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 28static 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 */ 38struct 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 49struct pvcalls_ioworker { 50 struct work_struct register_work; 51 struct workqueue_struct *wq; 52}; 53 54struct 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 75struct 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 87static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map); 88static int pvcalls_back_release_active(struct xenbus_device *dev, 89 struct pvcalls_fedata *fedata, 90 struct sock_mapping *map); 91 92static 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 168static 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 230static 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 261static 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 289static 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 300static 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 316static 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; 384out: 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 392static 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 426out: 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 436static 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 461static 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 478static 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 507out: 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 516static 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 goto out_error; 565 } 566 567 map->sockpass = mappass; 568 iow = &map->ioworker; 569 atomic_inc(&map->read); 570 atomic_inc(&map->io); 571 queue_work(iow->wq, &iow->register_work); 572 573out_error: 574 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 575 rsp->req_id = req->req_id; 576 rsp->cmd = req->cmd; 577 rsp->u.accept.id = req->u.accept.id; 578 rsp->ret = ret; 579 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify); 580 if (notify) 581 notify_remote_via_irq(fedata->irq); 582 583 mappass->reqcopy.cmd = 0; 584} 585 586static void pvcalls_pass_sk_data_ready(struct sock *sock) 587{ 588 struct sockpass_mapping *mappass = sock->sk_user_data; 589 struct pvcalls_fedata *fedata; 590 struct xen_pvcalls_response *rsp; 591 unsigned long flags; 592 int notify; 593 594 trace_sk_data_ready(sock); 595 596 if (mappass == NULL) 597 return; 598 599 fedata = mappass->fedata; 600 spin_lock_irqsave(&mappass->copy_lock, flags); 601 if (mappass->reqcopy.cmd == PVCALLS_POLL) { 602 rsp = RING_GET_RESPONSE(&fedata->ring, 603 fedata->ring.rsp_prod_pvt++); 604 rsp->req_id = mappass->reqcopy.req_id; 605 rsp->u.poll.id = mappass->reqcopy.u.poll.id; 606 rsp->cmd = mappass->reqcopy.cmd; 607 rsp->ret = 0; 608 609 mappass->reqcopy.cmd = 0; 610 spin_unlock_irqrestore(&mappass->copy_lock, flags); 611 612 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&fedata->ring, notify); 613 if (notify) 614 notify_remote_via_irq(mappass->fedata->irq); 615 } else { 616 spin_unlock_irqrestore(&mappass->copy_lock, flags); 617 queue_work(mappass->wq, &mappass->register_work); 618 } 619} 620 621static int pvcalls_back_bind(struct xenbus_device *dev, 622 struct xen_pvcalls_request *req) 623{ 624 struct pvcalls_fedata *fedata; 625 int ret; 626 struct sockpass_mapping *map; 627 struct xen_pvcalls_response *rsp; 628 629 fedata = dev_get_drvdata(&dev->dev); 630 631 map = kzalloc(sizeof(*map), GFP_KERNEL); 632 if (map == NULL) { 633 ret = -ENOMEM; 634 goto out; 635 } 636 637 INIT_WORK(&map->register_work, __pvcalls_back_accept); 638 spin_lock_init(&map->copy_lock); 639 map->wq = alloc_ordered_workqueue("pvcalls_wq", 0); 640 if (!map->wq) { 641 ret = -ENOMEM; 642 goto out; 643 } 644 645 ret = sock_create(AF_INET, SOCK_STREAM, 0, &map->sock); 646 if (ret < 0) 647 goto out; 648 649 ret = inet_bind(map->sock, (struct sockaddr *)&req->u.bind.addr, 650 req->u.bind.len); 651 if (ret < 0) 652 goto out; 653 654 map->fedata = fedata; 655 map->id = req->u.bind.id; 656 657 down(&fedata->socket_lock); 658 ret = radix_tree_insert(&fedata->socketpass_mappings, map->id, 659 map); 660 up(&fedata->socket_lock); 661 if (ret) 662 goto out; 663 664 write_lock_bh(&map->sock->sk->sk_callback_lock); 665 map->saved_data_ready = map->sock->sk->sk_data_ready; 666 map->sock->sk->sk_user_data = map; 667 map->sock->sk->sk_data_ready = pvcalls_pass_sk_data_ready; 668 write_unlock_bh(&map->sock->sk->sk_callback_lock); 669 670out: 671 if (ret) { 672 if (map && map->sock) 673 sock_release(map->sock); 674 if (map && map->wq) 675 destroy_workqueue(map->wq); 676 kfree(map); 677 } 678 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 679 rsp->req_id = req->req_id; 680 rsp->cmd = req->cmd; 681 rsp->u.bind.id = req->u.bind.id; 682 rsp->ret = ret; 683 return 0; 684} 685 686static int pvcalls_back_listen(struct xenbus_device *dev, 687 struct xen_pvcalls_request *req) 688{ 689 struct pvcalls_fedata *fedata; 690 int ret = -EINVAL; 691 struct sockpass_mapping *map; 692 struct xen_pvcalls_response *rsp; 693 694 fedata = dev_get_drvdata(&dev->dev); 695 696 down(&fedata->socket_lock); 697 map = radix_tree_lookup(&fedata->socketpass_mappings, req->u.listen.id); 698 up(&fedata->socket_lock); 699 if (map == NULL) 700 goto out; 701 702 ret = inet_listen(map->sock, req->u.listen.backlog); 703 704out: 705 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 706 rsp->req_id = req->req_id; 707 rsp->cmd = req->cmd; 708 rsp->u.listen.id = req->u.listen.id; 709 rsp->ret = ret; 710 return 0; 711} 712 713static int pvcalls_back_accept(struct xenbus_device *dev, 714 struct xen_pvcalls_request *req) 715{ 716 struct pvcalls_fedata *fedata; 717 struct sockpass_mapping *mappass; 718 int ret = -EINVAL; 719 struct xen_pvcalls_response *rsp; 720 unsigned long flags; 721 722 fedata = dev_get_drvdata(&dev->dev); 723 724 down(&fedata->socket_lock); 725 mappass = radix_tree_lookup(&fedata->socketpass_mappings, 726 req->u.accept.id); 727 up(&fedata->socket_lock); 728 if (mappass == NULL) 729 goto out_error; 730 731 /* 732 * Limitation of the current implementation: only support one 733 * concurrent accept or poll call on one socket. 734 */ 735 spin_lock_irqsave(&mappass->copy_lock, flags); 736 if (mappass->reqcopy.cmd != 0) { 737 spin_unlock_irqrestore(&mappass->copy_lock, flags); 738 ret = -EINTR; 739 goto out_error; 740 } 741 742 mappass->reqcopy = *req; 743 spin_unlock_irqrestore(&mappass->copy_lock, flags); 744 queue_work(mappass->wq, &mappass->register_work); 745 746 /* Tell the caller we don't need to send back a notification yet */ 747 return -1; 748 749out_error: 750 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 751 rsp->req_id = req->req_id; 752 rsp->cmd = req->cmd; 753 rsp->u.accept.id = req->u.accept.id; 754 rsp->ret = ret; 755 return 0; 756} 757 758static int pvcalls_back_poll(struct xenbus_device *dev, 759 struct xen_pvcalls_request *req) 760{ 761 struct pvcalls_fedata *fedata; 762 struct sockpass_mapping *mappass; 763 struct xen_pvcalls_response *rsp; 764 struct inet_connection_sock *icsk; 765 struct request_sock_queue *queue; 766 unsigned long flags; 767 int ret; 768 bool data; 769 770 fedata = dev_get_drvdata(&dev->dev); 771 772 down(&fedata->socket_lock); 773 mappass = radix_tree_lookup(&fedata->socketpass_mappings, 774 req->u.poll.id); 775 up(&fedata->socket_lock); 776 if (mappass == NULL) 777 return -EINVAL; 778 779 /* 780 * Limitation of the current implementation: only support one 781 * concurrent accept or poll call on one socket. 782 */ 783 spin_lock_irqsave(&mappass->copy_lock, flags); 784 if (mappass->reqcopy.cmd != 0) { 785 ret = -EINTR; 786 goto out; 787 } 788 789 mappass->reqcopy = *req; 790 icsk = inet_csk(mappass->sock->sk); 791 queue = &icsk->icsk_accept_queue; 792 data = READ_ONCE(queue->rskq_accept_head) != NULL; 793 if (data) { 794 mappass->reqcopy.cmd = 0; 795 ret = 0; 796 goto out; 797 } 798 spin_unlock_irqrestore(&mappass->copy_lock, flags); 799 800 /* Tell the caller we don't need to send back a notification yet */ 801 return -1; 802 803out: 804 spin_unlock_irqrestore(&mappass->copy_lock, flags); 805 806 rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); 807 rsp->req_id = req->req_id; 808 rsp->cmd = req->cmd; 809 rsp->u.poll.id = req->u.poll.id; 810 rsp->ret = ret; 811 return 0; 812} 813 814static int pvcalls_back_handle_cmd(struct xenbus_device *dev, 815 struct xen_pvcalls_request *req) 816{ 817 int ret = 0; 818 819 switch (req->cmd) { 820 case PVCALLS_SOCKET: 821 ret = pvcalls_back_socket(dev, req); 822 break; 823 case PVCALLS_CONNECT: 824 ret = pvcalls_back_connect(dev, req); 825 break; 826 case PVCALLS_RELEASE: 827 ret = pvcalls_back_release(dev, req); 828 break; 829 case PVCALLS_BIND: 830 ret = pvcalls_back_bind(dev, req); 831 break; 832 case PVCALLS_LISTEN: 833 ret = pvcalls_back_listen(dev, req); 834 break; 835 case PVCALLS_ACCEPT: 836 ret = pvcalls_back_accept(dev, req); 837 break; 838 case PVCALLS_POLL: 839 ret = pvcalls_back_poll(dev, req); 840 break; 841 default: 842 { 843 struct pvcalls_fedata *fedata; 844 struct xen_pvcalls_response *rsp; 845 846 fedata = dev_get_drvdata(&dev->dev); 847 rsp = RING_GET_RESPONSE( 848 &fedata->ring, fedata->ring.rsp_prod_pvt++); 849 rsp->req_id = req->req_id; 850 rsp->cmd = req->cmd; 851 rsp->ret = -ENOTSUPP; 852 break; 853 } 854 } 855 return ret; 856} 857 858static void pvcalls_back_work(struct pvcalls_fedata *fedata) 859{ 860 int notify, notify_all = 0, more = 1; 861 struct xen_pvcalls_request req; 862 struct xenbus_device *dev = fedata->dev; 863 864 while (more) { 865 while (RING_HAS_UNCONSUMED_REQUESTS(&fedata->ring)) { 866 RING_COPY_REQUEST(&fedata->ring, 867 fedata->ring.req_cons++, 868 &req); 869 870 if (!pvcalls_back_handle_cmd(dev, &req)) { 871 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY( 872 &fedata->ring, notify); 873 notify_all += notify; 874 } 875 } 876 877 if (notify_all) { 878 notify_remote_via_irq(fedata->irq); 879 notify_all = 0; 880 } 881 882 RING_FINAL_CHECK_FOR_REQUESTS(&fedata->ring, more); 883 } 884} 885 886static irqreturn_t pvcalls_back_event(int irq, void *dev_id) 887{ 888 struct xenbus_device *dev = dev_id; 889 struct pvcalls_fedata *fedata = NULL; 890 unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS; 891 892 if (dev) { 893 fedata = dev_get_drvdata(&dev->dev); 894 if (fedata) { 895 pvcalls_back_work(fedata); 896 eoi_flags = 0; 897 } 898 } 899 900 xen_irq_lateeoi(irq, eoi_flags); 901 902 return IRQ_HANDLED; 903} 904 905static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map) 906{ 907 struct sock_mapping *map = sock_map; 908 struct pvcalls_ioworker *iow; 909 910 if (map == NULL || map->sock == NULL || map->sock->sk == NULL || 911 map->sock->sk->sk_user_data != map) { 912 xen_irq_lateeoi(irq, 0); 913 return IRQ_HANDLED; 914 } 915 916 iow = &map->ioworker; 917 918 atomic_inc(&map->write); 919 atomic_inc(&map->eoi); 920 atomic_inc(&map->io); 921 queue_work(iow->wq, &iow->register_work); 922 923 return IRQ_HANDLED; 924} 925 926static int backend_connect(struct xenbus_device *dev) 927{ 928 int err; 929 evtchn_port_t evtchn; 930 grant_ref_t ring_ref; 931 struct pvcalls_fedata *fedata = NULL; 932 933 fedata = kzalloc(sizeof(struct pvcalls_fedata), GFP_KERNEL); 934 if (!fedata) 935 return -ENOMEM; 936 937 fedata->irq = -1; 938 err = xenbus_scanf(XBT_NIL, dev->otherend, "port", "%u", 939 &evtchn); 940 if (err != 1) { 941 err = -EINVAL; 942 xenbus_dev_fatal(dev, err, "reading %s/event-channel", 943 dev->otherend); 944 goto error; 945 } 946 947 err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", "%u", &ring_ref); 948 if (err != 1) { 949 err = -EINVAL; 950 xenbus_dev_fatal(dev, err, "reading %s/ring-ref", 951 dev->otherend); 952 goto error; 953 } 954 955 err = bind_interdomain_evtchn_to_irq_lateeoi(dev, evtchn); 956 if (err < 0) 957 goto error; 958 fedata->irq = err; 959 960 err = request_threaded_irq(fedata->irq, NULL, pvcalls_back_event, 961 IRQF_ONESHOT, "pvcalls-back", dev); 962 if (err < 0) 963 goto error; 964 965 err = xenbus_map_ring_valloc(dev, &ring_ref, 1, 966 (void **)&fedata->sring); 967 if (err < 0) 968 goto error; 969 970 BACK_RING_INIT(&fedata->ring, fedata->sring, XEN_PAGE_SIZE * 1); 971 fedata->dev = dev; 972 973 INIT_LIST_HEAD(&fedata->socket_mappings); 974 INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL); 975 sema_init(&fedata->socket_lock, 1); 976 dev_set_drvdata(&dev->dev, fedata); 977 978 down(&pvcalls_back_global.frontends_lock); 979 list_add_tail(&fedata->list, &pvcalls_back_global.frontends); 980 up(&pvcalls_back_global.frontends_lock); 981 982 return 0; 983 984 error: 985 if (fedata->irq >= 0) 986 unbind_from_irqhandler(fedata->irq, dev); 987 if (fedata->sring != NULL) 988 xenbus_unmap_ring_vfree(dev, fedata->sring); 989 kfree(fedata); 990 return err; 991} 992 993static int backend_disconnect(struct xenbus_device *dev) 994{ 995 struct pvcalls_fedata *fedata; 996 struct sock_mapping *map, *n; 997 struct sockpass_mapping *mappass; 998 struct radix_tree_iter iter; 999 void **slot; 1000 1001 1002 fedata = dev_get_drvdata(&dev->dev); 1003 1004 down(&fedata->socket_lock); 1005 list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) { 1006 list_del(&map->list); 1007 pvcalls_back_release_active(dev, fedata, map); 1008 } 1009 1010 radix_tree_for_each_slot(slot, &fedata->socketpass_mappings, &iter, 0) { 1011 mappass = radix_tree_deref_slot(slot); 1012 if (!mappass) 1013 continue; 1014 if (radix_tree_exception(mappass)) { 1015 if (radix_tree_deref_retry(mappass)) 1016 slot = radix_tree_iter_retry(&iter); 1017 } else { 1018 radix_tree_delete(&fedata->socketpass_mappings, 1019 mappass->id); 1020 pvcalls_back_release_passive(dev, fedata, mappass); 1021 } 1022 } 1023 up(&fedata->socket_lock); 1024 1025 unbind_from_irqhandler(fedata->irq, dev); 1026 xenbus_unmap_ring_vfree(dev, fedata->sring); 1027 1028 list_del(&fedata->list); 1029 kfree(fedata); 1030 dev_set_drvdata(&dev->dev, NULL); 1031 1032 return 0; 1033} 1034 1035static int pvcalls_back_probe(struct xenbus_device *dev, 1036 const struct xenbus_device_id *id) 1037{ 1038 int err, abort; 1039 struct xenbus_transaction xbt; 1040 1041again: 1042 abort = 1; 1043 1044 err = xenbus_transaction_start(&xbt); 1045 if (err) { 1046 pr_warn("%s cannot create xenstore transaction\n", __func__); 1047 return err; 1048 } 1049 1050 err = xenbus_printf(xbt, dev->nodename, "versions", "%s", 1051 PVCALLS_VERSIONS); 1052 if (err) { 1053 pr_warn("%s write out 'versions' failed\n", __func__); 1054 goto abort; 1055 } 1056 1057 err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u", 1058 MAX_RING_ORDER); 1059 if (err) { 1060 pr_warn("%s write out 'max-page-order' failed\n", __func__); 1061 goto abort; 1062 } 1063 1064 err = xenbus_printf(xbt, dev->nodename, "function-calls", 1065 XENBUS_FUNCTIONS_CALLS); 1066 if (err) { 1067 pr_warn("%s write out 'function-calls' failed\n", __func__); 1068 goto abort; 1069 } 1070 1071 abort = 0; 1072abort: 1073 err = xenbus_transaction_end(xbt, abort); 1074 if (err) { 1075 if (err == -EAGAIN && !abort) 1076 goto again; 1077 pr_warn("%s cannot complete xenstore transaction\n", __func__); 1078 return err; 1079 } 1080 1081 if (abort) 1082 return -EFAULT; 1083 1084 xenbus_switch_state(dev, XenbusStateInitWait); 1085 1086 return 0; 1087} 1088 1089static void set_backend_state(struct xenbus_device *dev, 1090 enum xenbus_state state) 1091{ 1092 while (dev->state != state) { 1093 switch (dev->state) { 1094 case XenbusStateClosed: 1095 switch (state) { 1096 case XenbusStateInitWait: 1097 case XenbusStateConnected: 1098 xenbus_switch_state(dev, XenbusStateInitWait); 1099 break; 1100 case XenbusStateClosing: 1101 xenbus_switch_state(dev, XenbusStateClosing); 1102 break; 1103 default: 1104 WARN_ON(1); 1105 } 1106 break; 1107 case XenbusStateInitWait: 1108 case XenbusStateInitialised: 1109 switch (state) { 1110 case XenbusStateConnected: 1111 if (backend_connect(dev)) 1112 return; 1113 xenbus_switch_state(dev, XenbusStateConnected); 1114 break; 1115 case XenbusStateClosing: 1116 case XenbusStateClosed: 1117 xenbus_switch_state(dev, XenbusStateClosing); 1118 break; 1119 default: 1120 WARN_ON(1); 1121 } 1122 break; 1123 case XenbusStateConnected: 1124 switch (state) { 1125 case XenbusStateInitWait: 1126 case XenbusStateClosing: 1127 case XenbusStateClosed: 1128 down(&pvcalls_back_global.frontends_lock); 1129 backend_disconnect(dev); 1130 up(&pvcalls_back_global.frontends_lock); 1131 xenbus_switch_state(dev, XenbusStateClosing); 1132 break; 1133 default: 1134 WARN_ON(1); 1135 } 1136 break; 1137 case XenbusStateClosing: 1138 switch (state) { 1139 case XenbusStateInitWait: 1140 case XenbusStateConnected: 1141 case XenbusStateClosed: 1142 xenbus_switch_state(dev, XenbusStateClosed); 1143 break; 1144 default: 1145 WARN_ON(1); 1146 } 1147 break; 1148 default: 1149 WARN_ON(1); 1150 } 1151 } 1152} 1153 1154static void pvcalls_back_changed(struct xenbus_device *dev, 1155 enum xenbus_state frontend_state) 1156{ 1157 switch (frontend_state) { 1158 case XenbusStateInitialising: 1159 set_backend_state(dev, XenbusStateInitWait); 1160 break; 1161 1162 case XenbusStateInitialised: 1163 case XenbusStateConnected: 1164 set_backend_state(dev, XenbusStateConnected); 1165 break; 1166 1167 case XenbusStateClosing: 1168 set_backend_state(dev, XenbusStateClosing); 1169 break; 1170 1171 case XenbusStateClosed: 1172 set_backend_state(dev, XenbusStateClosed); 1173 if (xenbus_dev_is_online(dev)) 1174 break; 1175 device_unregister(&dev->dev); 1176 break; 1177 case XenbusStateUnknown: 1178 set_backend_state(dev, XenbusStateClosed); 1179 device_unregister(&dev->dev); 1180 break; 1181 1182 default: 1183 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", 1184 frontend_state); 1185 break; 1186 } 1187} 1188 1189static void pvcalls_back_remove(struct xenbus_device *dev) 1190{ 1191} 1192 1193static int pvcalls_back_uevent(const struct xenbus_device *xdev, 1194 struct kobj_uevent_env *env) 1195{ 1196 return 0; 1197} 1198 1199static const struct xenbus_device_id pvcalls_back_ids[] = { 1200 { "pvcalls" }, 1201 { "" } 1202}; 1203 1204static struct xenbus_driver pvcalls_back_driver = { 1205 .ids = pvcalls_back_ids, 1206 .probe = pvcalls_back_probe, 1207 .remove = pvcalls_back_remove, 1208 .uevent = pvcalls_back_uevent, 1209 .otherend_changed = pvcalls_back_changed, 1210}; 1211 1212static int __init pvcalls_back_init(void) 1213{ 1214 int ret; 1215 1216 if (!xen_domain()) 1217 return -ENODEV; 1218 1219 ret = xenbus_register_backend(&pvcalls_back_driver); 1220 if (ret < 0) 1221 return ret; 1222 1223 sema_init(&pvcalls_back_global.frontends_lock, 1); 1224 INIT_LIST_HEAD(&pvcalls_back_global.frontends); 1225 return 0; 1226} 1227module_init(pvcalls_back_init); 1228 1229static void __exit pvcalls_back_fin(void) 1230{ 1231 struct pvcalls_fedata *fedata, *nfedata; 1232 1233 down(&pvcalls_back_global.frontends_lock); 1234 list_for_each_entry_safe(fedata, nfedata, 1235 &pvcalls_back_global.frontends, list) { 1236 backend_disconnect(fedata->dev); 1237 } 1238 up(&pvcalls_back_global.frontends_lock); 1239 1240 xenbus_unregister_driver(&pvcalls_back_driver); 1241} 1242 1243module_exit(pvcalls_back_fin); 1244 1245MODULE_DESCRIPTION("Xen PV Calls backend driver"); 1246MODULE_AUTHOR("Stefano Stabellini <sstabellini@kernel.org>"); 1247MODULE_LICENSE("GPL"); 1248