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 msg.msg_iter.type = ITER_KVEC|WRITE; 138 msg.msg_iter.count = wanted; 139 if (masked_prod < masked_cons) { 140 vec[0].iov_base = data->in + masked_prod; 141 vec[0].iov_len = wanted; 142 msg.msg_iter.kvec = vec; 143 msg.msg_iter.nr_segs = 1; 144 } else { 145 vec[0].iov_base = data->in + masked_prod; 146 vec[0].iov_len = array_size - masked_prod; 147 vec[1].iov_base = data->in; 148 vec[1].iov_len = wanted - vec[0].iov_len; 149 msg.msg_iter.kvec = vec; 150 msg.msg_iter.nr_segs = 2; 151 } 152 153 atomic_set(&map->read, 0); 154 ret = inet_recvmsg(map->sock, &msg, wanted, MSG_DONTWAIT); 155 WARN_ON(ret > wanted); 156 if (ret == -EAGAIN) /* shouldn't happen */ 157 return; 158 if (!ret) 159 ret = -ENOTCONN; 160 spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags); 161 if (ret > 0 && !skb_queue_empty(&map->sock->sk->sk_receive_queue)) 162 atomic_inc(&map->read); 163 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags); 164 165 /* write the data, then modify the indexes */ 166 virt_wmb(); 167 if (ret < 0) 168 intf->in_error = ret; 169 else 170 intf->in_prod = prod + ret; 171 /* update the indexes, then notify the other end */ 172 virt_wmb(); 173 notify_remote_via_irq(map->irq); 174 175 return; 176 } 177 178 static void pvcalls_conn_back_write(struct sock_mapping *map) 179 { 180 struct pvcalls_data_intf *intf = map->ring; 181 struct pvcalls_data *data = &map->data; 182 struct msghdr msg; 183 struct kvec vec[2]; 184 RING_IDX cons, prod, size, array_size; 185 int ret; 186 187 cons = intf->out_cons; 188 prod = intf->out_prod; 189 /* read the indexes before dealing with the data */ 190 virt_mb(); 191 192 array_size = XEN_FLEX_RING_SIZE(map->ring_order); 193 size = pvcalls_queued(prod, cons, array_size); 194 if (size == 0) 195 return; 196 197 memset(&msg, 0, sizeof(msg)); 198 msg.msg_flags |= MSG_DONTWAIT; 199 msg.msg_iter.type = ITER_KVEC|READ; 200 msg.msg_iter.count = size; 201 if (pvcalls_mask(prod, array_size) > pvcalls_mask(cons, array_size)) { 202 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size); 203 vec[0].iov_len = size; 204 msg.msg_iter.kvec = vec; 205 msg.msg_iter.nr_segs = 1; 206 } else { 207 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size); 208 vec[0].iov_len = array_size - pvcalls_mask(cons, array_size); 209 vec[1].iov_base = data->out; 210 vec[1].iov_len = size - vec[0].iov_len; 211 msg.msg_iter.kvec = vec; 212 msg.msg_iter.nr_segs = 2; 213 } 214 215 atomic_set(&map->write, 0); 216 ret = inet_sendmsg(map->sock, &msg, size); 217 if (ret == -EAGAIN || (ret >= 0 && ret < size)) { 218 atomic_inc(&map->write); 219 atomic_inc(&map->io); 220 } 221 if (ret == -EAGAIN) 222 return; 223 224 /* write the data, then update the indexes */ 225 virt_wmb(); 226 if (ret < 0) { 227 intf->out_error = ret; 228 } else { 229 intf->out_error = 0; 230 intf->out_cons = cons + ret; 231 prod = intf->out_prod; 232 } 233 /* update the indexes, then notify the other end */ 234 virt_wmb(); 235 if (prod != cons + ret) 236 atomic_inc(&map->write); 237 notify_remote_via_irq(map->irq); 238 } 239 240 static void pvcalls_back_ioworker(struct work_struct *work) 241 { 242 struct pvcalls_ioworker *ioworker = container_of(work, 243 struct pvcalls_ioworker, register_work); 244 struct sock_mapping *map = container_of(ioworker, struct sock_mapping, 245 ioworker); 246 247 while (atomic_read(&map->io) > 0) { 248 if (atomic_read(&map->release) > 0) { 249 atomic_set(&map->release, 0); 250 return; 251 } 252 253 if (atomic_read(&map->read) > 0) 254 pvcalls_conn_back_read(map); 255 if (atomic_read(&map->write) > 0) 256 pvcalls_conn_back_write(map); 257 258 atomic_dec(&map->io); 259 } 260 } 261 262 static int pvcalls_back_socket(struct xenbus_device *dev, 263 struct xen_pvcalls_request *req) 264 { 265 struct pvcalls_fedata *fedata; 266 int ret; 267 struct xen_pvcalls_response *rsp; 268 269 fedata = dev_get_drvdata(&dev->dev); 270 271 if (req->u.socket.domain != AF_INET || 272 req->u.socket.type != SOCK_STREAM || 273 (req->u.socket.protocol != IPPROTO_IP && 274 req->u.socket.protocol != AF_INET)) 275 ret = -EAFNOSUPPORT; 276 else 277 ret = 0; 278 279 /* leave the actual socket allocation for later */ 280 281 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 282 rsp->req_id = req->req_id; 283 rsp->cmd = req->cmd; 284 rsp->u.socket.id = req->u.socket.id; 285 rsp->ret = ret; 286 287 return 0; 288 } 289 290 static void pvcalls_sk_state_change(struct sock *sock) 291 { 292 struct sock_mapping *map = sock->sk_user_data; 293 struct pvcalls_data_intf *intf; 294 295 if (map == NULL) 296 return; 297 298 intf = map->ring; 299 intf->in_error = -ENOTCONN; 300 notify_remote_via_irq(map->irq); 301 } 302 303 static void pvcalls_sk_data_ready(struct sock *sock) 304 { 305 struct sock_mapping *map = sock->sk_user_data; 306 struct pvcalls_ioworker *iow; 307 308 if (map == NULL) 309 return; 310 311 iow = &map->ioworker; 312 atomic_inc(&map->read); 313 atomic_inc(&map->io); 314 queue_work(iow->wq, &iow->register_work); 315 } 316 317 static struct sock_mapping *pvcalls_new_active_socket( 318 struct pvcalls_fedata *fedata, 319 uint64_t id, 320 grant_ref_t ref, 321 uint32_t evtchn, 322 struct socket *sock) 323 { 324 int ret; 325 struct sock_mapping *map; 326 void *page; 327 328 map = kzalloc(sizeof(*map), GFP_KERNEL); 329 if (map == NULL) 330 return NULL; 331 332 map->fedata = fedata; 333 map->sock = sock; 334 map->id = id; 335 map->ref = ref; 336 337 ret = xenbus_map_ring_valloc(fedata->dev, &ref, 1, &page); 338 if (ret < 0) 339 goto out; 340 map->ring = page; 341 map->ring_order = map->ring->ring_order; 342 /* first read the order, then map the data ring */ 343 virt_rmb(); 344 if (map->ring_order > MAX_RING_ORDER) { 345 pr_warn("%s frontend requested ring_order %u, which is > MAX (%u)\n", 346 __func__, map->ring_order, MAX_RING_ORDER); 347 goto out; 348 } 349 ret = xenbus_map_ring_valloc(fedata->dev, map->ring->ref, 350 (1 << map->ring_order), &page); 351 if (ret < 0) 352 goto out; 353 map->bytes = page; 354 355 ret = bind_interdomain_evtchn_to_irqhandler(fedata->dev->otherend_id, 356 evtchn, 357 pvcalls_back_conn_event, 358 0, 359 "pvcalls-backend", 360 map); 361 if (ret < 0) 362 goto out; 363 map->irq = ret; 364 365 map->data.in = map->bytes; 366 map->data.out = map->bytes + XEN_FLEX_RING_SIZE(map->ring_order); 367 368 map->ioworker.wq = alloc_workqueue("pvcalls_io", WQ_UNBOUND, 1); 369 if (!map->ioworker.wq) 370 goto out; 371 atomic_set(&map->io, 1); 372 INIT_WORK(&map->ioworker.register_work, pvcalls_back_ioworker); 373 374 down(&fedata->socket_lock); 375 list_add_tail(&map->list, &fedata->socket_mappings); 376 up(&fedata->socket_lock); 377 378 write_lock_bh(&map->sock->sk->sk_callback_lock); 379 map->saved_data_ready = map->sock->sk->sk_data_ready; 380 map->sock->sk->sk_user_data = map; 381 map->sock->sk->sk_data_ready = pvcalls_sk_data_ready; 382 map->sock->sk->sk_state_change = pvcalls_sk_state_change; 383 write_unlock_bh(&map->sock->sk->sk_callback_lock); 384 385 return map; 386 out: 387 down(&fedata->socket_lock); 388 list_del(&map->list); 389 pvcalls_back_release_active(fedata->dev, fedata, map); 390 up(&fedata->socket_lock); 391 return NULL; 392 } 393 394 static int pvcalls_back_connect(struct xenbus_device *dev, 395 struct xen_pvcalls_request *req) 396 { 397 struct pvcalls_fedata *fedata; 398 int ret = -EINVAL; 399 struct socket *sock; 400 struct sock_mapping *map; 401 struct xen_pvcalls_response *rsp; 402 struct sockaddr *sa = (struct sockaddr *)&req->u.connect.addr; 403 404 fedata = dev_get_drvdata(&dev->dev); 405 406 if (req->u.connect.len < sizeof(sa->sa_family) || 407 req->u.connect.len > sizeof(req->u.connect.addr) || 408 sa->sa_family != AF_INET) 409 goto out; 410 411 ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock); 412 if (ret < 0) 413 goto out; 414 ret = inet_stream_connect(sock, sa, req->u.connect.len, 0); 415 if (ret < 0) { 416 sock_release(sock); 417 goto out; 418 } 419 420 map = pvcalls_new_active_socket(fedata, 421 req->u.connect.id, 422 req->u.connect.ref, 423 req->u.connect.evtchn, 424 sock); 425 if (!map) { 426 ret = -EFAULT; 427 sock_release(map->sock); 428 } 429 430 out: 431 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 432 rsp->req_id = req->req_id; 433 rsp->cmd = req->cmd; 434 rsp->u.connect.id = req->u.connect.id; 435 rsp->ret = ret; 436 437 return 0; 438 } 439 440 static int pvcalls_back_release_active(struct xenbus_device *dev, 441 struct pvcalls_fedata *fedata, 442 struct sock_mapping *map) 443 { 444 disable_irq(map->irq); 445 if (map->sock->sk != NULL) { 446 write_lock_bh(&map->sock->sk->sk_callback_lock); 447 map->sock->sk->sk_user_data = NULL; 448 map->sock->sk->sk_data_ready = map->saved_data_ready; 449 write_unlock_bh(&map->sock->sk->sk_callback_lock); 450 } 451 452 atomic_set(&map->release, 1); 453 flush_work(&map->ioworker.register_work); 454 455 xenbus_unmap_ring_vfree(dev, map->bytes); 456 xenbus_unmap_ring_vfree(dev, (void *)map->ring); 457 unbind_from_irqhandler(map->irq, map); 458 459 sock_release(map->sock); 460 kfree(map); 461 462 return 0; 463 } 464 465 static int pvcalls_back_release_passive(struct xenbus_device *dev, 466 struct pvcalls_fedata *fedata, 467 struct sockpass_mapping *mappass) 468 { 469 if (mappass->sock->sk != NULL) { 470 write_lock_bh(&mappass->sock->sk->sk_callback_lock); 471 mappass->sock->sk->sk_user_data = NULL; 472 mappass->sock->sk->sk_data_ready = mappass->saved_data_ready; 473 write_unlock_bh(&mappass->sock->sk->sk_callback_lock); 474 } 475 sock_release(mappass->sock); 476 flush_workqueue(mappass->wq); 477 destroy_workqueue(mappass->wq); 478 kfree(mappass); 479 480 return 0; 481 } 482 483 static int pvcalls_back_release(struct xenbus_device *dev, 484 struct xen_pvcalls_request *req) 485 { 486 struct pvcalls_fedata *fedata; 487 struct sock_mapping *map, *n; 488 struct sockpass_mapping *mappass; 489 int ret = 0; 490 struct xen_pvcalls_response *rsp; 491 492 fedata = dev_get_drvdata(&dev->dev); 493 494 down(&fedata->socket_lock); 495 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) { 496 if (map->id == req->u.release.id) { 497 list_del(&map->list); 498 up(&fedata->socket_lock); 499 ret = pvcalls_back_release_active(dev, fedata, map); 500 goto out; 501 } 502 } 503 mappass = radix_tree_lookup(&fedata->socketpass_mappings, 504 req->u.release.id); 505 if (mappass != NULL) { 506 radix_tree_delete(&fedata->socketpass_mappings, mappass->id); 507 up(&fedata->socket_lock); 508 ret = pvcalls_back_release_passive(dev, fedata, mappass); 509 } else 510 up(&fedata->socket_lock); 511 512 out: 513 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 514 rsp->req_id = req->req_id; 515 rsp->u.release.id = req->u.release.id; 516 rsp->cmd = req->cmd; 517 rsp->ret = ret; 518 return 0; 519 } 520 521 static void __pvcalls_back_accept(struct work_struct *work) 522 { 523 struct sockpass_mapping *mappass = container_of( 524 work, struct sockpass_mapping, register_work); 525 struct sock_mapping *map; 526 struct pvcalls_ioworker *iow; 527 struct pvcalls_fedata *fedata; 528 struct socket *sock; 529 struct xen_pvcalls_response *rsp; 530 struct xen_pvcalls_request *req; 531 int notify; 532 int ret = -EINVAL; 533 unsigned long flags; 534 535 fedata = mappass->fedata; 536 /* 537 * __pvcalls_back_accept can race against pvcalls_back_accept. 538 * We only need to check the value of "cmd" on read. It could be 539 * done atomically, but to simplify the code on the write side, we 540 * use a spinlock. 541 */ 542 spin_lock_irqsave(&mappass->copy_lock, flags); 543 req = &mappass->reqcopy; 544 if (req->cmd != PVCALLS_ACCEPT) { 545 spin_unlock_irqrestore(&mappass->copy_lock, flags); 546 return; 547 } 548 spin_unlock_irqrestore(&mappass->copy_lock, flags); 549 550 sock = sock_alloc(); 551 if (sock == NULL) 552 goto out_error; 553 sock->type = mappass->sock->type; 554 sock->ops = mappass->sock->ops; 555 556 ret = inet_accept(mappass->sock, sock, O_NONBLOCK, true); 557 if (ret == -EAGAIN) { 558 sock_release(sock); 559 goto out_error; 560 } 561 562 map = pvcalls_new_active_socket(fedata, 563 req->u.accept.id_new, 564 req->u.accept.ref, 565 req->u.accept.evtchn, 566 sock); 567 if (!map) { 568 ret = -EFAULT; 569 sock_release(sock); 570 goto out_error; 571 } 572 573 map->sockpass = mappass; 574 iow = &map->ioworker; 575 atomic_inc(&map->read); 576 atomic_inc(&map->io); 577 queue_work(iow->wq, &iow->register_work); 578 579 out_error: 580 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 581 rsp->req_id = req->req_id; 582 rsp->cmd = req->cmd; 583 rsp->u.accept.id = req->u.accept.id; 584 rsp->ret = ret; 585 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify); 586 if (notify) 587 notify_remote_via_irq(fedata->irq); 588 589 mappass->reqcopy.cmd = 0; 590 } 591 592 static void pvcalls_pass_sk_data_ready(struct sock *sock) 593 { 594 struct sockpass_mapping *mappass = sock->sk_user_data; 595 struct pvcalls_fedata *fedata; 596 struct xen_pvcalls_response *rsp; 597 unsigned long flags; 598 int notify; 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 } 624 625 static 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_workqueue("pvcalls_wq", WQ_UNBOUND, 1); 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); 673 674 out: 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 } 689 690 static 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); 707 708 out: 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 } 716 717 static 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; 752 753 out_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 } 761 762 static 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 = 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; 806 807 out: 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 } 817 818 static 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 } 861 862 static 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 } 889 890 static irqreturn_t pvcalls_back_event(int irq, void *dev_id) 891 { 892 struct xenbus_device *dev = dev_id; 893 struct pvcalls_fedata *fedata = NULL; 894 895 if (dev == NULL) 896 return IRQ_HANDLED; 897 898 fedata = dev_get_drvdata(&dev->dev); 899 if (fedata == NULL) 900 return IRQ_HANDLED; 901 902 pvcalls_back_work(fedata); 903 return IRQ_HANDLED; 904 } 905 906 static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map) 907 { 908 struct sock_mapping *map = sock_map; 909 struct pvcalls_ioworker *iow; 910 911 if (map == NULL || map->sock == NULL || map->sock->sk == NULL || 912 map->sock->sk->sk_user_data != map) 913 return IRQ_HANDLED; 914 915 iow = &map->ioworker; 916 917 atomic_inc(&map->write); 918 atomic_inc(&map->io); 919 queue_work(iow->wq, &iow->register_work); 920 921 return IRQ_HANDLED; 922 } 923 924 static int backend_connect(struct xenbus_device *dev) 925 { 926 int err, evtchn; 927 grant_ref_t ring_ref; 928 struct pvcalls_fedata *fedata = NULL; 929 930 fedata = kzalloc(sizeof(struct pvcalls_fedata), GFP_KERNEL); 931 if (!fedata) 932 return -ENOMEM; 933 934 fedata->irq = -1; 935 err = xenbus_scanf(XBT_NIL, dev->otherend, "port", "%u", 936 &evtchn); 937 if (err != 1) { 938 err = -EINVAL; 939 xenbus_dev_fatal(dev, err, "reading %s/event-channel", 940 dev->otherend); 941 goto error; 942 } 943 944 err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", "%u", &ring_ref); 945 if (err != 1) { 946 err = -EINVAL; 947 xenbus_dev_fatal(dev, err, "reading %s/ring-ref", 948 dev->otherend); 949 goto error; 950 } 951 952 err = bind_interdomain_evtchn_to_irq(dev->otherend_id, evtchn); 953 if (err < 0) 954 goto error; 955 fedata->irq = err; 956 957 err = request_threaded_irq(fedata->irq, NULL, pvcalls_back_event, 958 IRQF_ONESHOT, "pvcalls-back", dev); 959 if (err < 0) 960 goto error; 961 962 err = xenbus_map_ring_valloc(dev, &ring_ref, 1, 963 (void **)&fedata->sring); 964 if (err < 0) 965 goto error; 966 967 BACK_RING_INIT(&fedata->ring, fedata->sring, XEN_PAGE_SIZE * 1); 968 fedata->dev = dev; 969 970 INIT_LIST_HEAD(&fedata->socket_mappings); 971 INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL); 972 sema_init(&fedata->socket_lock, 1); 973 dev_set_drvdata(&dev->dev, fedata); 974 975 down(&pvcalls_back_global.frontends_lock); 976 list_add_tail(&fedata->list, &pvcalls_back_global.frontends); 977 up(&pvcalls_back_global.frontends_lock); 978 979 return 0; 980 981 error: 982 if (fedata->irq >= 0) 983 unbind_from_irqhandler(fedata->irq, dev); 984 if (fedata->sring != NULL) 985 xenbus_unmap_ring_vfree(dev, fedata->sring); 986 kfree(fedata); 987 return err; 988 } 989 990 static int backend_disconnect(struct xenbus_device *dev) 991 { 992 struct pvcalls_fedata *fedata; 993 struct sock_mapping *map, *n; 994 struct sockpass_mapping *mappass; 995 struct radix_tree_iter iter; 996 void **slot; 997 998 999 fedata = dev_get_drvdata(&dev->dev); 1000 1001 down(&fedata->socket_lock); 1002 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) { 1003 list_del(&map->list); 1004 pvcalls_back_release_active(dev, fedata, map); 1005 } 1006 1007 radix_tree_for_each_slot(slot, &fedata->socketpass_mappings, &iter, 0) { 1008 mappass = radix_tree_deref_slot(slot); 1009 if (!mappass) 1010 continue; 1011 if (radix_tree_exception(mappass)) { 1012 if (radix_tree_deref_retry(mappass)) 1013 slot = radix_tree_iter_retry(&iter); 1014 } else { 1015 radix_tree_delete(&fedata->socketpass_mappings, 1016 mappass->id); 1017 pvcalls_back_release_passive(dev, fedata, mappass); 1018 } 1019 } 1020 up(&fedata->socket_lock); 1021 1022 unbind_from_irqhandler(fedata->irq, dev); 1023 xenbus_unmap_ring_vfree(dev, fedata->sring); 1024 1025 list_del(&fedata->list); 1026 kfree(fedata); 1027 dev_set_drvdata(&dev->dev, NULL); 1028 1029 return 0; 1030 } 1031 1032 static int pvcalls_back_probe(struct xenbus_device *dev, 1033 const struct xenbus_device_id *id) 1034 { 1035 int err, abort; 1036 struct xenbus_transaction xbt; 1037 1038 again: 1039 abort = 1; 1040 1041 err = xenbus_transaction_start(&xbt); 1042 if (err) { 1043 pr_warn("%s cannot create xenstore transaction\n", __func__); 1044 return err; 1045 } 1046 1047 err = xenbus_printf(xbt, dev->nodename, "versions", "%s", 1048 PVCALLS_VERSIONS); 1049 if (err) { 1050 pr_warn("%s write out 'versions' failed\n", __func__); 1051 goto abort; 1052 } 1053 1054 err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u", 1055 MAX_RING_ORDER); 1056 if (err) { 1057 pr_warn("%s write out 'max-page-order' failed\n", __func__); 1058 goto abort; 1059 } 1060 1061 err = xenbus_printf(xbt, dev->nodename, "function-calls", 1062 XENBUS_FUNCTIONS_CALLS); 1063 if (err) { 1064 pr_warn("%s write out 'function-calls' failed\n", __func__); 1065 goto abort; 1066 } 1067 1068 abort = 0; 1069 abort: 1070 err = xenbus_transaction_end(xbt, abort); 1071 if (err) { 1072 if (err == -EAGAIN && !abort) 1073 goto again; 1074 pr_warn("%s cannot complete xenstore transaction\n", __func__); 1075 return err; 1076 } 1077 1078 if (abort) 1079 return -EFAULT; 1080 1081 xenbus_switch_state(dev, XenbusStateInitWait); 1082 1083 return 0; 1084 } 1085 1086 static void set_backend_state(struct xenbus_device *dev, 1087 enum xenbus_state state) 1088 { 1089 while (dev->state != state) { 1090 switch (dev->state) { 1091 case XenbusStateClosed: 1092 switch (state) { 1093 case XenbusStateInitWait: 1094 case XenbusStateConnected: 1095 xenbus_switch_state(dev, XenbusStateInitWait); 1096 break; 1097 case XenbusStateClosing: 1098 xenbus_switch_state(dev, XenbusStateClosing); 1099 break; 1100 default: 1101 WARN_ON(1); 1102 } 1103 break; 1104 case XenbusStateInitWait: 1105 case XenbusStateInitialised: 1106 switch (state) { 1107 case XenbusStateConnected: 1108 backend_connect(dev); 1109 xenbus_switch_state(dev, XenbusStateConnected); 1110 break; 1111 case XenbusStateClosing: 1112 case XenbusStateClosed: 1113 xenbus_switch_state(dev, XenbusStateClosing); 1114 break; 1115 default: 1116 WARN_ON(1); 1117 } 1118 break; 1119 case XenbusStateConnected: 1120 switch (state) { 1121 case XenbusStateInitWait: 1122 case XenbusStateClosing: 1123 case XenbusStateClosed: 1124 down(&pvcalls_back_global.frontends_lock); 1125 backend_disconnect(dev); 1126 up(&pvcalls_back_global.frontends_lock); 1127 xenbus_switch_state(dev, XenbusStateClosing); 1128 break; 1129 default: 1130 WARN_ON(1); 1131 } 1132 break; 1133 case XenbusStateClosing: 1134 switch (state) { 1135 case XenbusStateInitWait: 1136 case XenbusStateConnected: 1137 case XenbusStateClosed: 1138 xenbus_switch_state(dev, XenbusStateClosed); 1139 break; 1140 default: 1141 WARN_ON(1); 1142 } 1143 break; 1144 default: 1145 WARN_ON(1); 1146 } 1147 } 1148 } 1149 1150 static void pvcalls_back_changed(struct xenbus_device *dev, 1151 enum xenbus_state frontend_state) 1152 { 1153 switch (frontend_state) { 1154 case XenbusStateInitialising: 1155 set_backend_state(dev, XenbusStateInitWait); 1156 break; 1157 1158 case XenbusStateInitialised: 1159 case XenbusStateConnected: 1160 set_backend_state(dev, XenbusStateConnected); 1161 break; 1162 1163 case XenbusStateClosing: 1164 set_backend_state(dev, XenbusStateClosing); 1165 break; 1166 1167 case XenbusStateClosed: 1168 set_backend_state(dev, XenbusStateClosed); 1169 if (xenbus_dev_is_online(dev)) 1170 break; 1171 device_unregister(&dev->dev); 1172 break; 1173 case XenbusStateUnknown: 1174 set_backend_state(dev, XenbusStateClosed); 1175 device_unregister(&dev->dev); 1176 break; 1177 1178 default: 1179 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", 1180 frontend_state); 1181 break; 1182 } 1183 } 1184 1185 static int pvcalls_back_remove(struct xenbus_device *dev) 1186 { 1187 return 0; 1188 } 1189 1190 static int pvcalls_back_uevent(struct xenbus_device *xdev, 1191 struct kobj_uevent_env *env) 1192 { 1193 return 0; 1194 } 1195 1196 static const struct xenbus_device_id pvcalls_back_ids[] = { 1197 { "pvcalls" }, 1198 { "" } 1199 }; 1200 1201 static struct xenbus_driver pvcalls_back_driver = { 1202 .ids = pvcalls_back_ids, 1203 .probe = pvcalls_back_probe, 1204 .remove = pvcalls_back_remove, 1205 .uevent = pvcalls_back_uevent, 1206 .otherend_changed = pvcalls_back_changed, 1207 }; 1208 1209 static int __init pvcalls_back_init(void) 1210 { 1211 int ret; 1212 1213 if (!xen_domain()) 1214 return -ENODEV; 1215 1216 ret = xenbus_register_backend(&pvcalls_back_driver); 1217 if (ret < 0) 1218 return ret; 1219 1220 sema_init(&pvcalls_back_global.frontends_lock, 1); 1221 INIT_LIST_HEAD(&pvcalls_back_global.frontends); 1222 return 0; 1223 } 1224 module_init(pvcalls_back_init); 1225 1226 static void __exit pvcalls_back_fin(void) 1227 { 1228 struct pvcalls_fedata *fedata, *nfedata; 1229 1230 down(&pvcalls_back_global.frontends_lock); 1231 list_for_each_entry_safe(fedata, nfedata, 1232 &pvcalls_back_global.frontends, list) { 1233 backend_disconnect(fedata->dev); 1234 } 1235 up(&pvcalls_back_global.frontends_lock); 1236 1237 xenbus_unregister_driver(&pvcalls_back_driver); 1238 } 1239 1240 module_exit(pvcalls_back_fin); 1241