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