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 goto out_error; 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"); 1237