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 #include <trace/events/sock.h> 18 19 #include <xen/events.h> 20 #include <xen/grant_table.h> 21 #include <xen/xen.h> 22 #include <xen/xenbus.h> 23 #include <xen/interface/io/pvcalls.h> 24 25 #define PVCALLS_VERSIONS "1" 26 #define MAX_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER 27 28 static struct pvcalls_back_global { 29 struct list_head frontends; 30 struct semaphore frontends_lock; 31 } pvcalls_back_global; 32 33 /* 34 * Per-frontend data structure. It contains pointers to the command 35 * ring, its event channel, a list of active sockets and a tree of 36 * passive sockets. 37 */ 38 struct pvcalls_fedata { 39 struct list_head list; 40 struct xenbus_device *dev; 41 struct xen_pvcalls_sring *sring; 42 struct xen_pvcalls_back_ring ring; 43 int irq; 44 struct list_head socket_mappings; 45 struct radix_tree_root socketpass_mappings; 46 struct semaphore socket_lock; 47 }; 48 49 struct pvcalls_ioworker { 50 struct work_struct register_work; 51 struct workqueue_struct *wq; 52 }; 53 54 struct sock_mapping { 55 struct list_head list; 56 struct pvcalls_fedata *fedata; 57 struct sockpass_mapping *sockpass; 58 struct socket *sock; 59 uint64_t id; 60 grant_ref_t ref; 61 struct pvcalls_data_intf *ring; 62 void *bytes; 63 struct pvcalls_data data; 64 uint32_t ring_order; 65 int irq; 66 atomic_t read; 67 atomic_t write; 68 atomic_t io; 69 atomic_t release; 70 atomic_t eoi; 71 void (*saved_data_ready)(struct sock *sk); 72 struct pvcalls_ioworker ioworker; 73 }; 74 75 struct sockpass_mapping { 76 struct list_head list; 77 struct pvcalls_fedata *fedata; 78 struct socket *sock; 79 uint64_t id; 80 struct xen_pvcalls_request reqcopy; 81 spinlock_t copy_lock; 82 struct workqueue_struct *wq; 83 struct work_struct register_work; 84 void (*saved_data_ready)(struct sock *sk); 85 }; 86 87 static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map); 88 static int pvcalls_back_release_active(struct xenbus_device *dev, 89 struct pvcalls_fedata *fedata, 90 struct sock_mapping *map); 91 92 static bool pvcalls_conn_back_read(void *opaque) 93 { 94 struct sock_mapping *map = (struct sock_mapping *)opaque; 95 struct msghdr msg; 96 struct kvec vec[2]; 97 RING_IDX cons, prod, size, wanted, array_size, masked_prod, masked_cons; 98 int32_t error; 99 struct pvcalls_data_intf *intf = map->ring; 100 struct pvcalls_data *data = &map->data; 101 unsigned long flags; 102 int ret; 103 104 array_size = XEN_FLEX_RING_SIZE(map->ring_order); 105 cons = intf->in_cons; 106 prod = intf->in_prod; 107 error = intf->in_error; 108 /* read the indexes first, then deal with the data */ 109 virt_mb(); 110 111 if (error) 112 return false; 113 114 size = pvcalls_queued(prod, cons, array_size); 115 if (size >= array_size) 116 return false; 117 spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags); 118 if (skb_queue_empty(&map->sock->sk->sk_receive_queue)) { 119 atomic_set(&map->read, 0); 120 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, 121 flags); 122 return true; 123 } 124 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags); 125 wanted = array_size - size; 126 masked_prod = pvcalls_mask(prod, array_size); 127 masked_cons = pvcalls_mask(cons, array_size); 128 129 memset(&msg, 0, sizeof(msg)); 130 if (masked_prod < masked_cons) { 131 vec[0].iov_base = data->in + masked_prod; 132 vec[0].iov_len = wanted; 133 iov_iter_kvec(&msg.msg_iter, ITER_DEST, vec, 1, wanted); 134 } else { 135 vec[0].iov_base = data->in + masked_prod; 136 vec[0].iov_len = array_size - masked_prod; 137 vec[1].iov_base = data->in; 138 vec[1].iov_len = wanted - vec[0].iov_len; 139 iov_iter_kvec(&msg.msg_iter, ITER_DEST, vec, 2, wanted); 140 } 141 142 atomic_set(&map->read, 0); 143 ret = inet_recvmsg(map->sock, &msg, wanted, MSG_DONTWAIT); 144 WARN_ON(ret > wanted); 145 if (ret == -EAGAIN) /* shouldn't happen */ 146 return true; 147 if (!ret) 148 ret = -ENOTCONN; 149 spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags); 150 if (ret > 0 && !skb_queue_empty(&map->sock->sk->sk_receive_queue)) 151 atomic_inc(&map->read); 152 spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags); 153 154 /* write the data, then modify the indexes */ 155 virt_wmb(); 156 if (ret < 0) { 157 atomic_set(&map->read, 0); 158 intf->in_error = ret; 159 } else 160 intf->in_prod = prod + ret; 161 /* update the indexes, then notify the other end */ 162 virt_wmb(); 163 notify_remote_via_irq(map->irq); 164 165 return true; 166 } 167 168 static bool pvcalls_conn_back_write(struct sock_mapping *map) 169 { 170 struct pvcalls_data_intf *intf = map->ring; 171 struct pvcalls_data *data = &map->data; 172 struct msghdr msg; 173 struct kvec vec[2]; 174 RING_IDX cons, prod, size, array_size; 175 int ret; 176 177 atomic_set(&map->write, 0); 178 179 cons = intf->out_cons; 180 prod = intf->out_prod; 181 /* read the indexes before dealing with the data */ 182 virt_mb(); 183 184 array_size = XEN_FLEX_RING_SIZE(map->ring_order); 185 size = pvcalls_queued(prod, cons, array_size); 186 if (size == 0) 187 return false; 188 189 memset(&msg, 0, sizeof(msg)); 190 msg.msg_flags |= MSG_DONTWAIT; 191 if (pvcalls_mask(prod, array_size) > pvcalls_mask(cons, array_size)) { 192 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size); 193 vec[0].iov_len = size; 194 iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, vec, 1, size); 195 } else { 196 vec[0].iov_base = data->out + pvcalls_mask(cons, array_size); 197 vec[0].iov_len = array_size - pvcalls_mask(cons, array_size); 198 vec[1].iov_base = data->out; 199 vec[1].iov_len = size - vec[0].iov_len; 200 iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, vec, 2, size); 201 } 202 203 ret = inet_sendmsg(map->sock, &msg, size); 204 if (ret == -EAGAIN) { 205 atomic_inc(&map->write); 206 atomic_inc(&map->io); 207 return true; 208 } 209 210 /* write the data, then update the indexes */ 211 virt_wmb(); 212 if (ret < 0) { 213 intf->out_error = ret; 214 } else { 215 intf->out_error = 0; 216 intf->out_cons = cons + ret; 217 prod = intf->out_prod; 218 } 219 /* update the indexes, then notify the other end */ 220 virt_wmb(); 221 if (prod != cons + ret) { 222 atomic_inc(&map->write); 223 atomic_inc(&map->io); 224 } 225 notify_remote_via_irq(map->irq); 226 227 return true; 228 } 229 230 static void pvcalls_back_ioworker(struct work_struct *work) 231 { 232 struct pvcalls_ioworker *ioworker = container_of(work, 233 struct pvcalls_ioworker, register_work); 234 struct sock_mapping *map = container_of(ioworker, struct sock_mapping, 235 ioworker); 236 unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS; 237 238 while (atomic_read(&map->io) > 0) { 239 if (atomic_read(&map->release) > 0) { 240 atomic_set(&map->release, 0); 241 return; 242 } 243 244 if (atomic_read(&map->read) > 0 && 245 pvcalls_conn_back_read(map)) 246 eoi_flags = 0; 247 if (atomic_read(&map->write) > 0 && 248 pvcalls_conn_back_write(map)) 249 eoi_flags = 0; 250 251 if (atomic_read(&map->eoi) > 0 && !atomic_read(&map->write)) { 252 atomic_set(&map->eoi, 0); 253 xen_irq_lateeoi(map->irq, eoi_flags); 254 eoi_flags = XEN_EOI_FLAG_SPURIOUS; 255 } 256 257 atomic_dec(&map->io); 258 } 259 } 260 261 static int pvcalls_back_socket(struct xenbus_device *dev, 262 struct xen_pvcalls_request *req) 263 { 264 struct pvcalls_fedata *fedata; 265 int ret; 266 struct xen_pvcalls_response *rsp; 267 268 fedata = dev_get_drvdata(&dev->dev); 269 270 if (req->u.socket.domain != AF_INET || 271 req->u.socket.type != SOCK_STREAM || 272 (req->u.socket.protocol != IPPROTO_IP && 273 req->u.socket.protocol != AF_INET)) 274 ret = -EAFNOSUPPORT; 275 else 276 ret = 0; 277 278 /* leave the actual socket allocation for later */ 279 280 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 281 rsp->req_id = req->req_id; 282 rsp->cmd = req->cmd; 283 rsp->u.socket.id = req->u.socket.id; 284 rsp->ret = ret; 285 286 return 0; 287 } 288 289 static void pvcalls_sk_state_change(struct sock *sock) 290 { 291 struct sock_mapping *map = sock->sk_user_data; 292 293 if (map == NULL) 294 return; 295 296 atomic_inc(&map->read); 297 notify_remote_via_irq(map->irq); 298 } 299 300 static void pvcalls_sk_data_ready(struct sock *sock) 301 { 302 struct sock_mapping *map = sock->sk_user_data; 303 struct pvcalls_ioworker *iow; 304 305 trace_sk_data_ready(sock); 306 307 if (map == NULL) 308 return; 309 310 iow = &map->ioworker; 311 atomic_inc(&map->read); 312 atomic_inc(&map->io); 313 queue_work(iow->wq, &iow->register_work); 314 } 315 316 static struct sock_mapping *pvcalls_new_active_socket( 317 struct pvcalls_fedata *fedata, 318 uint64_t id, 319 grant_ref_t ref, 320 evtchn_port_t evtchn, 321 struct socket *sock) 322 { 323 int ret; 324 struct sock_mapping *map; 325 void *page; 326 327 map = kzalloc(sizeof(*map), GFP_KERNEL); 328 if (map == NULL) 329 return NULL; 330 331 map->fedata = fedata; 332 map->sock = sock; 333 map->id = id; 334 map->ref = ref; 335 336 ret = xenbus_map_ring_valloc(fedata->dev, &ref, 1, &page); 337 if (ret < 0) 338 goto out; 339 map->ring = page; 340 map->ring_order = map->ring->ring_order; 341 /* first read the order, then map the data ring */ 342 virt_rmb(); 343 if (map->ring_order > MAX_RING_ORDER) { 344 pr_warn("%s frontend requested ring_order %u, which is > MAX (%u)\n", 345 __func__, map->ring_order, MAX_RING_ORDER); 346 goto out; 347 } 348 ret = xenbus_map_ring_valloc(fedata->dev, map->ring->ref, 349 (1 << map->ring_order), &page); 350 if (ret < 0) 351 goto out; 352 map->bytes = page; 353 354 ret = bind_interdomain_evtchn_to_irqhandler_lateeoi( 355 fedata->dev, evtchn, 356 pvcalls_back_conn_event, 0, "pvcalls-backend", map); 357 if (ret < 0) 358 goto out; 359 map->irq = ret; 360 361 map->data.in = map->bytes; 362 map->data.out = map->bytes + XEN_FLEX_RING_SIZE(map->ring_order); 363 364 map->ioworker.wq = alloc_workqueue("pvcalls_io", WQ_UNBOUND, 1); 365 if (!map->ioworker.wq) 366 goto out; 367 atomic_set(&map->io, 1); 368 INIT_WORK(&map->ioworker.register_work, pvcalls_back_ioworker); 369 370 down(&fedata->socket_lock); 371 list_add_tail(&map->list, &fedata->socket_mappings); 372 up(&fedata->socket_lock); 373 374 write_lock_bh(&map->sock->sk->sk_callback_lock); 375 map->saved_data_ready = map->sock->sk->sk_data_ready; 376 map->sock->sk->sk_user_data = map; 377 map->sock->sk->sk_data_ready = pvcalls_sk_data_ready; 378 map->sock->sk->sk_state_change = pvcalls_sk_state_change; 379 write_unlock_bh(&map->sock->sk->sk_callback_lock); 380 381 return map; 382 out: 383 down(&fedata->socket_lock); 384 list_del(&map->list); 385 pvcalls_back_release_active(fedata->dev, fedata, map); 386 up(&fedata->socket_lock); 387 return NULL; 388 } 389 390 static int pvcalls_back_connect(struct xenbus_device *dev, 391 struct xen_pvcalls_request *req) 392 { 393 struct pvcalls_fedata *fedata; 394 int ret = -EINVAL; 395 struct socket *sock; 396 struct sock_mapping *map; 397 struct xen_pvcalls_response *rsp; 398 struct sockaddr *sa = (struct sockaddr *)&req->u.connect.addr; 399 400 fedata = dev_get_drvdata(&dev->dev); 401 402 if (req->u.connect.len < sizeof(sa->sa_family) || 403 req->u.connect.len > sizeof(req->u.connect.addr) || 404 sa->sa_family != AF_INET) 405 goto out; 406 407 ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock); 408 if (ret < 0) 409 goto out; 410 ret = inet_stream_connect(sock, sa, req->u.connect.len, 0); 411 if (ret < 0) { 412 sock_release(sock); 413 goto out; 414 } 415 416 map = pvcalls_new_active_socket(fedata, 417 req->u.connect.id, 418 req->u.connect.ref, 419 req->u.connect.evtchn, 420 sock); 421 if (!map) { 422 ret = -EFAULT; 423 sock_release(sock); 424 } 425 426 out: 427 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 428 rsp->req_id = req->req_id; 429 rsp->cmd = req->cmd; 430 rsp->u.connect.id = req->u.connect.id; 431 rsp->ret = ret; 432 433 return 0; 434 } 435 436 static int pvcalls_back_release_active(struct xenbus_device *dev, 437 struct pvcalls_fedata *fedata, 438 struct sock_mapping *map) 439 { 440 disable_irq(map->irq); 441 if (map->sock->sk != NULL) { 442 write_lock_bh(&map->sock->sk->sk_callback_lock); 443 map->sock->sk->sk_user_data = NULL; 444 map->sock->sk->sk_data_ready = map->saved_data_ready; 445 write_unlock_bh(&map->sock->sk->sk_callback_lock); 446 } 447 448 atomic_set(&map->release, 1); 449 flush_work(&map->ioworker.register_work); 450 451 xenbus_unmap_ring_vfree(dev, map->bytes); 452 xenbus_unmap_ring_vfree(dev, (void *)map->ring); 453 unbind_from_irqhandler(map->irq, map); 454 455 sock_release(map->sock); 456 kfree(map); 457 458 return 0; 459 } 460 461 static int pvcalls_back_release_passive(struct xenbus_device *dev, 462 struct pvcalls_fedata *fedata, 463 struct sockpass_mapping *mappass) 464 { 465 if (mappass->sock->sk != NULL) { 466 write_lock_bh(&mappass->sock->sk->sk_callback_lock); 467 mappass->sock->sk->sk_user_data = NULL; 468 mappass->sock->sk->sk_data_ready = mappass->saved_data_ready; 469 write_unlock_bh(&mappass->sock->sk->sk_callback_lock); 470 } 471 sock_release(mappass->sock); 472 destroy_workqueue(mappass->wq); 473 kfree(mappass); 474 475 return 0; 476 } 477 478 static int pvcalls_back_release(struct xenbus_device *dev, 479 struct xen_pvcalls_request *req) 480 { 481 struct pvcalls_fedata *fedata; 482 struct sock_mapping *map, *n; 483 struct sockpass_mapping *mappass; 484 int ret = 0; 485 struct xen_pvcalls_response *rsp; 486 487 fedata = dev_get_drvdata(&dev->dev); 488 489 down(&fedata->socket_lock); 490 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) { 491 if (map->id == req->u.release.id) { 492 list_del(&map->list); 493 up(&fedata->socket_lock); 494 ret = pvcalls_back_release_active(dev, fedata, map); 495 goto out; 496 } 497 } 498 mappass = radix_tree_lookup(&fedata->socketpass_mappings, 499 req->u.release.id); 500 if (mappass != NULL) { 501 radix_tree_delete(&fedata->socketpass_mappings, mappass->id); 502 up(&fedata->socket_lock); 503 ret = pvcalls_back_release_passive(dev, fedata, mappass); 504 } else 505 up(&fedata->socket_lock); 506 507 out: 508 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 509 rsp->req_id = req->req_id; 510 rsp->u.release.id = req->u.release.id; 511 rsp->cmd = req->cmd; 512 rsp->ret = ret; 513 return 0; 514 } 515 516 static void __pvcalls_back_accept(struct work_struct *work) 517 { 518 struct sockpass_mapping *mappass = container_of( 519 work, struct sockpass_mapping, register_work); 520 struct sock_mapping *map; 521 struct pvcalls_ioworker *iow; 522 struct pvcalls_fedata *fedata; 523 struct socket *sock; 524 struct xen_pvcalls_response *rsp; 525 struct xen_pvcalls_request *req; 526 int notify; 527 int ret = -EINVAL; 528 unsigned long flags; 529 530 fedata = mappass->fedata; 531 /* 532 * __pvcalls_back_accept can race against pvcalls_back_accept. 533 * We only need to check the value of "cmd" on read. It could be 534 * done atomically, but to simplify the code on the write side, we 535 * use a spinlock. 536 */ 537 spin_lock_irqsave(&mappass->copy_lock, flags); 538 req = &mappass->reqcopy; 539 if (req->cmd != PVCALLS_ACCEPT) { 540 spin_unlock_irqrestore(&mappass->copy_lock, flags); 541 return; 542 } 543 spin_unlock_irqrestore(&mappass->copy_lock, flags); 544 545 sock = sock_alloc(); 546 if (sock == NULL) 547 goto out_error; 548 sock->type = mappass->sock->type; 549 sock->ops = mappass->sock->ops; 550 551 ret = inet_accept(mappass->sock, sock, O_NONBLOCK, true); 552 if (ret == -EAGAIN) { 553 sock_release(sock); 554 return; 555 } 556 557 map = pvcalls_new_active_socket(fedata, 558 req->u.accept.id_new, 559 req->u.accept.ref, 560 req->u.accept.evtchn, 561 sock); 562 if (!map) { 563 ret = -EFAULT; 564 sock_release(sock); 565 goto out_error; 566 } 567 568 map->sockpass = mappass; 569 iow = &map->ioworker; 570 atomic_inc(&map->read); 571 atomic_inc(&map->io); 572 queue_work(iow->wq, &iow->register_work); 573 574 out_error: 575 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 576 rsp->req_id = req->req_id; 577 rsp->cmd = req->cmd; 578 rsp->u.accept.id = req->u.accept.id; 579 rsp->ret = ret; 580 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify); 581 if (notify) 582 notify_remote_via_irq(fedata->irq); 583 584 mappass->reqcopy.cmd = 0; 585 } 586 587 static void pvcalls_pass_sk_data_ready(struct sock *sock) 588 { 589 struct sockpass_mapping *mappass = sock->sk_user_data; 590 struct pvcalls_fedata *fedata; 591 struct xen_pvcalls_response *rsp; 592 unsigned long flags; 593 int notify; 594 595 trace_sk_data_ready(sock); 596 597 if (mappass == NULL) 598 return; 599 600 fedata = mappass->fedata; 601 spin_lock_irqsave(&mappass->copy_lock, flags); 602 if (mappass->reqcopy.cmd == PVCALLS_POLL) { 603 rsp = RING_GET_RESPONSE(&fedata->ring, 604 fedata->ring.rsp_prod_pvt++); 605 rsp->req_id = mappass->reqcopy.req_id; 606 rsp->u.poll.id = mappass->reqcopy.u.poll.id; 607 rsp->cmd = mappass->reqcopy.cmd; 608 rsp->ret = 0; 609 610 mappass->reqcopy.cmd = 0; 611 spin_unlock_irqrestore(&mappass->copy_lock, flags); 612 613 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify); 614 if (notify) 615 notify_remote_via_irq(mappass->fedata->irq); 616 } else { 617 spin_unlock_irqrestore(&mappass->copy_lock, flags); 618 queue_work(mappass->wq, &mappass->register_work); 619 } 620 } 621 622 static int pvcalls_back_bind(struct xenbus_device *dev, 623 struct xen_pvcalls_request *req) 624 { 625 struct pvcalls_fedata *fedata; 626 int ret; 627 struct sockpass_mapping *map; 628 struct xen_pvcalls_response *rsp; 629 630 fedata = dev_get_drvdata(&dev->dev); 631 632 map = kzalloc(sizeof(*map), GFP_KERNEL); 633 if (map == NULL) { 634 ret = -ENOMEM; 635 goto out; 636 } 637 638 INIT_WORK(&map->register_work, __pvcalls_back_accept); 639 spin_lock_init(&map->copy_lock); 640 map->wq = alloc_workqueue("pvcalls_wq", WQ_UNBOUND, 1); 641 if (!map->wq) { 642 ret = -ENOMEM; 643 goto out; 644 } 645 646 ret = sock_create(AF_INET, SOCK_STREAM, 0, &map->sock); 647 if (ret < 0) 648 goto out; 649 650 ret = inet_bind(map->sock, (struct sockaddr *)&req->u.bind.addr, 651 req->u.bind.len); 652 if (ret < 0) 653 goto out; 654 655 map->fedata = fedata; 656 map->id = req->u.bind.id; 657 658 down(&fedata->socket_lock); 659 ret = radix_tree_insert(&fedata->socketpass_mappings, map->id, 660 map); 661 up(&fedata->socket_lock); 662 if (ret) 663 goto out; 664 665 write_lock_bh(&map->sock->sk->sk_callback_lock); 666 map->saved_data_ready = map->sock->sk->sk_data_ready; 667 map->sock->sk->sk_user_data = map; 668 map->sock->sk->sk_data_ready = pvcalls_pass_sk_data_ready; 669 write_unlock_bh(&map->sock->sk->sk_callback_lock); 670 671 out: 672 if (ret) { 673 if (map && map->sock) 674 sock_release(map->sock); 675 if (map && map->wq) 676 destroy_workqueue(map->wq); 677 kfree(map); 678 } 679 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 680 rsp->req_id = req->req_id; 681 rsp->cmd = req->cmd; 682 rsp->u.bind.id = req->u.bind.id; 683 rsp->ret = ret; 684 return 0; 685 } 686 687 static int pvcalls_back_listen(struct xenbus_device *dev, 688 struct xen_pvcalls_request *req) 689 { 690 struct pvcalls_fedata *fedata; 691 int ret = -EINVAL; 692 struct sockpass_mapping *map; 693 struct xen_pvcalls_response *rsp; 694 695 fedata = dev_get_drvdata(&dev->dev); 696 697 down(&fedata->socket_lock); 698 map = radix_tree_lookup(&fedata->socketpass_mappings, req->u.listen.id); 699 up(&fedata->socket_lock); 700 if (map == NULL) 701 goto out; 702 703 ret = inet_listen(map->sock, req->u.listen.backlog); 704 705 out: 706 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 707 rsp->req_id = req->req_id; 708 rsp->cmd = req->cmd; 709 rsp->u.listen.id = req->u.listen.id; 710 rsp->ret = ret; 711 return 0; 712 } 713 714 static int pvcalls_back_accept(struct xenbus_device *dev, 715 struct xen_pvcalls_request *req) 716 { 717 struct pvcalls_fedata *fedata; 718 struct sockpass_mapping *mappass; 719 int ret = -EINVAL; 720 struct xen_pvcalls_response *rsp; 721 unsigned long flags; 722 723 fedata = dev_get_drvdata(&dev->dev); 724 725 down(&fedata->socket_lock); 726 mappass = radix_tree_lookup(&fedata->socketpass_mappings, 727 req->u.accept.id); 728 up(&fedata->socket_lock); 729 if (mappass == NULL) 730 goto out_error; 731 732 /* 733 * Limitation of the current implementation: only support one 734 * concurrent accept or poll call on one socket. 735 */ 736 spin_lock_irqsave(&mappass->copy_lock, flags); 737 if (mappass->reqcopy.cmd != 0) { 738 spin_unlock_irqrestore(&mappass->copy_lock, flags); 739 ret = -EINTR; 740 goto out_error; 741 } 742 743 mappass->reqcopy = *req; 744 spin_unlock_irqrestore(&mappass->copy_lock, flags); 745 queue_work(mappass->wq, &mappass->register_work); 746 747 /* Tell the caller we don't need to send back a notification yet */ 748 return -1; 749 750 out_error: 751 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 752 rsp->req_id = req->req_id; 753 rsp->cmd = req->cmd; 754 rsp->u.accept.id = req->u.accept.id; 755 rsp->ret = ret; 756 return 0; 757 } 758 759 static int pvcalls_back_poll(struct xenbus_device *dev, 760 struct xen_pvcalls_request *req) 761 { 762 struct pvcalls_fedata *fedata; 763 struct sockpass_mapping *mappass; 764 struct xen_pvcalls_response *rsp; 765 struct inet_connection_sock *icsk; 766 struct request_sock_queue *queue; 767 unsigned long flags; 768 int ret; 769 bool data; 770 771 fedata = dev_get_drvdata(&dev->dev); 772 773 down(&fedata->socket_lock); 774 mappass = radix_tree_lookup(&fedata->socketpass_mappings, 775 req->u.poll.id); 776 up(&fedata->socket_lock); 777 if (mappass == NULL) 778 return -EINVAL; 779 780 /* 781 * Limitation of the current implementation: only support one 782 * concurrent accept or poll call on one socket. 783 */ 784 spin_lock_irqsave(&mappass->copy_lock, flags); 785 if (mappass->reqcopy.cmd != 0) { 786 ret = -EINTR; 787 goto out; 788 } 789 790 mappass->reqcopy = *req; 791 icsk = inet_csk(mappass->sock->sk); 792 queue = &icsk->icsk_accept_queue; 793 data = READ_ONCE(queue->rskq_accept_head) != NULL; 794 if (data) { 795 mappass->reqcopy.cmd = 0; 796 ret = 0; 797 goto out; 798 } 799 spin_unlock_irqrestore(&mappass->copy_lock, flags); 800 801 /* Tell the caller we don't need to send back a notification yet */ 802 return -1; 803 804 out: 805 spin_unlock_irqrestore(&mappass->copy_lock, flags); 806 807 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 808 rsp->req_id = req->req_id; 809 rsp->cmd = req->cmd; 810 rsp->u.poll.id = req->u.poll.id; 811 rsp->ret = ret; 812 return 0; 813 } 814 815 static int pvcalls_back_handle_cmd(struct xenbus_device *dev, 816 struct xen_pvcalls_request *req) 817 { 818 int ret = 0; 819 820 switch (req->cmd) { 821 case PVCALLS_SOCKET: 822 ret = pvcalls_back_socket(dev, req); 823 break; 824 case PVCALLS_CONNECT: 825 ret = pvcalls_back_connect(dev, req); 826 break; 827 case PVCALLS_RELEASE: 828 ret = pvcalls_back_release(dev, req); 829 break; 830 case PVCALLS_BIND: 831 ret = pvcalls_back_bind(dev, req); 832 break; 833 case PVCALLS_LISTEN: 834 ret = pvcalls_back_listen(dev, req); 835 break; 836 case PVCALLS_ACCEPT: 837 ret = pvcalls_back_accept(dev, req); 838 break; 839 case PVCALLS_POLL: 840 ret = pvcalls_back_poll(dev, req); 841 break; 842 default: 843 { 844 struct pvcalls_fedata *fedata; 845 struct xen_pvcalls_response *rsp; 846 847 fedata = dev_get_drvdata(&dev->dev); 848 rsp = RING_GET_RESPONSE( 849 &fedata->ring, fedata->ring.rsp_prod_pvt++); 850 rsp->req_id = req->req_id; 851 rsp->cmd = req->cmd; 852 rsp->ret = -ENOTSUPP; 853 break; 854 } 855 } 856 return ret; 857 } 858 859 static void pvcalls_back_work(struct pvcalls_fedata *fedata) 860 { 861 int notify, notify_all = 0, more = 1; 862 struct xen_pvcalls_request req; 863 struct xenbus_device *dev = fedata->dev; 864 865 while (more) { 866 while (RING_HAS_UNCONSUMED_REQUESTS(&fedata->ring)) { 867 RING_COPY_REQUEST(&fedata->ring, 868 fedata->ring.req_cons++, 869 &req); 870 871 if (!pvcalls_back_handle_cmd(dev, &req)) { 872 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY( 873 &fedata->ring, notify); 874 notify_all += notify; 875 } 876 } 877 878 if (notify_all) { 879 notify_remote_via_irq(fedata->irq); 880 notify_all = 0; 881 } 882 883 RING_FINAL_CHECK_FOR_REQUESTS(&fedata->ring, more); 884 } 885 } 886 887 static irqreturn_t pvcalls_back_event(int irq, void *dev_id) 888 { 889 struct xenbus_device *dev = dev_id; 890 struct pvcalls_fedata *fedata = NULL; 891 unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS; 892 893 if (dev) { 894 fedata = dev_get_drvdata(&dev->dev); 895 if (fedata) { 896 pvcalls_back_work(fedata); 897 eoi_flags = 0; 898 } 899 } 900 901 xen_irq_lateeoi(irq, eoi_flags); 902 903 return IRQ_HANDLED; 904 } 905 906 static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map) 907 { 908 struct sock_mapping *map = sock_map; 909 struct pvcalls_ioworker *iow; 910 911 if (map == NULL || map->sock == NULL || map->sock->sk == NULL || 912 map->sock->sk->sk_user_data != map) { 913 xen_irq_lateeoi(irq, 0); 914 return IRQ_HANDLED; 915 } 916 917 iow = &map->ioworker; 918 919 atomic_inc(&map->write); 920 atomic_inc(&map->eoi); 921 atomic_inc(&map->io); 922 queue_work(iow->wq, &iow->register_work); 923 924 return IRQ_HANDLED; 925 } 926 927 static int backend_connect(struct xenbus_device *dev) 928 { 929 int err; 930 evtchn_port_t evtchn; 931 grant_ref_t ring_ref; 932 struct pvcalls_fedata *fedata = NULL; 933 934 fedata = kzalloc(sizeof(struct pvcalls_fedata), GFP_KERNEL); 935 if (!fedata) 936 return -ENOMEM; 937 938 fedata->irq = -1; 939 err = xenbus_scanf(XBT_NIL, dev->otherend, "port", "%u", 940 &evtchn); 941 if (err != 1) { 942 err = -EINVAL; 943 xenbus_dev_fatal(dev, err, "reading %s/event-channel", 944 dev->otherend); 945 goto error; 946 } 947 948 err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", "%u", &ring_ref); 949 if (err != 1) { 950 err = -EINVAL; 951 xenbus_dev_fatal(dev, err, "reading %s/ring-ref", 952 dev->otherend); 953 goto error; 954 } 955 956 err = bind_interdomain_evtchn_to_irq_lateeoi(dev, evtchn); 957 if (err < 0) 958 goto error; 959 fedata->irq = err; 960 961 err = request_threaded_irq(fedata->irq, NULL, pvcalls_back_event, 962 IRQF_ONESHOT, "pvcalls-back", dev); 963 if (err < 0) 964 goto error; 965 966 err = xenbus_map_ring_valloc(dev, &ring_ref, 1, 967 (void **)&fedata->sring); 968 if (err < 0) 969 goto error; 970 971 BACK_RING_INIT(&fedata->ring, fedata->sring, XEN_PAGE_SIZE * 1); 972 fedata->dev = dev; 973 974 INIT_LIST_HEAD(&fedata->socket_mappings); 975 INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL); 976 sema_init(&fedata->socket_lock, 1); 977 dev_set_drvdata(&dev->dev, fedata); 978 979 down(&pvcalls_back_global.frontends_lock); 980 list_add_tail(&fedata->list, &pvcalls_back_global.frontends); 981 up(&pvcalls_back_global.frontends_lock); 982 983 return 0; 984 985 error: 986 if (fedata->irq >= 0) 987 unbind_from_irqhandler(fedata->irq, dev); 988 if (fedata->sring != NULL) 989 xenbus_unmap_ring_vfree(dev, fedata->sring); 990 kfree(fedata); 991 return err; 992 } 993 994 static int backend_disconnect(struct xenbus_device *dev) 995 { 996 struct pvcalls_fedata *fedata; 997 struct sock_mapping *map, *n; 998 struct sockpass_mapping *mappass; 999 struct radix_tree_iter iter; 1000 void **slot; 1001 1002 1003 fedata = dev_get_drvdata(&dev->dev); 1004 1005 down(&fedata->socket_lock); 1006 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) { 1007 list_del(&map->list); 1008 pvcalls_back_release_active(dev, fedata, map); 1009 } 1010 1011 radix_tree_for_each_slot(slot, &fedata->socketpass_mappings, &iter, 0) { 1012 mappass = radix_tree_deref_slot(slot); 1013 if (!mappass) 1014 continue; 1015 if (radix_tree_exception(mappass)) { 1016 if (radix_tree_deref_retry(mappass)) 1017 slot = radix_tree_iter_retry(&iter); 1018 } else { 1019 radix_tree_delete(&fedata->socketpass_mappings, 1020 mappass->id); 1021 pvcalls_back_release_passive(dev, fedata, mappass); 1022 } 1023 } 1024 up(&fedata->socket_lock); 1025 1026 unbind_from_irqhandler(fedata->irq, dev); 1027 xenbus_unmap_ring_vfree(dev, fedata->sring); 1028 1029 list_del(&fedata->list); 1030 kfree(fedata); 1031 dev_set_drvdata(&dev->dev, NULL); 1032 1033 return 0; 1034 } 1035 1036 static int pvcalls_back_probe(struct xenbus_device *dev, 1037 const struct xenbus_device_id *id) 1038 { 1039 int err, abort; 1040 struct xenbus_transaction xbt; 1041 1042 again: 1043 abort = 1; 1044 1045 err = xenbus_transaction_start(&xbt); 1046 if (err) { 1047 pr_warn("%s cannot create xenstore transaction\n", __func__); 1048 return err; 1049 } 1050 1051 err = xenbus_printf(xbt, dev->nodename, "versions", "%s", 1052 PVCALLS_VERSIONS); 1053 if (err) { 1054 pr_warn("%s write out 'versions' failed\n", __func__); 1055 goto abort; 1056 } 1057 1058 err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u", 1059 MAX_RING_ORDER); 1060 if (err) { 1061 pr_warn("%s write out 'max-page-order' failed\n", __func__); 1062 goto abort; 1063 } 1064 1065 err = xenbus_printf(xbt, dev->nodename, "function-calls", 1066 XENBUS_FUNCTIONS_CALLS); 1067 if (err) { 1068 pr_warn("%s write out 'function-calls' failed\n", __func__); 1069 goto abort; 1070 } 1071 1072 abort = 0; 1073 abort: 1074 err = xenbus_transaction_end(xbt, abort); 1075 if (err) { 1076 if (err == -EAGAIN && !abort) 1077 goto again; 1078 pr_warn("%s cannot complete xenstore transaction\n", __func__); 1079 return err; 1080 } 1081 1082 if (abort) 1083 return -EFAULT; 1084 1085 xenbus_switch_state(dev, XenbusStateInitWait); 1086 1087 return 0; 1088 } 1089 1090 static void set_backend_state(struct xenbus_device *dev, 1091 enum xenbus_state state) 1092 { 1093 while (dev->state != state) { 1094 switch (dev->state) { 1095 case XenbusStateClosed: 1096 switch (state) { 1097 case XenbusStateInitWait: 1098 case XenbusStateConnected: 1099 xenbus_switch_state(dev, XenbusStateInitWait); 1100 break; 1101 case XenbusStateClosing: 1102 xenbus_switch_state(dev, XenbusStateClosing); 1103 break; 1104 default: 1105 WARN_ON(1); 1106 } 1107 break; 1108 case XenbusStateInitWait: 1109 case XenbusStateInitialised: 1110 switch (state) { 1111 case XenbusStateConnected: 1112 if (backend_connect(dev)) 1113 return; 1114 xenbus_switch_state(dev, XenbusStateConnected); 1115 break; 1116 case XenbusStateClosing: 1117 case XenbusStateClosed: 1118 xenbus_switch_state(dev, XenbusStateClosing); 1119 break; 1120 default: 1121 WARN_ON(1); 1122 } 1123 break; 1124 case XenbusStateConnected: 1125 switch (state) { 1126 case XenbusStateInitWait: 1127 case XenbusStateClosing: 1128 case XenbusStateClosed: 1129 down(&pvcalls_back_global.frontends_lock); 1130 backend_disconnect(dev); 1131 up(&pvcalls_back_global.frontends_lock); 1132 xenbus_switch_state(dev, XenbusStateClosing); 1133 break; 1134 default: 1135 WARN_ON(1); 1136 } 1137 break; 1138 case XenbusStateClosing: 1139 switch (state) { 1140 case XenbusStateInitWait: 1141 case XenbusStateConnected: 1142 case XenbusStateClosed: 1143 xenbus_switch_state(dev, XenbusStateClosed); 1144 break; 1145 default: 1146 WARN_ON(1); 1147 } 1148 break; 1149 default: 1150 WARN_ON(1); 1151 } 1152 } 1153 } 1154 1155 static void pvcalls_back_changed(struct xenbus_device *dev, 1156 enum xenbus_state frontend_state) 1157 { 1158 switch (frontend_state) { 1159 case XenbusStateInitialising: 1160 set_backend_state(dev, XenbusStateInitWait); 1161 break; 1162 1163 case XenbusStateInitialised: 1164 case XenbusStateConnected: 1165 set_backend_state(dev, XenbusStateConnected); 1166 break; 1167 1168 case XenbusStateClosing: 1169 set_backend_state(dev, XenbusStateClosing); 1170 break; 1171 1172 case XenbusStateClosed: 1173 set_backend_state(dev, XenbusStateClosed); 1174 if (xenbus_dev_is_online(dev)) 1175 break; 1176 device_unregister(&dev->dev); 1177 break; 1178 case XenbusStateUnknown: 1179 set_backend_state(dev, XenbusStateClosed); 1180 device_unregister(&dev->dev); 1181 break; 1182 1183 default: 1184 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", 1185 frontend_state); 1186 break; 1187 } 1188 } 1189 1190 static void pvcalls_back_remove(struct xenbus_device *dev) 1191 { 1192 } 1193 1194 static int pvcalls_back_uevent(const struct xenbus_device *xdev, 1195 struct kobj_uevent_env *env) 1196 { 1197 return 0; 1198 } 1199 1200 static const struct xenbus_device_id pvcalls_back_ids[] = { 1201 { "pvcalls" }, 1202 { "" } 1203 }; 1204 1205 static struct xenbus_driver pvcalls_back_driver = { 1206 .ids = pvcalls_back_ids, 1207 .probe = pvcalls_back_probe, 1208 .remove = pvcalls_back_remove, 1209 .uevent = pvcalls_back_uevent, 1210 .otherend_changed = pvcalls_back_changed, 1211 }; 1212 1213 static int __init pvcalls_back_init(void) 1214 { 1215 int ret; 1216 1217 if (!xen_domain()) 1218 return -ENODEV; 1219 1220 ret = xenbus_register_backend(&pvcalls_back_driver); 1221 if (ret < 0) 1222 return ret; 1223 1224 sema_init(&pvcalls_back_global.frontends_lock, 1); 1225 INIT_LIST_HEAD(&pvcalls_back_global.frontends); 1226 return 0; 1227 } 1228 module_init(pvcalls_back_init); 1229 1230 static void __exit pvcalls_back_fin(void) 1231 { 1232 struct pvcalls_fedata *fedata, *nfedata; 1233 1234 down(&pvcalls_back_global.frontends_lock); 1235 list_for_each_entry_safe(fedata, nfedata, 1236 &pvcalls_back_global.frontends, list) { 1237 backend_disconnect(fedata->dev); 1238 } 1239 up(&pvcalls_back_global.frontends_lock); 1240 1241 xenbus_unregister_driver(&pvcalls_back_driver); 1242 } 1243 1244 module_exit(pvcalls_back_fin); 1245 1246 MODULE_DESCRIPTION("Xen PV Calls backend driver"); 1247 MODULE_AUTHOR("Stefano Stabellini <sstabellini@kernel.org>"); 1248 MODULE_LICENSE("GPL"); 1249