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 sock_release(sock); 330 return NULL; 331 } 332 333 map->fedata = fedata; 334 map->sock = sock; 335 map->id = id; 336 map->ref = ref; 337 338 ret = xenbus_map_ring_valloc(fedata->dev, &ref, 1, &page); 339 if (ret < 0) 340 goto out; 341 map->ring = page; 342 map->ring_order = map->ring->ring_order; 343 /* first read the order, then map the data ring */ 344 virt_rmb(); 345 if (map->ring_order > MAX_RING_ORDER) { 346 pr_warn("%s frontend requested ring_order %u, which is > MAX (%u)\n", 347 __func__, map->ring_order, MAX_RING_ORDER); 348 goto out; 349 } 350 ret = xenbus_map_ring_valloc(fedata->dev, map->ring->ref, 351 (1 << map->ring_order), &page); 352 if (ret < 0) 353 goto out; 354 map->bytes = page; 355 356 ret = bind_interdomain_evtchn_to_irqhandler_lateeoi( 357 fedata->dev, evtchn, 358 pvcalls_back_conn_event, 0, "pvcalls-backend", map); 359 if (ret < 0) 360 goto out; 361 map->irq = ret; 362 363 map->data.in = map->bytes; 364 map->data.out = map->bytes + XEN_FLEX_RING_SIZE(map->ring_order); 365 366 map->ioworker.wq = alloc_ordered_workqueue("pvcalls_io", 0); 367 if (!map->ioworker.wq) 368 goto out; 369 atomic_set(&map->io, 1); 370 INIT_WORK(&map->ioworker.register_work, pvcalls_back_ioworker); 371 372 down(&fedata->socket_lock); 373 list_add_tail(&map->list, &fedata->socket_mappings); 374 up(&fedata->socket_lock); 375 376 write_lock_bh(&map->sock->sk->sk_callback_lock); 377 map->saved_data_ready = map->sock->sk->sk_data_ready; 378 map->sock->sk->sk_user_data = map; 379 map->sock->sk->sk_data_ready = pvcalls_sk_data_ready; 380 map->sock->sk->sk_state_change = pvcalls_sk_state_change; 381 write_unlock_bh(&map->sock->sk->sk_callback_lock); 382 383 return map; 384 out: 385 down(&fedata->socket_lock); 386 list_del(&map->list); 387 pvcalls_back_release_active(fedata->dev, fedata, map); 388 up(&fedata->socket_lock); 389 return NULL; 390 } 391 392 static int pvcalls_back_connect(struct xenbus_device *dev, 393 struct xen_pvcalls_request *req) 394 { 395 struct pvcalls_fedata *fedata; 396 int ret = -EINVAL; 397 struct socket *sock; 398 struct sock_mapping *map; 399 struct xen_pvcalls_response *rsp; 400 struct sockaddr *sa = (struct sockaddr *)&req->u.connect.addr; 401 402 fedata = dev_get_drvdata(&dev->dev); 403 404 if (req->u.connect.len < sizeof(sa->sa_family) || 405 req->u.connect.len > sizeof(req->u.connect.addr) || 406 sa->sa_family != AF_INET) 407 goto out; 408 409 ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock); 410 if (ret < 0) 411 goto out; 412 ret = inet_stream_connect(sock, sa, req->u.connect.len, 0); 413 if (ret < 0) { 414 sock_release(sock); 415 goto out; 416 } 417 418 map = pvcalls_new_active_socket(fedata, 419 req->u.connect.id, 420 req->u.connect.ref, 421 req->u.connect.evtchn, 422 sock); 423 if (!map) 424 ret = -EFAULT; 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 proto_accept_arg arg = { 521 .flags = O_NONBLOCK, 522 .kern = true, 523 }; 524 struct sock_mapping *map; 525 struct pvcalls_ioworker *iow; 526 struct pvcalls_fedata *fedata; 527 struct socket *sock; 528 struct xen_pvcalls_response *rsp; 529 struct xen_pvcalls_request *req; 530 int notify; 531 int ret = -EINVAL; 532 unsigned long flags; 533 534 fedata = mappass->fedata; 535 /* 536 * __pvcalls_back_accept can race against pvcalls_back_accept. 537 * We only need to check the value of "cmd" on read. It could be 538 * done atomically, but to simplify the code on the write side, we 539 * use a spinlock. 540 */ 541 spin_lock_irqsave(&mappass->copy_lock, flags); 542 req = &mappass->reqcopy; 543 if (req->cmd != PVCALLS_ACCEPT) { 544 spin_unlock_irqrestore(&mappass->copy_lock, flags); 545 return; 546 } 547 spin_unlock_irqrestore(&mappass->copy_lock, flags); 548 549 sock = sock_alloc(); 550 if (sock == NULL) 551 goto out_error; 552 sock->type = mappass->sock->type; 553 sock->ops = mappass->sock->ops; 554 555 ret = inet_accept(mappass->sock, sock, &arg); 556 if (ret == -EAGAIN) { 557 sock_release(sock); 558 return; 559 } 560 561 map = pvcalls_new_active_socket(fedata, 562 req->u.accept.id_new, 563 req->u.accept.ref, 564 req->u.accept.evtchn, 565 sock); 566 if (!map) { 567 ret = -EFAULT; 568 goto out_error; 569 } 570 571 map->sockpass = mappass; 572 iow = &map->ioworker; 573 atomic_inc(&map->read); 574 atomic_inc(&map->io); 575 queue_work(iow->wq, &iow->register_work); 576 577 out_error: 578 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 579 rsp->req_id = req->req_id; 580 rsp->cmd = req->cmd; 581 rsp->u.accept.id = req->u.accept.id; 582 rsp->ret = ret; 583 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify); 584 if (notify) 585 notify_remote_via_irq(fedata->irq); 586 587 mappass->reqcopy.cmd = 0; 588 } 589 590 static void pvcalls_pass_sk_data_ready(struct sock *sock) 591 { 592 struct sockpass_mapping *mappass = sock->sk_user_data; 593 struct pvcalls_fedata *fedata; 594 struct xen_pvcalls_response *rsp; 595 unsigned long flags; 596 int notify; 597 598 trace_sk_data_ready(sock); 599 600 if (mappass == NULL) 601 return; 602 603 fedata = mappass->fedata; 604 spin_lock_irqsave(&mappass->copy_lock, flags); 605 if (mappass->reqcopy.cmd == PVCALLS_POLL) { 606 rsp = RING_GET_RESPONSE(&fedata->ring, 607 fedata->ring.rsp_prod_pvt++); 608 rsp->req_id = mappass->reqcopy.req_id; 609 rsp->u.poll.id = mappass->reqcopy.u.poll.id; 610 rsp->cmd = mappass->reqcopy.cmd; 611 rsp->ret = 0; 612 613 mappass->reqcopy.cmd = 0; 614 spin_unlock_irqrestore(&mappass->copy_lock, flags); 615 616 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify); 617 if (notify) 618 notify_remote_via_irq(mappass->fedata->irq); 619 } else { 620 spin_unlock_irqrestore(&mappass->copy_lock, flags); 621 queue_work(mappass->wq, &mappass->register_work); 622 } 623 } 624 625 static int pvcalls_back_bind(struct xenbus_device *dev, 626 struct xen_pvcalls_request *req) 627 { 628 struct pvcalls_fedata *fedata; 629 int ret; 630 struct sockpass_mapping *map; 631 struct xen_pvcalls_response *rsp; 632 633 fedata = dev_get_drvdata(&dev->dev); 634 635 map = kzalloc(sizeof(*map), GFP_KERNEL); 636 if (map == NULL) { 637 ret = -ENOMEM; 638 goto out; 639 } 640 641 INIT_WORK(&map->register_work, __pvcalls_back_accept); 642 spin_lock_init(&map->copy_lock); 643 map->wq = alloc_ordered_workqueue("pvcalls_wq", 0); 644 if (!map->wq) { 645 ret = -ENOMEM; 646 goto out; 647 } 648 649 ret = sock_create(AF_INET, SOCK_STREAM, 0, &map->sock); 650 if (ret < 0) 651 goto out; 652 653 ret = inet_bind(map->sock, (struct sockaddr *)&req->u.bind.addr, 654 req->u.bind.len); 655 if (ret < 0) 656 goto out; 657 658 map->fedata = fedata; 659 map->id = req->u.bind.id; 660 661 down(&fedata->socket_lock); 662 ret = radix_tree_insert(&fedata->socketpass_mappings, map->id, 663 map); 664 up(&fedata->socket_lock); 665 if (ret) 666 goto out; 667 668 write_lock_bh(&map->sock->sk->sk_callback_lock); 669 map->saved_data_ready = map->sock->sk->sk_data_ready; 670 map->sock->sk->sk_user_data = map; 671 map->sock->sk->sk_data_ready = pvcalls_pass_sk_data_ready; 672 write_unlock_bh(&map->sock->sk->sk_callback_lock); 673 674 out: 675 if (ret) { 676 if (map && map->sock) 677 sock_release(map->sock); 678 if (map && map->wq) 679 destroy_workqueue(map->wq); 680 kfree(map); 681 } 682 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 683 rsp->req_id = req->req_id; 684 rsp->cmd = req->cmd; 685 rsp->u.bind.id = req->u.bind.id; 686 rsp->ret = ret; 687 return 0; 688 } 689 690 static int pvcalls_back_listen(struct xenbus_device *dev, 691 struct xen_pvcalls_request *req) 692 { 693 struct pvcalls_fedata *fedata; 694 int ret = -EINVAL; 695 struct sockpass_mapping *map; 696 struct xen_pvcalls_response *rsp; 697 698 fedata = dev_get_drvdata(&dev->dev); 699 700 down(&fedata->socket_lock); 701 map = radix_tree_lookup(&fedata->socketpass_mappings, req->u.listen.id); 702 up(&fedata->socket_lock); 703 if (map == NULL) 704 goto out; 705 706 ret = inet_listen(map->sock, req->u.listen.backlog); 707 708 out: 709 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 710 rsp->req_id = req->req_id; 711 rsp->cmd = req->cmd; 712 rsp->u.listen.id = req->u.listen.id; 713 rsp->ret = ret; 714 return 0; 715 } 716 717 static int pvcalls_back_accept(struct xenbus_device *dev, 718 struct xen_pvcalls_request *req) 719 { 720 struct pvcalls_fedata *fedata; 721 struct sockpass_mapping *mappass; 722 int ret = -EINVAL; 723 struct xen_pvcalls_response *rsp; 724 unsigned long flags; 725 726 fedata = dev_get_drvdata(&dev->dev); 727 728 down(&fedata->socket_lock); 729 mappass = radix_tree_lookup(&fedata->socketpass_mappings, 730 req->u.accept.id); 731 up(&fedata->socket_lock); 732 if (mappass == NULL) 733 goto out_error; 734 735 /* 736 * Limitation of the current implementation: only support one 737 * concurrent accept or poll call on one socket. 738 */ 739 spin_lock_irqsave(&mappass->copy_lock, flags); 740 if (mappass->reqcopy.cmd != 0) { 741 spin_unlock_irqrestore(&mappass->copy_lock, flags); 742 ret = -EINTR; 743 goto out_error; 744 } 745 746 mappass->reqcopy = *req; 747 spin_unlock_irqrestore(&mappass->copy_lock, flags); 748 queue_work(mappass->wq, &mappass->register_work); 749 750 /* Tell the caller we don't need to send back a notification yet */ 751 return -1; 752 753 out_error: 754 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 755 rsp->req_id = req->req_id; 756 rsp->cmd = req->cmd; 757 rsp->u.accept.id = req->u.accept.id; 758 rsp->ret = ret; 759 return 0; 760 } 761 762 static int pvcalls_back_poll(struct xenbus_device *dev, 763 struct xen_pvcalls_request *req) 764 { 765 struct pvcalls_fedata *fedata; 766 struct sockpass_mapping *mappass; 767 struct xen_pvcalls_response *rsp; 768 struct inet_connection_sock *icsk; 769 struct request_sock_queue *queue; 770 unsigned long flags; 771 int ret; 772 bool data; 773 774 fedata = dev_get_drvdata(&dev->dev); 775 776 down(&fedata->socket_lock); 777 mappass = radix_tree_lookup(&fedata->socketpass_mappings, 778 req->u.poll.id); 779 up(&fedata->socket_lock); 780 if (mappass == NULL) 781 return -EINVAL; 782 783 /* 784 * Limitation of the current implementation: only support one 785 * concurrent accept or poll call on one socket. 786 */ 787 spin_lock_irqsave(&mappass->copy_lock, flags); 788 if (mappass->reqcopy.cmd != 0) { 789 ret = -EINTR; 790 goto out; 791 } 792 793 mappass->reqcopy = *req; 794 icsk = inet_csk(mappass->sock->sk); 795 queue = &icsk->icsk_accept_queue; 796 data = READ_ONCE(queue->rskq_accept_head) != NULL; 797 if (data) { 798 mappass->reqcopy.cmd = 0; 799 ret = 0; 800 goto out; 801 } 802 spin_unlock_irqrestore(&mappass->copy_lock, flags); 803 804 /* Tell the caller we don't need to send back a notification yet */ 805 return -1; 806 807 out: 808 spin_unlock_irqrestore(&mappass->copy_lock, flags); 809 810 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 811 rsp->req_id = req->req_id; 812 rsp->cmd = req->cmd; 813 rsp->u.poll.id = req->u.poll.id; 814 rsp->ret = ret; 815 return 0; 816 } 817 818 static int pvcalls_back_handle_cmd(struct xenbus_device *dev, 819 struct xen_pvcalls_request *req) 820 { 821 int ret = 0; 822 823 switch (req->cmd) { 824 case PVCALLS_SOCKET: 825 ret = pvcalls_back_socket(dev, req); 826 break; 827 case PVCALLS_CONNECT: 828 ret = pvcalls_back_connect(dev, req); 829 break; 830 case PVCALLS_RELEASE: 831 ret = pvcalls_back_release(dev, req); 832 break; 833 case PVCALLS_BIND: 834 ret = pvcalls_back_bind(dev, req); 835 break; 836 case PVCALLS_LISTEN: 837 ret = pvcalls_back_listen(dev, req); 838 break; 839 case PVCALLS_ACCEPT: 840 ret = pvcalls_back_accept(dev, req); 841 break; 842 case PVCALLS_POLL: 843 ret = pvcalls_back_poll(dev, req); 844 break; 845 default: 846 { 847 struct pvcalls_fedata *fedata; 848 struct xen_pvcalls_response *rsp; 849 850 fedata = dev_get_drvdata(&dev->dev); 851 rsp = RING_GET_RESPONSE( 852 &fedata->ring, fedata->ring.rsp_prod_pvt++); 853 rsp->req_id = req->req_id; 854 rsp->cmd = req->cmd; 855 rsp->ret = -ENOTSUPP; 856 break; 857 } 858 } 859 return ret; 860 } 861 862 static void pvcalls_back_work(struct pvcalls_fedata *fedata) 863 { 864 int notify, notify_all = 0, more = 1; 865 struct xen_pvcalls_request req; 866 struct xenbus_device *dev = fedata->dev; 867 868 while (more) { 869 while (RING_HAS_UNCONSUMED_REQUESTS(&fedata->ring)) { 870 RING_COPY_REQUEST(&fedata->ring, 871 fedata->ring.req_cons++, 872 &req); 873 874 if (!pvcalls_back_handle_cmd(dev, &req)) { 875 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY( 876 &fedata->ring, notify); 877 notify_all += notify; 878 } 879 } 880 881 if (notify_all) { 882 notify_remote_via_irq(fedata->irq); 883 notify_all = 0; 884 } 885 886 RING_FINAL_CHECK_FOR_REQUESTS(&fedata->ring, more); 887 } 888 } 889 890 static irqreturn_t pvcalls_back_event(int irq, void *dev_id) 891 { 892 struct xenbus_device *dev = dev_id; 893 struct pvcalls_fedata *fedata = NULL; 894 unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS; 895 896 if (dev) { 897 fedata = dev_get_drvdata(&dev->dev); 898 if (fedata) { 899 pvcalls_back_work(fedata); 900 eoi_flags = 0; 901 } 902 } 903 904 xen_irq_lateeoi(irq, eoi_flags); 905 906 return IRQ_HANDLED; 907 } 908 909 static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map) 910 { 911 struct sock_mapping *map = sock_map; 912 struct pvcalls_ioworker *iow; 913 914 if (map == NULL || map->sock == NULL || map->sock->sk == NULL || 915 map->sock->sk->sk_user_data != map) { 916 xen_irq_lateeoi(irq, 0); 917 return IRQ_HANDLED; 918 } 919 920 iow = &map->ioworker; 921 922 atomic_inc(&map->write); 923 atomic_inc(&map->eoi); 924 atomic_inc(&map->io); 925 queue_work(iow->wq, &iow->register_work); 926 927 return IRQ_HANDLED; 928 } 929 930 static int backend_connect(struct xenbus_device *dev) 931 { 932 int err; 933 evtchn_port_t evtchn; 934 grant_ref_t ring_ref; 935 struct pvcalls_fedata *fedata = NULL; 936 937 fedata = kzalloc(sizeof(struct pvcalls_fedata), GFP_KERNEL); 938 if (!fedata) 939 return -ENOMEM; 940 941 fedata->irq = -1; 942 err = xenbus_scanf(XBT_NIL, dev->otherend, "port", "%u", 943 &evtchn); 944 if (err != 1) { 945 err = -EINVAL; 946 xenbus_dev_fatal(dev, err, "reading %s/event-channel", 947 dev->otherend); 948 goto error; 949 } 950 951 err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", "%u", &ring_ref); 952 if (err != 1) { 953 err = -EINVAL; 954 xenbus_dev_fatal(dev, err, "reading %s/ring-ref", 955 dev->otherend); 956 goto error; 957 } 958 959 err = bind_interdomain_evtchn_to_irq_lateeoi(dev, evtchn); 960 if (err < 0) 961 goto error; 962 fedata->irq = err; 963 964 err = request_threaded_irq(fedata->irq, NULL, pvcalls_back_event, 965 IRQF_ONESHOT, "pvcalls-back", dev); 966 if (err < 0) 967 goto error; 968 969 err = xenbus_map_ring_valloc(dev, &ring_ref, 1, 970 (void **)&fedata->sring); 971 if (err < 0) 972 goto error; 973 974 BACK_RING_INIT(&fedata->ring, fedata->sring, XEN_PAGE_SIZE * 1); 975 fedata->dev = dev; 976 977 INIT_LIST_HEAD(&fedata->socket_mappings); 978 INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL); 979 sema_init(&fedata->socket_lock, 1); 980 dev_set_drvdata(&dev->dev, fedata); 981 982 down(&pvcalls_back_global.frontends_lock); 983 list_add_tail(&fedata->list, &pvcalls_back_global.frontends); 984 up(&pvcalls_back_global.frontends_lock); 985 986 return 0; 987 988 error: 989 if (fedata->irq >= 0) 990 unbind_from_irqhandler(fedata->irq, dev); 991 if (fedata->sring != NULL) 992 xenbus_unmap_ring_vfree(dev, fedata->sring); 993 kfree(fedata); 994 return err; 995 } 996 997 static int backend_disconnect(struct xenbus_device *dev) 998 { 999 struct pvcalls_fedata *fedata; 1000 struct sock_mapping *map, *n; 1001 struct sockpass_mapping *mappass; 1002 struct radix_tree_iter iter; 1003 void **slot; 1004 1005 1006 fedata = dev_get_drvdata(&dev->dev); 1007 1008 down(&fedata->socket_lock); 1009 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) { 1010 list_del(&map->list); 1011 pvcalls_back_release_active(dev, fedata, map); 1012 } 1013 1014 radix_tree_for_each_slot(slot, &fedata->socketpass_mappings, &iter, 0) { 1015 mappass = radix_tree_deref_slot(slot); 1016 if (!mappass) 1017 continue; 1018 if (radix_tree_exception(mappass)) { 1019 if (radix_tree_deref_retry(mappass)) 1020 slot = radix_tree_iter_retry(&iter); 1021 } else { 1022 radix_tree_delete(&fedata->socketpass_mappings, 1023 mappass->id); 1024 pvcalls_back_release_passive(dev, fedata, mappass); 1025 } 1026 } 1027 up(&fedata->socket_lock); 1028 1029 unbind_from_irqhandler(fedata->irq, dev); 1030 xenbus_unmap_ring_vfree(dev, fedata->sring); 1031 1032 list_del(&fedata->list); 1033 kfree(fedata); 1034 dev_set_drvdata(&dev->dev, NULL); 1035 1036 return 0; 1037 } 1038 1039 static int pvcalls_back_probe(struct xenbus_device *dev, 1040 const struct xenbus_device_id *id) 1041 { 1042 int err, abort; 1043 struct xenbus_transaction xbt; 1044 1045 again: 1046 abort = 1; 1047 1048 err = xenbus_transaction_start(&xbt); 1049 if (err) { 1050 pr_warn("%s cannot create xenstore transaction\n", __func__); 1051 return err; 1052 } 1053 1054 err = xenbus_printf(xbt, dev->nodename, "versions", "%s", 1055 PVCALLS_VERSIONS); 1056 if (err) { 1057 pr_warn("%s write out 'versions' failed\n", __func__); 1058 goto abort; 1059 } 1060 1061 err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u", 1062 MAX_RING_ORDER); 1063 if (err) { 1064 pr_warn("%s write out 'max-page-order' failed\n", __func__); 1065 goto abort; 1066 } 1067 1068 err = xenbus_printf(xbt, dev->nodename, "function-calls", 1069 XENBUS_FUNCTIONS_CALLS); 1070 if (err) { 1071 pr_warn("%s write out 'function-calls' failed\n", __func__); 1072 goto abort; 1073 } 1074 1075 abort = 0; 1076 abort: 1077 err = xenbus_transaction_end(xbt, abort); 1078 if (err) { 1079 if (err == -EAGAIN && !abort) 1080 goto again; 1081 pr_warn("%s cannot complete xenstore transaction\n", __func__); 1082 return err; 1083 } 1084 1085 if (abort) 1086 return -EFAULT; 1087 1088 xenbus_switch_state(dev, XenbusStateInitWait); 1089 1090 return 0; 1091 } 1092 1093 static void set_backend_state(struct xenbus_device *dev, 1094 enum xenbus_state state) 1095 { 1096 while (dev->state != state) { 1097 switch (dev->state) { 1098 case XenbusStateClosed: 1099 switch (state) { 1100 case XenbusStateInitWait: 1101 case XenbusStateConnected: 1102 xenbus_switch_state(dev, XenbusStateInitWait); 1103 break; 1104 case XenbusStateClosing: 1105 xenbus_switch_state(dev, XenbusStateClosing); 1106 break; 1107 default: 1108 WARN_ON(1); 1109 } 1110 break; 1111 case XenbusStateInitWait: 1112 case XenbusStateInitialised: 1113 switch (state) { 1114 case XenbusStateConnected: 1115 if (backend_connect(dev)) 1116 return; 1117 xenbus_switch_state(dev, XenbusStateConnected); 1118 break; 1119 case XenbusStateClosing: 1120 case XenbusStateClosed: 1121 xenbus_switch_state(dev, XenbusStateClosing); 1122 break; 1123 default: 1124 WARN_ON(1); 1125 } 1126 break; 1127 case XenbusStateConnected: 1128 switch (state) { 1129 case XenbusStateInitWait: 1130 case XenbusStateClosing: 1131 case XenbusStateClosed: 1132 down(&pvcalls_back_global.frontends_lock); 1133 backend_disconnect(dev); 1134 up(&pvcalls_back_global.frontends_lock); 1135 xenbus_switch_state(dev, XenbusStateClosing); 1136 break; 1137 default: 1138 WARN_ON(1); 1139 } 1140 break; 1141 case XenbusStateClosing: 1142 switch (state) { 1143 case XenbusStateInitWait: 1144 case XenbusStateConnected: 1145 case XenbusStateClosed: 1146 xenbus_switch_state(dev, XenbusStateClosed); 1147 break; 1148 default: 1149 WARN_ON(1); 1150 } 1151 break; 1152 default: 1153 WARN_ON(1); 1154 } 1155 } 1156 } 1157 1158 static void pvcalls_back_changed(struct xenbus_device *dev, 1159 enum xenbus_state frontend_state) 1160 { 1161 switch (frontend_state) { 1162 case XenbusStateInitialising: 1163 set_backend_state(dev, XenbusStateInitWait); 1164 break; 1165 1166 case XenbusStateInitialised: 1167 case XenbusStateConnected: 1168 set_backend_state(dev, XenbusStateConnected); 1169 break; 1170 1171 case XenbusStateClosing: 1172 set_backend_state(dev, XenbusStateClosing); 1173 break; 1174 1175 case XenbusStateClosed: 1176 set_backend_state(dev, XenbusStateClosed); 1177 if (xenbus_dev_is_online(dev)) 1178 break; 1179 device_unregister(&dev->dev); 1180 break; 1181 case XenbusStateUnknown: 1182 set_backend_state(dev, XenbusStateClosed); 1183 device_unregister(&dev->dev); 1184 break; 1185 1186 default: 1187 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", 1188 frontend_state); 1189 break; 1190 } 1191 } 1192 1193 static void pvcalls_back_remove(struct xenbus_device *dev) 1194 { 1195 } 1196 1197 static int pvcalls_back_uevent(const struct xenbus_device *xdev, 1198 struct kobj_uevent_env *env) 1199 { 1200 return 0; 1201 } 1202 1203 static const struct xenbus_device_id pvcalls_back_ids[] = { 1204 { "pvcalls" }, 1205 { "" } 1206 }; 1207 1208 static struct xenbus_driver pvcalls_back_driver = { 1209 .ids = pvcalls_back_ids, 1210 .probe = pvcalls_back_probe, 1211 .remove = pvcalls_back_remove, 1212 .uevent = pvcalls_back_uevent, 1213 .otherend_changed = pvcalls_back_changed, 1214 }; 1215 1216 static int __init pvcalls_back_init(void) 1217 { 1218 int ret; 1219 1220 if (!xen_domain()) 1221 return -ENODEV; 1222 1223 ret = xenbus_register_backend(&pvcalls_back_driver); 1224 if (ret < 0) 1225 return ret; 1226 1227 sema_init(&pvcalls_back_global.frontends_lock, 1); 1228 INIT_LIST_HEAD(&pvcalls_back_global.frontends); 1229 return 0; 1230 } 1231 module_init(pvcalls_back_init); 1232 1233 static void __exit pvcalls_back_fin(void) 1234 { 1235 struct pvcalls_fedata *fedata, *nfedata; 1236 1237 down(&pvcalls_back_global.frontends_lock); 1238 list_for_each_entry_safe(fedata, nfedata, 1239 &pvcalls_back_global.frontends, list) { 1240 backend_disconnect(fedata->dev); 1241 } 1242 up(&pvcalls_back_global.frontends_lock); 1243 1244 xenbus_unregister_driver(&pvcalls_back_driver); 1245 } 1246 1247 module_exit(pvcalls_back_fin); 1248 1249 MODULE_DESCRIPTION("Xen PV Calls backend driver"); 1250 MODULE_AUTHOR("Stefano Stabellini <sstabellini@kernel.org>"); 1251 MODULE_LICENSE("GPL"); 1252