1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * (c) 2017 Stefano Stabellini <stefano@aporeto.com> 4 */ 5 6 #include <linux/inet.h> 7 #include <linux/kthread.h> 8 #include <linux/list.h> 9 #include <linux/radix-tree.h> 10 #include <linux/module.h> 11 #include <linux/semaphore.h> 12 #include <linux/wait.h> 13 #include <net/sock.h> 14 #include <net/inet_common.h> 15 #include <net/inet_connection_sock.h> 16 #include <net/request_sock.h> 17 18 #include <xen/events.h> 19 #include <xen/grant_table.h> 20 #include <xen/xen.h> 21 #include <xen/xenbus.h> 22 #include <xen/interface/io/pvcalls.h> 23 24 #define PVCALLS_VERSIONS "1" 25 #define MAX_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER 26 27 struct pvcalls_back_global { 28 struct list_head frontends; 29 struct semaphore frontends_lock; 30 } pvcalls_back_global; 31 32 /* 33 * Per-frontend data structure. It contains pointers to the command 34 * ring, its event channel, a list of active sockets and a tree of 35 * passive sockets. 36 */ 37 struct pvcalls_fedata { 38 struct list_head list; 39 struct xenbus_device *dev; 40 struct xen_pvcalls_sring *sring; 41 struct xen_pvcalls_back_ring ring; 42 int irq; 43 struct list_head socket_mappings; 44 struct radix_tree_root socketpass_mappings; 45 struct semaphore socket_lock; 46 }; 47 48 struct pvcalls_ioworker { 49 struct work_struct register_work; 50 struct workqueue_struct *wq; 51 }; 52 53 struct sock_mapping { 54 struct list_head list; 55 struct pvcalls_fedata *fedata; 56 struct sockpass_mapping *sockpass; 57 struct socket *sock; 58 uint64_t id; 59 grant_ref_t ref; 60 struct pvcalls_data_intf *ring; 61 void *bytes; 62 struct pvcalls_data data; 63 uint32_t ring_order; 64 int irq; 65 atomic_t read; 66 atomic_t write; 67 atomic_t io; 68 atomic_t release; 69 void (*saved_data_ready)(struct sock *sk); 70 struct pvcalls_ioworker ioworker; 71 }; 72 73 struct sockpass_mapping { 74 struct list_head list; 75 struct pvcalls_fedata *fedata; 76 struct socket *sock; 77 uint64_t id; 78 struct xen_pvcalls_request reqcopy; 79 spinlock_t copy_lock; 80 struct workqueue_struct *wq; 81 struct work_struct register_work; 82 void (*saved_data_ready)(struct sock *sk); 83 }; 84 85 static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map); 86 static int pvcalls_back_release_active(struct xenbus_device *dev, 87 struct pvcalls_fedata *fedata, 88 struct sock_mapping *map); 89 90 static void pvcalls_conn_back_read(void *opaque) 91 { 92 struct sock_mapping *map = (struct sock_mapping *)opaque; 93 struct msghdr msg; 94 struct kvec vec[2]; 95 RING_IDX cons, prod, size, wanted, array_size, masked_prod, masked_cons; 96 int32_t error; 97 struct pvcalls_data_intf *intf = map->ring; 98 struct pvcalls_data *data = &map->data; 99 unsigned long flags; 100 int ret; 101 102 array_size = XEN_FLEX_RING_SIZE(map->ring_order); 103 cons = intf->in_cons; 104 prod = intf->in_prod; 105 error = intf->in_error; 106 /* read the indexes first, then deal with the data */ 107 virt_mb(); 108 109 if (error) 110 return; 111 112 size = pvcalls_queued(prod, cons, array_size); 113 if (size >= array_size) 114 return; 115 spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags); 116 if (skb_queue_empty(&map->sock->sk->sk_receive_queue)) { 117 atomic_set(&map->read, 0); 118 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, 119 flags); 120 return; 121 } 122 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags); 123 wanted = array_size - size; 124 masked_prod = pvcalls_mask(prod, array_size); 125 masked_cons = pvcalls_mask(cons, array_size); 126 127 memset(&msg, 0, sizeof(msg)); 128 if (masked_prod < masked_cons) { 129 vec[0].iov_base = data->in + masked_prod; 130 vec[0].iov_len = wanted; 131 iov_iter_kvec(&msg.msg_iter, WRITE, vec, 1, wanted); 132 } else { 133 vec[0].iov_base = data->in + masked_prod; 134 vec[0].iov_len = array_size - masked_prod; 135 vec[1].iov_base = data->in; 136 vec[1].iov_len = wanted - vec[0].iov_len; 137 iov_iter_kvec(&msg.msg_iter, WRITE, vec, 2, wanted); 138 } 139 140 atomic_set(&map->read, 0); 141 ret = inet_recvmsg(map->sock, &msg, wanted, MSG_DONTWAIT); 142 WARN_ON(ret > wanted); 143 if (ret == -EAGAIN) /* shouldn't happen */ 144 return; 145 if (!ret) 146 ret = -ENOTCONN; 147 spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags); 148 if (ret > 0 && !skb_queue_empty(&map->sock->sk->sk_receive_queue)) 149 atomic_inc(&map->read); 150 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags); 151 152 /* write the data, then modify the indexes */ 153 virt_wmb(); 154 if (ret < 0) { 155 atomic_set(&map->read, 0); 156 intf->in_error = ret; 157 } else 158 intf->in_prod = prod + ret; 159 /* update the indexes, then notify the other end */ 160 virt_wmb(); 161 notify_remote_via_irq(map->irq); 162 163 return; 164 } 165 166 static void pvcalls_conn_back_write(struct sock_mapping *map) 167 { 168 struct pvcalls_data_intf *intf = map->ring; 169 struct pvcalls_data *data = &map->data; 170 struct msghdr msg; 171 struct kvec vec[2]; 172 RING_IDX cons, prod, size, array_size; 173 int ret; 174 175 cons = intf->out_cons; 176 prod = intf->out_prod; 177 /* read the indexes before dealing with the data */ 178 virt_mb(); 179 180 array_size = XEN_FLEX_RING_SIZE(map->ring_order); 181 size = pvcalls_queued(prod, cons, array_size); 182 if (size == 0) 183 return; 184 185 memset(&msg, 0, sizeof(msg)); 186 msg.msg_flags |= MSG_DONTWAIT; 187 if (pvcalls_mask(prod, array_size) > pvcalls_mask(cons, array_size)) { 188 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size); 189 vec[0].iov_len = size; 190 iov_iter_kvec(&msg.msg_iter, READ, vec, 1, size); 191 } else { 192 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size); 193 vec[0].iov_len = array_size - pvcalls_mask(cons, array_size); 194 vec[1].iov_base = data->out; 195 vec[1].iov_len = size - vec[0].iov_len; 196 iov_iter_kvec(&msg.msg_iter, READ, vec, 2, size); 197 } 198 199 atomic_set(&map->write, 0); 200 ret = inet_sendmsg(map->sock, &msg, size); 201 if (ret == -EAGAIN || (ret >= 0 && ret < size)) { 202 atomic_inc(&map->write); 203 atomic_inc(&map->io); 204 } 205 if (ret == -EAGAIN) 206 return; 207 208 /* write the data, then update the indexes */ 209 virt_wmb(); 210 if (ret < 0) { 211 intf->out_error = ret; 212 } else { 213 intf->out_error = 0; 214 intf->out_cons = cons + ret; 215 prod = intf->out_prod; 216 } 217 /* update the indexes, then notify the other end */ 218 virt_wmb(); 219 if (prod != cons + ret) 220 atomic_inc(&map->write); 221 notify_remote_via_irq(map->irq); 222 } 223 224 static void pvcalls_back_ioworker(struct work_struct *work) 225 { 226 struct pvcalls_ioworker *ioworker = container_of(work, 227 struct pvcalls_ioworker, register_work); 228 struct sock_mapping *map = container_of(ioworker, struct sock_mapping, 229 ioworker); 230 231 while (atomic_read(&map->io) > 0) { 232 if (atomic_read(&map->release) > 0) { 233 atomic_set(&map->release, 0); 234 return; 235 } 236 237 if (atomic_read(&map->read) > 0) 238 pvcalls_conn_back_read(map); 239 if (atomic_read(&map->write) > 0) 240 pvcalls_conn_back_write(map); 241 242 atomic_dec(&map->io); 243 } 244 } 245 246 static int pvcalls_back_socket(struct xenbus_device *dev, 247 struct xen_pvcalls_request *req) 248 { 249 struct pvcalls_fedata *fedata; 250 int ret; 251 struct xen_pvcalls_response *rsp; 252 253 fedata = dev_get_drvdata(&dev->dev); 254 255 if (req->u.socket.domain != AF_INET || 256 req->u.socket.type != SOCK_STREAM || 257 (req->u.socket.protocol != IPPROTO_IP && 258 req->u.socket.protocol != AF_INET)) 259 ret = -EAFNOSUPPORT; 260 else 261 ret = 0; 262 263 /* leave the actual socket allocation for later */ 264 265 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 266 rsp->req_id = req->req_id; 267 rsp->cmd = req->cmd; 268 rsp->u.socket.id = req->u.socket.id; 269 rsp->ret = ret; 270 271 return 0; 272 } 273 274 static void pvcalls_sk_state_change(struct sock *sock) 275 { 276 struct sock_mapping *map = sock->sk_user_data; 277 278 if (map == NULL) 279 return; 280 281 atomic_inc(&map->read); 282 notify_remote_via_irq(map->irq); 283 } 284 285 static void pvcalls_sk_data_ready(struct sock *sock) 286 { 287 struct sock_mapping *map = sock->sk_user_data; 288 struct pvcalls_ioworker *iow; 289 290 if (map == NULL) 291 return; 292 293 iow = &map->ioworker; 294 atomic_inc(&map->read); 295 atomic_inc(&map->io); 296 queue_work(iow->wq, &iow->register_work); 297 } 298 299 static struct sock_mapping *pvcalls_new_active_socket( 300 struct pvcalls_fedata *fedata, 301 uint64_t id, 302 grant_ref_t ref, 303 evtchn_port_t evtchn, 304 struct socket *sock) 305 { 306 int ret; 307 struct sock_mapping *map; 308 void *page; 309 310 map = kzalloc(sizeof(*map), GFP_KERNEL); 311 if (map == NULL) 312 return NULL; 313 314 map->fedata = fedata; 315 map->sock = sock; 316 map->id = id; 317 map->ref = ref; 318 319 ret = xenbus_map_ring_valloc(fedata->dev, &ref, 1, &page); 320 if (ret < 0) 321 goto out; 322 map->ring = page; 323 map->ring_order = map->ring->ring_order; 324 /* first read the order, then map the data ring */ 325 virt_rmb(); 326 if (map->ring_order > MAX_RING_ORDER) { 327 pr_warn("%s frontend requested ring_order %u, which is > MAX (%u)\n", 328 __func__, map->ring_order, MAX_RING_ORDER); 329 goto out; 330 } 331 ret = xenbus_map_ring_valloc(fedata->dev, map->ring->ref, 332 (1 << map->ring_order), &page); 333 if (ret < 0) 334 goto out; 335 map->bytes = page; 336 337 ret = bind_interdomain_evtchn_to_irqhandler(fedata->dev->otherend_id, 338 evtchn, 339 pvcalls_back_conn_event, 340 0, 341 "pvcalls-backend", 342 map); 343 if (ret < 0) 344 goto out; 345 map->irq = ret; 346 347 map->data.in = map->bytes; 348 map->data.out = map->bytes + XEN_FLEX_RING_SIZE(map->ring_order); 349 350 map->ioworker.wq = alloc_workqueue("pvcalls_io", WQ_UNBOUND, 1); 351 if (!map->ioworker.wq) 352 goto out; 353 atomic_set(&map->io, 1); 354 INIT_WORK(&map->ioworker.register_work, pvcalls_back_ioworker); 355 356 down(&fedata->socket_lock); 357 list_add_tail(&map->list, &fedata->socket_mappings); 358 up(&fedata->socket_lock); 359 360 write_lock_bh(&map->sock->sk->sk_callback_lock); 361 map->saved_data_ready = map->sock->sk->sk_data_ready; 362 map->sock->sk->sk_user_data = map; 363 map->sock->sk->sk_data_ready = pvcalls_sk_data_ready; 364 map->sock->sk->sk_state_change = pvcalls_sk_state_change; 365 write_unlock_bh(&map->sock->sk->sk_callback_lock); 366 367 return map; 368 out: 369 down(&fedata->socket_lock); 370 list_del(&map->list); 371 pvcalls_back_release_active(fedata->dev, fedata, map); 372 up(&fedata->socket_lock); 373 return NULL; 374 } 375 376 static int pvcalls_back_connect(struct xenbus_device *dev, 377 struct xen_pvcalls_request *req) 378 { 379 struct pvcalls_fedata *fedata; 380 int ret = -EINVAL; 381 struct socket *sock; 382 struct sock_mapping *map; 383 struct xen_pvcalls_response *rsp; 384 struct sockaddr *sa = (struct sockaddr *)&req->u.connect.addr; 385 386 fedata = dev_get_drvdata(&dev->dev); 387 388 if (req->u.connect.len < sizeof(sa->sa_family) || 389 req->u.connect.len > sizeof(req->u.connect.addr) || 390 sa->sa_family != AF_INET) 391 goto out; 392 393 ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock); 394 if (ret < 0) 395 goto out; 396 ret = inet_stream_connect(sock, sa, req->u.connect.len, 0); 397 if (ret < 0) { 398 sock_release(sock); 399 goto out; 400 } 401 402 map = pvcalls_new_active_socket(fedata, 403 req->u.connect.id, 404 req->u.connect.ref, 405 req->u.connect.evtchn, 406 sock); 407 if (!map) { 408 ret = -EFAULT; 409 sock_release(sock); 410 } 411 412 out: 413 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 414 rsp->req_id = req->req_id; 415 rsp->cmd = req->cmd; 416 rsp->u.connect.id = req->u.connect.id; 417 rsp->ret = ret; 418 419 return 0; 420 } 421 422 static int pvcalls_back_release_active(struct xenbus_device *dev, 423 struct pvcalls_fedata *fedata, 424 struct sock_mapping *map) 425 { 426 disable_irq(map->irq); 427 if (map->sock->sk != NULL) { 428 write_lock_bh(&map->sock->sk->sk_callback_lock); 429 map->sock->sk->sk_user_data = NULL; 430 map->sock->sk->sk_data_ready = map->saved_data_ready; 431 write_unlock_bh(&map->sock->sk->sk_callback_lock); 432 } 433 434 atomic_set(&map->release, 1); 435 flush_work(&map->ioworker.register_work); 436 437 xenbus_unmap_ring_vfree(dev, map->bytes); 438 xenbus_unmap_ring_vfree(dev, (void *)map->ring); 439 unbind_from_irqhandler(map->irq, map); 440 441 sock_release(map->sock); 442 kfree(map); 443 444 return 0; 445 } 446 447 static int pvcalls_back_release_passive(struct xenbus_device *dev, 448 struct pvcalls_fedata *fedata, 449 struct sockpass_mapping *mappass) 450 { 451 if (mappass->sock->sk != NULL) { 452 write_lock_bh(&mappass->sock->sk->sk_callback_lock); 453 mappass->sock->sk->sk_user_data = NULL; 454 mappass->sock->sk->sk_data_ready = mappass->saved_data_ready; 455 write_unlock_bh(&mappass->sock->sk->sk_callback_lock); 456 } 457 sock_release(mappass->sock); 458 flush_workqueue(mappass->wq); 459 destroy_workqueue(mappass->wq); 460 kfree(mappass); 461 462 return 0; 463 } 464 465 static int pvcalls_back_release(struct xenbus_device *dev, 466 struct xen_pvcalls_request *req) 467 { 468 struct pvcalls_fedata *fedata; 469 struct sock_mapping *map, *n; 470 struct sockpass_mapping *mappass; 471 int ret = 0; 472 struct xen_pvcalls_response *rsp; 473 474 fedata = dev_get_drvdata(&dev->dev); 475 476 down(&fedata->socket_lock); 477 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) { 478 if (map->id == req->u.release.id) { 479 list_del(&map->list); 480 up(&fedata->socket_lock); 481 ret = pvcalls_back_release_active(dev, fedata, map); 482 goto out; 483 } 484 } 485 mappass = radix_tree_lookup(&fedata->socketpass_mappings, 486 req->u.release.id); 487 if (mappass != NULL) { 488 radix_tree_delete(&fedata->socketpass_mappings, mappass->id); 489 up(&fedata->socket_lock); 490 ret = pvcalls_back_release_passive(dev, fedata, mappass); 491 } else 492 up(&fedata->socket_lock); 493 494 out: 495 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 496 rsp->req_id = req->req_id; 497 rsp->u.release.id = req->u.release.id; 498 rsp->cmd = req->cmd; 499 rsp->ret = ret; 500 return 0; 501 } 502 503 static void __pvcalls_back_accept(struct work_struct *work) 504 { 505 struct sockpass_mapping *mappass = container_of( 506 work, struct sockpass_mapping, register_work); 507 struct sock_mapping *map; 508 struct pvcalls_ioworker *iow; 509 struct pvcalls_fedata *fedata; 510 struct socket *sock; 511 struct xen_pvcalls_response *rsp; 512 struct xen_pvcalls_request *req; 513 int notify; 514 int ret = -EINVAL; 515 unsigned long flags; 516 517 fedata = mappass->fedata; 518 /* 519 * __pvcalls_back_accept can race against pvcalls_back_accept. 520 * We only need to check the value of "cmd" on read. It could be 521 * done atomically, but to simplify the code on the write side, we 522 * use a spinlock. 523 */ 524 spin_lock_irqsave(&mappass->copy_lock, flags); 525 req = &mappass->reqcopy; 526 if (req->cmd != PVCALLS_ACCEPT) { 527 spin_unlock_irqrestore(&mappass->copy_lock, flags); 528 return; 529 } 530 spin_unlock_irqrestore(&mappass->copy_lock, flags); 531 532 sock = sock_alloc(); 533 if (sock == NULL) 534 goto out_error; 535 sock->type = mappass->sock->type; 536 sock->ops = mappass->sock->ops; 537 538 ret = inet_accept(mappass->sock, sock, O_NONBLOCK, true); 539 if (ret == -EAGAIN) { 540 sock_release(sock); 541 return; 542 } 543 544 map = pvcalls_new_active_socket(fedata, 545 req->u.accept.id_new, 546 req->u.accept.ref, 547 req->u.accept.evtchn, 548 sock); 549 if (!map) { 550 ret = -EFAULT; 551 sock_release(sock); 552 goto out_error; 553 } 554 555 map->sockpass = mappass; 556 iow = &map->ioworker; 557 atomic_inc(&map->read); 558 atomic_inc(&map->io); 559 queue_work(iow->wq, &iow->register_work); 560 561 out_error: 562 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 563 rsp->req_id = req->req_id; 564 rsp->cmd = req->cmd; 565 rsp->u.accept.id = req->u.accept.id; 566 rsp->ret = ret; 567 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify); 568 if (notify) 569 notify_remote_via_irq(fedata->irq); 570 571 mappass->reqcopy.cmd = 0; 572 } 573 574 static void pvcalls_pass_sk_data_ready(struct sock *sock) 575 { 576 struct sockpass_mapping *mappass = sock->sk_user_data; 577 struct pvcalls_fedata *fedata; 578 struct xen_pvcalls_response *rsp; 579 unsigned long flags; 580 int notify; 581 582 if (mappass == NULL) 583 return; 584 585 fedata = mappass->fedata; 586 spin_lock_irqsave(&mappass->copy_lock, flags); 587 if (mappass->reqcopy.cmd == PVCALLS_POLL) { 588 rsp = RING_GET_RESPONSE(&fedata->ring, 589 fedata->ring.rsp_prod_pvt++); 590 rsp->req_id = mappass->reqcopy.req_id; 591 rsp->u.poll.id = mappass->reqcopy.u.poll.id; 592 rsp->cmd = mappass->reqcopy.cmd; 593 rsp->ret = 0; 594 595 mappass->reqcopy.cmd = 0; 596 spin_unlock_irqrestore(&mappass->copy_lock, flags); 597 598 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify); 599 if (notify) 600 notify_remote_via_irq(mappass->fedata->irq); 601 } else { 602 spin_unlock_irqrestore(&mappass->copy_lock, flags); 603 queue_work(mappass->wq, &mappass->register_work); 604 } 605 } 606 607 static int pvcalls_back_bind(struct xenbus_device *dev, 608 struct xen_pvcalls_request *req) 609 { 610 struct pvcalls_fedata *fedata; 611 int ret; 612 struct sockpass_mapping *map; 613 struct xen_pvcalls_response *rsp; 614 615 fedata = dev_get_drvdata(&dev->dev); 616 617 map = kzalloc(sizeof(*map), GFP_KERNEL); 618 if (map == NULL) { 619 ret = -ENOMEM; 620 goto out; 621 } 622 623 INIT_WORK(&map->register_work, __pvcalls_back_accept); 624 spin_lock_init(&map->copy_lock); 625 map->wq = alloc_workqueue("pvcalls_wq", WQ_UNBOUND, 1); 626 if (!map->wq) { 627 ret = -ENOMEM; 628 goto out; 629 } 630 631 ret = sock_create(AF_INET, SOCK_STREAM, 0, &map->sock); 632 if (ret < 0) 633 goto out; 634 635 ret = inet_bind(map->sock, (struct sockaddr *)&req->u.bind.addr, 636 req->u.bind.len); 637 if (ret < 0) 638 goto out; 639 640 map->fedata = fedata; 641 map->id = req->u.bind.id; 642 643 down(&fedata->socket_lock); 644 ret = radix_tree_insert(&fedata->socketpass_mappings, map->id, 645 map); 646 up(&fedata->socket_lock); 647 if (ret) 648 goto out; 649 650 write_lock_bh(&map->sock->sk->sk_callback_lock); 651 map->saved_data_ready = map->sock->sk->sk_data_ready; 652 map->sock->sk->sk_user_data = map; 653 map->sock->sk->sk_data_ready = pvcalls_pass_sk_data_ready; 654 write_unlock_bh(&map->sock->sk->sk_callback_lock); 655 656 out: 657 if (ret) { 658 if (map && map->sock) 659 sock_release(map->sock); 660 if (map && map->wq) 661 destroy_workqueue(map->wq); 662 kfree(map); 663 } 664 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 665 rsp->req_id = req->req_id; 666 rsp->cmd = req->cmd; 667 rsp->u.bind.id = req->u.bind.id; 668 rsp->ret = ret; 669 return 0; 670 } 671 672 static int pvcalls_back_listen(struct xenbus_device *dev, 673 struct xen_pvcalls_request *req) 674 { 675 struct pvcalls_fedata *fedata; 676 int ret = -EINVAL; 677 struct sockpass_mapping *map; 678 struct xen_pvcalls_response *rsp; 679 680 fedata = dev_get_drvdata(&dev->dev); 681 682 down(&fedata->socket_lock); 683 map = radix_tree_lookup(&fedata->socketpass_mappings, req->u.listen.id); 684 up(&fedata->socket_lock); 685 if (map == NULL) 686 goto out; 687 688 ret = inet_listen(map->sock, req->u.listen.backlog); 689 690 out: 691 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 692 rsp->req_id = req->req_id; 693 rsp->cmd = req->cmd; 694 rsp->u.listen.id = req->u.listen.id; 695 rsp->ret = ret; 696 return 0; 697 } 698 699 static int pvcalls_back_accept(struct xenbus_device *dev, 700 struct xen_pvcalls_request *req) 701 { 702 struct pvcalls_fedata *fedata; 703 struct sockpass_mapping *mappass; 704 int ret = -EINVAL; 705 struct xen_pvcalls_response *rsp; 706 unsigned long flags; 707 708 fedata = dev_get_drvdata(&dev->dev); 709 710 down(&fedata->socket_lock); 711 mappass = radix_tree_lookup(&fedata->socketpass_mappings, 712 req->u.accept.id); 713 up(&fedata->socket_lock); 714 if (mappass == NULL) 715 goto out_error; 716 717 /* 718 * Limitation of the current implementation: only support one 719 * concurrent accept or poll call on one socket. 720 */ 721 spin_lock_irqsave(&mappass->copy_lock, flags); 722 if (mappass->reqcopy.cmd != 0) { 723 spin_unlock_irqrestore(&mappass->copy_lock, flags); 724 ret = -EINTR; 725 goto out_error; 726 } 727 728 mappass->reqcopy = *req; 729 spin_unlock_irqrestore(&mappass->copy_lock, flags); 730 queue_work(mappass->wq, &mappass->register_work); 731 732 /* Tell the caller we don't need to send back a notification yet */ 733 return -1; 734 735 out_error: 736 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 737 rsp->req_id = req->req_id; 738 rsp->cmd = req->cmd; 739 rsp->u.accept.id = req->u.accept.id; 740 rsp->ret = ret; 741 return 0; 742 } 743 744 static int pvcalls_back_poll(struct xenbus_device *dev, 745 struct xen_pvcalls_request *req) 746 { 747 struct pvcalls_fedata *fedata; 748 struct sockpass_mapping *mappass; 749 struct xen_pvcalls_response *rsp; 750 struct inet_connection_sock *icsk; 751 struct request_sock_queue *queue; 752 unsigned long flags; 753 int ret; 754 bool data; 755 756 fedata = dev_get_drvdata(&dev->dev); 757 758 down(&fedata->socket_lock); 759 mappass = radix_tree_lookup(&fedata->socketpass_mappings, 760 req->u.poll.id); 761 up(&fedata->socket_lock); 762 if (mappass == NULL) 763 return -EINVAL; 764 765 /* 766 * Limitation of the current implementation: only support one 767 * concurrent accept or poll call on one socket. 768 */ 769 spin_lock_irqsave(&mappass->copy_lock, flags); 770 if (mappass->reqcopy.cmd != 0) { 771 ret = -EINTR; 772 goto out; 773 } 774 775 mappass->reqcopy = *req; 776 icsk = inet_csk(mappass->sock->sk); 777 queue = &icsk->icsk_accept_queue; 778 data = READ_ONCE(queue->rskq_accept_head) != NULL; 779 if (data) { 780 mappass->reqcopy.cmd = 0; 781 ret = 0; 782 goto out; 783 } 784 spin_unlock_irqrestore(&mappass->copy_lock, flags); 785 786 /* Tell the caller we don't need to send back a notification yet */ 787 return -1; 788 789 out: 790 spin_unlock_irqrestore(&mappass->copy_lock, flags); 791 792 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 793 rsp->req_id = req->req_id; 794 rsp->cmd = req->cmd; 795 rsp->u.poll.id = req->u.poll.id; 796 rsp->ret = ret; 797 return 0; 798 } 799 800 static int pvcalls_back_handle_cmd(struct xenbus_device *dev, 801 struct xen_pvcalls_request *req) 802 { 803 int ret = 0; 804 805 switch (req->cmd) { 806 case PVCALLS_SOCKET: 807 ret = pvcalls_back_socket(dev, req); 808 break; 809 case PVCALLS_CONNECT: 810 ret = pvcalls_back_connect(dev, req); 811 break; 812 case PVCALLS_RELEASE: 813 ret = pvcalls_back_release(dev, req); 814 break; 815 case PVCALLS_BIND: 816 ret = pvcalls_back_bind(dev, req); 817 break; 818 case PVCALLS_LISTEN: 819 ret = pvcalls_back_listen(dev, req); 820 break; 821 case PVCALLS_ACCEPT: 822 ret = pvcalls_back_accept(dev, req); 823 break; 824 case PVCALLS_POLL: 825 ret = pvcalls_back_poll(dev, req); 826 break; 827 default: 828 { 829 struct pvcalls_fedata *fedata; 830 struct xen_pvcalls_response *rsp; 831 832 fedata = dev_get_drvdata(&dev->dev); 833 rsp = RING_GET_RESPONSE( 834 &fedata->ring, fedata->ring.rsp_prod_pvt++); 835 rsp->req_id = req->req_id; 836 rsp->cmd = req->cmd; 837 rsp->ret = -ENOTSUPP; 838 break; 839 } 840 } 841 return ret; 842 } 843 844 static void pvcalls_back_work(struct pvcalls_fedata *fedata) 845 { 846 int notify, notify_all = 0, more = 1; 847 struct xen_pvcalls_request req; 848 struct xenbus_device *dev = fedata->dev; 849 850 while (more) { 851 while (RING_HAS_UNCONSUMED_REQUESTS(&fedata->ring)) { 852 RING_COPY_REQUEST(&fedata->ring, 853 fedata->ring.req_cons++, 854 &req); 855 856 if (!pvcalls_back_handle_cmd(dev, &req)) { 857 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY( 858 &fedata->ring, notify); 859 notify_all += notify; 860 } 861 } 862 863 if (notify_all) { 864 notify_remote_via_irq(fedata->irq); 865 notify_all = 0; 866 } 867 868 RING_FINAL_CHECK_FOR_REQUESTS(&fedata->ring, more); 869 } 870 } 871 872 static irqreturn_t pvcalls_back_event(int irq, void *dev_id) 873 { 874 struct xenbus_device *dev = dev_id; 875 struct pvcalls_fedata *fedata = NULL; 876 877 if (dev == NULL) 878 return IRQ_HANDLED; 879 880 fedata = dev_get_drvdata(&dev->dev); 881 if (fedata == NULL) 882 return IRQ_HANDLED; 883 884 pvcalls_back_work(fedata); 885 return IRQ_HANDLED; 886 } 887 888 static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map) 889 { 890 struct sock_mapping *map = sock_map; 891 struct pvcalls_ioworker *iow; 892 893 if (map == NULL || map->sock == NULL || map->sock->sk == NULL || 894 map->sock->sk->sk_user_data != map) 895 return IRQ_HANDLED; 896 897 iow = &map->ioworker; 898 899 atomic_inc(&map->write); 900 atomic_inc(&map->io); 901 queue_work(iow->wq, &iow->register_work); 902 903 return IRQ_HANDLED; 904 } 905 906 static int backend_connect(struct xenbus_device *dev) 907 { 908 int err; 909 evtchn_port_t evtchn; 910 grant_ref_t ring_ref; 911 struct pvcalls_fedata *fedata = NULL; 912 913 fedata = kzalloc(sizeof(struct pvcalls_fedata), GFP_KERNEL); 914 if (!fedata) 915 return -ENOMEM; 916 917 fedata->irq = -1; 918 err = xenbus_scanf(XBT_NIL, dev->otherend, "port", "%u", 919 &evtchn); 920 if (err != 1) { 921 err = -EINVAL; 922 xenbus_dev_fatal(dev, err, "reading %s/event-channel", 923 dev->otherend); 924 goto error; 925 } 926 927 err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", "%u", &ring_ref); 928 if (err != 1) { 929 err = -EINVAL; 930 xenbus_dev_fatal(dev, err, "reading %s/ring-ref", 931 dev->otherend); 932 goto error; 933 } 934 935 err = bind_interdomain_evtchn_to_irq(dev->otherend_id, evtchn); 936 if (err < 0) 937 goto error; 938 fedata->irq = err; 939 940 err = request_threaded_irq(fedata->irq, NULL, pvcalls_back_event, 941 IRQF_ONESHOT, "pvcalls-back", dev); 942 if (err < 0) 943 goto error; 944 945 err = xenbus_map_ring_valloc(dev, &ring_ref, 1, 946 (void **)&fedata->sring); 947 if (err < 0) 948 goto error; 949 950 BACK_RING_INIT(&fedata->ring, fedata->sring, XEN_PAGE_SIZE * 1); 951 fedata->dev = dev; 952 953 INIT_LIST_HEAD(&fedata->socket_mappings); 954 INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL); 955 sema_init(&fedata->socket_lock, 1); 956 dev_set_drvdata(&dev->dev, fedata); 957 958 down(&pvcalls_back_global.frontends_lock); 959 list_add_tail(&fedata->list, &pvcalls_back_global.frontends); 960 up(&pvcalls_back_global.frontends_lock); 961 962 return 0; 963 964 error: 965 if (fedata->irq >= 0) 966 unbind_from_irqhandler(fedata->irq, dev); 967 if (fedata->sring != NULL) 968 xenbus_unmap_ring_vfree(dev, fedata->sring); 969 kfree(fedata); 970 return err; 971 } 972 973 static int backend_disconnect(struct xenbus_device *dev) 974 { 975 struct pvcalls_fedata *fedata; 976 struct sock_mapping *map, *n; 977 struct sockpass_mapping *mappass; 978 struct radix_tree_iter iter; 979 void **slot; 980 981 982 fedata = dev_get_drvdata(&dev->dev); 983 984 down(&fedata->socket_lock); 985 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) { 986 list_del(&map->list); 987 pvcalls_back_release_active(dev, fedata, map); 988 } 989 990 radix_tree_for_each_slot(slot, &fedata->socketpass_mappings, &iter, 0) { 991 mappass = radix_tree_deref_slot(slot); 992 if (!mappass) 993 continue; 994 if (radix_tree_exception(mappass)) { 995 if (radix_tree_deref_retry(mappass)) 996 slot = radix_tree_iter_retry(&iter); 997 } else { 998 radix_tree_delete(&fedata->socketpass_mappings, 999 mappass->id); 1000 pvcalls_back_release_passive(dev, fedata, mappass); 1001 } 1002 } 1003 up(&fedata->socket_lock); 1004 1005 unbind_from_irqhandler(fedata->irq, dev); 1006 xenbus_unmap_ring_vfree(dev, fedata->sring); 1007 1008 list_del(&fedata->list); 1009 kfree(fedata); 1010 dev_set_drvdata(&dev->dev, NULL); 1011 1012 return 0; 1013 } 1014 1015 static int pvcalls_back_probe(struct xenbus_device *dev, 1016 const struct xenbus_device_id *id) 1017 { 1018 int err, abort; 1019 struct xenbus_transaction xbt; 1020 1021 again: 1022 abort = 1; 1023 1024 err = xenbus_transaction_start(&xbt); 1025 if (err) { 1026 pr_warn("%s cannot create xenstore transaction\n", __func__); 1027 return err; 1028 } 1029 1030 err = xenbus_printf(xbt, dev->nodename, "versions", "%s", 1031 PVCALLS_VERSIONS); 1032 if (err) { 1033 pr_warn("%s write out 'versions' failed\n", __func__); 1034 goto abort; 1035 } 1036 1037 err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u", 1038 MAX_RING_ORDER); 1039 if (err) { 1040 pr_warn("%s write out 'max-page-order' failed\n", __func__); 1041 goto abort; 1042 } 1043 1044 err = xenbus_printf(xbt, dev->nodename, "function-calls", 1045 XENBUS_FUNCTIONS_CALLS); 1046 if (err) { 1047 pr_warn("%s write out 'function-calls' failed\n", __func__); 1048 goto abort; 1049 } 1050 1051 abort = 0; 1052 abort: 1053 err = xenbus_transaction_end(xbt, abort); 1054 if (err) { 1055 if (err == -EAGAIN && !abort) 1056 goto again; 1057 pr_warn("%s cannot complete xenstore transaction\n", __func__); 1058 return err; 1059 } 1060 1061 if (abort) 1062 return -EFAULT; 1063 1064 xenbus_switch_state(dev, XenbusStateInitWait); 1065 1066 return 0; 1067 } 1068 1069 static void set_backend_state(struct xenbus_device *dev, 1070 enum xenbus_state state) 1071 { 1072 while (dev->state != state) { 1073 switch (dev->state) { 1074 case XenbusStateClosed: 1075 switch (state) { 1076 case XenbusStateInitWait: 1077 case XenbusStateConnected: 1078 xenbus_switch_state(dev, XenbusStateInitWait); 1079 break; 1080 case XenbusStateClosing: 1081 xenbus_switch_state(dev, XenbusStateClosing); 1082 break; 1083 default: 1084 WARN_ON(1); 1085 } 1086 break; 1087 case XenbusStateInitWait: 1088 case XenbusStateInitialised: 1089 switch (state) { 1090 case XenbusStateConnected: 1091 backend_connect(dev); 1092 xenbus_switch_state(dev, XenbusStateConnected); 1093 break; 1094 case XenbusStateClosing: 1095 case XenbusStateClosed: 1096 xenbus_switch_state(dev, XenbusStateClosing); 1097 break; 1098 default: 1099 WARN_ON(1); 1100 } 1101 break; 1102 case XenbusStateConnected: 1103 switch (state) { 1104 case XenbusStateInitWait: 1105 case XenbusStateClosing: 1106 case XenbusStateClosed: 1107 down(&pvcalls_back_global.frontends_lock); 1108 backend_disconnect(dev); 1109 up(&pvcalls_back_global.frontends_lock); 1110 xenbus_switch_state(dev, XenbusStateClosing); 1111 break; 1112 default: 1113 WARN_ON(1); 1114 } 1115 break; 1116 case XenbusStateClosing: 1117 switch (state) { 1118 case XenbusStateInitWait: 1119 case XenbusStateConnected: 1120 case XenbusStateClosed: 1121 xenbus_switch_state(dev, XenbusStateClosed); 1122 break; 1123 default: 1124 WARN_ON(1); 1125 } 1126 break; 1127 default: 1128 WARN_ON(1); 1129 } 1130 } 1131 } 1132 1133 static void pvcalls_back_changed(struct xenbus_device *dev, 1134 enum xenbus_state frontend_state) 1135 { 1136 switch (frontend_state) { 1137 case XenbusStateInitialising: 1138 set_backend_state(dev, XenbusStateInitWait); 1139 break; 1140 1141 case XenbusStateInitialised: 1142 case XenbusStateConnected: 1143 set_backend_state(dev, XenbusStateConnected); 1144 break; 1145 1146 case XenbusStateClosing: 1147 set_backend_state(dev, XenbusStateClosing); 1148 break; 1149 1150 case XenbusStateClosed: 1151 set_backend_state(dev, XenbusStateClosed); 1152 if (xenbus_dev_is_online(dev)) 1153 break; 1154 device_unregister(&dev->dev); 1155 break; 1156 case XenbusStateUnknown: 1157 set_backend_state(dev, XenbusStateClosed); 1158 device_unregister(&dev->dev); 1159 break; 1160 1161 default: 1162 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", 1163 frontend_state); 1164 break; 1165 } 1166 } 1167 1168 static int pvcalls_back_remove(struct xenbus_device *dev) 1169 { 1170 return 0; 1171 } 1172 1173 static int pvcalls_back_uevent(struct xenbus_device *xdev, 1174 struct kobj_uevent_env *env) 1175 { 1176 return 0; 1177 } 1178 1179 static const struct xenbus_device_id pvcalls_back_ids[] = { 1180 { "pvcalls" }, 1181 { "" } 1182 }; 1183 1184 static struct xenbus_driver pvcalls_back_driver = { 1185 .ids = pvcalls_back_ids, 1186 .probe = pvcalls_back_probe, 1187 .remove = pvcalls_back_remove, 1188 .uevent = pvcalls_back_uevent, 1189 .otherend_changed = pvcalls_back_changed, 1190 }; 1191 1192 static int __init pvcalls_back_init(void) 1193 { 1194 int ret; 1195 1196 if (!xen_domain()) 1197 return -ENODEV; 1198 1199 ret = xenbus_register_backend(&pvcalls_back_driver); 1200 if (ret < 0) 1201 return ret; 1202 1203 sema_init(&pvcalls_back_global.frontends_lock, 1); 1204 INIT_LIST_HEAD(&pvcalls_back_global.frontends); 1205 return 0; 1206 } 1207 module_init(pvcalls_back_init); 1208 1209 static void __exit pvcalls_back_fin(void) 1210 { 1211 struct pvcalls_fedata *fedata, *nfedata; 1212 1213 down(&pvcalls_back_global.frontends_lock); 1214 list_for_each_entry_safe(fedata, nfedata, 1215 &pvcalls_back_global.frontends, list) { 1216 backend_disconnect(fedata->dev); 1217 } 1218 up(&pvcalls_back_global.frontends_lock); 1219 1220 xenbus_unregister_driver(&pvcalls_back_driver); 1221 } 1222 1223 module_exit(pvcalls_back_fin); 1224 1225 MODULE_DESCRIPTION("Xen PV Calls backend driver"); 1226 MODULE_AUTHOR("Stefano Stabellini <sstabellini@kernel.org>"); 1227 MODULE_LICENSE("GPL"); 1228