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 atomic_t eoi;
79 void (*saved_data_ready)(struct sock *sk);
80 struct pvcalls_ioworker ioworker;
81 };
82
83 struct sockpass_mapping {
84 struct list_head list;
85 struct pvcalls_fedata *fedata;
86 struct socket *sock;
87 uint64_t id;
88 struct xen_pvcalls_request reqcopy;
89 spinlock_t copy_lock;
90 struct workqueue_struct *wq;
91 struct work_struct register_work;
92 void (*saved_data_ready)(struct sock *sk);
93 };
94
95 static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map);
96 static int pvcalls_back_release_active(struct xenbus_device *dev,
97 struct pvcalls_fedata *fedata,
98 struct sock_mapping *map);
99
pvcalls_conn_back_read(void * opaque)100 static bool pvcalls_conn_back_read(void *opaque)
101 {
102 struct sock_mapping *map = (struct sock_mapping *)opaque;
103 struct msghdr msg;
104 struct kvec vec[2];
105 RING_IDX cons, prod, size, wanted, array_size, masked_prod, masked_cons;
106 int32_t error;
107 struct pvcalls_data_intf *intf = map->ring;
108 struct pvcalls_data *data = &map->data;
109 unsigned long flags;
110 int ret;
111
112 array_size = XEN_FLEX_RING_SIZE(map->ring_order);
113 cons = intf->in_cons;
114 prod = intf->in_prod;
115 error = intf->in_error;
116 /* read the indexes first, then deal with the data */
117 virt_mb();
118
119 if (error)
120 return false;
121
122 size = pvcalls_queued(prod, cons, array_size);
123 if (size >= array_size)
124 return false;
125 spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags);
126 if (skb_queue_empty(&map->sock->sk->sk_receive_queue)) {
127 atomic_set(&map->read, 0);
128 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock,
129 flags);
130 return true;
131 }
132 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags);
133 wanted = array_size - size;
134 masked_prod = pvcalls_mask(prod, array_size);
135 masked_cons = pvcalls_mask(cons, array_size);
136
137 memset(&msg, 0, sizeof(msg));
138 if (masked_prod < masked_cons) {
139 vec[0].iov_base = data->in + masked_prod;
140 vec[0].iov_len = wanted;
141 iov_iter_kvec(&msg.msg_iter, ITER_KVEC|WRITE, vec, 1, wanted);
142 } else {
143 vec[0].iov_base = data->in + masked_prod;
144 vec[0].iov_len = array_size - masked_prod;
145 vec[1].iov_base = data->in;
146 vec[1].iov_len = wanted - vec[0].iov_len;
147 iov_iter_kvec(&msg.msg_iter, ITER_KVEC|WRITE, vec, 2, wanted);
148 }
149
150 atomic_set(&map->read, 0);
151 ret = inet_recvmsg(map->sock, &msg, wanted, MSG_DONTWAIT);
152 WARN_ON(ret > wanted);
153 if (ret == -EAGAIN) /* shouldn't happen */
154 return true;
155 if (!ret)
156 ret = -ENOTCONN;
157 spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags);
158 if (ret > 0 && !skb_queue_empty(&map->sock->sk->sk_receive_queue))
159 atomic_inc(&map->read);
160 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags);
161
162 /* write the data, then modify the indexes */
163 virt_wmb();
164 if (ret < 0) {
165 atomic_set(&map->read, 0);
166 intf->in_error = ret;
167 } else
168 intf->in_prod = prod + ret;
169 /* update the indexes, then notify the other end */
170 virt_wmb();
171 notify_remote_via_irq(map->irq);
172
173 return true;
174 }
175
pvcalls_conn_back_write(struct sock_mapping * map)176 static bool pvcalls_conn_back_write(struct sock_mapping *map)
177 {
178 struct pvcalls_data_intf *intf = map->ring;
179 struct pvcalls_data *data = &map->data;
180 struct msghdr msg;
181 struct kvec vec[2];
182 RING_IDX cons, prod, size, array_size;
183 int ret;
184
185 cons = intf->out_cons;
186 prod = intf->out_prod;
187 /* read the indexes before dealing with the data */
188 virt_mb();
189
190 array_size = XEN_FLEX_RING_SIZE(map->ring_order);
191 size = pvcalls_queued(prod, cons, array_size);
192 if (size == 0)
193 return false;
194
195 memset(&msg, 0, sizeof(msg));
196 msg.msg_flags |= MSG_DONTWAIT;
197 if (pvcalls_mask(prod, array_size) > pvcalls_mask(cons, array_size)) {
198 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
199 vec[0].iov_len = size;
200 iov_iter_kvec(&msg.msg_iter, ITER_KVEC|READ, vec, 1, size);
201 } else {
202 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
203 vec[0].iov_len = array_size - pvcalls_mask(cons, array_size);
204 vec[1].iov_base = data->out;
205 vec[1].iov_len = size - vec[0].iov_len;
206 iov_iter_kvec(&msg.msg_iter, ITER_KVEC|READ, vec, 2, size);
207 }
208
209 atomic_set(&map->write, 0);
210 ret = inet_sendmsg(map->sock, &msg, size);
211 if (ret == -EAGAIN) {
212 atomic_inc(&map->write);
213 atomic_inc(&map->io);
214 return true;
215 }
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 atomic_inc(&map->io);
231 }
232 notify_remote_via_irq(map->irq);
233
234 return true;
235 }
236
pvcalls_back_ioworker(struct work_struct * work)237 static void pvcalls_back_ioworker(struct work_struct *work)
238 {
239 struct pvcalls_ioworker *ioworker = container_of(work,
240 struct pvcalls_ioworker, register_work);
241 struct sock_mapping *map = container_of(ioworker, struct sock_mapping,
242 ioworker);
243 unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
244
245 while (atomic_read(&map->io) > 0) {
246 if (atomic_read(&map->release) > 0) {
247 atomic_set(&map->release, 0);
248 return;
249 }
250
251 if (atomic_read(&map->read) > 0 &&
252 pvcalls_conn_back_read(map))
253 eoi_flags = 0;
254 if (atomic_read(&map->write) > 0 &&
255 pvcalls_conn_back_write(map))
256 eoi_flags = 0;
257
258 if (atomic_read(&map->eoi) > 0 && !atomic_read(&map->write)) {
259 atomic_set(&map->eoi, 0);
260 xen_irq_lateeoi(map->irq, eoi_flags);
261 eoi_flags = XEN_EOI_FLAG_SPURIOUS;
262 }
263
264 atomic_dec(&map->io);
265 }
266 }
267
pvcalls_back_socket(struct xenbus_device * dev,struct xen_pvcalls_request * req)268 static int pvcalls_back_socket(struct xenbus_device *dev,
269 struct xen_pvcalls_request *req)
270 {
271 struct pvcalls_fedata *fedata;
272 int ret;
273 struct xen_pvcalls_response *rsp;
274
275 fedata = dev_get_drvdata(&dev->dev);
276
277 if (req->u.socket.domain != AF_INET ||
278 req->u.socket.type != SOCK_STREAM ||
279 (req->u.socket.protocol != IPPROTO_IP &&
280 req->u.socket.protocol != AF_INET))
281 ret = -EAFNOSUPPORT;
282 else
283 ret = 0;
284
285 /* leave the actual socket allocation for later */
286
287 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
288 rsp->req_id = req->req_id;
289 rsp->cmd = req->cmd;
290 rsp->u.socket.id = req->u.socket.id;
291 rsp->ret = ret;
292
293 return 0;
294 }
295
pvcalls_sk_state_change(struct sock * sock)296 static void pvcalls_sk_state_change(struct sock *sock)
297 {
298 struct sock_mapping *map = sock->sk_user_data;
299
300 if (map == NULL)
301 return;
302
303 atomic_inc(&map->read);
304 notify_remote_via_irq(map->irq);
305 }
306
pvcalls_sk_data_ready(struct sock * sock)307 static void pvcalls_sk_data_ready(struct sock *sock)
308 {
309 struct sock_mapping *map = sock->sk_user_data;
310 struct pvcalls_ioworker *iow;
311
312 if (map == NULL)
313 return;
314
315 iow = &map->ioworker;
316 atomic_inc(&map->read);
317 atomic_inc(&map->io);
318 queue_work(iow->wq, &iow->register_work);
319 }
320
pvcalls_new_active_socket(struct pvcalls_fedata * fedata,uint64_t id,grant_ref_t ref,uint32_t evtchn,struct socket * sock)321 static struct sock_mapping *pvcalls_new_active_socket(
322 struct pvcalls_fedata *fedata,
323 uint64_t id,
324 grant_ref_t ref,
325 uint32_t evtchn,
326 struct socket *sock)
327 {
328 int ret;
329 struct sock_mapping *map;
330 void *page;
331
332 map = kzalloc(sizeof(*map), GFP_KERNEL);
333 if (map == NULL)
334 return NULL;
335
336 map->fedata = fedata;
337 map->sock = sock;
338 map->id = id;
339 map->ref = ref;
340
341 ret = xenbus_map_ring_valloc(fedata->dev, &ref, 1, &page);
342 if (ret < 0)
343 goto out;
344 map->ring = page;
345 map->ring_order = map->ring->ring_order;
346 /* first read the order, then map the data ring */
347 virt_rmb();
348 if (map->ring_order > MAX_RING_ORDER) {
349 pr_warn("%s frontend requested ring_order %u, which is > MAX (%u)\n",
350 __func__, map->ring_order, MAX_RING_ORDER);
351 goto out;
352 }
353 ret = xenbus_map_ring_valloc(fedata->dev, map->ring->ref,
354 (1 << map->ring_order), &page);
355 if (ret < 0)
356 goto out;
357 map->bytes = page;
358
359 ret = bind_interdomain_evtchn_to_irqhandler_lateeoi(
360 fedata->dev->otherend_id, evtchn,
361 pvcalls_back_conn_event, 0, "pvcalls-backend", map);
362 if (ret < 0)
363 goto out;
364 map->irq = ret;
365
366 map->data.in = map->bytes;
367 map->data.out = map->bytes + XEN_FLEX_RING_SIZE(map->ring_order);
368
369 map->ioworker.wq = alloc_workqueue("pvcalls_io", WQ_UNBOUND, 1);
370 if (!map->ioworker.wq)
371 goto out;
372 atomic_set(&map->io, 1);
373 INIT_WORK(&map->ioworker.register_work, pvcalls_back_ioworker);
374
375 down(&fedata->socket_lock);
376 list_add_tail(&map->list, &fedata->socket_mappings);
377 up(&fedata->socket_lock);
378
379 write_lock_bh(&map->sock->sk->sk_callback_lock);
380 map->saved_data_ready = map->sock->sk->sk_data_ready;
381 map->sock->sk->sk_user_data = map;
382 map->sock->sk->sk_data_ready = pvcalls_sk_data_ready;
383 map->sock->sk->sk_state_change = pvcalls_sk_state_change;
384 write_unlock_bh(&map->sock->sk->sk_callback_lock);
385
386 return map;
387 out:
388 down(&fedata->socket_lock);
389 list_del(&map->list);
390 pvcalls_back_release_active(fedata->dev, fedata, map);
391 up(&fedata->socket_lock);
392 return NULL;
393 }
394
pvcalls_back_connect(struct xenbus_device * dev,struct xen_pvcalls_request * req)395 static int pvcalls_back_connect(struct xenbus_device *dev,
396 struct xen_pvcalls_request *req)
397 {
398 struct pvcalls_fedata *fedata;
399 int ret = -EINVAL;
400 struct socket *sock;
401 struct sock_mapping *map;
402 struct xen_pvcalls_response *rsp;
403 struct sockaddr *sa = (struct sockaddr *)&req->u.connect.addr;
404
405 fedata = dev_get_drvdata(&dev->dev);
406
407 if (req->u.connect.len < sizeof(sa->sa_family) ||
408 req->u.connect.len > sizeof(req->u.connect.addr) ||
409 sa->sa_family != AF_INET)
410 goto out;
411
412 ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock);
413 if (ret < 0)
414 goto out;
415 ret = inet_stream_connect(sock, sa, req->u.connect.len, 0);
416 if (ret < 0) {
417 sock_release(sock);
418 goto out;
419 }
420
421 map = pvcalls_new_active_socket(fedata,
422 req->u.connect.id,
423 req->u.connect.ref,
424 req->u.connect.evtchn,
425 sock);
426 if (!map) {
427 ret = -EFAULT;
428 sock_release(sock);
429 }
430
431 out:
432 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
433 rsp->req_id = req->req_id;
434 rsp->cmd = req->cmd;
435 rsp->u.connect.id = req->u.connect.id;
436 rsp->ret = ret;
437
438 return 0;
439 }
440
pvcalls_back_release_active(struct xenbus_device * dev,struct pvcalls_fedata * fedata,struct sock_mapping * map)441 static int pvcalls_back_release_active(struct xenbus_device *dev,
442 struct pvcalls_fedata *fedata,
443 struct sock_mapping *map)
444 {
445 disable_irq(map->irq);
446 if (map->sock->sk != NULL) {
447 write_lock_bh(&map->sock->sk->sk_callback_lock);
448 map->sock->sk->sk_user_data = NULL;
449 map->sock->sk->sk_data_ready = map->saved_data_ready;
450 write_unlock_bh(&map->sock->sk->sk_callback_lock);
451 }
452
453 atomic_set(&map->release, 1);
454 flush_work(&map->ioworker.register_work);
455
456 xenbus_unmap_ring_vfree(dev, map->bytes);
457 xenbus_unmap_ring_vfree(dev, (void *)map->ring);
458 unbind_from_irqhandler(map->irq, map);
459
460 sock_release(map->sock);
461 kfree(map);
462
463 return 0;
464 }
465
pvcalls_back_release_passive(struct xenbus_device * dev,struct pvcalls_fedata * fedata,struct sockpass_mapping * mappass)466 static int pvcalls_back_release_passive(struct xenbus_device *dev,
467 struct pvcalls_fedata *fedata,
468 struct sockpass_mapping *mappass)
469 {
470 if (mappass->sock->sk != NULL) {
471 write_lock_bh(&mappass->sock->sk->sk_callback_lock);
472 mappass->sock->sk->sk_user_data = NULL;
473 mappass->sock->sk->sk_data_ready = mappass->saved_data_ready;
474 write_unlock_bh(&mappass->sock->sk->sk_callback_lock);
475 }
476 sock_release(mappass->sock);
477 flush_workqueue(mappass->wq);
478 destroy_workqueue(mappass->wq);
479 kfree(mappass);
480
481 return 0;
482 }
483
pvcalls_back_release(struct xenbus_device * dev,struct xen_pvcalls_request * req)484 static int pvcalls_back_release(struct xenbus_device *dev,
485 struct xen_pvcalls_request *req)
486 {
487 struct pvcalls_fedata *fedata;
488 struct sock_mapping *map, *n;
489 struct sockpass_mapping *mappass;
490 int ret = 0;
491 struct xen_pvcalls_response *rsp;
492
493 fedata = dev_get_drvdata(&dev->dev);
494
495 down(&fedata->socket_lock);
496 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {
497 if (map->id == req->u.release.id) {
498 list_del(&map->list);
499 up(&fedata->socket_lock);
500 ret = pvcalls_back_release_active(dev, fedata, map);
501 goto out;
502 }
503 }
504 mappass = radix_tree_lookup(&fedata->socketpass_mappings,
505 req->u.release.id);
506 if (mappass != NULL) {
507 radix_tree_delete(&fedata->socketpass_mappings, mappass->id);
508 up(&fedata->socket_lock);
509 ret = pvcalls_back_release_passive(dev, fedata, mappass);
510 } else
511 up(&fedata->socket_lock);
512
513 out:
514 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
515 rsp->req_id = req->req_id;
516 rsp->u.release.id = req->u.release.id;
517 rsp->cmd = req->cmd;
518 rsp->ret = ret;
519 return 0;
520 }
521
__pvcalls_back_accept(struct work_struct * work)522 static void __pvcalls_back_accept(struct work_struct *work)
523 {
524 struct sockpass_mapping *mappass = container_of(
525 work, struct sockpass_mapping, register_work);
526 struct sock_mapping *map;
527 struct pvcalls_ioworker *iow;
528 struct pvcalls_fedata *fedata;
529 struct socket *sock;
530 struct xen_pvcalls_response *rsp;
531 struct xen_pvcalls_request *req;
532 int notify;
533 int ret = -EINVAL;
534 unsigned long flags;
535
536 fedata = mappass->fedata;
537 /*
538 * __pvcalls_back_accept can race against pvcalls_back_accept.
539 * We only need to check the value of "cmd" on read. It could be
540 * done atomically, but to simplify the code on the write side, we
541 * use a spinlock.
542 */
543 spin_lock_irqsave(&mappass->copy_lock, flags);
544 req = &mappass->reqcopy;
545 if (req->cmd != PVCALLS_ACCEPT) {
546 spin_unlock_irqrestore(&mappass->copy_lock, flags);
547 return;
548 }
549 spin_unlock_irqrestore(&mappass->copy_lock, flags);
550
551 sock = sock_alloc();
552 if (sock == NULL)
553 goto out_error;
554 sock->type = mappass->sock->type;
555 sock->ops = mappass->sock->ops;
556
557 ret = inet_accept(mappass->sock, sock, O_NONBLOCK, true);
558 if (ret == -EAGAIN) {
559 sock_release(sock);
560 return;
561 }
562
563 map = pvcalls_new_active_socket(fedata,
564 req->u.accept.id_new,
565 req->u.accept.ref,
566 req->u.accept.evtchn,
567 sock);
568 if (!map) {
569 ret = -EFAULT;
570 sock_release(sock);
571 goto out_error;
572 }
573
574 map->sockpass = mappass;
575 iow = &map->ioworker;
576 atomic_inc(&map->read);
577 atomic_inc(&map->io);
578 queue_work(iow->wq, &iow->register_work);
579
580 out_error:
581 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
582 rsp->req_id = req->req_id;
583 rsp->cmd = req->cmd;
584 rsp->u.accept.id = req->u.accept.id;
585 rsp->ret = ret;
586 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);
587 if (notify)
588 notify_remote_via_irq(fedata->irq);
589
590 mappass->reqcopy.cmd = 0;
591 }
592
pvcalls_pass_sk_data_ready(struct sock * sock)593 static void pvcalls_pass_sk_data_ready(struct sock *sock)
594 {
595 struct sockpass_mapping *mappass = sock->sk_user_data;
596 struct pvcalls_fedata *fedata;
597 struct xen_pvcalls_response *rsp;
598 unsigned long flags;
599 int notify;
600
601 if (mappass == NULL)
602 return;
603
604 fedata = mappass->fedata;
605 spin_lock_irqsave(&mappass->copy_lock, flags);
606 if (mappass->reqcopy.cmd == PVCALLS_POLL) {
607 rsp = RING_GET_RESPONSE(&fedata->ring,
608 fedata->ring.rsp_prod_pvt++);
609 rsp->req_id = mappass->reqcopy.req_id;
610 rsp->u.poll.id = mappass->reqcopy.u.poll.id;
611 rsp->cmd = mappass->reqcopy.cmd;
612 rsp->ret = 0;
613
614 mappass->reqcopy.cmd = 0;
615 spin_unlock_irqrestore(&mappass->copy_lock, flags);
616
617 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);
618 if (notify)
619 notify_remote_via_irq(mappass->fedata->irq);
620 } else {
621 spin_unlock_irqrestore(&mappass->copy_lock, flags);
622 queue_work(mappass->wq, &mappass->register_work);
623 }
624 }
625
pvcalls_back_bind(struct xenbus_device * dev,struct xen_pvcalls_request * req)626 static int pvcalls_back_bind(struct xenbus_device *dev,
627 struct xen_pvcalls_request *req)
628 {
629 struct pvcalls_fedata *fedata;
630 int ret;
631 struct sockpass_mapping *map;
632 struct xen_pvcalls_response *rsp;
633
634 fedata = dev_get_drvdata(&dev->dev);
635
636 map = kzalloc(sizeof(*map), GFP_KERNEL);
637 if (map == NULL) {
638 ret = -ENOMEM;
639 goto out;
640 }
641
642 INIT_WORK(&map->register_work, __pvcalls_back_accept);
643 spin_lock_init(&map->copy_lock);
644 map->wq = alloc_workqueue("pvcalls_wq", WQ_UNBOUND, 1);
645 if (!map->wq) {
646 ret = -ENOMEM;
647 goto out;
648 }
649
650 ret = sock_create(AF_INET, SOCK_STREAM, 0, &map->sock);
651 if (ret < 0)
652 goto out;
653
654 ret = inet_bind(map->sock, (struct sockaddr *)&req->u.bind.addr,
655 req->u.bind.len);
656 if (ret < 0)
657 goto out;
658
659 map->fedata = fedata;
660 map->id = req->u.bind.id;
661
662 down(&fedata->socket_lock);
663 ret = radix_tree_insert(&fedata->socketpass_mappings, map->id,
664 map);
665 up(&fedata->socket_lock);
666 if (ret)
667 goto out;
668
669 write_lock_bh(&map->sock->sk->sk_callback_lock);
670 map->saved_data_ready = map->sock->sk->sk_data_ready;
671 map->sock->sk->sk_user_data = map;
672 map->sock->sk->sk_data_ready = pvcalls_pass_sk_data_ready;
673 write_unlock_bh(&map->sock->sk->sk_callback_lock);
674
675 out:
676 if (ret) {
677 if (map && map->sock)
678 sock_release(map->sock);
679 if (map && map->wq)
680 destroy_workqueue(map->wq);
681 kfree(map);
682 }
683 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
684 rsp->req_id = req->req_id;
685 rsp->cmd = req->cmd;
686 rsp->u.bind.id = req->u.bind.id;
687 rsp->ret = ret;
688 return 0;
689 }
690
pvcalls_back_listen(struct xenbus_device * dev,struct xen_pvcalls_request * req)691 static int pvcalls_back_listen(struct xenbus_device *dev,
692 struct xen_pvcalls_request *req)
693 {
694 struct pvcalls_fedata *fedata;
695 int ret = -EINVAL;
696 struct sockpass_mapping *map;
697 struct xen_pvcalls_response *rsp;
698
699 fedata = dev_get_drvdata(&dev->dev);
700
701 down(&fedata->socket_lock);
702 map = radix_tree_lookup(&fedata->socketpass_mappings, req->u.listen.id);
703 up(&fedata->socket_lock);
704 if (map == NULL)
705 goto out;
706
707 ret = inet_listen(map->sock, req->u.listen.backlog);
708
709 out:
710 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
711 rsp->req_id = req->req_id;
712 rsp->cmd = req->cmd;
713 rsp->u.listen.id = req->u.listen.id;
714 rsp->ret = ret;
715 return 0;
716 }
717
pvcalls_back_accept(struct xenbus_device * dev,struct xen_pvcalls_request * req)718 static int pvcalls_back_accept(struct xenbus_device *dev,
719 struct xen_pvcalls_request *req)
720 {
721 struct pvcalls_fedata *fedata;
722 struct sockpass_mapping *mappass;
723 int ret = -EINVAL;
724 struct xen_pvcalls_response *rsp;
725 unsigned long flags;
726
727 fedata = dev_get_drvdata(&dev->dev);
728
729 down(&fedata->socket_lock);
730 mappass = radix_tree_lookup(&fedata->socketpass_mappings,
731 req->u.accept.id);
732 up(&fedata->socket_lock);
733 if (mappass == NULL)
734 goto out_error;
735
736 /*
737 * Limitation of the current implementation: only support one
738 * concurrent accept or poll call on one socket.
739 */
740 spin_lock_irqsave(&mappass->copy_lock, flags);
741 if (mappass->reqcopy.cmd != 0) {
742 spin_unlock_irqrestore(&mappass->copy_lock, flags);
743 ret = -EINTR;
744 goto out_error;
745 }
746
747 mappass->reqcopy = *req;
748 spin_unlock_irqrestore(&mappass->copy_lock, flags);
749 queue_work(mappass->wq, &mappass->register_work);
750
751 /* Tell the caller we don't need to send back a notification yet */
752 return -1;
753
754 out_error:
755 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
756 rsp->req_id = req->req_id;
757 rsp->cmd = req->cmd;
758 rsp->u.accept.id = req->u.accept.id;
759 rsp->ret = ret;
760 return 0;
761 }
762
pvcalls_back_poll(struct xenbus_device * dev,struct xen_pvcalls_request * req)763 static int pvcalls_back_poll(struct xenbus_device *dev,
764 struct xen_pvcalls_request *req)
765 {
766 struct pvcalls_fedata *fedata;
767 struct sockpass_mapping *mappass;
768 struct xen_pvcalls_response *rsp;
769 struct inet_connection_sock *icsk;
770 struct request_sock_queue *queue;
771 unsigned long flags;
772 int ret;
773 bool data;
774
775 fedata = dev_get_drvdata(&dev->dev);
776
777 down(&fedata->socket_lock);
778 mappass = radix_tree_lookup(&fedata->socketpass_mappings,
779 req->u.poll.id);
780 up(&fedata->socket_lock);
781 if (mappass == NULL)
782 return -EINVAL;
783
784 /*
785 * Limitation of the current implementation: only support one
786 * concurrent accept or poll call on one socket.
787 */
788 spin_lock_irqsave(&mappass->copy_lock, flags);
789 if (mappass->reqcopy.cmd != 0) {
790 ret = -EINTR;
791 goto out;
792 }
793
794 mappass->reqcopy = *req;
795 icsk = inet_csk(mappass->sock->sk);
796 queue = &icsk->icsk_accept_queue;
797 data = READ_ONCE(queue->rskq_accept_head) != NULL;
798 if (data) {
799 mappass->reqcopy.cmd = 0;
800 ret = 0;
801 goto out;
802 }
803 spin_unlock_irqrestore(&mappass->copy_lock, flags);
804
805 /* Tell the caller we don't need to send back a notification yet */
806 return -1;
807
808 out:
809 spin_unlock_irqrestore(&mappass->copy_lock, flags);
810
811 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
812 rsp->req_id = req->req_id;
813 rsp->cmd = req->cmd;
814 rsp->u.poll.id = req->u.poll.id;
815 rsp->ret = ret;
816 return 0;
817 }
818
pvcalls_back_handle_cmd(struct xenbus_device * dev,struct xen_pvcalls_request * req)819 static int pvcalls_back_handle_cmd(struct xenbus_device *dev,
820 struct xen_pvcalls_request *req)
821 {
822 int ret = 0;
823
824 switch (req->cmd) {
825 case PVCALLS_SOCKET:
826 ret = pvcalls_back_socket(dev, req);
827 break;
828 case PVCALLS_CONNECT:
829 ret = pvcalls_back_connect(dev, req);
830 break;
831 case PVCALLS_RELEASE:
832 ret = pvcalls_back_release(dev, req);
833 break;
834 case PVCALLS_BIND:
835 ret = pvcalls_back_bind(dev, req);
836 break;
837 case PVCALLS_LISTEN:
838 ret = pvcalls_back_listen(dev, req);
839 break;
840 case PVCALLS_ACCEPT:
841 ret = pvcalls_back_accept(dev, req);
842 break;
843 case PVCALLS_POLL:
844 ret = pvcalls_back_poll(dev, req);
845 break;
846 default:
847 {
848 struct pvcalls_fedata *fedata;
849 struct xen_pvcalls_response *rsp;
850
851 fedata = dev_get_drvdata(&dev->dev);
852 rsp = RING_GET_RESPONSE(
853 &fedata->ring, fedata->ring.rsp_prod_pvt++);
854 rsp->req_id = req->req_id;
855 rsp->cmd = req->cmd;
856 rsp->ret = -ENOTSUPP;
857 break;
858 }
859 }
860 return ret;
861 }
862
pvcalls_back_work(struct pvcalls_fedata * fedata)863 static void pvcalls_back_work(struct pvcalls_fedata *fedata)
864 {
865 int notify, notify_all = 0, more = 1;
866 struct xen_pvcalls_request req;
867 struct xenbus_device *dev = fedata->dev;
868
869 while (more) {
870 while (RING_HAS_UNCONSUMED_REQUESTS(&fedata->ring)) {
871 RING_COPY_REQUEST(&fedata->ring,
872 fedata->ring.req_cons++,
873 &req);
874
875 if (!pvcalls_back_handle_cmd(dev, &req)) {
876 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(
877 &fedata->ring, notify);
878 notify_all += notify;
879 }
880 }
881
882 if (notify_all) {
883 notify_remote_via_irq(fedata->irq);
884 notify_all = 0;
885 }
886
887 RING_FINAL_CHECK_FOR_REQUESTS(&fedata->ring, more);
888 }
889 }
890
pvcalls_back_event(int irq,void * dev_id)891 static irqreturn_t pvcalls_back_event(int irq, void *dev_id)
892 {
893 struct xenbus_device *dev = dev_id;
894 struct pvcalls_fedata *fedata = NULL;
895 unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
896
897 if (dev) {
898 fedata = dev_get_drvdata(&dev->dev);
899 if (fedata) {
900 pvcalls_back_work(fedata);
901 eoi_flags = 0;
902 }
903 }
904
905 xen_irq_lateeoi(irq, eoi_flags);
906
907 return IRQ_HANDLED;
908 }
909
pvcalls_back_conn_event(int irq,void * sock_map)910 static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map)
911 {
912 struct sock_mapping *map = sock_map;
913 struct pvcalls_ioworker *iow;
914
915 if (map == NULL || map->sock == NULL || map->sock->sk == NULL ||
916 map->sock->sk->sk_user_data != map) {
917 xen_irq_lateeoi(irq, 0);
918 return IRQ_HANDLED;
919 }
920
921 iow = &map->ioworker;
922
923 atomic_inc(&map->write);
924 atomic_inc(&map->eoi);
925 atomic_inc(&map->io);
926 queue_work(iow->wq, &iow->register_work);
927
928 return IRQ_HANDLED;
929 }
930
backend_connect(struct xenbus_device * dev)931 static int backend_connect(struct xenbus_device *dev)
932 {
933 int err, evtchn;
934 grant_ref_t ring_ref;
935 struct pvcalls_fedata *fedata = NULL;
936
937 fedata = kzalloc(sizeof(struct pvcalls_fedata), GFP_KERNEL);
938 if (!fedata)
939 return -ENOMEM;
940
941 fedata->irq = -1;
942 err = xenbus_scanf(XBT_NIL, dev->otherend, "port", "%u",
943 &evtchn);
944 if (err != 1) {
945 err = -EINVAL;
946 xenbus_dev_fatal(dev, err, "reading %s/event-channel",
947 dev->otherend);
948 goto error;
949 }
950
951 err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", "%u", &ring_ref);
952 if (err != 1) {
953 err = -EINVAL;
954 xenbus_dev_fatal(dev, err, "reading %s/ring-ref",
955 dev->otherend);
956 goto error;
957 }
958
959 err = bind_interdomain_evtchn_to_irq_lateeoi(dev->otherend_id, evtchn);
960 if (err < 0)
961 goto error;
962 fedata->irq = err;
963
964 err = request_threaded_irq(fedata->irq, NULL, pvcalls_back_event,
965 IRQF_ONESHOT, "pvcalls-back", dev);
966 if (err < 0)
967 goto error;
968
969 err = xenbus_map_ring_valloc(dev, &ring_ref, 1,
970 (void **)&fedata->sring);
971 if (err < 0)
972 goto error;
973
974 BACK_RING_INIT(&fedata->ring, fedata->sring, XEN_PAGE_SIZE * 1);
975 fedata->dev = dev;
976
977 INIT_LIST_HEAD(&fedata->socket_mappings);
978 INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL);
979 sema_init(&fedata->socket_lock, 1);
980 dev_set_drvdata(&dev->dev, fedata);
981
982 down(&pvcalls_back_global.frontends_lock);
983 list_add_tail(&fedata->list, &pvcalls_back_global.frontends);
984 up(&pvcalls_back_global.frontends_lock);
985
986 return 0;
987
988 error:
989 if (fedata->irq >= 0)
990 unbind_from_irqhandler(fedata->irq, dev);
991 if (fedata->sring != NULL)
992 xenbus_unmap_ring_vfree(dev, fedata->sring);
993 kfree(fedata);
994 return err;
995 }
996
backend_disconnect(struct xenbus_device * dev)997 static int backend_disconnect(struct xenbus_device *dev)
998 {
999 struct pvcalls_fedata *fedata;
1000 struct sock_mapping *map, *n;
1001 struct sockpass_mapping *mappass;
1002 struct radix_tree_iter iter;
1003 void **slot;
1004
1005
1006 fedata = dev_get_drvdata(&dev->dev);
1007
1008 down(&fedata->socket_lock);
1009 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {
1010 list_del(&map->list);
1011 pvcalls_back_release_active(dev, fedata, map);
1012 }
1013
1014 radix_tree_for_each_slot(slot, &fedata->socketpass_mappings, &iter, 0) {
1015 mappass = radix_tree_deref_slot(slot);
1016 if (!mappass)
1017 continue;
1018 if (radix_tree_exception(mappass)) {
1019 if (radix_tree_deref_retry(mappass))
1020 slot = radix_tree_iter_retry(&iter);
1021 } else {
1022 radix_tree_delete(&fedata->socketpass_mappings,
1023 mappass->id);
1024 pvcalls_back_release_passive(dev, fedata, mappass);
1025 }
1026 }
1027 up(&fedata->socket_lock);
1028
1029 unbind_from_irqhandler(fedata->irq, dev);
1030 xenbus_unmap_ring_vfree(dev, fedata->sring);
1031
1032 list_del(&fedata->list);
1033 kfree(fedata);
1034 dev_set_drvdata(&dev->dev, NULL);
1035
1036 return 0;
1037 }
1038
pvcalls_back_probe(struct xenbus_device * dev,const struct xenbus_device_id * id)1039 static int pvcalls_back_probe(struct xenbus_device *dev,
1040 const struct xenbus_device_id *id)
1041 {
1042 int err, abort;
1043 struct xenbus_transaction xbt;
1044
1045 again:
1046 abort = 1;
1047
1048 err = xenbus_transaction_start(&xbt);
1049 if (err) {
1050 pr_warn("%s cannot create xenstore transaction\n", __func__);
1051 return err;
1052 }
1053
1054 err = xenbus_printf(xbt, dev->nodename, "versions", "%s",
1055 PVCALLS_VERSIONS);
1056 if (err) {
1057 pr_warn("%s write out 'versions' failed\n", __func__);
1058 goto abort;
1059 }
1060
1061 err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u",
1062 MAX_RING_ORDER);
1063 if (err) {
1064 pr_warn("%s write out 'max-page-order' failed\n", __func__);
1065 goto abort;
1066 }
1067
1068 err = xenbus_printf(xbt, dev->nodename, "function-calls",
1069 XENBUS_FUNCTIONS_CALLS);
1070 if (err) {
1071 pr_warn("%s write out 'function-calls' failed\n", __func__);
1072 goto abort;
1073 }
1074
1075 abort = 0;
1076 abort:
1077 err = xenbus_transaction_end(xbt, abort);
1078 if (err) {
1079 if (err == -EAGAIN && !abort)
1080 goto again;
1081 pr_warn("%s cannot complete xenstore transaction\n", __func__);
1082 return err;
1083 }
1084
1085 if (abort)
1086 return -EFAULT;
1087
1088 xenbus_switch_state(dev, XenbusStateInitWait);
1089
1090 return 0;
1091 }
1092
set_backend_state(struct xenbus_device * dev,enum xenbus_state state)1093 static void set_backend_state(struct xenbus_device *dev,
1094 enum xenbus_state state)
1095 {
1096 while (dev->state != state) {
1097 switch (dev->state) {
1098 case XenbusStateClosed:
1099 switch (state) {
1100 case XenbusStateInitWait:
1101 case XenbusStateConnected:
1102 xenbus_switch_state(dev, XenbusStateInitWait);
1103 break;
1104 case XenbusStateClosing:
1105 xenbus_switch_state(dev, XenbusStateClosing);
1106 break;
1107 default:
1108 WARN_ON(1);
1109 }
1110 break;
1111 case XenbusStateInitWait:
1112 case XenbusStateInitialised:
1113 switch (state) {
1114 case XenbusStateConnected:
1115 if (backend_connect(dev))
1116 return;
1117 xenbus_switch_state(dev, XenbusStateConnected);
1118 break;
1119 case XenbusStateClosing:
1120 case XenbusStateClosed:
1121 xenbus_switch_state(dev, XenbusStateClosing);
1122 break;
1123 default:
1124 WARN_ON(1);
1125 }
1126 break;
1127 case XenbusStateConnected:
1128 switch (state) {
1129 case XenbusStateInitWait:
1130 case XenbusStateClosing:
1131 case XenbusStateClosed:
1132 down(&pvcalls_back_global.frontends_lock);
1133 backend_disconnect(dev);
1134 up(&pvcalls_back_global.frontends_lock);
1135 xenbus_switch_state(dev, XenbusStateClosing);
1136 break;
1137 default:
1138 WARN_ON(1);
1139 }
1140 break;
1141 case XenbusStateClosing:
1142 switch (state) {
1143 case XenbusStateInitWait:
1144 case XenbusStateConnected:
1145 case XenbusStateClosed:
1146 xenbus_switch_state(dev, XenbusStateClosed);
1147 break;
1148 default:
1149 WARN_ON(1);
1150 }
1151 break;
1152 default:
1153 WARN_ON(1);
1154 }
1155 }
1156 }
1157
pvcalls_back_changed(struct xenbus_device * dev,enum xenbus_state frontend_state)1158 static void pvcalls_back_changed(struct xenbus_device *dev,
1159 enum xenbus_state frontend_state)
1160 {
1161 switch (frontend_state) {
1162 case XenbusStateInitialising:
1163 set_backend_state(dev, XenbusStateInitWait);
1164 break;
1165
1166 case XenbusStateInitialised:
1167 case XenbusStateConnected:
1168 set_backend_state(dev, XenbusStateConnected);
1169 break;
1170
1171 case XenbusStateClosing:
1172 set_backend_state(dev, XenbusStateClosing);
1173 break;
1174
1175 case XenbusStateClosed:
1176 set_backend_state(dev, XenbusStateClosed);
1177 if (xenbus_dev_is_online(dev))
1178 break;
1179 device_unregister(&dev->dev);
1180 break;
1181 case XenbusStateUnknown:
1182 set_backend_state(dev, XenbusStateClosed);
1183 device_unregister(&dev->dev);
1184 break;
1185
1186 default:
1187 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1188 frontend_state);
1189 break;
1190 }
1191 }
1192
pvcalls_back_remove(struct xenbus_device * dev)1193 static int pvcalls_back_remove(struct xenbus_device *dev)
1194 {
1195 return 0;
1196 }
1197
pvcalls_back_uevent(struct xenbus_device * xdev,struct kobj_uevent_env * env)1198 static int pvcalls_back_uevent(struct xenbus_device *xdev,
1199 struct kobj_uevent_env *env)
1200 {
1201 return 0;
1202 }
1203
1204 static const struct xenbus_device_id pvcalls_back_ids[] = {
1205 { "pvcalls" },
1206 { "" }
1207 };
1208
1209 static struct xenbus_driver pvcalls_back_driver = {
1210 .ids = pvcalls_back_ids,
1211 .probe = pvcalls_back_probe,
1212 .remove = pvcalls_back_remove,
1213 .uevent = pvcalls_back_uevent,
1214 .otherend_changed = pvcalls_back_changed,
1215 };
1216
pvcalls_back_init(void)1217 static int __init pvcalls_back_init(void)
1218 {
1219 int ret;
1220
1221 if (!xen_domain())
1222 return -ENODEV;
1223
1224 ret = xenbus_register_backend(&pvcalls_back_driver);
1225 if (ret < 0)
1226 return ret;
1227
1228 sema_init(&pvcalls_back_global.frontends_lock, 1);
1229 INIT_LIST_HEAD(&pvcalls_back_global.frontends);
1230 return 0;
1231 }
1232 module_init(pvcalls_back_init);
1233
pvcalls_back_fin(void)1234 static void __exit pvcalls_back_fin(void)
1235 {
1236 struct pvcalls_fedata *fedata, *nfedata;
1237
1238 down(&pvcalls_back_global.frontends_lock);
1239 list_for_each_entry_safe(fedata, nfedata,
1240 &pvcalls_back_global.frontends, list) {
1241 backend_disconnect(fedata->dev);
1242 }
1243 up(&pvcalls_back_global.frontends_lock);
1244
1245 xenbus_unregister_driver(&pvcalls_back_driver);
1246 }
1247
1248 module_exit(pvcalls_back_fin);
1249
1250 MODULE_DESCRIPTION("Xen PV Calls backend driver");
1251 MODULE_AUTHOR("Stefano Stabellini <sstabellini@kernel.org>");
1252 MODULE_LICENSE("GPL");
1253