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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#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 proto_accept_arg arg = {
521 .flags = O_NONBLOCK,
522 .kern = true,
523 };
524 struct sock_mapping *map;
525 struct pvcalls_ioworker *iow;
526 struct pvcalls_fedata *fedata;
527 struct socket *sock;
528 struct xen_pvcalls_response *rsp;
529 struct xen_pvcalls_request *req;
530 int notify;
531 int ret = -EINVAL;
532 unsigned long flags;
533
534 fedata = mappass->fedata;
535 /*
536 * __pvcalls_back_accept can race against pvcalls_back_accept.
537 * We only need to check the value of "cmd" on read. It could be
538 * done atomically, but to simplify the code on the write side, we
539 * use a spinlock.
540 */
541 spin_lock_irqsave(&mappass->copy_lock, flags);
542 req = &mappass->reqcopy;
543 if (req->cmd != PVCALLS_ACCEPT) {
544 spin_unlock_irqrestore(&mappass->copy_lock, flags);
545 return;
546 }
547 spin_unlock_irqrestore(&mappass->copy_lock, flags);
548
549 sock = sock_alloc();
550 if (sock == NULL)
551 goto out_error;
552 sock->type = mappass->sock->type;
553 sock->ops = mappass->sock->ops;
554
555 ret = inet_accept(mappass->sock, sock, &arg);
556 if (ret == -EAGAIN) {
557 sock_release(sock);
558 return;
559 }
560
561 map = pvcalls_new_active_socket(fedata,
562 req->u.accept.id_new,
563 req->u.accept.ref,
564 req->u.accept.evtchn,
565 sock);
566 if (!map) {
567 ret = -EFAULT;
568 goto out_error;
569 }
570
571 map->sockpass = mappass;
572 iow = &map->ioworker;
573 atomic_inc(&map->read);
574 atomic_inc(&map->io);
575 queue_work(iow->wq, &iow->register_work);
576
577out_error:
578 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
579 rsp->req_id = req->req_id;
580 rsp->cmd = req->cmd;
581 rsp->u.accept.id = req->u.accept.id;
582 rsp->ret = ret;
583 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);
584 if (notify)
585 notify_remote_via_irq(fedata->irq);
586
587 mappass->reqcopy.cmd = 0;
588}
589
590static void pvcalls_pass_sk_data_ready(struct sock *sock)
591{
592 struct sockpass_mapping *mappass = sock->sk_user_data;
593 struct pvcalls_fedata *fedata;
594 struct xen_pvcalls_response *rsp;
595 unsigned long flags;
596 int notify;
597
598 trace_sk_data_ready(sock);
599
600 if (mappass == NULL)
601 return;
602
603 fedata = mappass->fedata;
604 spin_lock_irqsave(&mappass->copy_lock, flags);
605 if (mappass->reqcopy.cmd == PVCALLS_POLL) {
606 rsp = RING_GET_RESPONSE(&fedata->ring,
607 fedata->ring.rsp_prod_pvt++);
608 rsp->req_id = mappass->reqcopy.req_id;
609 rsp->u.poll.id = mappass->reqcopy.u.poll.id;
610 rsp->cmd = mappass->reqcopy.cmd;
611 rsp->ret = 0;
612
613 mappass->reqcopy.cmd = 0;
614 spin_unlock_irqrestore(&mappass->copy_lock, flags);
615
616 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);
617 if (notify)
618 notify_remote_via_irq(mappass->fedata->irq);
619 } else {
620 spin_unlock_irqrestore(&mappass->copy_lock, flags);
621 queue_work(mappass->wq, &mappass->register_work);
622 }
623}
624
625static int pvcalls_back_bind(struct xenbus_device *dev,
626 struct xen_pvcalls_request *req)
627{
628 struct pvcalls_fedata *fedata;
629 int ret;
630 struct sockpass_mapping *map;
631 struct xen_pvcalls_response *rsp;
632
633 fedata = dev_get_drvdata(&dev->dev);
634
635 map = kzalloc(sizeof(*map), GFP_KERNEL);
636 if (map == NULL) {
637 ret = -ENOMEM;
638 goto out;
639 }
640
641 INIT_WORK(&map->register_work, __pvcalls_back_accept);
642 spin_lock_init(&map->copy_lock);
643 map->wq = alloc_ordered_workqueue("pvcalls_wq", 0);
644 if (!map->wq) {
645 ret = -ENOMEM;
646 goto out;
647 }
648
649 ret = sock_create(AF_INET, SOCK_STREAM, 0, &map->sock);
650 if (ret < 0)
651 goto out;
652
653 ret = inet_bind(map->sock, (struct sockaddr *)&req->u.bind.addr,
654 req->u.bind.len);
655 if (ret < 0)
656 goto out;
657
658 map->fedata = fedata;
659 map->id = req->u.bind.id;
660
661 down(&fedata->socket_lock);
662 ret = radix_tree_insert(&fedata->socketpass_mappings, map->id,
663 map);
664 up(&fedata->socket_lock);
665 if (ret)
666 goto out;
667
668 write_lock_bh(&map->sock->sk->sk_callback_lock);
669 map->saved_data_ready = map->sock->sk->sk_data_ready;
670 map->sock->sk->sk_user_data = map;
671 map->sock->sk->sk_data_ready = pvcalls_pass_sk_data_ready;
672 write_unlock_bh(&map->sock->sk->sk_callback_lock);
673
674out:
675 if (ret) {
676 if (map && map->sock)
677 sock_release(map->sock);
678 if (map && map->wq)
679 destroy_workqueue(map->wq);
680 kfree(map);
681 }
682 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
683 rsp->req_id = req->req_id;
684 rsp->cmd = req->cmd;
685 rsp->u.bind.id = req->u.bind.id;
686 rsp->ret = ret;
687 return 0;
688}
689
690static int pvcalls_back_listen(struct xenbus_device *dev,
691 struct xen_pvcalls_request *req)
692{
693 struct pvcalls_fedata *fedata;
694 int ret = -EINVAL;
695 struct sockpass_mapping *map;
696 struct xen_pvcalls_response *rsp;
697
698 fedata = dev_get_drvdata(&dev->dev);
699
700 down(&fedata->socket_lock);
701 map = radix_tree_lookup(&fedata->socketpass_mappings, req->u.listen.id);
702 up(&fedata->socket_lock);
703 if (map == NULL)
704 goto out;
705
706 ret = inet_listen(map->sock, req->u.listen.backlog);
707
708out:
709 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
710 rsp->req_id = req->req_id;
711 rsp->cmd = req->cmd;
712 rsp->u.listen.id = req->u.listen.id;
713 rsp->ret = ret;
714 return 0;
715}
716
717static int pvcalls_back_accept(struct xenbus_device *dev,
718 struct xen_pvcalls_request *req)
719{
720 struct pvcalls_fedata *fedata;
721 struct sockpass_mapping *mappass;
722 int ret = -EINVAL;
723 struct xen_pvcalls_response *rsp;
724 unsigned long flags;
725
726 fedata = dev_get_drvdata(&dev->dev);
727
728 down(&fedata->socket_lock);
729 mappass = radix_tree_lookup(&fedata->socketpass_mappings,
730 req->u.accept.id);
731 up(&fedata->socket_lock);
732 if (mappass == NULL)
733 goto out_error;
734
735 /*
736 * Limitation of the current implementation: only support one
737 * concurrent accept or poll call on one socket.
738 */
739 spin_lock_irqsave(&mappass->copy_lock, flags);
740 if (mappass->reqcopy.cmd != 0) {
741 spin_unlock_irqrestore(&mappass->copy_lock, flags);
742 ret = -EINTR;
743 goto out_error;
744 }
745
746 mappass->reqcopy = *req;
747 spin_unlock_irqrestore(&mappass->copy_lock, flags);
748 queue_work(mappass->wq, &mappass->register_work);
749
750 /* Tell the caller we don't need to send back a notification yet */
751 return -1;
752
753out_error:
754 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
755 rsp->req_id = req->req_id;
756 rsp->cmd = req->cmd;
757 rsp->u.accept.id = req->u.accept.id;
758 rsp->ret = ret;
759 return 0;
760}
761
762static int pvcalls_back_poll(struct xenbus_device *dev,
763 struct xen_pvcalls_request *req)
764{
765 struct pvcalls_fedata *fedata;
766 struct sockpass_mapping *mappass;
767 struct xen_pvcalls_response *rsp;
768 struct inet_connection_sock *icsk;
769 struct request_sock_queue *queue;
770 unsigned long flags;
771 int ret;
772 bool data;
773
774 fedata = dev_get_drvdata(&dev->dev);
775
776 down(&fedata->socket_lock);
777 mappass = radix_tree_lookup(&fedata->socketpass_mappings,
778 req->u.poll.id);
779 up(&fedata->socket_lock);
780 if (mappass == NULL)
781 return -EINVAL;
782
783 /*
784 * Limitation of the current implementation: only support one
785 * concurrent accept or poll call on one socket.
786 */
787 spin_lock_irqsave(&mappass->copy_lock, flags);
788 if (mappass->reqcopy.cmd != 0) {
789 ret = -EINTR;
790 goto out;
791 }
792
793 mappass->reqcopy = *req;
794 icsk = inet_csk(mappass->sock->sk);
795 queue = &icsk->icsk_accept_queue;
796 data = READ_ONCE(queue->rskq_accept_head) != NULL;
797 if (data) {
798 mappass->reqcopy.cmd = 0;
799 ret = 0;
800 goto out;
801 }
802 spin_unlock_irqrestore(&mappass->copy_lock, flags);
803
804 /* Tell the caller we don't need to send back a notification yet */
805 return -1;
806
807out:
808 spin_unlock_irqrestore(&mappass->copy_lock, flags);
809
810 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
811 rsp->req_id = req->req_id;
812 rsp->cmd = req->cmd;
813 rsp->u.poll.id = req->u.poll.id;
814 rsp->ret = ret;
815 return 0;
816}
817
818static int pvcalls_back_handle_cmd(struct xenbus_device *dev,
819 struct xen_pvcalls_request *req)
820{
821 int ret = 0;
822
823 switch (req->cmd) {
824 case PVCALLS_SOCKET:
825 ret = pvcalls_back_socket(dev, req);
826 break;
827 case PVCALLS_CONNECT:
828 ret = pvcalls_back_connect(dev, req);
829 break;
830 case PVCALLS_RELEASE:
831 ret = pvcalls_back_release(dev, req);
832 break;
833 case PVCALLS_BIND:
834 ret = pvcalls_back_bind(dev, req);
835 break;
836 case PVCALLS_LISTEN:
837 ret = pvcalls_back_listen(dev, req);
838 break;
839 case PVCALLS_ACCEPT:
840 ret = pvcalls_back_accept(dev, req);
841 break;
842 case PVCALLS_POLL:
843 ret = pvcalls_back_poll(dev, req);
844 break;
845 default:
846 {
847 struct pvcalls_fedata *fedata;
848 struct xen_pvcalls_response *rsp;
849
850 fedata = dev_get_drvdata(&dev->dev);
851 rsp = RING_GET_RESPONSE(
852 &fedata->ring, fedata->ring.rsp_prod_pvt++);
853 rsp->req_id = req->req_id;
854 rsp->cmd = req->cmd;
855 rsp->ret = -ENOTSUPP;
856 break;
857 }
858 }
859 return ret;
860}
861
862static void pvcalls_back_work(struct pvcalls_fedata *fedata)
863{
864 int notify, notify_all = 0, more = 1;
865 struct xen_pvcalls_request req;
866 struct xenbus_device *dev = fedata->dev;
867
868 while (more) {
869 while (RING_HAS_UNCONSUMED_REQUESTS(&fedata->ring)) {
870 RING_COPY_REQUEST(&fedata->ring,
871 fedata->ring.req_cons++,
872 &req);
873
874 if (!pvcalls_back_handle_cmd(dev, &req)) {
875 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(
876 &fedata->ring, notify);
877 notify_all += notify;
878 }
879 }
880
881 if (notify_all) {
882 notify_remote_via_irq(fedata->irq);
883 notify_all = 0;
884 }
885
886 RING_FINAL_CHECK_FOR_REQUESTS(&fedata->ring, more);
887 }
888}
889
890static irqreturn_t pvcalls_back_event(int irq, void *dev_id)
891{
892 struct xenbus_device *dev = dev_id;
893 struct pvcalls_fedata *fedata = NULL;
894 unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
895
896 if (dev) {
897 fedata = dev_get_drvdata(&dev->dev);
898 if (fedata) {
899 pvcalls_back_work(fedata);
900 eoi_flags = 0;
901 }
902 }
903
904 xen_irq_lateeoi(irq, eoi_flags);
905
906 return IRQ_HANDLED;
907}
908
909static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map)
910{
911 struct sock_mapping *map = sock_map;
912 struct pvcalls_ioworker *iow;
913
914 if (map == NULL || map->sock == NULL || map->sock->sk == NULL ||
915 map->sock->sk->sk_user_data != map) {
916 xen_irq_lateeoi(irq, 0);
917 return IRQ_HANDLED;
918 }
919
920 iow = &map->ioworker;
921
922 atomic_inc(&map->write);
923 atomic_inc(&map->eoi);
924 atomic_inc(&map->io);
925 queue_work(iow->wq, &iow->register_work);
926
927 return IRQ_HANDLED;
928}
929
930static int backend_connect(struct xenbus_device *dev)
931{
932 int err;
933 evtchn_port_t evtchn;
934 grant_ref_t ring_ref;
935 struct pvcalls_fedata *fedata = NULL;
936
937 fedata = kzalloc(sizeof(struct pvcalls_fedata), GFP_KERNEL);
938 if (!fedata)
939 return -ENOMEM;
940
941 fedata->irq = -1;
942 err = xenbus_scanf(XBT_NIL, dev->otherend, "port", "%u",
943 &evtchn);
944 if (err != 1) {
945 err = -EINVAL;
946 xenbus_dev_fatal(dev, err, "reading %s/event-channel",
947 dev->otherend);
948 goto error;
949 }
950
951 err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", "%u", &ring_ref);
952 if (err != 1) {
953 err = -EINVAL;
954 xenbus_dev_fatal(dev, err, "reading %s/ring-ref",
955 dev->otherend);
956 goto error;
957 }
958
959 err = bind_interdomain_evtchn_to_irq_lateeoi(dev, evtchn);
960 if (err < 0)
961 goto error;
962 fedata->irq = err;
963
964 err = request_threaded_irq(fedata->irq, NULL, pvcalls_back_event,
965 IRQF_ONESHOT, "pvcalls-back", dev);
966 if (err < 0)
967 goto error;
968
969 err = xenbus_map_ring_valloc(dev, &ring_ref, 1,
970 (void **)&fedata->sring);
971 if (err < 0)
972 goto error;
973
974 BACK_RING_INIT(&fedata->ring, fedata->sring, XEN_PAGE_SIZE * 1);
975 fedata->dev = dev;
976
977 INIT_LIST_HEAD(&fedata->socket_mappings);
978 INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL);
979 sema_init(&fedata->socket_lock, 1);
980 dev_set_drvdata(&dev->dev, fedata);
981
982 down(&pvcalls_back_global.frontends_lock);
983 list_add_tail(&fedata->list, &pvcalls_back_global.frontends);
984 up(&pvcalls_back_global.frontends_lock);
985
986 return 0;
987
988 error:
989 if (fedata->irq >= 0)
990 unbind_from_irqhandler(fedata->irq, dev);
991 if (fedata->sring != NULL)
992 xenbus_unmap_ring_vfree(dev, fedata->sring);
993 kfree(fedata);
994 return err;
995}
996
997static int backend_disconnect(struct xenbus_device *dev)
998{
999 struct pvcalls_fedata *fedata;
1000 struct sock_mapping *map, *n;
1001 struct sockpass_mapping *mappass;
1002 struct radix_tree_iter iter;
1003 void **slot;
1004
1005
1006 fedata = dev_get_drvdata(&dev->dev);
1007
1008 down(&fedata->socket_lock);
1009 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {
1010 list_del(&map->list);
1011 pvcalls_back_release_active(dev, fedata, map);
1012 }
1013
1014 radix_tree_for_each_slot(slot, &fedata->socketpass_mappings, &iter, 0) {
1015 mappass = radix_tree_deref_slot(slot);
1016 if (!mappass)
1017 continue;
1018 if (radix_tree_exception(mappass)) {
1019 if (radix_tree_deref_retry(mappass))
1020 slot = radix_tree_iter_retry(&iter);
1021 } else {
1022 radix_tree_delete(&fedata->socketpass_mappings,
1023 mappass->id);
1024 pvcalls_back_release_passive(dev, fedata, mappass);
1025 }
1026 }
1027 up(&fedata->socket_lock);
1028
1029 unbind_from_irqhandler(fedata->irq, dev);
1030 xenbus_unmap_ring_vfree(dev, fedata->sring);
1031
1032 list_del(&fedata->list);
1033 kfree(fedata);
1034 dev_set_drvdata(&dev->dev, NULL);
1035
1036 return 0;
1037}
1038
1039static int pvcalls_back_probe(struct xenbus_device *dev,
1040 const struct xenbus_device_id *id)
1041{
1042 int err, abort;
1043 struct xenbus_transaction xbt;
1044
1045again:
1046 abort = 1;
1047
1048 err = xenbus_transaction_start(&xbt);
1049 if (err) {
1050 pr_warn("%s cannot create xenstore transaction\n", __func__);
1051 return err;
1052 }
1053
1054 err = xenbus_printf(xbt, dev->nodename, "versions", "%s",
1055 PVCALLS_VERSIONS);
1056 if (err) {
1057 pr_warn("%s write out 'versions' failed\n", __func__);
1058 goto abort;
1059 }
1060
1061 err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u",
1062 MAX_RING_ORDER);
1063 if (err) {
1064 pr_warn("%s write out 'max-page-order' failed\n", __func__);
1065 goto abort;
1066 }
1067
1068 err = xenbus_printf(xbt, dev->nodename, "function-calls",
1069 XENBUS_FUNCTIONS_CALLS);
1070 if (err) {
1071 pr_warn("%s write out 'function-calls' failed\n", __func__);
1072 goto abort;
1073 }
1074
1075 abort = 0;
1076abort:
1077 err = xenbus_transaction_end(xbt, abort);
1078 if (err) {
1079 if (err == -EAGAIN && !abort)
1080 goto again;
1081 pr_warn("%s cannot complete xenstore transaction\n", __func__);
1082 return err;
1083 }
1084
1085 if (abort)
1086 return -EFAULT;
1087
1088 xenbus_switch_state(dev, XenbusStateInitWait);
1089
1090 return 0;
1091}
1092
1093static void set_backend_state(struct xenbus_device *dev,
1094 enum xenbus_state state)
1095{
1096 while (dev->state != state) {
1097 switch (dev->state) {
1098 case XenbusStateClosed:
1099 switch (state) {
1100 case XenbusStateInitWait:
1101 case XenbusStateConnected:
1102 xenbus_switch_state(dev, XenbusStateInitWait);
1103 break;
1104 case XenbusStateClosing:
1105 xenbus_switch_state(dev, XenbusStateClosing);
1106 break;
1107 default:
1108 WARN_ON(1);
1109 }
1110 break;
1111 case XenbusStateInitWait:
1112 case XenbusStateInitialised:
1113 switch (state) {
1114 case XenbusStateConnected:
1115 if (backend_connect(dev))
1116 return;
1117 xenbus_switch_state(dev, XenbusStateConnected);
1118 break;
1119 case XenbusStateClosing:
1120 case XenbusStateClosed:
1121 xenbus_switch_state(dev, XenbusStateClosing);
1122 break;
1123 default:
1124 WARN_ON(1);
1125 }
1126 break;
1127 case XenbusStateConnected:
1128 switch (state) {
1129 case XenbusStateInitWait:
1130 case XenbusStateClosing:
1131 case XenbusStateClosed:
1132 down(&pvcalls_back_global.frontends_lock);
1133 backend_disconnect(dev);
1134 up(&pvcalls_back_global.frontends_lock);
1135 xenbus_switch_state(dev, XenbusStateClosing);
1136 break;
1137 default:
1138 WARN_ON(1);
1139 }
1140 break;
1141 case XenbusStateClosing:
1142 switch (state) {
1143 case XenbusStateInitWait:
1144 case XenbusStateConnected:
1145 case XenbusStateClosed:
1146 xenbus_switch_state(dev, XenbusStateClosed);
1147 break;
1148 default:
1149 WARN_ON(1);
1150 }
1151 break;
1152 default:
1153 WARN_ON(1);
1154 }
1155 }
1156}
1157
1158static void pvcalls_back_changed(struct xenbus_device *dev,
1159 enum xenbus_state frontend_state)
1160{
1161 switch (frontend_state) {
1162 case XenbusStateInitialising:
1163 set_backend_state(dev, XenbusStateInitWait);
1164 break;
1165
1166 case XenbusStateInitialised:
1167 case XenbusStateConnected:
1168 set_backend_state(dev, XenbusStateConnected);
1169 break;
1170
1171 case XenbusStateClosing:
1172 set_backend_state(dev, XenbusStateClosing);
1173 break;
1174
1175 case XenbusStateClosed:
1176 set_backend_state(dev, XenbusStateClosed);
1177 if (xenbus_dev_is_online(dev))
1178 break;
1179 device_unregister(&dev->dev);
1180 break;
1181 case XenbusStateUnknown:
1182 set_backend_state(dev, XenbusStateClosed);
1183 device_unregister(&dev->dev);
1184 break;
1185
1186 default:
1187 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1188 frontend_state);
1189 break;
1190 }
1191}
1192
1193static void pvcalls_back_remove(struct xenbus_device *dev)
1194{
1195}
1196
1197static int pvcalls_back_uevent(const struct xenbus_device *xdev,
1198 struct kobj_uevent_env *env)
1199{
1200 return 0;
1201}
1202
1203static const struct xenbus_device_id pvcalls_back_ids[] = {
1204 { "pvcalls" },
1205 { "" }
1206};
1207
1208static struct xenbus_driver pvcalls_back_driver = {
1209 .ids = pvcalls_back_ids,
1210 .probe = pvcalls_back_probe,
1211 .remove = pvcalls_back_remove,
1212 .uevent = pvcalls_back_uevent,
1213 .otherend_changed = pvcalls_back_changed,
1214};
1215
1216static int __init pvcalls_back_init(void)
1217{
1218 int ret;
1219
1220 if (!xen_domain())
1221 return -ENODEV;
1222
1223 ret = xenbus_register_backend(&pvcalls_back_driver);
1224 if (ret < 0)
1225 return ret;
1226
1227 sema_init(&pvcalls_back_global.frontends_lock, 1);
1228 INIT_LIST_HEAD(&pvcalls_back_global.frontends);
1229 return 0;
1230}
1231module_init(pvcalls_back_init);
1232
1233static void __exit pvcalls_back_fin(void)
1234{
1235 struct pvcalls_fedata *fedata, *nfedata;
1236
1237 down(&pvcalls_back_global.frontends_lock);
1238 list_for_each_entry_safe(fedata, nfedata,
1239 &pvcalls_back_global.frontends, list) {
1240 backend_disconnect(fedata->dev);
1241 }
1242 up(&pvcalls_back_global.frontends_lock);
1243
1244 xenbus_unregister_driver(&pvcalls_back_driver);
1245}
1246
1247module_exit(pvcalls_back_fin);
1248
1249MODULE_DESCRIPTION("Xen PV Calls backend driver");
1250MODULE_AUTHOR("Stefano Stabellini <sstabellini@kernel.org>");
1251MODULE_LICENSE("GPL");