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 MT |
28 | |
29 | #include <linux/net.h> | |
30 | #include <linux/if_packet.h> | |
31 | #include <linux/if_arp.h> | |
32 | ||
3a4d5c94 MT |
33 | #include "vhost.h" |
34 | ||
35 | enum { | |
36 | VHOST_MEMORY_MAX_NREGIONS = 64, | |
37 | VHOST_MEMORY_F_LOG = 0x1, | |
38 | }; | |
39 | ||
bab632d6 MT |
40 | static unsigned vhost_zcopy_mask __read_mostly; |
41 | ||
8ea8cf89 MT |
42 | #define vhost_used_event(vq) ((u16 __user *)&vq->avail->ring[vq->num]) |
43 | #define vhost_avail_event(vq) ((u16 __user *)&vq->used->ring[vq->num]) | |
44 | ||
3a4d5c94 MT |
45 | static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh, |
46 | poll_table *pt) | |
47 | { | |
48 | struct vhost_poll *poll; | |
3a4d5c94 | 49 | |
d47effe1 | 50 | poll = container_of(pt, struct vhost_poll, table); |
3a4d5c94 MT |
51 | poll->wqh = wqh; |
52 | add_wait_queue(wqh, &poll->wait); | |
53 | } | |
54 | ||
55 | static int vhost_poll_wakeup(wait_queue_t *wait, unsigned mode, int sync, | |
56 | void *key) | |
57 | { | |
c23f3445 TH |
58 | struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait); |
59 | ||
3a4d5c94 MT |
60 | if (!((unsigned long)key & poll->mask)) |
61 | return 0; | |
62 | ||
c23f3445 | 63 | vhost_poll_queue(poll); |
3a4d5c94 MT |
64 | return 0; |
65 | } | |
66 | ||
87d6a412 MT |
67 | static void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn) |
68 | { | |
69 | INIT_LIST_HEAD(&work->node); | |
70 | work->fn = fn; | |
71 | init_waitqueue_head(&work->done); | |
72 | work->flushing = 0; | |
73 | work->queue_seq = work->done_seq = 0; | |
74 | } | |
75 | ||
3a4d5c94 | 76 | /* Init poll structure */ |
c23f3445 TH |
77 | void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, |
78 | unsigned long mask, struct vhost_dev *dev) | |
3a4d5c94 | 79 | { |
3a4d5c94 MT |
80 | init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup); |
81 | init_poll_funcptr(&poll->table, vhost_poll_func); | |
82 | poll->mask = mask; | |
c23f3445 TH |
83 | poll->dev = dev; |
84 | ||
87d6a412 | 85 | vhost_work_init(&poll->work, fn); |
3a4d5c94 MT |
86 | } |
87 | ||
88 | /* Start polling a file. We add ourselves to file's wait queue. The caller must | |
89 | * keep a reference to a file until after vhost_poll_stop is called. */ | |
90 | void vhost_poll_start(struct vhost_poll *poll, struct file *file) | |
91 | { | |
92 | unsigned long mask; | |
d47effe1 | 93 | |
3a4d5c94 MT |
94 | mask = file->f_op->poll(file, &poll->table); |
95 | if (mask) | |
96 | vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask); | |
97 | } | |
98 | ||
99 | /* Stop polling a file. After this function returns, it becomes safe to drop the | |
100 | * file reference. You must also flush afterwards. */ | |
101 | void vhost_poll_stop(struct vhost_poll *poll) | |
102 | { | |
103 | remove_wait_queue(poll->wqh, &poll->wait); | |
104 | } | |
105 | ||
0174b0c3 MT |
106 | static bool vhost_work_seq_done(struct vhost_dev *dev, struct vhost_work *work, |
107 | unsigned seq) | |
108 | { | |
109 | int left; | |
d47effe1 | 110 | |
0174b0c3 MT |
111 | spin_lock_irq(&dev->work_lock); |
112 | left = seq - work->done_seq; | |
113 | spin_unlock_irq(&dev->work_lock); | |
114 | return left <= 0; | |
115 | } | |
116 | ||
87d6a412 | 117 | static void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work) |
3a4d5c94 | 118 | { |
c23f3445 | 119 | unsigned seq; |
c23f3445 TH |
120 | int flushing; |
121 | ||
87d6a412 | 122 | spin_lock_irq(&dev->work_lock); |
c23f3445 TH |
123 | seq = work->queue_seq; |
124 | work->flushing++; | |
87d6a412 | 125 | spin_unlock_irq(&dev->work_lock); |
0174b0c3 | 126 | wait_event(work->done, vhost_work_seq_done(dev, work, seq)); |
87d6a412 | 127 | spin_lock_irq(&dev->work_lock); |
c23f3445 | 128 | flushing = --work->flushing; |
87d6a412 | 129 | spin_unlock_irq(&dev->work_lock); |
c23f3445 | 130 | BUG_ON(flushing < 0); |
3a4d5c94 MT |
131 | } |
132 | ||
87d6a412 MT |
133 | /* Flush any work that has been scheduled. When calling this, don't hold any |
134 | * locks that are also used by the callback. */ | |
135 | void vhost_poll_flush(struct vhost_poll *poll) | |
136 | { | |
137 | vhost_work_flush(poll->dev, &poll->work); | |
138 | } | |
139 | ||
140 | static inline void vhost_work_queue(struct vhost_dev *dev, | |
141 | struct vhost_work *work) | |
3a4d5c94 | 142 | { |
c23f3445 TH |
143 | unsigned long flags; |
144 | ||
145 | spin_lock_irqsave(&dev->work_lock, flags); | |
146 | if (list_empty(&work->node)) { | |
147 | list_add_tail(&work->node, &dev->work_list); | |
148 | work->queue_seq++; | |
149 | wake_up_process(dev->worker); | |
150 | } | |
151 | spin_unlock_irqrestore(&dev->work_lock, flags); | |
3a4d5c94 MT |
152 | } |
153 | ||
87d6a412 MT |
154 | void vhost_poll_queue(struct vhost_poll *poll) |
155 | { | |
156 | vhost_work_queue(poll->dev, &poll->work); | |
157 | } | |
158 | ||
3a4d5c94 MT |
159 | static void vhost_vq_reset(struct vhost_dev *dev, |
160 | struct vhost_virtqueue *vq) | |
161 | { | |
162 | vq->num = 1; | |
163 | vq->desc = NULL; | |
164 | vq->avail = NULL; | |
165 | vq->used = NULL; | |
166 | vq->last_avail_idx = 0; | |
167 | vq->avail_idx = 0; | |
168 | vq->last_used_idx = 0; | |
8ea8cf89 MT |
169 | vq->signalled_used = 0; |
170 | vq->signalled_used_valid = false; | |
3a4d5c94 | 171 | vq->used_flags = 0; |
3a4d5c94 MT |
172 | vq->log_used = false; |
173 | vq->log_addr = -1ull; | |
8dd014ad DS |
174 | vq->vhost_hlen = 0; |
175 | vq->sock_hlen = 0; | |
3a4d5c94 MT |
176 | vq->private_data = NULL; |
177 | vq->log_base = NULL; | |
178 | vq->error_ctx = NULL; | |
179 | vq->error = NULL; | |
180 | vq->kick = NULL; | |
181 | vq->call_ctx = NULL; | |
182 | vq->call = NULL; | |
73a99f08 | 183 | vq->log_ctx = NULL; |
bab632d6 MT |
184 | vq->upend_idx = 0; |
185 | vq->done_idx = 0; | |
186 | vq->ubufs = NULL; | |
3a4d5c94 MT |
187 | } |
188 | ||
c23f3445 TH |
189 | static int vhost_worker(void *data) |
190 | { | |
191 | struct vhost_dev *dev = data; | |
192 | struct vhost_work *work = NULL; | |
193 | unsigned uninitialized_var(seq); | |
d7ffde35 | 194 | mm_segment_t oldfs = get_fs(); |
c23f3445 | 195 | |
d7ffde35 | 196 | set_fs(USER_DS); |
64e1c807 MT |
197 | use_mm(dev->mm); |
198 | ||
c23f3445 TH |
199 | for (;;) { |
200 | /* mb paired w/ kthread_stop */ | |
201 | set_current_state(TASK_INTERRUPTIBLE); | |
202 | ||
203 | spin_lock_irq(&dev->work_lock); | |
204 | if (work) { | |
205 | work->done_seq = seq; | |
206 | if (work->flushing) | |
207 | wake_up_all(&work->done); | |
208 | } | |
209 | ||
210 | if (kthread_should_stop()) { | |
211 | spin_unlock_irq(&dev->work_lock); | |
212 | __set_current_state(TASK_RUNNING); | |
64e1c807 | 213 | break; |
c23f3445 TH |
214 | } |
215 | if (!list_empty(&dev->work_list)) { | |
216 | work = list_first_entry(&dev->work_list, | |
217 | struct vhost_work, node); | |
218 | list_del_init(&work->node); | |
219 | seq = work->queue_seq; | |
220 | } else | |
221 | work = NULL; | |
222 | spin_unlock_irq(&dev->work_lock); | |
223 | ||
224 | if (work) { | |
225 | __set_current_state(TASK_RUNNING); | |
226 | work->fn(work); | |
d550dda1 NHE |
227 | if (need_resched()) |
228 | schedule(); | |
c23f3445 TH |
229 | } else |
230 | schedule(); | |
231 | ||
232 | } | |
64e1c807 | 233 | unuse_mm(dev->mm); |
d7ffde35 | 234 | set_fs(oldfs); |
64e1c807 | 235 | return 0; |
c23f3445 TH |
236 | } |
237 | ||
bab632d6 MT |
238 | static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq) |
239 | { | |
240 | kfree(vq->indirect); | |
241 | vq->indirect = NULL; | |
242 | kfree(vq->log); | |
243 | vq->log = NULL; | |
244 | kfree(vq->heads); | |
245 | vq->heads = NULL; | |
246 | kfree(vq->ubuf_info); | |
247 | vq->ubuf_info = NULL; | |
248 | } | |
249 | ||
250 | void vhost_enable_zcopy(int vq) | |
251 | { | |
252 | vhost_zcopy_mask |= 0x1 << vq; | |
253 | } | |
254 | ||
e0e9b406 JW |
255 | /* Helper to allocate iovec buffers for all vqs. */ |
256 | static long vhost_dev_alloc_iovecs(struct vhost_dev *dev) | |
257 | { | |
258 | int i; | |
bab632d6 | 259 | bool zcopy; |
d47effe1 | 260 | |
e0e9b406 JW |
261 | for (i = 0; i < dev->nvqs; ++i) { |
262 | dev->vqs[i].indirect = kmalloc(sizeof *dev->vqs[i].indirect * | |
263 | UIO_MAXIOV, GFP_KERNEL); | |
264 | dev->vqs[i].log = kmalloc(sizeof *dev->vqs[i].log * UIO_MAXIOV, | |
265 | GFP_KERNEL); | |
266 | dev->vqs[i].heads = kmalloc(sizeof *dev->vqs[i].heads * | |
267 | UIO_MAXIOV, GFP_KERNEL); | |
bab632d6 MT |
268 | zcopy = vhost_zcopy_mask & (0x1 << i); |
269 | if (zcopy) | |
270 | dev->vqs[i].ubuf_info = | |
271 | kmalloc(sizeof *dev->vqs[i].ubuf_info * | |
272 | UIO_MAXIOV, GFP_KERNEL); | |
e0e9b406 | 273 | if (!dev->vqs[i].indirect || !dev->vqs[i].log || |
bab632d6 MT |
274 | !dev->vqs[i].heads || |
275 | (zcopy && !dev->vqs[i].ubuf_info)) | |
e0e9b406 JW |
276 | goto err_nomem; |
277 | } | |
278 | return 0; | |
d47effe1 | 279 | |
e0e9b406 | 280 | err_nomem: |
bab632d6 MT |
281 | for (; i >= 0; --i) |
282 | vhost_vq_free_iovecs(&dev->vqs[i]); | |
e0e9b406 JW |
283 | return -ENOMEM; |
284 | } | |
285 | ||
286 | static void vhost_dev_free_iovecs(struct vhost_dev *dev) | |
287 | { | |
288 | int i; | |
d47effe1 | 289 | |
bab632d6 MT |
290 | for (i = 0; i < dev->nvqs; ++i) |
291 | vhost_vq_free_iovecs(&dev->vqs[i]); | |
e0e9b406 JW |
292 | } |
293 | ||
3a4d5c94 MT |
294 | long vhost_dev_init(struct vhost_dev *dev, |
295 | struct vhost_virtqueue *vqs, int nvqs) | |
296 | { | |
297 | int i; | |
c23f3445 | 298 | |
3a4d5c94 MT |
299 | dev->vqs = vqs; |
300 | dev->nvqs = nvqs; | |
301 | mutex_init(&dev->mutex); | |
302 | dev->log_ctx = NULL; | |
303 | dev->log_file = NULL; | |
304 | dev->memory = NULL; | |
305 | dev->mm = NULL; | |
c23f3445 TH |
306 | spin_lock_init(&dev->work_lock); |
307 | INIT_LIST_HEAD(&dev->work_list); | |
308 | dev->worker = NULL; | |
3a4d5c94 MT |
309 | |
310 | for (i = 0; i < dev->nvqs; ++i) { | |
e0e9b406 JW |
311 | dev->vqs[i].log = NULL; |
312 | dev->vqs[i].indirect = NULL; | |
313 | dev->vqs[i].heads = NULL; | |
bab632d6 | 314 | dev->vqs[i].ubuf_info = NULL; |
3a4d5c94 MT |
315 | dev->vqs[i].dev = dev; |
316 | mutex_init(&dev->vqs[i].mutex); | |
317 | vhost_vq_reset(dev, dev->vqs + i); | |
318 | if (dev->vqs[i].handle_kick) | |
319 | vhost_poll_init(&dev->vqs[i].poll, | |
c23f3445 | 320 | dev->vqs[i].handle_kick, POLLIN, dev); |
3a4d5c94 | 321 | } |
c23f3445 | 322 | |
3a4d5c94 MT |
323 | return 0; |
324 | } | |
325 | ||
326 | /* Caller should have device mutex */ | |
327 | long vhost_dev_check_owner(struct vhost_dev *dev) | |
328 | { | |
329 | /* Are you the owner? If not, I don't think you mean to do that */ | |
330 | return dev->mm == current->mm ? 0 : -EPERM; | |
331 | } | |
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 | ||
3a4d5c94 MT |
358 | /* Caller should have device mutex */ |
359 | static long vhost_dev_set_owner(struct vhost_dev *dev) | |
360 | { | |
c23f3445 TH |
361 | struct task_struct *worker; |
362 | int err; | |
d47effe1 | 363 | |
3a4d5c94 | 364 | /* Is there an owner already? */ |
c23f3445 TH |
365 | if (dev->mm) { |
366 | err = -EBUSY; | |
367 | goto err_mm; | |
368 | } | |
d47effe1 | 369 | |
3a4d5c94 MT |
370 | /* No owner, become one */ |
371 | dev->mm = get_task_mm(current); | |
c23f3445 TH |
372 | worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid); |
373 | if (IS_ERR(worker)) { | |
374 | err = PTR_ERR(worker); | |
375 | goto err_worker; | |
376 | } | |
377 | ||
378 | dev->worker = worker; | |
87d6a412 MT |
379 | wake_up_process(worker); /* avoid contributing to loadavg */ |
380 | ||
381 | err = vhost_attach_cgroups(dev); | |
9e3d1957 MT |
382 | if (err) |
383 | goto err_cgroup; | |
c23f3445 | 384 | |
e0e9b406 JW |
385 | err = vhost_dev_alloc_iovecs(dev); |
386 | if (err) | |
387 | goto err_cgroup; | |
388 | ||
3a4d5c94 | 389 | return 0; |
9e3d1957 MT |
390 | err_cgroup: |
391 | kthread_stop(worker); | |
615cc221 | 392 | dev->worker = NULL; |
c23f3445 TH |
393 | err_worker: |
394 | if (dev->mm) | |
395 | mmput(dev->mm); | |
396 | dev->mm = NULL; | |
397 | err_mm: | |
398 | return err; | |
3a4d5c94 MT |
399 | } |
400 | ||
401 | /* Caller should have device mutex */ | |
402 | long vhost_dev_reset_owner(struct vhost_dev *dev) | |
403 | { | |
404 | struct vhost_memory *memory; | |
405 | ||
406 | /* Restore memory to default empty mapping. */ | |
407 | memory = kmalloc(offsetof(struct vhost_memory, regions), GFP_KERNEL); | |
408 | if (!memory) | |
409 | return -ENOMEM; | |
410 | ||
ea5d4046 | 411 | vhost_dev_cleanup(dev, true); |
3a4d5c94 MT |
412 | |
413 | memory->nregions = 0; | |
28457ee6 | 414 | RCU_INIT_POINTER(dev->memory, memory); |
3a4d5c94 MT |
415 | return 0; |
416 | } | |
417 | ||
bab632d6 MT |
418 | /* In case of DMA done not in order in lower device driver for some reason. |
419 | * upend_idx is used to track end of used idx, done_idx is used to track head | |
420 | * of used idx. Once lower device DMA done contiguously, we will signal KVM | |
421 | * guest used idx. | |
422 | */ | |
423 | int vhost_zerocopy_signal_used(struct vhost_virtqueue *vq) | |
424 | { | |
425 | int i; | |
426 | int j = 0; | |
427 | ||
428 | for (i = vq->done_idx; i != vq->upend_idx; i = (i + 1) % UIO_MAXIOV) { | |
429 | if ((vq->heads[i].len == VHOST_DMA_DONE_LEN)) { | |
430 | vq->heads[i].len = VHOST_DMA_CLEAR_LEN; | |
431 | vhost_add_used_and_signal(vq->dev, vq, | |
432 | vq->heads[i].id, 0); | |
433 | ++j; | |
434 | } else | |
435 | break; | |
436 | } | |
437 | if (j) | |
438 | vq->done_idx = i; | |
439 | return j; | |
440 | } | |
441 | ||
ea5d4046 MT |
442 | /* Caller should have device mutex if and only if locked is set */ |
443 | void vhost_dev_cleanup(struct vhost_dev *dev, bool locked) | |
3a4d5c94 MT |
444 | { |
445 | int i; | |
d47effe1 | 446 | |
3a4d5c94 MT |
447 | for (i = 0; i < dev->nvqs; ++i) { |
448 | if (dev->vqs[i].kick && dev->vqs[i].handle_kick) { | |
449 | vhost_poll_stop(&dev->vqs[i].poll); | |
450 | vhost_poll_flush(&dev->vqs[i].poll); | |
451 | } | |
bab632d6 MT |
452 | /* Wait for all lower device DMAs done. */ |
453 | if (dev->vqs[i].ubufs) | |
454 | vhost_ubuf_put_and_wait(dev->vqs[i].ubufs); | |
455 | ||
456 | /* Signal guest as appropriate. */ | |
457 | vhost_zerocopy_signal_used(&dev->vqs[i]); | |
458 | ||
3a4d5c94 MT |
459 | if (dev->vqs[i].error_ctx) |
460 | eventfd_ctx_put(dev->vqs[i].error_ctx); | |
461 | if (dev->vqs[i].error) | |
462 | fput(dev->vqs[i].error); | |
463 | if (dev->vqs[i].kick) | |
464 | fput(dev->vqs[i].kick); | |
465 | if (dev->vqs[i].call_ctx) | |
466 | eventfd_ctx_put(dev->vqs[i].call_ctx); | |
467 | if (dev->vqs[i].call) | |
468 | fput(dev->vqs[i].call); | |
469 | vhost_vq_reset(dev, dev->vqs + i); | |
470 | } | |
e0e9b406 | 471 | vhost_dev_free_iovecs(dev); |
3a4d5c94 MT |
472 | if (dev->log_ctx) |
473 | eventfd_ctx_put(dev->log_ctx); | |
474 | dev->log_ctx = NULL; | |
475 | if (dev->log_file) | |
476 | fput(dev->log_file); | |
477 | dev->log_file = NULL; | |
478 | /* No one will access memory at this point */ | |
28457ee6 | 479 | kfree(rcu_dereference_protected(dev->memory, |
ea5d4046 MT |
480 | locked == |
481 | lockdep_is_held(&dev->mutex))); | |
28457ee6 | 482 | RCU_INIT_POINTER(dev->memory, NULL); |
c23f3445 | 483 | WARN_ON(!list_empty(&dev->work_list)); |
78b620ce ED |
484 | if (dev->worker) { |
485 | kthread_stop(dev->worker); | |
486 | dev->worker = NULL; | |
487 | } | |
533a19b4 MT |
488 | if (dev->mm) |
489 | mmput(dev->mm); | |
490 | dev->mm = NULL; | |
3a4d5c94 MT |
491 | } |
492 | ||
493 | static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz) | |
494 | { | |
495 | u64 a = addr / VHOST_PAGE_SIZE / 8; | |
d47effe1 | 496 | |
3a4d5c94 MT |
497 | /* Make sure 64 bit math will not overflow. */ |
498 | if (a > ULONG_MAX - (unsigned long)log_base || | |
499 | a + (unsigned long)log_base > ULONG_MAX) | |
6d97e55f | 500 | return 0; |
3a4d5c94 MT |
501 | |
502 | return access_ok(VERIFY_WRITE, log_base + a, | |
503 | (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8); | |
504 | } | |
505 | ||
506 | /* Caller should have vq mutex and device mutex. */ | |
507 | static int vq_memory_access_ok(void __user *log_base, struct vhost_memory *mem, | |
508 | int log_all) | |
509 | { | |
510 | int i; | |
179b284e | 511 | |
f8322fbe MT |
512 | if (!mem) |
513 | return 0; | |
179b284e | 514 | |
3a4d5c94 MT |
515 | for (i = 0; i < mem->nregions; ++i) { |
516 | struct vhost_memory_region *m = mem->regions + i; | |
517 | unsigned long a = m->userspace_addr; | |
518 | if (m->memory_size > ULONG_MAX) | |
519 | return 0; | |
520 | else if (!access_ok(VERIFY_WRITE, (void __user *)a, | |
521 | m->memory_size)) | |
522 | return 0; | |
523 | else if (log_all && !log_access_ok(log_base, | |
524 | m->guest_phys_addr, | |
525 | m->memory_size)) | |
526 | return 0; | |
527 | } | |
528 | return 1; | |
529 | } | |
530 | ||
531 | /* Can we switch to this memory table? */ | |
532 | /* Caller should have device mutex but not vq mutex */ | |
533 | static int memory_access_ok(struct vhost_dev *d, struct vhost_memory *mem, | |
534 | int log_all) | |
535 | { | |
536 | int i; | |
d47effe1 | 537 | |
3a4d5c94 MT |
538 | for (i = 0; i < d->nvqs; ++i) { |
539 | int ok; | |
540 | mutex_lock(&d->vqs[i].mutex); | |
541 | /* If ring is inactive, will check when it's enabled. */ | |
542 | if (d->vqs[i].private_data) | |
543 | ok = vq_memory_access_ok(d->vqs[i].log_base, mem, | |
544 | log_all); | |
545 | else | |
546 | ok = 1; | |
547 | mutex_unlock(&d->vqs[i].mutex); | |
548 | if (!ok) | |
549 | return 0; | |
550 | } | |
551 | return 1; | |
552 | } | |
553 | ||
8ea8cf89 | 554 | static int vq_access_ok(struct vhost_dev *d, unsigned int num, |
3a4d5c94 MT |
555 | struct vring_desc __user *desc, |
556 | struct vring_avail __user *avail, | |
557 | struct vring_used __user *used) | |
558 | { | |
8ea8cf89 | 559 | size_t s = vhost_has_feature(d, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; |
3a4d5c94 MT |
560 | return access_ok(VERIFY_READ, desc, num * sizeof *desc) && |
561 | access_ok(VERIFY_READ, avail, | |
8ea8cf89 | 562 | sizeof *avail + num * sizeof *avail->ring + s) && |
3a4d5c94 | 563 | access_ok(VERIFY_WRITE, used, |
8ea8cf89 | 564 | sizeof *used + num * sizeof *used->ring + s); |
3a4d5c94 MT |
565 | } |
566 | ||
567 | /* Can we log writes? */ | |
568 | /* Caller should have device mutex but not vq mutex */ | |
569 | int vhost_log_access_ok(struct vhost_dev *dev) | |
570 | { | |
28457ee6 AB |
571 | struct vhost_memory *mp; |
572 | ||
573 | mp = rcu_dereference_protected(dev->memory, | |
574 | lockdep_is_held(&dev->mutex)); | |
575 | return memory_access_ok(dev, mp, 1); | |
3a4d5c94 MT |
576 | } |
577 | ||
578 | /* Verify access for write logging. */ | |
579 | /* Caller should have vq mutex and device mutex */ | |
8ea8cf89 MT |
580 | static int vq_log_access_ok(struct vhost_dev *d, struct vhost_virtqueue *vq, |
581 | void __user *log_base) | |
3a4d5c94 | 582 | { |
28457ee6 | 583 | struct vhost_memory *mp; |
8ea8cf89 | 584 | size_t s = vhost_has_feature(d, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; |
28457ee6 AB |
585 | |
586 | mp = rcu_dereference_protected(vq->dev->memory, | |
587 | lockdep_is_held(&vq->mutex)); | |
588 | return vq_memory_access_ok(log_base, mp, | |
3a4d5c94 MT |
589 | vhost_has_feature(vq->dev, VHOST_F_LOG_ALL)) && |
590 | (!vq->log_used || log_access_ok(log_base, vq->log_addr, | |
591 | sizeof *vq->used + | |
8ea8cf89 | 592 | vq->num * sizeof *vq->used->ring + s)); |
3a4d5c94 MT |
593 | } |
594 | ||
595 | /* Can we start vq? */ | |
596 | /* Caller should have vq mutex and device mutex */ | |
597 | int vhost_vq_access_ok(struct vhost_virtqueue *vq) | |
598 | { | |
8ea8cf89 MT |
599 | return vq_access_ok(vq->dev, vq->num, vq->desc, vq->avail, vq->used) && |
600 | vq_log_access_ok(vq->dev, vq, vq->log_base); | |
3a4d5c94 MT |
601 | } |
602 | ||
603 | static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) | |
604 | { | |
605 | struct vhost_memory mem, *newmem, *oldmem; | |
606 | unsigned long size = offsetof(struct vhost_memory, regions); | |
d47effe1 | 607 | |
7ad9c9d2 TY |
608 | if (copy_from_user(&mem, m, size)) |
609 | return -EFAULT; | |
3a4d5c94 MT |
610 | if (mem.padding) |
611 | return -EOPNOTSUPP; | |
612 | if (mem.nregions > VHOST_MEMORY_MAX_NREGIONS) | |
613 | return -E2BIG; | |
614 | newmem = kmalloc(size + mem.nregions * sizeof *m->regions, GFP_KERNEL); | |
615 | if (!newmem) | |
616 | return -ENOMEM; | |
617 | ||
618 | memcpy(newmem, &mem, size); | |
7ad9c9d2 TY |
619 | if (copy_from_user(newmem->regions, m->regions, |
620 | mem.nregions * sizeof *m->regions)) { | |
3a4d5c94 | 621 | kfree(newmem); |
7ad9c9d2 | 622 | return -EFAULT; |
3a4d5c94 MT |
623 | } |
624 | ||
d47effe1 KK |
625 | if (!memory_access_ok(d, newmem, |
626 | vhost_has_feature(d, VHOST_F_LOG_ALL))) { | |
a02c3789 | 627 | kfree(newmem); |
3a4d5c94 | 628 | return -EFAULT; |
a02c3789 | 629 | } |
28457ee6 AB |
630 | oldmem = rcu_dereference_protected(d->memory, |
631 | lockdep_is_held(&d->mutex)); | |
3a4d5c94 MT |
632 | rcu_assign_pointer(d->memory, newmem); |
633 | synchronize_rcu(); | |
634 | kfree(oldmem); | |
635 | return 0; | |
636 | } | |
637 | ||
3a4d5c94 MT |
638 | static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp) |
639 | { | |
640 | struct file *eventfp, *filep = NULL, | |
641 | *pollstart = NULL, *pollstop = NULL; | |
642 | struct eventfd_ctx *ctx = NULL; | |
643 | u32 __user *idxp = argp; | |
644 | struct vhost_virtqueue *vq; | |
645 | struct vhost_vring_state s; | |
646 | struct vhost_vring_file f; | |
647 | struct vhost_vring_addr a; | |
648 | u32 idx; | |
649 | long r; | |
650 | ||
651 | r = get_user(idx, idxp); | |
652 | if (r < 0) | |
653 | return r; | |
0f3d9a17 | 654 | if (idx >= d->nvqs) |
3a4d5c94 MT |
655 | return -ENOBUFS; |
656 | ||
657 | vq = d->vqs + idx; | |
658 | ||
659 | mutex_lock(&vq->mutex); | |
660 | ||
661 | switch (ioctl) { | |
662 | case VHOST_SET_VRING_NUM: | |
663 | /* Resizing ring with an active backend? | |
664 | * You don't want to do that. */ | |
665 | if (vq->private_data) { | |
666 | r = -EBUSY; | |
667 | break; | |
668 | } | |
7ad9c9d2 TY |
669 | if (copy_from_user(&s, argp, sizeof s)) { |
670 | r = -EFAULT; | |
3a4d5c94 | 671 | break; |
7ad9c9d2 | 672 | } |
3a4d5c94 MT |
673 | if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) { |
674 | r = -EINVAL; | |
675 | break; | |
676 | } | |
677 | vq->num = s.num; | |
678 | break; | |
679 | case VHOST_SET_VRING_BASE: | |
680 | /* Moving base with an active backend? | |
681 | * You don't want to do that. */ | |
682 | if (vq->private_data) { | |
683 | r = -EBUSY; | |
684 | break; | |
685 | } | |
7ad9c9d2 TY |
686 | if (copy_from_user(&s, argp, sizeof s)) { |
687 | r = -EFAULT; | |
3a4d5c94 | 688 | break; |
7ad9c9d2 | 689 | } |
3a4d5c94 MT |
690 | if (s.num > 0xffff) { |
691 | r = -EINVAL; | |
692 | break; | |
693 | } | |
694 | vq->last_avail_idx = s.num; | |
695 | /* Forget the cached index value. */ | |
696 | vq->avail_idx = vq->last_avail_idx; | |
697 | break; | |
698 | case VHOST_GET_VRING_BASE: | |
699 | s.index = idx; | |
700 | s.num = vq->last_avail_idx; | |
7ad9c9d2 TY |
701 | if (copy_to_user(argp, &s, sizeof s)) |
702 | r = -EFAULT; | |
3a4d5c94 MT |
703 | break; |
704 | case VHOST_SET_VRING_ADDR: | |
7ad9c9d2 TY |
705 | if (copy_from_user(&a, argp, sizeof a)) { |
706 | r = -EFAULT; | |
3a4d5c94 | 707 | break; |
7ad9c9d2 | 708 | } |
3a4d5c94 MT |
709 | if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) { |
710 | r = -EOPNOTSUPP; | |
711 | break; | |
712 | } | |
713 | /* For 32bit, verify that the top 32bits of the user | |
714 | data are set to zero. */ | |
715 | if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr || | |
716 | (u64)(unsigned long)a.used_user_addr != a.used_user_addr || | |
717 | (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) { | |
718 | r = -EFAULT; | |
719 | break; | |
720 | } | |
721 | if ((a.avail_user_addr & (sizeof *vq->avail->ring - 1)) || | |
722 | (a.used_user_addr & (sizeof *vq->used->ring - 1)) || | |
723 | (a.log_guest_addr & (sizeof *vq->used->ring - 1))) { | |
724 | r = -EINVAL; | |
725 | break; | |
726 | } | |
727 | ||
728 | /* We only verify access here if backend is configured. | |
729 | * If it is not, we don't as size might not have been setup. | |
730 | * We will verify when backend is configured. */ | |
731 | if (vq->private_data) { | |
8ea8cf89 | 732 | if (!vq_access_ok(d, vq->num, |
3a4d5c94 MT |
733 | (void __user *)(unsigned long)a.desc_user_addr, |
734 | (void __user *)(unsigned long)a.avail_user_addr, | |
735 | (void __user *)(unsigned long)a.used_user_addr)) { | |
736 | r = -EINVAL; | |
737 | break; | |
738 | } | |
739 | ||
740 | /* Also validate log access for used ring if enabled. */ | |
741 | if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) && | |
742 | !log_access_ok(vq->log_base, a.log_guest_addr, | |
743 | sizeof *vq->used + | |
744 | vq->num * sizeof *vq->used->ring)) { | |
745 | r = -EINVAL; | |
746 | break; | |
747 | } | |
748 | } | |
749 | ||
3a4d5c94 MT |
750 | vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG)); |
751 | vq->desc = (void __user *)(unsigned long)a.desc_user_addr; | |
752 | vq->avail = (void __user *)(unsigned long)a.avail_user_addr; | |
753 | vq->log_addr = a.log_guest_addr; | |
754 | vq->used = (void __user *)(unsigned long)a.used_user_addr; | |
755 | break; | |
756 | case VHOST_SET_VRING_KICK: | |
7ad9c9d2 TY |
757 | if (copy_from_user(&f, argp, sizeof f)) { |
758 | r = -EFAULT; | |
3a4d5c94 | 759 | break; |
7ad9c9d2 | 760 | } |
3a4d5c94 | 761 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
762 | if (IS_ERR(eventfp)) { |
763 | r = PTR_ERR(eventfp); | |
764 | break; | |
765 | } | |
3a4d5c94 MT |
766 | if (eventfp != vq->kick) { |
767 | pollstop = filep = vq->kick; | |
768 | pollstart = vq->kick = eventfp; | |
769 | } else | |
770 | filep = eventfp; | |
771 | break; | |
772 | case VHOST_SET_VRING_CALL: | |
7ad9c9d2 TY |
773 | if (copy_from_user(&f, argp, sizeof f)) { |
774 | r = -EFAULT; | |
3a4d5c94 | 775 | break; |
7ad9c9d2 | 776 | } |
3a4d5c94 | 777 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
778 | if (IS_ERR(eventfp)) { |
779 | r = PTR_ERR(eventfp); | |
780 | break; | |
781 | } | |
3a4d5c94 MT |
782 | if (eventfp != vq->call) { |
783 | filep = vq->call; | |
784 | ctx = vq->call_ctx; | |
785 | vq->call = eventfp; | |
786 | vq->call_ctx = eventfp ? | |
787 | eventfd_ctx_fileget(eventfp) : NULL; | |
788 | } else | |
789 | filep = eventfp; | |
790 | break; | |
791 | case VHOST_SET_VRING_ERR: | |
7ad9c9d2 TY |
792 | if (copy_from_user(&f, argp, sizeof f)) { |
793 | r = -EFAULT; | |
3a4d5c94 | 794 | break; |
7ad9c9d2 | 795 | } |
3a4d5c94 | 796 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
797 | if (IS_ERR(eventfp)) { |
798 | r = PTR_ERR(eventfp); | |
799 | break; | |
800 | } | |
3a4d5c94 MT |
801 | if (eventfp != vq->error) { |
802 | filep = vq->error; | |
803 | vq->error = eventfp; | |
804 | ctx = vq->error_ctx; | |
805 | vq->error_ctx = eventfp ? | |
806 | eventfd_ctx_fileget(eventfp) : NULL; | |
807 | } else | |
808 | filep = eventfp; | |
809 | break; | |
810 | default: | |
811 | r = -ENOIOCTLCMD; | |
812 | } | |
813 | ||
814 | if (pollstop && vq->handle_kick) | |
815 | vhost_poll_stop(&vq->poll); | |
816 | ||
817 | if (ctx) | |
818 | eventfd_ctx_put(ctx); | |
819 | if (filep) | |
820 | fput(filep); | |
821 | ||
822 | if (pollstart && vq->handle_kick) | |
823 | vhost_poll_start(&vq->poll, vq->kick); | |
824 | ||
825 | mutex_unlock(&vq->mutex); | |
826 | ||
827 | if (pollstop && vq->handle_kick) | |
828 | vhost_poll_flush(&vq->poll); | |
829 | return r; | |
830 | } | |
831 | ||
832 | /* Caller must have device mutex */ | |
833 | long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, unsigned long arg) | |
834 | { | |
835 | void __user *argp = (void __user *)arg; | |
836 | struct file *eventfp, *filep = NULL; | |
837 | struct eventfd_ctx *ctx = NULL; | |
838 | u64 p; | |
839 | long r; | |
840 | int i, fd; | |
841 | ||
842 | /* If you are not the owner, you can become one */ | |
843 | if (ioctl == VHOST_SET_OWNER) { | |
844 | r = vhost_dev_set_owner(d); | |
845 | goto done; | |
846 | } | |
847 | ||
848 | /* You must be the owner to do anything else */ | |
849 | r = vhost_dev_check_owner(d); | |
850 | if (r) | |
851 | goto done; | |
852 | ||
853 | switch (ioctl) { | |
854 | case VHOST_SET_MEM_TABLE: | |
855 | r = vhost_set_memory(d, argp); | |
856 | break; | |
857 | case VHOST_SET_LOG_BASE: | |
7ad9c9d2 TY |
858 | if (copy_from_user(&p, argp, sizeof p)) { |
859 | r = -EFAULT; | |
3a4d5c94 | 860 | break; |
7ad9c9d2 | 861 | } |
3a4d5c94 MT |
862 | if ((u64)(unsigned long)p != p) { |
863 | r = -EFAULT; | |
864 | break; | |
865 | } | |
866 | for (i = 0; i < d->nvqs; ++i) { | |
867 | struct vhost_virtqueue *vq; | |
868 | void __user *base = (void __user *)(unsigned long)p; | |
869 | vq = d->vqs + i; | |
870 | mutex_lock(&vq->mutex); | |
871 | /* If ring is inactive, will check when it's enabled. */ | |
8ea8cf89 | 872 | if (vq->private_data && !vq_log_access_ok(d, vq, base)) |
3a4d5c94 MT |
873 | r = -EFAULT; |
874 | else | |
875 | vq->log_base = base; | |
876 | mutex_unlock(&vq->mutex); | |
877 | } | |
878 | break; | |
879 | case VHOST_SET_LOG_FD: | |
880 | r = get_user(fd, (int __user *)argp); | |
881 | if (r < 0) | |
882 | break; | |
883 | eventfp = fd == -1 ? NULL : eventfd_fget(fd); | |
884 | if (IS_ERR(eventfp)) { | |
885 | r = PTR_ERR(eventfp); | |
886 | break; | |
887 | } | |
888 | if (eventfp != d->log_file) { | |
889 | filep = d->log_file; | |
890 | ctx = d->log_ctx; | |
891 | d->log_ctx = eventfp ? | |
892 | eventfd_ctx_fileget(eventfp) : NULL; | |
893 | } else | |
894 | filep = eventfp; | |
895 | for (i = 0; i < d->nvqs; ++i) { | |
896 | mutex_lock(&d->vqs[i].mutex); | |
897 | d->vqs[i].log_ctx = d->log_ctx; | |
898 | mutex_unlock(&d->vqs[i].mutex); | |
899 | } | |
900 | if (ctx) | |
901 | eventfd_ctx_put(ctx); | |
902 | if (filep) | |
903 | fput(filep); | |
904 | break; | |
905 | default: | |
906 | r = vhost_set_vring(d, ioctl, argp); | |
907 | break; | |
908 | } | |
909 | done: | |
910 | return r; | |
911 | } | |
912 | ||
913 | static const struct vhost_memory_region *find_region(struct vhost_memory *mem, | |
914 | __u64 addr, __u32 len) | |
915 | { | |
916 | struct vhost_memory_region *reg; | |
917 | int i; | |
d47effe1 | 918 | |
3a4d5c94 MT |
919 | /* linear search is not brilliant, but we really have on the order of 6 |
920 | * regions in practice */ | |
921 | for (i = 0; i < mem->nregions; ++i) { | |
922 | reg = mem->regions + i; | |
923 | if (reg->guest_phys_addr <= addr && | |
924 | reg->guest_phys_addr + reg->memory_size - 1 >= addr) | |
925 | return reg; | |
926 | } | |
927 | return NULL; | |
928 | } | |
929 | ||
930 | /* TODO: This is really inefficient. We need something like get_user() | |
931 | * (instruction directly accesses the data, with an exception table entry | |
932 | * returning -EFAULT). See Documentation/x86/exception-tables.txt. | |
933 | */ | |
934 | static int set_bit_to_user(int nr, void __user *addr) | |
935 | { | |
936 | unsigned long log = (unsigned long)addr; | |
937 | struct page *page; | |
938 | void *base; | |
939 | int bit = nr + (log % PAGE_SIZE) * 8; | |
940 | int r; | |
d47effe1 | 941 | |
3a4d5c94 | 942 | r = get_user_pages_fast(log, 1, 1, &page); |
d6db3f5c | 943 | if (r < 0) |
3a4d5c94 | 944 | return r; |
d6db3f5c | 945 | BUG_ON(r != 1); |
c6daa7ff | 946 | base = kmap_atomic(page); |
3a4d5c94 | 947 | set_bit(bit, base); |
c6daa7ff | 948 | kunmap_atomic(base); |
3a4d5c94 MT |
949 | set_page_dirty_lock(page); |
950 | put_page(page); | |
951 | return 0; | |
952 | } | |
953 | ||
954 | static int log_write(void __user *log_base, | |
955 | u64 write_address, u64 write_length) | |
956 | { | |
28831ee6 | 957 | u64 write_page = write_address / VHOST_PAGE_SIZE; |
3a4d5c94 | 958 | int r; |
d47effe1 | 959 | |
3a4d5c94 MT |
960 | if (!write_length) |
961 | return 0; | |
3bf9be40 | 962 | write_length += write_address % VHOST_PAGE_SIZE; |
3a4d5c94 MT |
963 | for (;;) { |
964 | u64 base = (u64)(unsigned long)log_base; | |
28831ee6 MT |
965 | u64 log = base + write_page / 8; |
966 | int bit = write_page % 8; | |
3a4d5c94 MT |
967 | if ((u64)(unsigned long)log != log) |
968 | return -EFAULT; | |
969 | r = set_bit_to_user(bit, (void __user *)(unsigned long)log); | |
970 | if (r < 0) | |
971 | return r; | |
972 | if (write_length <= VHOST_PAGE_SIZE) | |
973 | break; | |
974 | write_length -= VHOST_PAGE_SIZE; | |
28831ee6 | 975 | write_page += 1; |
3a4d5c94 MT |
976 | } |
977 | return r; | |
978 | } | |
979 | ||
980 | int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, | |
981 | unsigned int log_num, u64 len) | |
982 | { | |
983 | int i, r; | |
984 | ||
985 | /* Make sure data written is seen before log. */ | |
5659338c | 986 | smp_wmb(); |
3a4d5c94 MT |
987 | for (i = 0; i < log_num; ++i) { |
988 | u64 l = min(log[i].len, len); | |
989 | r = log_write(vq->log_base, log[i].addr, l); | |
990 | if (r < 0) | |
991 | return r; | |
992 | len -= l; | |
5786aee8 MT |
993 | if (!len) { |
994 | if (vq->log_ctx) | |
995 | eventfd_signal(vq->log_ctx, 1); | |
3a4d5c94 | 996 | return 0; |
5786aee8 | 997 | } |
3a4d5c94 | 998 | } |
3a4d5c94 MT |
999 | /* Length written exceeds what we have stored. This is a bug. */ |
1000 | BUG(); | |
1001 | return 0; | |
1002 | } | |
1003 | ||
2723feaa JW |
1004 | static int vhost_update_used_flags(struct vhost_virtqueue *vq) |
1005 | { | |
1006 | void __user *used; | |
b834226b | 1007 | if (__put_user(vq->used_flags, &vq->used->flags) < 0) |
2723feaa JW |
1008 | return -EFAULT; |
1009 | if (unlikely(vq->log_used)) { | |
1010 | /* Make sure the flag is seen before log. */ | |
1011 | smp_wmb(); | |
1012 | /* Log used flag write. */ | |
1013 | used = &vq->used->flags; | |
1014 | log_write(vq->log_base, vq->log_addr + | |
1015 | (used - (void __user *)vq->used), | |
1016 | sizeof vq->used->flags); | |
1017 | if (vq->log_ctx) | |
1018 | eventfd_signal(vq->log_ctx, 1); | |
1019 | } | |
1020 | return 0; | |
1021 | } | |
1022 | ||
1023 | static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event) | |
1024 | { | |
b834226b | 1025 | if (__put_user(vq->avail_idx, vhost_avail_event(vq))) |
2723feaa JW |
1026 | return -EFAULT; |
1027 | if (unlikely(vq->log_used)) { | |
1028 | void __user *used; | |
1029 | /* Make sure the event is seen before log. */ | |
1030 | smp_wmb(); | |
1031 | /* Log avail event write */ | |
1032 | used = vhost_avail_event(vq); | |
1033 | log_write(vq->log_base, vq->log_addr + | |
1034 | (used - (void __user *)vq->used), | |
1035 | sizeof *vhost_avail_event(vq)); | |
1036 | if (vq->log_ctx) | |
1037 | eventfd_signal(vq->log_ctx, 1); | |
1038 | } | |
1039 | return 0; | |
1040 | } | |
1041 | ||
1042 | int vhost_init_used(struct vhost_virtqueue *vq) | |
1043 | { | |
1044 | int r; | |
1045 | if (!vq->private_data) | |
1046 | return 0; | |
1047 | ||
1048 | r = vhost_update_used_flags(vq); | |
1049 | if (r) | |
1050 | return r; | |
1051 | vq->signalled_used_valid = false; | |
1052 | return get_user(vq->last_used_idx, &vq->used->idx); | |
1053 | } | |
1054 | ||
a8d3782f CH |
1055 | static int translate_desc(struct vhost_dev *dev, u64 addr, u32 len, |
1056 | struct iovec iov[], int iov_size) | |
3a4d5c94 MT |
1057 | { |
1058 | const struct vhost_memory_region *reg; | |
1059 | struct vhost_memory *mem; | |
1060 | struct iovec *_iov; | |
1061 | u64 s = 0; | |
1062 | int ret = 0; | |
1063 | ||
1064 | rcu_read_lock(); | |
1065 | ||
1066 | mem = rcu_dereference(dev->memory); | |
1067 | while ((u64)len > s) { | |
1068 | u64 size; | |
7b3384fc | 1069 | if (unlikely(ret >= iov_size)) { |
3a4d5c94 MT |
1070 | ret = -ENOBUFS; |
1071 | break; | |
1072 | } | |
1073 | reg = find_region(mem, addr, len); | |
7b3384fc | 1074 | if (unlikely(!reg)) { |
3a4d5c94 MT |
1075 | ret = -EFAULT; |
1076 | break; | |
1077 | } | |
1078 | _iov = iov + ret; | |
1079 | size = reg->memory_size - addr + reg->guest_phys_addr; | |
1080 | _iov->iov_len = min((u64)len, size); | |
a8d3782f | 1081 | _iov->iov_base = (void __user *)(unsigned long) |
3a4d5c94 MT |
1082 | (reg->userspace_addr + addr - reg->guest_phys_addr); |
1083 | s += size; | |
1084 | addr += size; | |
1085 | ++ret; | |
1086 | } | |
1087 | ||
1088 | rcu_read_unlock(); | |
1089 | return ret; | |
1090 | } | |
1091 | ||
1092 | /* Each buffer in the virtqueues is actually a chain of descriptors. This | |
1093 | * function returns the next descriptor in the chain, | |
1094 | * or -1U if we're at the end. */ | |
1095 | static unsigned next_desc(struct vring_desc *desc) | |
1096 | { | |
1097 | unsigned int next; | |
1098 | ||
1099 | /* If this descriptor says it doesn't chain, we're done. */ | |
1100 | if (!(desc->flags & VRING_DESC_F_NEXT)) | |
1101 | return -1U; | |
1102 | ||
1103 | /* Check they're not leading us off end of descriptors. */ | |
1104 | next = desc->next; | |
1105 | /* Make sure compiler knows to grab that: we don't want it changing! */ | |
1106 | /* We will use the result as an index in an array, so most | |
1107 | * architectures only need a compiler barrier here. */ | |
1108 | read_barrier_depends(); | |
1109 | ||
1110 | return next; | |
1111 | } | |
1112 | ||
7b3384fc MT |
1113 | static int get_indirect(struct vhost_dev *dev, struct vhost_virtqueue *vq, |
1114 | struct iovec iov[], unsigned int iov_size, | |
1115 | unsigned int *out_num, unsigned int *in_num, | |
1116 | struct vhost_log *log, unsigned int *log_num, | |
1117 | struct vring_desc *indirect) | |
3a4d5c94 MT |
1118 | { |
1119 | struct vring_desc desc; | |
1120 | unsigned int i = 0, count, found = 0; | |
1121 | int ret; | |
1122 | ||
1123 | /* Sanity check */ | |
7b3384fc | 1124 | if (unlikely(indirect->len % sizeof desc)) { |
3a4d5c94 MT |
1125 | vq_err(vq, "Invalid length in indirect descriptor: " |
1126 | "len 0x%llx not multiple of 0x%zx\n", | |
1127 | (unsigned long long)indirect->len, | |
1128 | sizeof desc); | |
1129 | return -EINVAL; | |
1130 | } | |
1131 | ||
1132 | ret = translate_desc(dev, indirect->addr, indirect->len, vq->indirect, | |
e0e9b406 | 1133 | UIO_MAXIOV); |
7b3384fc | 1134 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1135 | vq_err(vq, "Translation failure %d in indirect.\n", ret); |
1136 | return ret; | |
1137 | } | |
1138 | ||
1139 | /* We will use the result as an address to read from, so most | |
1140 | * architectures only need a compiler barrier here. */ | |
1141 | read_barrier_depends(); | |
1142 | ||
1143 | count = indirect->len / sizeof desc; | |
1144 | /* Buffers are chained via a 16 bit next field, so | |
1145 | * we can have at most 2^16 of these. */ | |
7b3384fc | 1146 | if (unlikely(count > USHRT_MAX + 1)) { |
3a4d5c94 MT |
1147 | vq_err(vq, "Indirect buffer length too big: %d\n", |
1148 | indirect->len); | |
1149 | return -E2BIG; | |
1150 | } | |
1151 | ||
1152 | do { | |
1153 | unsigned iov_count = *in_num + *out_num; | |
7b3384fc | 1154 | if (unlikely(++found > count)) { |
3a4d5c94 MT |
1155 | vq_err(vq, "Loop detected: last one at %u " |
1156 | "indirect size %u\n", | |
1157 | i, count); | |
1158 | return -EINVAL; | |
1159 | } | |
d47effe1 KK |
1160 | if (unlikely(memcpy_fromiovec((unsigned char *)&desc, |
1161 | vq->indirect, sizeof desc))) { | |
3a4d5c94 MT |
1162 | vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n", |
1163 | i, (size_t)indirect->addr + i * sizeof desc); | |
1164 | return -EINVAL; | |
1165 | } | |
7b3384fc | 1166 | if (unlikely(desc.flags & VRING_DESC_F_INDIRECT)) { |
3a4d5c94 MT |
1167 | vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n", |
1168 | i, (size_t)indirect->addr + i * sizeof desc); | |
1169 | return -EINVAL; | |
1170 | } | |
1171 | ||
1172 | ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, | |
1173 | iov_size - iov_count); | |
7b3384fc | 1174 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1175 | vq_err(vq, "Translation failure %d indirect idx %d\n", |
1176 | ret, i); | |
1177 | return ret; | |
1178 | } | |
1179 | /* If this is an input descriptor, increment that count. */ | |
1180 | if (desc.flags & VRING_DESC_F_WRITE) { | |
1181 | *in_num += ret; | |
1182 | if (unlikely(log)) { | |
1183 | log[*log_num].addr = desc.addr; | |
1184 | log[*log_num].len = desc.len; | |
1185 | ++*log_num; | |
1186 | } | |
1187 | } else { | |
1188 | /* If it's an output descriptor, they're all supposed | |
1189 | * to come before any input descriptors. */ | |
7b3384fc | 1190 | if (unlikely(*in_num)) { |
3a4d5c94 MT |
1191 | vq_err(vq, "Indirect descriptor " |
1192 | "has out after in: idx %d\n", i); | |
1193 | return -EINVAL; | |
1194 | } | |
1195 | *out_num += ret; | |
1196 | } | |
1197 | } while ((i = next_desc(&desc)) != -1); | |
1198 | return 0; | |
1199 | } | |
1200 | ||
1201 | /* This looks in the virtqueue and for the first available buffer, and converts | |
1202 | * it to an iovec for convenient access. Since descriptors consist of some | |
1203 | * number of output then some number of input descriptors, it's actually two | |
1204 | * iovecs, but we pack them into one and note how many of each there were. | |
1205 | * | |
d5675bd2 MT |
1206 | * This function returns the descriptor number found, or vq->num (which is |
1207 | * never a valid descriptor number) if none was found. A negative code is | |
1208 | * returned on error. */ | |
1209 | int vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq, | |
1210 | struct iovec iov[], unsigned int iov_size, | |
1211 | unsigned int *out_num, unsigned int *in_num, | |
1212 | struct vhost_log *log, unsigned int *log_num) | |
3a4d5c94 MT |
1213 | { |
1214 | struct vring_desc desc; | |
1215 | unsigned int i, head, found = 0; | |
1216 | u16 last_avail_idx; | |
1217 | int ret; | |
1218 | ||
1219 | /* Check it isn't doing very strange things with descriptor numbers. */ | |
1220 | last_avail_idx = vq->last_avail_idx; | |
8b7347aa | 1221 | if (unlikely(__get_user(vq->avail_idx, &vq->avail->idx))) { |
3a4d5c94 MT |
1222 | vq_err(vq, "Failed to access avail idx at %p\n", |
1223 | &vq->avail->idx); | |
d5675bd2 | 1224 | return -EFAULT; |
3a4d5c94 MT |
1225 | } |
1226 | ||
7b3384fc | 1227 | if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) { |
3a4d5c94 MT |
1228 | vq_err(vq, "Guest moved used index from %u to %u", |
1229 | last_avail_idx, vq->avail_idx); | |
d5675bd2 | 1230 | return -EFAULT; |
3a4d5c94 MT |
1231 | } |
1232 | ||
1233 | /* If there's nothing new since last we looked, return invalid. */ | |
1234 | if (vq->avail_idx == last_avail_idx) | |
1235 | return vq->num; | |
1236 | ||
1237 | /* Only get avail ring entries after they have been exposed by guest. */ | |
5659338c | 1238 | smp_rmb(); |
3a4d5c94 MT |
1239 | |
1240 | /* Grab the next descriptor number they're advertising, and increment | |
1241 | * the index we've seen. */ | |
8b7347aa MT |
1242 | if (unlikely(__get_user(head, |
1243 | &vq->avail->ring[last_avail_idx % vq->num]))) { | |
3a4d5c94 MT |
1244 | vq_err(vq, "Failed to read head: idx %d address %p\n", |
1245 | last_avail_idx, | |
1246 | &vq->avail->ring[last_avail_idx % vq->num]); | |
d5675bd2 | 1247 | return -EFAULT; |
3a4d5c94 MT |
1248 | } |
1249 | ||
1250 | /* If their number is silly, that's an error. */ | |
7b3384fc | 1251 | if (unlikely(head >= vq->num)) { |
3a4d5c94 MT |
1252 | vq_err(vq, "Guest says index %u > %u is available", |
1253 | head, vq->num); | |
d5675bd2 | 1254 | return -EINVAL; |
3a4d5c94 MT |
1255 | } |
1256 | ||
1257 | /* When we start there are none of either input nor output. */ | |
1258 | *out_num = *in_num = 0; | |
1259 | if (unlikely(log)) | |
1260 | *log_num = 0; | |
1261 | ||
1262 | i = head; | |
1263 | do { | |
1264 | unsigned iov_count = *in_num + *out_num; | |
7b3384fc | 1265 | if (unlikely(i >= vq->num)) { |
3a4d5c94 MT |
1266 | vq_err(vq, "Desc index is %u > %u, head = %u", |
1267 | i, vq->num, head); | |
d5675bd2 | 1268 | return -EINVAL; |
3a4d5c94 | 1269 | } |
7b3384fc | 1270 | if (unlikely(++found > vq->num)) { |
3a4d5c94 MT |
1271 | vq_err(vq, "Loop detected: last one at %u " |
1272 | "vq size %u head %u\n", | |
1273 | i, vq->num, head); | |
d5675bd2 | 1274 | return -EINVAL; |
3a4d5c94 | 1275 | } |
fcc042a2 | 1276 | ret = __copy_from_user(&desc, vq->desc + i, sizeof desc); |
7b3384fc | 1277 | if (unlikely(ret)) { |
3a4d5c94 MT |
1278 | vq_err(vq, "Failed to get descriptor: idx %d addr %p\n", |
1279 | i, vq->desc + i); | |
d5675bd2 | 1280 | return -EFAULT; |
3a4d5c94 MT |
1281 | } |
1282 | if (desc.flags & VRING_DESC_F_INDIRECT) { | |
1283 | ret = get_indirect(dev, vq, iov, iov_size, | |
1284 | out_num, in_num, | |
1285 | log, log_num, &desc); | |
7b3384fc | 1286 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1287 | vq_err(vq, "Failure detected " |
1288 | "in indirect descriptor at idx %d\n", i); | |
d5675bd2 | 1289 | return ret; |
3a4d5c94 MT |
1290 | } |
1291 | continue; | |
1292 | } | |
1293 | ||
1294 | ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, | |
1295 | iov_size - iov_count); | |
7b3384fc | 1296 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1297 | vq_err(vq, "Translation failure %d descriptor idx %d\n", |
1298 | ret, i); | |
d5675bd2 | 1299 | return ret; |
3a4d5c94 MT |
1300 | } |
1301 | if (desc.flags & VRING_DESC_F_WRITE) { | |
1302 | /* If this is an input descriptor, | |
1303 | * increment that count. */ | |
1304 | *in_num += ret; | |
1305 | if (unlikely(log)) { | |
1306 | log[*log_num].addr = desc.addr; | |
1307 | log[*log_num].len = desc.len; | |
1308 | ++*log_num; | |
1309 | } | |
1310 | } else { | |
1311 | /* If it's an output descriptor, they're all supposed | |
1312 | * to come before any input descriptors. */ | |
7b3384fc | 1313 | if (unlikely(*in_num)) { |
3a4d5c94 MT |
1314 | vq_err(vq, "Descriptor has out after in: " |
1315 | "idx %d\n", i); | |
d5675bd2 | 1316 | return -EINVAL; |
3a4d5c94 MT |
1317 | } |
1318 | *out_num += ret; | |
1319 | } | |
1320 | } while ((i = next_desc(&desc)) != -1); | |
1321 | ||
1322 | /* On success, increment avail index. */ | |
1323 | vq->last_avail_idx++; | |
8ea8cf89 MT |
1324 | |
1325 | /* Assume notifications from guest are disabled at this point, | |
1326 | * if they aren't we would need to update avail_event index. */ | |
1327 | BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY)); | |
3a4d5c94 MT |
1328 | return head; |
1329 | } | |
1330 | ||
1331 | /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */ | |
8dd014ad | 1332 | void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n) |
3a4d5c94 | 1333 | { |
8dd014ad | 1334 | vq->last_avail_idx -= n; |
3a4d5c94 MT |
1335 | } |
1336 | ||
1337 | /* After we've used one of their buffers, we tell them about it. We'll then | |
1338 | * want to notify the guest, using eventfd. */ | |
1339 | int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len) | |
1340 | { | |
a8d3782f | 1341 | struct vring_used_elem __user *used; |
3a4d5c94 MT |
1342 | |
1343 | /* The virtqueue contains a ring of used buffers. Get a pointer to the | |
1344 | * next entry in that used ring. */ | |
1345 | used = &vq->used->ring[vq->last_used_idx % vq->num]; | |
8b7347aa | 1346 | if (__put_user(head, &used->id)) { |
3a4d5c94 MT |
1347 | vq_err(vq, "Failed to write used id"); |
1348 | return -EFAULT; | |
1349 | } | |
8b7347aa | 1350 | if (__put_user(len, &used->len)) { |
3a4d5c94 MT |
1351 | vq_err(vq, "Failed to write used len"); |
1352 | return -EFAULT; | |
1353 | } | |
1354 | /* Make sure buffer is written before we update index. */ | |
5659338c | 1355 | smp_wmb(); |
8b7347aa | 1356 | if (__put_user(vq->last_used_idx + 1, &vq->used->idx)) { |
3a4d5c94 MT |
1357 | vq_err(vq, "Failed to increment used idx"); |
1358 | return -EFAULT; | |
1359 | } | |
1360 | if (unlikely(vq->log_used)) { | |
1361 | /* Make sure data is seen before log. */ | |
5659338c | 1362 | smp_wmb(); |
86e9424d MT |
1363 | /* Log used ring entry write. */ |
1364 | log_write(vq->log_base, | |
a8d3782f CH |
1365 | vq->log_addr + |
1366 | ((void __user *)used - (void __user *)vq->used), | |
86e9424d MT |
1367 | sizeof *used); |
1368 | /* Log used index update. */ | |
1369 | log_write(vq->log_base, | |
1370 | vq->log_addr + offsetof(struct vring_used, idx), | |
1371 | sizeof vq->used->idx); | |
3a4d5c94 MT |
1372 | if (vq->log_ctx) |
1373 | eventfd_signal(vq->log_ctx, 1); | |
1374 | } | |
1375 | vq->last_used_idx++; | |
8ea8cf89 MT |
1376 | /* If the driver never bothers to signal in a very long while, |
1377 | * used index might wrap around. If that happens, invalidate | |
1378 | * signalled_used index we stored. TODO: make sure driver | |
1379 | * signals at least once in 2^16 and remove this. */ | |
1380 | if (unlikely(vq->last_used_idx == vq->signalled_used)) | |
1381 | vq->signalled_used_valid = false; | |
3a4d5c94 MT |
1382 | return 0; |
1383 | } | |
1384 | ||
8dd014ad DS |
1385 | static int __vhost_add_used_n(struct vhost_virtqueue *vq, |
1386 | struct vring_used_elem *heads, | |
1387 | unsigned count) | |
1388 | { | |
1389 | struct vring_used_elem __user *used; | |
8ea8cf89 | 1390 | u16 old, new; |
8dd014ad DS |
1391 | int start; |
1392 | ||
1393 | start = vq->last_used_idx % vq->num; | |
1394 | used = vq->used->ring + start; | |
dfe5ac5b | 1395 | if (__copy_to_user(used, heads, count * sizeof *used)) { |
8dd014ad DS |
1396 | vq_err(vq, "Failed to write used"); |
1397 | return -EFAULT; | |
1398 | } | |
1399 | if (unlikely(vq->log_used)) { | |
1400 | /* Make sure data is seen before log. */ | |
1401 | smp_wmb(); | |
1402 | /* Log used ring entry write. */ | |
1403 | log_write(vq->log_base, | |
1404 | vq->log_addr + | |
1405 | ((void __user *)used - (void __user *)vq->used), | |
1406 | count * sizeof *used); | |
1407 | } | |
8ea8cf89 MT |
1408 | old = vq->last_used_idx; |
1409 | new = (vq->last_used_idx += count); | |
1410 | /* If the driver never bothers to signal in a very long while, | |
1411 | * used index might wrap around. If that happens, invalidate | |
1412 | * signalled_used index we stored. TODO: make sure driver | |
1413 | * signals at least once in 2^16 and remove this. */ | |
1414 | if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old))) | |
1415 | vq->signalled_used_valid = false; | |
8dd014ad DS |
1416 | return 0; |
1417 | } | |
1418 | ||
1419 | /* After we've used one of their buffers, we tell them about it. We'll then | |
1420 | * want to notify the guest, using eventfd. */ | |
1421 | int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads, | |
1422 | unsigned count) | |
1423 | { | |
1424 | int start, n, r; | |
1425 | ||
1426 | start = vq->last_used_idx % vq->num; | |
1427 | n = vq->num - start; | |
1428 | if (n < count) { | |
1429 | r = __vhost_add_used_n(vq, heads, n); | |
1430 | if (r < 0) | |
1431 | return r; | |
1432 | heads += n; | |
1433 | count -= n; | |
1434 | } | |
1435 | r = __vhost_add_used_n(vq, heads, count); | |
1436 | ||
1437 | /* Make sure buffer is written before we update index. */ | |
1438 | smp_wmb(); | |
1439 | if (put_user(vq->last_used_idx, &vq->used->idx)) { | |
1440 | vq_err(vq, "Failed to increment used idx"); | |
1441 | return -EFAULT; | |
1442 | } | |
1443 | if (unlikely(vq->log_used)) { | |
1444 | /* Log used index update. */ | |
1445 | log_write(vq->log_base, | |
1446 | vq->log_addr + offsetof(struct vring_used, idx), | |
1447 | sizeof vq->used->idx); | |
1448 | if (vq->log_ctx) | |
1449 | eventfd_signal(vq->log_ctx, 1); | |
1450 | } | |
1451 | return r; | |
1452 | } | |
1453 | ||
8ea8cf89 | 1454 | static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
3a4d5c94 | 1455 | { |
8ea8cf89 MT |
1456 | __u16 old, new, event; |
1457 | bool v; | |
0d499356 MT |
1458 | /* Flush out used index updates. This is paired |
1459 | * with the barrier that the Guest executes when enabling | |
1460 | * interrupts. */ | |
1461 | smp_mb(); | |
1462 | ||
8ea8cf89 MT |
1463 | if (vhost_has_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY) && |
1464 | unlikely(vq->avail_idx == vq->last_avail_idx)) | |
1465 | return true; | |
1466 | ||
1467 | if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { | |
1468 | __u16 flags; | |
1469 | if (__get_user(flags, &vq->avail->flags)) { | |
1470 | vq_err(vq, "Failed to get flags"); | |
1471 | return true; | |
1472 | } | |
1473 | return !(flags & VRING_AVAIL_F_NO_INTERRUPT); | |
3a4d5c94 | 1474 | } |
8ea8cf89 MT |
1475 | old = vq->signalled_used; |
1476 | v = vq->signalled_used_valid; | |
1477 | new = vq->signalled_used = vq->last_used_idx; | |
1478 | vq->signalled_used_valid = true; | |
3a4d5c94 | 1479 | |
8ea8cf89 MT |
1480 | if (unlikely(!v)) |
1481 | return true; | |
3a4d5c94 | 1482 | |
8ea8cf89 MT |
1483 | if (get_user(event, vhost_used_event(vq))) { |
1484 | vq_err(vq, "Failed to get used event idx"); | |
1485 | return true; | |
1486 | } | |
1487 | return vring_need_event(event, new, old); | |
1488 | } | |
1489 | ||
1490 | /* This actually signals the guest, using eventfd. */ | |
1491 | void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq) | |
1492 | { | |
3a4d5c94 | 1493 | /* Signal the Guest tell them we used something up. */ |
8ea8cf89 | 1494 | if (vq->call_ctx && vhost_notify(dev, vq)) |
3a4d5c94 MT |
1495 | eventfd_signal(vq->call_ctx, 1); |
1496 | } | |
1497 | ||
1498 | /* And here's the combo meal deal. Supersize me! */ | |
1499 | void vhost_add_used_and_signal(struct vhost_dev *dev, | |
1500 | struct vhost_virtqueue *vq, | |
1501 | unsigned int head, int len) | |
1502 | { | |
1503 | vhost_add_used(vq, head, len); | |
1504 | vhost_signal(dev, vq); | |
1505 | } | |
1506 | ||
8dd014ad DS |
1507 | /* multi-buffer version of vhost_add_used_and_signal */ |
1508 | void vhost_add_used_and_signal_n(struct vhost_dev *dev, | |
1509 | struct vhost_virtqueue *vq, | |
1510 | struct vring_used_elem *heads, unsigned count) | |
1511 | { | |
1512 | vhost_add_used_n(vq, heads, count); | |
1513 | vhost_signal(dev, vq); | |
1514 | } | |
1515 | ||
3a4d5c94 | 1516 | /* OK, now we need to know about added descriptors. */ |
8ea8cf89 | 1517 | bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
3a4d5c94 MT |
1518 | { |
1519 | u16 avail_idx; | |
1520 | int r; | |
d47effe1 | 1521 | |
3a4d5c94 MT |
1522 | if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY)) |
1523 | return false; | |
1524 | vq->used_flags &= ~VRING_USED_F_NO_NOTIFY; | |
8ea8cf89 | 1525 | if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { |
2723feaa | 1526 | r = vhost_update_used_flags(vq); |
8ea8cf89 MT |
1527 | if (r) { |
1528 | vq_err(vq, "Failed to enable notification at %p: %d\n", | |
1529 | &vq->used->flags, r); | |
1530 | return false; | |
1531 | } | |
1532 | } else { | |
2723feaa | 1533 | r = vhost_update_avail_event(vq, vq->avail_idx); |
8ea8cf89 MT |
1534 | if (r) { |
1535 | vq_err(vq, "Failed to update avail event index at %p: %d\n", | |
1536 | vhost_avail_event(vq), r); | |
1537 | return false; | |
1538 | } | |
1539 | } | |
3a4d5c94 MT |
1540 | /* They could have slipped one in as we were doing that: make |
1541 | * sure it's written, then check again. */ | |
5659338c | 1542 | smp_mb(); |
8b7347aa | 1543 | r = __get_user(avail_idx, &vq->avail->idx); |
3a4d5c94 MT |
1544 | if (r) { |
1545 | vq_err(vq, "Failed to check avail idx at %p: %d\n", | |
1546 | &vq->avail->idx, r); | |
1547 | return false; | |
1548 | } | |
1549 | ||
8dd014ad | 1550 | return avail_idx != vq->avail_idx; |
3a4d5c94 MT |
1551 | } |
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 | } |
bab632d6 MT |
1568 | |
1569 | static void vhost_zerocopy_done_signal(struct kref *kref) | |
1570 | { | |
1571 | struct vhost_ubuf_ref *ubufs = container_of(kref, struct vhost_ubuf_ref, | |
1572 | kref); | |
1573 | wake_up(&ubufs->wait); | |
1574 | } | |
1575 | ||
1576 | struct vhost_ubuf_ref *vhost_ubuf_alloc(struct vhost_virtqueue *vq, | |
1577 | bool zcopy) | |
1578 | { | |
1579 | struct vhost_ubuf_ref *ubufs; | |
1580 | /* No zero copy backend? Nothing to count. */ | |
1581 | if (!zcopy) | |
1582 | return NULL; | |
1583 | ubufs = kmalloc(sizeof *ubufs, GFP_KERNEL); | |
1584 | if (!ubufs) | |
1585 | return ERR_PTR(-ENOMEM); | |
1586 | kref_init(&ubufs->kref); | |
bab632d6 MT |
1587 | init_waitqueue_head(&ubufs->wait); |
1588 | ubufs->vq = vq; | |
1589 | return ubufs; | |
1590 | } | |
1591 | ||
1592 | void vhost_ubuf_put(struct vhost_ubuf_ref *ubufs) | |
1593 | { | |
1594 | kref_put(&ubufs->kref, vhost_zerocopy_done_signal); | |
1595 | } | |
1596 | ||
1597 | void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *ubufs) | |
1598 | { | |
1599 | kref_put(&ubufs->kref, vhost_zerocopy_done_signal); | |
1600 | wait_event(ubufs->wait, !atomic_read(&ubufs->kref.refcount)); | |
1601 | kfree(ubufs); | |
1602 | } | |
1603 | ||
ca8f4fb2 | 1604 | void vhost_zerocopy_callback(struct ubuf_info *ubuf) |
bab632d6 | 1605 | { |
ca8f4fb2 | 1606 | struct vhost_ubuf_ref *ubufs = ubuf->ctx; |
bab632d6 MT |
1607 | struct vhost_virtqueue *vq = ubufs->vq; |
1608 | ||
c70aa540 | 1609 | vhost_poll_queue(&vq->poll); |
bab632d6 MT |
1610 | /* set len = 1 to mark this desc buffers done DMA */ |
1611 | vq->heads[ubuf->desc].len = VHOST_DMA_DONE_LEN; | |
1612 | kref_put(&ubufs->kref, vhost_zerocopy_done_signal); | |
1613 | } |