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
pvcalls_conn_back_read(void * opaque)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 msg.msg_iter.type = ITER_KVEC|WRITE;
138 msg.msg_iter.count = wanted;
139 if (masked_prod < masked_cons) {
140 vec[0].iov_base = data->in + masked_prod;
141 vec[0].iov_len = wanted;
142 msg.msg_iter.kvec = vec;
143 msg.msg_iter.nr_segs = 1;
144 } else {
145 vec[0].iov_base = data->in + masked_prod;
146 vec[0].iov_len = array_size - masked_prod;
147 vec[1].iov_base = data->in;
148 vec[1].iov_len = wanted - vec[0].iov_len;
149 msg.msg_iter.kvec = vec;
150 msg.msg_iter.nr_segs = 2;
151 }
152
153 atomic_set(&map->read, 0);
154 ret = inet_recvmsg(map->sock, &msg, wanted, MSG_DONTWAIT);
155 WARN_ON(ret > wanted);
156 if (ret == -EAGAIN) /* shouldn't happen */
157 return;
158 if (!ret)
159 ret = -ENOTCONN;
160 spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags);
161 if (ret > 0 && !skb_queue_empty(&map->sock->sk->sk_receive_queue))
162 atomic_inc(&map->read);
163 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags);
164
165 /* write the data, then modify the indexes */
166 virt_wmb();
167 if (ret < 0) {
168 atomic_set(&map->read, 0);
169 intf->in_error = ret;
170 } else
171 intf->in_prod = prod + ret;
172 /* update the indexes, then notify the other end */
173 virt_wmb();
174 notify_remote_via_irq(map->irq);
175
176 return;
177 }
178
pvcalls_conn_back_write(struct sock_mapping * map)179 static void pvcalls_conn_back_write(struct sock_mapping *map)
180 {
181 struct pvcalls_data_intf *intf = map->ring;
182 struct pvcalls_data *data = &map->data;
183 struct msghdr msg;
184 struct kvec vec[2];
185 RING_IDX cons, prod, size, array_size;
186 int ret;
187
188 cons = intf->out_cons;
189 prod = intf->out_prod;
190 /* read the indexes before dealing with the data */
191 virt_mb();
192
193 array_size = XEN_FLEX_RING_SIZE(map->ring_order);
194 size = pvcalls_queued(prod, cons, array_size);
195 if (size == 0)
196 return;
197
198 memset(&msg, 0, sizeof(msg));
199 msg.msg_flags |= MSG_DONTWAIT;
200 msg.msg_iter.type = ITER_KVEC|READ;
201 msg.msg_iter.count = size;
202 if (pvcalls_mask(prod, array_size) > pvcalls_mask(cons, array_size)) {
203 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
204 vec[0].iov_len = size;
205 msg.msg_iter.kvec = vec;
206 msg.msg_iter.nr_segs = 1;
207 } else {
208 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
209 vec[0].iov_len = array_size - pvcalls_mask(cons, array_size);
210 vec[1].iov_base = data->out;
211 vec[1].iov_len = size - vec[0].iov_len;
212 msg.msg_iter.kvec = vec;
213 msg.msg_iter.nr_segs = 2;
214 }
215
216 atomic_set(&map->write, 0);
217 ret = inet_sendmsg(map->sock, &msg, size);
218 if (ret == -EAGAIN || (ret >= 0 && ret < size)) {
219 atomic_inc(&map->write);
220 atomic_inc(&map->io);
221 }
222 if (ret == -EAGAIN)
223 return;
224
225 /* write the data, then update the indexes */
226 virt_wmb();
227 if (ret < 0) {
228 intf->out_error = ret;
229 } else {
230 intf->out_error = 0;
231 intf->out_cons = cons + ret;
232 prod = intf->out_prod;
233 }
234 /* update the indexes, then notify the other end */
235 virt_wmb();
236 if (prod != cons + ret)
237 atomic_inc(&map->write);
238 notify_remote_via_irq(map->irq);
239 }
240
pvcalls_back_ioworker(struct work_struct * work)241 static void pvcalls_back_ioworker(struct work_struct *work)
242 {
243 struct pvcalls_ioworker *ioworker = container_of(work,
244 struct pvcalls_ioworker, register_work);
245 struct sock_mapping *map = container_of(ioworker, struct sock_mapping,
246 ioworker);
247
248 while (atomic_read(&map->io) > 0) {
249 if (atomic_read(&map->release) > 0) {
250 atomic_set(&map->release, 0);
251 return;
252 }
253
254 if (atomic_read(&map->read) > 0)
255 pvcalls_conn_back_read(map);
256 if (atomic_read(&map->write) > 0)
257 pvcalls_conn_back_write(map);
258
259 atomic_dec(&map->io);
260 }
261 }
262
pvcalls_back_socket(struct xenbus_device * dev,struct xen_pvcalls_request * req)263 static int pvcalls_back_socket(struct xenbus_device *dev,
264 struct xen_pvcalls_request *req)
265 {
266 struct pvcalls_fedata *fedata;
267 int ret;
268 struct xen_pvcalls_response *rsp;
269
270 fedata = dev_get_drvdata(&dev->dev);
271
272 if (req->u.socket.domain != AF_INET ||
273 req->u.socket.type != SOCK_STREAM ||
274 (req->u.socket.protocol != IPPROTO_IP &&
275 req->u.socket.protocol != AF_INET))
276 ret = -EAFNOSUPPORT;
277 else
278 ret = 0;
279
280 /* leave the actual socket allocation for later */
281
282 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
283 rsp->req_id = req->req_id;
284 rsp->cmd = req->cmd;
285 rsp->u.socket.id = req->u.socket.id;
286 rsp->ret = ret;
287
288 return 0;
289 }
290
pvcalls_sk_state_change(struct sock * sock)291 static void pvcalls_sk_state_change(struct sock *sock)
292 {
293 struct sock_mapping *map = sock->sk_user_data;
294
295 if (map == NULL)
296 return;
297
298 atomic_inc(&map->read);
299 notify_remote_via_irq(map->irq);
300 }
301
pvcalls_sk_data_ready(struct sock * sock)302 static void pvcalls_sk_data_ready(struct sock *sock)
303 {
304 struct sock_mapping *map = sock->sk_user_data;
305 struct pvcalls_ioworker *iow;
306
307 if (map == NULL)
308 return;
309
310 iow = &map->ioworker;
311 atomic_inc(&map->read);
312 atomic_inc(&map->io);
313 queue_work(iow->wq, &iow->register_work);
314 }
315
pvcalls_new_active_socket(struct pvcalls_fedata * fedata,uint64_t id,grant_ref_t ref,uint32_t evtchn,struct socket * sock)316 static struct sock_mapping *pvcalls_new_active_socket(
317 struct pvcalls_fedata *fedata,
318 uint64_t id,
319 grant_ref_t ref,
320 uint32_t evtchn,
321 struct socket *sock)
322 {
323 int ret;
324 struct sock_mapping *map;
325 void *page;
326
327 map = kzalloc(sizeof(*map), GFP_KERNEL);
328 if (map == NULL)
329 return NULL;
330
331 map->fedata = fedata;
332 map->sock = sock;
333 map->id = id;
334 map->ref = ref;
335
336 ret = xenbus_map_ring_valloc(fedata->dev, &ref, 1, &page);
337 if (ret < 0)
338 goto out;
339 map->ring = page;
340 map->ring_order = map->ring->ring_order;
341 /* first read the order, then map the data ring */
342 virt_rmb();
343 if (map->ring_order > MAX_RING_ORDER) {
344 pr_warn("%s frontend requested ring_order %u, which is > MAX (%u)\n",
345 __func__, map->ring_order, MAX_RING_ORDER);
346 goto out;
347 }
348 ret = xenbus_map_ring_valloc(fedata->dev, map->ring->ref,
349 (1 << map->ring_order), &page);
350 if (ret < 0)
351 goto out;
352 map->bytes = page;
353
354 ret = bind_interdomain_evtchn_to_irqhandler(fedata->dev->otherend_id,
355 evtchn,
356 pvcalls_back_conn_event,
357 0,
358 "pvcalls-backend",
359 map);
360 if (ret < 0)
361 goto out;
362 map->irq = ret;
363
364 map->data.in = map->bytes;
365 map->data.out = map->bytes + XEN_FLEX_RING_SIZE(map->ring_order);
366
367 map->ioworker.wq = alloc_workqueue("pvcalls_io", WQ_UNBOUND, 1);
368 if (!map->ioworker.wq)
369 goto out;
370 atomic_set(&map->io, 1);
371 INIT_WORK(&map->ioworker.register_work, pvcalls_back_ioworker);
372
373 down(&fedata->socket_lock);
374 list_add_tail(&map->list, &fedata->socket_mappings);
375 up(&fedata->socket_lock);
376
377 write_lock_bh(&map->sock->sk->sk_callback_lock);
378 map->saved_data_ready = map->sock->sk->sk_data_ready;
379 map->sock->sk->sk_user_data = map;
380 map->sock->sk->sk_data_ready = pvcalls_sk_data_ready;
381 map->sock->sk->sk_state_change = pvcalls_sk_state_change;
382 write_unlock_bh(&map->sock->sk->sk_callback_lock);
383
384 return map;
385 out:
386 down(&fedata->socket_lock);
387 list_del(&map->list);
388 pvcalls_back_release_active(fedata->dev, fedata, map);
389 up(&fedata->socket_lock);
390 return NULL;
391 }
392
pvcalls_back_connect(struct xenbus_device * dev,struct xen_pvcalls_request * req)393 static int pvcalls_back_connect(struct xenbus_device *dev,
394 struct xen_pvcalls_request *req)
395 {
396 struct pvcalls_fedata *fedata;
397 int ret = -EINVAL;
398 struct socket *sock;
399 struct sock_mapping *map;
400 struct xen_pvcalls_response *rsp;
401 struct sockaddr *sa = (struct sockaddr *)&req->u.connect.addr;
402
403 fedata = dev_get_drvdata(&dev->dev);
404
405 if (req->u.connect.len < sizeof(sa->sa_family) ||
406 req->u.connect.len > sizeof(req->u.connect.addr) ||
407 sa->sa_family != AF_INET)
408 goto out;
409
410 ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock);
411 if (ret < 0)
412 goto out;
413 ret = inet_stream_connect(sock, sa, req->u.connect.len, 0);
414 if (ret < 0) {
415 sock_release(sock);
416 goto out;
417 }
418
419 map = pvcalls_new_active_socket(fedata,
420 req->u.connect.id,
421 req->u.connect.ref,
422 req->u.connect.evtchn,
423 sock);
424 if (!map) {
425 ret = -EFAULT;
426 sock_release(sock);
427 }
428
429 out:
430 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
431 rsp->req_id = req->req_id;
432 rsp->cmd = req->cmd;
433 rsp->u.connect.id = req->u.connect.id;
434 rsp->ret = ret;
435
436 return 0;
437 }
438
pvcalls_back_release_active(struct xenbus_device * dev,struct pvcalls_fedata * fedata,struct sock_mapping * map)439 static int pvcalls_back_release_active(struct xenbus_device *dev,
440 struct pvcalls_fedata *fedata,
441 struct sock_mapping *map)
442 {
443 disable_irq(map->irq);
444 if (map->sock->sk != NULL) {
445 write_lock_bh(&map->sock->sk->sk_callback_lock);
446 map->sock->sk->sk_user_data = NULL;
447 map->sock->sk->sk_data_ready = map->saved_data_ready;
448 write_unlock_bh(&map->sock->sk->sk_callback_lock);
449 }
450
451 atomic_set(&map->release, 1);
452 flush_work(&map->ioworker.register_work);
453
454 xenbus_unmap_ring_vfree(dev, map->bytes);
455 xenbus_unmap_ring_vfree(dev, (void *)map->ring);
456 unbind_from_irqhandler(map->irq, map);
457
458 sock_release(map->sock);
459 kfree(map);
460
461 return 0;
462 }
463
pvcalls_back_release_passive(struct xenbus_device * dev,struct pvcalls_fedata * fedata,struct sockpass_mapping * mappass)464 static int pvcalls_back_release_passive(struct xenbus_device *dev,
465 struct pvcalls_fedata *fedata,
466 struct sockpass_mapping *mappass)
467 {
468 if (mappass->sock->sk != NULL) {
469 write_lock_bh(&mappass->sock->sk->sk_callback_lock);
470 mappass->sock->sk->sk_user_data = NULL;
471 mappass->sock->sk->sk_data_ready = mappass->saved_data_ready;
472 write_unlock_bh(&mappass->sock->sk->sk_callback_lock);
473 }
474 sock_release(mappass->sock);
475 flush_workqueue(mappass->wq);
476 destroy_workqueue(mappass->wq);
477 kfree(mappass);
478
479 return 0;
480 }
481
pvcalls_back_release(struct xenbus_device * dev,struct xen_pvcalls_request * req)482 static int pvcalls_back_release(struct xenbus_device *dev,
483 struct xen_pvcalls_request *req)
484 {
485 struct pvcalls_fedata *fedata;
486 struct sock_mapping *map, *n;
487 struct sockpass_mapping *mappass;
488 int ret = 0;
489 struct xen_pvcalls_response *rsp;
490
491 fedata = dev_get_drvdata(&dev->dev);
492
493 down(&fedata->socket_lock);
494 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {
495 if (map->id == req->u.release.id) {
496 list_del(&map->list);
497 up(&fedata->socket_lock);
498 ret = pvcalls_back_release_active(dev, fedata, map);
499 goto out;
500 }
501 }
502 mappass = radix_tree_lookup(&fedata->socketpass_mappings,
503 req->u.release.id);
504 if (mappass != NULL) {
505 radix_tree_delete(&fedata->socketpass_mappings, mappass->id);
506 up(&fedata->socket_lock);
507 ret = pvcalls_back_release_passive(dev, fedata, mappass);
508 } else
509 up(&fedata->socket_lock);
510
511 out:
512 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
513 rsp->req_id = req->req_id;
514 rsp->u.release.id = req->u.release.id;
515 rsp->cmd = req->cmd;
516 rsp->ret = ret;
517 return 0;
518 }
519
__pvcalls_back_accept(struct work_struct * work)520 static void __pvcalls_back_accept(struct work_struct *work)
521 {
522 struct sockpass_mapping *mappass = container_of(
523 work, struct sockpass_mapping, register_work);
524 struct sock_mapping *map;
525 struct pvcalls_ioworker *iow;
526 struct pvcalls_fedata *fedata;
527 struct socket *sock;
528 struct xen_pvcalls_response *rsp;
529 struct xen_pvcalls_request *req;
530 int notify;
531 int ret = -EINVAL;
532 unsigned long flags;
533
534 fedata = mappass->fedata;
535 /*
536 * __pvcalls_back_accept can race against pvcalls_back_accept.
537 * We only need to check the value of "cmd" on read. It could be
538 * done atomically, but to simplify the code on the write side, we
539 * use a spinlock.
540 */
541 spin_lock_irqsave(&mappass->copy_lock, flags);
542 req = &mappass->reqcopy;
543 if (req->cmd != PVCALLS_ACCEPT) {
544 spin_unlock_irqrestore(&mappass->copy_lock, flags);
545 return;
546 }
547 spin_unlock_irqrestore(&mappass->copy_lock, flags);
548
549 sock = sock_alloc();
550 if (sock == NULL)
551 goto out_error;
552 sock->type = mappass->sock->type;
553 sock->ops = mappass->sock->ops;
554
555 ret = inet_accept(mappass->sock, sock, O_NONBLOCK, true);
556 if (ret == -EAGAIN) {
557 sock_release(sock);
558 goto out_error;
559 }
560
561 map = pvcalls_new_active_socket(fedata,
562 req->u.accept.id_new,
563 req->u.accept.ref,
564 req->u.accept.evtchn,
565 sock);
566 if (!map) {
567 ret = -EFAULT;
568 sock_release(sock);
569 goto out_error;
570 }
571
572 map->sockpass = mappass;
573 iow = &map->ioworker;
574 atomic_inc(&map->read);
575 atomic_inc(&map->io);
576 queue_work(iow->wq, &iow->register_work);
577
578 out_error:
579 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
580 rsp->req_id = req->req_id;
581 rsp->cmd = req->cmd;
582 rsp->u.accept.id = req->u.accept.id;
583 rsp->ret = ret;
584 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);
585 if (notify)
586 notify_remote_via_irq(fedata->irq);
587
588 mappass->reqcopy.cmd = 0;
589 }
590
pvcalls_pass_sk_data_ready(struct sock * sock)591 static void pvcalls_pass_sk_data_ready(struct sock *sock)
592 {
593 struct sockpass_mapping *mappass = sock->sk_user_data;
594 struct pvcalls_fedata *fedata;
595 struct xen_pvcalls_response *rsp;
596 unsigned long flags;
597 int notify;
598
599 if (mappass == NULL)
600 return;
601
602 fedata = mappass->fedata;
603 spin_lock_irqsave(&mappass->copy_lock, flags);
604 if (mappass->reqcopy.cmd == PVCALLS_POLL) {
605 rsp = RING_GET_RESPONSE(&fedata->ring,
606 fedata->ring.rsp_prod_pvt++);
607 rsp->req_id = mappass->reqcopy.req_id;
608 rsp->u.poll.id = mappass->reqcopy.u.poll.id;
609 rsp->cmd = mappass->reqcopy.cmd;
610 rsp->ret = 0;
611
612 mappass->reqcopy.cmd = 0;
613 spin_unlock_irqrestore(&mappass->copy_lock, flags);
614
615 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);
616 if (notify)
617 notify_remote_via_irq(mappass->fedata->irq);
618 } else {
619 spin_unlock_irqrestore(&mappass->copy_lock, flags);
620 queue_work(mappass->wq, &mappass->register_work);
621 }
622 }
623
pvcalls_back_bind(struct xenbus_device * dev,struct xen_pvcalls_request * req)624 static int pvcalls_back_bind(struct xenbus_device *dev,
625 struct xen_pvcalls_request *req)
626 {
627 struct pvcalls_fedata *fedata;
628 int ret;
629 struct sockpass_mapping *map;
630 struct xen_pvcalls_response *rsp;
631
632 fedata = dev_get_drvdata(&dev->dev);
633
634 map = kzalloc(sizeof(*map), GFP_KERNEL);
635 if (map == NULL) {
636 ret = -ENOMEM;
637 goto out;
638 }
639
640 INIT_WORK(&map->register_work, __pvcalls_back_accept);
641 spin_lock_init(&map->copy_lock);
642 map->wq = alloc_workqueue("pvcalls_wq", WQ_UNBOUND, 1);
643 if (!map->wq) {
644 ret = -ENOMEM;
645 goto out;
646 }
647
648 ret = sock_create(AF_INET, SOCK_STREAM, 0, &map->sock);
649 if (ret < 0)
650 goto out;
651
652 ret = inet_bind(map->sock, (struct sockaddr *)&req->u.bind.addr,
653 req->u.bind.len);
654 if (ret < 0)
655 goto out;
656
657 map->fedata = fedata;
658 map->id = req->u.bind.id;
659
660 down(&fedata->socket_lock);
661 ret = radix_tree_insert(&fedata->socketpass_mappings, map->id,
662 map);
663 up(&fedata->socket_lock);
664 if (ret)
665 goto out;
666
667 write_lock_bh(&map->sock->sk->sk_callback_lock);
668 map->saved_data_ready = map->sock->sk->sk_data_ready;
669 map->sock->sk->sk_user_data = map;
670 map->sock->sk->sk_data_ready = pvcalls_pass_sk_data_ready;
671 write_unlock_bh(&map->sock->sk->sk_callback_lock);
672
673 out:
674 if (ret) {
675 if (map && map->sock)
676 sock_release(map->sock);
677 if (map && map->wq)
678 destroy_workqueue(map->wq);
679 kfree(map);
680 }
681 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
682 rsp->req_id = req->req_id;
683 rsp->cmd = req->cmd;
684 rsp->u.bind.id = req->u.bind.id;
685 rsp->ret = ret;
686 return 0;
687 }
688
pvcalls_back_listen(struct xenbus_device * dev,struct xen_pvcalls_request * req)689 static int pvcalls_back_listen(struct xenbus_device *dev,
690 struct xen_pvcalls_request *req)
691 {
692 struct pvcalls_fedata *fedata;
693 int ret = -EINVAL;
694 struct sockpass_mapping *map;
695 struct xen_pvcalls_response *rsp;
696
697 fedata = dev_get_drvdata(&dev->dev);
698
699 down(&fedata->socket_lock);
700 map = radix_tree_lookup(&fedata->socketpass_mappings, req->u.listen.id);
701 up(&fedata->socket_lock);
702 if (map == NULL)
703 goto out;
704
705 ret = inet_listen(map->sock, req->u.listen.backlog);
706
707 out:
708 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
709 rsp->req_id = req->req_id;
710 rsp->cmd = req->cmd;
711 rsp->u.listen.id = req->u.listen.id;
712 rsp->ret = ret;
713 return 0;
714 }
715
pvcalls_back_accept(struct xenbus_device * dev,struct xen_pvcalls_request * req)716 static int pvcalls_back_accept(struct xenbus_device *dev,
717 struct xen_pvcalls_request *req)
718 {
719 struct pvcalls_fedata *fedata;
720 struct sockpass_mapping *mappass;
721 int ret = -EINVAL;
722 struct xen_pvcalls_response *rsp;
723 unsigned long flags;
724
725 fedata = dev_get_drvdata(&dev->dev);
726
727 down(&fedata->socket_lock);
728 mappass = radix_tree_lookup(&fedata->socketpass_mappings,
729 req->u.accept.id);
730 up(&fedata->socket_lock);
731 if (mappass == NULL)
732 goto out_error;
733
734 /*
735 * Limitation of the current implementation: only support one
736 * concurrent accept or poll call on one socket.
737 */
738 spin_lock_irqsave(&mappass->copy_lock, flags);
739 if (mappass->reqcopy.cmd != 0) {
740 spin_unlock_irqrestore(&mappass->copy_lock, flags);
741 ret = -EINTR;
742 goto out_error;
743 }
744
745 mappass->reqcopy = *req;
746 spin_unlock_irqrestore(&mappass->copy_lock, flags);
747 queue_work(mappass->wq, &mappass->register_work);
748
749 /* Tell the caller we don't need to send back a notification yet */
750 return -1;
751
752 out_error:
753 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
754 rsp->req_id = req->req_id;
755 rsp->cmd = req->cmd;
756 rsp->u.accept.id = req->u.accept.id;
757 rsp->ret = ret;
758 return 0;
759 }
760
pvcalls_back_poll(struct xenbus_device * dev,struct xen_pvcalls_request * req)761 static int pvcalls_back_poll(struct xenbus_device *dev,
762 struct xen_pvcalls_request *req)
763 {
764 struct pvcalls_fedata *fedata;
765 struct sockpass_mapping *mappass;
766 struct xen_pvcalls_response *rsp;
767 struct inet_connection_sock *icsk;
768 struct request_sock_queue *queue;
769 unsigned long flags;
770 int ret;
771 bool data;
772
773 fedata = dev_get_drvdata(&dev->dev);
774
775 down(&fedata->socket_lock);
776 mappass = radix_tree_lookup(&fedata->socketpass_mappings,
777 req->u.poll.id);
778 up(&fedata->socket_lock);
779 if (mappass == NULL)
780 return -EINVAL;
781
782 /*
783 * Limitation of the current implementation: only support one
784 * concurrent accept or poll call on one socket.
785 */
786 spin_lock_irqsave(&mappass->copy_lock, flags);
787 if (mappass->reqcopy.cmd != 0) {
788 ret = -EINTR;
789 goto out;
790 }
791
792 mappass->reqcopy = *req;
793 icsk = inet_csk(mappass->sock->sk);
794 queue = &icsk->icsk_accept_queue;
795 data = READ_ONCE(queue->rskq_accept_head) != NULL;
796 if (data) {
797 mappass->reqcopy.cmd = 0;
798 ret = 0;
799 goto out;
800 }
801 spin_unlock_irqrestore(&mappass->copy_lock, flags);
802
803 /* Tell the caller we don't need to send back a notification yet */
804 return -1;
805
806 out:
807 spin_unlock_irqrestore(&mappass->copy_lock, flags);
808
809 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
810 rsp->req_id = req->req_id;
811 rsp->cmd = req->cmd;
812 rsp->u.poll.id = req->u.poll.id;
813 rsp->ret = ret;
814 return 0;
815 }
816
pvcalls_back_handle_cmd(struct xenbus_device * dev,struct xen_pvcalls_request * req)817 static int pvcalls_back_handle_cmd(struct xenbus_device *dev,
818 struct xen_pvcalls_request *req)
819 {
820 int ret = 0;
821
822 switch (req->cmd) {
823 case PVCALLS_SOCKET:
824 ret = pvcalls_back_socket(dev, req);
825 break;
826 case PVCALLS_CONNECT:
827 ret = pvcalls_back_connect(dev, req);
828 break;
829 case PVCALLS_RELEASE:
830 ret = pvcalls_back_release(dev, req);
831 break;
832 case PVCALLS_BIND:
833 ret = pvcalls_back_bind(dev, req);
834 break;
835 case PVCALLS_LISTEN:
836 ret = pvcalls_back_listen(dev, req);
837 break;
838 case PVCALLS_ACCEPT:
839 ret = pvcalls_back_accept(dev, req);
840 break;
841 case PVCALLS_POLL:
842 ret = pvcalls_back_poll(dev, req);
843 break;
844 default:
845 {
846 struct pvcalls_fedata *fedata;
847 struct xen_pvcalls_response *rsp;
848
849 fedata = dev_get_drvdata(&dev->dev);
850 rsp = RING_GET_RESPONSE(
851 &fedata->ring, fedata->ring.rsp_prod_pvt++);
852 rsp->req_id = req->req_id;
853 rsp->cmd = req->cmd;
854 rsp->ret = -ENOTSUPP;
855 break;
856 }
857 }
858 return ret;
859 }
860
pvcalls_back_work(struct pvcalls_fedata * fedata)861 static void pvcalls_back_work(struct pvcalls_fedata *fedata)
862 {
863 int notify, notify_all = 0, more = 1;
864 struct xen_pvcalls_request req;
865 struct xenbus_device *dev = fedata->dev;
866
867 while (more) {
868 while (RING_HAS_UNCONSUMED_REQUESTS(&fedata->ring)) {
869 RING_COPY_REQUEST(&fedata->ring,
870 fedata->ring.req_cons++,
871 &req);
872
873 if (!pvcalls_back_handle_cmd(dev, &req)) {
874 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(
875 &fedata->ring, notify);
876 notify_all += notify;
877 }
878 }
879
880 if (notify_all) {
881 notify_remote_via_irq(fedata->irq);
882 notify_all = 0;
883 }
884
885 RING_FINAL_CHECK_FOR_REQUESTS(&fedata->ring, more);
886 }
887 }
888
pvcalls_back_event(int irq,void * dev_id)889 static irqreturn_t pvcalls_back_event(int irq, void *dev_id)
890 {
891 struct xenbus_device *dev = dev_id;
892 struct pvcalls_fedata *fedata = NULL;
893
894 if (dev == NULL)
895 return IRQ_HANDLED;
896
897 fedata = dev_get_drvdata(&dev->dev);
898 if (fedata == NULL)
899 return IRQ_HANDLED;
900
901 pvcalls_back_work(fedata);
902 return IRQ_HANDLED;
903 }
904
pvcalls_back_conn_event(int irq,void * sock_map)905 static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map)
906 {
907 struct sock_mapping *map = sock_map;
908 struct pvcalls_ioworker *iow;
909
910 if (map == NULL || map->sock == NULL || map->sock->sk == NULL ||
911 map->sock->sk->sk_user_data != map)
912 return IRQ_HANDLED;
913
914 iow = &map->ioworker;
915
916 atomic_inc(&map->write);
917 atomic_inc(&map->io);
918 queue_work(iow->wq, &iow->register_work);
919
920 return IRQ_HANDLED;
921 }
922
backend_connect(struct xenbus_device * dev)923 static int backend_connect(struct xenbus_device *dev)
924 {
925 int err, evtchn;
926 grant_ref_t ring_ref;
927 struct pvcalls_fedata *fedata = NULL;
928
929 fedata = kzalloc(sizeof(struct pvcalls_fedata), GFP_KERNEL);
930 if (!fedata)
931 return -ENOMEM;
932
933 fedata->irq = -1;
934 err = xenbus_scanf(XBT_NIL, dev->otherend, "port", "%u",
935 &evtchn);
936 if (err != 1) {
937 err = -EINVAL;
938 xenbus_dev_fatal(dev, err, "reading %s/event-channel",
939 dev->otherend);
940 goto error;
941 }
942
943 err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", "%u", &ring_ref);
944 if (err != 1) {
945 err = -EINVAL;
946 xenbus_dev_fatal(dev, err, "reading %s/ring-ref",
947 dev->otherend);
948 goto error;
949 }
950
951 err = bind_interdomain_evtchn_to_irq(dev->otherend_id, evtchn);
952 if (err < 0)
953 goto error;
954 fedata->irq = err;
955
956 err = request_threaded_irq(fedata->irq, NULL, pvcalls_back_event,
957 IRQF_ONESHOT, "pvcalls-back", dev);
958 if (err < 0)
959 goto error;
960
961 err = xenbus_map_ring_valloc(dev, &ring_ref, 1,
962 (void **)&fedata->sring);
963 if (err < 0)
964 goto error;
965
966 BACK_RING_INIT(&fedata->ring, fedata->sring, XEN_PAGE_SIZE * 1);
967 fedata->dev = dev;
968
969 INIT_LIST_HEAD(&fedata->socket_mappings);
970 INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL);
971 sema_init(&fedata->socket_lock, 1);
972 dev_set_drvdata(&dev->dev, fedata);
973
974 down(&pvcalls_back_global.frontends_lock);
975 list_add_tail(&fedata->list, &pvcalls_back_global.frontends);
976 up(&pvcalls_back_global.frontends_lock);
977
978 return 0;
979
980 error:
981 if (fedata->irq >= 0)
982 unbind_from_irqhandler(fedata->irq, dev);
983 if (fedata->sring != NULL)
984 xenbus_unmap_ring_vfree(dev, fedata->sring);
985 kfree(fedata);
986 return err;
987 }
988
backend_disconnect(struct xenbus_device * dev)989 static int backend_disconnect(struct xenbus_device *dev)
990 {
991 struct pvcalls_fedata *fedata;
992 struct sock_mapping *map, *n;
993 struct sockpass_mapping *mappass;
994 struct radix_tree_iter iter;
995 void **slot;
996
997
998 fedata = dev_get_drvdata(&dev->dev);
999
1000 down(&fedata->socket_lock);
1001 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {
1002 list_del(&map->list);
1003 pvcalls_back_release_active(dev, fedata, map);
1004 }
1005
1006 radix_tree_for_each_slot(slot, &fedata->socketpass_mappings, &iter, 0) {
1007 mappass = radix_tree_deref_slot(slot);
1008 if (!mappass)
1009 continue;
1010 if (radix_tree_exception(mappass)) {
1011 if (radix_tree_deref_retry(mappass))
1012 slot = radix_tree_iter_retry(&iter);
1013 } else {
1014 radix_tree_delete(&fedata->socketpass_mappings,
1015 mappass->id);
1016 pvcalls_back_release_passive(dev, fedata, mappass);
1017 }
1018 }
1019 up(&fedata->socket_lock);
1020
1021 unbind_from_irqhandler(fedata->irq, dev);
1022 xenbus_unmap_ring_vfree(dev, fedata->sring);
1023
1024 list_del(&fedata->list);
1025 kfree(fedata);
1026 dev_set_drvdata(&dev->dev, NULL);
1027
1028 return 0;
1029 }
1030
pvcalls_back_probe(struct xenbus_device * dev,const struct xenbus_device_id * id)1031 static int pvcalls_back_probe(struct xenbus_device *dev,
1032 const struct xenbus_device_id *id)
1033 {
1034 int err, abort;
1035 struct xenbus_transaction xbt;
1036
1037 again:
1038 abort = 1;
1039
1040 err = xenbus_transaction_start(&xbt);
1041 if (err) {
1042 pr_warn("%s cannot create xenstore transaction\n", __func__);
1043 return err;
1044 }
1045
1046 err = xenbus_printf(xbt, dev->nodename, "versions", "%s",
1047 PVCALLS_VERSIONS);
1048 if (err) {
1049 pr_warn("%s write out 'versions' failed\n", __func__);
1050 goto abort;
1051 }
1052
1053 err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u",
1054 MAX_RING_ORDER);
1055 if (err) {
1056 pr_warn("%s write out 'max-page-order' failed\n", __func__);
1057 goto abort;
1058 }
1059
1060 err = xenbus_printf(xbt, dev->nodename, "function-calls",
1061 XENBUS_FUNCTIONS_CALLS);
1062 if (err) {
1063 pr_warn("%s write out 'function-calls' failed\n", __func__);
1064 goto abort;
1065 }
1066
1067 abort = 0;
1068 abort:
1069 err = xenbus_transaction_end(xbt, abort);
1070 if (err) {
1071 if (err == -EAGAIN && !abort)
1072 goto again;
1073 pr_warn("%s cannot complete xenstore transaction\n", __func__);
1074 return err;
1075 }
1076
1077 if (abort)
1078 return -EFAULT;
1079
1080 xenbus_switch_state(dev, XenbusStateInitWait);
1081
1082 return 0;
1083 }
1084
set_backend_state(struct xenbus_device * dev,enum xenbus_state state)1085 static void set_backend_state(struct xenbus_device *dev,
1086 enum xenbus_state state)
1087 {
1088 while (dev->state != state) {
1089 switch (dev->state) {
1090 case XenbusStateClosed:
1091 switch (state) {
1092 case XenbusStateInitWait:
1093 case XenbusStateConnected:
1094 xenbus_switch_state(dev, XenbusStateInitWait);
1095 break;
1096 case XenbusStateClosing:
1097 xenbus_switch_state(dev, XenbusStateClosing);
1098 break;
1099 default:
1100 WARN_ON(1);
1101 }
1102 break;
1103 case XenbusStateInitWait:
1104 case XenbusStateInitialised:
1105 switch (state) {
1106 case XenbusStateConnected:
1107 backend_connect(dev);
1108 xenbus_switch_state(dev, XenbusStateConnected);
1109 break;
1110 case XenbusStateClosing:
1111 case XenbusStateClosed:
1112 xenbus_switch_state(dev, XenbusStateClosing);
1113 break;
1114 default:
1115 WARN_ON(1);
1116 }
1117 break;
1118 case XenbusStateConnected:
1119 switch (state) {
1120 case XenbusStateInitWait:
1121 case XenbusStateClosing:
1122 case XenbusStateClosed:
1123 down(&pvcalls_back_global.frontends_lock);
1124 backend_disconnect(dev);
1125 up(&pvcalls_back_global.frontends_lock);
1126 xenbus_switch_state(dev, XenbusStateClosing);
1127 break;
1128 default:
1129 WARN_ON(1);
1130 }
1131 break;
1132 case XenbusStateClosing:
1133 switch (state) {
1134 case XenbusStateInitWait:
1135 case XenbusStateConnected:
1136 case XenbusStateClosed:
1137 xenbus_switch_state(dev, XenbusStateClosed);
1138 break;
1139 default:
1140 WARN_ON(1);
1141 }
1142 break;
1143 default:
1144 WARN_ON(1);
1145 }
1146 }
1147 }
1148
pvcalls_back_changed(struct xenbus_device * dev,enum xenbus_state frontend_state)1149 static void pvcalls_back_changed(struct xenbus_device *dev,
1150 enum xenbus_state frontend_state)
1151 {
1152 switch (frontend_state) {
1153 case XenbusStateInitialising:
1154 set_backend_state(dev, XenbusStateInitWait);
1155 break;
1156
1157 case XenbusStateInitialised:
1158 case XenbusStateConnected:
1159 set_backend_state(dev, XenbusStateConnected);
1160 break;
1161
1162 case XenbusStateClosing:
1163 set_backend_state(dev, XenbusStateClosing);
1164 break;
1165
1166 case XenbusStateClosed:
1167 set_backend_state(dev, XenbusStateClosed);
1168 if (xenbus_dev_is_online(dev))
1169 break;
1170 device_unregister(&dev->dev);
1171 break;
1172 case XenbusStateUnknown:
1173 set_backend_state(dev, XenbusStateClosed);
1174 device_unregister(&dev->dev);
1175 break;
1176
1177 default:
1178 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1179 frontend_state);
1180 break;
1181 }
1182 }
1183
pvcalls_back_remove(struct xenbus_device * dev)1184 static int pvcalls_back_remove(struct xenbus_device *dev)
1185 {
1186 return 0;
1187 }
1188
pvcalls_back_uevent(struct xenbus_device * xdev,struct kobj_uevent_env * env)1189 static int pvcalls_back_uevent(struct xenbus_device *xdev,
1190 struct kobj_uevent_env *env)
1191 {
1192 return 0;
1193 }
1194
1195 static const struct xenbus_device_id pvcalls_back_ids[] = {
1196 { "pvcalls" },
1197 { "" }
1198 };
1199
1200 static struct xenbus_driver pvcalls_back_driver = {
1201 .ids = pvcalls_back_ids,
1202 .probe = pvcalls_back_probe,
1203 .remove = pvcalls_back_remove,
1204 .uevent = pvcalls_back_uevent,
1205 .otherend_changed = pvcalls_back_changed,
1206 };
1207
pvcalls_back_init(void)1208 static int __init pvcalls_back_init(void)
1209 {
1210 int ret;
1211
1212 if (!xen_domain())
1213 return -ENODEV;
1214
1215 ret = xenbus_register_backend(&pvcalls_back_driver);
1216 if (ret < 0)
1217 return ret;
1218
1219 sema_init(&pvcalls_back_global.frontends_lock, 1);
1220 INIT_LIST_HEAD(&pvcalls_back_global.frontends);
1221 return 0;
1222 }
1223 module_init(pvcalls_back_init);
1224
pvcalls_back_fin(void)1225 static void __exit pvcalls_back_fin(void)
1226 {
1227 struct pvcalls_fedata *fedata, *nfedata;
1228
1229 down(&pvcalls_back_global.frontends_lock);
1230 list_for_each_entry_safe(fedata, nfedata,
1231 &pvcalls_back_global.frontends, list) {
1232 backend_disconnect(fedata->dev);
1233 }
1234 up(&pvcalls_back_global.frontends_lock);
1235
1236 xenbus_unregister_driver(&pvcalls_back_driver);
1237 }
1238
1239 module_exit(pvcalls_back_fin);
1240