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Linux 4.19.133
[linux/fpc-iii.git] / drivers / xen / pvcalls-back.c
blob398fd8b1639d486bcea1103e79901b4358a18a75
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 atomic_set(&map->read, 0);
165 intf->in_error = ret;
166 } else
167 intf->in_prod = prod + ret;
168 /* update the indexes, then notify the other end */
169 virt_wmb();
170 notify_remote_via_irq(map->irq);
171
172 return;
173 }
174
175 static void pvcalls_conn_back_write(struct sock_mapping *map)
176 {
177 struct pvcalls_data_intf *intf = map->ring;
178 struct pvcalls_data *data = &map->data;
179 struct msghdr msg;
180 struct kvec vec[2];
181 RING_IDX cons, prod, size, array_size;
182 int ret;
183
184 cons = intf->out_cons;
185 prod = intf->out_prod;
186 /* read the indexes before dealing with the data */
187 virt_mb();
188
189 array_size = XEN_FLEX_RING_SIZE(map->ring_order);
190 size = pvcalls_queued(prod, cons, array_size);
191 if (size == 0)
192 return;
193
194 memset(&msg, 0, sizeof(msg));
195 msg.msg_flags |= MSG_DONTWAIT;
196 if (pvcalls_mask(prod, array_size) > pvcalls_mask(cons, array_size)) {
197 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
198 vec[0].iov_len = size;
199 iov_iter_kvec(&msg.msg_iter, ITER_KVEC|READ, vec, 1, size);
200 } else {
201 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
202 vec[0].iov_len = array_size - pvcalls_mask(cons, array_size);
203 vec[1].iov_base = data->out;
204 vec[1].iov_len = size - vec[0].iov_len;
205 iov_iter_kvec(&msg.msg_iter, ITER_KVEC|READ, vec, 2, size);
206 }
207
208 atomic_set(&map->write, 0);
209 ret = inet_sendmsg(map->sock, &msg, size);
210 if (ret == -EAGAIN || (ret >= 0 && ret < size)) {
211 atomic_inc(&map->write);
212 atomic_inc(&map->io);
213 }
214 if (ret == -EAGAIN)
215 return;
216
217 /* write the data, then update the indexes */
218 virt_wmb();
219 if (ret < 0) {
220 intf->out_error = ret;
221 } else {
222 intf->out_error = 0;
223 intf->out_cons = cons + ret;
224 prod = intf->out_prod;
225 }
226 /* update the indexes, then notify the other end */
227 virt_wmb();
228 if (prod != cons + ret)
229 atomic_inc(&map->write);
230 notify_remote_via_irq(map->irq);
231 }
232
233 static void pvcalls_back_ioworker(struct work_struct *work)
234 {
235 struct pvcalls_ioworker *ioworker = container_of(work,
236 struct pvcalls_ioworker, register_work);
237 struct sock_mapping *map = container_of(ioworker, struct sock_mapping,
238 ioworker);
239
240 while (atomic_read(&map->io) > 0) {
241 if (atomic_read(&map->release) > 0) {
242 atomic_set(&map->release, 0);
243 return;
244 }
245
246 if (atomic_read(&map->read) > 0)
247 pvcalls_conn_back_read(map);
248 if (atomic_read(&map->write) > 0)
249 pvcalls_conn_back_write(map);
250
251 atomic_dec(&map->io);
252 }
253 }
254
255 static int pvcalls_back_socket(struct xenbus_device *dev,
256 struct xen_pvcalls_request *req)
257 {
258 struct pvcalls_fedata *fedata;
259 int ret;
260 struct xen_pvcalls_response *rsp;
261
262 fedata = dev_get_drvdata(&dev->dev);
263
264 if (req->u.socket.domain != AF_INET ||
265 req->u.socket.type != SOCK_STREAM ||
266 (req->u.socket.protocol != IPPROTO_IP &&
267 req->u.socket.protocol != AF_INET))
268 ret = -EAFNOSUPPORT;
269 else
270 ret = 0;
271
272 /* leave the actual socket allocation for later */
273
274 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
275 rsp->req_id = req->req_id;
276 rsp->cmd = req->cmd;
277 rsp->u.socket.id = req->u.socket.id;
278 rsp->ret = ret;
279
280 return 0;
281 }
282
283 static void pvcalls_sk_state_change(struct sock *sock)
284 {
285 struct sock_mapping *map = sock->sk_user_data;
286
287 if (map == NULL)
288 return;
289
290 atomic_inc(&map->read);
291 notify_remote_via_irq(map->irq);
292 }
293
294 static void pvcalls_sk_data_ready(struct sock *sock)
295 {
296 struct sock_mapping *map = sock->sk_user_data;
297 struct pvcalls_ioworker *iow;
298
299 if (map == NULL)
300 return;
301
302 iow = &map->ioworker;
303 atomic_inc(&map->read);
304 atomic_inc(&map->io);
305 queue_work(iow->wq, &iow->register_work);
306 }
307
308 static struct sock_mapping *pvcalls_new_active_socket(
309 struct pvcalls_fedata *fedata,
310 uint64_t id,
311 grant_ref_t ref,
312 uint32_t evtchn,
313 struct socket *sock)
314 {
315 int ret;
316 struct sock_mapping *map;
317 void *page;
318
319 map = kzalloc(sizeof(*map), GFP_KERNEL);
320 if (map == NULL)
321 return NULL;
322
323 map->fedata = fedata;
324 map->sock = sock;
325 map->id = id;
326 map->ref = ref;
327
328 ret = xenbus_map_ring_valloc(fedata->dev, &ref, 1, &page);
329 if (ret < 0)
330 goto out;
331 map->ring = page;
332 map->ring_order = map->ring->ring_order;
333 /* first read the order, then map the data ring */
334 virt_rmb();
335 if (map->ring_order > MAX_RING_ORDER) {
336 pr_warn("%s frontend requested ring_order %u, which is > MAX (%u)\n",
337 __func__, map->ring_order, MAX_RING_ORDER);
338 goto out;
339 }
340 ret = xenbus_map_ring_valloc(fedata->dev, map->ring->ref,
341 (1 << map->ring_order), &page);
342 if (ret < 0)
343 goto out;
344 map->bytes = page;
345
346 ret = bind_interdomain_evtchn_to_irqhandler(fedata->dev->otherend_id,
347 evtchn,
348 pvcalls_back_conn_event,
349 0,
350 "pvcalls-backend",
351 map);
352 if (ret < 0)
353 goto out;
354 map->irq = ret;
355
356 map->data.in = map->bytes;
357 map->data.out = map->bytes + XEN_FLEX_RING_SIZE(map->ring_order);
358
359 map->ioworker.wq = alloc_workqueue("pvcalls_io", WQ_UNBOUND, 1);
360 if (!map->ioworker.wq)
361 goto out;
362 atomic_set(&map->io, 1);
363 INIT_WORK(&map->ioworker.register_work, pvcalls_back_ioworker);
364
365 down(&fedata->socket_lock);
366 list_add_tail(&map->list, &fedata->socket_mappings);
367 up(&fedata->socket_lock);
368
369 write_lock_bh(&map->sock->sk->sk_callback_lock);
370 map->saved_data_ready = map->sock->sk->sk_data_ready;
371 map->sock->sk->sk_user_data = map;
372 map->sock->sk->sk_data_ready = pvcalls_sk_data_ready;
373 map->sock->sk->sk_state_change = pvcalls_sk_state_change;
374 write_unlock_bh(&map->sock->sk->sk_callback_lock);
375
376 return map;
377 out:
378 down(&fedata->socket_lock);
379 list_del(&map->list);
380 pvcalls_back_release_active(fedata->dev, fedata, map);
381 up(&fedata->socket_lock);
382 return NULL;
383 }
384
385 static int pvcalls_back_connect(struct xenbus_device *dev,
386 struct xen_pvcalls_request *req)
387 {
388 struct pvcalls_fedata *fedata;
389 int ret = -EINVAL;
390 struct socket *sock;
391 struct sock_mapping *map;
392 struct xen_pvcalls_response *rsp;
393 struct sockaddr *sa = (struct sockaddr *)&req->u.connect.addr;
394
395 fedata = dev_get_drvdata(&dev->dev);
396
397 if (req->u.connect.len < sizeof(sa->sa_family) ||
398 req->u.connect.len > sizeof(req->u.connect.addr) ||
399 sa->sa_family != AF_INET)
400 goto out;
401
402 ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock);
403 if (ret < 0)
404 goto out;
405 ret = inet_stream_connect(sock, sa, req->u.connect.len, 0);
406 if (ret < 0) {
407 sock_release(sock);
408 goto out;
409 }
410
411 map = pvcalls_new_active_socket(fedata,
412 req->u.connect.id,
413 req->u.connect.ref,
414 req->u.connect.evtchn,
415 sock);
416 if (!map) {
417 ret = -EFAULT;
418 sock_release(sock);
419 }
420
421 out:
422 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
423 rsp->req_id = req->req_id;
424 rsp->cmd = req->cmd;
425 rsp->u.connect.id = req->u.connect.id;
426 rsp->ret = ret;
427
428 return 0;
429 }
430
431 static int pvcalls_back_release_active(struct xenbus_device *dev,
432 struct pvcalls_fedata *fedata,
433 struct sock_mapping *map)
434 {
435 disable_irq(map->irq);
436 if (map->sock->sk != NULL) {
437 write_lock_bh(&map->sock->sk->sk_callback_lock);
438 map->sock->sk->sk_user_data = NULL;
439 map->sock->sk->sk_data_ready = map->saved_data_ready;
440 write_unlock_bh(&map->sock->sk->sk_callback_lock);
441 }
442
443 atomic_set(&map->release, 1);
444 flush_work(&map->ioworker.register_work);
445
446 xenbus_unmap_ring_vfree(dev, map->bytes);
447 xenbus_unmap_ring_vfree(dev, (void *)map->ring);
448 unbind_from_irqhandler(map->irq, map);
449
450 sock_release(map->sock);
451 kfree(map);
452
453 return 0;
454 }
455
456 static int pvcalls_back_release_passive(struct xenbus_device *dev,
457 struct pvcalls_fedata *fedata,
458 struct sockpass_mapping *mappass)
459 {
460 if (mappass->sock->sk != NULL) {
461 write_lock_bh(&mappass->sock->sk->sk_callback_lock);
462 mappass->sock->sk->sk_user_data = NULL;
463 mappass->sock->sk->sk_data_ready = mappass->saved_data_ready;
464 write_unlock_bh(&mappass->sock->sk->sk_callback_lock);
465 }
466 sock_release(mappass->sock);
467 flush_workqueue(mappass->wq);
468 destroy_workqueue(mappass->wq);
469 kfree(mappass);
470
471 return 0;
472 }
473
474 static int pvcalls_back_release(struct xenbus_device *dev,
475 struct xen_pvcalls_request *req)
476 {
477 struct pvcalls_fedata *fedata;
478 struct sock_mapping *map, *n;
479 struct sockpass_mapping *mappass;
480 int ret = 0;
481 struct xen_pvcalls_response *rsp;
482
483 fedata = dev_get_drvdata(&dev->dev);
484
485 down(&fedata->socket_lock);
486 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {
487 if (map->id == req->u.release.id) {
488 list_del(&map->list);
489 up(&fedata->socket_lock);
490 ret = pvcalls_back_release_active(dev, fedata, map);
491 goto out;
492 }
493 }
494 mappass = radix_tree_lookup(&fedata->socketpass_mappings,
495 req->u.release.id);
496 if (mappass != NULL) {
497 radix_tree_delete(&fedata->socketpass_mappings, mappass->id);
498 up(&fedata->socket_lock);
499 ret = pvcalls_back_release_passive(dev, fedata, mappass);
500 } else
501 up(&fedata->socket_lock);
502
503 out:
504 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
505 rsp->req_id = req->req_id;
506 rsp->u.release.id = req->u.release.id;
507 rsp->cmd = req->cmd;
508 rsp->ret = ret;
509 return 0;
510 }
511
512 static void __pvcalls_back_accept(struct work_struct *work)
513 {
514 struct sockpass_mapping *mappass = container_of(
515 work, struct sockpass_mapping, register_work);
516 struct sock_mapping *map;
517 struct pvcalls_ioworker *iow;
518 struct pvcalls_fedata *fedata;
519 struct socket *sock;
520 struct xen_pvcalls_response *rsp;
521 struct xen_pvcalls_request *req;
522 int notify;
523 int ret = -EINVAL;
524 unsigned long flags;
525
526 fedata = mappass->fedata;
527 /*
528 * __pvcalls_back_accept can race against pvcalls_back_accept.
529 * We only need to check the value of "cmd" on read. It could be
530 * done atomically, but to simplify the code on the write side, we
531 * use a spinlock.
532 */
533 spin_lock_irqsave(&mappass->copy_lock, flags);
534 req = &mappass->reqcopy;
535 if (req->cmd != PVCALLS_ACCEPT) {
536 spin_unlock_irqrestore(&mappass->copy_lock, flags);
537 return;
538 }
539 spin_unlock_irqrestore(&mappass->copy_lock, flags);
540
541 sock = sock_alloc();
542 if (sock == NULL)
543 goto out_error;
544 sock->type = mappass->sock->type;
545 sock->ops = mappass->sock->ops;
546
547 ret = inet_accept(mappass->sock, sock, O_NONBLOCK, true);
548 if (ret == -EAGAIN) {
549 sock_release(sock);
550 return;
551 }
552
553 map = pvcalls_new_active_socket(fedata,
554 req->u.accept.id_new,
555 req->u.accept.ref,
556 req->u.accept.evtchn,
557 sock);
558 if (!map) {
559 ret = -EFAULT;
560 sock_release(sock);
561 goto out_error;
562 }
563
564 map->sockpass = mappass;
565 iow = &map->ioworker;
566 atomic_inc(&map->read);
567 atomic_inc(&map->io);
568 queue_work(iow->wq, &iow->register_work);
569
570 out_error:
571 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
572 rsp->req_id = req->req_id;
573 rsp->cmd = req->cmd;
574 rsp->u.accept.id = req->u.accept.id;
575 rsp->ret = ret;
576 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);
577 if (notify)
578 notify_remote_via_irq(fedata->irq);
579
580 mappass->reqcopy.cmd = 0;
581 }
582
583 static void pvcalls_pass_sk_data_ready(struct sock *sock)
584 {
585 struct sockpass_mapping *mappass = sock->sk_user_data;
586 struct pvcalls_fedata *fedata;
587 struct xen_pvcalls_response *rsp;
588 unsigned long flags;
589 int notify;
590
591 if (mappass == NULL)
592 return;
593
594 fedata = mappass->fedata;
595 spin_lock_irqsave(&mappass->copy_lock, flags);
596 if (mappass->reqcopy.cmd == PVCALLS_POLL) {
597 rsp = RING_GET_RESPONSE(&fedata->ring,
598 fedata->ring.rsp_prod_pvt++);
599 rsp->req_id = mappass->reqcopy.req_id;
600 rsp->u.poll.id = mappass->reqcopy.u.poll.id;
601 rsp->cmd = mappass->reqcopy.cmd;
602 rsp->ret = 0;
603
604 mappass->reqcopy.cmd = 0;
605 spin_unlock_irqrestore(&mappass->copy_lock, flags);
606
607 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);
608 if (notify)
609 notify_remote_via_irq(mappass->fedata->irq);
610 } else {
611 spin_unlock_irqrestore(&mappass->copy_lock, flags);
612 queue_work(mappass->wq, &mappass->register_work);
613 }
614 }
615
616 static int pvcalls_back_bind(struct xenbus_device *dev,
617 struct xen_pvcalls_request *req)
618 {
619 struct pvcalls_fedata *fedata;
620 int ret;
621 struct sockpass_mapping *map;
622 struct xen_pvcalls_response *rsp;
623
624 fedata = dev_get_drvdata(&dev->dev);
625
626 map = kzalloc(sizeof(*map), GFP_KERNEL);
627 if (map == NULL) {
628 ret = -ENOMEM;
629 goto out;
630 }
631
632 INIT_WORK(&map->register_work, __pvcalls_back_accept);
633 spin_lock_init(&map->copy_lock);
634 map->wq = alloc_workqueue("pvcalls_wq", WQ_UNBOUND, 1);
635 if (!map->wq) {
636 ret = -ENOMEM;
637 goto out;
638 }
639
640 ret = sock_create(AF_INET, SOCK_STREAM, 0, &map->sock);
641 if (ret < 0)
642 goto out;
643
644 ret = inet_bind(map->sock, (struct sockaddr *)&req->u.bind.addr,
645 req->u.bind.len);
646 if (ret < 0)
647 goto out;
648
649 map->fedata = fedata;
650 map->id = req->u.bind.id;
651
652 down(&fedata->socket_lock);
653 ret = radix_tree_insert(&fedata->socketpass_mappings, map->id,
654 map);
655 up(&fedata->socket_lock);
656 if (ret)
657 goto out;
658
659 write_lock_bh(&map->sock->sk->sk_callback_lock);
660 map->saved_data_ready = map->sock->sk->sk_data_ready;
661 map->sock->sk->sk_user_data = map;
662 map->sock->sk->sk_data_ready = pvcalls_pass_sk_data_ready;
663 write_unlock_bh(&map->sock->sk->sk_callback_lock);
664
665 out:
666 if (ret) {
667 if (map && map->sock)
668 sock_release(map->sock);
669 if (map && map->wq)
670 destroy_workqueue(map->wq);
671 kfree(map);
672 }
673 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
674 rsp->req_id = req->req_id;
675 rsp->cmd = req->cmd;
676 rsp->u.bind.id = req->u.bind.id;
677 rsp->ret = ret;
678 return 0;
679 }
680
681 static int pvcalls_back_listen(struct xenbus_device *dev,
682 struct xen_pvcalls_request *req)
683 {
684 struct pvcalls_fedata *fedata;
685 int ret = -EINVAL;
686 struct sockpass_mapping *map;
687 struct xen_pvcalls_response *rsp;
688
689 fedata = dev_get_drvdata(&dev->dev);
690
691 down(&fedata->socket_lock);
692 map = radix_tree_lookup(&fedata->socketpass_mappings, req->u.listen.id);
693 up(&fedata->socket_lock);
694 if (map == NULL)
695 goto out;
696
697 ret = inet_listen(map->sock, req->u.listen.backlog);
698
699 out:
700 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
701 rsp->req_id = req->req_id;
702 rsp->cmd = req->cmd;
703 rsp->u.listen.id = req->u.listen.id;
704 rsp->ret = ret;
705 return 0;
706 }
707
708 static int pvcalls_back_accept(struct xenbus_device *dev,
709 struct xen_pvcalls_request *req)
710 {
711 struct pvcalls_fedata *fedata;
712 struct sockpass_mapping *mappass;
713 int ret = -EINVAL;
714 struct xen_pvcalls_response *rsp;
715 unsigned long flags;
716
717 fedata = dev_get_drvdata(&dev->dev);
718
719 down(&fedata->socket_lock);
720 mappass = radix_tree_lookup(&fedata->socketpass_mappings,
721 req->u.accept.id);
722 up(&fedata->socket_lock);
723 if (mappass == NULL)
724 goto out_error;
725
726 /*
727 * Limitation of the current implementation: only support one
728 * concurrent accept or poll call on one socket.
729 */
730 spin_lock_irqsave(&mappass->copy_lock, flags);
731 if (mappass->reqcopy.cmd != 0) {
732 spin_unlock_irqrestore(&mappass->copy_lock, flags);
733 ret = -EINTR;
734 goto out_error;
735 }
736
737 mappass->reqcopy = *req;
738 spin_unlock_irqrestore(&mappass->copy_lock, flags);
739 queue_work(mappass->wq, &mappass->register_work);
740
741 /* Tell the caller we don't need to send back a notification yet */
742 return -1;
743
744 out_error:
745 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
746 rsp->req_id = req->req_id;
747 rsp->cmd = req->cmd;
748 rsp->u.accept.id = req->u.accept.id;
749 rsp->ret = ret;
750 return 0;
751 }
752
753 static int pvcalls_back_poll(struct xenbus_device *dev,
754 struct xen_pvcalls_request *req)
755 {
756 struct pvcalls_fedata *fedata;
757 struct sockpass_mapping *mappass;
758 struct xen_pvcalls_response *rsp;
759 struct inet_connection_sock *icsk;
760 struct request_sock_queue *queue;
761 unsigned long flags;
762 int ret;
763 bool data;
764
765 fedata = dev_get_drvdata(&dev->dev);
766
767 down(&fedata->socket_lock);
768 mappass = radix_tree_lookup(&fedata->socketpass_mappings,
769 req->u.poll.id);
770 up(&fedata->socket_lock);
771 if (mappass == NULL)
772 return -EINVAL;
773
774 /*
775 * Limitation of the current implementation: only support one
776 * concurrent accept or poll call on one socket.
777 */
778 spin_lock_irqsave(&mappass->copy_lock, flags);
779 if (mappass->reqcopy.cmd != 0) {
780 ret = -EINTR;
781 goto out;
782 }
783
784 mappass->reqcopy = *req;
785 icsk = inet_csk(mappass->sock->sk);
786 queue = &icsk->icsk_accept_queue;
787 data = READ_ONCE(queue->rskq_accept_head) != NULL;
788 if (data) {
789 mappass->reqcopy.cmd = 0;
790 ret = 0;
791 goto out;
792 }
793 spin_unlock_irqrestore(&mappass->copy_lock, flags);
794
795 /* Tell the caller we don't need to send back a notification yet */
796 return -1;
797
798 out:
799 spin_unlock_irqrestore(&mappass->copy_lock, flags);
800
801 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
802 rsp->req_id = req->req_id;
803 rsp->cmd = req->cmd;
804 rsp->u.poll.id = req->u.poll.id;
805 rsp->ret = ret;
806 return 0;
807 }
808
809 static int pvcalls_back_handle_cmd(struct xenbus_device *dev,
810 struct xen_pvcalls_request *req)
811 {
812 int ret = 0;
813
814 switch (req->cmd) {
815 case PVCALLS_SOCKET:
816 ret = pvcalls_back_socket(dev, req);
817 break;
818 case PVCALLS_CONNECT:
819 ret = pvcalls_back_connect(dev, req);
820 break;
821 case PVCALLS_RELEASE:
822 ret = pvcalls_back_release(dev, req);
823 break;
824 case PVCALLS_BIND:
825 ret = pvcalls_back_bind(dev, req);
826 break;
827 case PVCALLS_LISTEN:
828 ret = pvcalls_back_listen(dev, req);
829 break;
830 case PVCALLS_ACCEPT:
831 ret = pvcalls_back_accept(dev, req);
832 break;
833 case PVCALLS_POLL:
834 ret = pvcalls_back_poll(dev, req);
835 break;
836 default:
837 {
838 struct pvcalls_fedata *fedata;
839 struct xen_pvcalls_response *rsp;
840
841 fedata = dev_get_drvdata(&dev->dev);
842 rsp = RING_GET_RESPONSE(
843 &fedata->ring, fedata->ring.rsp_prod_pvt++);
844 rsp->req_id = req->req_id;
845 rsp->cmd = req->cmd;
846 rsp->ret = -ENOTSUPP;
847 break;
848 }
849 }
850 return ret;
851 }
852
853 static void pvcalls_back_work(struct pvcalls_fedata *fedata)
854 {
855 int notify, notify_all = 0, more = 1;
856 struct xen_pvcalls_request req;
857 struct xenbus_device *dev = fedata->dev;
858
859 while (more) {
860 while (RING_HAS_UNCONSUMED_REQUESTS(&fedata->ring)) {
861 RING_COPY_REQUEST(&fedata->ring,
862 fedata->ring.req_cons++,
863 &req);
864
865 if (!pvcalls_back_handle_cmd(dev, &req)) {
866 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(
867 &fedata->ring, notify);
868 notify_all += notify;
869 }
870 }
871
872 if (notify_all) {
873 notify_remote_via_irq(fedata->irq);
874 notify_all = 0;
875 }
876
877 RING_FINAL_CHECK_FOR_REQUESTS(&fedata->ring, more);
878 }
879 }
880
881 static irqreturn_t pvcalls_back_event(int irq, void *dev_id)
882 {
883 struct xenbus_device *dev = dev_id;
884 struct pvcalls_fedata *fedata = NULL;
885
886 if (dev == NULL)
887 return IRQ_HANDLED;
888
889 fedata = dev_get_drvdata(&dev->dev);
890 if (fedata == NULL)
891 return IRQ_HANDLED;
892
893 pvcalls_back_work(fedata);
894 return IRQ_HANDLED;
895 }
896
897 static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map)
898 {
899 struct sock_mapping *map = sock_map;
900 struct pvcalls_ioworker *iow;
901
902 if (map == NULL || map->sock == NULL || map->sock->sk == NULL ||
903 map->sock->sk->sk_user_data != map)
904 return IRQ_HANDLED;
905
906 iow = &map->ioworker;
907
908 atomic_inc(&map->write);
909 atomic_inc(&map->io);
910 queue_work(iow->wq, &iow->register_work);
911
912 return IRQ_HANDLED;
913 }
914
915 static int backend_connect(struct xenbus_device *dev)
916 {
917 int err, evtchn;
918 grant_ref_t ring_ref;
919 struct pvcalls_fedata *fedata = NULL;
920
921 fedata = kzalloc(sizeof(struct pvcalls_fedata), GFP_KERNEL);
922 if (!fedata)
923 return -ENOMEM;
924
925 fedata->irq = -1;
926 err = xenbus_scanf(XBT_NIL, dev->otherend, "port", "%u",
927 &evtchn);
928 if (err != 1) {
929 err = -EINVAL;
930 xenbus_dev_fatal(dev, err, "reading %s/event-channel",
931 dev->otherend);
932 goto error;
933 }
934
935 err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", "%u", &ring_ref);
936 if (err != 1) {
937 err = -EINVAL;
938 xenbus_dev_fatal(dev, err, "reading %s/ring-ref",
939 dev->otherend);
940 goto error;
941 }
942
943 err = bind_interdomain_evtchn_to_irq(dev->otherend_id, evtchn);
944 if (err < 0)
945 goto error;
946 fedata->irq = err;
947
948 err = request_threaded_irq(fedata->irq, NULL, pvcalls_back_event,
949 IRQF_ONESHOT, "pvcalls-back", dev);
950 if (err < 0)
951 goto error;
952
953 err = xenbus_map_ring_valloc(dev, &ring_ref, 1,
954 (void **)&fedata->sring);
955 if (err < 0)
956 goto error;
957
958 BACK_RING_INIT(&fedata->ring, fedata->sring, XEN_PAGE_SIZE * 1);
959 fedata->dev = dev;
960
961 INIT_LIST_HEAD(&fedata->socket_mappings);
962 INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL);
963 sema_init(&fedata->socket_lock, 1);
964 dev_set_drvdata(&dev->dev, fedata);
965
966 down(&pvcalls_back_global.frontends_lock);
967 list_add_tail(&fedata->list, &pvcalls_back_global.frontends);
968 up(&pvcalls_back_global.frontends_lock);
969
970 return 0;
971
972 error:
973 if (fedata->irq >= 0)
974 unbind_from_irqhandler(fedata->irq, dev);
975 if (fedata->sring != NULL)
976 xenbus_unmap_ring_vfree(dev, fedata->sring);
977 kfree(fedata);
978 return err;
979 }
980
981 static int backend_disconnect(struct xenbus_device *dev)
982 {
983 struct pvcalls_fedata *fedata;
984 struct sock_mapping *map, *n;
985 struct sockpass_mapping *mappass;
986 struct radix_tree_iter iter;
987 void **slot;
988
989
990 fedata = dev_get_drvdata(&dev->dev);
991
992 down(&fedata->socket_lock);
993 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {
994 list_del(&map->list);
995 pvcalls_back_release_active(dev, fedata, map);
996 }
997
998 radix_tree_for_each_slot(slot, &fedata->socketpass_mappings, &iter, 0) {
999 mappass = radix_tree_deref_slot(slot);
1000 if (!mappass)
1001 continue;
1002 if (radix_tree_exception(mappass)) {
1003 if (radix_tree_deref_retry(mappass))
1004 slot = radix_tree_iter_retry(&iter);
1005 } else {
1006 radix_tree_delete(&fedata->socketpass_mappings,
1007 mappass->id);
1008 pvcalls_back_release_passive(dev, fedata, mappass);
1009 }
1010 }
1011 up(&fedata->socket_lock);
1012
1013 unbind_from_irqhandler(fedata->irq, dev);
1014 xenbus_unmap_ring_vfree(dev, fedata->sring);
1015
1016 list_del(&fedata->list);
1017 kfree(fedata);
1018 dev_set_drvdata(&dev->dev, NULL);
1019
1020 return 0;
1021 }
1022
1023 static int pvcalls_back_probe(struct xenbus_device *dev,
1024 const struct xenbus_device_id *id)
1025 {
1026 int err, abort;
1027 struct xenbus_transaction xbt;
1028
1029 again:
1030 abort = 1;
1031
1032 err = xenbus_transaction_start(&xbt);
1033 if (err) {
1034 pr_warn("%s cannot create xenstore transaction\n", __func__);
1035 return err;
1036 }
1037
1038 err = xenbus_printf(xbt, dev->nodename, "versions", "%s",
1039 PVCALLS_VERSIONS);
1040 if (err) {
1041 pr_warn("%s write out 'versions' failed\n", __func__);
1042 goto abort;
1043 }
1044
1045 err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u",
1046 MAX_RING_ORDER);
1047 if (err) {
1048 pr_warn("%s write out 'max-page-order' failed\n", __func__);
1049 goto abort;
1050 }
1051
1052 err = xenbus_printf(xbt, dev->nodename, "function-calls",
1053 XENBUS_FUNCTIONS_CALLS);
1054 if (err) {
1055 pr_warn("%s write out 'function-calls' failed\n", __func__);
1056 goto abort;
1057 }
1058
1059 abort = 0;
1060 abort:
1061 err = xenbus_transaction_end(xbt, abort);
1062 if (err) {
1063 if (err == -EAGAIN && !abort)
1064 goto again;
1065 pr_warn("%s cannot complete xenstore transaction\n", __func__);
1066 return err;
1067 }
1068
1069 if (abort)
1070 return -EFAULT;
1071
1072 xenbus_switch_state(dev, XenbusStateInitWait);
1073
1074 return 0;
1075 }
1076
1077 static void set_backend_state(struct xenbus_device *dev,
1078 enum xenbus_state state)
1079 {
1080 while (dev->state != state) {
1081 switch (dev->state) {
1082 case XenbusStateClosed:
1083 switch (state) {
1084 case XenbusStateInitWait:
1085 case XenbusStateConnected:
1086 xenbus_switch_state(dev, XenbusStateInitWait);
1087 break;
1088 case XenbusStateClosing:
1089 xenbus_switch_state(dev, XenbusStateClosing);
1090 break;
1091 default:
1092 WARN_ON(1);
1093 }
1094 break;
1095 case XenbusStateInitWait:
1096 case XenbusStateInitialised:
1097 switch (state) {
1098 case XenbusStateConnected:
1099 if (backend_connect(dev))
1100 return;
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