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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 atomic_t eoi;
70 void (*saved_data_ready)(struct sock *sk);
71 struct pvcalls_ioworker ioworker;
72};
73
74struct 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
86static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map);
87static int pvcalls_back_release_active(struct xenbus_device *dev,
88 struct pvcalls_fedata *fedata,
89 struct sock_mapping *map);
90
91static 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, ITER_DEST, 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, ITER_DEST, 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
167static 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, ITER_SOURCE, 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, ITER_SOURCE, 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
228static 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
259static 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
287static 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
298static 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
312static 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;
378out:
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
386static 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
422out:
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
432static 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
457static 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
474static 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
503out:
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
512static 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
570out_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
583static 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
616static 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
665out:
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
681static 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
699out:
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
708static 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
744out_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
753static 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
798out:
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
809static 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
853static 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
881static 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
900static 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
921static 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
988static 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
1030static 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
1036again:
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;
1067abort:
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
1084static 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
1149static 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
1184static void pvcalls_back_remove(struct xenbus_device *dev)
1185{
1186}
1187
1188static int pvcalls_back_uevent(struct xenbus_device *xdev,
1189 struct kobj_uevent_env *env)
1190{
1191 return 0;
1192}
1193
1194static const struct xenbus_device_id pvcalls_back_ids[] = {
1195 { "pvcalls" },
1196 { "" }
1197};
1198
1199static struct xenbus_driver pvcalls_back_driver = {
1200 .ids = pvcalls_back_ids,
1201 .probe = pvcalls_back_probe,
1202 .remove = pvcalls_back_remove,
1203 .uevent = pvcalls_back_uevent,
1204 .otherend_changed = pvcalls_back_changed,
1205};
1206
1207static int __init pvcalls_back_init(void)
1208{
1209 int ret;
1210
1211 if (!xen_domain())
1212 return -ENODEV;
1213
1214 ret = xenbus_register_backend(&pvcalls_back_driver);
1215 if (ret < 0)
1216 return ret;
1217
1218 sema_init(&pvcalls_back_global.frontends_lock, 1);
1219 INIT_LIST_HEAD(&pvcalls_back_global.frontends);
1220 return 0;
1221}
1222module_init(pvcalls_back_init);
1223
1224static void __exit pvcalls_back_fin(void)
1225{
1226 struct pvcalls_fedata *fedata, *nfedata;
1227
1228 down(&pvcalls_back_global.frontends_lock);
1229 list_for_each_entry_safe(fedata, nfedata,
1230 &pvcalls_back_global.frontends, list) {
1231 backend_disconnect(fedata->dev);
1232 }
1233 up(&pvcalls_back_global.frontends_lock);
1234
1235 xenbus_unregister_driver(&pvcalls_back_driver);
1236}
1237
1238module_exit(pvcalls_back_fin);
1239
1240MODULE_DESCRIPTION("Xen PV Calls backend driver");
1241MODULE_AUTHOR("Stefano Stabellini <sstabellini@kernel.org>");
1242MODULE_LICENSE("GPL");
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#include <trace/events/sock.h>
18
19#include <xen/events.h>
20#include <xen/grant_table.h>
21#include <xen/xen.h>
22#include <xen/xenbus.h>
23#include <xen/interface/io/pvcalls.h>
24
25#define PVCALLS_VERSIONS "1"
26#define MAX_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER
27
28static struct pvcalls_back_global {
29 struct list_head frontends;
30 struct semaphore frontends_lock;
31} pvcalls_back_global;
32
33/*
34 * Per-frontend data structure. It contains pointers to the command
35 * ring, its event channel, a list of active sockets and a tree of
36 * passive sockets.
37 */
38struct pvcalls_fedata {
39 struct list_head list;
40 struct xenbus_device *dev;
41 struct xen_pvcalls_sring *sring;
42 struct xen_pvcalls_back_ring ring;
43 int irq;
44 struct list_head socket_mappings;
45 struct radix_tree_root socketpass_mappings;
46 struct semaphore socket_lock;
47};
48
49struct pvcalls_ioworker {
50 struct work_struct register_work;
51 struct workqueue_struct *wq;
52};
53
54struct sock_mapping {
55 struct list_head list;
56 struct pvcalls_fedata *fedata;
57 struct sockpass_mapping *sockpass;
58 struct socket *sock;
59 uint64_t id;
60 grant_ref_t ref;
61 struct pvcalls_data_intf *ring;
62 void *bytes;
63 struct pvcalls_data data;
64 uint32_t ring_order;
65 int irq;
66 atomic_t read;
67 atomic_t write;
68 atomic_t io;
69 atomic_t release;
70 atomic_t eoi;
71 void (*saved_data_ready)(struct sock *sk);
72 struct pvcalls_ioworker ioworker;
73};
74
75struct sockpass_mapping {
76 struct list_head list;
77 struct pvcalls_fedata *fedata;
78 struct socket *sock;
79 uint64_t id;
80 struct xen_pvcalls_request reqcopy;
81 spinlock_t copy_lock;
82 struct workqueue_struct *wq;
83 struct work_struct register_work;
84 void (*saved_data_ready)(struct sock *sk);
85};
86
87static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map);
88static int pvcalls_back_release_active(struct xenbus_device *dev,
89 struct pvcalls_fedata *fedata,
90 struct sock_mapping *map);
91
92static bool pvcalls_conn_back_read(void *opaque)
93{
94 struct sock_mapping *map = (struct sock_mapping *)opaque;
95 struct msghdr msg;
96 struct kvec vec[2];
97 RING_IDX cons, prod, size, wanted, array_size, masked_prod, masked_cons;
98 int32_t error;
99 struct pvcalls_data_intf *intf = map->ring;
100 struct pvcalls_data *data = &map->data;
101 unsigned long flags;
102 int ret;
103
104 array_size = XEN_FLEX_RING_SIZE(map->ring_order);
105 cons = intf->in_cons;
106 prod = intf->in_prod;
107 error = intf->in_error;
108 /* read the indexes first, then deal with the data */
109 virt_mb();
110
111 if (error)
112 return false;
113
114 size = pvcalls_queued(prod, cons, array_size);
115 if (size >= array_size)
116 return false;
117 spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags);
118 if (skb_queue_empty(&map->sock->sk->sk_receive_queue)) {
119 atomic_set(&map->read, 0);
120 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock,
121 flags);
122 return true;
123 }
124 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags);
125 wanted = array_size - size;
126 masked_prod = pvcalls_mask(prod, array_size);
127 masked_cons = pvcalls_mask(cons, array_size);
128
129 memset(&msg, 0, sizeof(msg));
130 if (masked_prod < masked_cons) {
131 vec[0].iov_base = data->in + masked_prod;
132 vec[0].iov_len = wanted;
133 iov_iter_kvec(&msg.msg_iter, ITER_DEST, vec, 1, wanted);
134 } else {
135 vec[0].iov_base = data->in + masked_prod;
136 vec[0].iov_len = array_size - masked_prod;
137 vec[1].iov_base = data->in;
138 vec[1].iov_len = wanted - vec[0].iov_len;
139 iov_iter_kvec(&msg.msg_iter, ITER_DEST, vec, 2, wanted);
140 }
141
142 atomic_set(&map->read, 0);
143 ret = inet_recvmsg(map->sock, &msg, wanted, MSG_DONTWAIT);
144 WARN_ON(ret > wanted);
145 if (ret == -EAGAIN) /* shouldn't happen */
146 return true;
147 if (!ret)
148 ret = -ENOTCONN;
149 spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags);
150 if (ret > 0 && !skb_queue_empty(&map->sock->sk->sk_receive_queue))
151 atomic_inc(&map->read);
152 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags);
153
154 /* write the data, then modify the indexes */
155 virt_wmb();
156 if (ret < 0) {
157 atomic_set(&map->read, 0);
158 intf->in_error = ret;
159 } else
160 intf->in_prod = prod + ret;
161 /* update the indexes, then notify the other end */
162 virt_wmb();
163 notify_remote_via_irq(map->irq);
164
165 return true;
166}
167
168static bool pvcalls_conn_back_write(struct sock_mapping *map)
169{
170 struct pvcalls_data_intf *intf = map->ring;
171 struct pvcalls_data *data = &map->data;
172 struct msghdr msg;
173 struct kvec vec[2];
174 RING_IDX cons, prod, size, array_size;
175 int ret;
176
177 atomic_set(&map->write, 0);
178
179 cons = intf->out_cons;
180 prod = intf->out_prod;
181 /* read the indexes before dealing with the data */
182 virt_mb();
183
184 array_size = XEN_FLEX_RING_SIZE(map->ring_order);
185 size = pvcalls_queued(prod, cons, array_size);
186 if (size == 0)
187 return false;
188
189 memset(&msg, 0, sizeof(msg));
190 msg.msg_flags |= MSG_DONTWAIT;
191 if (pvcalls_mask(prod, array_size) > pvcalls_mask(cons, array_size)) {
192 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
193 vec[0].iov_len = size;
194 iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, vec, 1, size);
195 } else {
196 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
197 vec[0].iov_len = array_size - pvcalls_mask(cons, array_size);
198 vec[1].iov_base = data->out;
199 vec[1].iov_len = size - vec[0].iov_len;
200 iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, vec, 2, size);
201 }
202
203 ret = inet_sendmsg(map->sock, &msg, size);
204 if (ret == -EAGAIN) {
205 atomic_inc(&map->write);
206 atomic_inc(&map->io);
207 return true;
208 }
209
210 /* write the data, then update the indexes */
211 virt_wmb();
212 if (ret < 0) {
213 intf->out_error = ret;
214 } else {
215 intf->out_error = 0;
216 intf->out_cons = cons + ret;
217 prod = intf->out_prod;
218 }
219 /* update the indexes, then notify the other end */
220 virt_wmb();
221 if (prod != cons + ret) {
222 atomic_inc(&map->write);
223 atomic_inc(&map->io);
224 }
225 notify_remote_via_irq(map->irq);
226
227 return true;
228}
229
230static void pvcalls_back_ioworker(struct work_struct *work)
231{
232 struct pvcalls_ioworker *ioworker = container_of(work,
233 struct pvcalls_ioworker, register_work);
234 struct sock_mapping *map = container_of(ioworker, struct sock_mapping,
235 ioworker);
236 unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
237
238 while (atomic_read(&map->io) > 0) {
239 if (atomic_read(&map->release) > 0) {
240 atomic_set(&map->release, 0);
241 return;
242 }
243
244 if (atomic_read(&map->read) > 0 &&
245 pvcalls_conn_back_read(map))
246 eoi_flags = 0;
247 if (atomic_read(&map->write) > 0 &&
248 pvcalls_conn_back_write(map))
249 eoi_flags = 0;
250
251 if (atomic_read(&map->eoi) > 0 && !atomic_read(&map->write)) {
252 atomic_set(&map->eoi, 0);
253 xen_irq_lateeoi(map->irq, eoi_flags);
254 eoi_flags = XEN_EOI_FLAG_SPURIOUS;
255 }
256
257 atomic_dec(&map->io);
258 }
259}
260
261static int pvcalls_back_socket(struct xenbus_device *dev,
262 struct xen_pvcalls_request *req)
263{
264 struct pvcalls_fedata *fedata;
265 int ret;
266 struct xen_pvcalls_response *rsp;
267
268 fedata = dev_get_drvdata(&dev->dev);
269
270 if (req->u.socket.domain != AF_INET ||
271 req->u.socket.type != SOCK_STREAM ||
272 (req->u.socket.protocol != IPPROTO_IP &&
273 req->u.socket.protocol != AF_INET))
274 ret = -EAFNOSUPPORT;
275 else
276 ret = 0;
277
278 /* leave the actual socket allocation for later */
279
280 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
281 rsp->req_id = req->req_id;
282 rsp->cmd = req->cmd;
283 rsp->u.socket.id = req->u.socket.id;
284 rsp->ret = ret;
285
286 return 0;
287}
288
289static void pvcalls_sk_state_change(struct sock *sock)
290{
291 struct sock_mapping *map = sock->sk_user_data;
292
293 if (map == NULL)
294 return;
295
296 atomic_inc(&map->read);
297 notify_remote_via_irq(map->irq);
298}
299
300static void pvcalls_sk_data_ready(struct sock *sock)
301{
302 struct sock_mapping *map = sock->sk_user_data;
303 struct pvcalls_ioworker *iow;
304
305 trace_sk_data_ready(sock);
306
307 if (map == NULL)
308 return;
309
310 iow = &map->ioworker;
311 atomic_inc(&map->read);
312 atomic_inc(&map->io);
313 queue_work(iow->wq, &iow->register_work);
314}
315
316static struct sock_mapping *pvcalls_new_active_socket(
317 struct pvcalls_fedata *fedata,
318 uint64_t id,
319 grant_ref_t ref,
320 evtchn_port_t evtchn,
321 struct socket *sock)
322{
323 int ret;
324 struct sock_mapping *map;
325 void *page;
326
327 map = kzalloc(sizeof(*map), GFP_KERNEL);
328 if (map == NULL) {
329 sock_release(sock);
330 return NULL;
331 }
332
333 map->fedata = fedata;
334 map->sock = sock;
335 map->id = id;
336 map->ref = ref;
337
338 ret = xenbus_map_ring_valloc(fedata->dev, &ref, 1, &page);
339 if (ret < 0)
340 goto out;
341 map->ring = page;
342 map->ring_order = map->ring->ring_order;
343 /* first read the order, then map the data ring */
344 virt_rmb();
345 if (map->ring_order > MAX_RING_ORDER) {
346 pr_warn("%s frontend requested ring_order %u, which is > MAX (%u)\n",
347 __func__, map->ring_order, MAX_RING_ORDER);
348 goto out;
349 }
350 ret = xenbus_map_ring_valloc(fedata->dev, map->ring->ref,
351 (1 << map->ring_order), &page);
352 if (ret < 0)
353 goto out;
354 map->bytes = page;
355
356 ret = bind_interdomain_evtchn_to_irqhandler_lateeoi(
357 fedata->dev, evtchn,
358 pvcalls_back_conn_event, 0, "pvcalls-backend", map);
359 if (ret < 0)
360 goto out;
361 map->irq = ret;
362
363 map->data.in = map->bytes;
364 map->data.out = map->bytes + XEN_FLEX_RING_SIZE(map->ring_order);
365
366 map->ioworker.wq = alloc_ordered_workqueue("pvcalls_io", 0);
367 if (!map->ioworker.wq)
368 goto out;
369 atomic_set(&map->io, 1);
370 INIT_WORK(&map->ioworker.register_work, pvcalls_back_ioworker);
371
372 down(&fedata->socket_lock);
373 list_add_tail(&map->list, &fedata->socket_mappings);
374 up(&fedata->socket_lock);
375
376 write_lock_bh(&map->sock->sk->sk_callback_lock);
377 map->saved_data_ready = map->sock->sk->sk_data_ready;
378 map->sock->sk->sk_user_data = map;
379 map->sock->sk->sk_data_ready = pvcalls_sk_data_ready;
380 map->sock->sk->sk_state_change = pvcalls_sk_state_change;
381 write_unlock_bh(&map->sock->sk->sk_callback_lock);
382
383 return map;
384out:
385 down(&fedata->socket_lock);
386 list_del(&map->list);
387 pvcalls_back_release_active(fedata->dev, fedata, map);
388 up(&fedata->socket_lock);
389 return NULL;
390}
391
392static int pvcalls_back_connect(struct xenbus_device *dev,
393 struct xen_pvcalls_request *req)
394{
395 struct pvcalls_fedata *fedata;
396 int ret = -EINVAL;
397 struct socket *sock;
398 struct sock_mapping *map;
399 struct xen_pvcalls_response *rsp;
400 struct sockaddr *sa = (struct sockaddr *)&req->u.connect.addr;
401
402 fedata = dev_get_drvdata(&dev->dev);
403
404 if (req->u.connect.len < sizeof(sa->sa_family) ||
405 req->u.connect.len > sizeof(req->u.connect.addr) ||
406 sa->sa_family != AF_INET)
407 goto out;
408
409 ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock);
410 if (ret < 0)
411 goto out;
412 ret = inet_stream_connect(sock, sa, req->u.connect.len, 0);
413 if (ret < 0) {
414 sock_release(sock);
415 goto out;
416 }
417
418 map = pvcalls_new_active_socket(fedata,
419 req->u.connect.id,
420 req->u.connect.ref,
421 req->u.connect.evtchn,
422 sock);
423 if (!map)
424 ret = -EFAULT;
425
426out:
427 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
428 rsp->req_id = req->req_id;
429 rsp->cmd = req->cmd;
430 rsp->u.connect.id = req->u.connect.id;
431 rsp->ret = ret;
432
433 return 0;
434}
435
436static int pvcalls_back_release_active(struct xenbus_device *dev,
437 struct pvcalls_fedata *fedata,
438 struct sock_mapping *map)
439{
440 disable_irq(map->irq);
441 if (map->sock->sk != NULL) {
442 write_lock_bh(&map->sock->sk->sk_callback_lock);
443 map->sock->sk->sk_user_data = NULL;
444 map->sock->sk->sk_data_ready = map->saved_data_ready;
445 write_unlock_bh(&map->sock->sk->sk_callback_lock);
446 }
447
448 atomic_set(&map->release, 1);
449 flush_work(&map->ioworker.register_work);
450
451 xenbus_unmap_ring_vfree(dev, map->bytes);
452 xenbus_unmap_ring_vfree(dev, (void *)map->ring);
453 unbind_from_irqhandler(map->irq, map);
454
455 sock_release(map->sock);
456 kfree(map);
457
458 return 0;
459}
460
461static int pvcalls_back_release_passive(struct xenbus_device *dev,
462 struct pvcalls_fedata *fedata,
463 struct sockpass_mapping *mappass)
464{
465 if (mappass->sock->sk != NULL) {
466 write_lock_bh(&mappass->sock->sk->sk_callback_lock);
467 mappass->sock->sk->sk_user_data = NULL;
468 mappass->sock->sk->sk_data_ready = mappass->saved_data_ready;
469 write_unlock_bh(&mappass->sock->sk->sk_callback_lock);
470 }
471 sock_release(mappass->sock);
472 destroy_workqueue(mappass->wq);
473 kfree(mappass);
474
475 return 0;
476}
477
478static int pvcalls_back_release(struct xenbus_device *dev,
479 struct xen_pvcalls_request *req)
480{
481 struct pvcalls_fedata *fedata;
482 struct sock_mapping *map, *n;
483 struct sockpass_mapping *mappass;
484 int ret = 0;
485 struct xen_pvcalls_response *rsp;
486
487 fedata = dev_get_drvdata(&dev->dev);
488
489 down(&fedata->socket_lock);
490 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {
491 if (map->id == req->u.release.id) {
492 list_del(&map->list);
493 up(&fedata->socket_lock);
494 ret = pvcalls_back_release_active(dev, fedata, map);
495 goto out;
496 }
497 }
498 mappass = radix_tree_lookup(&fedata->socketpass_mappings,
499 req->u.release.id);
500 if (mappass != NULL) {
501 radix_tree_delete(&fedata->socketpass_mappings, mappass->id);
502 up(&fedata->socket_lock);
503 ret = pvcalls_back_release_passive(dev, fedata, mappass);
504 } else
505 up(&fedata->socket_lock);
506
507out:
508 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
509 rsp->req_id = req->req_id;
510 rsp->u.release.id = req->u.release.id;
511 rsp->cmd = req->cmd;
512 rsp->ret = ret;
513 return 0;
514}
515
516static void __pvcalls_back_accept(struct work_struct *work)
517{
518 struct sockpass_mapping *mappass = container_of(
519 work, struct sockpass_mapping, register_work);
520 struct sock_mapping *map;
521 struct pvcalls_ioworker *iow;
522 struct pvcalls_fedata *fedata;
523 struct socket *sock;
524 struct xen_pvcalls_response *rsp;
525 struct xen_pvcalls_request *req;
526 int notify;
527 int ret = -EINVAL;
528 unsigned long flags;
529
530 fedata = mappass->fedata;
531 /*
532 * __pvcalls_back_accept can race against pvcalls_back_accept.
533 * We only need to check the value of "cmd" on read. It could be
534 * done atomically, but to simplify the code on the write side, we
535 * use a spinlock.
536 */
537 spin_lock_irqsave(&mappass->copy_lock, flags);
538 req = &mappass->reqcopy;
539 if (req->cmd != PVCALLS_ACCEPT) {
540 spin_unlock_irqrestore(&mappass->copy_lock, flags);
541 return;
542 }
543 spin_unlock_irqrestore(&mappass->copy_lock, flags);
544
545 sock = sock_alloc();
546 if (sock == NULL)
547 goto out_error;
548 sock->type = mappass->sock->type;
549 sock->ops = mappass->sock->ops;
550
551 ret = inet_accept(mappass->sock, sock, O_NONBLOCK, true);
552 if (ret == -EAGAIN) {
553 sock_release(sock);
554 return;
555 }
556
557 map = pvcalls_new_active_socket(fedata,
558 req->u.accept.id_new,
559 req->u.accept.ref,
560 req->u.accept.evtchn,
561 sock);
562 if (!map) {
563 ret = -EFAULT;
564 goto out_error;
565 }
566
567 map->sockpass = mappass;
568 iow = &map->ioworker;
569 atomic_inc(&map->read);
570 atomic_inc(&map->io);
571 queue_work(iow->wq, &iow->register_work);
572
573out_error:
574 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
575 rsp->req_id = req->req_id;
576 rsp->cmd = req->cmd;
577 rsp->u.accept.id = req->u.accept.id;
578 rsp->ret = ret;
579 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);
580 if (notify)
581 notify_remote_via_irq(fedata->irq);
582
583 mappass->reqcopy.cmd = 0;
584}
585
586static void pvcalls_pass_sk_data_ready(struct sock *sock)
587{
588 struct sockpass_mapping *mappass = sock->sk_user_data;
589 struct pvcalls_fedata *fedata;
590 struct xen_pvcalls_response *rsp;
591 unsigned long flags;
592 int notify;
593
594 trace_sk_data_ready(sock);
595
596 if (mappass == NULL)
597 return;
598
599 fedata = mappass->fedata;
600 spin_lock_irqsave(&mappass->copy_lock, flags);
601 if (mappass->reqcopy.cmd == PVCALLS_POLL) {
602 rsp = RING_GET_RESPONSE(&fedata->ring,
603 fedata->ring.rsp_prod_pvt++);
604 rsp->req_id = mappass->reqcopy.req_id;
605 rsp->u.poll.id = mappass->reqcopy.u.poll.id;
606 rsp->cmd = mappass->reqcopy.cmd;
607 rsp->ret = 0;
608
609 mappass->reqcopy.cmd = 0;
610 spin_unlock_irqrestore(&mappass->copy_lock, flags);
611
612 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);
613 if (notify)
614 notify_remote_via_irq(mappass->fedata->irq);
615 } else {
616 spin_unlock_irqrestore(&mappass->copy_lock, flags);
617 queue_work(mappass->wq, &mappass->register_work);
618 }
619}
620
621static int pvcalls_back_bind(struct xenbus_device *dev,
622 struct xen_pvcalls_request *req)
623{
624 struct pvcalls_fedata *fedata;
625 int ret;
626 struct sockpass_mapping *map;
627 struct xen_pvcalls_response *rsp;
628
629 fedata = dev_get_drvdata(&dev->dev);
630
631 map = kzalloc(sizeof(*map), GFP_KERNEL);
632 if (map == NULL) {
633 ret = -ENOMEM;
634 goto out;
635 }
636
637 INIT_WORK(&map->register_work, __pvcalls_back_accept);
638 spin_lock_init(&map->copy_lock);
639 map->wq = alloc_ordered_workqueue("pvcalls_wq", 0);
640 if (!map->wq) {
641 ret = -ENOMEM;
642 goto out;
643 }
644
645 ret = sock_create(AF_INET, SOCK_STREAM, 0, &map->sock);
646 if (ret < 0)
647 goto out;
648
649 ret = inet_bind(map->sock, (struct sockaddr *)&req->u.bind.addr,
650 req->u.bind.len);
651 if (ret < 0)
652 goto out;
653
654 map->fedata = fedata;
655 map->id = req->u.bind.id;
656
657 down(&fedata->socket_lock);
658 ret = radix_tree_insert(&fedata->socketpass_mappings, map->id,
659 map);
660 up(&fedata->socket_lock);
661 if (ret)
662 goto out;
663
664 write_lock_bh(&map->sock->sk->sk_callback_lock);
665 map->saved_data_ready = map->sock->sk->sk_data_ready;
666 map->sock->sk->sk_user_data = map;
667 map->sock->sk->sk_data_ready = pvcalls_pass_sk_data_ready;
668 write_unlock_bh(&map->sock->sk->sk_callback_lock);
669
670out:
671 if (ret) {
672 if (map && map->sock)
673 sock_release(map->sock);
674 if (map && map->wq)
675 destroy_workqueue(map->wq);
676 kfree(map);
677 }
678 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
679 rsp->req_id = req->req_id;
680 rsp->cmd = req->cmd;
681 rsp->u.bind.id = req->u.bind.id;
682 rsp->ret = ret;
683 return 0;
684}
685
686static int pvcalls_back_listen(struct xenbus_device *dev,
687 struct xen_pvcalls_request *req)
688{
689 struct pvcalls_fedata *fedata;
690 int ret = -EINVAL;
691 struct sockpass_mapping *map;
692 struct xen_pvcalls_response *rsp;
693
694 fedata = dev_get_drvdata(&dev->dev);
695
696 down(&fedata->socket_lock);
697 map = radix_tree_lookup(&fedata->socketpass_mappings, req->u.listen.id);
698 up(&fedata->socket_lock);
699 if (map == NULL)
700 goto out;
701
702 ret = inet_listen(map->sock, req->u.listen.backlog);
703
704out:
705 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
706 rsp->req_id = req->req_id;
707 rsp->cmd = req->cmd;
708 rsp->u.listen.id = req->u.listen.id;
709 rsp->ret = ret;
710 return 0;
711}
712
713static int pvcalls_back_accept(struct xenbus_device *dev,
714 struct xen_pvcalls_request *req)
715{
716 struct pvcalls_fedata *fedata;
717 struct sockpass_mapping *mappass;
718 int ret = -EINVAL;
719 struct xen_pvcalls_response *rsp;
720 unsigned long flags;
721
722 fedata = dev_get_drvdata(&dev->dev);
723
724 down(&fedata->socket_lock);
725 mappass = radix_tree_lookup(&fedata->socketpass_mappings,
726 req->u.accept.id);
727 up(&fedata->socket_lock);
728 if (mappass == NULL)
729 goto out_error;
730
731 /*
732 * Limitation of the current implementation: only support one
733 * concurrent accept or poll call on one socket.
734 */
735 spin_lock_irqsave(&mappass->copy_lock, flags);
736 if (mappass->reqcopy.cmd != 0) {
737 spin_unlock_irqrestore(&mappass->copy_lock, flags);
738 ret = -EINTR;
739 goto out_error;
740 }
741
742 mappass->reqcopy = *req;
743 spin_unlock_irqrestore(&mappass->copy_lock, flags);
744 queue_work(mappass->wq, &mappass->register_work);
745
746 /* Tell the caller we don't need to send back a notification yet */
747 return -1;
748
749out_error:
750 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
751 rsp->req_id = req->req_id;
752 rsp->cmd = req->cmd;
753 rsp->u.accept.id = req->u.accept.id;
754 rsp->ret = ret;
755 return 0;
756}
757
758static int pvcalls_back_poll(struct xenbus_device *dev,
759 struct xen_pvcalls_request *req)
760{
761 struct pvcalls_fedata *fedata;
762 struct sockpass_mapping *mappass;
763 struct xen_pvcalls_response *rsp;
764 struct inet_connection_sock *icsk;
765 struct request_sock_queue *queue;
766 unsigned long flags;
767 int ret;
768 bool data;
769
770 fedata = dev_get_drvdata(&dev->dev);
771
772 down(&fedata->socket_lock);
773 mappass = radix_tree_lookup(&fedata->socketpass_mappings,
774 req->u.poll.id);
775 up(&fedata->socket_lock);
776 if (mappass == NULL)
777 return -EINVAL;
778
779 /*
780 * Limitation of the current implementation: only support one
781 * concurrent accept or poll call on one socket.
782 */
783 spin_lock_irqsave(&mappass->copy_lock, flags);
784 if (mappass->reqcopy.cmd != 0) {
785 ret = -EINTR;
786 goto out;
787 }
788
789 mappass->reqcopy = *req;
790 icsk = inet_csk(mappass->sock->sk);
791 queue = &icsk->icsk_accept_queue;
792 data = READ_ONCE(queue->rskq_accept_head) != NULL;
793 if (data) {
794 mappass->reqcopy.cmd = 0;
795 ret = 0;
796 goto out;
797 }
798 spin_unlock_irqrestore(&mappass->copy_lock, flags);
799
800 /* Tell the caller we don't need to send back a notification yet */
801 return -1;
802
803out:
804 spin_unlock_irqrestore(&mappass->copy_lock, flags);
805
806 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
807 rsp->req_id = req->req_id;
808 rsp->cmd = req->cmd;
809 rsp->u.poll.id = req->u.poll.id;
810 rsp->ret = ret;
811 return 0;
812}
813
814static int pvcalls_back_handle_cmd(struct xenbus_device *dev,
815 struct xen_pvcalls_request *req)
816{
817 int ret = 0;
818
819 switch (req->cmd) {
820 case PVCALLS_SOCKET:
821 ret = pvcalls_back_socket(dev, req);
822 break;
823 case PVCALLS_CONNECT:
824 ret = pvcalls_back_connect(dev, req);
825 break;
826 case PVCALLS_RELEASE:
827 ret = pvcalls_back_release(dev, req);
828 break;
829 case PVCALLS_BIND:
830 ret = pvcalls_back_bind(dev, req);
831 break;
832 case PVCALLS_LISTEN:
833 ret = pvcalls_back_listen(dev, req);
834 break;
835 case PVCALLS_ACCEPT:
836 ret = pvcalls_back_accept(dev, req);
837 break;
838 case PVCALLS_POLL:
839 ret = pvcalls_back_poll(dev, req);
840 break;
841 default:
842 {
843 struct pvcalls_fedata *fedata;
844 struct xen_pvcalls_response *rsp;
845
846 fedata = dev_get_drvdata(&dev->dev);
847 rsp = RING_GET_RESPONSE(
848 &fedata->ring, fedata->ring.rsp_prod_pvt++);
849 rsp->req_id = req->req_id;
850 rsp->cmd = req->cmd;
851 rsp->ret = -ENOTSUPP;
852 break;
853 }
854 }
855 return ret;
856}
857
858static void pvcalls_back_work(struct pvcalls_fedata *fedata)
859{
860 int notify, notify_all = 0, more = 1;
861 struct xen_pvcalls_request req;
862 struct xenbus_device *dev = fedata->dev;
863
864 while (more) {
865 while (RING_HAS_UNCONSUMED_REQUESTS(&fedata->ring)) {
866 RING_COPY_REQUEST(&fedata->ring,
867 fedata->ring.req_cons++,
868 &req);
869
870 if (!pvcalls_back_handle_cmd(dev, &req)) {
871 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(
872 &fedata->ring, notify);
873 notify_all += notify;
874 }
875 }
876
877 if (notify_all) {
878 notify_remote_via_irq(fedata->irq);
879 notify_all = 0;
880 }
881
882 RING_FINAL_CHECK_FOR_REQUESTS(&fedata->ring, more);
883 }
884}
885
886static irqreturn_t pvcalls_back_event(int irq, void *dev_id)
887{
888 struct xenbus_device *dev = dev_id;
889 struct pvcalls_fedata *fedata = NULL;
890 unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
891
892 if (dev) {
893 fedata = dev_get_drvdata(&dev->dev);
894 if (fedata) {
895 pvcalls_back_work(fedata);
896 eoi_flags = 0;
897 }
898 }
899
900 xen_irq_lateeoi(irq, eoi_flags);
901
902 return IRQ_HANDLED;
903}
904
905static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map)
906{
907 struct sock_mapping *map = sock_map;
908 struct pvcalls_ioworker *iow;
909
910 if (map == NULL || map->sock == NULL || map->sock->sk == NULL ||
911 map->sock->sk->sk_user_data != map) {
912 xen_irq_lateeoi(irq, 0);
913 return IRQ_HANDLED;
914 }
915
916 iow = &map->ioworker;
917
918 atomic_inc(&map->write);
919 atomic_inc(&map->eoi);
920 atomic_inc(&map->io);
921 queue_work(iow->wq, &iow->register_work);
922
923 return IRQ_HANDLED;
924}
925
926static int backend_connect(struct xenbus_device *dev)
927{
928 int err;
929 evtchn_port_t evtchn;
930 grant_ref_t ring_ref;
931 struct pvcalls_fedata *fedata = NULL;
932
933 fedata = kzalloc(sizeof(struct pvcalls_fedata), GFP_KERNEL);
934 if (!fedata)
935 return -ENOMEM;
936
937 fedata->irq = -1;
938 err = xenbus_scanf(XBT_NIL, dev->otherend, "port", "%u",
939 &evtchn);
940 if (err != 1) {
941 err = -EINVAL;
942 xenbus_dev_fatal(dev, err, "reading %s/event-channel",
943 dev->otherend);
944 goto error;
945 }
946
947 err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", "%u", &ring_ref);
948 if (err != 1) {
949 err = -EINVAL;
950 xenbus_dev_fatal(dev, err, "reading %s/ring-ref",
951 dev->otherend);
952 goto error;
953 }
954
955 err = bind_interdomain_evtchn_to_irq_lateeoi(dev, evtchn);
956 if (err < 0)
957 goto error;
958 fedata->irq = err;
959
960 err = request_threaded_irq(fedata->irq, NULL, pvcalls_back_event,
961 IRQF_ONESHOT, "pvcalls-back", dev);
962 if (err < 0)
963 goto error;
964
965 err = xenbus_map_ring_valloc(dev, &ring_ref, 1,
966 (void **)&fedata->sring);
967 if (err < 0)
968 goto error;
969
970 BACK_RING_INIT(&fedata->ring, fedata->sring, XEN_PAGE_SIZE * 1);
971 fedata->dev = dev;
972
973 INIT_LIST_HEAD(&fedata->socket_mappings);
974 INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL);
975 sema_init(&fedata->socket_lock, 1);
976 dev_set_drvdata(&dev->dev, fedata);
977
978 down(&pvcalls_back_global.frontends_lock);
979 list_add_tail(&fedata->list, &pvcalls_back_global.frontends);
980 up(&pvcalls_back_global.frontends_lock);
981
982 return 0;
983
984 error:
985 if (fedata->irq >= 0)
986 unbind_from_irqhandler(fedata->irq, dev);
987 if (fedata->sring != NULL)
988 xenbus_unmap_ring_vfree(dev, fedata->sring);
989 kfree(fedata);
990 return err;
991}
992
993static int backend_disconnect(struct xenbus_device *dev)
994{
995 struct pvcalls_fedata *fedata;
996 struct sock_mapping *map, *n;
997 struct sockpass_mapping *mappass;
998 struct radix_tree_iter iter;
999 void **slot;
1000
1001
1002 fedata = dev_get_drvdata(&dev->dev);
1003
1004 down(&fedata->socket_lock);
1005 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {
1006 list_del(&map->list);
1007 pvcalls_back_release_active(dev, fedata, map);
1008 }
1009
1010 radix_tree_for_each_slot(slot, &fedata->socketpass_mappings, &iter, 0) {
1011 mappass = radix_tree_deref_slot(slot);
1012 if (!mappass)
1013 continue;
1014 if (radix_tree_exception(mappass)) {
1015 if (radix_tree_deref_retry(mappass))
1016 slot = radix_tree_iter_retry(&iter);
1017 } else {
1018 radix_tree_delete(&fedata->socketpass_mappings,
1019 mappass->id);
1020 pvcalls_back_release_passive(dev, fedata, mappass);
1021 }
1022 }
1023 up(&fedata->socket_lock);
1024
1025 unbind_from_irqhandler(fedata->irq, dev);
1026 xenbus_unmap_ring_vfree(dev, fedata->sring);
1027
1028 list_del(&fedata->list);
1029 kfree(fedata);
1030 dev_set_drvdata(&dev->dev, NULL);
1031
1032 return 0;
1033}
1034
1035static int pvcalls_back_probe(struct xenbus_device *dev,
1036 const struct xenbus_device_id *id)
1037{
1038 int err, abort;
1039 struct xenbus_transaction xbt;
1040
1041again:
1042 abort = 1;
1043
1044 err = xenbus_transaction_start(&xbt);
1045 if (err) {
1046 pr_warn("%s cannot create xenstore transaction\n", __func__);
1047 return err;
1048 }
1049
1050 err = xenbus_printf(xbt, dev->nodename, "versions", "%s",
1051 PVCALLS_VERSIONS);
1052 if (err) {
1053 pr_warn("%s write out 'versions' failed\n", __func__);
1054 goto abort;
1055 }
1056
1057 err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u",
1058 MAX_RING_ORDER);
1059 if (err) {
1060 pr_warn("%s write out 'max-page-order' failed\n", __func__);
1061 goto abort;
1062 }
1063
1064 err = xenbus_printf(xbt, dev->nodename, "function-calls",
1065 XENBUS_FUNCTIONS_CALLS);
1066 if (err) {
1067 pr_warn("%s write out 'function-calls' failed\n", __func__);
1068 goto abort;
1069 }
1070
1071 abort = 0;
1072abort:
1073 err = xenbus_transaction_end(xbt, abort);
1074 if (err) {
1075 if (err == -EAGAIN && !abort)
1076 goto again;
1077 pr_warn("%s cannot complete xenstore transaction\n", __func__);
1078 return err;
1079 }
1080
1081 if (abort)
1082 return -EFAULT;
1083
1084 xenbus_switch_state(dev, XenbusStateInitWait);
1085
1086 return 0;
1087}
1088
1089static void set_backend_state(struct xenbus_device *dev,
1090 enum xenbus_state state)
1091{
1092 while (dev->state != state) {
1093 switch (dev->state) {
1094 case XenbusStateClosed:
1095 switch (state) {
1096 case XenbusStateInitWait:
1097 case XenbusStateConnected:
1098 xenbus_switch_state(dev, XenbusStateInitWait);
1099 break;
1100 case XenbusStateClosing:
1101 xenbus_switch_state(dev, XenbusStateClosing);
1102 break;
1103 default:
1104 WARN_ON(1);
1105 }
1106 break;
1107 case XenbusStateInitWait:
1108 case XenbusStateInitialised:
1109 switch (state) {
1110 case XenbusStateConnected:
1111 if (backend_connect(dev))
1112 return;
1113 xenbus_switch_state(dev, XenbusStateConnected);
1114 break;
1115 case XenbusStateClosing:
1116 case XenbusStateClosed:
1117 xenbus_switch_state(dev, XenbusStateClosing);
1118 break;
1119 default:
1120 WARN_ON(1);
1121 }
1122 break;
1123 case XenbusStateConnected:
1124 switch (state) {
1125 case XenbusStateInitWait:
1126 case XenbusStateClosing:
1127 case XenbusStateClosed:
1128 down(&pvcalls_back_global.frontends_lock);
1129 backend_disconnect(dev);
1130 up(&pvcalls_back_global.frontends_lock);
1131 xenbus_switch_state(dev, XenbusStateClosing);
1132 break;
1133 default:
1134 WARN_ON(1);
1135 }
1136 break;
1137 case XenbusStateClosing:
1138 switch (state) {
1139 case XenbusStateInitWait:
1140 case XenbusStateConnected:
1141 case XenbusStateClosed:
1142 xenbus_switch_state(dev, XenbusStateClosed);
1143 break;
1144 default:
1145 WARN_ON(1);
1146 }
1147 break;
1148 default:
1149 WARN_ON(1);
1150 }
1151 }
1152}
1153
1154static void pvcalls_back_changed(struct xenbus_device *dev,
1155 enum xenbus_state frontend_state)
1156{
1157 switch (frontend_state) {
1158 case XenbusStateInitialising:
1159 set_backend_state(dev, XenbusStateInitWait);
1160 break;
1161
1162 case XenbusStateInitialised:
1163 case XenbusStateConnected:
1164 set_backend_state(dev, XenbusStateConnected);
1165 break;
1166
1167 case XenbusStateClosing:
1168 set_backend_state(dev, XenbusStateClosing);
1169 break;
1170
1171 case XenbusStateClosed:
1172 set_backend_state(dev, XenbusStateClosed);
1173 if (xenbus_dev_is_online(dev))
1174 break;
1175 device_unregister(&dev->dev);
1176 break;
1177 case XenbusStateUnknown:
1178 set_backend_state(dev, XenbusStateClosed);
1179 device_unregister(&dev->dev);
1180 break;
1181
1182 default:
1183 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1184 frontend_state);
1185 break;
1186 }
1187}
1188
1189static void pvcalls_back_remove(struct xenbus_device *dev)
1190{
1191}
1192
1193static int pvcalls_back_uevent(const struct xenbus_device *xdev,
1194 struct kobj_uevent_env *env)
1195{
1196 return 0;
1197}
1198
1199static const struct xenbus_device_id pvcalls_back_ids[] = {
1200 { "pvcalls" },
1201 { "" }
1202};
1203
1204static struct xenbus_driver pvcalls_back_driver = {
1205 .ids = pvcalls_back_ids,
1206 .probe = pvcalls_back_probe,
1207 .remove = pvcalls_back_remove,
1208 .uevent = pvcalls_back_uevent,
1209 .otherend_changed = pvcalls_back_changed,
1210};
1211
1212static int __init pvcalls_back_init(void)
1213{
1214 int ret;
1215
1216 if (!xen_domain())
1217 return -ENODEV;
1218
1219 ret = xenbus_register_backend(&pvcalls_back_driver);
1220 if (ret < 0)
1221 return ret;
1222
1223 sema_init(&pvcalls_back_global.frontends_lock, 1);
1224 INIT_LIST_HEAD(&pvcalls_back_global.frontends);
1225 return 0;
1226}
1227module_init(pvcalls_back_init);
1228
1229static void __exit pvcalls_back_fin(void)
1230{
1231 struct pvcalls_fedata *fedata, *nfedata;
1232
1233 down(&pvcalls_back_global.frontends_lock);
1234 list_for_each_entry_safe(fedata, nfedata,
1235 &pvcalls_back_global.frontends, list) {
1236 backend_disconnect(fedata->dev);
1237 }
1238 up(&pvcalls_back_global.frontends_lock);
1239
1240 xenbus_unregister_driver(&pvcalls_back_driver);
1241}
1242
1243module_exit(pvcalls_back_fin);
1244
1245MODULE_DESCRIPTION("Xen PV Calls backend driver");
1246MODULE_AUTHOR("Stefano Stabellini <sstabellini@kernel.org>");
1247MODULE_LICENSE("GPL");