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