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sctp: walk the list of asoc safely
[linux/fpc-iii.git] / drivers / xen / pvcalls-back.c
blobb1092fbefa6309d2535b17b78979b6f3fa9b2b42
1 /*
2 * (c) 2017 Stefano Stabellini <stefano@aporeto.com>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 */
14
15 #include <linux/inet.h>
16 #include <linux/kthread.h>
17 #include <linux/list.h>
18 #include <linux/radix-tree.h>
19 #include <linux/module.h>
20 #include <linux/semaphore.h>
21 #include <linux/wait.h>
22 #include <net/sock.h>
23 #include <net/inet_common.h>
24 #include <net/inet_connection_sock.h>
25 #include <net/request_sock.h>
26
27 #include <xen/events.h>
28 #include <xen/grant_table.h>
29 #include <xen/xen.h>
30 #include <xen/xenbus.h>
31 #include <xen/interface/io/pvcalls.h>
32
33 #define PVCALLS_VERSIONS "1"
34 #define MAX_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER
35
36 struct pvcalls_back_global {
37 struct list_head frontends;
38 struct semaphore frontends_lock;
39 } pvcalls_back_global;
40
41 /*
42 * Per-frontend data structure. It contains pointers to the command
43 * ring, its event channel, a list of active sockets and a tree of
44 * passive sockets.
45 */
46 struct pvcalls_fedata {
47 struct list_head list;
48 struct xenbus_device *dev;
49 struct xen_pvcalls_sring *sring;
50 struct xen_pvcalls_back_ring ring;
51 int irq;
52 struct list_head socket_mappings;
53 struct radix_tree_root socketpass_mappings;
54 struct semaphore socket_lock;
55 };
56
57 struct pvcalls_ioworker {
58 struct work_struct register_work;
59 struct workqueue_struct *wq;
60 };
61
62 struct sock_mapping {
63 struct list_head list;
64 struct pvcalls_fedata *fedata;
65 struct sockpass_mapping *sockpass;
66 struct socket *sock;
67 uint64_t id;
68 grant_ref_t ref;
69 struct pvcalls_data_intf *ring;
70 void *bytes;
71 struct pvcalls_data data;
72 uint32_t ring_order;
73 int irq;
74 atomic_t read;
75 atomic_t write;
76 atomic_t io;
77 atomic_t release;
78 void (*saved_data_ready)(struct sock *sk);
79 struct pvcalls_ioworker ioworker;
80 };
81
82 struct sockpass_mapping {
83 struct list_head list;
84 struct pvcalls_fedata *fedata;
85 struct socket *sock;
86 uint64_t id;
87 struct xen_pvcalls_request reqcopy;
88 spinlock_t copy_lock;
89 struct workqueue_struct *wq;
90 struct work_struct register_work;
91 void (*saved_data_ready)(struct sock *sk);
92 };
93
94 static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map);
95 static int pvcalls_back_release_active(struct xenbus_device *dev,
96 struct pvcalls_fedata *fedata,
97 struct sock_mapping *map);
98
99 static void pvcalls_conn_back_read(void *opaque)
100 {
101 struct sock_mapping *map = (struct sock_mapping *)opaque;
102 struct msghdr msg;
103 struct kvec vec[2];
104 RING_IDX cons, prod, size, wanted, array_size, masked_prod, masked_cons;
105 int32_t error;
106 struct pvcalls_data_intf *intf = map->ring;
107 struct pvcalls_data *data = &map->data;
108 unsigned long flags;
109 int ret;
110
111 array_size = XEN_FLEX_RING_SIZE(map->ring_order);
112 cons = intf->in_cons;
113 prod = intf->in_prod;
114 error = intf->in_error;
115 /* read the indexes first, then deal with the data */
116 virt_mb();
117
118 if (error)
119 return;
120
121 size = pvcalls_queued(prod, cons, array_size);
122 if (size >= array_size)
123 return;
124 spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags);
125 if (skb_queue_empty(&map->sock->sk->sk_receive_queue)) {
126 atomic_set(&map->read, 0);
127 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock,
128 flags);
129 return;
130 }
131 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags);
132 wanted = array_size - size;
133 masked_prod = pvcalls_mask(prod, array_size);
134 masked_cons = pvcalls_mask(cons, array_size);
135
136 memset(&msg, 0, sizeof(msg));
137 if (masked_prod < masked_cons) {
138 vec[0].iov_base = data->in + masked_prod;
139 vec[0].iov_len = wanted;
140 iov_iter_kvec(&msg.msg_iter, ITER_KVEC|WRITE, vec, 1, wanted);
141 } else {
142 vec[0].iov_base = data->in + masked_prod;
143 vec[0].iov_len = array_size - masked_prod;
144 vec[1].iov_base = data->in;
145 vec[1].iov_len = wanted - vec[0].iov_len;
146 iov_iter_kvec(&msg.msg_iter, ITER_KVEC|WRITE, vec, 2, wanted);
147 }
148
149 atomic_set(&map->read, 0);
150 ret = inet_recvmsg(map->sock, &msg, wanted, MSG_DONTWAIT);
151 WARN_ON(ret > wanted);
152 if (ret == -EAGAIN) /* shouldn't happen */
153 return;
154 if (!ret)
155 ret = -ENOTCONN;
156 spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags);
157 if (ret > 0 && !skb_queue_empty(&map->sock->sk->sk_receive_queue))
158 atomic_inc(&map->read);
159 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags);
160
161 /* write the data, then modify the indexes */
162 virt_wmb();
163 if (ret < 0)
164 intf->in_error = ret;
165 else
166 intf->in_prod = prod + ret;
167 /* update the indexes, then notify the other end */
168 virt_wmb();
169 notify_remote_via_irq(map->irq);
170
171 return;
172 }
173
174 static void pvcalls_conn_back_write(struct sock_mapping *map)
175 {
176 struct pvcalls_data_intf *intf = map->ring;
177 struct pvcalls_data *data = &map->data;
178 struct msghdr msg;
179 struct kvec vec[2];
180 RING_IDX cons, prod, size, array_size;
181 int ret;
182
183 cons = intf->out_cons;
184 prod = intf->out_prod;
185 /* read the indexes before dealing with the data */
186 virt_mb();
187
188 array_size = XEN_FLEX_RING_SIZE(map->ring_order);
189 size = pvcalls_queued(prod, cons, array_size);
190 if (size == 0)
191 return;
192
193 memset(&msg, 0, sizeof(msg));
194 msg.msg_flags |= MSG_DONTWAIT;
195 if (pvcalls_mask(prod, array_size) > pvcalls_mask(cons, array_size)) {
196 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
197 vec[0].iov_len = size;
198 iov_iter_kvec(&msg.msg_iter, ITER_KVEC|READ, vec, 1, size);
199 } else {
200 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
201 vec[0].iov_len = array_size - pvcalls_mask(cons, array_size);
202 vec[1].iov_base = data->out;
203 vec[1].iov_len = size - vec[0].iov_len;
204 iov_iter_kvec(&msg.msg_iter, ITER_KVEC|READ, vec, 2, size);
205 }
206
207 atomic_set(&map->write, 0);
208 ret = inet_sendmsg(map->sock, &msg, size);
209 if (ret == -EAGAIN || (ret >= 0 && ret < size)) {
210 atomic_inc(&map->write);
211 atomic_inc(&map->io);
212 }
213 if (ret == -EAGAIN)
214 return;
215
216 /* write the data, then update the indexes */
217 virt_wmb();
218 if (ret < 0) {
219 intf->out_error = ret;
220 } else {
221 intf->out_error = 0;
222 intf->out_cons = cons + ret;
223 prod = intf->out_prod;
224 }
225 /* update the indexes, then notify the other end */
226 virt_wmb();
227 if (prod != cons + ret)
228 atomic_inc(&map->write);
229 notify_remote_via_irq(map->irq);
230 }
231
232 static void pvcalls_back_ioworker(struct work_struct *work)
233 {
234 struct pvcalls_ioworker *ioworker = container_of(work,
235 struct pvcalls_ioworker, register_work);
236 struct sock_mapping *map = container_of(ioworker, struct sock_mapping,
237 ioworker);
238
239 while (atomic_read(&map->io) > 0) {
240 if (atomic_read(&map->release) > 0) {
241 atomic_set(&map->release, 0);
242 return;
243 }
244
245 if (atomic_read(&map->read) > 0)
246 pvcalls_conn_back_read(map);
247 if (atomic_read(&map->write) > 0)
248 pvcalls_conn_back_write(map);
249
250 atomic_dec(&map->io);
251 }
252 }
253
254 static int pvcalls_back_socket(struct xenbus_device *dev,
255 struct xen_pvcalls_request *req)
256 {
257 struct pvcalls_fedata *fedata;
258 int ret;
259 struct xen_pvcalls_response *rsp;
260
261 fedata = dev_get_drvdata(&dev->dev);
262
263 if (req->u.socket.domain != AF_INET ||
264 req->u.socket.type != SOCK_STREAM ||
265 (req->u.socket.protocol != IPPROTO_IP &&
266 req->u.socket.protocol != AF_INET))
267 ret = -EAFNOSUPPORT;
268 else
269 ret = 0;
270
271 /* leave the actual socket allocation for later */
272
273 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
274 rsp->req_id = req->req_id;
275 rsp->cmd = req->cmd;
276 rsp->u.socket.id = req->u.socket.id;
277 rsp->ret = ret;
278
279 return 0;
280 }
281
282 static void pvcalls_sk_state_change(struct sock *sock)
283 {
284 struct sock_mapping *map = sock->sk_user_data;
285 struct pvcalls_data_intf *intf;
286
287 if (map == NULL)
288 return;
289
290 intf = map->ring;
291 intf->in_error = -ENOTCONN;
292 notify_remote_via_irq(map->irq);
293 }
294
295 static void pvcalls_sk_data_ready(struct sock *sock)
296 {
297 struct sock_mapping *map = sock->sk_user_data;
298 struct pvcalls_ioworker *iow;
299
300 if (map == NULL)
301 return;
302
303 iow = &map->ioworker;
304 atomic_inc(&map->read);
305 atomic_inc(&map->io);
306 queue_work(iow->wq, &iow->register_work);
307 }
308
309 static struct sock_mapping *pvcalls_new_active_socket(
310 struct pvcalls_fedata *fedata,
311 uint64_t id,
312 grant_ref_t ref,
313 uint32_t evtchn,
314 struct socket *sock)
315 {
316 int ret;
317 struct sock_mapping *map;
318 void *page;
319
320 map = kzalloc(sizeof(*map), GFP_KERNEL);
321 if (map == NULL)
322 return NULL;
323
324 map->fedata = fedata;
325 map->sock = sock;
326 map->id = id;
327 map->ref = ref;
328
329 ret = xenbus_map_ring_valloc(fedata->dev, &ref, 1, &page);
330 if (ret < 0)
331 goto out;
332 map->ring = page;
333 map->ring_order = map->ring->ring_order;
334 /* first read the order, then map the data ring */
335 virt_rmb();
336 if (map->ring_order > MAX_RING_ORDER) {
337 pr_warn("%s frontend requested ring_order %u, which is > MAX (%u)\n",
338 __func__, map->ring_order, MAX_RING_ORDER);
339 goto out;
340 }
341 ret = xenbus_map_ring_valloc(fedata->dev, map->ring->ref,
342 (1 << map->ring_order), &page);
343 if (ret < 0)
344 goto out;
345 map->bytes = page;
346
347 ret = bind_interdomain_evtchn_to_irqhandler(fedata->dev->otherend_id,
348 evtchn,
349 pvcalls_back_conn_event,
350 0,
351 "pvcalls-backend",
352 map);
353 if (ret < 0)
354 goto out;
355 map->irq = ret;
356
357 map->data.in = map->bytes;
358 map->data.out = map->bytes + XEN_FLEX_RING_SIZE(map->ring_order);
359
360 map->ioworker.wq = alloc_workqueue("pvcalls_io", WQ_UNBOUND, 1);
361 if (!map->ioworker.wq)
362 goto out;
363 atomic_set(&map->io, 1);
364 INIT_WORK(&map->ioworker.register_work, pvcalls_back_ioworker);
365
366 down(&fedata->socket_lock);
367 list_add_tail(&map->list, &fedata->socket_mappings);
368 up(&fedata->socket_lock);
369
370 write_lock_bh(&map->sock->sk->sk_callback_lock);
371 map->saved_data_ready = map->sock->sk->sk_data_ready;
372 map->sock->sk->sk_user_data = map;
373 map->sock->sk->sk_data_ready = pvcalls_sk_data_ready;
374 map->sock->sk->sk_state_change = pvcalls_sk_state_change;
375 write_unlock_bh(&map->sock->sk->sk_callback_lock);
376
377 return map;
378 out:
379 down(&fedata->socket_lock);
380 list_del(&map->list);
381 pvcalls_back_release_active(fedata->dev, fedata, map);
382 up(&fedata->socket_lock);
383 return NULL;
384 }
385
386 static int pvcalls_back_connect(struct xenbus_device *dev,
387 struct xen_pvcalls_request *req)
388 {
389 struct pvcalls_fedata *fedata;
390 int ret = -EINVAL;
391 struct socket *sock;
392 struct sock_mapping *map;
393 struct xen_pvcalls_response *rsp;
394 struct sockaddr *sa = (struct sockaddr *)&req->u.connect.addr;
395
396 fedata = dev_get_drvdata(&dev->dev);
397
398 if (req->u.connect.len < sizeof(sa->sa_family) ||
399 req->u.connect.len > sizeof(req->u.connect.addr) ||
400 sa->sa_family != AF_INET)
401 goto out;
402
403 ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock);
404 if (ret < 0)
405 goto out;
406 ret = inet_stream_connect(sock, sa, req->u.connect.len, 0);
407 if (ret < 0) {
408 sock_release(sock);
409 goto out;
410 }
411
412 map = pvcalls_new_active_socket(fedata,
413 req->u.connect.id,
414 req->u.connect.ref,
415 req->u.connect.evtchn,
416 sock);
417 if (!map) {
418 ret = -EFAULT;
419 sock_release(sock);
420 }
421
422 out:
423 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
424 rsp->req_id = req->req_id;
425 rsp->cmd = req->cmd;
426 rsp->u.connect.id = req->u.connect.id;
427 rsp->ret = ret;
428
429 return 0;
430 }
431
432 static int pvcalls_back_release_active(struct xenbus_device *dev,
433 struct pvcalls_fedata *fedata,
434 struct sock_mapping *map)
435 {
436 disable_irq(map->irq);
437 if (map->sock->sk != NULL) {
438 write_lock_bh(&map->sock->sk->sk_callback_lock);
439 map->sock->sk->sk_user_data = NULL;
440 map->sock->sk->sk_data_ready = map->saved_data_ready;
441 write_unlock_bh(&map->sock->sk->sk_callback_lock);
442 }
443
444 atomic_set(&map->release, 1);
445 flush_work(&map->ioworker.register_work);
446
447 xenbus_unmap_ring_vfree(dev, map->bytes);
448 xenbus_unmap_ring_vfree(dev, (void *)map->ring);
449 unbind_from_irqhandler(map->irq, map);
450
451 sock_release(map->sock);
452 kfree(map);
453
454 return 0;
455 }
456
457 static int pvcalls_back_release_passive(struct xenbus_device *dev,
458 struct pvcalls_fedata *fedata,
459 struct sockpass_mapping *mappass)
460 {
461 if (mappass->sock->sk != NULL) {
462 write_lock_bh(&mappass->sock->sk->sk_callback_lock);
463 mappass->sock->sk->sk_user_data = NULL;
464 mappass->sock->sk->sk_data_ready = mappass->saved_data_ready;
465 write_unlock_bh(&mappass->sock->sk->sk_callback_lock);
466 }
467 sock_release(mappass->sock);
468 flush_workqueue(mappass->wq);
469 destroy_workqueue(mappass->wq);
470 kfree(mappass);
471
472 return 0;
473 }
474
475 static int pvcalls_back_release(struct xenbus_device *dev,
476 struct xen_pvcalls_request *req)
477 {
478 struct pvcalls_fedata *fedata;
479 struct sock_mapping *map, *n;
480 struct sockpass_mapping *mappass;
481 int ret = 0;
482 struct xen_pvcalls_response *rsp;
483
484 fedata = dev_get_drvdata(&dev->dev);
485
486 down(&fedata->socket_lock);
487 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {
488 if (map->id == req->u.release.id) {
489 list_del(&map->list);
490 up(&fedata->socket_lock);
491 ret = pvcalls_back_release_active(dev, fedata, map);
492 goto out;
493 }
494 }
495 mappass = radix_tree_lookup(&fedata->socketpass_mappings,
496 req->u.release.id);
497 if (mappass != NULL) {
498 radix_tree_delete(&fedata->socketpass_mappings, mappass->id);
499 up(&fedata->socket_lock);
500 ret = pvcalls_back_release_passive(dev, fedata, mappass);
501 } else
502 up(&fedata->socket_lock);
503
504 out:
505 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
506 rsp->req_id = req->req_id;
507 rsp->u.release.id = req->u.release.id;
508 rsp->cmd = req->cmd;
509 rsp->ret = ret;
510 return 0;
511 }
512
513 static void __pvcalls_back_accept(struct work_struct *work)
514 {
515 struct sockpass_mapping *mappass = container_of(
516 work, struct sockpass_mapping, register_work);
517 struct sock_mapping *map;
518 struct pvcalls_ioworker *iow;
519 struct pvcalls_fedata *fedata;
520 struct socket *sock;
521 struct xen_pvcalls_response *rsp;
522 struct xen_pvcalls_request *req;
523 int notify;
524 int ret = -EINVAL;
525 unsigned long flags;
526
527 fedata = mappass->fedata;
528 /*
529 * __pvcalls_back_accept can race against pvcalls_back_accept.
530 * We only need to check the value of "cmd" on read. It could be
531 * done atomically, but to simplify the code on the write side, we
532 * use a spinlock.
533 */
534 spin_lock_irqsave(&mappass->copy_lock, flags);
535 req = &mappass->reqcopy;
536 if (req->cmd != PVCALLS_ACCEPT) {
537 spin_unlock_irqrestore(&mappass->copy_lock, flags);
538 return;
539 }
540 spin_unlock_irqrestore(&mappass->copy_lock, flags);
541
542 sock = sock_alloc();
543 if (sock == NULL)
544 goto out_error;
545 sock->type = mappass->sock->type;
546 sock->ops = mappass->sock->ops;
547
548 ret = inet_accept(mappass->sock, sock, O_NONBLOCK, true);
549 if (ret == -EAGAIN) {
550 sock_release(sock);
551 return;
552 }
553
554 map = pvcalls_new_active_socket(fedata,
555 req->u.accept.id_new,
556 req->u.accept.ref,
557 req->u.accept.evtchn,
558 sock);
559 if (!map) {
560 ret = -EFAULT;
561 sock_release(sock);
562 goto out_error;
563 }
564
565 map->sockpass = mappass;
566 iow = &map->ioworker;
567 atomic_inc(&map->read);
568 atomic_inc(&map->io);
569 queue_work(iow->wq, &iow->register_work);
570
571 out_error:
572 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
573 rsp->req_id = req->req_id;
574 rsp->cmd = req->cmd;
575 rsp->u.accept.id = req->u.accept.id;
576 rsp->ret = ret;
577 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);
578 if (notify)
579 notify_remote_via_irq(fedata->irq);
580
581 mappass->reqcopy.cmd = 0;
582 }
583
584 static void pvcalls_pass_sk_data_ready(struct sock *sock)
585 {
586 struct sockpass_mapping *mappass = sock->sk_user_data;
587 struct pvcalls_fedata *fedata;
588 struct xen_pvcalls_response *rsp;
589 unsigned long flags;
590 int notify;
591
592 if (mappass == NULL)
593 return;
594
595 fedata = mappass->fedata;
596 spin_lock_irqsave(&mappass->copy_lock, flags);
597 if (mappass->reqcopy.cmd == PVCALLS_POLL) {
598 rsp = RING_GET_RESPONSE(&fedata->ring,
599 fedata->ring.rsp_prod_pvt++);
600 rsp->req_id = mappass->reqcopy.req_id;
601 rsp->u.poll.id = mappass->reqcopy.u.poll.id;
602 rsp->cmd = mappass->reqcopy.cmd;
603 rsp->ret = 0;
604
605 mappass->reqcopy.cmd = 0;
606 spin_unlock_irqrestore(&mappass->copy_lock, flags);
607
608 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);
609 if (notify)
610 notify_remote_via_irq(mappass->fedata->irq);
611 } else {
612 spin_unlock_irqrestore(&mappass->copy_lock, flags);
613 queue_work(mappass->wq, &mappass->register_work);
614 }
615 }
616
617 static int pvcalls_back_bind(struct xenbus_device *dev,
618 struct xen_pvcalls_request *req)
619 {
620 struct pvcalls_fedata *fedata;
621 int ret;
622 struct sockpass_mapping *map;
623 struct xen_pvcalls_response *rsp;
624
625 fedata = dev_get_drvdata(&dev->dev);
626
627 map = kzalloc(sizeof(*map), GFP_KERNEL);
628 if (map == NULL) {
629 ret = -ENOMEM;
630 goto out;
631 }
632
633 INIT_WORK(&map->register_work, __pvcalls_back_accept);
634 spin_lock_init(&map->copy_lock);
635 map->wq = alloc_workqueue("pvcalls_wq", WQ_UNBOUND, 1);
636 if (!map->wq) {
637 ret = -ENOMEM;
638 goto out;
639 }
640
641 ret = sock_create(AF_INET, SOCK_STREAM, 0, &map->sock);
642 if (ret < 0)
643 goto out;
644
645 ret = inet_bind(map->sock, (struct sockaddr *)&req->u.bind.addr,
646 req->u.bind.len);
647 if (ret < 0)
648 goto out;
649
650 map->fedata = fedata;
651 map->id = req->u.bind.id;
652
653 down(&fedata->socket_lock);
654 ret = radix_tree_insert(&fedata->socketpass_mappings, map->id,
655 map);
656 up(&fedata->socket_lock);
657 if (ret)
658 goto out;
659
660 write_lock_bh(&map->sock->sk->sk_callback_lock);
661 map->saved_data_ready = map->sock->sk->sk_data_ready;
662 map->sock->sk->sk_user_data = map;
663 map->sock->sk->sk_data_ready = pvcalls_pass_sk_data_ready;
664 write_unlock_bh(&map->sock->sk->sk_callback_lock);
665
666 out:
667 if (ret) {
668 if (map && map->sock)
669 sock_release(map->sock);
670 if (map && map->wq)
671 destroy_workqueue(map->wq);
672 kfree(map);
673 }
674 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
675 rsp->req_id = req->req_id;
676 rsp->cmd = req->cmd;
677 rsp->u.bind.id = req->u.bind.id;
678 rsp->ret = ret;
679 return 0;
680 }
681
682 static int pvcalls_back_listen(struct xenbus_device *dev,
683 struct xen_pvcalls_request *req)
684 {
685 struct pvcalls_fedata *fedata;
686 int ret = -EINVAL;
687 struct sockpass_mapping *map;
688 struct xen_pvcalls_response *rsp;
689
690 fedata = dev_get_drvdata(&dev->dev);
691
692 down(&fedata->socket_lock);
693 map = radix_tree_lookup(&fedata->socketpass_mappings, req->u.listen.id);
694 up(&fedata->socket_lock);
695 if (map == NULL)
696 goto out;
697
698 ret = inet_listen(map->sock, req->u.listen.backlog);
699
700 out:
701 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
702 rsp->req_id = req->req_id;
703 rsp->cmd = req->cmd;
704 rsp->u.listen.id = req->u.listen.id;
705 rsp->ret = ret;
706 return 0;
707 }
708
709 static int pvcalls_back_accept(struct xenbus_device *dev,
710 struct xen_pvcalls_request *req)
711 {
712 struct pvcalls_fedata *fedata;
713 struct sockpass_mapping *mappass;
714 int ret = -EINVAL;
715 struct xen_pvcalls_response *rsp;
716 unsigned long flags;
717
718 fedata = dev_get_drvdata(&dev->dev);
719
720 down(&fedata->socket_lock);
721 mappass = radix_tree_lookup(&fedata->socketpass_mappings,
722 req->u.accept.id);
723 up(&fedata->socket_lock);
724 if (mappass == NULL)
725 goto out_error;
726
727 /*
728 * Limitation of the current implementation: only support one
729 * concurrent accept or poll call on one socket.
730 */
731 spin_lock_irqsave(&mappass->copy_lock, flags);
732 if (mappass->reqcopy.cmd != 0) {
733 spin_unlock_irqrestore(&mappass->copy_lock, flags);
734 ret = -EINTR;
735 goto out_error;
736 }
737
738 mappass->reqcopy = *req;
739 spin_unlock_irqrestore(&mappass->copy_lock, flags);
740 queue_work(mappass->wq, &mappass->register_work);
741
742 /* Tell the caller we don't need to send back a notification yet */
743 return -1;
744
745 out_error:
746 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
747 rsp->req_id = req->req_id;
748 rsp->cmd = req->cmd;
749 rsp->u.accept.id = req->u.accept.id;
750 rsp->ret = ret;
751 return 0;
752 }
753
754 static int pvcalls_back_poll(struct xenbus_device *dev,
755 struct xen_pvcalls_request *req)
756 {
757 struct pvcalls_fedata *fedata;
758 struct sockpass_mapping *mappass;
759 struct xen_pvcalls_response *rsp;
760 struct inet_connection_sock *icsk;
761 struct request_sock_queue *queue;
762 unsigned long flags;
763 int ret;
764 bool data;
765
766 fedata = dev_get_drvdata(&dev->dev);
767
768 down(&fedata->socket_lock);
769 mappass = radix_tree_lookup(&fedata->socketpass_mappings,
770 req->u.poll.id);
771 up(&fedata->socket_lock);
772 if (mappass == NULL)
773 return -EINVAL;
774
775 /*
776 * Limitation of the current implementation: only support one
777 * concurrent accept or poll call on one socket.
778 */
779 spin_lock_irqsave(&mappass->copy_lock, flags);
780 if (mappass->reqcopy.cmd != 0) {
781 ret = -EINTR;
782 goto out;
783 }
784
785 mappass->reqcopy = *req;
786 icsk = inet_csk(mappass->sock->sk);
787 queue = &icsk->icsk_accept_queue;
788 data = queue->rskq_accept_head != NULL;
789 if (data) {
790 mappass->reqcopy.cmd = 0;
791 ret = 0;
792 goto out;
793 }
794 spin_unlock_irqrestore(&mappass->copy_lock, flags);
795
796 /* Tell the caller we don't need to send back a notification yet */
797 return -1;
798
799 out:
800 spin_unlock_irqrestore(&mappass->copy_lock, flags);
801
802 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
803 rsp->req_id = req->req_id;
804 rsp->cmd = req->cmd;
805 rsp->u.poll.id = req->u.poll.id;
806 rsp->ret = ret;
807 return 0;
808 }
809
810 static int pvcalls_back_handle_cmd(struct xenbus_device *dev,
811 struct xen_pvcalls_request *req)
812 {
813 int ret = 0;
814
815 switch (req->cmd) {
816 case PVCALLS_SOCKET:
817 ret = pvcalls_back_socket(dev, req);
818 break;
819 case PVCALLS_CONNECT:
820 ret = pvcalls_back_connect(dev, req);
821 break;
822 case PVCALLS_RELEASE:
823 ret = pvcalls_back_release(dev, req);
824 break;
825 case PVCALLS_BIND:
826 ret = pvcalls_back_bind(dev, req);
827 break;
828 case PVCALLS_LISTEN:
829 ret = pvcalls_back_listen(dev, req);
830 break;
831 case PVCALLS_ACCEPT:
832 ret = pvcalls_back_accept(dev, req);
833 break;
834 case PVCALLS_POLL:
835 ret = pvcalls_back_poll(dev, req);
836 break;
837 default:
838 {
839 struct pvcalls_fedata *fedata;
840 struct xen_pvcalls_response *rsp;
841
842 fedata = dev_get_drvdata(&dev->dev);
843 rsp = RING_GET_RESPONSE(
844 &fedata->ring, fedata->ring.rsp_prod_pvt++);
845 rsp->req_id = req->req_id;
846 rsp->cmd = req->cmd;
847 rsp->ret = -ENOTSUPP;
848 break;
849 }
850 }
851 return ret;
852 }
853
854 static void pvcalls_back_work(struct pvcalls_fedata *fedata)
855 {
856 int notify, notify_all = 0, more = 1;
857 struct xen_pvcalls_request req;
858 struct xenbus_device *dev = fedata->dev;
859
860 while (more) {
861 while (RING_HAS_UNCONSUMED_REQUESTS(&fedata->ring)) {
862 RING_COPY_REQUEST(&fedata->ring,
863 fedata->ring.req_cons++,
864 &req);
865
866 if (!pvcalls_back_handle_cmd(dev, &req)) {
867 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(
868 &fedata->ring, notify);
869 notify_all += notify;
870 }
871 }
872
873 if (notify_all) {
874 notify_remote_via_irq(fedata->irq);
875 notify_all = 0;
876 }
877
878 RING_FINAL_CHECK_FOR_REQUESTS(&fedata->ring, more);
879 }
880 }
881
882 static irqreturn_t pvcalls_back_event(int irq, void *dev_id)
883 {
884 struct xenbus_device *dev = dev_id;
885 struct pvcalls_fedata *fedata = NULL;
886
887 if (dev == NULL)
888 return IRQ_HANDLED;
889
890 fedata = dev_get_drvdata(&dev->dev);
891 if (fedata == NULL)
892 return IRQ_HANDLED;
893
894 pvcalls_back_work(fedata);
895 return IRQ_HANDLED;
896 }
897
898 static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map)
899 {
900 struct sock_mapping *map = sock_map;
901 struct pvcalls_ioworker *iow;
902
903 if (map == NULL || map->sock == NULL || map->sock->sk == NULL ||
904 map->sock->sk->sk_user_data != map)
905 return IRQ_HANDLED;
906
907 iow = &map->ioworker;
908
909 atomic_inc(&map->write);
910 atomic_inc(&map->io);
911 queue_work(iow->wq, &iow->register_work);
912
913 return IRQ_HANDLED;
914 }
915
916 static int backend_connect(struct xenbus_device *dev)
917 {
918 int err, evtchn;
919 grant_ref_t ring_ref;
920 struct pvcalls_fedata *fedata = NULL;
921
922 fedata = kzalloc(sizeof(struct pvcalls_fedata), GFP_KERNEL);
923 if (!fedata)
924 return -ENOMEM;
925
926 fedata->irq = -1;
927 err = xenbus_scanf(XBT_NIL, dev->otherend, "port", "%u",
928 &evtchn);
929 if (err != 1) {
930 err = -EINVAL;
931 xenbus_dev_fatal(dev, err, "reading %s/event-channel",
932 dev->otherend);
933 goto error;
934 }
935
936 err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", "%u", &ring_ref);
937 if (err != 1) {
938 err = -EINVAL;
939 xenbus_dev_fatal(dev, err, "reading %s/ring-ref",
940 dev->otherend);
941 goto error;
942 }
943
944 err = bind_interdomain_evtchn_to_irq(dev->otherend_id, evtchn);
945 if (err < 0)
946 goto error;
947 fedata->irq = err;
948
949 err = request_threaded_irq(fedata->irq, NULL, pvcalls_back_event,
950 IRQF_ONESHOT, "pvcalls-back", dev);
951 if (err < 0)
952 goto error;
953
954 err = xenbus_map_ring_valloc(dev, &ring_ref, 1,
955 (void **)&fedata->sring);
956 if (err < 0)
957 goto error;
958
959 BACK_RING_INIT(&fedata->ring, fedata->sring, XEN_PAGE_SIZE * 1);
960 fedata->dev = dev;
961
962 INIT_LIST_HEAD(&fedata->socket_mappings);
963 INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL);
964 sema_init(&fedata->socket_lock, 1);
965 dev_set_drvdata(&dev->dev, fedata);
966
967 down(&pvcalls_back_global.frontends_lock);
968 list_add_tail(&fedata->list, &pvcalls_back_global.frontends);
969 up(&pvcalls_back_global.frontends_lock);
970
971 return 0;
972
973 error:
974 if (fedata->irq >= 0)
975 unbind_from_irqhandler(fedata->irq, dev);
976 if (fedata->sring != NULL)
977 xenbus_unmap_ring_vfree(dev, fedata->sring);
978 kfree(fedata);
979 return err;
980 }
981
982 static int backend_disconnect(struct xenbus_device *dev)
983 {
984 struct pvcalls_fedata *fedata;
985 struct sock_mapping *map, *n;
986 struct sockpass_mapping *mappass;
987 struct radix_tree_iter iter;
988 void **slot;
989
990
991 fedata = dev_get_drvdata(&dev->dev);
992
993 down(&fedata->socket_lock);
994 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {
995 list_del(&map->list);
996 pvcalls_back_release_active(dev, fedata, map);
997 }
998
999 radix_tree_for_each_slot(slot, &fedata->socketpass_mappings, &iter, 0) {
1000 mappass = radix_tree_deref_slot(slot);
1001 if (!mappass)
1002 continue;
1003 if (radix_tree_exception(mappass)) {
1004 if (radix_tree_deref_retry(mappass))
1005 slot = radix_tree_iter_retry(&iter);
1006 } else {
1007 radix_tree_delete(&fedata->socketpass_mappings,
1008 mappass->id);
1009 pvcalls_back_release_passive(dev, fedata, mappass);
1010 }
1011 }
1012 up(&fedata->socket_lock);
1013
1014 unbind_from_irqhandler(fedata->irq, dev);
1015 xenbus_unmap_ring_vfree(dev, fedata->sring);
1016
1017 list_del(&fedata->list);
1018 kfree(fedata);
1019 dev_set_drvdata(&dev->dev, NULL);
1020
1021 return 0;
1022 }
1023
1024 static int pvcalls_back_probe(struct xenbus_device *dev,
1025 const struct xenbus_device_id *id)
1026 {
1027 int err, abort;
1028 struct xenbus_transaction xbt;
1029
1030 again:
1031 abort = 1;
1032
1033 err = xenbus_transaction_start(&xbt);
1034 if (err) {
1035 pr_warn("%s cannot create xenstore transaction\n", __func__);
1036 return err;
1037 }
1038
1039 err = xenbus_printf(xbt, dev->nodename, "versions", "%s",
1040 PVCALLS_VERSIONS);
1041 if (err) {
1042 pr_warn("%s write out 'versions' failed\n", __func__);
1043 goto abort;
1044 }
1045
1046 err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u",
1047 MAX_RING_ORDER);
1048 if (err) {
1049 pr_warn("%s write out 'max-page-order' failed\n", __func__);
1050 goto abort;
1051 }
1052
1053 err = xenbus_printf(xbt, dev->nodename, "function-calls",
1054 XENBUS_FUNCTIONS_CALLS);
1055 if (err) {
1056 pr_warn("%s write out 'function-calls' failed\n", __func__);
1057 goto abort;
1058 }
1059
1060 abort = 0;
1061 abort:
1062 err = xenbus_transaction_end(xbt, abort);
1063 if (err) {
1064 if (err == -EAGAIN && !abort)
1065 goto again;
1066 pr_warn("%s cannot complete xenstore transaction\n", __func__);
1067 return err;
1068 }
1069
1070 if (abort)
1071 return -EFAULT;
1072
1073 xenbus_switch_state(dev, XenbusStateInitWait);
1074
1075 return 0;
1076 }
1077
1078 static void set_backend_state(struct xenbus_device *dev,
1079 enum xenbus_state state)
1080 {
1081 while (dev->state != state) {
1082 switch (dev->state) {
1083 case XenbusStateClosed:
1084 switch (state) {
1085 case XenbusStateInitWait:
1086 case XenbusStateConnected:
1087 xenbus_switch_state(dev, XenbusStateInitWait);
1088 break;
1089 case XenbusStateClosing:
1090 xenbus_switch_state(dev, XenbusStateClosing);
1091 break;
1092 default:
1093 WARN_ON(1);
1094 }
1095 break;
1096 case XenbusStateInitWait:
1097 case XenbusStateInitialised:
1098 switch (state) {
1099 case XenbusStateConnected:
1100 backend_connect(dev);
1101 xenbus_switch_state(dev, XenbusStateConnected);
1102 break;
1103 case XenbusStateClosing:
1104 case XenbusStateClosed:
1105 xenbus_switch_state(dev, XenbusStateClosing);
1106 break;
1107 default:
1108 WARN_ON(1);
1109 }
1110 break;
1111 case XenbusStateConnected:
1112 switch (state) {
1113 case XenbusStateInitWait:
1114 case XenbusStateClosing:
1115 case XenbusStateClosed:
1116 down(&pvcalls_back_global.frontends_lock);
1117 backend_disconnect(dev);
1118 up(&pvcalls_back_global.frontends_lock);
1119 xenbus_switch_state(dev, XenbusStateClosing);
1120 break;
1121 default:
1122 WARN_ON(1);
1123 }
1124 break;
1125 case XenbusStateClosing:
1126 switch (state) {
1127 case XenbusStateInitWait:
1128 case XenbusStateConnected:
1129 case XenbusStateClosed:
1130 xenbus_switch_state(dev, XenbusStateClosed);
1131 break;
1132 default:
1133 WARN_ON(1);
1134 }
1135 break;
1136 default:
1137 WARN_ON(1);
1138 }
1139 }
1140 }
1141
1142 static void pvcalls_back_changed(struct xenbus_device *dev,
1143 enum xenbus_state frontend_state)
1144 {
1145 switch (frontend_state) {
1146 case XenbusStateInitialising:
1147 set_backend_state(dev, XenbusStateInitWait);
1148 break;
1149
1150 case XenbusStateInitialised:
1151 case XenbusStateConnected:
1152 set_backend_state(dev, XenbusStateConnected);
1153 break;
1154
1155 case XenbusStateClosing:
1156 set_backend_state(dev, XenbusStateClosing);
1157 break;
1158
1159 case XenbusStateClosed:
1160 set_backend_state(dev, XenbusStateClosed);
1161 if (xenbus_dev_is_online(dev))
1162 break;
1163 device_unregister(&dev->dev);
1164 break;
1165 case XenbusStateUnknown:
1166 set_backend_state(dev, XenbusStateClosed);
1167 device_unregister(&dev->dev);
1168 break;
1169
1170 default:
1171 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1172 frontend_state);
1173 break;
1174 }
1175 }
1176
1177 static int pvcalls_back_remove(struct xenbus_device *dev)
1178 {
1179 return 0;
1180 }
1181
1182 static int pvcalls_back_uevent(struct xenbus_device *xdev,
1183 struct kobj_uevent_env *env)
1184 {
1185 return 0;
1186 }
1187
1188 static const struct xenbus_device_id pvcalls_back_ids[] = {
1189 { "pvcalls" },
1190 { "" }
1191 };
1192
1193 static struct xenbus_driver pvcalls_back_driver = {
1194 .ids = pvcalls_back_ids,
1195 .probe = pvcalls_back_probe,
1196 .remove = pvcalls_back_remove,
1197 .uevent = pvcalls_back_uevent,
1198 .otherend_changed = pvcalls_back_changed,
1199 };
1200
1201 static int __init pvcalls_back_init(void)
1202 {
1203 int ret;
1204
1205 if (!xen_domain())
1206 return -ENODEV;
1207
1208 ret = xenbus_register_backend(&pvcalls_back_driver);
1209 if (ret < 0)
1210 return ret;
1211
1212 sema_init(&pvcalls_back_global.frontends_lock, 1);
1213 INIT_LIST_HEAD(&pvcalls_back_global.frontends);
1214 return 0;
1215 }
1216 module_init(pvcalls_back_init);
1217
1218 static void __exit pvcalls_back_fin(void)
1219 {
1220 struct pvcalls_fedata *fedata, *nfedata;
1221
1222 down(&pvcalls_back_global.frontends_lock);
1223 list_for_each_entry_safe(fedata, nfedata,
1224 &pvcalls_back_global.frontends, list) {
1225 backend_disconnect(fedata->dev);
1226 }
1227 up(&pvcalls_back_global.frontends_lock);
1228
1229 xenbus_unregister_driver(&pvcalls_back_driver);
1230 }
1231
1232 module_exit(pvcalls_back_fin);
1233
1234 MODULE_DESCRIPTION("Xen PV Calls backend driver");
1235 MODULE_AUTHOR("Stefano Stabellini <sstabellini@kernel.org>");
1236 MODULE_LICENSE("GPL");
Linux with added FPC-III support