Merge tag 'for-linus-4.16-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git...
[muen/linux.git] / drivers / xen / pvcalls-back.c
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/inet.h>
16 #include <linux/kthread.h>
17 #include <linux/list.h>
18 #include <linux/radix-tree.h>
19 #include <linux/module.h>
20 #include <linux/semaphore.h>
21 #include <linux/wait.h>
22 #include <net/sock.h>
23 #include <net/inet_common.h>
24 #include <net/inet_connection_sock.h>
25 #include <net/request_sock.h>
26
27 #include <xen/events.h>
28 #include <xen/grant_table.h>
29 #include <xen/xen.h>
30 #include <xen/xenbus.h>
31 #include <xen/interface/io/pvcalls.h>
32
33 #define PVCALLS_VERSIONS "1"
34 #define MAX_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER
35
36 struct pvcalls_back_global {
37         struct list_head frontends;
38         struct semaphore frontends_lock;
39 } pvcalls_back_global;
40
41 /*
42  * Per-frontend data structure. It contains pointers to the command
43  * ring, its event channel, a list of active sockets and a tree of
44  * passive sockets.
45  */
46 struct pvcalls_fedata {
47         struct list_head list;
48         struct xenbus_device *dev;
49         struct xen_pvcalls_sring *sring;
50         struct xen_pvcalls_back_ring ring;
51         int irq;
52         struct list_head socket_mappings;
53         struct radix_tree_root socketpass_mappings;
54         struct semaphore socket_lock;
55 };
56
57 struct pvcalls_ioworker {
58         struct work_struct register_work;
59         struct workqueue_struct *wq;
60 };
61
62 struct sock_mapping {
63         struct list_head list;
64         struct pvcalls_fedata *fedata;
65         struct sockpass_mapping *sockpass;
66         struct socket *sock;
67         uint64_t id;
68         grant_ref_t ref;
69         struct pvcalls_data_intf *ring;
70         void *bytes;
71         struct pvcalls_data data;
72         uint32_t ring_order;
73         int irq;
74         atomic_t read;
75         atomic_t write;
76         atomic_t io;
77         atomic_t release;
78         void (*saved_data_ready)(struct sock *sk);
79         struct pvcalls_ioworker ioworker;
80 };
81
82 struct sockpass_mapping {
83         struct list_head list;
84         struct pvcalls_fedata *fedata;
85         struct socket *sock;
86         uint64_t id;
87         struct xen_pvcalls_request reqcopy;
88         spinlock_t copy_lock;
89         struct workqueue_struct *wq;
90         struct work_struct register_work;
91         void (*saved_data_ready)(struct sock *sk);
92 };
93
94 static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map);
95 static int pvcalls_back_release_active(struct xenbus_device *dev,
96                                        struct pvcalls_fedata *fedata,
97                                        struct sock_mapping *map);
98
99 static void pvcalls_conn_back_read(void *opaque)
100 {
101         struct sock_mapping *map = (struct sock_mapping *)opaque;
102         struct msghdr msg;
103         struct kvec vec[2];
104         RING_IDX cons, prod, size, wanted, array_size, masked_prod, masked_cons;
105         int32_t error;
106         struct pvcalls_data_intf *intf = map->ring;
107         struct pvcalls_data *data = &map->data;
108         unsigned long flags;
109         int ret;
110
111         array_size = XEN_FLEX_RING_SIZE(map->ring_order);
112         cons = intf->in_cons;
113         prod = intf->in_prod;
114         error = intf->in_error;
115         /* read the indexes first, then deal with the data */
116         virt_mb();
117
118         if (error)
119                 return;
120
121         size = pvcalls_queued(prod, cons, array_size);
122         if (size >= array_size)
123                 return;
124         spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags);
125         if (skb_queue_empty(&map->sock->sk->sk_receive_queue)) {
126                 atomic_set(&map->read, 0);
127                 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock,
128                                 flags);
129                 return;
130         }
131         spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags);
132         wanted = array_size - size;
133         masked_prod = pvcalls_mask(prod, array_size);
134         masked_cons = pvcalls_mask(cons, array_size);
135
136         memset(&msg, 0, sizeof(msg));
137         if (masked_prod < masked_cons) {
138                 vec[0].iov_base = data->in + masked_prod;
139                 vec[0].iov_len = wanted;
140                 iov_iter_kvec(&msg.msg_iter, ITER_KVEC|WRITE, vec, 1, wanted);
141         } else {
142                 vec[0].iov_base = data->in + masked_prod;
143                 vec[0].iov_len = array_size - masked_prod;
144                 vec[1].iov_base = data->in;
145                 vec[1].iov_len = wanted - vec[0].iov_len;
146                 iov_iter_kvec(&msg.msg_iter, ITER_KVEC|WRITE, vec, 2, wanted);
147         }
148
149         atomic_set(&map->read, 0);
150         ret = inet_recvmsg(map->sock, &msg, wanted, MSG_DONTWAIT);
151         WARN_ON(ret > wanted);
152         if (ret == -EAGAIN) /* shouldn't happen */
153                 return;
154         if (!ret)
155                 ret = -ENOTCONN;
156         spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags);
157         if (ret > 0 && !skb_queue_empty(&map->sock->sk->sk_receive_queue))
158                 atomic_inc(&map->read);
159         spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags);
160
161         /* write the data, then modify the indexes */
162         virt_wmb();
163         if (ret < 0)
164                 intf->in_error = ret;
165         else
166                 intf->in_prod = prod + ret;
167         /* update the indexes, then notify the other end */
168         virt_wmb();
169         notify_remote_via_irq(map->irq);
170
171         return;
172 }
173
174 static void pvcalls_conn_back_write(struct sock_mapping *map)
175 {
176         struct pvcalls_data_intf *intf = map->ring;
177         struct pvcalls_data *data = &map->data;
178         struct msghdr msg;
179         struct kvec vec[2];
180         RING_IDX cons, prod, size, array_size;
181         int ret;
182
183         cons = intf->out_cons;
184         prod = intf->out_prod;
185         /* read the indexes before dealing with the data */
186         virt_mb();
187
188         array_size = XEN_FLEX_RING_SIZE(map->ring_order);
189         size = pvcalls_queued(prod, cons, array_size);
190         if (size == 0)
191                 return;
192
193         memset(&msg, 0, sizeof(msg));
194         msg.msg_flags |= MSG_DONTWAIT;
195         if (pvcalls_mask(prod, array_size) > pvcalls_mask(cons, array_size)) {
196                 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
197                 vec[0].iov_len = size;
198                 iov_iter_kvec(&msg.msg_iter, ITER_KVEC|READ, vec, 1, size);
199         } else {
200                 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
201                 vec[0].iov_len = array_size - pvcalls_mask(cons, array_size);
202                 vec[1].iov_base = data->out;
203                 vec[1].iov_len = size - vec[0].iov_len;
204                 iov_iter_kvec(&msg.msg_iter, ITER_KVEC|READ, vec, 2, size);
205         }
206
207         atomic_set(&map->write, 0);
208         ret = inet_sendmsg(map->sock, &msg, size);
209         if (ret == -EAGAIN || (ret >= 0 && ret < size)) {
210                 atomic_inc(&map->write);
211                 atomic_inc(&map->io);
212         }
213         if (ret == -EAGAIN)
214                 return;
215
216         /* write the data, then update the indexes */
217         virt_wmb();
218         if (ret < 0) {
219                 intf->out_error = ret;
220         } else {
221                 intf->out_error = 0;
222                 intf->out_cons = cons + ret;
223                 prod = intf->out_prod;
224         }
225         /* update the indexes, then notify the other end */
226         virt_wmb();
227         if (prod != cons + ret)
228                 atomic_inc(&map->write);
229         notify_remote_via_irq(map->irq);
230 }
231
232 static void pvcalls_back_ioworker(struct work_struct *work)
233 {
234         struct pvcalls_ioworker *ioworker = container_of(work,
235                 struct pvcalls_ioworker, register_work);
236         struct sock_mapping *map = container_of(ioworker, struct sock_mapping,
237                 ioworker);
238
239         while (atomic_read(&map->io) > 0) {
240                 if (atomic_read(&map->release) > 0) {
241                         atomic_set(&map->release, 0);
242                         return;
243                 }
244
245                 if (atomic_read(&map->read) > 0)
246                         pvcalls_conn_back_read(map);
247                 if (atomic_read(&map->write) > 0)
248                         pvcalls_conn_back_write(map);
249
250                 atomic_dec(&map->io);
251         }
252 }
253
254 static int pvcalls_back_socket(struct xenbus_device *dev,
255                 struct xen_pvcalls_request *req)
256 {
257         struct pvcalls_fedata *fedata;
258         int ret;
259         struct xen_pvcalls_response *rsp;
260
261         fedata = dev_get_drvdata(&dev->dev);
262
263         if (req->u.socket.domain != AF_INET ||
264             req->u.socket.type != SOCK_STREAM ||
265             (req->u.socket.protocol != IPPROTO_IP &&
266              req->u.socket.protocol != AF_INET))
267                 ret = -EAFNOSUPPORT;
268         else
269                 ret = 0;
270
271         /* leave the actual socket allocation for later */
272
273         rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
274         rsp->req_id = req->req_id;
275         rsp->cmd = req->cmd;
276         rsp->u.socket.id = req->u.socket.id;
277         rsp->ret = ret;
278
279         return 0;
280 }
281
282 static void pvcalls_sk_state_change(struct sock *sock)
283 {
284         struct sock_mapping *map = sock->sk_user_data;
285         struct pvcalls_data_intf *intf;
286
287         if (map == NULL)
288                 return;
289
290         intf = map->ring;
291         intf->in_error = -ENOTCONN;
292         notify_remote_via_irq(map->irq);
293 }
294
295 static void pvcalls_sk_data_ready(struct sock *sock)
296 {
297         struct sock_mapping *map = sock->sk_user_data;
298         struct pvcalls_ioworker *iow;
299
300         if (map == NULL)
301                 return;
302
303         iow = &map->ioworker;
304         atomic_inc(&map->read);
305         atomic_inc(&map->io);
306         queue_work(iow->wq, &iow->register_work);
307 }
308
309 static struct sock_mapping *pvcalls_new_active_socket(
310                 struct pvcalls_fedata *fedata,
311                 uint64_t id,
312                 grant_ref_t ref,
313                 uint32_t evtchn,
314                 struct socket *sock)
315 {
316         int ret;
317         struct sock_mapping *map;
318         void *page;
319
320         map = kzalloc(sizeof(*map), GFP_KERNEL);
321         if (map == NULL)
322                 return NULL;
323
324         map->fedata = fedata;
325         map->sock = sock;
326         map->id = id;
327         map->ref = ref;
328
329         ret = xenbus_map_ring_valloc(fedata->dev, &ref, 1, &page);
330         if (ret < 0)
331                 goto out;
332         map->ring = page;
333         map->ring_order = map->ring->ring_order;
334         /* first read the order, then map the data ring */
335         virt_rmb();
336         if (map->ring_order > MAX_RING_ORDER) {
337                 pr_warn("%s frontend requested ring_order %u, which is > MAX (%u)\n",
338                                 __func__, map->ring_order, MAX_RING_ORDER);
339                 goto out;
340         }
341         ret = xenbus_map_ring_valloc(fedata->dev, map->ring->ref,
342                                      (1 << map->ring_order), &page);
343         if (ret < 0)
344                 goto out;
345         map->bytes = page;
346
347         ret = bind_interdomain_evtchn_to_irqhandler(fedata->dev->otherend_id,
348                                                     evtchn,
349                                                     pvcalls_back_conn_event,
350                                                     0,
351                                                     "pvcalls-backend",
352                                                     map);
353         if (ret < 0)
354                 goto out;
355         map->irq = ret;
356
357         map->data.in = map->bytes;
358         map->data.out = map->bytes + XEN_FLEX_RING_SIZE(map->ring_order);
359
360         map->ioworker.wq = alloc_workqueue("pvcalls_io", WQ_UNBOUND, 1);
361         if (!map->ioworker.wq)
362                 goto out;
363         atomic_set(&map->io, 1);
364         INIT_WORK(&map->ioworker.register_work, pvcalls_back_ioworker);
365
366         down(&fedata->socket_lock);
367         list_add_tail(&map->list, &fedata->socket_mappings);
368         up(&fedata->socket_lock);
369
370         write_lock_bh(&map->sock->sk->sk_callback_lock);
371         map->saved_data_ready = map->sock->sk->sk_data_ready;
372         map->sock->sk->sk_user_data = map;
373         map->sock->sk->sk_data_ready = pvcalls_sk_data_ready;
374         map->sock->sk->sk_state_change = pvcalls_sk_state_change;
375         write_unlock_bh(&map->sock->sk->sk_callback_lock);
376
377         return map;
378 out:
379         down(&fedata->socket_lock);
380         list_del(&map->list);
381         pvcalls_back_release_active(fedata->dev, fedata, map);
382         up(&fedata->socket_lock);
383         return NULL;
384 }
385
386 static int pvcalls_back_connect(struct xenbus_device *dev,
387                                 struct xen_pvcalls_request *req)
388 {
389         struct pvcalls_fedata *fedata;
390         int ret = -EINVAL;
391         struct socket *sock;
392         struct sock_mapping *map;
393         struct xen_pvcalls_response *rsp;
394         struct sockaddr *sa = (struct sockaddr *)&req->u.connect.addr;
395
396         fedata = dev_get_drvdata(&dev->dev);
397
398         if (req->u.connect.len < sizeof(sa->sa_family) ||
399             req->u.connect.len > sizeof(req->u.connect.addr) ||
400             sa->sa_family != AF_INET)
401                 goto out;
402
403         ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock);
404         if (ret < 0)
405                 goto out;
406         ret = inet_stream_connect(sock, sa, req->u.connect.len, 0);
407         if (ret < 0) {
408                 sock_release(sock);
409                 goto out;
410         }
411
412         map = pvcalls_new_active_socket(fedata,
413                                         req->u.connect.id,
414                                         req->u.connect.ref,
415                                         req->u.connect.evtchn,
416                                         sock);
417         if (!map) {
418                 ret = -EFAULT;
419                 sock_release(map->sock);
420         }
421
422 out:
423         rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
424         rsp->req_id = req->req_id;
425         rsp->cmd = req->cmd;
426         rsp->u.connect.id = req->u.connect.id;
427         rsp->ret = ret;
428
429         return 0;
430 }
431
432 static int pvcalls_back_release_active(struct xenbus_device *dev,
433                                        struct pvcalls_fedata *fedata,
434                                        struct sock_mapping *map)
435 {
436         disable_irq(map->irq);
437         if (map->sock->sk != NULL) {
438                 write_lock_bh(&map->sock->sk->sk_callback_lock);
439                 map->sock->sk->sk_user_data = NULL;
440                 map->sock->sk->sk_data_ready = map->saved_data_ready;
441                 write_unlock_bh(&map->sock->sk->sk_callback_lock);
442         }
443
444         atomic_set(&map->release, 1);
445         flush_work(&map->ioworker.register_work);
446
447         xenbus_unmap_ring_vfree(dev, map->bytes);
448         xenbus_unmap_ring_vfree(dev, (void *)map->ring);
449         unbind_from_irqhandler(map->irq, map);
450
451         sock_release(map->sock);
452         kfree(map);
453
454         return 0;
455 }
456
457 static int pvcalls_back_release_passive(struct xenbus_device *dev,
458                                         struct pvcalls_fedata *fedata,
459                                         struct sockpass_mapping *mappass)
460 {
461         if (mappass->sock->sk != NULL) {
462                 write_lock_bh(&mappass->sock->sk->sk_callback_lock);
463                 mappass->sock->sk->sk_user_data = NULL;
464                 mappass->sock->sk->sk_data_ready = mappass->saved_data_ready;
465                 write_unlock_bh(&mappass->sock->sk->sk_callback_lock);
466         }
467         sock_release(mappass->sock);
468         flush_workqueue(mappass->wq);
469         destroy_workqueue(mappass->wq);
470         kfree(mappass);
471
472         return 0;
473 }
474
475 static int pvcalls_back_release(struct xenbus_device *dev,
476                                 struct xen_pvcalls_request *req)
477 {
478         struct pvcalls_fedata *fedata;
479         struct sock_mapping *map, *n;
480         struct sockpass_mapping *mappass;
481         int ret = 0;
482         struct xen_pvcalls_response *rsp;
483
484         fedata = dev_get_drvdata(&dev->dev);
485
486         down(&fedata->socket_lock);
487         list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {
488                 if (map->id == req->u.release.id) {
489                         list_del(&map->list);
490                         up(&fedata->socket_lock);
491                         ret = pvcalls_back_release_active(dev, fedata, map);
492                         goto out;
493                 }
494         }
495         mappass = radix_tree_lookup(&fedata->socketpass_mappings,
496                                     req->u.release.id);
497         if (mappass != NULL) {
498                 radix_tree_delete(&fedata->socketpass_mappings, mappass->id);
499                 up(&fedata->socket_lock);
500                 ret = pvcalls_back_release_passive(dev, fedata, mappass);
501         } else
502                 up(&fedata->socket_lock);
503
504 out:
505         rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
506         rsp->req_id = req->req_id;
507         rsp->u.release.id = req->u.release.id;
508         rsp->cmd = req->cmd;
509         rsp->ret = ret;
510         return 0;
511 }
512
513 static void __pvcalls_back_accept(struct work_struct *work)
514 {
515         struct sockpass_mapping *mappass = container_of(
516                 work, struct sockpass_mapping, register_work);
517         struct sock_mapping *map;
518         struct pvcalls_ioworker *iow;
519         struct pvcalls_fedata *fedata;
520         struct socket *sock;
521         struct xen_pvcalls_response *rsp;
522         struct xen_pvcalls_request *req;
523         int notify;
524         int ret = -EINVAL;
525         unsigned long flags;
526
527         fedata = mappass->fedata;
528         /*
529          * __pvcalls_back_accept can race against pvcalls_back_accept.
530          * We only need to check the value of "cmd" on read. It could be
531          * done atomically, but to simplify the code on the write side, we
532          * use a spinlock.
533          */
534         spin_lock_irqsave(&mappass->copy_lock, flags);
535         req = &mappass->reqcopy;
536         if (req->cmd != PVCALLS_ACCEPT) {
537                 spin_unlock_irqrestore(&mappass->copy_lock, flags);
538                 return;
539         }
540         spin_unlock_irqrestore(&mappass->copy_lock, flags);
541
542         sock = sock_alloc();
543         if (sock == NULL)
544                 goto out_error;
545         sock->type = mappass->sock->type;
546         sock->ops = mappass->sock->ops;
547
548         ret = inet_accept(mappass->sock, sock, O_NONBLOCK, true);
549         if (ret == -EAGAIN) {
550                 sock_release(sock);
551                 return;
552         }
553
554         map = pvcalls_new_active_socket(fedata,
555                                         req->u.accept.id_new,
556                                         req->u.accept.ref,
557                                         req->u.accept.evtchn,
558                                         sock);
559         if (!map) {
560                 ret = -EFAULT;
561                 sock_release(sock);
562                 goto out_error;
563         }
564
565         map->sockpass = mappass;
566         iow = &map->ioworker;
567         atomic_inc(&map->read);
568         atomic_inc(&map->io);
569         queue_work(iow->wq, &iow->register_work);
570
571 out_error:
572         rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
573         rsp->req_id = req->req_id;
574         rsp->cmd = req->cmd;
575         rsp->u.accept.id = req->u.accept.id;
576         rsp->ret = ret;
577         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);
578         if (notify)
579                 notify_remote_via_irq(fedata->irq);
580
581         mappass->reqcopy.cmd = 0;
582 }
583
584 static void pvcalls_pass_sk_data_ready(struct sock *sock)
585 {
586         struct sockpass_mapping *mappass = sock->sk_user_data;
587         struct pvcalls_fedata *fedata;
588         struct xen_pvcalls_response *rsp;
589         unsigned long flags;
590         int notify;
591
592         if (mappass == NULL)
593                 return;
594
595         fedata = mappass->fedata;
596         spin_lock_irqsave(&mappass->copy_lock, flags);
597         if (mappass->reqcopy.cmd == PVCALLS_POLL) {
598                 rsp = RING_GET_RESPONSE(&fedata->ring,
599                                         fedata->ring.rsp_prod_pvt++);
600                 rsp->req_id = mappass->reqcopy.req_id;
601                 rsp->u.poll.id = mappass->reqcopy.u.poll.id;
602                 rsp->cmd = mappass->reqcopy.cmd;
603                 rsp->ret = 0;
604
605                 mappass->reqcopy.cmd = 0;
606                 spin_unlock_irqrestore(&mappass->copy_lock, flags);
607
608                 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify);
609                 if (notify)
610                         notify_remote_via_irq(mappass->fedata->irq);
611         } else {
612                 spin_unlock_irqrestore(&mappass->copy_lock, flags);
613                 queue_work(mappass->wq, &mappass->register_work);
614         }
615 }
616
617 static int pvcalls_back_bind(struct xenbus_device *dev,
618                              struct xen_pvcalls_request *req)
619 {
620         struct pvcalls_fedata *fedata;
621         int ret;
622         struct sockpass_mapping *map;
623         struct xen_pvcalls_response *rsp;
624
625         fedata = dev_get_drvdata(&dev->dev);
626
627         map = kzalloc(sizeof(*map), GFP_KERNEL);
628         if (map == NULL) {
629                 ret = -ENOMEM;
630                 goto out;
631         }
632
633         INIT_WORK(&map->register_work, __pvcalls_back_accept);
634         spin_lock_init(&map->copy_lock);
635         map->wq = alloc_workqueue("pvcalls_wq", WQ_UNBOUND, 1);
636         if (!map->wq) {
637                 ret = -ENOMEM;
638                 goto out;
639         }
640
641         ret = sock_create(AF_INET, SOCK_STREAM, 0, &map->sock);
642         if (ret < 0)
643                 goto out;
644
645         ret = inet_bind(map->sock, (struct sockaddr *)&req->u.bind.addr,
646                         req->u.bind.len);
647         if (ret < 0)
648                 goto out;
649
650         map->fedata = fedata;
651         map->id = req->u.bind.id;
652
653         down(&fedata->socket_lock);
654         ret = radix_tree_insert(&fedata->socketpass_mappings, map->id,
655                                 map);
656         up(&fedata->socket_lock);
657         if (ret)
658                 goto out;
659
660         write_lock_bh(&map->sock->sk->sk_callback_lock);
661         map->saved_data_ready = map->sock->sk->sk_data_ready;
662         map->sock->sk->sk_user_data = map;
663         map->sock->sk->sk_data_ready = pvcalls_pass_sk_data_ready;
664         write_unlock_bh(&map->sock->sk->sk_callback_lock);
665
666 out:
667         if (ret) {
668                 if (map && map->sock)
669                         sock_release(map->sock);
670                 if (map && map->wq)
671                         destroy_workqueue(map->wq);
672                 kfree(map);
673         }
674         rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
675         rsp->req_id = req->req_id;
676         rsp->cmd = req->cmd;
677         rsp->u.bind.id = req->u.bind.id;
678         rsp->ret = ret;
679         return 0;
680 }
681
682 static int pvcalls_back_listen(struct xenbus_device *dev,
683                                struct xen_pvcalls_request *req)
684 {
685         struct pvcalls_fedata *fedata;
686         int ret = -EINVAL;
687         struct sockpass_mapping *map;
688         struct xen_pvcalls_response *rsp;
689
690         fedata = dev_get_drvdata(&dev->dev);
691
692         down(&fedata->socket_lock);
693         map = radix_tree_lookup(&fedata->socketpass_mappings, req->u.listen.id);
694         up(&fedata->socket_lock);
695         if (map == NULL)
696                 goto out;
697
698         ret = inet_listen(map->sock, req->u.listen.backlog);
699
700 out:
701         rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
702         rsp->req_id = req->req_id;
703         rsp->cmd = req->cmd;
704         rsp->u.listen.id = req->u.listen.id;
705         rsp->ret = ret;
706         return 0;
707 }
708
709 static int pvcalls_back_accept(struct xenbus_device *dev,
710                                struct xen_pvcalls_request *req)
711 {
712         struct pvcalls_fedata *fedata;
713         struct sockpass_mapping *mappass;
714         int ret = -EINVAL;
715         struct xen_pvcalls_response *rsp;
716         unsigned long flags;
717
718         fedata = dev_get_drvdata(&dev->dev);
719
720         down(&fedata->socket_lock);
721         mappass = radix_tree_lookup(&fedata->socketpass_mappings,
722                 req->u.accept.id);
723         up(&fedata->socket_lock);
724         if (mappass == NULL)
725                 goto out_error;
726
727         /*
728          * Limitation of the current implementation: only support one
729          * concurrent accept or poll call on one socket.
730          */
731         spin_lock_irqsave(&mappass->copy_lock, flags);
732         if (mappass->reqcopy.cmd != 0) {
733                 spin_unlock_irqrestore(&mappass->copy_lock, flags);
734                 ret = -EINTR;
735                 goto out_error;
736         }
737
738         mappass->reqcopy = *req;
739         spin_unlock_irqrestore(&mappass->copy_lock, flags);
740         queue_work(mappass->wq, &mappass->register_work);
741
742         /* Tell the caller we don't need to send back a notification yet */
743         return -1;
744
745 out_error:
746         rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
747         rsp->req_id = req->req_id;
748         rsp->cmd = req->cmd;
749         rsp->u.accept.id = req->u.accept.id;
750         rsp->ret = ret;
751         return 0;
752 }
753
754 static int pvcalls_back_poll(struct xenbus_device *dev,
755                              struct xen_pvcalls_request *req)
756 {
757         struct pvcalls_fedata *fedata;
758         struct sockpass_mapping *mappass;
759         struct xen_pvcalls_response *rsp;
760         struct inet_connection_sock *icsk;
761         struct request_sock_queue *queue;
762         unsigned long flags;
763         int ret;
764         bool data;
765
766         fedata = dev_get_drvdata(&dev->dev);
767
768         down(&fedata->socket_lock);
769         mappass = radix_tree_lookup(&fedata->socketpass_mappings,
770                                     req->u.poll.id);
771         up(&fedata->socket_lock);
772         if (mappass == NULL)
773                 return -EINVAL;
774
775         /*
776          * Limitation of the current implementation: only support one
777          * concurrent accept or poll call on one socket.
778          */
779         spin_lock_irqsave(&mappass->copy_lock, flags);
780         if (mappass->reqcopy.cmd != 0) {
781                 ret = -EINTR;
782                 goto out;
783         }
784
785         mappass->reqcopy = *req;
786         icsk = inet_csk(mappass->sock->sk);
787         queue = &icsk->icsk_accept_queue;
788         data = queue->rskq_accept_head != NULL;
789         if (data) {
790                 mappass->reqcopy.cmd = 0;
791                 ret = 0;
792                 goto out;
793         }
794         spin_unlock_irqrestore(&mappass->copy_lock, flags);
795
796         /* Tell the caller we don't need to send back a notification yet */
797         return -1;
798
799 out:
800         spin_unlock_irqrestore(&mappass->copy_lock, flags);
801
802         rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
803         rsp->req_id = req->req_id;
804         rsp->cmd = req->cmd;
805         rsp->u.poll.id = req->u.poll.id;
806         rsp->ret = ret;
807         return 0;
808 }
809
810 static int pvcalls_back_handle_cmd(struct xenbus_device *dev,
811                                    struct xen_pvcalls_request *req)
812 {
813         int ret = 0;
814
815         switch (req->cmd) {
816         case PVCALLS_SOCKET:
817                 ret = pvcalls_back_socket(dev, req);
818                 break;
819         case PVCALLS_CONNECT:
820                 ret = pvcalls_back_connect(dev, req);
821                 break;
822         case PVCALLS_RELEASE:
823                 ret = pvcalls_back_release(dev, req);
824                 break;
825         case PVCALLS_BIND:
826                 ret = pvcalls_back_bind(dev, req);
827                 break;
828         case PVCALLS_LISTEN:
829                 ret = pvcalls_back_listen(dev, req);
830                 break;
831         case PVCALLS_ACCEPT:
832                 ret = pvcalls_back_accept(dev, req);
833                 break;
834         case PVCALLS_POLL:
835                 ret = pvcalls_back_poll(dev, req);
836                 break;
837         default:
838         {
839                 struct pvcalls_fedata *fedata;
840                 struct xen_pvcalls_response *rsp;
841
842                 fedata = dev_get_drvdata(&dev->dev);
843                 rsp = RING_GET_RESPONSE(
844                                 &fedata->ring, fedata->ring.rsp_prod_pvt++);
845                 rsp->req_id = req->req_id;
846                 rsp->cmd = req->cmd;
847                 rsp->ret = -ENOTSUPP;
848                 break;
849         }
850         }
851         return ret;
852 }
853
854 static void pvcalls_back_work(struct pvcalls_fedata *fedata)
855 {
856         int notify, notify_all = 0, more = 1;
857         struct xen_pvcalls_request req;
858         struct xenbus_device *dev = fedata->dev;
859
860         while (more) {
861                 while (RING_HAS_UNCONSUMED_REQUESTS(&fedata->ring)) {
862                         RING_COPY_REQUEST(&fedata->ring,
863                                           fedata->ring.req_cons++,
864                                           &req);
865
866                         if (!pvcalls_back_handle_cmd(dev, &req)) {
867                                 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(
868                                         &fedata->ring, notify);
869                                 notify_all += notify;
870                         }
871                 }
872
873                 if (notify_all) {
874                         notify_remote_via_irq(fedata->irq);
875                         notify_all = 0;
876                 }
877
878                 RING_FINAL_CHECK_FOR_REQUESTS(&fedata->ring, more);
879         }
880 }
881
882 static irqreturn_t pvcalls_back_event(int irq, void *dev_id)
883 {
884         struct xenbus_device *dev = dev_id;
885         struct pvcalls_fedata *fedata = NULL;
886
887         if (dev == NULL)
888                 return IRQ_HANDLED;
889
890         fedata = dev_get_drvdata(&dev->dev);
891         if (fedata == NULL)
892                 return IRQ_HANDLED;
893
894         pvcalls_back_work(fedata);
895         return IRQ_HANDLED;
896 }
897
898 static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map)
899 {
900         struct sock_mapping *map = sock_map;
901         struct pvcalls_ioworker *iow;
902
903         if (map == NULL || map->sock == NULL || map->sock->sk == NULL ||
904                 map->sock->sk->sk_user_data != map)
905                 return IRQ_HANDLED;
906
907         iow = &map->ioworker;
908
909         atomic_inc(&map->write);
910         atomic_inc(&map->io);
911         queue_work(iow->wq, &iow->register_work);
912
913         return IRQ_HANDLED;
914 }
915
916 static int backend_connect(struct xenbus_device *dev)
917 {
918         int err, evtchn;
919         grant_ref_t ring_ref;
920         struct pvcalls_fedata *fedata = NULL;
921
922         fedata = kzalloc(sizeof(struct pvcalls_fedata), GFP_KERNEL);
923         if (!fedata)
924                 return -ENOMEM;
925
926         fedata->irq = -1;
927         err = xenbus_scanf(XBT_NIL, dev->otherend, "port", "%u",
928                            &evtchn);
929         if (err != 1) {
930                 err = -EINVAL;
931                 xenbus_dev_fatal(dev, err, "reading %s/event-channel",
932                                  dev->otherend);
933                 goto error;
934         }
935
936         err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", "%u", &ring_ref);
937         if (err != 1) {
938                 err = -EINVAL;
939                 xenbus_dev_fatal(dev, err, "reading %s/ring-ref",
940                                  dev->otherend);
941                 goto error;
942         }
943
944         err = bind_interdomain_evtchn_to_irq(dev->otherend_id, evtchn);
945         if (err < 0)
946                 goto error;
947         fedata->irq = err;
948
949         err = request_threaded_irq(fedata->irq, NULL, pvcalls_back_event,
950                                    IRQF_ONESHOT, "pvcalls-back", dev);
951         if (err < 0)
952                 goto error;
953
954         err = xenbus_map_ring_valloc(dev, &ring_ref, 1,
955                                      (void **)&fedata->sring);
956         if (err < 0)
957                 goto error;
958
959         BACK_RING_INIT(&fedata->ring, fedata->sring, XEN_PAGE_SIZE * 1);
960         fedata->dev = dev;
961
962         INIT_LIST_HEAD(&fedata->socket_mappings);
963         INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL);
964         sema_init(&fedata->socket_lock, 1);
965         dev_set_drvdata(&dev->dev, fedata);
966
967         down(&pvcalls_back_global.frontends_lock);
968         list_add_tail(&fedata->list, &pvcalls_back_global.frontends);
969         up(&pvcalls_back_global.frontends_lock);
970
971         return 0;
972
973  error:
974         if (fedata->irq >= 0)
975                 unbind_from_irqhandler(fedata->irq, dev);
976         if (fedata->sring != NULL)
977                 xenbus_unmap_ring_vfree(dev, fedata->sring);
978         kfree(fedata);
979         return err;
980 }
981
982 static int backend_disconnect(struct xenbus_device *dev)
983 {
984         struct pvcalls_fedata *fedata;
985         struct sock_mapping *map, *n;
986         struct sockpass_mapping *mappass;
987         struct radix_tree_iter iter;
988         void **slot;
989
990
991         fedata = dev_get_drvdata(&dev->dev);
992
993         down(&fedata->socket_lock);
994         list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) {
995                 list_del(&map->list);
996                 pvcalls_back_release_active(dev, fedata, map);
997         }
998
999         radix_tree_for_each_slot(slot, &fedata->socketpass_mappings, &iter, 0) {
1000                 mappass = radix_tree_deref_slot(slot);
1001                 if (!mappass)
1002                         continue;
1003                 if (radix_tree_exception(mappass)) {
1004                         if (radix_tree_deref_retry(mappass))
1005                                 slot = radix_tree_iter_retry(&iter);
1006                 } else {
1007                         radix_tree_delete(&fedata->socketpass_mappings,
1008                                           mappass->id);
1009                         pvcalls_back_release_passive(dev, fedata, mappass);
1010                 }
1011         }
1012         up(&fedata->socket_lock);
1013
1014         unbind_from_irqhandler(fedata->irq, dev);
1015         xenbus_unmap_ring_vfree(dev, fedata->sring);
1016
1017         list_del(&fedata->list);
1018         kfree(fedata);
1019         dev_set_drvdata(&dev->dev, NULL);
1020
1021         return 0;
1022 }
1023
1024 static int pvcalls_back_probe(struct xenbus_device *dev,
1025                               const struct xenbus_device_id *id)
1026 {
1027         int err, abort;
1028         struct xenbus_transaction xbt;
1029
1030 again:
1031         abort = 1;
1032
1033         err = xenbus_transaction_start(&xbt);
1034         if (err) {
1035                 pr_warn("%s cannot create xenstore transaction\n", __func__);
1036                 return err;
1037         }
1038
1039         err = xenbus_printf(xbt, dev->nodename, "versions", "%s",
1040                             PVCALLS_VERSIONS);
1041         if (err) {
1042                 pr_warn("%s write out 'versions' failed\n", __func__);
1043                 goto abort;
1044         }
1045
1046         err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u",
1047                             MAX_RING_ORDER);
1048         if (err) {
1049                 pr_warn("%s write out 'max-page-order' failed\n", __func__);
1050                 goto abort;
1051         }
1052
1053         err = xenbus_printf(xbt, dev->nodename, "function-calls",
1054                             XENBUS_FUNCTIONS_CALLS);
1055         if (err) {
1056                 pr_warn("%s write out 'function-calls' failed\n", __func__);
1057                 goto abort;
1058         }
1059
1060         abort = 0;
1061 abort:
1062         err = xenbus_transaction_end(xbt, abort);
1063         if (err) {
1064                 if (err == -EAGAIN && !abort)
1065                         goto again;
1066                 pr_warn("%s cannot complete xenstore transaction\n", __func__);
1067                 return err;
1068         }
1069
1070         if (abort)
1071                 return -EFAULT;
1072
1073         xenbus_switch_state(dev, XenbusStateInitWait);
1074
1075         return 0;
1076 }
1077
1078 static void set_backend_state(struct xenbus_device *dev,
1079                               enum xenbus_state state)
1080 {
1081         while (dev->state != state) {
1082                 switch (dev->state) {
1083                 case XenbusStateClosed:
1084                         switch (state) {
1085                         case XenbusStateInitWait:
1086                         case XenbusStateConnected:
1087                                 xenbus_switch_state(dev, XenbusStateInitWait);
1088                                 break;
1089                         case XenbusStateClosing:
1090                                 xenbus_switch_state(dev, XenbusStateClosing);
1091                                 break;
1092                         default:
1093                                 WARN_ON(1);
1094                         }
1095                         break;
1096                 case XenbusStateInitWait:
1097                 case XenbusStateInitialised:
1098                         switch (state) {
1099                         case XenbusStateConnected:
1100                                 backend_connect(dev);
1101                                 xenbus_switch_state(dev, XenbusStateConnected);
1102                                 break;
1103                         case XenbusStateClosing:
1104                         case XenbusStateClosed:
1105                                 xenbus_switch_state(dev, XenbusStateClosing);
1106                                 break;
1107                         default:
1108                                 WARN_ON(1);
1109                         }
1110                         break;
1111                 case XenbusStateConnected:
1112                         switch (state) {
1113                         case XenbusStateInitWait:
1114                         case XenbusStateClosing:
1115                         case XenbusStateClosed:
1116                                 down(&pvcalls_back_global.frontends_lock);
1117                                 backend_disconnect(dev);
1118                                 up(&pvcalls_back_global.frontends_lock);
1119                                 xenbus_switch_state(dev, XenbusStateClosing);
1120                                 break;
1121                         default:
1122                                 WARN_ON(1);
1123                         }
1124                         break;
1125                 case XenbusStateClosing:
1126                         switch (state) {
1127                         case XenbusStateInitWait:
1128                         case XenbusStateConnected:
1129                         case XenbusStateClosed:
1130                                 xenbus_switch_state(dev, XenbusStateClosed);
1131                                 break;
1132                         default:
1133                                 WARN_ON(1);
1134                         }
1135                         break;
1136                 default:
1137                         WARN_ON(1);
1138                 }
1139         }
1140 }
1141
1142 static void pvcalls_back_changed(struct xenbus_device *dev,
1143                                  enum xenbus_state frontend_state)
1144 {
1145         switch (frontend_state) {
1146         case XenbusStateInitialising:
1147                 set_backend_state(dev, XenbusStateInitWait);
1148                 break;
1149
1150         case XenbusStateInitialised:
1151         case XenbusStateConnected:
1152                 set_backend_state(dev, XenbusStateConnected);
1153                 break;
1154
1155         case XenbusStateClosing:
1156                 set_backend_state(dev, XenbusStateClosing);
1157                 break;
1158
1159         case XenbusStateClosed:
1160                 set_backend_state(dev, XenbusStateClosed);
1161                 if (xenbus_dev_is_online(dev))
1162                         break;
1163                 device_unregister(&dev->dev);
1164                 break;
1165         case XenbusStateUnknown:
1166                 set_backend_state(dev, XenbusStateClosed);
1167                 device_unregister(&dev->dev);
1168                 break;
1169
1170         default:
1171                 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1172                                  frontend_state);
1173                 break;
1174         }
1175 }
1176
1177 static int pvcalls_back_remove(struct xenbus_device *dev)
1178 {
1179         return 0;
1180 }
1181
1182 static int pvcalls_back_uevent(struct xenbus_device *xdev,
1183                                struct kobj_uevent_env *env)
1184 {
1185         return 0;
1186 }
1187
1188 static const struct xenbus_device_id pvcalls_back_ids[] = {
1189         { "pvcalls" },
1190         { "" }
1191 };
1192
1193 static struct xenbus_driver pvcalls_back_driver = {
1194         .ids = pvcalls_back_ids,
1195         .probe = pvcalls_back_probe,
1196         .remove = pvcalls_back_remove,
1197         .uevent = pvcalls_back_uevent,
1198         .otherend_changed = pvcalls_back_changed,
1199 };
1200
1201 static int __init pvcalls_back_init(void)
1202 {
1203         int ret;
1204
1205         if (!xen_domain())
1206                 return -ENODEV;
1207
1208         ret = xenbus_register_backend(&pvcalls_back_driver);
1209         if (ret < 0)
1210                 return ret;
1211
1212         sema_init(&pvcalls_back_global.frontends_lock, 1);
1213         INIT_LIST_HEAD(&pvcalls_back_global.frontends);
1214         return 0;
1215 }
1216 module_init(pvcalls_back_init);
1217
1218 static void __exit pvcalls_back_fin(void)
1219 {
1220         struct pvcalls_fedata *fedata, *nfedata;
1221
1222         down(&pvcalls_back_global.frontends_lock);
1223         list_for_each_entry_safe(fedata, nfedata,
1224                                  &pvcalls_back_global.frontends, list) {
1225                 backend_disconnect(fedata->dev);
1226         }
1227         up(&pvcalls_back_global.frontends_lock);
1228
1229         xenbus_unregister_driver(&pvcalls_back_driver);
1230 }
1231
1232 module_exit(pvcalls_back_fin);
1233
1234 MODULE_DESCRIPTION("Xen PV Calls backend driver");
1235 MODULE_AUTHOR("Stefano Stabellini <sstabellini@kernel.org>");
1236 MODULE_LICENSE("GPL");