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 | ||
163049ae | 67 | void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn) |
87d6a412 MT |
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 | ||
163049ae | 140 | void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work) |
3a4d5c94 | 141 | { |
c23f3445 TH |
142 | unsigned long flags; |
143 | ||
144 | spin_lock_irqsave(&dev->work_lock, flags); | |
145 | if (list_empty(&work->node)) { | |
146 | list_add_tail(&work->node, &dev->work_list); | |
147 | work->queue_seq++; | |
148 | wake_up_process(dev->worker); | |
149 | } | |
150 | spin_unlock_irqrestore(&dev->work_lock, flags); | |
3a4d5c94 MT |
151 | } |
152 | ||
87d6a412 MT |
153 | void vhost_poll_queue(struct vhost_poll *poll) |
154 | { | |
155 | vhost_work_queue(poll->dev, &poll->work); | |
156 | } | |
157 | ||
3a4d5c94 MT |
158 | static void vhost_vq_reset(struct vhost_dev *dev, |
159 | struct vhost_virtqueue *vq) | |
160 | { | |
161 | vq->num = 1; | |
162 | vq->desc = NULL; | |
163 | vq->avail = NULL; | |
164 | vq->used = NULL; | |
165 | vq->last_avail_idx = 0; | |
166 | vq->avail_idx = 0; | |
167 | vq->last_used_idx = 0; | |
8ea8cf89 MT |
168 | vq->signalled_used = 0; |
169 | vq->signalled_used_valid = false; | |
3a4d5c94 | 170 | vq->used_flags = 0; |
3a4d5c94 MT |
171 | vq->log_used = false; |
172 | vq->log_addr = -1ull; | |
8dd014ad DS |
173 | vq->vhost_hlen = 0; |
174 | vq->sock_hlen = 0; | |
3a4d5c94 MT |
175 | vq->private_data = NULL; |
176 | vq->log_base = NULL; | |
177 | vq->error_ctx = NULL; | |
178 | vq->error = NULL; | |
179 | vq->kick = NULL; | |
180 | vq->call_ctx = NULL; | |
181 | vq->call = NULL; | |
73a99f08 | 182 | vq->log_ctx = NULL; |
bab632d6 MT |
183 | vq->upend_idx = 0; |
184 | vq->done_idx = 0; | |
185 | vq->ubufs = NULL; | |
3a4d5c94 MT |
186 | } |
187 | ||
c23f3445 TH |
188 | static int vhost_worker(void *data) |
189 | { | |
190 | struct vhost_dev *dev = data; | |
191 | struct vhost_work *work = NULL; | |
192 | unsigned uninitialized_var(seq); | |
d7ffde35 | 193 | mm_segment_t oldfs = get_fs(); |
c23f3445 | 194 | |
d7ffde35 | 195 | set_fs(USER_DS); |
64e1c807 MT |
196 | use_mm(dev->mm); |
197 | ||
c23f3445 TH |
198 | for (;;) { |
199 | /* mb paired w/ kthread_stop */ | |
200 | set_current_state(TASK_INTERRUPTIBLE); | |
201 | ||
202 | spin_lock_irq(&dev->work_lock); | |
203 | if (work) { | |
204 | work->done_seq = seq; | |
205 | if (work->flushing) | |
206 | wake_up_all(&work->done); | |
207 | } | |
208 | ||
209 | if (kthread_should_stop()) { | |
210 | spin_unlock_irq(&dev->work_lock); | |
211 | __set_current_state(TASK_RUNNING); | |
64e1c807 | 212 | break; |
c23f3445 TH |
213 | } |
214 | if (!list_empty(&dev->work_list)) { | |
215 | work = list_first_entry(&dev->work_list, | |
216 | struct vhost_work, node); | |
217 | list_del_init(&work->node); | |
218 | seq = work->queue_seq; | |
219 | } else | |
220 | work = NULL; | |
221 | spin_unlock_irq(&dev->work_lock); | |
222 | ||
223 | if (work) { | |
224 | __set_current_state(TASK_RUNNING); | |
225 | work->fn(work); | |
d550dda1 NHE |
226 | if (need_resched()) |
227 | schedule(); | |
c23f3445 TH |
228 | } else |
229 | schedule(); | |
230 | ||
231 | } | |
64e1c807 | 232 | unuse_mm(dev->mm); |
d7ffde35 | 233 | set_fs(oldfs); |
64e1c807 | 234 | return 0; |
c23f3445 TH |
235 | } |
236 | ||
bab632d6 MT |
237 | static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq) |
238 | { | |
239 | kfree(vq->indirect); | |
240 | vq->indirect = NULL; | |
241 | kfree(vq->log); | |
242 | vq->log = NULL; | |
243 | kfree(vq->heads); | |
244 | vq->heads = NULL; | |
245 | kfree(vq->ubuf_info); | |
246 | vq->ubuf_info = NULL; | |
247 | } | |
248 | ||
249 | void vhost_enable_zcopy(int vq) | |
250 | { | |
251 | vhost_zcopy_mask |= 0x1 << vq; | |
252 | } | |
253 | ||
e0e9b406 JW |
254 | /* Helper to allocate iovec buffers for all vqs. */ |
255 | static long vhost_dev_alloc_iovecs(struct vhost_dev *dev) | |
256 | { | |
257 | int i; | |
bab632d6 | 258 | bool zcopy; |
d47effe1 | 259 | |
e0e9b406 JW |
260 | for (i = 0; i < dev->nvqs; ++i) { |
261 | dev->vqs[i].indirect = kmalloc(sizeof *dev->vqs[i].indirect * | |
262 | UIO_MAXIOV, GFP_KERNEL); | |
263 | dev->vqs[i].log = kmalloc(sizeof *dev->vqs[i].log * UIO_MAXIOV, | |
264 | GFP_KERNEL); | |
265 | dev->vqs[i].heads = kmalloc(sizeof *dev->vqs[i].heads * | |
266 | UIO_MAXIOV, GFP_KERNEL); | |
bab632d6 MT |
267 | zcopy = vhost_zcopy_mask & (0x1 << i); |
268 | if (zcopy) | |
269 | dev->vqs[i].ubuf_info = | |
270 | kmalloc(sizeof *dev->vqs[i].ubuf_info * | |
271 | UIO_MAXIOV, GFP_KERNEL); | |
e0e9b406 | 272 | if (!dev->vqs[i].indirect || !dev->vqs[i].log || |
bab632d6 MT |
273 | !dev->vqs[i].heads || |
274 | (zcopy && !dev->vqs[i].ubuf_info)) | |
e0e9b406 JW |
275 | goto err_nomem; |
276 | } | |
277 | return 0; | |
d47effe1 | 278 | |
e0e9b406 | 279 | err_nomem: |
bab632d6 MT |
280 | for (; i >= 0; --i) |
281 | vhost_vq_free_iovecs(&dev->vqs[i]); | |
e0e9b406 JW |
282 | return -ENOMEM; |
283 | } | |
284 | ||
285 | static void vhost_dev_free_iovecs(struct vhost_dev *dev) | |
286 | { | |
287 | int i; | |
d47effe1 | 288 | |
bab632d6 MT |
289 | for (i = 0; i < dev->nvqs; ++i) |
290 | vhost_vq_free_iovecs(&dev->vqs[i]); | |
e0e9b406 JW |
291 | } |
292 | ||
3a4d5c94 MT |
293 | long vhost_dev_init(struct vhost_dev *dev, |
294 | struct vhost_virtqueue *vqs, int nvqs) | |
295 | { | |
296 | int i; | |
c23f3445 | 297 | |
3a4d5c94 MT |
298 | dev->vqs = vqs; |
299 | dev->nvqs = nvqs; | |
300 | mutex_init(&dev->mutex); | |
301 | dev->log_ctx = NULL; | |
302 | dev->log_file = NULL; | |
303 | dev->memory = NULL; | |
304 | dev->mm = NULL; | |
c23f3445 TH |
305 | spin_lock_init(&dev->work_lock); |
306 | INIT_LIST_HEAD(&dev->work_list); | |
307 | dev->worker = NULL; | |
3a4d5c94 MT |
308 | |
309 | for (i = 0; i < dev->nvqs; ++i) { | |
e0e9b406 JW |
310 | dev->vqs[i].log = NULL; |
311 | dev->vqs[i].indirect = NULL; | |
312 | dev->vqs[i].heads = NULL; | |
bab632d6 | 313 | dev->vqs[i].ubuf_info = NULL; |
3a4d5c94 MT |
314 | dev->vqs[i].dev = dev; |
315 | mutex_init(&dev->vqs[i].mutex); | |
316 | vhost_vq_reset(dev, dev->vqs + i); | |
317 | if (dev->vqs[i].handle_kick) | |
318 | vhost_poll_init(&dev->vqs[i].poll, | |
c23f3445 | 319 | dev->vqs[i].handle_kick, POLLIN, dev); |
3a4d5c94 | 320 | } |
c23f3445 | 321 | |
3a4d5c94 MT |
322 | return 0; |
323 | } | |
324 | ||
325 | /* Caller should have device mutex */ | |
326 | long vhost_dev_check_owner(struct vhost_dev *dev) | |
327 | { | |
328 | /* Are you the owner? If not, I don't think you mean to do that */ | |
329 | return dev->mm == current->mm ? 0 : -EPERM; | |
330 | } | |
331 | ||
87d6a412 | 332 | struct vhost_attach_cgroups_struct { |
d47effe1 KK |
333 | struct vhost_work work; |
334 | struct task_struct *owner; | |
335 | int ret; | |
87d6a412 MT |
336 | }; |
337 | ||
338 | static void vhost_attach_cgroups_work(struct vhost_work *work) | |
339 | { | |
d47effe1 KK |
340 | struct vhost_attach_cgroups_struct *s; |
341 | ||
342 | s = container_of(work, struct vhost_attach_cgroups_struct, work); | |
343 | s->ret = cgroup_attach_task_all(s->owner, current); | |
87d6a412 MT |
344 | } |
345 | ||
346 | static int vhost_attach_cgroups(struct vhost_dev *dev) | |
347 | { | |
d47effe1 KK |
348 | struct vhost_attach_cgroups_struct attach; |
349 | ||
350 | attach.owner = current; | |
351 | vhost_work_init(&attach.work, vhost_attach_cgroups_work); | |
352 | vhost_work_queue(dev, &attach.work); | |
353 | vhost_work_flush(dev, &attach.work); | |
354 | return attach.ret; | |
87d6a412 MT |
355 | } |
356 | ||
3a4d5c94 MT |
357 | /* Caller should have device mutex */ |
358 | static long vhost_dev_set_owner(struct vhost_dev *dev) | |
359 | { | |
c23f3445 TH |
360 | struct task_struct *worker; |
361 | int err; | |
d47effe1 | 362 | |
3a4d5c94 | 363 | /* Is there an owner already? */ |
c23f3445 TH |
364 | if (dev->mm) { |
365 | err = -EBUSY; | |
366 | goto err_mm; | |
367 | } | |
d47effe1 | 368 | |
3a4d5c94 MT |
369 | /* No owner, become one */ |
370 | dev->mm = get_task_mm(current); | |
c23f3445 TH |
371 | worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid); |
372 | if (IS_ERR(worker)) { | |
373 | err = PTR_ERR(worker); | |
374 | goto err_worker; | |
375 | } | |
376 | ||
377 | dev->worker = worker; | |
87d6a412 MT |
378 | wake_up_process(worker); /* avoid contributing to loadavg */ |
379 | ||
380 | err = vhost_attach_cgroups(dev); | |
9e3d1957 MT |
381 | if (err) |
382 | goto err_cgroup; | |
c23f3445 | 383 | |
e0e9b406 JW |
384 | err = vhost_dev_alloc_iovecs(dev); |
385 | if (err) | |
386 | goto err_cgroup; | |
387 | ||
3a4d5c94 | 388 | return 0; |
9e3d1957 MT |
389 | err_cgroup: |
390 | kthread_stop(worker); | |
615cc221 | 391 | dev->worker = NULL; |
c23f3445 TH |
392 | err_worker: |
393 | if (dev->mm) | |
394 | mmput(dev->mm); | |
395 | dev->mm = NULL; | |
396 | err_mm: | |
397 | return err; | |
3a4d5c94 MT |
398 | } |
399 | ||
400 | /* Caller should have device mutex */ | |
401 | long vhost_dev_reset_owner(struct vhost_dev *dev) | |
402 | { | |
403 | struct vhost_memory *memory; | |
404 | ||
405 | /* Restore memory to default empty mapping. */ | |
406 | memory = kmalloc(offsetof(struct vhost_memory, regions), GFP_KERNEL); | |
407 | if (!memory) | |
408 | return -ENOMEM; | |
409 | ||
ea5d4046 | 410 | vhost_dev_cleanup(dev, true); |
3a4d5c94 MT |
411 | |
412 | memory->nregions = 0; | |
28457ee6 | 413 | RCU_INIT_POINTER(dev->memory, memory); |
3a4d5c94 MT |
414 | return 0; |
415 | } | |
416 | ||
bab632d6 MT |
417 | /* In case of DMA done not in order in lower device driver for some reason. |
418 | * upend_idx is used to track end of used idx, done_idx is used to track head | |
419 | * of used idx. Once lower device DMA done contiguously, we will signal KVM | |
420 | * guest used idx. | |
421 | */ | |
422 | int vhost_zerocopy_signal_used(struct vhost_virtqueue *vq) | |
423 | { | |
424 | int i; | |
425 | int j = 0; | |
426 | ||
427 | for (i = vq->done_idx; i != vq->upend_idx; i = (i + 1) % UIO_MAXIOV) { | |
428 | if ((vq->heads[i].len == VHOST_DMA_DONE_LEN)) { | |
429 | vq->heads[i].len = VHOST_DMA_CLEAR_LEN; | |
430 | vhost_add_used_and_signal(vq->dev, vq, | |
431 | vq->heads[i].id, 0); | |
432 | ++j; | |
433 | } else | |
434 | break; | |
435 | } | |
436 | if (j) | |
437 | vq->done_idx = i; | |
438 | return j; | |
439 | } | |
440 | ||
ea5d4046 MT |
441 | /* Caller should have device mutex if and only if locked is set */ |
442 | void vhost_dev_cleanup(struct vhost_dev *dev, bool locked) | |
3a4d5c94 MT |
443 | { |
444 | int i; | |
d47effe1 | 445 | |
3a4d5c94 MT |
446 | for (i = 0; i < dev->nvqs; ++i) { |
447 | if (dev->vqs[i].kick && dev->vqs[i].handle_kick) { | |
448 | vhost_poll_stop(&dev->vqs[i].poll); | |
449 | vhost_poll_flush(&dev->vqs[i].poll); | |
450 | } | |
bab632d6 MT |
451 | /* Wait for all lower device DMAs done. */ |
452 | if (dev->vqs[i].ubufs) | |
453 | vhost_ubuf_put_and_wait(dev->vqs[i].ubufs); | |
454 | ||
455 | /* Signal guest as appropriate. */ | |
456 | vhost_zerocopy_signal_used(&dev->vqs[i]); | |
457 | ||
3a4d5c94 MT |
458 | if (dev->vqs[i].error_ctx) |
459 | eventfd_ctx_put(dev->vqs[i].error_ctx); | |
460 | if (dev->vqs[i].error) | |
461 | fput(dev->vqs[i].error); | |
462 | if (dev->vqs[i].kick) | |
463 | fput(dev->vqs[i].kick); | |
464 | if (dev->vqs[i].call_ctx) | |
465 | eventfd_ctx_put(dev->vqs[i].call_ctx); | |
466 | if (dev->vqs[i].call) | |
467 | fput(dev->vqs[i].call); | |
468 | vhost_vq_reset(dev, dev->vqs + i); | |
469 | } | |
e0e9b406 | 470 | vhost_dev_free_iovecs(dev); |
3a4d5c94 MT |
471 | if (dev->log_ctx) |
472 | eventfd_ctx_put(dev->log_ctx); | |
473 | dev->log_ctx = NULL; | |
474 | if (dev->log_file) | |
475 | fput(dev->log_file); | |
476 | dev->log_file = NULL; | |
477 | /* No one will access memory at this point */ | |
28457ee6 | 478 | kfree(rcu_dereference_protected(dev->memory, |
ea5d4046 MT |
479 | locked == |
480 | lockdep_is_held(&dev->mutex))); | |
28457ee6 | 481 | RCU_INIT_POINTER(dev->memory, NULL); |
c23f3445 | 482 | WARN_ON(!list_empty(&dev->work_list)); |
78b620ce ED |
483 | if (dev->worker) { |
484 | kthread_stop(dev->worker); | |
485 | dev->worker = NULL; | |
486 | } | |
533a19b4 MT |
487 | if (dev->mm) |
488 | mmput(dev->mm); | |
489 | dev->mm = NULL; | |
3a4d5c94 MT |
490 | } |
491 | ||
492 | static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz) | |
493 | { | |
494 | u64 a = addr / VHOST_PAGE_SIZE / 8; | |
d47effe1 | 495 | |
3a4d5c94 MT |
496 | /* Make sure 64 bit math will not overflow. */ |
497 | if (a > ULONG_MAX - (unsigned long)log_base || | |
498 | a + (unsigned long)log_base > ULONG_MAX) | |
6d97e55f | 499 | return 0; |
3a4d5c94 MT |
500 | |
501 | return access_ok(VERIFY_WRITE, log_base + a, | |
502 | (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8); | |
503 | } | |
504 | ||
505 | /* Caller should have vq mutex and device mutex. */ | |
506 | static int vq_memory_access_ok(void __user *log_base, struct vhost_memory *mem, | |
507 | int log_all) | |
508 | { | |
509 | int i; | |
179b284e | 510 | |
f8322fbe MT |
511 | if (!mem) |
512 | return 0; | |
179b284e | 513 | |
3a4d5c94 MT |
514 | for (i = 0; i < mem->nregions; ++i) { |
515 | struct vhost_memory_region *m = mem->regions + i; | |
516 | unsigned long a = m->userspace_addr; | |
517 | if (m->memory_size > ULONG_MAX) | |
518 | return 0; | |
519 | else if (!access_ok(VERIFY_WRITE, (void __user *)a, | |
520 | m->memory_size)) | |
521 | return 0; | |
522 | else if (log_all && !log_access_ok(log_base, | |
523 | m->guest_phys_addr, | |
524 | m->memory_size)) | |
525 | return 0; | |
526 | } | |
527 | return 1; | |
528 | } | |
529 | ||
530 | /* Can we switch to this memory table? */ | |
531 | /* Caller should have device mutex but not vq mutex */ | |
532 | static int memory_access_ok(struct vhost_dev *d, struct vhost_memory *mem, | |
533 | int log_all) | |
534 | { | |
535 | int i; | |
d47effe1 | 536 | |
3a4d5c94 MT |
537 | for (i = 0; i < d->nvqs; ++i) { |
538 | int ok; | |
539 | mutex_lock(&d->vqs[i].mutex); | |
540 | /* If ring is inactive, will check when it's enabled. */ | |
541 | if (d->vqs[i].private_data) | |
542 | ok = vq_memory_access_ok(d->vqs[i].log_base, mem, | |
543 | log_all); | |
544 | else | |
545 | ok = 1; | |
546 | mutex_unlock(&d->vqs[i].mutex); | |
547 | if (!ok) | |
548 | return 0; | |
549 | } | |
550 | return 1; | |
551 | } | |
552 | ||
8ea8cf89 | 553 | static int vq_access_ok(struct vhost_dev *d, unsigned int num, |
3a4d5c94 MT |
554 | struct vring_desc __user *desc, |
555 | struct vring_avail __user *avail, | |
556 | struct vring_used __user *used) | |
557 | { | |
8ea8cf89 | 558 | size_t s = vhost_has_feature(d, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; |
3a4d5c94 MT |
559 | return access_ok(VERIFY_READ, desc, num * sizeof *desc) && |
560 | access_ok(VERIFY_READ, avail, | |
8ea8cf89 | 561 | sizeof *avail + num * sizeof *avail->ring + s) && |
3a4d5c94 | 562 | access_ok(VERIFY_WRITE, used, |
8ea8cf89 | 563 | sizeof *used + num * sizeof *used->ring + s); |
3a4d5c94 MT |
564 | } |
565 | ||
566 | /* Can we log writes? */ | |
567 | /* Caller should have device mutex but not vq mutex */ | |
568 | int vhost_log_access_ok(struct vhost_dev *dev) | |
569 | { | |
28457ee6 AB |
570 | struct vhost_memory *mp; |
571 | ||
572 | mp = rcu_dereference_protected(dev->memory, | |
573 | lockdep_is_held(&dev->mutex)); | |
574 | return memory_access_ok(dev, mp, 1); | |
3a4d5c94 MT |
575 | } |
576 | ||
577 | /* Verify access for write logging. */ | |
578 | /* Caller should have vq mutex and device mutex */ | |
8ea8cf89 MT |
579 | static int vq_log_access_ok(struct vhost_dev *d, struct vhost_virtqueue *vq, |
580 | void __user *log_base) | |
3a4d5c94 | 581 | { |
28457ee6 | 582 | struct vhost_memory *mp; |
8ea8cf89 | 583 | size_t s = vhost_has_feature(d, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; |
28457ee6 AB |
584 | |
585 | mp = rcu_dereference_protected(vq->dev->memory, | |
586 | lockdep_is_held(&vq->mutex)); | |
587 | return vq_memory_access_ok(log_base, mp, | |
3a4d5c94 MT |
588 | vhost_has_feature(vq->dev, VHOST_F_LOG_ALL)) && |
589 | (!vq->log_used || log_access_ok(log_base, vq->log_addr, | |
590 | sizeof *vq->used + | |
8ea8cf89 | 591 | vq->num * sizeof *vq->used->ring + s)); |
3a4d5c94 MT |
592 | } |
593 | ||
594 | /* Can we start vq? */ | |
595 | /* Caller should have vq mutex and device mutex */ | |
596 | int vhost_vq_access_ok(struct vhost_virtqueue *vq) | |
597 | { | |
8ea8cf89 MT |
598 | return vq_access_ok(vq->dev, vq->num, vq->desc, vq->avail, vq->used) && |
599 | vq_log_access_ok(vq->dev, vq, vq->log_base); | |
3a4d5c94 MT |
600 | } |
601 | ||
602 | static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) | |
603 | { | |
604 | struct vhost_memory mem, *newmem, *oldmem; | |
605 | unsigned long size = offsetof(struct vhost_memory, regions); | |
d47effe1 | 606 | |
7ad9c9d2 TY |
607 | if (copy_from_user(&mem, m, size)) |
608 | return -EFAULT; | |
3a4d5c94 MT |
609 | if (mem.padding) |
610 | return -EOPNOTSUPP; | |
611 | if (mem.nregions > VHOST_MEMORY_MAX_NREGIONS) | |
612 | return -E2BIG; | |
613 | newmem = kmalloc(size + mem.nregions * sizeof *m->regions, GFP_KERNEL); | |
614 | if (!newmem) | |
615 | return -ENOMEM; | |
616 | ||
617 | memcpy(newmem, &mem, size); | |
7ad9c9d2 TY |
618 | if (copy_from_user(newmem->regions, m->regions, |
619 | mem.nregions * sizeof *m->regions)) { | |
3a4d5c94 | 620 | kfree(newmem); |
7ad9c9d2 | 621 | return -EFAULT; |
3a4d5c94 MT |
622 | } |
623 | ||
d47effe1 KK |
624 | if (!memory_access_ok(d, newmem, |
625 | vhost_has_feature(d, VHOST_F_LOG_ALL))) { | |
a02c3789 | 626 | kfree(newmem); |
3a4d5c94 | 627 | return -EFAULT; |
a02c3789 | 628 | } |
28457ee6 AB |
629 | oldmem = rcu_dereference_protected(d->memory, |
630 | lockdep_is_held(&d->mutex)); | |
3a4d5c94 MT |
631 | rcu_assign_pointer(d->memory, newmem); |
632 | synchronize_rcu(); | |
633 | kfree(oldmem); | |
634 | return 0; | |
635 | } | |
636 | ||
3a4d5c94 MT |
637 | static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp) |
638 | { | |
cecb46f1 AV |
639 | struct file *eventfp, *filep = NULL; |
640 | bool pollstart = false, pollstop = false; | |
3a4d5c94 MT |
641 | struct eventfd_ctx *ctx = NULL; |
642 | u32 __user *idxp = argp; | |
643 | struct vhost_virtqueue *vq; | |
644 | struct vhost_vring_state s; | |
645 | struct vhost_vring_file f; | |
646 | struct vhost_vring_addr a; | |
647 | u32 idx; | |
648 | long r; | |
649 | ||
650 | r = get_user(idx, idxp); | |
651 | if (r < 0) | |
652 | return r; | |
0f3d9a17 | 653 | if (idx >= d->nvqs) |
3a4d5c94 MT |
654 | return -ENOBUFS; |
655 | ||
656 | vq = d->vqs + idx; | |
657 | ||
658 | mutex_lock(&vq->mutex); | |
659 | ||
660 | switch (ioctl) { | |
661 | case VHOST_SET_VRING_NUM: | |
662 | /* Resizing ring with an active backend? | |
663 | * You don't want to do that. */ | |
664 | if (vq->private_data) { | |
665 | r = -EBUSY; | |
666 | break; | |
667 | } | |
7ad9c9d2 TY |
668 | if (copy_from_user(&s, argp, sizeof s)) { |
669 | r = -EFAULT; | |
3a4d5c94 | 670 | break; |
7ad9c9d2 | 671 | } |
3a4d5c94 MT |
672 | if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) { |
673 | r = -EINVAL; | |
674 | break; | |
675 | } | |
676 | vq->num = s.num; | |
677 | break; | |
678 | case VHOST_SET_VRING_BASE: | |
679 | /* Moving base with an active backend? | |
680 | * You don't want to do that. */ | |
681 | if (vq->private_data) { | |
682 | r = -EBUSY; | |
683 | break; | |
684 | } | |
7ad9c9d2 TY |
685 | if (copy_from_user(&s, argp, sizeof s)) { |
686 | r = -EFAULT; | |
3a4d5c94 | 687 | break; |
7ad9c9d2 | 688 | } |
3a4d5c94 MT |
689 | if (s.num > 0xffff) { |
690 | r = -EINVAL; | |
691 | break; | |
692 | } | |
693 | vq->last_avail_idx = s.num; | |
694 | /* Forget the cached index value. */ | |
695 | vq->avail_idx = vq->last_avail_idx; | |
696 | break; | |
697 | case VHOST_GET_VRING_BASE: | |
698 | s.index = idx; | |
699 | s.num = vq->last_avail_idx; | |
7ad9c9d2 TY |
700 | if (copy_to_user(argp, &s, sizeof s)) |
701 | r = -EFAULT; | |
3a4d5c94 MT |
702 | break; |
703 | case VHOST_SET_VRING_ADDR: | |
7ad9c9d2 TY |
704 | if (copy_from_user(&a, argp, sizeof a)) { |
705 | r = -EFAULT; | |
3a4d5c94 | 706 | break; |
7ad9c9d2 | 707 | } |
3a4d5c94 MT |
708 | if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) { |
709 | r = -EOPNOTSUPP; | |
710 | break; | |
711 | } | |
712 | /* For 32bit, verify that the top 32bits of the user | |
713 | data are set to zero. */ | |
714 | if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr || | |
715 | (u64)(unsigned long)a.used_user_addr != a.used_user_addr || | |
716 | (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) { | |
717 | r = -EFAULT; | |
718 | break; | |
719 | } | |
720 | if ((a.avail_user_addr & (sizeof *vq->avail->ring - 1)) || | |
721 | (a.used_user_addr & (sizeof *vq->used->ring - 1)) || | |
722 | (a.log_guest_addr & (sizeof *vq->used->ring - 1))) { | |
723 | r = -EINVAL; | |
724 | break; | |
725 | } | |
726 | ||
727 | /* We only verify access here if backend is configured. | |
728 | * If it is not, we don't as size might not have been setup. | |
729 | * We will verify when backend is configured. */ | |
730 | if (vq->private_data) { | |
8ea8cf89 | 731 | if (!vq_access_ok(d, vq->num, |
3a4d5c94 MT |
732 | (void __user *)(unsigned long)a.desc_user_addr, |
733 | (void __user *)(unsigned long)a.avail_user_addr, | |
734 | (void __user *)(unsigned long)a.used_user_addr)) { | |
735 | r = -EINVAL; | |
736 | break; | |
737 | } | |
738 | ||
739 | /* Also validate log access for used ring if enabled. */ | |
740 | if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) && | |
741 | !log_access_ok(vq->log_base, a.log_guest_addr, | |
742 | sizeof *vq->used + | |
743 | vq->num * sizeof *vq->used->ring)) { | |
744 | r = -EINVAL; | |
745 | break; | |
746 | } | |
747 | } | |
748 | ||
3a4d5c94 MT |
749 | vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG)); |
750 | vq->desc = (void __user *)(unsigned long)a.desc_user_addr; | |
751 | vq->avail = (void __user *)(unsigned long)a.avail_user_addr; | |
752 | vq->log_addr = a.log_guest_addr; | |
753 | vq->used = (void __user *)(unsigned long)a.used_user_addr; | |
754 | break; | |
755 | case VHOST_SET_VRING_KICK: | |
7ad9c9d2 TY |
756 | if (copy_from_user(&f, argp, sizeof f)) { |
757 | r = -EFAULT; | |
3a4d5c94 | 758 | break; |
7ad9c9d2 | 759 | } |
3a4d5c94 | 760 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
761 | if (IS_ERR(eventfp)) { |
762 | r = PTR_ERR(eventfp); | |
763 | break; | |
764 | } | |
3a4d5c94 | 765 | if (eventfp != vq->kick) { |
cecb46f1 AV |
766 | pollstop = (filep = vq->kick) != NULL; |
767 | pollstart = (vq->kick = eventfp) != NULL; | |
3a4d5c94 MT |
768 | } else |
769 | filep = eventfp; | |
770 | break; | |
771 | case VHOST_SET_VRING_CALL: | |
7ad9c9d2 TY |
772 | if (copy_from_user(&f, argp, sizeof f)) { |
773 | r = -EFAULT; | |
3a4d5c94 | 774 | break; |
7ad9c9d2 | 775 | } |
3a4d5c94 | 776 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
777 | if (IS_ERR(eventfp)) { |
778 | r = PTR_ERR(eventfp); | |
779 | break; | |
780 | } | |
3a4d5c94 MT |
781 | if (eventfp != vq->call) { |
782 | filep = vq->call; | |
783 | ctx = vq->call_ctx; | |
784 | vq->call = eventfp; | |
785 | vq->call_ctx = eventfp ? | |
786 | eventfd_ctx_fileget(eventfp) : NULL; | |
787 | } else | |
788 | filep = eventfp; | |
789 | break; | |
790 | case VHOST_SET_VRING_ERR: | |
7ad9c9d2 TY |
791 | if (copy_from_user(&f, argp, sizeof f)) { |
792 | r = -EFAULT; | |
3a4d5c94 | 793 | break; |
7ad9c9d2 | 794 | } |
3a4d5c94 | 795 | eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); |
535297a6 MT |
796 | if (IS_ERR(eventfp)) { |
797 | r = PTR_ERR(eventfp); | |
798 | break; | |
799 | } | |
3a4d5c94 MT |
800 | if (eventfp != vq->error) { |
801 | filep = vq->error; | |
802 | vq->error = eventfp; | |
803 | ctx = vq->error_ctx; | |
804 | vq->error_ctx = eventfp ? | |
805 | eventfd_ctx_fileget(eventfp) : NULL; | |
806 | } else | |
807 | filep = eventfp; | |
808 | break; | |
809 | default: | |
810 | r = -ENOIOCTLCMD; | |
811 | } | |
812 | ||
813 | if (pollstop && vq->handle_kick) | |
814 | vhost_poll_stop(&vq->poll); | |
815 | ||
816 | if (ctx) | |
817 | eventfd_ctx_put(ctx); | |
818 | if (filep) | |
819 | fput(filep); | |
820 | ||
821 | if (pollstart && vq->handle_kick) | |
822 | vhost_poll_start(&vq->poll, vq->kick); | |
823 | ||
824 | mutex_unlock(&vq->mutex); | |
825 | ||
826 | if (pollstop && vq->handle_kick) | |
827 | vhost_poll_flush(&vq->poll); | |
828 | return r; | |
829 | } | |
830 | ||
831 | /* Caller must have device mutex */ | |
832 | long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, unsigned long arg) | |
833 | { | |
834 | void __user *argp = (void __user *)arg; | |
835 | struct file *eventfp, *filep = NULL; | |
836 | struct eventfd_ctx *ctx = NULL; | |
837 | u64 p; | |
838 | long r; | |
839 | int i, fd; | |
840 | ||
841 | /* If you are not the owner, you can become one */ | |
842 | if (ioctl == VHOST_SET_OWNER) { | |
843 | r = vhost_dev_set_owner(d); | |
844 | goto done; | |
845 | } | |
846 | ||
847 | /* You must be the owner to do anything else */ | |
848 | r = vhost_dev_check_owner(d); | |
849 | if (r) | |
850 | goto done; | |
851 | ||
852 | switch (ioctl) { | |
853 | case VHOST_SET_MEM_TABLE: | |
854 | r = vhost_set_memory(d, argp); | |
855 | break; | |
856 | case VHOST_SET_LOG_BASE: | |
7ad9c9d2 TY |
857 | if (copy_from_user(&p, argp, sizeof p)) { |
858 | r = -EFAULT; | |
3a4d5c94 | 859 | break; |
7ad9c9d2 | 860 | } |
3a4d5c94 MT |
861 | if ((u64)(unsigned long)p != p) { |
862 | r = -EFAULT; | |
863 | break; | |
864 | } | |
865 | for (i = 0; i < d->nvqs; ++i) { | |
866 | struct vhost_virtqueue *vq; | |
867 | void __user *base = (void __user *)(unsigned long)p; | |
868 | vq = d->vqs + i; | |
869 | mutex_lock(&vq->mutex); | |
870 | /* If ring is inactive, will check when it's enabled. */ | |
8ea8cf89 | 871 | if (vq->private_data && !vq_log_access_ok(d, vq, base)) |
3a4d5c94 MT |
872 | r = -EFAULT; |
873 | else | |
874 | vq->log_base = base; | |
875 | mutex_unlock(&vq->mutex); | |
876 | } | |
877 | break; | |
878 | case VHOST_SET_LOG_FD: | |
879 | r = get_user(fd, (int __user *)argp); | |
880 | if (r < 0) | |
881 | break; | |
882 | eventfp = fd == -1 ? NULL : eventfd_fget(fd); | |
883 | if (IS_ERR(eventfp)) { | |
884 | r = PTR_ERR(eventfp); | |
885 | break; | |
886 | } | |
887 | if (eventfp != d->log_file) { | |
888 | filep = d->log_file; | |
889 | ctx = d->log_ctx; | |
890 | d->log_ctx = eventfp ? | |
891 | eventfd_ctx_fileget(eventfp) : NULL; | |
892 | } else | |
893 | filep = eventfp; | |
894 | for (i = 0; i < d->nvqs; ++i) { | |
895 | mutex_lock(&d->vqs[i].mutex); | |
896 | d->vqs[i].log_ctx = d->log_ctx; | |
897 | mutex_unlock(&d->vqs[i].mutex); | |
898 | } | |
899 | if (ctx) | |
900 | eventfd_ctx_put(ctx); | |
901 | if (filep) | |
902 | fput(filep); | |
903 | break; | |
904 | default: | |
905 | r = vhost_set_vring(d, ioctl, argp); | |
906 | break; | |
907 | } | |
908 | done: | |
909 | return r; | |
910 | } | |
911 | ||
912 | static const struct vhost_memory_region *find_region(struct vhost_memory *mem, | |
913 | __u64 addr, __u32 len) | |
914 | { | |
915 | struct vhost_memory_region *reg; | |
916 | int i; | |
d47effe1 | 917 | |
3a4d5c94 MT |
918 | /* linear search is not brilliant, but we really have on the order of 6 |
919 | * regions in practice */ | |
920 | for (i = 0; i < mem->nregions; ++i) { | |
921 | reg = mem->regions + i; | |
922 | if (reg->guest_phys_addr <= addr && | |
923 | reg->guest_phys_addr + reg->memory_size - 1 >= addr) | |
924 | return reg; | |
925 | } | |
926 | return NULL; | |
927 | } | |
928 | ||
929 | /* TODO: This is really inefficient. We need something like get_user() | |
930 | * (instruction directly accesses the data, with an exception table entry | |
931 | * returning -EFAULT). See Documentation/x86/exception-tables.txt. | |
932 | */ | |
933 | static int set_bit_to_user(int nr, void __user *addr) | |
934 | { | |
935 | unsigned long log = (unsigned long)addr; | |
936 | struct page *page; | |
937 | void *base; | |
938 | int bit = nr + (log % PAGE_SIZE) * 8; | |
939 | int r; | |
d47effe1 | 940 | |
3a4d5c94 | 941 | r = get_user_pages_fast(log, 1, 1, &page); |
d6db3f5c | 942 | if (r < 0) |
3a4d5c94 | 943 | return r; |
d6db3f5c | 944 | BUG_ON(r != 1); |
c6daa7ff | 945 | base = kmap_atomic(page); |
3a4d5c94 | 946 | set_bit(bit, base); |
c6daa7ff | 947 | kunmap_atomic(base); |
3a4d5c94 MT |
948 | set_page_dirty_lock(page); |
949 | put_page(page); | |
950 | return 0; | |
951 | } | |
952 | ||
953 | static int log_write(void __user *log_base, | |
954 | u64 write_address, u64 write_length) | |
955 | { | |
28831ee6 | 956 | u64 write_page = write_address / VHOST_PAGE_SIZE; |
3a4d5c94 | 957 | int r; |
d47effe1 | 958 | |
3a4d5c94 MT |
959 | if (!write_length) |
960 | return 0; | |
3bf9be40 | 961 | write_length += write_address % VHOST_PAGE_SIZE; |
3a4d5c94 MT |
962 | for (;;) { |
963 | u64 base = (u64)(unsigned long)log_base; | |
28831ee6 MT |
964 | u64 log = base + write_page / 8; |
965 | int bit = write_page % 8; | |
3a4d5c94 MT |
966 | if ((u64)(unsigned long)log != log) |
967 | return -EFAULT; | |
968 | r = set_bit_to_user(bit, (void __user *)(unsigned long)log); | |
969 | if (r < 0) | |
970 | return r; | |
971 | if (write_length <= VHOST_PAGE_SIZE) | |
972 | break; | |
973 | write_length -= VHOST_PAGE_SIZE; | |
28831ee6 | 974 | write_page += 1; |
3a4d5c94 MT |
975 | } |
976 | return r; | |
977 | } | |
978 | ||
979 | int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, | |
980 | unsigned int log_num, u64 len) | |
981 | { | |
982 | int i, r; | |
983 | ||
984 | /* Make sure data written is seen before log. */ | |
5659338c | 985 | smp_wmb(); |
3a4d5c94 MT |
986 | for (i = 0; i < log_num; ++i) { |
987 | u64 l = min(log[i].len, len); | |
988 | r = log_write(vq->log_base, log[i].addr, l); | |
989 | if (r < 0) | |
990 | return r; | |
991 | len -= l; | |
5786aee8 MT |
992 | if (!len) { |
993 | if (vq->log_ctx) | |
994 | eventfd_signal(vq->log_ctx, 1); | |
3a4d5c94 | 995 | return 0; |
5786aee8 | 996 | } |
3a4d5c94 | 997 | } |
3a4d5c94 MT |
998 | /* Length written exceeds what we have stored. This is a bug. */ |
999 | BUG(); | |
1000 | return 0; | |
1001 | } | |
1002 | ||
2723feaa JW |
1003 | static int vhost_update_used_flags(struct vhost_virtqueue *vq) |
1004 | { | |
1005 | void __user *used; | |
b834226b | 1006 | if (__put_user(vq->used_flags, &vq->used->flags) < 0) |
2723feaa JW |
1007 | return -EFAULT; |
1008 | if (unlikely(vq->log_used)) { | |
1009 | /* Make sure the flag is seen before log. */ | |
1010 | smp_wmb(); | |
1011 | /* Log used flag write. */ | |
1012 | used = &vq->used->flags; | |
1013 | log_write(vq->log_base, vq->log_addr + | |
1014 | (used - (void __user *)vq->used), | |
1015 | sizeof vq->used->flags); | |
1016 | if (vq->log_ctx) | |
1017 | eventfd_signal(vq->log_ctx, 1); | |
1018 | } | |
1019 | return 0; | |
1020 | } | |
1021 | ||
1022 | static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event) | |
1023 | { | |
b834226b | 1024 | if (__put_user(vq->avail_idx, vhost_avail_event(vq))) |
2723feaa JW |
1025 | return -EFAULT; |
1026 | if (unlikely(vq->log_used)) { | |
1027 | void __user *used; | |
1028 | /* Make sure the event is seen before log. */ | |
1029 | smp_wmb(); | |
1030 | /* Log avail event write */ | |
1031 | used = vhost_avail_event(vq); | |
1032 | log_write(vq->log_base, vq->log_addr + | |
1033 | (used - (void __user *)vq->used), | |
1034 | sizeof *vhost_avail_event(vq)); | |
1035 | if (vq->log_ctx) | |
1036 | eventfd_signal(vq->log_ctx, 1); | |
1037 | } | |
1038 | return 0; | |
1039 | } | |
1040 | ||
1041 | int vhost_init_used(struct vhost_virtqueue *vq) | |
1042 | { | |
1043 | int r; | |
1044 | if (!vq->private_data) | |
1045 | return 0; | |
1046 | ||
1047 | r = vhost_update_used_flags(vq); | |
1048 | if (r) | |
1049 | return r; | |
1050 | vq->signalled_used_valid = false; | |
1051 | return get_user(vq->last_used_idx, &vq->used->idx); | |
1052 | } | |
1053 | ||
a8d3782f CH |
1054 | static int translate_desc(struct vhost_dev *dev, u64 addr, u32 len, |
1055 | struct iovec iov[], int iov_size) | |
3a4d5c94 MT |
1056 | { |
1057 | const struct vhost_memory_region *reg; | |
1058 | struct vhost_memory *mem; | |
1059 | struct iovec *_iov; | |
1060 | u64 s = 0; | |
1061 | int ret = 0; | |
1062 | ||
1063 | rcu_read_lock(); | |
1064 | ||
1065 | mem = rcu_dereference(dev->memory); | |
1066 | while ((u64)len > s) { | |
1067 | u64 size; | |
7b3384fc | 1068 | if (unlikely(ret >= iov_size)) { |
3a4d5c94 MT |
1069 | ret = -ENOBUFS; |
1070 | break; | |
1071 | } | |
1072 | reg = find_region(mem, addr, len); | |
7b3384fc | 1073 | if (unlikely(!reg)) { |
3a4d5c94 MT |
1074 | ret = -EFAULT; |
1075 | break; | |
1076 | } | |
1077 | _iov = iov + ret; | |
1078 | size = reg->memory_size - addr + reg->guest_phys_addr; | |
1079 | _iov->iov_len = min((u64)len, size); | |
a8d3782f | 1080 | _iov->iov_base = (void __user *)(unsigned long) |
3a4d5c94 MT |
1081 | (reg->userspace_addr + addr - reg->guest_phys_addr); |
1082 | s += size; | |
1083 | addr += size; | |
1084 | ++ret; | |
1085 | } | |
1086 | ||
1087 | rcu_read_unlock(); | |
1088 | return ret; | |
1089 | } | |
1090 | ||
1091 | /* Each buffer in the virtqueues is actually a chain of descriptors. This | |
1092 | * function returns the next descriptor in the chain, | |
1093 | * or -1U if we're at the end. */ | |
1094 | static unsigned next_desc(struct vring_desc *desc) | |
1095 | { | |
1096 | unsigned int next; | |
1097 | ||
1098 | /* If this descriptor says it doesn't chain, we're done. */ | |
1099 | if (!(desc->flags & VRING_DESC_F_NEXT)) | |
1100 | return -1U; | |
1101 | ||
1102 | /* Check they're not leading us off end of descriptors. */ | |
1103 | next = desc->next; | |
1104 | /* Make sure compiler knows to grab that: we don't want it changing! */ | |
1105 | /* We will use the result as an index in an array, so most | |
1106 | * architectures only need a compiler barrier here. */ | |
1107 | read_barrier_depends(); | |
1108 | ||
1109 | return next; | |
1110 | } | |
1111 | ||
7b3384fc MT |
1112 | static int get_indirect(struct vhost_dev *dev, struct vhost_virtqueue *vq, |
1113 | struct iovec iov[], unsigned int iov_size, | |
1114 | unsigned int *out_num, unsigned int *in_num, | |
1115 | struct vhost_log *log, unsigned int *log_num, | |
1116 | struct vring_desc *indirect) | |
3a4d5c94 MT |
1117 | { |
1118 | struct vring_desc desc; | |
1119 | unsigned int i = 0, count, found = 0; | |
1120 | int ret; | |
1121 | ||
1122 | /* Sanity check */ | |
7b3384fc | 1123 | if (unlikely(indirect->len % sizeof desc)) { |
3a4d5c94 MT |
1124 | vq_err(vq, "Invalid length in indirect descriptor: " |
1125 | "len 0x%llx not multiple of 0x%zx\n", | |
1126 | (unsigned long long)indirect->len, | |
1127 | sizeof desc); | |
1128 | return -EINVAL; | |
1129 | } | |
1130 | ||
1131 | ret = translate_desc(dev, indirect->addr, indirect->len, vq->indirect, | |
e0e9b406 | 1132 | UIO_MAXIOV); |
7b3384fc | 1133 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1134 | vq_err(vq, "Translation failure %d in indirect.\n", ret); |
1135 | return ret; | |
1136 | } | |
1137 | ||
1138 | /* We will use the result as an address to read from, so most | |
1139 | * architectures only need a compiler barrier here. */ | |
1140 | read_barrier_depends(); | |
1141 | ||
1142 | count = indirect->len / sizeof desc; | |
1143 | /* Buffers are chained via a 16 bit next field, so | |
1144 | * we can have at most 2^16 of these. */ | |
7b3384fc | 1145 | if (unlikely(count > USHRT_MAX + 1)) { |
3a4d5c94 MT |
1146 | vq_err(vq, "Indirect buffer length too big: %d\n", |
1147 | indirect->len); | |
1148 | return -E2BIG; | |
1149 | } | |
1150 | ||
1151 | do { | |
1152 | unsigned iov_count = *in_num + *out_num; | |
7b3384fc | 1153 | if (unlikely(++found > count)) { |
3a4d5c94 MT |
1154 | vq_err(vq, "Loop detected: last one at %u " |
1155 | "indirect size %u\n", | |
1156 | i, count); | |
1157 | return -EINVAL; | |
1158 | } | |
d47effe1 KK |
1159 | if (unlikely(memcpy_fromiovec((unsigned char *)&desc, |
1160 | vq->indirect, sizeof desc))) { | |
3a4d5c94 MT |
1161 | vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n", |
1162 | i, (size_t)indirect->addr + i * sizeof desc); | |
1163 | return -EINVAL; | |
1164 | } | |
7b3384fc | 1165 | if (unlikely(desc.flags & VRING_DESC_F_INDIRECT)) { |
3a4d5c94 MT |
1166 | vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n", |
1167 | i, (size_t)indirect->addr + i * sizeof desc); | |
1168 | return -EINVAL; | |
1169 | } | |
1170 | ||
1171 | ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, | |
1172 | iov_size - iov_count); | |
7b3384fc | 1173 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1174 | vq_err(vq, "Translation failure %d indirect idx %d\n", |
1175 | ret, i); | |
1176 | return ret; | |
1177 | } | |
1178 | /* If this is an input descriptor, increment that count. */ | |
1179 | if (desc.flags & VRING_DESC_F_WRITE) { | |
1180 | *in_num += ret; | |
1181 | if (unlikely(log)) { | |
1182 | log[*log_num].addr = desc.addr; | |
1183 | log[*log_num].len = desc.len; | |
1184 | ++*log_num; | |
1185 | } | |
1186 | } else { | |
1187 | /* If it's an output descriptor, they're all supposed | |
1188 | * to come before any input descriptors. */ | |
7b3384fc | 1189 | if (unlikely(*in_num)) { |
3a4d5c94 MT |
1190 | vq_err(vq, "Indirect descriptor " |
1191 | "has out after in: idx %d\n", i); | |
1192 | return -EINVAL; | |
1193 | } | |
1194 | *out_num += ret; | |
1195 | } | |
1196 | } while ((i = next_desc(&desc)) != -1); | |
1197 | return 0; | |
1198 | } | |
1199 | ||
1200 | /* This looks in the virtqueue and for the first available buffer, and converts | |
1201 | * it to an iovec for convenient access. Since descriptors consist of some | |
1202 | * number of output then some number of input descriptors, it's actually two | |
1203 | * iovecs, but we pack them into one and note how many of each there were. | |
1204 | * | |
d5675bd2 MT |
1205 | * This function returns the descriptor number found, or vq->num (which is |
1206 | * never a valid descriptor number) if none was found. A negative code is | |
1207 | * returned on error. */ | |
1208 | int vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq, | |
1209 | struct iovec iov[], unsigned int iov_size, | |
1210 | unsigned int *out_num, unsigned int *in_num, | |
1211 | struct vhost_log *log, unsigned int *log_num) | |
3a4d5c94 MT |
1212 | { |
1213 | struct vring_desc desc; | |
1214 | unsigned int i, head, found = 0; | |
1215 | u16 last_avail_idx; | |
1216 | int ret; | |
1217 | ||
1218 | /* Check it isn't doing very strange things with descriptor numbers. */ | |
1219 | last_avail_idx = vq->last_avail_idx; | |
8b7347aa | 1220 | if (unlikely(__get_user(vq->avail_idx, &vq->avail->idx))) { |
3a4d5c94 MT |
1221 | vq_err(vq, "Failed to access avail idx at %p\n", |
1222 | &vq->avail->idx); | |
d5675bd2 | 1223 | return -EFAULT; |
3a4d5c94 MT |
1224 | } |
1225 | ||
7b3384fc | 1226 | if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) { |
3a4d5c94 MT |
1227 | vq_err(vq, "Guest moved used index from %u to %u", |
1228 | last_avail_idx, vq->avail_idx); | |
d5675bd2 | 1229 | return -EFAULT; |
3a4d5c94 MT |
1230 | } |
1231 | ||
1232 | /* If there's nothing new since last we looked, return invalid. */ | |
1233 | if (vq->avail_idx == last_avail_idx) | |
1234 | return vq->num; | |
1235 | ||
1236 | /* Only get avail ring entries after they have been exposed by guest. */ | |
5659338c | 1237 | smp_rmb(); |
3a4d5c94 MT |
1238 | |
1239 | /* Grab the next descriptor number they're advertising, and increment | |
1240 | * the index we've seen. */ | |
8b7347aa MT |
1241 | if (unlikely(__get_user(head, |
1242 | &vq->avail->ring[last_avail_idx % vq->num]))) { | |
3a4d5c94 MT |
1243 | vq_err(vq, "Failed to read head: idx %d address %p\n", |
1244 | last_avail_idx, | |
1245 | &vq->avail->ring[last_avail_idx % vq->num]); | |
d5675bd2 | 1246 | return -EFAULT; |
3a4d5c94 MT |
1247 | } |
1248 | ||
1249 | /* If their number is silly, that's an error. */ | |
7b3384fc | 1250 | if (unlikely(head >= vq->num)) { |
3a4d5c94 MT |
1251 | vq_err(vq, "Guest says index %u > %u is available", |
1252 | head, vq->num); | |
d5675bd2 | 1253 | return -EINVAL; |
3a4d5c94 MT |
1254 | } |
1255 | ||
1256 | /* When we start there are none of either input nor output. */ | |
1257 | *out_num = *in_num = 0; | |
1258 | if (unlikely(log)) | |
1259 | *log_num = 0; | |
1260 | ||
1261 | i = head; | |
1262 | do { | |
1263 | unsigned iov_count = *in_num + *out_num; | |
7b3384fc | 1264 | if (unlikely(i >= vq->num)) { |
3a4d5c94 MT |
1265 | vq_err(vq, "Desc index is %u > %u, head = %u", |
1266 | i, vq->num, head); | |
d5675bd2 | 1267 | return -EINVAL; |
3a4d5c94 | 1268 | } |
7b3384fc | 1269 | if (unlikely(++found > vq->num)) { |
3a4d5c94 MT |
1270 | vq_err(vq, "Loop detected: last one at %u " |
1271 | "vq size %u head %u\n", | |
1272 | i, vq->num, head); | |
d5675bd2 | 1273 | return -EINVAL; |
3a4d5c94 | 1274 | } |
fcc042a2 | 1275 | ret = __copy_from_user(&desc, vq->desc + i, sizeof desc); |
7b3384fc | 1276 | if (unlikely(ret)) { |
3a4d5c94 MT |
1277 | vq_err(vq, "Failed to get descriptor: idx %d addr %p\n", |
1278 | i, vq->desc + i); | |
d5675bd2 | 1279 | return -EFAULT; |
3a4d5c94 MT |
1280 | } |
1281 | if (desc.flags & VRING_DESC_F_INDIRECT) { | |
1282 | ret = get_indirect(dev, vq, iov, iov_size, | |
1283 | out_num, in_num, | |
1284 | log, log_num, &desc); | |
7b3384fc | 1285 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1286 | vq_err(vq, "Failure detected " |
1287 | "in indirect descriptor at idx %d\n", i); | |
d5675bd2 | 1288 | return ret; |
3a4d5c94 MT |
1289 | } |
1290 | continue; | |
1291 | } | |
1292 | ||
1293 | ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, | |
1294 | iov_size - iov_count); | |
7b3384fc | 1295 | if (unlikely(ret < 0)) { |
3a4d5c94 MT |
1296 | vq_err(vq, "Translation failure %d descriptor idx %d\n", |
1297 | ret, i); | |
d5675bd2 | 1298 | return ret; |
3a4d5c94 MT |
1299 | } |
1300 | if (desc.flags & VRING_DESC_F_WRITE) { | |
1301 | /* If this is an input descriptor, | |
1302 | * increment that count. */ | |
1303 | *in_num += ret; | |
1304 | if (unlikely(log)) { | |
1305 | log[*log_num].addr = desc.addr; | |
1306 | log[*log_num].len = desc.len; | |
1307 | ++*log_num; | |
1308 | } | |
1309 | } else { | |
1310 | /* If it's an output descriptor, they're all supposed | |
1311 | * to come before any input descriptors. */ | |
7b3384fc | 1312 | if (unlikely(*in_num)) { |
3a4d5c94 MT |
1313 | vq_err(vq, "Descriptor has out after in: " |
1314 | "idx %d\n", i); | |
d5675bd2 | 1315 | return -EINVAL; |
3a4d5c94 MT |
1316 | } |
1317 | *out_num += ret; | |
1318 | } | |
1319 | } while ((i = next_desc(&desc)) != -1); | |
1320 | ||
1321 | /* On success, increment avail index. */ | |
1322 | vq->last_avail_idx++; | |
8ea8cf89 MT |
1323 | |
1324 | /* Assume notifications from guest are disabled at this point, | |
1325 | * if they aren't we would need to update avail_event index. */ | |
1326 | BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY)); | |
3a4d5c94 MT |
1327 | return head; |
1328 | } | |
1329 | ||
1330 | /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */ | |
8dd014ad | 1331 | void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n) |
3a4d5c94 | 1332 | { |
8dd014ad | 1333 | vq->last_avail_idx -= n; |
3a4d5c94 MT |
1334 | } |
1335 | ||
1336 | /* After we've used one of their buffers, we tell them about it. We'll then | |
1337 | * want to notify the guest, using eventfd. */ | |
1338 | int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len) | |
1339 | { | |
a8d3782f | 1340 | struct vring_used_elem __user *used; |
3a4d5c94 MT |
1341 | |
1342 | /* The virtqueue contains a ring of used buffers. Get a pointer to the | |
1343 | * next entry in that used ring. */ | |
1344 | used = &vq->used->ring[vq->last_used_idx % vq->num]; | |
8b7347aa | 1345 | if (__put_user(head, &used->id)) { |
3a4d5c94 MT |
1346 | vq_err(vq, "Failed to write used id"); |
1347 | return -EFAULT; | |
1348 | } | |
8b7347aa | 1349 | if (__put_user(len, &used->len)) { |
3a4d5c94 MT |
1350 | vq_err(vq, "Failed to write used len"); |
1351 | return -EFAULT; | |
1352 | } | |
1353 | /* Make sure buffer is written before we update index. */ | |
5659338c | 1354 | smp_wmb(); |
8b7347aa | 1355 | if (__put_user(vq->last_used_idx + 1, &vq->used->idx)) { |
3a4d5c94 MT |
1356 | vq_err(vq, "Failed to increment used idx"); |
1357 | return -EFAULT; | |
1358 | } | |
1359 | if (unlikely(vq->log_used)) { | |
1360 | /* Make sure data is seen before log. */ | |
5659338c | 1361 | smp_wmb(); |
86e9424d MT |
1362 | /* Log used ring entry write. */ |
1363 | log_write(vq->log_base, | |
a8d3782f CH |
1364 | vq->log_addr + |
1365 | ((void __user *)used - (void __user *)vq->used), | |
86e9424d MT |
1366 | sizeof *used); |
1367 | /* Log used index update. */ | |
1368 | log_write(vq->log_base, | |
1369 | vq->log_addr + offsetof(struct vring_used, idx), | |
1370 | sizeof vq->used->idx); | |
3a4d5c94 MT |
1371 | if (vq->log_ctx) |
1372 | eventfd_signal(vq->log_ctx, 1); | |
1373 | } | |
1374 | vq->last_used_idx++; | |
8ea8cf89 MT |
1375 | /* If the driver never bothers to signal in a very long while, |
1376 | * used index might wrap around. If that happens, invalidate | |
1377 | * signalled_used index we stored. TODO: make sure driver | |
1378 | * signals at least once in 2^16 and remove this. */ | |
1379 | if (unlikely(vq->last_used_idx == vq->signalled_used)) | |
1380 | vq->signalled_used_valid = false; | |
3a4d5c94 MT |
1381 | return 0; |
1382 | } | |
1383 | ||
8dd014ad DS |
1384 | static int __vhost_add_used_n(struct vhost_virtqueue *vq, |
1385 | struct vring_used_elem *heads, | |
1386 | unsigned count) | |
1387 | { | |
1388 | struct vring_used_elem __user *used; | |
8ea8cf89 | 1389 | u16 old, new; |
8dd014ad DS |
1390 | int start; |
1391 | ||
1392 | start = vq->last_used_idx % vq->num; | |
1393 | used = vq->used->ring + start; | |
dfe5ac5b | 1394 | if (__copy_to_user(used, heads, count * sizeof *used)) { |
8dd014ad DS |
1395 | vq_err(vq, "Failed to write used"); |
1396 | return -EFAULT; | |
1397 | } | |
1398 | if (unlikely(vq->log_used)) { | |
1399 | /* Make sure data is seen before log. */ | |
1400 | smp_wmb(); | |
1401 | /* Log used ring entry write. */ | |
1402 | log_write(vq->log_base, | |
1403 | vq->log_addr + | |
1404 | ((void __user *)used - (void __user *)vq->used), | |
1405 | count * sizeof *used); | |
1406 | } | |
8ea8cf89 MT |
1407 | old = vq->last_used_idx; |
1408 | new = (vq->last_used_idx += count); | |
1409 | /* If the driver never bothers to signal in a very long while, | |
1410 | * used index might wrap around. If that happens, invalidate | |
1411 | * signalled_used index we stored. TODO: make sure driver | |
1412 | * signals at least once in 2^16 and remove this. */ | |
1413 | if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old))) | |
1414 | vq->signalled_used_valid = false; | |
8dd014ad DS |
1415 | return 0; |
1416 | } | |
1417 | ||
1418 | /* After we've used one of their buffers, we tell them about it. We'll then | |
1419 | * want to notify the guest, using eventfd. */ | |
1420 | int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads, | |
1421 | unsigned count) | |
1422 | { | |
1423 | int start, n, r; | |
1424 | ||
1425 | start = vq->last_used_idx % vq->num; | |
1426 | n = vq->num - start; | |
1427 | if (n < count) { | |
1428 | r = __vhost_add_used_n(vq, heads, n); | |
1429 | if (r < 0) | |
1430 | return r; | |
1431 | heads += n; | |
1432 | count -= n; | |
1433 | } | |
1434 | r = __vhost_add_used_n(vq, heads, count); | |
1435 | ||
1436 | /* Make sure buffer is written before we update index. */ | |
1437 | smp_wmb(); | |
1438 | if (put_user(vq->last_used_idx, &vq->used->idx)) { | |
1439 | vq_err(vq, "Failed to increment used idx"); | |
1440 | return -EFAULT; | |
1441 | } | |
1442 | if (unlikely(vq->log_used)) { | |
1443 | /* Log used index update. */ | |
1444 | log_write(vq->log_base, | |
1445 | vq->log_addr + offsetof(struct vring_used, idx), | |
1446 | sizeof vq->used->idx); | |
1447 | if (vq->log_ctx) | |
1448 | eventfd_signal(vq->log_ctx, 1); | |
1449 | } | |
1450 | return r; | |
1451 | } | |
1452 | ||
8ea8cf89 | 1453 | static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
3a4d5c94 | 1454 | { |
8ea8cf89 MT |
1455 | __u16 old, new, event; |
1456 | bool v; | |
0d499356 MT |
1457 | /* Flush out used index updates. This is paired |
1458 | * with the barrier that the Guest executes when enabling | |
1459 | * interrupts. */ | |
1460 | smp_mb(); | |
1461 | ||
8ea8cf89 MT |
1462 | if (vhost_has_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY) && |
1463 | unlikely(vq->avail_idx == vq->last_avail_idx)) | |
1464 | return true; | |
1465 | ||
1466 | if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { | |
1467 | __u16 flags; | |
1468 | if (__get_user(flags, &vq->avail->flags)) { | |
1469 | vq_err(vq, "Failed to get flags"); | |
1470 | return true; | |
1471 | } | |
1472 | return !(flags & VRING_AVAIL_F_NO_INTERRUPT); | |
3a4d5c94 | 1473 | } |
8ea8cf89 MT |
1474 | old = vq->signalled_used; |
1475 | v = vq->signalled_used_valid; | |
1476 | new = vq->signalled_used = vq->last_used_idx; | |
1477 | vq->signalled_used_valid = true; | |
3a4d5c94 | 1478 | |
8ea8cf89 MT |
1479 | if (unlikely(!v)) |
1480 | return true; | |
3a4d5c94 | 1481 | |
8ea8cf89 MT |
1482 | if (get_user(event, vhost_used_event(vq))) { |
1483 | vq_err(vq, "Failed to get used event idx"); | |
1484 | return true; | |
1485 | } | |
1486 | return vring_need_event(event, new, old); | |
1487 | } | |
1488 | ||
1489 | /* This actually signals the guest, using eventfd. */ | |
1490 | void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq) | |
1491 | { | |
3a4d5c94 | 1492 | /* Signal the Guest tell them we used something up. */ |
8ea8cf89 | 1493 | if (vq->call_ctx && vhost_notify(dev, vq)) |
3a4d5c94 MT |
1494 | eventfd_signal(vq->call_ctx, 1); |
1495 | } | |
1496 | ||
1497 | /* And here's the combo meal deal. Supersize me! */ | |
1498 | void vhost_add_used_and_signal(struct vhost_dev *dev, | |
1499 | struct vhost_virtqueue *vq, | |
1500 | unsigned int head, int len) | |
1501 | { | |
1502 | vhost_add_used(vq, head, len); | |
1503 | vhost_signal(dev, vq); | |
1504 | } | |
1505 | ||
8dd014ad DS |
1506 | /* multi-buffer version of vhost_add_used_and_signal */ |
1507 | void vhost_add_used_and_signal_n(struct vhost_dev *dev, | |
1508 | struct vhost_virtqueue *vq, | |
1509 | struct vring_used_elem *heads, unsigned count) | |
1510 | { | |
1511 | vhost_add_used_n(vq, heads, count); | |
1512 | vhost_signal(dev, vq); | |
1513 | } | |
1514 | ||
3a4d5c94 | 1515 | /* OK, now we need to know about added descriptors. */ |
8ea8cf89 | 1516 | bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
3a4d5c94 MT |
1517 | { |
1518 | u16 avail_idx; | |
1519 | int r; | |
d47effe1 | 1520 | |
3a4d5c94 MT |
1521 | if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY)) |
1522 | return false; | |
1523 | vq->used_flags &= ~VRING_USED_F_NO_NOTIFY; | |
8ea8cf89 | 1524 | if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { |
2723feaa | 1525 | r = vhost_update_used_flags(vq); |
8ea8cf89 MT |
1526 | if (r) { |
1527 | vq_err(vq, "Failed to enable notification at %p: %d\n", | |
1528 | &vq->used->flags, r); | |
1529 | return false; | |
1530 | } | |
1531 | } else { | |
2723feaa | 1532 | r = vhost_update_avail_event(vq, vq->avail_idx); |
8ea8cf89 MT |
1533 | if (r) { |
1534 | vq_err(vq, "Failed to update avail event index at %p: %d\n", | |
1535 | vhost_avail_event(vq), r); | |
1536 | return false; | |
1537 | } | |
1538 | } | |
3a4d5c94 MT |
1539 | /* They could have slipped one in as we were doing that: make |
1540 | * sure it's written, then check again. */ | |
5659338c | 1541 | smp_mb(); |
8b7347aa | 1542 | r = __get_user(avail_idx, &vq->avail->idx); |
3a4d5c94 MT |
1543 | if (r) { |
1544 | vq_err(vq, "Failed to check avail idx at %p: %d\n", | |
1545 | &vq->avail->idx, r); | |
1546 | return false; | |
1547 | } | |
1548 | ||
8dd014ad | 1549 | return avail_idx != vq->avail_idx; |
3a4d5c94 MT |
1550 | } |
1551 | ||
1552 | /* We don't need to be notified again. */ | |
8ea8cf89 | 1553 | void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
3a4d5c94 MT |
1554 | { |
1555 | int r; | |
d47effe1 | 1556 | |
3a4d5c94 MT |
1557 | if (vq->used_flags & VRING_USED_F_NO_NOTIFY) |
1558 | return; | |
1559 | vq->used_flags |= VRING_USED_F_NO_NOTIFY; | |
8ea8cf89 | 1560 | if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { |
2723feaa | 1561 | r = vhost_update_used_flags(vq); |
8ea8cf89 MT |
1562 | if (r) |
1563 | vq_err(vq, "Failed to enable notification at %p: %d\n", | |
1564 | &vq->used->flags, r); | |
1565 | } | |
3a4d5c94 | 1566 | } |
bab632d6 MT |
1567 | |
1568 | static void vhost_zerocopy_done_signal(struct kref *kref) | |
1569 | { | |
1570 | struct vhost_ubuf_ref *ubufs = container_of(kref, struct vhost_ubuf_ref, | |
1571 | kref); | |
1572 | wake_up(&ubufs->wait); | |
1573 | } | |
1574 | ||
1575 | struct vhost_ubuf_ref *vhost_ubuf_alloc(struct vhost_virtqueue *vq, | |
1576 | bool zcopy) | |
1577 | { | |
1578 | struct vhost_ubuf_ref *ubufs; | |
1579 | /* No zero copy backend? Nothing to count. */ | |
1580 | if (!zcopy) | |
1581 | return NULL; | |
1582 | ubufs = kmalloc(sizeof *ubufs, GFP_KERNEL); | |
1583 | if (!ubufs) | |
1584 | return ERR_PTR(-ENOMEM); | |
1585 | kref_init(&ubufs->kref); | |
bab632d6 MT |
1586 | init_waitqueue_head(&ubufs->wait); |
1587 | ubufs->vq = vq; | |
1588 | return ubufs; | |
1589 | } | |
1590 | ||
1591 | void vhost_ubuf_put(struct vhost_ubuf_ref *ubufs) | |
1592 | { | |
1593 | kref_put(&ubufs->kref, vhost_zerocopy_done_signal); | |
1594 | } | |
1595 | ||
1596 | void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *ubufs) | |
1597 | { | |
1598 | kref_put(&ubufs->kref, vhost_zerocopy_done_signal); | |
1599 | wait_event(ubufs->wait, !atomic_read(&ubufs->kref.refcount)); | |
1600 | kfree(ubufs); | |
1601 | } | |
1602 | ||
ca8f4fb2 | 1603 | void vhost_zerocopy_callback(struct ubuf_info *ubuf) |
bab632d6 | 1604 | { |
ca8f4fb2 | 1605 | struct vhost_ubuf_ref *ubufs = ubuf->ctx; |
bab632d6 MT |
1606 | struct vhost_virtqueue *vq = ubufs->vq; |
1607 | ||
c70aa540 | 1608 | vhost_poll_queue(&vq->poll); |
bab632d6 MT |
1609 | /* set len = 1 to mark this desc buffers done DMA */ |
1610 | vq->heads[ubuf->desc].len = VHOST_DMA_DONE_LEN; | |
1611 | kref_put(&ubufs->kref, vhost_zerocopy_done_signal); | |
1612 | } |