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