?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
x86/topology: Fix function name in documentation
[cris-mirror.git] / drivers / xen / pvcalls-front.c
blobaedbee3b28386a1cc1625334fe431875bd787277
1 /*
2 * (c) 2017 Stefano Stabellini <stefano@aporeto.com>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 */
14
15 #include <linux/module.h>
16 #include <linux/net.h>
17 #include <linux/socket.h>
18
19 #include <net/sock.h>
20
21 #include <xen/events.h>
22 #include <xen/grant_table.h>
23 #include <xen/xen.h>
24 #include <xen/xenbus.h>
25 #include <xen/interface/io/pvcalls.h>
26
27 #include "pvcalls-front.h"
28
29 #define PVCALLS_INVALID_ID UINT_MAX
30 #define PVCALLS_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER
31 #define PVCALLS_NR_RSP_PER_RING __CONST_RING_SIZE(xen_pvcalls, XEN_PAGE_SIZE)
32 #define PVCALLS_FRONT_MAX_SPIN 5000
33
34 struct pvcalls_bedata {
35 struct xen_pvcalls_front_ring ring;
36 grant_ref_t ref;
37 int irq;
38
39 struct list_head socket_mappings;
40 spinlock_t socket_lock;
41
42 wait_queue_head_t inflight_req;
43 struct xen_pvcalls_response rsp[PVCALLS_NR_RSP_PER_RING];
44 };
45 /* Only one front/back connection supported. */
46 static struct xenbus_device *pvcalls_front_dev;
47 static atomic_t pvcalls_refcount;
48
49 /* first increment refcount, then proceed */
50 #define pvcalls_enter() { \
51 atomic_inc(&pvcalls_refcount); \
52 }
53
54 /* first complete other operations, then decrement refcount */
55 #define pvcalls_exit() { \
56 atomic_dec(&pvcalls_refcount); \
57 }
58
59 struct sock_mapping {
60 bool active_socket;
61 struct list_head list;
62 struct socket *sock;
63 atomic_t refcount;
64 union {
65 struct {
66 int irq;
67 grant_ref_t ref;
68 struct pvcalls_data_intf *ring;
69 struct pvcalls_data data;
70 struct mutex in_mutex;
71 struct mutex out_mutex;
72
73 wait_queue_head_t inflight_conn_req;
74 } active;
75 struct {
76 /* Socket status */
77 #define PVCALLS_STATUS_UNINITALIZED 0
78 #define PVCALLS_STATUS_BIND 1
79 #define PVCALLS_STATUS_LISTEN 2
80 uint8_t status;
81 /*
82 * Internal state-machine flags.
83 * Only one accept operation can be inflight for a socket.
84 * Only one poll operation can be inflight for a given socket.
85 */
86 #define PVCALLS_FLAG_ACCEPT_INFLIGHT 0
87 #define PVCALLS_FLAG_POLL_INFLIGHT 1
88 #define PVCALLS_FLAG_POLL_RET 2
89 uint8_t flags;
90 uint32_t inflight_req_id;
91 struct sock_mapping *accept_map;
92 wait_queue_head_t inflight_accept_req;
93 } passive;
94 };
95 };
96
97 static inline struct sock_mapping *pvcalls_enter_sock(struct socket *sock)
98 {
99 struct sock_mapping *map;
100
101 if (!pvcalls_front_dev ||
102 dev_get_drvdata(&pvcalls_front_dev->dev) == NULL)
103 return ERR_PTR(-ENOTCONN);
104
105 map = (struct sock_mapping *)sock->sk->sk_send_head;
106 if (map == NULL)
107 return ERR_PTR(-ENOTSOCK);
108
109 pvcalls_enter();
110 atomic_inc(&map->refcount);
111 return map;
112 }
113
114 static inline void pvcalls_exit_sock(struct socket *sock)
115 {
116 struct sock_mapping *map;
117
118 map = (struct sock_mapping *)sock->sk->sk_send_head;
119 atomic_dec(&map->refcount);
120 pvcalls_exit();
121 }
122
123 static inline int get_request(struct pvcalls_bedata *bedata, int *req_id)
124 {
125 *req_id = bedata->ring.req_prod_pvt & (RING_SIZE(&bedata->ring) - 1);
126 if (RING_FULL(&bedata->ring) ||
127 bedata->rsp[*req_id].req_id != PVCALLS_INVALID_ID)
128 return -EAGAIN;
129 return 0;
130 }
131
132 static bool pvcalls_front_write_todo(struct sock_mapping *map)
133 {
134 struct pvcalls_data_intf *intf = map->active.ring;
135 RING_IDX cons, prod, size = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
136 int32_t error;
137
138 error = intf->out_error;
139 if (error == -ENOTCONN)
140 return false;
141 if (error != 0)
142 return true;
143
144 cons = intf->out_cons;
145 prod = intf->out_prod;
146 return !!(size - pvcalls_queued(prod, cons, size));
147 }
148
149 static bool pvcalls_front_read_todo(struct sock_mapping *map)
150 {
151 struct pvcalls_data_intf *intf = map->active.ring;
152 RING_IDX cons, prod;
153 int32_t error;
154
155 cons = intf->in_cons;
156 prod = intf->in_prod;
157 error = intf->in_error;
158 return (error != 0 ||
159 pvcalls_queued(prod, cons,
160 XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER)) != 0);
161 }
162
163 static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
164 {
165 struct xenbus_device *dev = dev_id;
166 struct pvcalls_bedata *bedata;
167 struct xen_pvcalls_response *rsp;
168 uint8_t *src, *dst;
169 int req_id = 0, more = 0, done = 0;
170
171 if (dev == NULL)
172 return IRQ_HANDLED;
173
174 pvcalls_enter();
175 bedata = dev_get_drvdata(&dev->dev);
176 if (bedata == NULL) {
177 pvcalls_exit();
178 return IRQ_HANDLED;
179 }
180
181 again:
182 while (RING_HAS_UNCONSUMED_RESPONSES(&bedata->ring)) {
183 rsp = RING_GET_RESPONSE(&bedata->ring, bedata->ring.rsp_cons);
184
185 req_id = rsp->req_id;
186 if (rsp->cmd == PVCALLS_POLL) {
187 struct sock_mapping *map = (struct sock_mapping *)(uintptr_t)
188 rsp->u.poll.id;
189
190 clear_bit(PVCALLS_FLAG_POLL_INFLIGHT,
191 (void *)&map->passive.flags);
192 /*
193 * clear INFLIGHT, then set RET. It pairs with
194 * the checks at the beginning of
195 * pvcalls_front_poll_passive.
196 */
197 smp_wmb();
198 set_bit(PVCALLS_FLAG_POLL_RET,
199 (void *)&map->passive.flags);
200 } else {
201 dst = (uint8_t *)&bedata->rsp[req_id] +
202 sizeof(rsp->req_id);
203 src = (uint8_t *)rsp + sizeof(rsp->req_id);
204 memcpy(dst, src, sizeof(*rsp) - sizeof(rsp->req_id));
205 /*
206 * First copy the rest of the data, then req_id. It is
207 * paired with the barrier when accessing bedata->rsp.
208 */
209 smp_wmb();
210 bedata->rsp[req_id].req_id = req_id;
211 }
212
213 done = 1;
214 bedata->ring.rsp_cons++;
215 }
216
217 RING_FINAL_CHECK_FOR_RESPONSES(&bedata->ring, more);
218 if (more)
219 goto again;
220 if (done)
221 wake_up(&bedata->inflight_req);
222 pvcalls_exit();
223 return IRQ_HANDLED;
224 }
225
226 static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
227 struct sock_mapping *map)
228 {
229 int i;
230
231 unbind_from_irqhandler(map->active.irq, map);
232
233 spin_lock(&bedata->socket_lock);
234 if (!list_empty(&map->list))
235 list_del_init(&map->list);
236 spin_unlock(&bedata->socket_lock);
237
238 for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++)
239 gnttab_end_foreign_access(map->active.ring->ref[i], 0, 0);
240 gnttab_end_foreign_access(map->active.ref, 0, 0);
241 free_page((unsigned long)map->active.ring);
242
243 kfree(map);
244 }
245
246 static irqreturn_t pvcalls_front_conn_handler(int irq, void *sock_map)
247 {
248 struct sock_mapping *map = sock_map;
249
250 if (map == NULL)
251 return IRQ_HANDLED;
252
253 wake_up_interruptible(&map->active.inflight_conn_req);
254
255 return IRQ_HANDLED;
256 }
257
258 int pvcalls_front_socket(struct socket *sock)
259 {
260 struct pvcalls_bedata *bedata;
261 struct sock_mapping *map = NULL;
262 struct xen_pvcalls_request *req;
263 int notify, req_id, ret;
264
265 /*
266 * PVCalls only supports domain AF_INET,
267 * type SOCK_STREAM and protocol 0 sockets for now.
268 *
269 * Check socket type here, AF_INET and protocol checks are done
270 * by the caller.
271 */
272 if (sock->type != SOCK_STREAM)
273 return -EOPNOTSUPP;
274
275 pvcalls_enter();
276 if (!pvcalls_front_dev) {
277 pvcalls_exit();
278 return -EACCES;
279 }
280 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
281
282 map = kzalloc(sizeof(*map), GFP_KERNEL);
283 if (map == NULL) {
284 pvcalls_exit();
285 return -ENOMEM;
286 }
287
288 spin_lock(&bedata->socket_lock);
289
290 ret = get_request(bedata, &req_id);
291 if (ret < 0) {
292 kfree(map);
293 spin_unlock(&bedata->socket_lock);
294 pvcalls_exit();
295 return ret;
296 }
297
298 /*
299 * sock->sk->sk_send_head is not used for ip sockets: reuse the
300 * field to store a pointer to the struct sock_mapping
301 * corresponding to the socket. This way, we can easily get the
302 * struct sock_mapping from the struct socket.
303 */
304 sock->sk->sk_send_head = (void *)map;
305 list_add_tail(&map->list, &bedata->socket_mappings);
306
307 req = RING_GET_REQUEST(&bedata->ring, req_id);
308 req->req_id = req_id;
309 req->cmd = PVCALLS_SOCKET;
310 req->u.socket.id = (uintptr_t) map;
311 req->u.socket.domain = AF_INET;
312 req->u.socket.type = SOCK_STREAM;
313 req->u.socket.protocol = IPPROTO_IP;
314
315 bedata->ring.req_prod_pvt++;
316 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
317 spin_unlock(&bedata->socket_lock);
318 if (notify)
319 notify_remote_via_irq(bedata->irq);
320
321 wait_event(bedata->inflight_req,
322 READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
323
324 /* read req_id, then the content */
325 smp_rmb();
326 ret = bedata->rsp[req_id].ret;
327 bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
328
329 pvcalls_exit();
330 return ret;
331 }
332
333 static int create_active(struct sock_mapping *map, int *evtchn)
334 {
335 void *bytes;
336 int ret = -ENOMEM, irq = -1, i;
337
338 *evtchn = -1;
339 init_waitqueue_head(&map->active.inflight_conn_req);
340
341 map->active.ring = (struct pvcalls_data_intf *)
342 __get_free_page(GFP_KERNEL | __GFP_ZERO);
343 if (map->active.ring == NULL)
344 goto out_error;
345 map->active.ring->ring_order = PVCALLS_RING_ORDER;
346 bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
347 PVCALLS_RING_ORDER);
348 if (bytes == NULL)
349 goto out_error;
350 for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++)
351 map->active.ring->ref[i] = gnttab_grant_foreign_access(
352 pvcalls_front_dev->otherend_id,
353 pfn_to_gfn(virt_to_pfn(bytes) + i), 0);
354
355 map->active.ref = gnttab_grant_foreign_access(
356 pvcalls_front_dev->otherend_id,
357 pfn_to_gfn(virt_to_pfn((void *)map->active.ring)), 0);
358
359 map->active.data.in = bytes;
360 map->active.data.out = bytes +
361 XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
362
363 ret = xenbus_alloc_evtchn(pvcalls_front_dev, evtchn);
364 if (ret)
365 goto out_error;
366 irq = bind_evtchn_to_irqhandler(*evtchn, pvcalls_front_conn_handler,
367 0, "pvcalls-frontend", map);
368 if (irq < 0) {
369 ret = irq;
370 goto out_error;
371 }
372
373 map->active.irq = irq;
374 map->active_socket = true;
375 mutex_init(&map->active.in_mutex);
376 mutex_init(&map->active.out_mutex);
377
378 return 0;
379
380 out_error:
381 if (*evtchn >= 0)
382 xenbus_free_evtchn(pvcalls_front_dev, *evtchn);
383 kfree(map->active.data.in);
384 kfree(map->active.ring);
385 return ret;
386 }
387
388 int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr,
389 int addr_len, int flags)
390 {
391 struct pvcalls_bedata *bedata;
392 struct sock_mapping *map = NULL;
393 struct xen_pvcalls_request *req;
394 int notify, req_id, ret, evtchn;
395
396 if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM)
397 return -EOPNOTSUPP;
398
399 map = pvcalls_enter_sock(sock);
400 if (IS_ERR(map))
401 return PTR_ERR(map);
402
403 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
404
405 spin_lock(&bedata->socket_lock);
406 ret = get_request(bedata, &req_id);
407 if (ret < 0) {
408 spin_unlock(&bedata->socket_lock);
409 pvcalls_exit_sock(sock);
410 return ret;
411 }
412 ret = create_active(map, &evtchn);
413 if (ret < 0) {
414 spin_unlock(&bedata->socket_lock);
415 pvcalls_exit_sock(sock);
416 return ret;
417 }
418
419 req = RING_GET_REQUEST(&bedata->ring, req_id);
420 req->req_id = req_id;
421 req->cmd = PVCALLS_CONNECT;
422 req->u.connect.id = (uintptr_t)map;
423 req->u.connect.len = addr_len;
424 req->u.connect.flags = flags;
425 req->u.connect.ref = map->active.ref;
426 req->u.connect.evtchn = evtchn;
427 memcpy(req->u.connect.addr, addr, sizeof(*addr));
428
429 map->sock = sock;
430
431 bedata->ring.req_prod_pvt++;
432 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
433 spin_unlock(&bedata->socket_lock);
434
435 if (notify)
436 notify_remote_via_irq(bedata->irq);
437
438 wait_event(bedata->inflight_req,
439 READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
440
441 /* read req_id, then the content */
442 smp_rmb();
443 ret = bedata->rsp[req_id].ret;
444 bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
445 pvcalls_exit_sock(sock);
446 return ret;
447 }
448
449 static int __write_ring(struct pvcalls_data_intf *intf,
450 struct pvcalls_data *data,
451 struct iov_iter *msg_iter,
452 int len)
453 {
454 RING_IDX cons, prod, size, masked_prod, masked_cons;
455 RING_IDX array_size = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
456 int32_t error;
457
458 error = intf->out_error;
459 if (error < 0)
460 return error;
461 cons = intf->out_cons;
462 prod = intf->out_prod;
463 /* read indexes before continuing */
464 virt_mb();
465
466 size = pvcalls_queued(prod, cons, array_size);
467 if (size >= array_size)
468 return -EINVAL;
469 if (len > array_size - size)
470 len = array_size - size;
471
472 masked_prod = pvcalls_mask(prod, array_size);
473 masked_cons = pvcalls_mask(cons, array_size);
474
475 if (masked_prod < masked_cons) {
476 len = copy_from_iter(data->out + masked_prod, len, msg_iter);
477 } else {
478 if (len > array_size - masked_prod) {
479 int ret = copy_from_iter(data->out + masked_prod,
480 array_size - masked_prod, msg_iter);
481 if (ret != array_size - masked_prod) {
482 len = ret;
483 goto out;
484 }
485 len = ret + copy_from_iter(data->out, len - ret, msg_iter);
486 } else {
487 len = copy_from_iter(data->out + masked_prod, len, msg_iter);
488 }
489 }
490 out:
491 /* write to ring before updating pointer */
492 virt_wmb();
493 intf->out_prod += len;
494
495 return len;
496 }
497
498 int pvcalls_front_sendmsg(struct socket *sock, struct msghdr *msg,
499 size_t len)
500 {
501 struct pvcalls_bedata *bedata;
502 struct sock_mapping *map;
503 int sent, tot_sent = 0;
504 int count = 0, flags;
505
506 flags = msg->msg_flags;
507 if (flags & (MSG_CONFIRM|MSG_DONTROUTE|MSG_EOR|MSG_OOB))
508 return -EOPNOTSUPP;
509
510 map = pvcalls_enter_sock(sock);
511 if (IS_ERR(map))
512 return PTR_ERR(map);
513 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
514
515 mutex_lock(&map->active.out_mutex);
516 if ((flags & MSG_DONTWAIT) && !pvcalls_front_write_todo(map)) {
517 mutex_unlock(&map->active.out_mutex);
518 pvcalls_exit_sock(sock);
519 return -EAGAIN;
520 }
521 if (len > INT_MAX)
522 len = INT_MAX;
523
524 again:
525 count++;
526 sent = __write_ring(map->active.ring,
527 &map->active.data, &msg->msg_iter,
528 len);
529 if (sent > 0) {
530 len -= sent;
531 tot_sent += sent;
532 notify_remote_via_irq(map->active.irq);
533 }
534 if (sent >= 0 && len > 0 && count < PVCALLS_FRONT_MAX_SPIN)
535 goto again;
536 if (sent < 0)
537 tot_sent = sent;
538
539 mutex_unlock(&map->active.out_mutex);
540 pvcalls_exit_sock(sock);
541 return tot_sent;
542 }
543
544 static int __read_ring(struct pvcalls_data_intf *intf,
545 struct pvcalls_data *data,
546 struct iov_iter *msg_iter,
547 size_t len, int flags)
548 {
549 RING_IDX cons, prod, size, masked_prod, masked_cons;
550 RING_IDX array_size = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
551 int32_t error;
552
553 cons = intf->in_cons;
554 prod = intf->in_prod;
555 error = intf->in_error;
556 /* get pointers before reading from the ring */
557 virt_rmb();
558 if (error < 0)
559 return error;
560
561 size = pvcalls_queued(prod, cons, array_size);
562 masked_prod = pvcalls_mask(prod, array_size);
563 masked_cons = pvcalls_mask(cons, array_size);
564
565 if (size == 0)
566 return 0;
567
568 if (len > size)
569 len = size;
570
571 if (masked_prod > masked_cons) {
572 len = copy_to_iter(data->in + masked_cons, len, msg_iter);
573 } else {
574 if (len > (array_size - masked_cons)) {
575 int ret = copy_to_iter(data->in + masked_cons,
576 array_size - masked_cons, msg_iter);
577 if (ret != array_size - masked_cons) {
578 len = ret;
579 goto out;
580 }
581 len = ret + copy_to_iter(data->in, len - ret, msg_iter);
582 } else {
583 len = copy_to_iter(data->in + masked_cons, len, msg_iter);
584 }
585 }
586 out:
587 /* read data from the ring before increasing the index */
588 virt_mb();
589 if (!(flags & MSG_PEEK))
590 intf->in_cons += len;
591
592 return len;
593 }
594
595 int pvcalls_front_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
596 int flags)
597 {
598 struct pvcalls_bedata *bedata;
599 int ret;
600 struct sock_mapping *map;
601
602 if (flags & (MSG_CMSG_CLOEXEC|MSG_ERRQUEUE|MSG_OOB|MSG_TRUNC))
603 return -EOPNOTSUPP;
604
605 map = pvcalls_enter_sock(sock);
606 if (IS_ERR(map))
607 return PTR_ERR(map);
608 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
609
610 mutex_lock(&map->active.in_mutex);
611 if (len > XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER))
612 len = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
613
614 while (!(flags & MSG_DONTWAIT) && !pvcalls_front_read_todo(map)) {
615 wait_event_interruptible(map->active.inflight_conn_req,
616 pvcalls_front_read_todo(map));
617 }
618 ret = __read_ring(map->active.ring, &map->active.data,
619 &msg->msg_iter, len, flags);
620
621 if (ret > 0)
622 notify_remote_via_irq(map->active.irq);
623 if (ret == 0)
624 ret = (flags & MSG_DONTWAIT) ? -EAGAIN : 0;
625 if (ret == -ENOTCONN)
626 ret = 0;
627
628 mutex_unlock(&map->active.in_mutex);
629 pvcalls_exit_sock(sock);
630 return ret;
631 }
632
633 int pvcalls_front_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
634 {
635 struct pvcalls_bedata *bedata;
636 struct sock_mapping *map = NULL;
637 struct xen_pvcalls_request *req;
638 int notify, req_id, ret;
639
640 if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM)
641 return -EOPNOTSUPP;
642
643 map = pvcalls_enter_sock(sock);
644 if (IS_ERR(map))
645 return PTR_ERR(map);
646 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
647
648 spin_lock(&bedata->socket_lock);
649 ret = get_request(bedata, &req_id);
650 if (ret < 0) {
651 spin_unlock(&bedata->socket_lock);
652 pvcalls_exit_sock(sock);
653 return ret;
654 }
655 req = RING_GET_REQUEST(&bedata->ring, req_id);
656 req->req_id = req_id;
657 map->sock = sock;
658 req->cmd = PVCALLS_BIND;
659 req->u.bind.id = (uintptr_t)map;
660 memcpy(req->u.bind.addr, addr, sizeof(*addr));
661 req->u.bind.len = addr_len;
662
663 init_waitqueue_head(&map->passive.inflight_accept_req);
664
665 map->active_socket = false;
666
667 bedata->ring.req_prod_pvt++;
668 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
669 spin_unlock(&bedata->socket_lock);
670 if (notify)
671 notify_remote_via_irq(bedata->irq);
672
673 wait_event(bedata->inflight_req,
674 READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
675
676 /* read req_id, then the content */
677 smp_rmb();
678 ret = bedata->rsp[req_id].ret;
679 bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
680
681 map->passive.status = PVCALLS_STATUS_BIND;
682 pvcalls_exit_sock(sock);
683 return 0;
684 }
685
686 int pvcalls_front_listen(struct socket *sock, int backlog)
687 {
688 struct pvcalls_bedata *bedata;
689 struct sock_mapping *map;
690 struct xen_pvcalls_request *req;
691 int notify, req_id, ret;
692
693 map = pvcalls_enter_sock(sock);
694 if (IS_ERR(map))
695 return PTR_ERR(map);
696 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
697
698 if (map->passive.status != PVCALLS_STATUS_BIND) {
699 pvcalls_exit_sock(sock);
700 return -EOPNOTSUPP;
701 }
702
703 spin_lock(&bedata->socket_lock);
704 ret = get_request(bedata, &req_id);
705 if (ret < 0) {
706 spin_unlock(&bedata->socket_lock);
707 pvcalls_exit_sock(sock);
708 return ret;
709 }
710 req = RING_GET_REQUEST(&bedata->ring, req_id);
711 req->req_id = req_id;
712 req->cmd = PVCALLS_LISTEN;
713 req->u.listen.id = (uintptr_t) map;
714 req->u.listen.backlog = backlog;
715
716 bedata->ring.req_prod_pvt++;
717 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
718 spin_unlock(&bedata->socket_lock);
719 if (notify)
720 notify_remote_via_irq(bedata->irq);
721
722 wait_event(bedata->inflight_req,
723 READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
724
725 /* read req_id, then the content */
726 smp_rmb();
727 ret = bedata->rsp[req_id].ret;
728 bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
729
730 map->passive.status = PVCALLS_STATUS_LISTEN;
731 pvcalls_exit_sock(sock);
732 return ret;
733 }
734
735 int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags)
736 {
737 struct pvcalls_bedata *bedata;
738 struct sock_mapping *map;
739 struct sock_mapping *map2 = NULL;
740 struct xen_pvcalls_request *req;
741 int notify, req_id, ret, evtchn, nonblock;
742
743 map = pvcalls_enter_sock(sock);
744 if (IS_ERR(map))
745 return PTR_ERR(map);
746 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
747
748 if (map->passive.status != PVCALLS_STATUS_LISTEN) {
749 pvcalls_exit_sock(sock);
750 return -EINVAL;
751 }
752
753 nonblock = flags & SOCK_NONBLOCK;
754 /*
755 * Backend only supports 1 inflight accept request, will return
756 * errors for the others
757 */
758 if (test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
759 (void *)&map->passive.flags)) {
760 req_id = READ_ONCE(map->passive.inflight_req_id);
761 if (req_id != PVCALLS_INVALID_ID &&
762 READ_ONCE(bedata->rsp[req_id].req_id) == req_id) {
763 map2 = map->passive.accept_map;
764 goto received;
765 }
766 if (nonblock) {
767 pvcalls_exit_sock(sock);
768 return -EAGAIN;
769 }
770 if (wait_event_interruptible(map->passive.inflight_accept_req,
771 !test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
772 (void *)&map->passive.flags))) {
773 pvcalls_exit_sock(sock);
774 return -EINTR;
775 }
776 }
777
778 spin_lock(&bedata->socket_lock);
779 ret = get_request(bedata, &req_id);
780 if (ret < 0) {
781 clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
782 (void *)&map->passive.flags);
783 spin_unlock(&bedata->socket_lock);
784 pvcalls_exit_sock(sock);
785 return ret;
786 }
787 map2 = kzalloc(sizeof(*map2), GFP_ATOMIC);
788 if (map2 == NULL) {
789 clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
790 (void *)&map->passive.flags);
791 spin_unlock(&bedata->socket_lock);
792 pvcalls_exit_sock(sock);
793 return -ENOMEM;
794 }
795 ret = create_active(map2, &evtchn);
796 if (ret < 0) {
797 kfree(map2);
798 clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
799 (void *)&map->passive.flags);
800 spin_unlock(&bedata->socket_lock);
801 pvcalls_exit_sock(sock);
802 return ret;
803 }
804 list_add_tail(&map2->list, &bedata->socket_mappings);
805
806 req = RING_GET_REQUEST(&bedata->ring, req_id);
807 req->req_id = req_id;
808 req->cmd = PVCALLS_ACCEPT;
809 req->u.accept.id = (uintptr_t) map;
810 req->u.accept.ref = map2->active.ref;
811 req->u.accept.id_new = (uintptr_t) map2;
812 req->u.accept.evtchn = evtchn;
813 map->passive.accept_map = map2;
814
815 bedata->ring.req_prod_pvt++;
816 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
817 spin_unlock(&bedata->socket_lock);
818 if (notify)
819 notify_remote_via_irq(bedata->irq);
820 /* We could check if we have received a response before returning. */
821 if (nonblock) {
822 WRITE_ONCE(map->passive.inflight_req_id, req_id);
823 pvcalls_exit_sock(sock);
824 return -EAGAIN;
825 }
826
827 if (wait_event_interruptible(bedata->inflight_req,
828 READ_ONCE(bedata->rsp[req_id].req_id) == req_id)) {
829 pvcalls_exit_sock(sock);
830 return -EINTR;
831 }
832 /* read req_id, then the content */
833 smp_rmb();
834
835 received:
836 map2->sock = newsock;
837 newsock->sk = kzalloc(sizeof(*newsock->sk), GFP_KERNEL);
838 if (!newsock->sk) {
839 bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
840 map->passive.inflight_req_id = PVCALLS_INVALID_ID;
841 clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
842 (void *)&map->passive.flags);
843 pvcalls_front_free_map(bedata, map2);
844 pvcalls_exit_sock(sock);
845 return -ENOMEM;
846 }
847 newsock->sk->sk_send_head = (void *)map2;
848
849 ret = bedata->rsp[req_id].ret;
850 bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
851 map->passive.inflight_req_id = PVCALLS_INVALID_ID;
852
853 clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)&map->passive.flags);
854 wake_up(&map->passive.inflight_accept_req);
855
856 pvcalls_exit_sock(sock);
857 return ret;
858 }
859
860 static __poll_t pvcalls_front_poll_passive(struct file *file,
861 struct pvcalls_bedata *bedata,
862 struct sock_mapping *map,
863 poll_table *wait)
864 {
865 int notify, req_id, ret;
866 struct xen_pvcalls_request *req;
867
868 if (test_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
869 (void *)&map->passive.flags)) {
870 uint32_t req_id = READ_ONCE(map->passive.inflight_req_id);
871
872 if (req_id != PVCALLS_INVALID_ID &&
873 READ_ONCE(bedata->rsp[req_id].req_id) == req_id)
874 return EPOLLIN | EPOLLRDNORM;
875
876 poll_wait(file, &map->passive.inflight_accept_req, wait);
877 return 0;
878 }
879
880 if (test_and_clear_bit(PVCALLS_FLAG_POLL_RET,
881 (void *)&map->passive.flags))
882 return EPOLLIN | EPOLLRDNORM;
883
884 /*
885 * First check RET, then INFLIGHT. No barriers necessary to
886 * ensure execution ordering because of the conditional
887 * instructions creating control dependencies.
888 */
889
890 if (test_and_set_bit(PVCALLS_FLAG_POLL_INFLIGHT,
891 (void *)&map->passive.flags)) {
892 poll_wait(file, &bedata->inflight_req, wait);
893 return 0;
894 }
895
896 spin_lock(&bedata->socket_lock);
897 ret = get_request(bedata, &req_id);
898 if (ret < 0) {
899 spin_unlock(&bedata->socket_lock);
900 return ret;
901 }
902 req = RING_GET_REQUEST(&bedata->ring, req_id);
903 req->req_id = req_id;
904 req->cmd = PVCALLS_POLL;
905 req->u.poll.id = (uintptr_t) map;
906
907 bedata->ring.req_prod_pvt++;
908 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
909 spin_unlock(&bedata->socket_lock);
910 if (notify)
911 notify_remote_via_irq(bedata->irq);
912
913 poll_wait(file, &bedata->inflight_req, wait);
914 return 0;
915 }
916
917 static __poll_t pvcalls_front_poll_active(struct file *file,
918 struct pvcalls_bedata *bedata,
919 struct sock_mapping *map,
920 poll_table *wait)
921 {
922 __poll_t mask = 0;
923 int32_t in_error, out_error;
924 struct pvcalls_data_intf *intf = map->active.ring;
925
926 out_error = intf->out_error;
927 in_error = intf->in_error;
928
929 poll_wait(file, &map->active.inflight_conn_req, wait);
930 if (pvcalls_front_write_todo(map))
931 mask |= EPOLLOUT | EPOLLWRNORM;
932 if (pvcalls_front_read_todo(map))
933 mask |= EPOLLIN | EPOLLRDNORM;
934 if (in_error != 0 || out_error != 0)
935 mask |= EPOLLERR;
936
937 return mask;
938 }
939
940 __poll_t pvcalls_front_poll(struct file *file, struct socket *sock,
941 poll_table *wait)
942 {
943 struct pvcalls_bedata *bedata;
944 struct sock_mapping *map;
945 __poll_t ret;
946
947 map = pvcalls_enter_sock(sock);
948 if (IS_ERR(map))
949 return EPOLLNVAL;
950 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
951
952 if (map->active_socket)
953 ret = pvcalls_front_poll_active(file, bedata, map, wait);
954 else
955 ret = pvcalls_front_poll_passive(file, bedata, map, wait);
956 pvcalls_exit_sock(sock);
957 return ret;
958 }
959
960 int pvcalls_front_release(struct socket *sock)
961 {
962 struct pvcalls_bedata *bedata;
963 struct sock_mapping *map;
964 int req_id, notify, ret;
965 struct xen_pvcalls_request *req;
966
967 if (sock->sk == NULL)
968 return 0;
969
970 map = pvcalls_enter_sock(sock);
971 if (IS_ERR(map)) {
972 if (PTR_ERR(map) == -ENOTCONN)
973 return -EIO;
974 else
975 return 0;
976 }
977 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
978
979 spin_lock(&bedata->socket_lock);
980 ret = get_request(bedata, &req_id);
981 if (ret < 0) {
982 spin_unlock(&bedata->socket_lock);
983 pvcalls_exit_sock(sock);
984 return ret;
985 }
986 sock->sk->sk_send_head = NULL;
987
988 req = RING_GET_REQUEST(&bedata->ring, req_id);
989 req->req_id = req_id;
990 req->cmd = PVCALLS_RELEASE;
991 req->u.release.id = (uintptr_t)map;
992
993 bedata->ring.req_prod_pvt++;
994 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
995 spin_unlock(&bedata->socket_lock);
996 if (notify)
997 notify_remote_via_irq(bedata->irq);
998
999 wait_event(bedata->inflight_req,
1000 READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
1001
1002 if (map->active_socket) {
1003 /*
1004 * Set in_error and wake up inflight_conn_req to force
1005 * recvmsg waiters to exit.
1006 */
1007 map->active.ring->in_error = -EBADF;
1008 wake_up_interruptible(&map->active.inflight_conn_req);
1009
1010 /*
1011 * We need to make sure that sendmsg/recvmsg on this socket have
1012 * not started before we've cleared sk_send_head here. The
1013 * easiest way to guarantee this is to see that no pvcalls
1014 * (other than us) is in progress on this socket.
1015 */
1016 while (atomic_read(&map->refcount) > 1)
1017 cpu_relax();
1018
1019 pvcalls_front_free_map(bedata, map);
1020 } else {
1021 wake_up(&bedata->inflight_req);
1022 wake_up(&map->passive.inflight_accept_req);
1023
1024 while (atomic_read(&map->refcount) > 1)
1025 cpu_relax();
1026
1027 spin_lock(&bedata->socket_lock);
1028 list_del(&map->list);
1029 spin_unlock(&bedata->socket_lock);
1030 if (READ_ONCE(map->passive.inflight_req_id) !=
1031 PVCALLS_INVALID_ID) {
1032 pvcalls_front_free_map(bedata,
1033 map->passive.accept_map);
1034 }
1035 kfree(map);
1036 }
1037 WRITE_ONCE(bedata->rsp[req_id].req_id, PVCALLS_INVALID_ID);
1038
1039 pvcalls_exit();
1040 return 0;
1041 }
1042
1043 static const struct xenbus_device_id pvcalls_front_ids[] = {
1044 { "pvcalls" },
1045 { "" }
1046 };
1047
1048 static int pvcalls_front_remove(struct xenbus_device *dev)
1049 {
1050 struct pvcalls_bedata *bedata;
1051 struct sock_mapping *map = NULL, *n;
1052
1053 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
1054 dev_set_drvdata(&dev->dev, NULL);
1055 pvcalls_front_dev = NULL;
1056 if (bedata->irq >= 0)
1057 unbind_from_irqhandler(bedata->irq, dev);
1058
1059 list_for_each_entry_safe(map, n, &bedata->socket_mappings, list) {
1060 map->sock->sk->sk_send_head = NULL;
1061 if (map->active_socket) {
1062 map->active.ring->in_error = -EBADF;
1063 wake_up_interruptible(&map->active.inflight_conn_req);
1064 }
1065 }
1066
1067 smp_mb();
1068 while (atomic_read(&pvcalls_refcount) > 0)
1069 cpu_relax();
1070 list_for_each_entry_safe(map, n, &bedata->socket_mappings, list) {
1071 if (map->active_socket) {
1072 /* No need to lock, refcount is 0 */
1073 pvcalls_front_free_map(bedata, map);
1074 } else {
1075 list_del(&map->list);
1076 kfree(map);
1077 }
1078 }
1079 if (bedata->ref != -1)
1080 gnttab_end_foreign_access(bedata->ref, 0, 0);
1081 kfree(bedata->ring.sring);
1082 kfree(bedata);
1083 xenbus_switch_state(dev, XenbusStateClosed);
1084 return 0;
1085 }
1086
1087 static int pvcalls_front_probe(struct xenbus_device *dev,
1088 const struct xenbus_device_id *id)
1089 {
1090 int ret = -ENOMEM, evtchn, i;
1091 unsigned int max_page_order, function_calls, len;
1092 char *versions;
1093 grant_ref_t gref_head = 0;
1094 struct xenbus_transaction xbt;
1095 struct pvcalls_bedata *bedata = NULL;
1096 struct xen_pvcalls_sring *sring;
1097
1098 if (pvcalls_front_dev != NULL) {
1099 dev_err(&dev->dev, "only one PV Calls connection supported\n");
1100 return -EINVAL;
1101 }
1102
1103 versions = xenbus_read(XBT_NIL, dev->otherend, "versions", &len);
1104 if (IS_ERR(versions))
1105 return PTR_ERR(versions);
1106 if (!len)
1107 return -EINVAL;
1108 if (strcmp(versions, "1")) {
1109 kfree(versions);
1110 return -EINVAL;
1111 }
1112 kfree(versions);
1113 max_page_order = xenbus_read_unsigned(dev->otherend,
1114 "max-page-order", 0);
1115 if (max_page_order < PVCALLS_RING_ORDER)
1116 return -ENODEV;
1117 function_calls = xenbus_read_unsigned(dev->otherend,
1118 "function-calls", 0);
1119 /* See XENBUS_FUNCTIONS_CALLS in pvcalls.h */
1120 if (function_calls != 1)
1121 return -ENODEV;
1122 pr_info("%s max-page-order is %u\n", __func__, max_page_order);
1123
1124 bedata = kzalloc(sizeof(struct pvcalls_bedata), GFP_KERNEL);
1125 if (!bedata)
1126 return -ENOMEM;
1127
1128 dev_set_drvdata(&dev->dev, bedata);
1129 pvcalls_front_dev = dev;
1130 init_waitqueue_head(&bedata->inflight_req);
1131 INIT_LIST_HEAD(&bedata->socket_mappings);
1132 spin_lock_init(&bedata->socket_lock);
1133 bedata->irq = -1;
1134 bedata->ref = -1;
1135
1136 for (i = 0; i < PVCALLS_NR_RSP_PER_RING; i++)
1137 bedata->rsp[i].req_id = PVCALLS_INVALID_ID;
1138
1139 sring = (struct xen_pvcalls_sring *) __get_free_page(GFP_KERNEL |
1140 __GFP_ZERO);
1141 if (!sring)
1142 goto error;
1143 SHARED_RING_INIT(sring);
1144 FRONT_RING_INIT(&bedata->ring, sring, XEN_PAGE_SIZE);
1145
1146 ret = xenbus_alloc_evtchn(dev, &evtchn);
1147 if (ret)
1148 goto error;
1149
1150 bedata->irq = bind_evtchn_to_irqhandler(evtchn,
1151 pvcalls_front_event_handler,
1152 0, "pvcalls-frontend", dev);
1153 if (bedata->irq < 0) {
1154 ret = bedata->irq;
1155 goto error;
1156 }
1157
1158 ret = gnttab_alloc_grant_references(1, &gref_head);
1159 if (ret < 0)
1160 goto error;
1161 ret = gnttab_claim_grant_reference(&gref_head);
1162 if (ret < 0)
1163 goto error;
1164 bedata->ref = ret;
1165 gnttab_grant_foreign_access_ref(bedata->ref, dev->otherend_id,
1166 virt_to_gfn((void *)sring), 0);
1167
1168 again:
1169 ret = xenbus_transaction_start(&xbt);
1170 if (ret) {
1171 xenbus_dev_fatal(dev, ret, "starting transaction");
1172 goto error;
1173 }
1174 ret = xenbus_printf(xbt, dev->nodename, "version", "%u", 1);
1175 if (ret)
1176 goto error_xenbus;
1177 ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", bedata->ref);
1178 if (ret)
1179 goto error_xenbus;
1180 ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
1181 evtchn);
1182 if (ret)
1183 goto error_xenbus;
1184 ret = xenbus_transaction_end(xbt, 0);
1185 if (ret) {
1186 if (ret == -EAGAIN)
1187 goto again;
1188 xenbus_dev_fatal(dev, ret, "completing transaction");
1189 goto error;
1190 }
1191 xenbus_switch_state(dev, XenbusStateInitialised);
1192
1193 return 0;
1194
1195 error_xenbus:
1196 xenbus_transaction_end(xbt, 1);
1197 xenbus_dev_fatal(dev, ret, "writing xenstore");
1198 error:
1199 pvcalls_front_remove(dev);
1200 return ret;
1201 }
1202
1203 static void pvcalls_front_changed(struct xenbus_device *dev,
1204 enum xenbus_state backend_state)
1205 {
1206 switch (backend_state) {
1207 case XenbusStateReconfiguring:
1208 case XenbusStateReconfigured:
1209 case XenbusStateInitialising:
1210 case XenbusStateInitialised:
1211 case XenbusStateUnknown:
1212 break;
1213
1214 case XenbusStateInitWait:
1215 break;
1216
1217 case XenbusStateConnected:
1218 xenbus_switch_state(dev, XenbusStateConnected);
1219 break;
1220
1221 case XenbusStateClosed:
1222 if (dev->state == XenbusStateClosed)
1223 break;
1224 /* Missed the backend's CLOSING state */
1225 /* fall through */
1226 case XenbusStateClosing:
1227 xenbus_frontend_closed(dev);
1228 break;
1229 }
1230 }
1231
1232 static struct xenbus_driver pvcalls_front_driver = {
1233 .ids = pvcalls_front_ids,
1234 .probe = pvcalls_front_probe,
1235 .remove = pvcalls_front_remove,
1236 .otherend_changed = pvcalls_front_changed,
1237 };
1238
1239 static int __init pvcalls_frontend_init(void)
1240 {
1241 if (!xen_domain())
1242 return -ENODEV;
1243
1244 pr_info("Initialising Xen pvcalls frontend driver\n");
1245
1246 return xenbus_register_frontend(&pvcalls_front_driver);
1247 }
1248
1249 module_init(pvcalls_frontend_init);
1250
1251 MODULE_DESCRIPTION("Xen PV Calls frontend driver");
1252 MODULE_AUTHOR("Stefano Stabellini <sstabellini@kernel.org>");
1253 MODULE_LICENSE("GPL");
CRIS linux kernel tree