1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * (c) 2017 Stefano Stabellini <stefano@aporeto.com>
4 */
5
6 #include <linux/inet.h>
7 #include <linux/kthread.h>
8 #include <linux/list.h>
9 #include <linux/radix-tree.h>
10 #include <linux/module.h>
11 #include <linux/semaphore.h>
12 #include <linux/wait.h>
13 #include <net/sock.h>
14 #include <net/inet_common.h>
15 #include <net/inet_connection_sock.h>
16 #include <net/request_sock.h>
17
18 #include <xen/events.h>
19 #include <xen/grant_table.h>
20 #include <xen/xen.h>
21 #include <xen/xenbus.h>
22 #include <xen/interface/io/pvcalls.h>
23
24 #define PVCALLS_VERSIONS "1"
25 #define MAX_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER
26
27 static struct pvcalls_back_global {
28 struct list_head frontends;
29 struct semaphore frontends_lock;
30 } pvcalls_back_global;
31
32 /*
33 * Per-frontend data structure. It contains pointers to the command
34 * ring, its event channel, a list of active sockets and a tree of
35 * passive sockets.
36 */
37 struct pvcalls_fedata {
38 struct list_head list;
39 struct xenbus_device *dev;
40 struct xen_pvcalls_sring *sring;
41 struct xen_pvcalls_back_ring ring;
42 int irq;
43 struct list_head socket_mappings;
44 struct radix_tree_root socketpass_mappings;
45 struct semaphore socket_lock;
46 };
47
48 struct pvcalls_ioworker {
49 struct work_struct register_work;
50 struct workqueue_struct *wq;
51 };
52
53 struct sock_mapping {
54 struct list_head list;
55 struct pvcalls_fedata *fedata;
56 struct sockpass_mapping *sockpass;
57 struct socket *sock;
58 uint64_t id;
59 grant_ref_t ref;
60 struct pvcalls_data_intf *ring;
61 void *bytes;
62 struct pvcalls_data data;
63 uint32_t ring_order;
64 int irq;
65 atomic_t read;
66 atomic_t write;
67 atomic_t io;
68 atomic_t release;
69 atomic_t eoi;
70 void (*saved_data_ready)(struct sock *sk);
71 struct pvcalls_ioworker ioworker;
72 };
73
74 struct sockpass_mapping {
75 struct list_head list;
76 struct pvcalls_fedata *fedata;
77 struct socket *sock;
78 uint64_t id;
79 struct xen_pvcalls_request reqcopy;
80 spinlock_t copy_lock;
81 struct workqueue_struct *wq;
82 struct work_struct register_work;
83 void (*saved_data_ready)(struct sock *sk);
84 };
85
86 static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map);
87 static int pvcalls_back_release_active(struct xenbus_device *dev,
88 struct pvcalls_fedata *fedata,
89 struct sock_mapping *map);
90
pvcalls_conn_back_read(void * opaque)91 static bool pvcalls_conn_back_read(void *opaque)
92 {
93 struct sock_mapping *map = (struct sock_mapping *)opaque;
94 struct msghdr msg;
95 struct kvec vec[2];
96 RING_IDX cons, prod, size, wanted, array_size, masked_prod, masked_cons;
97 int32_t error;
98 struct pvcalls_data_intf *intf = map->ring;
99 struct pvcalls_data *data = &map->data;
100 unsigned long flags;
101 int ret;
102
103 array_size = XEN_FLEX_RING_SIZE(map->ring_order);
104 cons = intf->in_cons;
105 prod = intf->in_prod;
106 error = intf->in_error;
107 /* read the indexes first, then deal with the data */
108 virt_mb();
109
110 if (error)
111 return false;
112
113 size = pvcalls_queued(prod, cons, array_size);
114 if (size >= array_size)
115 return false;
116 spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags);
117 if (skb_queue_empty(&map->sock->sk->sk_receive_queue)) {
118 atomic_set(&map->read, 0);
119 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock,
120 flags);
121 return true;
122 }
123 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags);
124 wanted = array_size - size;
125 masked_prod = pvcalls_mask(prod, array_size);
126 masked_cons = pvcalls_mask(cons, array_size);
127
128 memset(&msg, 0, sizeof(msg));
129 if (masked_prod < masked_cons) {
130 vec[0].iov_base = data->in + masked_prod;
131 vec[0].iov_len = wanted;
132 iov_iter_kvec(&msg.msg_iter, WRITE, vec, 1, wanted);
133 } else {
134 vec[0].iov_base = data->in + masked_prod;
135 vec[0].iov_len = array_size - masked_prod;
136 vec[1].iov_base = data->in;
137 vec[1].iov_len = wanted - vec[0].iov_len;
138 iov_iter_kvec(&msg.msg_iter, WRITE, vec, 2, wanted);
139 }
140
141 atomic_set(&map->read, 0);
142 ret = inet_recvmsg(map->sock, &msg, wanted, MSG_DONTWAIT);
143 WARN_ON(ret > wanted);
144 if (ret == -EAGAIN) /* shouldn't happen */
145 return true;
146 if (!ret)
147 ret = -ENOTCONN;
148 spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags);
149 if (ret > 0 && !skb_queue_empty(&map->sock->sk->sk_receive_queue))
150 atomic_inc(&map->read);
151 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags);
152
153 /* write the data, then modify the indexes */
154 virt_wmb();
155 if (ret < 0) {
156 atomic_set(&map->read, 0);
157 intf->in_error = ret;
158 } else
159 intf->in_prod = prod + ret;
160 /* update the indexes, then notify the other end */
161 virt_wmb();
162 notify_remote_via_irq(map->irq);
163
164 return true;
165 }
166
pvcalls_conn_back_write(struct sock_mapping * map)167 static bool pvcalls_conn_back_write(struct sock_mapping *map)
168 {
169 struct pvcalls_data_intf *intf = map->ring;
170 struct pvcalls_data *data = &map->data;
171 struct msghdr msg;
172 struct kvec vec[2];
173 RING_IDX cons, prod, size, array_size;
174 int ret;
175
176 cons = intf->out_cons;
177 prod = intf->out_prod;
178 /* read the indexes before dealing with the data */
179 virt_mb();
180
181 array_size = XEN_FLEX_RING_SIZE(map->ring_order);
182 size = pvcalls_queued(prod, cons, array_size);
183 if (size == 0)
184 return false;
185
186 memset(&msg, 0, sizeof(msg));
187 msg.msg_flags |= MSG_DONTWAIT;
188 if (pvcalls_mask(prod, array_size) > pvcalls_mask(cons, array_size)) {
189 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
190 vec[0].iov_len = size;
191 iov_iter_kvec(&msg.msg_iter, READ, vec, 1, size);
192 } else {
193 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
194 vec[0].iov_len = array_size - pvcalls_mask(cons, array_size);
195 vec[1].iov_base = data->out;
196 vec[1].iov_len = size - vec[0].iov_len;
197 iov_iter_kvec(&msg.msg_iter, READ, vec, 2, size);
198 }
199
200 atomic_set(&map->write, 0);
201 ret = inet_sendmsg(map->sock, &msg, size);
202 if (ret == -EAGAIN) {
203 atomic_inc(&map->write);
204 atomic_inc(&map->io);
205 return true;
206 }
207
208 /* write the data, then update the indexes */
209 virt_wmb();
210 if (ret < 0) {
211 intf->out_error = ret;
212 } else {
213 intf->out_error = 0;
214 intf->out_cons = cons + ret;
215 prod = intf->out_prod;
216 }
217 /* update the indexes, then notify the other end */
218 virt_wmb();
219 if (prod != cons + ret) {
220 atomic_inc(&map->write);
221 atomic_inc(&map->io);
222 }
223 notify_remote_via_irq(map->irq);
224
225 return true;
226 }
227
pvcalls_back_ioworker(struct work_struct * work)228 static void pvcalls_back_ioworker(struct work_struct *work)
229 {
230 struct pvcalls_ioworker *ioworker = container_of(work,
231 struct pvcalls_ioworker, register_work);
232 struct sock_mapping *map = container_of(ioworker, struct sock_mapping,
233 ioworker);
234 unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
235
236 while (atomic_read(&map->io) > 0) {
237 if (atomic_read(&map->release) > 0) {
238 atomic_set(&map->release, 0);
239 return;
240 }
241
242 if (atomic_read(&map->read) > 0 &&
243 pvcalls_conn_back_read(map))
244 eoi_flags = 0;
245 if (atomic_read(&map->write) > 0 &&
246 pvcalls_conn_back_write(map))
247 eoi_flags = 0;
248
249 if (atomic_read(&map->eoi) > 0 && !atomic_read(&map->write)) {
250 atomic_set(&map->eoi, 0);
251 xen_irq_lateeoi(map->irq, eoi_flags);
252 eoi_flags = XEN_EOI_FLAG_SPURIOUS;
253 }
254
255 atomic_dec(&map->io);
256 }
257 }
258
pvcalls_back_socket(struct xenbus_device * dev,struct xen_pvcalls_request * req)259 static int pvcalls_back_socket(struct xenbus_device *dev,
260 struct xen_pvcalls_request *req)
261 {
262 struct pvcalls_fedata *fedata;
263 int ret;
264 struct xen_pvcalls_response *rsp;
265
266 fedata = dev_get_drvdata(&dev->dev);
267
268 if (req->u.socket.domain != AF_INET ||
269 req->u.socket.type != SOCK_STREAM ||
270 (req->u.socket.protocol != IPPROTO_IP &&
271 req->u.socket.protocol != AF_INET))
272 ret = -EAFNOSUPPORT;
273 else
274 ret = 0;
275
276 /* leave the actual socket allocation for later */
277
278 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
279 rsp->req_id = req->req_id;
280 rsp->cmd = req->cmd;
281 rsp->u.socket.id = req->u.socket.id;
282 rsp->ret = ret;
283
284 return 0;
285 }
286
pvcalls_sk_state_change(struct sock * sock)287 static void pvcalls_sk_state_change(struct sock *sock)
288 {
289 struct sock_mapping *map = sock->sk_user_data;
290
291 if (map == NULL)
292 return;
293
294 atomic_inc(&map->read);
295 notify_remote_via_irq(map->irq);
296 }
297
pvcalls_sk_data_ready(struct sock * sock)298 static void pvcalls_sk_data_ready(struct sock *sock)
299 {
300 struct sock_mapping *map = sock->sk_user_data;
301 struct pvcalls_ioworker *iow;
302
303 if (map == NULL)
304 return;
305
306 iow = &map->ioworker;
307 atomic_inc(&map->read);
308 atomic_inc(&map->io);
309 queue_work(iow->wq, &iow->register_work);
310 }
311
pvcalls_new_active_socket(struct pvcalls_fedata * fedata,uint64_t id,grant_ref_t ref,evtchn_port_t evtchn,struct socket * sock)312 static struct sock_mapping *pvcalls_new_active_socket(
313 struct pvcalls_fedata *fedata,
314 uint64_t id,
315 grant_ref_t ref,
316 evtchn_port_t evtchn,
317 struct socket *sock)
318 {
319 int ret;
320 struct sock_mapping *map;
321 void *page;
322
323 map = kzalloc(sizeof(*map), GFP_KERNEL);
324 if (map == NULL)
325 return NULL;
326
327 map->fedata = fedata;
328 map->sock = sock;
329 map->id = id;
330 map->ref = ref;
331
332 ret = xenbus_map_ring_valloc(fedata->dev, &ref, 1, &page);
333 if (ret < 0)
334 goto out;
335 map->ring = page;
336 map->ring_order = map->ring->ring_order;
337 /* first read the order, then map the data ring */
338 virt_rmb();
339 if (map->ring_order > MAX_RING_ORDER) {
340 pr_warn("%s frontend requested ring_order %u, which is > MAX (%u)\n",
341 __func__, map->ring_order, MAX_RING_ORDER);
342 goto out;
343 }
344 ret = xenbus_map_ring_valloc(fedata->dev, map->ring->ref,
345 (1 << map->ring_order), &page);
346 if (ret < 0)
347 goto out;
348 map->bytes = page;
349
350 ret = bind_interdomain_evtchn_to_irqhandler_lateeoi(
351 fedata->dev, evtchn,
352 pvcalls_back_conn_event, 0, "pvcalls-backend", map);
353 if (ret < 0)
354 goto out;
355 map->irq = ret;
356
357 map->data.in = map->bytes;
358 map->data.out = map->bytes + XEN_FLEX_RING_SIZE(map->ring_order);
359
360 map->ioworker.wq = alloc_workqueue("pvcalls_io", WQ_UNBOUND, 1);
361 if (!map->ioworker.wq)
362 goto out;
363 atomic_set(&map->io, 1);
364 INIT_WORK(&map->ioworker.register_work, pvcalls_back_ioworker);
365
366 down(&fedata->socket_lock);
367 list_add_tail(&map->list, &fedata->socket_mappings);
368 up(&fedata->socket_lock);
369
370 write_lock_bh(&map->sock->sk->sk_callback_lock);
371 map->saved_data_ready = map->sock->sk->sk_data_ready;
372 map->sock->sk->sk_user_data = map;
373 map->sock->sk->sk_data_ready = pvcalls_sk_data_ready;
374 map->sock->sk->sk_state_change = pvcalls_sk_state_change;
375 write_unlock_bh(&map->sock->sk->sk_callback_lock);
376
377 return map;
378 out:
379 down(&fedata->socket_lock);
380 list_del(&map->list);
381 pvcalls_back_release_active(fedata->dev, fedata, map);
382 up(&fedata->socket_lock);
383 return NULL;
384 }
385
pvcalls_back_connect(struct xenbus_device * dev,struct xen_pvcalls_request * req)386 static int pvcalls_back_connect(struct xenbus_device *dev,
387 struct xen_pvcalls_request *req)
388 {
389 struct pvcalls_fedata *fedata;
390 int ret = -EINVAL;
391 struct socket *sock;
392 struct sock_mapping *map;
393 struct xen_pvcalls_response *rsp;
394 struct sockaddr *sa = (struct sockaddr *)&req->u.connect.addr;
395
396 fedata = dev_get_drvdata(&dev->dev);
397
398 if (req->u.connect.len < sizeof(sa->sa_family) ||
399 req->u.connect.len > sizeof(req->u.connect.addr) ||
400 sa->sa_family != AF_INET)
401 goto out;
402
403 ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock);
404 if (ret < 0)
405 goto out;
406 ret = inet_stream_connect(sock, sa, req->u.connect.len, 0);
407 if (ret < 0) {
408 sock_release(sock);
409 goto out;
410 }
411
412 map = pvcalls_new_active_socket(fedata,
413 req->u.connect.id,
414 req->u.connect.ref,
415 req->u.connect.evtchn,
416 sock);
417 if (!map) {
418 ret = -EFAULT;
419 sock_release(sock);
420 }
421
422 out:
423 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
424 rsp->req_id = req->req_id;
425 rsp->cmd = req->cmd;
426 rsp->u.connect.id = req->u.connect.id;
427 rsp->ret = ret;
428
429 return 0;
430 }
431
pvcalls_back_release_active(struct xenbus_device * dev,struct pvcalls_fedata * fedata,struct sock_mapping * map)432 static int pvcalls_back_release_active(struct xenbus_device *dev,
433 struct pvcalls_fedata *fedata,
434 struct sock_mapping *map)
435 {
436 disable_irq(map->irq);
437 if (map->sock->sk != NULL) {
438 write_lock_bh(&map->sock->sk->sk_callback_lock);
439 map->sock->sk->sk_user_data = NULL;
440 map->sock->sk->sk_data_ready = map->saved_data_ready;
441 write_unlock_bh(&map->sock->sk->sk_callback_lock);
442 }
443
444 atomic_set(&map->release, 1);
445 flush_work(&map->ioworker.register_work);
446
447 xenbus_unmap_ring_vfree(dev, map->bytes);
448 xenbus_unmap_ring_vfree(dev, (void *)map->ring);
449 unbind_from_irqhandler(map->irq, map);
450
451 sock_release(map->sock);
452 kfree(map);
453
454 return 0;
455 }
456
pvcalls_back_release_passive(struct xenbus_device * dev,struct pvcalls_fedata * fedata,struct sockpass_mapping * mappass)457 static int pvcalls_back_release_passive(struct xenbus_device *dev,
458 struct pvcalls_fedata *fedata,
459 struct sockpass_mapping *mappass)
460 {
461 if (mappass->sock->sk != NULL) {
462 write_lock_bh(&mappass->sock->sk->sk_callback_lock);
463 mappass->sock->sk->sk_user_data = NULL;
464 mappass->sock->sk->sk_data_ready = mappass->saved_data_ready;
465 write_unlock_bh(&mappass->sock->sk->sk_callback_lock);
466 }
467 sock_release(mappass->sock);
468 destroy_workqueue(mappass->wq);
469 kfree(mappass);
470
471 return 0;
472 }
473
pvcalls_back_release(struct xenbus_device * dev,struct xen_pvcalls_request * req)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
__pvcalls_back_accept(struct work_struct * work)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
pvcalls_pass_sk_data_ready(struct sock * sock)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
pvcalls_back_bind(struct xenbus_device * dev,struct xen_pvcalls_request * req)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
pvcalls_back_listen(struct xenbus_device * dev,struct xen_pvcalls_request * req)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
pvcalls_back_accept(struct xenbus_device * dev,struct xen_pvcalls_request * req)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
pvcalls_back_poll(struct xenbus_device * dev,struct xen_pvcalls_request * req)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
pvcalls_back_handle_cmd(struct xenbus_device * dev,struct xen_pvcalls_request * req)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
pvcalls_back_work(struct pvcalls_fedata * fedata)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
pvcalls_back_event(int irq,void * dev_id)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 unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
886
887 if (dev) {
888 fedata = dev_get_drvdata(&dev->dev);
889 if (fedata) {
890 pvcalls_back_work(fedata);
891 eoi_flags = 0;
892 }
893 }
894
895 xen_irq_lateeoi(irq, eoi_flags);
896
897 return IRQ_HANDLED;
898 }
899
pvcalls_back_conn_event(int irq,void * sock_map)900 static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map)
901 {
902 struct sock_mapping *map = sock_map;
903 struct pvcalls_ioworker *iow;
904
905 if (map == NULL || map->sock == NULL || map->sock->sk == NULL ||
906 map->sock->sk->sk_user_data != map) {
907 xen_irq_lateeoi(irq, 0);
908 return IRQ_HANDLED;
909 }
910
911 iow = &map->ioworker;
912
913 atomic_inc(&map->write);
914 atomic_inc(&map->eoi);
915 atomic_inc(&map->io);
916 queue_work(iow->wq, &iow->register_work);
917
918 return IRQ_HANDLED;
919 }
920
backend_connect(struct xenbus_device * dev)921 static int backend_connect(struct xenbus_device *dev)
922 {
923 int err;
924 evtchn_port_t evtchn;
925 grant_ref_t ring_ref;
926 struct pvcalls_fedata *fedata = NULL;
927
928 fedata = kzalloc(sizeof(struct pvcalls_fedata), GFP_KERNEL);
929 if (!fedata)
930 return -ENOMEM;
931
932 fedata->irq = -1;
933 err = xenbus_scanf(XBT_NIL, dev->otherend, "port", "%u",
934 &evtchn);
935 if (err != 1) {
936 err = -EINVAL;
937 xenbus_dev_fatal(dev, err, "reading %s/event-channel",
938 dev->otherend);
939 goto error;
940 }
941
942 err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", "%u", &ring_ref);
943 if (err != 1) {
944 err = -EINVAL;
945 xenbus_dev_fatal(dev, err, "reading %s/ring-ref",
946 dev->otherend);
947 goto error;
948 }
949
950 err = bind_interdomain_evtchn_to_irq_lateeoi(dev, evtchn);
951 if (err < 0)
952 goto error;
953 fedata->irq = err;
954
955 err = request_threaded_irq(fedata->irq, NULL, pvcalls_back_event,
956 IRQF_ONESHOT, "pvcalls-back", dev);
957 if (err < 0)
958 goto error;
959
960 err = xenbus_map_ring_valloc(dev, &ring_ref, 1,
961 (void **)&fedata->sring);
962 if (err < 0)
963 goto error;
964
965 BACK_RING_INIT(&fedata->ring, fedata->sring, XEN_PAGE_SIZE * 1);
966 fedata->dev = dev;
967
968 INIT_LIST_HEAD(&fedata->socket_mappings);
969 INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL);
970 sema_init(&fedata->socket_lock, 1);
971 dev_set_drvdata(&dev->dev, fedata);
972
973 down(&pvcalls_back_global.frontends_lock);
974 list_add_tail(&fedata->list, &pvcalls_back_global.frontends);
975 up(&pvcalls_back_global.frontends_lock);
976
977 return 0;
978
979 error:
980 if (fedata->irq >= 0)
981 unbind_from_irqhandler(fedata->irq, dev);
982 if (fedata->sring != NULL)
983 xenbus_unmap_ring_vfree(dev, fedata->sring);
984 kfree(fedata);
985 return err;
986 }
987
backend_disconnect(struct xenbus_device * dev)988 static int backend_disconnect(struct xenbus_device *dev)
989 {
990 struct pvcalls_fedata *fedata;
991 struct sock_mapping *map, *n;
992 struct sockpass_mapping *mappass;
993 struct radix_tree_iter iter;
994 void **slot;
995
996
997 fedata = dev_get_drvdata(&dev->dev);
998
999 down(&fedata->socket_lock);
1000 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {
1001 list_del(&map->list);
1002 pvcalls_back_release_active(dev, fedata, map);
1003 }
1004
1005 radix_tree_for_each_slot(slot, &fedata->socketpass_mappings, &iter, 0) {
1006 mappass = radix_tree_deref_slot(slot);
1007 if (!mappass)
1008 continue;
1009 if (radix_tree_exception(mappass)) {
1010 if (radix_tree_deref_retry(mappass))
1011 slot = radix_tree_iter_retry(&iter);
1012 } else {
1013 radix_tree_delete(&fedata->socketpass_mappings,
1014 mappass->id);
1015 pvcalls_back_release_passive(dev, fedata, mappass);
1016 }
1017 }
1018 up(&fedata->socket_lock);
1019
1020 unbind_from_irqhandler(fedata->irq, dev);
1021 xenbus_unmap_ring_vfree(dev, fedata->sring);
1022
1023 list_del(&fedata->list);
1024 kfree(fedata);
1025 dev_set_drvdata(&dev->dev, NULL);
1026
1027 return 0;
1028 }
1029
pvcalls_back_probe(struct xenbus_device * dev,const struct xenbus_device_id * id)1030 static int pvcalls_back_probe(struct xenbus_device *dev,
1031 const struct xenbus_device_id *id)
1032 {
1033 int err, abort;
1034 struct xenbus_transaction xbt;
1035
1036 again:
1037 abort = 1;
1038
1039 err = xenbus_transaction_start(&xbt);
1040 if (err) {
1041 pr_warn("%s cannot create xenstore transaction\n", __func__);
1042 return err;
1043 }
1044
1045 err = xenbus_printf(xbt, dev->nodename, "versions", "%s",
1046 PVCALLS_VERSIONS);
1047 if (err) {
1048 pr_warn("%s write out 'versions' failed\n", __func__);
1049 goto abort;
1050 }
1051
1052 err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u",
1053 MAX_RING_ORDER);
1054 if (err) {
1055 pr_warn("%s write out 'max-page-order' failed\n", __func__);
1056 goto abort;
1057 }
1058
1059 err = xenbus_printf(xbt, dev->nodename, "function-calls",
1060 XENBUS_FUNCTIONS_CALLS);
1061 if (err) {
1062 pr_warn("%s write out 'function-calls' failed\n", __func__);
1063 goto abort;
1064 }
1065
1066 abort = 0;
1067 abort:
1068 err = xenbus_transaction_end(xbt, abort);
1069 if (err) {
1070 if (err == -EAGAIN && !abort)
1071 goto again;
1072 pr_warn("%s cannot complete xenstore transaction\n", __func__);
1073 return err;
1074 }
1075
1076 if (abort)
1077 return -EFAULT;
1078
1079 xenbus_switch_state(dev, XenbusStateInitWait);
1080
1081 return 0;
1082 }
1083
set_backend_state(struct xenbus_device * dev,enum xenbus_state state)1084 static void set_backend_state(struct xenbus_device *dev,
1085 enum xenbus_state state)
1086 {
1087 while (dev->state != state) {
1088 switch (dev->state) {
1089 case XenbusStateClosed:
1090 switch (state) {
1091 case XenbusStateInitWait:
1092 case XenbusStateConnected:
1093 xenbus_switch_state(dev, XenbusStateInitWait);
1094 break;
1095 case XenbusStateClosing:
1096 xenbus_switch_state(dev, XenbusStateClosing);
1097 break;
1098 default:
1099 WARN_ON(1);
1100 }
1101 break;
1102 case XenbusStateInitWait:
1103 case XenbusStateInitialised:
1104 switch (state) {
1105 case XenbusStateConnected:
1106 if (backend_connect(dev))
1107 return;
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
1241 MODULE_DESCRIPTION("Xen PV Calls backend driver");
1242 MODULE_AUTHOR("Stefano Stabellini <sstabellini@kernel.org>");
1243 MODULE_LICENSE("GPL");
1244
