9e3d1957 MT |
389 | if (err) |
390 | goto err_cgroup; | |
c23f3445 | 391 | |
e0e9b406 JW |
392 | err = vhost_dev_alloc_iovecs(dev); |
393 | if (err) | |
394 | goto err_cgroup; | |
395 | ||
3a4d5c94 | 396 | return 0; |
9e3d1957 MT |
397 | err_cgroup: |
398 | kthread_stop(worker); | |
615cc221 | 399 | dev->worker = NULL; |
c23f3445 TH |
400 | err_worker: |
401 | if (dev->mm) | |
402 | mmput(dev->mm); | |
403 | dev->mm = NULL; | |
404 | err_mm: | |
405 | return err; | |
3a4d5c94 | 406 | } |
6ac1afbf | 407 | EXPORT_SYMBOL_GPL(vhost_dev_set_owner); |
3a4d5c94 | 408 | |
150b9e51 | 409 | struct vhost_memory *vhost_dev_reset_owner_prepare(void) |
3a4d5c94 | 410 | { |
150b9e51 MT |
411 | return kmalloc(offsetof(struct vhost_memory, regions), GFP_KERNEL); |
412 | } | |
6ac1afbf | 413 | EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare); |
3a4d5c94 | 414 | |
150b9e51 MT |
415 | /* Caller should have device mutex */ |
416 | void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_memory *memory) | |
417 | { | |
ea5d4046 | 418 | vhost_dev_cleanup(dev, true); |
3a4d5c94 | 419 | |
150b9e51 | 420 | /* Restore memory to default empty mapping. */ |
3a4d5c94 | 421 | memory->nregions = 0; |
28457ee6 | 422 | RCU_INIT_POINTER(dev->memory, memory); |
3a4d5c94 | 423 | } |
6ac1afbf | 424 | EXPORT_SYMBOL_GPL(vhost_dev_reset_owner); |
3a4d5c94 | 425 | |
b211616d | 426 | void vhost_dev_stop(struct vhost_dev *dev) |
bab632d6 MT |
427 | { |
428 | int i; | |
b211616d MT |
429 | |
430 | for (i = 0; i < dev->nvqs; ++i) { | |
3ab2e420 AH |
431 | if (dev->vqs[i]->kick && dev->vqs[i]->handle_kick) { |
432 | vhost_poll_stop(&dev->vqs[i]->poll); | |
433 | vhost_poll_flush(&dev->vqs[i]->poll); | |
b211616d | 434 | } |
bab632d6 | 435 | } |
bab632d6 | 436 | } |
6ac1afbf | 437 | EXPORT_SYMBOL_GPL(vhost_dev_stop); |
bab632d6 | 438 | |
ea5d4046 MT |
439 | /* Caller should have device mutex if and only if locked is set */ |
440 | void vhost_dev_cleanup(struct vhost_dev *dev, bool locked) | |
3a4d5c94 MT |
441 | { |
442 | int i; | |
d47effe1 | 443 | |
3a4d5c94 | 444 | for (i = 0; i < dev->nvqs; ++i) { |
3ab2e420 AH |
445 | if (dev->vqs[i]->error_ctx) |
446 | eventfd_ctx_put(dev->vqs[i]->error_ctx); | |
447 | if (dev->vqs[i]->error) | |
448 | fput(dev->vqs[i]->error); | |
449 | if (dev->vqs[i]->kick) | |
450 | fput(dev->vqs[i]->kick); | |
451 | if (dev->vqs[i]->call_ctx) | |
452 | eventfd_ctx_put(dev->vqs[i]->call_ctx); | |
453 | if (dev->vqs[i]->call) | |
454 | fput(dev->vqs[i]->call); | |
455 | vhost_vq_reset(dev, dev->vqs[i]); | |
3a4d5c94 | 456 | } |
e0e9b406 | 457 | vhost_dev_free_iovecs(dev); |
3a4d5c94 MT |
458 | if (dev->log_ctx) |
459 | eventfd_ctx_put(dev->log_ctx); | |
460 | dev->log_ctx = NULL; | |
461 | if (dev->log_file) | |
462 | fput(dev->log_file); | |
463 | dev->log_file = NULL; | |
464 | /* No one will access memory at this point */ | |
28457ee6 | 465 | kfree(rcu_dereference_protected(dev->memory, |
ea5d4046 MT |
466 | locked == |
467 | lockdep_is_held(&dev->mutex))); | |
28457ee6 | 468 | RCU_INIT_POINTER(dev->memory, NULL); |
c23f3445 | 469 | WARN_ON(!list_empty(&dev->work_list)); |
78b620ce ED |
470 | if (dev->worker) { |
471 | kthread_stop(dev->worker); | |
472 | dev->worker = NULL; | |
473 | } | |
533a19b4 MT |
474 | if (dev->mm) |
475 | mmput(dev->mm); | |
476 | dev->mm = NULL; | |
3a4d5c94 | 477 | } |
6ac1afbf | 478 | EXPORT_SYMBOL_GPL(vhost_dev_cleanup); |
3a4d5c94 MT |
479 | |
480 | static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz) | |
481 | { | |
482 | u64 a = addr / VHOST_PAGE_SIZE / 8; | |
d47effe1 | 483 | |
3a4d5c94 MT |
484 | /* Make sure 64 bit math will not overflow. */ |
485 | if (a > ULONG_MAX - (unsigned long)log_base || | |
486 | a + (unsigned long)log_base > ULONG_MAX) | |
6d97e55f | 487 | return 0; |
3a4d5c94 MT |
488 | |
489 | return access_ok(VERIFY_WRITE, log_base + a, | |
490 | (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8); | |
491 | } | |
492 | ||
493 | /* Caller should have vq mutex and device mutex. */ | |
494 | static int vq_memory_access_ok(void __user *log_base, struct vhost_memory *mem, | |
495 | int log_all) | |
496 | { | |
497 | int i; | |
179b284e | 498 | |
f8322fbe MT |
499 | if (!mem) |
500 | return 0; | |
179b284e | 501 | |
3a4d5c94 MT |
502 | for (i = 0; i < mem->nregions; ++i) { |
503 | struct vhost_memory_region *m = mem->regions + i; | |
504 | unsigned long a = m->userspace_addr; | |
505 | if (m->memory_size > ULONG_MAX) | |
506 | return 0; | |
507 | else if (!access_ok(VERIFY_WRITE, (void __user *)a, | |
508 | m->memory_size)) | |
509 | return 0; | |
510 | else if (log_all && !log_access_ok(log_base, | |
511 | m->guest_phys_addr, | |
512 | m->memory_size)) | |
513 | return 0; | |
514 | } | |
515 | return 1; | |
516 | } | |
517 | ||
518 | /* Can we switch to this memory table? */ | |
519 | /* Caller should have device mutex but not vq mutex */ | |
520 | static int memory_access_ok(struct vhost_dev *d, struct vhost_memory *mem, | |
521 | int log_all) | |
522 | { | |
523 | int i; | |
d47effe1 | 524 | |
3a4d5c94 MT |
525 | for (i = 0; i < d->nvqs; ++i) { |
526 | int ok; | |
3ab2e420 | 527 | mutex_lock(&d->vqs[i]->mutex); |
3a4d5c94 | 528 | /* If ring is inactive, will check when it's enabled. */ |
3ab2e420 AH |
529 | if (d->vqs[i]->private_data) |
530 | ok = vq_memory_access_ok(d->vqs[i]->log_base, mem, | |
3a4d5c94 MT |
531 | log_all); |
532 | else | |
533 | ok = 1; | |
3ab2e420 | 534 | mutex_unlock(&d->vqs[i]->mutex); |
3a4d5c94 MT |
535 | if (!ok) |
536 | return 0; | |
537 | } | |
538 | return 1; | |
539 | } | |
540 | ||
8ea8cf89 | 541 | static int vq_access_ok(struct vhost_dev *d, unsigned int num, |
3a4d5c94 MT |
542 | struct vring_desc __user *desc, |
543 | struct vring_avail __user *avail, | |
544 | struct vring_used __user *used) | |
545 | { | |
8ea8cf89 | 546 | size_t s = vhost_has_feature(d, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; |
3a4d5c94 MT |
547 | return access_ok(VERIFY_READ, desc, num * sizeof *desc) && |
548 | access_ok(VERIFY_READ, avail, | |
8ea8cf89 | 549 | sizeof *avail + num * sizeof *avail->ring + s) && |
3a4d5c94 | 550 | access_ok(VERIFY_WRITE, used, |
8ea8cf89 | 551 | sizeof *used + num * sizeof *used->ring + s); |
3a4d5c94 MT |
552 | } |
553 | ||
554 | /* Can we log writes? */ | |
555 | /* Caller should have device mutex but not vq mutex */ | |
556 | int vhost_log_access_ok(struct vhost_dev *dev) | |
557 | { | |
28457ee6 AB |
558 | struct vhost_memory *mp; |
559 | ||
560 | mp = rcu_dereference_protected(dev->memory, | |
561 | lockdep_is_held(&dev->mutex)); | |
562 | return memory_access_ok(dev, mp, 1); | |
3a4d5c94 | 563 | } |
6ac1afbf | 564 | EXPORT_SYMBOL_GPL(vhost_log_access_ok); |
3a4d5c94 MT |
565 | |
566 | /* Verify access for write logging. */ | |
567 | /* Caller should have vq mutex and device mutex */ | |
8ea8cf89 MT |
568 | static int vq_log_access_ok(struct vhost_dev *d, struct vhost_virtqueue *vq, |
569 | void __user *log_base) | |
3a4d5c94 | 570 | { |
28457ee6 | 571 | struct vhost_memory *mp; |
8ea8cf89 | 572 | size_t s = vhost_has_feature(d, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; |
28457ee6 AB |
573 | |
574 | mp = rcu_dereference_protected(vq->dev->memory, | |
575 | lockdep_is_held(&vq->mutex)); | |
576 | return vq_memory_access_ok(log_base, mp, | |
3a4d5c94 MT |
577 | vhost_has_feature(vq->dev, VHOST_F_LOG_ALL)) && |
578 | (!vq->log_used || log_access_ok(log_base, vq->log_addr, | |
579 | sizeof *vq->used + | |
8ea8cf89 | 580 | vq->num * sizeof *vq->used->ring + s)); |
3a4d5c94 MT |
581 | } |
582 | ||
583 | /* Can we start vq? */ | |
584 | /* Caller should have vq mutex and device mutex */ | |
585 | int vhost_vq_access_ok(struct vhost_virtqueue *vq) | |
586 | { | |
8ea8cf89 MT |
587 | return vq_access_ok(vq->dev, vq->num, vq->desc, vq->avail, vq->used) && |
588 | vq_log_access_ok(vq->dev, vq, vq->log_base); | |
3a4d5c94 | 589 | } |
6ac1afbf | 590 | EXPORT_SYMBOL_GPL(vhost_vq_access_ok); |
3a4d5c94 MT |
591 | |
592 | static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) | |
593 | { | |
594 | struct vhost_memory mem, *newmem, *oldmem; | |
595 | unsigned long size = offsetof(struct vhost_memory, regions); | |
d47effe1 | 596 | |
7ad9c9d2 TY |
597 | if (copy_from_user(&mem, m, size)) |
598 | return -EFAULT; | |
3a4d5c94 MT |
599 | if (mem.padding) |
600 | return -EOPNOTSUPP; | |
601 | if (mem.nregions > VHOST_MEMORY_MAX_NREGIONS) | |
602 | return -E2BIG; | |
603 | newmem = kmalloc(size + mem.nregions * sizeof *m->regions, GFP_KERNEL); | |
604 | if (!newmem) | |
605 | return -ENOMEM; | |
606 | ||
607 | memcpy(newmem, &mem, size); | |
7ad9c9d2 TY |
608 | if (copy_from_user(newmem->regions, m->regions, |
609 | mem.nregions * sizeof *m->regions)) { | |
3a4d5c94 | 610 | kfree(newmem); |
7ad9c9d2 | 611 | return -EFAULT; |
3a4d5c94 MT |
612 | } |
613 | ||
d47effe1 KK |
614 | if (!memory_access_ok(d, newmem, |
615 | vhost_has_feature(d, VHOST_F_LOG_ALL))) { | |
a02c3789 | 616 | kfree(newmem); |
3a4d5c94 | 617 | return -EFAULT; |
a02c3789 | 618 | } |
28457ee6 AB |
619 | oldmem = rcu_dereference_protected(d->memory, |
620 | lockdep_is_held(&d->mutex)); | |
3a4d5c94 MT |
621 | rcu_assign_pointer(d->memory, newmem); |
622 | synchronize_rcu(); | |
623 | kfree(oldmem); | |
624 | return 0; | |
625 | } | |
626 | ||
935cdee7 | 627 | long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp) |
3a4d5c94 | 628 | { |
cecb46f1 AV |
629 | struct file *eventfp, *filep = NULL; |
630 | bool pollstart = false, pollstop = false; | |
3a4d5c94 MT |
631 | struct eventfd_ctx *ctx = NULL; |
632 | u32 __user *idxp = argp; | |
633 | struct vhost_virtqueue *vq; | |
634 | struct vhost_vring_state s; | |
635 | struct vhost_vring_file f; | |
636 | struct vhost_vring_addr a; | |
637 | u32 idx; | |
638 | long r; | |
639 | ||
640 | r = get_user(idx, idxp); | |
641 | if (r < 0) | |
642 | return r; | |
0f3d9a17 | 643 | if (idx >= d->nvqs) |
3a4d5c94 MT |
644 | return -ENOBUFS; |
645 | ||
3ab2e420 | 646 | vq = d->vqs[idx]; |
3a4d5c94 MT |
647 | |
648 | mutex_lock(&vq->mutex); | |
649 | ||
650 | switch (ioctl) { | |
651 | case VHOST_SET_VRING_NUM: | |
652 | /* Resizing ring with an active backend? | |
653 | * You don't want to do that. */ | |
654 | if (vq->private_data) { | |
655 | r = -EBUSY; | |
656 | break; | |
657 | } | |
7ad9c9d2 TY |
658 | if (copy_from_user(&s, argp, sizeof s)) { |
659 | r = -EFAULT; | |
3a4d5c94 | 660 | break; |
7ad9c9d2 | 661 | } |
3a4d5c94 MT |
662 | if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) { |
663 | r = -EINVAL; | |
664 | break; | |
665 | } | |
666 | vq->num = s.num; | |
667 | break; | |
668 | case VHOST_SET_VRING_BASE: | |
669 | /* Moving base with an active backend? | |
670 | * You don't want to do that. */ | |
671 | if (vq->private_data) { | |
672 | r = -EBUSY; | |
673 | break; | |
674 | } | |
7ad9c9d2 TY |
675 | if (copy_from_user(&s, argp, sizeof s)) { |
676 | r = -EFAULT; | |
3a4d5c94 | 677 | break; |
7ad9c9d2 | 678 | } |
3a4d5c94 MT |
679 | if (s.num > 0xffff) { |
680 | r = -EINVAL; | |
681 | break; | |
682 | } | |
683 | vq->last_avail_idx = s.num; | |
684 | /* Forget the cached index value. */ | |
685 | vq->avail_idx = vq->last_avail_idx; | |
686 | break; | |
687 | case VHOST_GET_VRING_BASE: | |
688 | s.index = idx; | |
689 | s.num = vq->last_avail_idx; | |
7ad9c9d2 TY |
690 | if (copy_to_user(argp, &s, sizeof s)) |
691 | r = -EFAULT; | |
3a4d5c94 MT |
692 | break; |
693 | case VHOST_SET_VRING_ADDR: | |
7ad9c9d2 TY |
694 | if (copy_from_user(&a, argp, sizeof a)) { |
695 | r = -EFAULT; | |
3a4d5c94 | 696 | break; |
7ad9c9d2 | 697 | } |
3a4d5c94 MT |
698 | if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) { |
699 | r = -EOPNOTSUPP; | |
700 | break; | |
701 | } | |
702 | /* For 32bit, verify that the top 32bits of the user | |
703 | data are set to zero. */ | |
704 | if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr || | |
705 | (u64)(unsigned long)a.used_user_addr != a.used_user_addr || | |
706 | (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) { | |
707 | r = -EFAULT; | |
708 | break; | |
709 | } | |
710 | if ((a.avail_user_addr & (sizeof *vq->avail->ring - 1)) || | |
711 | (a.used_user_addr & (sizeof *vq->used->ring - 1)) || | |
712 | (a.log_guest_addr & (sizeof *vq->used->ring - 1))) { | |
713 | r = -EINVAL; | |
714 | break; | |
715 | } | |
716 | ||
717 | /* We only verify access here if backend is configured. | |
718 | * If it is not, we don't as size might not have been setup. | |
719 | * We will verify when backend is configured. */ | |
720 | if (vq->private_data) { | |
8ea8cf89 | 721 | if (!vq_access_ok(d, vq->num, |
3a4d5c94 MT |
722 | (void __user *)(unsigned long)a.desc_user_addr, |
723 | (void __user *)(unsigned long)a.avail_user_addr, | |
724 | (void __user *)(unsigned long)a.used_user_addr)) { | |
725 | r = -EINVAL; | |
726 | break; | |
727 | } | |
728 | ||
729 | /* Also validate log access for used ring if enabled. */ | |
730 | if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) && | |
731 | !log_access_ok(vq->log_base, a.log_guest_addr, | |
732 | sizeof *vq->used + | |
733 | vq->num * sizeof *vq->used->ring)) { | |
734 | r = -EINVAL; | |
735 | break; | |
736 | } | |
737 | } | |
738 | ||
3a4d5c94 MT |
739 | vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG)); |
740 | vq->desc = (void __user *)(unsigned long)a.desc_user_addr; | |
741 | vq->avail = (void __user *)(unsigned long)a.avail_user_addr; | |
742 | vq->log_addr = a.log_guest_addr; | |
743 | vq->used = (void __user *)(unsigned long)a.used_user_addr; | |
744 | break; | |
745 | case VHOST_SET_VRING_KICK: | |
7ad9c9d2 TY |
746 | if (copy_from_user(&f, argp, sizeof f)) { |
747 | r = -EFAULT; | |
3a4d5c94 | 748 | break; |
7ad9c9d2 | 749 | } |
3a4d5c94 | 750 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
751 | if (IS_ERR(eventfp)) { |
752 | r = PTR_ERR(eventfp); | |
753 | break; | |
754 | } | |
3a4d5c94 | 755 | if (eventfp != vq->kick) { |
cecb46f1 AV |
756 | pollstop = (filep = vq->kick) != NULL; |
757 | pollstart = (vq->kick = eventfp) != NULL; | |
3a4d5c94 MT |
758 | } else |
759 | filep = eventfp; | |
760 | break; | |
761 | case VHOST_SET_VRING_CALL: | |
7ad9c9d2 TY |
762 | if (copy_from_user(&f, argp, sizeof f)) { |
763 | r = -EFAULT; | |
3a4d5c94 | 764 | break; |
7ad9c9d2 | 765 | } |
3a4d5c94 | 766 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
767 | if (IS_ERR(eventfp)) { |
768 | r = PTR_ERR(eventfp); | |
769 | break; | |
770 | } | |
3a4d5c94 MT |
771 | if (eventfp != vq->call) { |
772 | filep = vq->call; | |
773 | ctx = vq->call_ctx; | |
774 | vq->call = eventfp; | |
775 | vq->call_ctx = eventfp ? | |
776 | eventfd_ctx_fileget(eventfp) : NULL; | |
777 | } else | |
778 | filep = eventfp; | |
779 | break; | |
780 | case VHOST_SET_VRING_ERR: | |
7ad9c9d2 TY |
781 | if (copy_from_user(&f, argp, sizeof f)) { |
782 | r = -EFAULT; | |
3a4d5c94 | 783 | break; |
7ad9c9d2 | 784 | } |
3a4d5c94 | 785 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
786 | if (IS_ERR(eventfp)) { |
787 | r = PTR_ERR(eventfp); | |
788 | break; | |
789 | } | |
3a4d5c94 MT |
790 | if (eventfp != vq->error) { |
791 | filep = vq->error; | |
792 | vq->error = eventfp; | |
793 | ctx = vq->error_ctx; | |
794 | vq->error_ctx = eventfp ? | |
795 | eventfd_ctx_fileget(eventfp) : NULL; | |
796 | } else | |
797 | filep = eventfp; | |
798 | break; | |
799 | default: | |
800 | r = -ENOIOCTLCMD; | |
801 | } | |
802 | ||
803 | if (pollstop && vq->handle_kick) | |
804 | vhost_poll_stop(&vq->poll); | |
805 | ||
806 | if (ctx) | |
807 | eventfd_ctx_put(ctx); | |
808 | if (filep) | |
809 | fput(filep); | |
810 | ||
811 | if (pollstart && vq->handle_kick) | |
2b8b328b | 812 | r = vhost_poll_start(&vq->poll, vq->kick); |
3a4d5c94 MT |
813 | |
814 | mutex_unlock(&vq->mutex); | |
815 | ||
816 | if (pollstop && vq->handle_kick) | |
817 | vhost_poll_flush(&vq->poll); | |
818 | return r; | |
819 | } | |
6ac1afbf | 820 | EXPORT_SYMBOL_GPL(vhost_vring_ioctl); |
3a4d5c94 MT |
821 | |
822 | /* Caller must have device mutex */ | |
935cdee7 | 823 | long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp) |
3a4d5c94 | 824 | { |
3a4d5c94 MT |
825 | struct file *eventfp, *filep = NULL; |
826 | struct eventfd_ctx *ctx = NULL; | |
827 | u64 p; | |
828 | long r; | |
829 | int i, fd; | |
830 | ||
831 | /* If you are not the owner, you can become one */ | |
832 | if (ioctl == VHOST_SET_OWNER) { | |
833 | r = vhost_dev_set_owner(d); | |
834 | goto done; | |
835 | } | |
836 | ||
837 | /* You must be the owner to do anything else */ | |
838 | r = vhost_dev_check_owner(d); | |
839 | if (r) | |
840 | goto done; | |
841 | ||
842 | switch (ioctl) { | |
843 | case VHOST_SET_MEM_TABLE: | |
844 | r = vhost_set_memory(d, argp); | |
845 | break; | |
846 | case VHOST_SET_LOG_BASE: | |
7ad9c9d2 TY |
847 | if (copy_from_user(&p, argp, sizeof p)) { |
848 | r = -EFAULT; | |
3a4d5c94 | 849 | break; |
7ad9c9d2 | 850 | } |
3a4d5c94 MT |
851 | if ((u64)(unsigned long)p != p) { |
852 | r = -EFAULT; | |
853 | break; | |
854 | } | |
855 | for (i = 0; i < d->nvqs; ++i) { | |
856 | struct vhost_virtqueue *vq; | |
857 | void __user *base = (void __user *)(unsigned long)p; | |
3ab2e420 | 858 | vq = d->vqs[i]; |
3a4d5c94 MT |
859 | mutex_lock(&vq->mutex); |
860 | /* If ring is inactive, will check when it's enabled. */ | |
8ea8cf89 | 861 | if (vq->private_data && !vq_log_access_ok(d, vq, base)) |
3a4d5c94 MT |
862 | r = -EFAULT; |
863 | else | |
864 | vq->log_base = base; | |
865 | mutex_unlock(&vq->mutex); | |
866 | } | |
867 | break; | |
868 | case VHOST_SET_LOG_FD: | |
869 | r = get_user(fd, (int __user *)argp); | |
870 | if (r < 0) | |
871 | break; | |
872 | eventfp = fd == -1 ? NULL : eventfd_fget(fd); | |
873 | if (IS_ERR(eventfp)) { | |
874 | r = PTR_ERR(eventfp); | |
875 | break; | |
876 | } | |
877 | if (eventfp != d->log_file) { | |
878 | filep = d->log_file; | |
879 | ctx = d->log_ctx; | |
880 | d->log_ctx = eventfp ? | |
881 | eventfd_ctx_fileget(eventfp) : NULL; | |
882 | } else | |
883 | filep = eventfp; | |
884 | for (i = 0; i < d->nvqs; ++i) { | |
3ab2e420 AH |
885 | mutex_lock(&d->vqs[i]->mutex); |
886 | d->vqs[i]->log_ctx = d->log_ctx; | |
887 | mutex_unlock(&d->vqs[i]->mutex); | |
3a4d5c94 MT |
888 | } |
889 | if (ctx) | |
890 | eventfd_ctx_put(ctx); | |
891 | if (filep) | |
892 | fput(filep); | |
893 | break; | |
894 | default: | |
935cdee7 | 895 | r = -ENOIOCTLCMD; |
3a4d5c94 MT |
896 | break; |
897 | } | |
898 | done: | |
899 | return r; | |
900 | } | |
6ac1afbf | 901 | EXPORT_SYMBOL_GPL(vhost_dev_ioctl); |
3a4d5c94 MT |
902 | |
903 | static const struct vhost_memory_region *find_region(struct vhost_memory *mem, | |
904 | __u64 addr, __u32 len) | |
905 | { | |
906 | struct vhost_memory_region *reg; | |
907 | int i; | |
d47effe1 | 908 | |
3a4d5c94 MT |
909 | /* linear search is not brilliant, but we really have on the order of 6 |
910 | * regions in practice */ | |
911 | for (i = 0; i < mem->nregions; ++i) { | |
912 | reg = mem->regions + i; | |
913 | if (reg->guest_phys_addr <= addr && | |
914 | reg->guest_phys_addr + reg->memory_size - 1 >= addr) | |
915 | return reg; | |
916 | } | |
917 | return NULL; | |
918 | } | |
919 | ||
920 | /* TODO: This is really inefficient. We need something like get_user() | |
921 | * (instruction directly accesses the data, with an exception table entry | |
922 | * returning -EFAULT). See Documentation/x86/exception-tables.txt. | |
923 | */ | |
924 | static int set_bit_to_user(int nr, void __user *addr) | |
925 | { | |
926 | unsigned long log = (unsigned long)addr; | |
927 | struct page *page; | |
928 | void *base; | |
929 | int bit = nr + (log % PAGE_SIZE) * 8; | |
930 | int r; | |
d47effe1 | 931 | |
3a4d5c94 | 932 | r = get_user_pages_fast(log, 1, 1, &page); |
d6db3f5c | 933 | if (r < 0) |
3a4d5c94 | 934 | return r; |
d6db3f5c | 935 | BUG_ON(r != 1); |
c6daa7ff | 936 | base = kmap_atomic(page); |
3a4d5c94 | 937 | set_bit(bit, base); |
c6daa7ff | 938 | kunmap_atomic(base); |
3a4d5c94 MT |
939 | set_page_dirty_lock(page); |
940 | put_page(page); | |
941 | return 0; | |
942 | } | |
943 | ||
944 | static int log_write(void __user *log_base, | |
945 | u64 write_address, u64 write_length) | |
946 | { | |
28831ee6 | 947 | u64 write_page = write_address / VHOST_PAGE_SIZE; |
3a4d5c94 | 948 | int r; |
d47effe1 | 949 | |
3a4d5c94 MT |
950 | if (!write_length) |
951 | return 0; | |
3bf9be40 | 952 | write_length += write_address % VHOST_PAGE_SIZE; |
3a4d5c94 MT |
953 | for (;;) { |
954 | u64 base = (u64)(unsigned long)log_base; | |
28831ee6 MT |
955 | u64 log = base + write_page / 8; |
956 | int bit = write_page % 8; | |
3a4d5c94 MT |
957 | if ((u64)(unsigned long)log != log) |
958 | return -EFAULT; | |
959 | r = set_bit_to_user(bit, (void __user *)(unsigned long)log); | |
960 | if (r < 0) | |
961 | return r; | |
962 | if (write_length <= VHOST_PAGE_SIZE) | |
963 | break; | |
964 | write_length -= VHOST_PAGE_SIZE; | |
28831ee6 | 965 | write_page += 1; |
3a4d5c94 MT |
966 | } |
967 | return r; | |
968 | } | |
969 | ||
970 | int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, | |
971 | unsigned int log_num, u64 len) | |
972 | { | |
973 | int i, r; | |
974 | ||
975 | /* Make sure data written is seen before log. */ | |
5659338c | 976 | smp_wmb(); |
3a4d5c94 MT |
977 | for (i = 0; i < log_num; ++i) { |
978 | u64 l = min(log[i].len, len); | |
979 | r = log_write(vq->log_base, log[i].addr, l); | |
980 | if (r < 0) | |
981 | return r; | |
982 | len -= l; | |
5786aee8 MT |
983 | if (!len) { |
984 | if (vq->log_ctx) | |
985 | eventfd_signal(vq->log_ctx, 1); | |
3a4d5c94 | 986 | return 0; |
5786aee8 | 987 | } |
3a4d5c94 | 988 | } |
3a4d5c94 MT |
989 | /* Length written exceeds what we have stored. This is a bug. */ |
990 | BUG(); | |
991 | return 0; | |
992 | } | |
6ac1afbf | 993 | EXPORT_SYMBOL_GPL(vhost_log_write); |
3a4d5c94 | 994 | |
2723feaa JW |
995 | static int vhost_update_used_flags(struct vhost_virtqueue *vq) |
996 | { | |
997 | void __user *used; | |
b834226b | 998 | if (__put_user(vq->used_flags, &vq->used->flags) < 0) |
2723feaa JW |
999 | return -EFAULT; |
1000 | if (unlikely(vq->log_used)) { | |
1001 | /* Make sure the flag is seen before log. */ | |
1002 | smp_wmb(); | |
1003 | /* Log used flag write. */ | |
1004 | used = &vq->used->flags; | |
1005 | log_write(vq->log_base, vq->log_addr + | |
1006 | (used - (void __user *)vq->used), | |
1007 | sizeof vq->used->flags); | |
1008 | if (vq->log_ctx) | |
1009 | eventfd_signal(vq->log_ctx, 1); | |
1010 | } | |
1011 | return 0; | |
1012 | } | |
1013 | ||
1014 | static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event) | |
1015 | { | |
b834226b | 1016 | if (__put_user(vq->avail_idx, vhost_avail_event(vq))) |
2723feaa JW |
1017 | return -EFAULT; |
1018 | if (unlikely(vq->log_used)) { | |
1019 | void __user *used; | |
1020 | /* Make sure the event is seen before log. */ | |
1021 | smp_wmb(); | |
1022 | /* Log avail event write */ | |
1023 | used = vhost_avail_event(vq); | |
1024 | log_write(vq->log_base, vq->log_addr + | |
1025 | (used - (void __user *)vq->used), | |
1026 | sizeof *vhost_avail_event(vq)); | |
1027 | if (vq->log_ctx) | |
1028 | eventfd_signal(vq->log_ctx, 1); | |
1029 | } | |
1030 | return 0; | |
1031 | } | |
1032 | ||
1033 | int vhost_init_used(struct vhost_virtqueue *vq) | |
1034 | { | |
1035 | int r; | |
1036 | if (!vq->private_data) | |
1037 | return 0; | |
1038 | ||
1039 | r = vhost_update_used_flags(vq); | |
1040 | if (r) | |
1041 | return r; | |
1042 | vq->signalled_used_valid = false; | |
1043 | return get_user(vq->last_used_idx, &vq->used->idx); | |
1044 | } | |
6ac1afbf | 1045 | EXPORT_SYMBOL_GPL(vhost_init_used); |
2723feaa | 1046 | |
a8d3782f CH |
1047 | static int translate_desc(struct vhost_dev *dev, u64 addr, u32 len, |
1048 | struct iovec iov[], int iov_size) | |
3a4d5c94 MT |
1049 | { |
1050 | const struct vhost_memory_region *reg; | |
1051 | struct vhost_memory *mem; | |
1052 | struct iovec *_iov; | |
1053 | u64 s = 0; | |
1054 | int ret = 0; | |
1055 | ||
1056 | rcu_read_lock(); | |
1057 | ||
1058 | mem = rcu_dereference(dev->memory); | |
1059 | while ((u64)len > s) { | |
1060 | u64 size; | |
7b3384fc | 1061 | if (unlikely(ret >= iov_size)) { |
3a4d5c94 MT |
1062 | ret = -ENOBUFS; |
1063 | break; | |
1064 | } | |
1065 | reg = find_region(mem, addr, len); | |
7b3384fc | 1066 | if (unlikely(!reg)) { |
3a4d5c94 MT |
1067 | ret = -EFAULT; |
1068 | break; | |
1069 | } | |
1070 | _iov = iov + ret; | |
1071 | size = reg->memory_size - addr + reg->guest_phys_addr; | |
bd97120f | 1072 | _iov->iov_len = min((u64)len - s, size); |
a8d3782f | 1073 | _iov->iov_base = (void __user *)(unsigned long) |
3a4d5c94 MT |
1074 | (reg->userspace_addr + addr - reg->guest_phys_addr); |
1075 | s += size; | |
1076 | addr += size; | |
1077 | ++ret; | |
1078 | } | |
1079 | ||
1080 | rcu_read_unlock(); | |
1081 | return ret; | |
1082 | } | |
1083 | ||
1084 | /* Each buffer in the virtqueues is actually a chain of descriptors. This | |
1085 | * function returns the next descriptor in the chain, | |
1086 | * or -1U if we're at the end. */ | |
1087 | static unsigned next_desc(struct vring_desc *desc) | |
1088 | { | |
1089 | unsigned int next; | |
1090 | ||
1091 | /* If this descriptor says it doesn't chain, we're done. */ | |
1092 | if (!(desc->flags & VRING_DESC_F_NEXT)) | |
1093 | return -1U; | |
1094 | ||
1095 | /* Check they're not leading us off end of descriptors. */ | |
1096 | next = desc->next; | |
1097 | /* Make sure compiler knows to grab that: we don't want it changing! */ | |
1098 | /* We will use the result as an index in an array, so most | |
1099 | * architectures only need a compiler barrier here. */ | |
1100 | read_barrier_depends(); | |
1101 | ||
1102 | return next; | |
1103 | } | |
1104 | ||
7b3384fc MT |
1105 | static int get_indirect(struct vhost_dev *dev, struct vhost_virtqueue *vq, |
1106 | struct iovec iov[], unsigned int iov_size, | |
1107 | unsigned int *out_num, unsigned int *in_num, | |
1108 | struct vhost_log *log, unsigned int *log_num, | |
1109 | struct vring_desc *indirect) | |
3a4d5c94 MT |
1110 | { |
1111 | struct vring_desc desc; | |
1112 | unsigned int i = 0, count, found = 0; | |
1113 | int ret; | |
1114 | ||
1115 | /* Sanity check */ | |
7b3384fc | 1116 | if (unlikely(indirect->len % sizeof desc)) { |
3a4d5c94 MT |
1117 | vq_err(vq, "Invalid length in indirect descriptor: " |
1118 | "len 0x%llx not multiple of 0x%zx\n", | |
1119 | (unsigned long long)indirect->len, | |
1120 | sizeof desc); | |
1121 | return -EINVAL; | |
1122 | } | |
1123 | ||
1124 | ret = translate_desc(dev, indirect->addr, indirect->len, vq->indirect, | |
e0e9b406 | 1125 | UIO_MAXIOV); |
7b3384fc | 1126 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1127 | vq_err(vq, "Translation failure %d in indirect.\n", ret); |
1128 | return ret; | |
1129 | } | |
1130 | ||
1131 | /* We will use the result as an address to read from, so most | |
1132 | * architectures only need a compiler barrier here. */ | |
1133 | read_barrier_depends(); | |
1134 | ||
1135 | count = indirect->len / sizeof desc; | |
1136 | /* Buffers are chained via a 16 bit next field, so | |
1137 | * we can have at most 2^16 of these. */ | |
7b3384fc | 1138 | if (unlikely(count > USHRT_MAX + 1)) { |
3a4d5c94 MT |
1139 | vq_err(vq, "Indirect buffer length too big: %d\n", |
1140 | indirect->len); | |
1141 | return -E2BIG; | |
1142 | } | |
1143 | ||
1144 | do { | |
1145 | unsigned iov_count = *in_num + *out_num; | |
7b3384fc | 1146 | if (unlikely(++found > count)) { |
3a4d5c94 MT |
1147 | vq_err(vq, "Loop detected: last one at %u " |
1148 | "indirect size %u\n", | |
1149 | i, count); | |
1150 | return -EINVAL; | |
1151 | } | |
d47effe1 KK |
1152 | if (unlikely(memcpy_fromiovec((unsigned char *)&desc, |
1153 | vq->indirect, sizeof desc))) { | |
3a4d5c94 MT |
1154 | vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n", |
1155 | i, (size_t)indirect->addr + i * sizeof desc); | |
1156 | return -EINVAL; | |
1157 | } | |
7b3384fc | 1158 | if (unlikely(desc.flags & VRING_DESC_F_INDIRECT)) { |
3a4d5c94 MT |
1159 | vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n", |
1160 | i, (size_t)indirect->addr + i * sizeof desc); | |
1161 | return -EINVAL; | |
1162 | } | |
1163 | ||
1164 | ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, | |
1165 | iov_size - iov_count); | |
7b3384fc | 1166 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1167 | vq_err(vq, "Translation failure %d indirect idx %d\n", |
1168 | ret, i); | |
1169 | return ret; | |
1170 | } | |
1171 | /* If this is an input descriptor, increment that count. */ | |
1172 | if (desc.flags & VRING_DESC_F_WRITE) { | |
1173 | *in_num += ret; | |
1174 | if (unlikely(log)) { | |
1175 | log[*log_num].addr = desc.addr; | |
1176 | log[*log_num].len = desc.len; | |
1177 | ++*log_num; | |
1178 | } | |
1179 | } else { | |
1180 | /* If it's an output descriptor, they're all supposed | |
1181 | * to come before any input descriptors. */ | |
7b3384fc | 1182 | if (unlikely(*in_num)) { |
3a4d5c94 MT |
1183 | vq_err(vq, "Indirect descriptor " |
1184 | "has out after in: idx %d\n", i); | |
1185 | return -EINVAL; | |
1186 | } | |
1187 | *out_num += ret; | |
1188 | } | |
1189 | } while ((i = next_desc(&desc)) != -1); | |
1190 | return 0; | |
1191 | } | |
1192 | ||
1193 | /* This looks in the virtqueue and for the first available buffer, and converts | |
1194 | * it to an iovec for convenient access. Since descriptors consist of some | |
1195 | * number of output then some number of input descriptors, it's actually two | |
1196 | * iovecs, but we pack them into one and note how many of each there were. | |
1197 | * | |
d5675bd2 MT |
1198 | * This function returns the descriptor number found, or vq->num (which is |
1199 | * never a valid descriptor number) if none was found. A negative code is | |
1200 | * returned on error. */ | |
1201 | int vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq, | |
1202 | struct iovec iov[], unsigned int iov_size, | |
1203 | unsigned int *out_num, unsigned int *in_num, | |
1204 | struct vhost_log *log, unsigned int *log_num) | |
3a4d5c94 MT |
1205 | { |
1206 | struct vring_desc desc; | |
1207 | unsigned int i, head, found = 0; | |
1208 | u16 last_avail_idx; | |
1209 | int ret; | |
1210 | ||
1211 | /* Check it isn't doing very strange things with descriptor numbers. */ | |
1212 | last_avail_idx = vq->last_avail_idx; | |
8b7347aa | 1213 | if (unlikely(__get_user(vq->avail_idx, &vq->avail->idx))) { |
3a4d5c94 MT |
1214 | vq_err(vq, "Failed to access avail idx at %p\n", |
1215 | &vq->avail->idx); | |
d5675bd2 | 1216 | return -EFAULT; |
3a4d5c94 MT |
1217 | } |
1218 | ||
7b3384fc | 1219 | if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) { |
3a4d5c94 MT |
1220 | vq_err(vq, "Guest moved used index from %u to %u", |
1221 | last_avail_idx, vq->avail_idx); | |
d5675bd2 | 1222 | return -EFAULT; |
3a4d5c94 MT |
1223 | } |
1224 | ||
1225 | /* If there's nothing new since last we looked, return invalid. */ | |
1226 | if (vq->avail_idx == last_avail_idx) | |
1227 | return vq->num; | |
1228 | ||
1229 | /* Only get avail ring entries after they have been exposed by guest. */ | |
5659338c | 1230 | smp_rmb(); |
3a4d5c94 MT |
1231 | |
1232 | /* Grab the next descriptor number they're advertising, and increment | |
1233 | * the index we've seen. */ | |
8b7347aa MT |
1234 | if (unlikely(__get_user(head, |
1235 | &vq->avail->ring[last_avail_idx % vq->num]))) { | |
3a4d5c94 MT |
1236 | vq_err(vq, "Failed to read head: idx %d address %p\n", |
1237 | last_avail_idx, | |
1238 | &vq->avail->ring[last_avail_idx % vq->num]); | |
d5675bd2 | 1239 | return -EFAULT; |
3a4d5c94 MT |
1240 | } |
1241 | ||
1242 | /* If their number is silly, that's an error. */ | |
7b3384fc | 1243 | if (unlikely(head >= vq->num)) { |
3a4d5c94 MT |
1244 | vq_err(vq, "Guest says index %u > %u is available", |
1245 | head, vq->num); | |
d5675bd2 | 1246 | return -EINVAL; |
3a4d5c94 MT |
1247 | } |
1248 | ||
1249 | /* When we start there are none of either input nor output. */ | |
1250 | *out_num = *in_num = 0; | |
1251 | if (unlikely(log)) | |
1252 | *log_num = 0; | |
1253 | ||
1254 | i = head; | |
1255 | do { | |
1256 | unsigned iov_count = *in_num + *out_num; | |
7b3384fc | 1257 | if (unlikely(i >= vq->num)) { |
3a4d5c94 MT |
1258 | vq_err(vq, "Desc index is %u > %u, head = %u", |
1259 | i, vq->num, head); | |
d5675bd2 | 1260 | return -EINVAL; |
3a4d5c94 | 1261 | } |
7b3384fc | 1262 | if (unlikely(++found > vq->num)) { |
3a4d5c94 MT |
1263 | vq_err(vq, "Loop detected: last one at %u " |
1264 | "vq size %u head %u\n", | |
1265 | i, vq->num, head); | |
d5675bd2 | 1266 | return -EINVAL; |
3a4d5c94 | 1267 | } |
fcc042a2 | 1268 | ret = __copy_from_user(&desc, vq->desc + i, sizeof desc); |
7b3384fc | 1269 | if (unlikely(ret)) { |
3a4d5c94 MT |
1270 | vq_err(vq, "Failed to get descriptor: idx %d addr %p\n", |
1271 | i, vq->desc + i); | |
d5675bd2 | 1272 | return -EFAULT; |
3a4d5c94 MT |
1273 | } |
1274 | if (desc.flags & VRING_DESC_F_INDIRECT) { | |
1275 | ret = get_indirect(dev, vq, iov, iov_size, | |
1276 | out_num, in_num, | |
1277 | log, log_num, &desc); | |
7b3384fc | 1278 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1279 | vq_err(vq, "Failure detected " |
1280 | "in indirect descriptor at idx %d\n", i); | |
d5675bd2 | 1281 | return ret; |
3a4d5c94 MT |
1282 | } |
1283 | continue; | |
1284 | } | |
1285 | ||
1286 | ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, | |
1287 | iov_size - iov_count); | |
7b3384fc | 1288 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1289 | vq_err(vq, "Translation failure %d descriptor idx %d\n", |
1290 | ret, i); | |
d5675bd2 | 1291 | return ret; |
3a4d5c94 MT |
1292 | } |
1293 | if (desc.flags & VRING_DESC_F_WRITE) { | |
1294 | /* If this is an input descriptor, | |
1295 | * increment that count. */ | |
1296 | *in_num += ret; | |
1297 | if (unlikely(log)) { | |
1298 | log[*log_num].addr = desc.addr; | |
1299 | log[*log_num].len = desc.len; | |
1300 | ++*log_num; | |
1301 | } | |
1302 | } else { | |
1303 | /* If it's an output descriptor, they're all supposed | |
1304 | * to come before any input descriptors. */ | |
7b3384fc | 1305 | if (unlikely(*in_num)) { |
3a4d5c94 MT |
1306 | vq_err(vq, "Descriptor has out after in: " |
1307 | "idx %d\n", i); | |
d5675bd2 | 1308 | return -EINVAL; |
3a4d5c94 MT |
1309 | } |
1310 | *out_num += ret; | |
1311 | } | |
1312 | } while ((i = next_desc(&desc)) != -1); | |
1313 | ||
1314 | /* On success, increment avail index. */ | |
1315 | vq->last_avail_idx++; | |
8ea8cf89 MT |
1316 | |
1317 | /* Assume notifications from guest are disabled at this point, | |
1318 | * if they aren't we would need to update avail_event index. */ | |
1319 | BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY)); | |
3a4d5c94 MT |
1320 | return head; |
1321 | } | |
6ac1afbf | 1322 | EXPORT_SYMBOL_GPL(vhost_get_vq_desc); |
3a4d5c94 MT |
1323 | |
1324 | /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */ | |
8dd014ad | 1325 | void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n) |
3a4d5c94 | 1326 | { |
8dd014ad | 1327 | vq->last_avail_idx -= n; |
3a4d5c94 | 1328 | } |
6ac1afbf | 1329 | EXPORT_SYMBOL_GPL(vhost_discard_vq_desc); |
3a4d5c94 MT |
1330 | |
1331 | /* After we've used one of their buffers, we tell them about it. We'll then | |
1332 | * want to notify the guest, using eventfd. */ | |
1333 | int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len) | |
1334 | { | |
a8d3782f | 1335 | struct vring_used_elem __user *used; |
3a4d5c94 MT |
1336 | |
1337 | /* The virtqueue contains a ring of used buffers. Get a pointer to the | |
1338 | * next entry in that used ring. */ | |
1339 | used = &vq->used->ring[vq->last_used_idx % vq->num]; | |
8b7347aa | 1340 | if (__put_user(head, &used->id)) { |
3a4d5c94 MT |
1341 | vq_err(vq, "Failed to write used id"); |
1342 | return -EFAULT; | |
1343 | } | |
8b7347aa | 1344 | if (__put_user(len, &used->len)) { |
3a4d5c94 MT |
1345 | vq_err(vq, "Failed to write used len"); |
1346 | return -EFAULT; | |
1347 | } | |
1348 | /* Make sure buffer is written before we update index. */ | |
5659338c | 1349 | smp_wmb(); |
8b7347aa | 1350 | if (__put_user(vq->last_used_idx + 1, &vq->used->idx)) { |
3a4d5c94 MT |
1351 | vq_err(vq, "Failed to increment used idx"); |
1352 | return -EFAULT; | |
1353 | } | |
1354 | if (unlikely(vq->log_used)) { | |
1355 | /* Make sure data is seen before log. */ | |
5659338c | 1356 | smp_wmb(); |
86e9424d MT |
1357 | /* Log used ring entry write. */ |
1358 | log_write(vq->log_base, | |
a8d3782f CH |
1359 | vq->log_addr + |
1360 | ((void __user *)used - (void __user *)vq->used), | |
86e9424d MT |
1361 | sizeof *used); |
1362 | /* Log used index update. */ | |
1363 | log_write(vq->log_base, | |
1364 | vq->log_addr + offsetof(struct vring_used, idx), | |
1365 | sizeof vq->used->idx); | |
3a4d5c94 MT |
1366 | if (vq->log_ctx) |
1367 | eventfd_signal(vq->log_ctx, 1); | |
1368 | } | |
1369 | vq->last_used_idx++; | |
8ea8cf89 MT |
1370 | /* If the driver never bothers to signal in a very long while, |
1371 | * used index might wrap around. If that happens, invalidate | |
1372 | * signalled_used index we stored. TODO: make sure driver | |
1373 | * signals at least once in 2^16 and remove this. */ | |
1374 | if (unlikely(vq->last_used_idx == vq->signalled_used)) | |
1375 | vq->signalled_used_valid = false; | |
3a4d5c94 MT |
1376 | return 0; |
1377 | } | |
6ac1afbf | 1378 | EXPORT_SYMBOL_GPL(vhost_add_used); |
3a4d5c94 | 1379 | |
8dd014ad DS |
1380 | static int __vhost_add_used_n(struct vhost_virtqueue *vq, |
1381 | struct vring_used_elem *heads, | |
1382 | unsigned count) | |
1383 | { | |
1384 | struct vring_used_elem __user *used; | |
8ea8cf89 | 1385 | u16 old, new; |
8dd014ad DS |
1386 | int start; |
1387 | ||
1388 | start = vq->last_used_idx % vq->num; | |
1389 | used = vq->used->ring + start; | |
dfe5ac5b | 1390 | if (__copy_to_user(used, heads, count * sizeof *used)) { |
8dd014ad DS |
1391 | vq_err(vq, "Failed to write used"); |
1392 | return -EFAULT; | |
1393 | } | |
1394 | if (unlikely(vq->log_used)) { | |
1395 | /* Make sure data is seen before log. */ | |
1396 | smp_wmb(); | |
1397 | /* Log used ring entry write. */ | |
1398 | log_write(vq->log_base, | |
1399 | vq->log_addr + | |
1400 | ((void __user *)used - (void __user *)vq->used), | |
1401 | count * sizeof *used); | |
1402 | } | |
8ea8cf89 MT |
1403 | old = vq->last_used_idx; |
1404 | new = (vq->last_used_idx += count); | |
1405 | /* If the driver never bothers to signal in a very long while, | |
1406 | * used index might wrap around. If that happens, invalidate | |
1407 | * signalled_used index we stored. TODO: make sure driver | |
1408 | * signals at least once in 2^16 and remove this. */ | |
1409 | if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old))) | |
1410 | vq->signalled_used_valid = false; | |
8dd014ad DS |
1411 | return 0; |
1412 | } | |
1413 | ||
1414 | /* After we've used one of their buffers, we tell them about it. We'll then | |
1415 | * want to notify the guest, using eventfd. */ | |
1416 | int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads, | |
1417 | unsigned count) | |
1418 | { | |
1419 | int start, n, r; | |
1420 | ||
1421 | start = vq->last_used_idx % vq->num; | |
1422 | n = vq->num - start; | |
1423 | if (n < count) { | |
1424 | r = __vhost_add_used_n(vq, heads, n); | |
1425 | if (r < 0) | |
1426 | return r; | |
1427 | heads += n; | |
1428 | count -= n; | |
1429 | } | |
1430 | r = __vhost_add_used_n(vq, heads, count); | |
1431 | ||
1432 | /* Make sure buffer is written before we update index. */ | |
1433 | smp_wmb(); | |
1434 | if (put_user(vq->last_used_idx, &vq->used->idx)) { | |
1435 | vq_err(vq, "Failed to increment used idx"); | |
1436 | return -EFAULT; | |
1437 | } | |
1438 | if (unlikely(vq->log_used)) { | |
1439 | /* Log used index update. */ | |
1440 | log_write(vq->log_base, | |
1441 | vq->log_addr + offsetof(struct vring_used, idx), | |
1442 | sizeof vq->used->idx); | |
1443 | if (vq->log_ctx) | |
1444 | eventfd_signal(vq->log_ctx, 1); | |
1445 | } | |
1446 | return r; | |
1447 | } | |
6ac1afbf | 1448 | EXPORT_SYMBOL_GPL(vhost_add_used_n); |
8dd014ad | 1449 | |
8ea8cf89 | 1450 | static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
3a4d5c94 | 1451 | { |
8ea8cf89 MT |
1452 | __u16 old, new, event; |
1453 | bool v; | |
0d499356 MT |
1454 | /* Flush out used index updates. This is paired |
1455 | * with the barrier that the Guest executes when enabling | |
1456 | * interrupts. */ | |
1457 | smp_mb(); | |
1458 | ||
8ea8cf89 MT |
1459 | if (vhost_has_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY) && |
1460 | unlikely(vq->avail_idx == vq->last_avail_idx)) | |
1461 | return true; | |
1462 | ||
1463 | if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { | |
1464 | __u16 flags; | |
1465 | if (__get_user(flags, &vq->avail->flags)) { | |
1466 | vq_err(vq, "Failed to get flags"); | |
1467 | return true; | |
1468 | } | |
1469 | return !(flags & VRING_AVAIL_F_NO_INTERRUPT); | |
3a4d5c94 | 1470 | } |
8ea8cf89 MT |
1471 | old = vq->signalled_used; |
1472 | v = vq->signalled_used_valid; | |
1473 | new = vq->signalled_used = vq->last_used_idx; | |
1474 | vq->signalled_used_valid = true; | |
3a4d5c94 | 1475 | |
8ea8cf89 MT |
1476 | if (unlikely(!v)) |
1477 | return true; | |
3a4d5c94 | 1478 | |
8ea8cf89 MT |
1479 | if (get_user(event, vhost_used_event(vq))) { |
1480 | vq_err(vq, "Failed to get used event idx"); | |
1481 | return true; | |
1482 | } | |
1483 | return vring_need_event(event, new, old); | |
1484 | } | |
1485 | ||
1486 | /* This actually signals the guest, using eventfd. */ | |
1487 | void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq) | |
1488 | { | |
3a4d5c94 | 1489 | /* Signal the Guest tell them we used something up. */ |
8ea8cf89 | 1490 | if (vq->call_ctx && vhost_notify(dev, vq)) |
3a4d5c94 MT |
1491 | eventfd_signal(vq->call_ctx, 1); |
1492 | } | |
6ac1afbf | 1493 | EXPORT_SYMBOL_GPL(vhost_signal); |
3a4d5c94 MT |
1494 | |
1495 | /* And here's the combo meal deal. Supersize me! */ | |
1496 | void vhost_add_used_and_signal(struct vhost_dev *dev, | |
1497 | struct vhost_virtqueue *vq, | |
1498 | unsigned int head, int len) | |
1499 | { | |
1500 | vhost_add_used(vq, head, len); | |
1501 | vhost_signal(dev, vq); | |
1502 | } | |
6ac1afbf | 1503 | EXPORT_SYMBOL_GPL(vhost_add_used_and_signal); |
3a4d5c94 | 1504 | |
8dd014ad DS |
1505 | /* multi-buffer version of vhost_add_used_and_signal */ |
1506 | void vhost_add_used_and_signal_n(struct vhost_dev *dev, | |
1507 | struct vhost_virtqueue *vq, | |
1508 | struct vring_used_elem *heads, unsigned count) | |
1509 | { | |
1510 | vhost_add_used_n(vq, heads, count); | |
1511 | vhost_signal(dev, vq); | |
1512 | } | |
6ac1afbf | 1513 | EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n); |
8dd014ad | 1514 | |
3a4d5c94 | 1515 | /* OK, now we need to know about added descriptors. */ |
8ea8cf89 | 1516 | bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
3a4d5c94 MT |
1517 | { |
1518 | u16 avail_idx; | |
1519 | int r; | |
d47effe1 | 1520 | |
3a4d5c94 MT |
1521 | if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY)) |
1522 | return false; | |
1523 | vq->used_flags &= ~VRING_USED_F_NO_NOTIFY; | |
8ea8cf89 | 1524 | if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { |
2723feaa | 1525 | r = vhost_update_used_flags(vq); |
8ea8cf89 MT |
1526 | if (r) { |
1527 | vq_err(vq, "Failed to enable notification at %p: %d\n", | |
1528 | &vq->used->flags, r); | |
1529 | return false; | |
1530 | } | |
1531 | } else { | |
2723feaa | 1532 | r = vhost_update_avail_event(vq, vq->avail_idx); |
8ea8cf89 MT |
1533 | if (r) { |
1534 | vq_err(vq, "Failed to update avail event index at %p: %d\n", | |
1535 | vhost_avail_event(vq), r); | |
1536 | return false; | |
1537 | } | |
1538 | } | |
3a4d5c94 MT |
1539 | /* They could have slipped one in as we were doing that: make |
1540 | * sure it's written, then check again. */ | |
5659338c | 1541 | smp_mb(); |
8b7347aa | 1542 | r = __get_user(avail_idx, &vq->avail->idx); |
3a4d5c94 MT |
1543 | if (r) { |
1544 | vq_err(vq, "Failed to check avail idx at %p: %d\n", | |
1545 | &vq->avail->idx, r); | |
1546 | return false; | |
1547 | } | |
1548 | ||
8dd014ad | 1549 | return avail_idx != vq->avail_idx; |
3a4d5c94 | 1550 | } |
6ac1afbf | 1551 | EXPORT_SYMBOL_GPL(vhost_enable_notify); |
3a4d5c94 MT |
1552 | |
1553 | /* We don't need to be notified again. */ | |
8ea8cf89 | 1554 | void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
3a4d5c94 MT |
1555 | { |
1556 | int r; | |
d47effe1 | 1557 | |
3a4d5c94 MT |
1558 | if (vq->used_flags & VRING_USED_F_NO_NOTIFY) |
1559 | return; | |
1560 | vq->used_flags |= VRING_USED_F_NO_NOTIFY; | |
8ea8cf89 | 1561 | if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { |
2723feaa | 1562 | r = vhost_update_used_flags(vq); |
8ea8cf89 MT |
1563 | if (r) |
1564 | vq_err(vq, "Failed to enable notification at %p: %d\n", | |
1565 | &vq->used->flags, r); | |
1566 | } | |
3a4d5c94 | 1567 | } |
6ac1afbf AH |
1568 | EXPORT_SYMBOL_GPL(vhost_disable_notify); |
1569 | ||
1570 | static int __init vhost_init(void) | |
1571 | { | |
1572 | return 0; | |
1573 | } | |
1574 | ||
1575 | static void __exit vhost_exit(void) | |
1576 | { | |
1577 | } | |
1578 | ||
1579 | module_init(vhost_init); | |
1580 | module_exit(vhost_exit); | |
1581 | ||
1582 | MODULE_VERSION("0.0.1"); | |
1583 | MODULE_LICENSE("GPL v2"); | |
1584 | MODULE_AUTHOR("Michael S. Tsirkin"); | |
1585 | MODULE_DESCRIPTION("Host kernel accelerator for virtio"); |