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