1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * Xenbus code for netif backend 4 * 5 * Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au> 6 * Copyright (C) 2005 XenSource Ltd 7*/ 8 9#include "common.h" 10#include <linux/vmalloc.h> 11#include <linux/rtnetlink.h> 12 13static int connect_data_rings(struct backend_info *be, 14 struct xenvif_queue *queue); 15static void connect(struct backend_info *be); 16static int read_xenbus_vif_flags(struct backend_info *be); 17static int backend_create_xenvif(struct backend_info *be); 18static void unregister_hotplug_status_watch(struct backend_info *be); 19static void xen_unregister_watchers(struct xenvif *vif); 20static void set_backend_state(struct backend_info *be, 21 enum xenbus_state state); 22 23#ifdef CONFIG_DEBUG_FS 24struct dentry *xen_netback_dbg_root = NULL; 25 26static int xenvif_read_io_ring(struct seq_file *m, void *v) 27{ 28 struct xenvif_queue *queue = m->private; 29 struct xen_netif_tx_back_ring *tx_ring = &queue->tx; 30 struct xen_netif_rx_back_ring *rx_ring = &queue->rx; 31 struct netdev_queue *dev_queue; 32 33 if (tx_ring->sring) { 34 struct xen_netif_tx_sring *sring = tx_ring->sring; 35 36 seq_printf(m, "Queue %d\nTX: nr_ents %u\n", queue->id, 37 tx_ring->nr_ents); 38 seq_printf(m, "req prod %u (%d) cons %u (%d) event %u (%d)\n", 39 sring->req_prod, 40 sring->req_prod - sring->rsp_prod, 41 tx_ring->req_cons, 42 tx_ring->req_cons - sring->rsp_prod, 43 sring->req_event, 44 sring->req_event - sring->rsp_prod); 45 seq_printf(m, "rsp prod %u (base) pvt %u (%d) event %u (%d)\n", 46 sring->rsp_prod, 47 tx_ring->rsp_prod_pvt, 48 tx_ring->rsp_prod_pvt - sring->rsp_prod, 49 sring->rsp_event, 50 sring->rsp_event - sring->rsp_prod); 51 seq_printf(m, "pending prod %u pending cons %u nr_pending_reqs %u\n", 52 queue->pending_prod, 53 queue->pending_cons, 54 nr_pending_reqs(queue)); 55 seq_printf(m, "dealloc prod %u dealloc cons %u dealloc_queue %u\n\n", 56 queue->dealloc_prod, 57 queue->dealloc_cons, 58 queue->dealloc_prod - queue->dealloc_cons); 59 } 60 61 if (rx_ring->sring) { 62 struct xen_netif_rx_sring *sring = rx_ring->sring; 63 64 seq_printf(m, "RX: nr_ents %u\n", rx_ring->nr_ents); 65 seq_printf(m, "req prod %u (%d) cons %u (%d) event %u (%d)\n", 66 sring->req_prod, 67 sring->req_prod - sring->rsp_prod, 68 rx_ring->req_cons, 69 rx_ring->req_cons - sring->rsp_prod, 70 sring->req_event, 71 sring->req_event - sring->rsp_prod); 72 seq_printf(m, "rsp prod %u (base) pvt %u (%d) event %u (%d)\n\n", 73 sring->rsp_prod, 74 rx_ring->rsp_prod_pvt, 75 rx_ring->rsp_prod_pvt - sring->rsp_prod, 76 sring->rsp_event, 77 sring->rsp_event - sring->rsp_prod); 78 } 79 80 seq_printf(m, "NAPI state: %lx NAPI weight: %d TX queue len %u\n" 81 "Credit timer_pending: %d, credit: %lu, usec: %lu\n" 82 "remaining: %lu, expires: %lu, now: %lu\n", 83 queue->napi.state, queue->napi.weight, 84 skb_queue_len(&queue->tx_queue), 85 timer_pending(&queue->credit_timeout), 86 queue->credit_bytes, 87 queue->credit_usec, 88 queue->remaining_credit, 89 queue->credit_timeout.expires, 90 jiffies); 91 92 dev_queue = netdev_get_tx_queue(queue->vif->dev, queue->id); 93 94 seq_printf(m, "\nRx internal queue: len %u max %u pkts %u %s\n", 95 queue->rx_queue_len, queue->rx_queue_max, 96 skb_queue_len(&queue->rx_queue), 97 netif_tx_queue_stopped(dev_queue) ? "stopped" : "running"); 98 99 return 0; 100} 101 102#define XENVIF_KICK_STR "kick" 103#define BUFFER_SIZE 32 104 105static ssize_t 106xenvif_write_io_ring(struct file *filp, const char __user *buf, size_t count, 107 loff_t *ppos) 108{ 109 struct xenvif_queue *queue = 110 ((struct seq_file *)filp->private_data)->private; 111 int len; 112 char write[BUFFER_SIZE]; 113 114 /* don't allow partial writes and check the length */ 115 if (*ppos != 0) 116 return 0; 117 if (count >= sizeof(write)) 118 return -ENOSPC; 119 120 len = simple_write_to_buffer(write, 121 sizeof(write) - 1, 122 ppos, 123 buf, 124 count); 125 if (len < 0) 126 return len; 127 128 write[len] = '\0'; 129 130 if (!strncmp(write, XENVIF_KICK_STR, sizeof(XENVIF_KICK_STR) - 1)) 131 xenvif_interrupt(0, (void *)queue); 132 else { 133 pr_warn("Unknown command to io_ring_q%d. Available: kick\n", 134 queue->id); 135 count = -EINVAL; 136 } 137 return count; 138} 139 140static int xenvif_io_ring_open(struct inode *inode, struct file *filp) 141{ 142 int ret; 143 void *queue = NULL; 144 145 if (inode->i_private) 146 queue = inode->i_private; 147 ret = single_open(filp, xenvif_read_io_ring, queue); 148 filp->f_mode |= FMODE_PWRITE; 149 return ret; 150} 151 152static const struct file_operations xenvif_dbg_io_ring_ops_fops = { 153 .owner = THIS_MODULE, 154 .open = xenvif_io_ring_open, 155 .read = seq_read, 156 .llseek = seq_lseek, 157 .release = single_release, 158 .write = xenvif_write_io_ring, 159}; 160 161static int xenvif_ctrl_show(struct seq_file *m, void *v) 162{ 163 struct xenvif *vif = m->private; 164 165 xenvif_dump_hash_info(vif, m); 166 167 return 0; 168} 169DEFINE_SHOW_ATTRIBUTE(xenvif_ctrl); 170 171static void xenvif_debugfs_addif(struct xenvif *vif) 172{ 173 int i; 174 175 vif->xenvif_dbg_root = debugfs_create_dir(vif->dev->name, 176 xen_netback_dbg_root); 177 for (i = 0; i < vif->num_queues; ++i) { 178 char filename[sizeof("io_ring_q") + 4]; 179 180 snprintf(filename, sizeof(filename), "io_ring_q%d", i); 181 debugfs_create_file(filename, 0600, vif->xenvif_dbg_root, 182 &vif->queues[i], 183 &xenvif_dbg_io_ring_ops_fops); 184 } 185 186 if (vif->ctrl_irq) 187 debugfs_create_file("ctrl", 0400, vif->xenvif_dbg_root, vif, 188 &xenvif_ctrl_fops); 189} 190 191static void xenvif_debugfs_delif(struct xenvif *vif) 192{ 193 debugfs_remove_recursive(vif->xenvif_dbg_root); 194 vif->xenvif_dbg_root = NULL; 195} 196#endif /* CONFIG_DEBUG_FS */ 197 198/* 199 * Handle the creation of the hotplug script environment. We add the script 200 * and vif variables to the environment, for the benefit of the vif-* hotplug 201 * scripts. 202 */ 203static int netback_uevent(const struct xenbus_device *xdev, 204 struct kobj_uevent_env *env) 205{ 206 struct backend_info *be = dev_get_drvdata(&xdev->dev); 207 208 if (!be) 209 return 0; 210 211 if (add_uevent_var(env, "script=%s", be->hotplug_script)) 212 return -ENOMEM; 213 214 if (!be->vif) 215 return 0; 216 217 return add_uevent_var(env, "vif=%s", be->vif->dev->name); 218} 219 220 221static int backend_create_xenvif(struct backend_info *be) 222{ 223 int err; 224 long handle; 225 struct xenbus_device *dev = be->dev; 226 struct xenvif *vif; 227 228 if (be->vif != NULL) 229 return 0; 230 231 err = xenbus_scanf(XBT_NIL, dev->nodename, "handle", "%li", &handle); 232 if (err != 1) { 233 xenbus_dev_fatal(dev, err, "reading handle"); 234 return (err < 0) ? err : -EINVAL; 235 } 236 237 vif = xenvif_alloc(&dev->dev, dev->otherend_id, handle); 238 if (IS_ERR(vif)) { 239 err = PTR_ERR(vif); 240 xenbus_dev_fatal(dev, err, "creating interface"); 241 return err; 242 } 243 be->vif = vif; 244 vif->be = be; 245 246 kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE); 247 return 0; 248} 249 250static void backend_disconnect(struct backend_info *be) 251{ 252 struct xenvif *vif = be->vif; 253 254 if (vif) { 255 unsigned int num_queues = vif->num_queues; 256 unsigned int queue_index; 257 258 xen_unregister_watchers(vif); 259#ifdef CONFIG_DEBUG_FS 260 xenvif_debugfs_delif(vif); 261#endif /* CONFIG_DEBUG_FS */ 262 xenvif_disconnect_data(vif); 263 264 /* At this point some of the handlers may still be active 265 * so we need to have additional synchronization here. 266 */ 267 vif->num_queues = 0; 268 synchronize_net(); 269 270 for (queue_index = 0; queue_index < num_queues; ++queue_index) 271 xenvif_deinit_queue(&vif->queues[queue_index]); 272 273 vfree(vif->queues); 274 vif->queues = NULL; 275 276 xenvif_disconnect_ctrl(vif); 277 } 278} 279 280static void backend_connect(struct backend_info *be) 281{ 282 if (be->vif) 283 connect(be); 284} 285 286static inline void backend_switch_state(struct backend_info *be, 287 enum xenbus_state state) 288{ 289 struct xenbus_device *dev = be->dev; 290 291 pr_debug("%s -> %s\n", dev->nodename, xenbus_strstate(state)); 292 be->state = state; 293 294 /* If we are waiting for a hotplug script then defer the 295 * actual xenbus state change. 296 */ 297 if (!be->have_hotplug_status_watch) 298 xenbus_switch_state(dev, state); 299} 300 301/* Handle backend state transitions: 302 * 303 * The backend state starts in Initialising and the following transitions are 304 * allowed. 305 * 306 * Initialising -> InitWait -> Connected 307 * \ 308 * \ ^ \ | 309 * \ | \ | 310 * \ | \ | 311 * \ | \ | 312 * \ | \ | 313 * \ | \ | 314 * V | V V 315 * 316 * Closed <-> Closing 317 * 318 * The state argument specifies the eventual state of the backend and the 319 * function transitions to that state via the shortest path. 320 */ 321static void set_backend_state(struct backend_info *be, 322 enum xenbus_state state) 323{ 324 while (be->state != state) { 325 switch (be->state) { 326 case XenbusStateInitialising: 327 switch (state) { 328 case XenbusStateInitWait: 329 case XenbusStateConnected: 330 case XenbusStateClosing: 331 backend_switch_state(be, XenbusStateInitWait); 332 break; 333 case XenbusStateClosed: 334 backend_switch_state(be, XenbusStateClosed); 335 break; 336 default: 337 BUG(); 338 } 339 break; 340 case XenbusStateClosed: 341 switch (state) { 342 case XenbusStateInitWait: 343 case XenbusStateConnected: 344 backend_switch_state(be, XenbusStateInitWait); 345 break; 346 case XenbusStateClosing: 347 backend_switch_state(be, XenbusStateClosing); 348 break; 349 default: 350 BUG(); 351 } 352 break; 353 case XenbusStateInitWait: 354 switch (state) { 355 case XenbusStateConnected: 356 backend_connect(be); 357 backend_switch_state(be, XenbusStateConnected); 358 break; 359 case XenbusStateClosing: 360 case XenbusStateClosed: 361 backend_switch_state(be, XenbusStateClosing); 362 break; 363 default: 364 BUG(); 365 } 366 break; 367 case XenbusStateConnected: 368 switch (state) { 369 case XenbusStateInitWait: 370 case XenbusStateClosing: 371 case XenbusStateClosed: 372 backend_disconnect(be); 373 backend_switch_state(be, XenbusStateClosing); 374 break; 375 default: 376 BUG(); 377 } 378 break; 379 case XenbusStateClosing: 380 switch (state) { 381 case XenbusStateInitWait: 382 case XenbusStateConnected: 383 case XenbusStateClosed: 384 backend_switch_state(be, XenbusStateClosed); 385 break; 386 default: 387 BUG(); 388 } 389 break; 390 default: 391 BUG(); 392 } 393 } 394} 395 396static void read_xenbus_frontend_xdp(struct backend_info *be, 397 struct xenbus_device *dev) 398{ 399 struct xenvif *vif = be->vif; 400 u16 headroom; 401 int err; 402 403 err = xenbus_scanf(XBT_NIL, dev->otherend, 404 "xdp-headroom", "%hu", &headroom); 405 if (err != 1) { 406 vif->xdp_headroom = 0; 407 return; 408 } 409 if (headroom > XEN_NETIF_MAX_XDP_HEADROOM) 410 headroom = XEN_NETIF_MAX_XDP_HEADROOM; 411 vif->xdp_headroom = headroom; 412} 413 414/* 415 * Callback received when the frontend's state changes. 416 */ 417static void frontend_changed(struct xenbus_device *dev, 418 enum xenbus_state frontend_state) 419{ 420 struct backend_info *be = dev_get_drvdata(&dev->dev); 421 422 pr_debug("%s -> %s\n", dev->otherend, xenbus_strstate(frontend_state)); 423 424 be->frontend_state = frontend_state; 425 426 switch (frontend_state) { 427 case XenbusStateInitialising: 428 set_backend_state(be, XenbusStateInitWait); 429 break; 430 431 case XenbusStateInitialised: 432 break; 433 434 case XenbusStateConnected: 435 set_backend_state(be, XenbusStateConnected); 436 break; 437 438 case XenbusStateReconfiguring: 439 read_xenbus_frontend_xdp(be, dev); 440 xenbus_switch_state(dev, XenbusStateReconfigured); 441 break; 442 443 case XenbusStateClosing: 444 set_backend_state(be, XenbusStateClosing); 445 break; 446 447 case XenbusStateClosed: 448 set_backend_state(be, XenbusStateClosed); 449 if (xenbus_dev_is_online(dev)) 450 break; 451 fallthrough; /* if not online */ 452 case XenbusStateUnknown: 453 set_backend_state(be, XenbusStateClosed); 454 device_unregister(&dev->dev); 455 break; 456 457 default: 458 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", 459 frontend_state); 460 break; 461 } 462} 463 464 465static void xen_net_read_rate(struct xenbus_device *dev, 466 unsigned long *bytes, unsigned long *usec) 467{ 468 char *s, *e; 469 unsigned long b, u; 470 char *ratestr; 471 472 /* Default to unlimited bandwidth. */ 473 *bytes = ~0UL; 474 *usec = 0; 475 476 ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL); 477 if (IS_ERR(ratestr)) 478 return; 479 480 s = ratestr; 481 b = simple_strtoul(s, &e, 10); 482 if ((s == e) || (*e != ',')) 483 goto fail; 484 485 s = e + 1; 486 u = simple_strtoul(s, &e, 10); 487 if ((s == e) || (*e != '\0')) 488 goto fail; 489 490 *bytes = b; 491 *usec = u; 492 493 kfree(ratestr); 494 return; 495 496 fail: 497 pr_warn("Failed to parse network rate limit. Traffic unlimited.\n"); 498 kfree(ratestr); 499} 500 501static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[]) 502{ 503 char *s, *e, *macstr; 504 int i; 505 506 macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL); 507 if (IS_ERR(macstr)) 508 return PTR_ERR(macstr); 509 510 for (i = 0; i < ETH_ALEN; i++) { 511 mac[i] = simple_strtoul(s, &e, 16); 512 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) { 513 kfree(macstr); 514 return -ENOENT; 515 } 516 s = e+1; 517 } 518 519 kfree(macstr); 520 return 0; 521} 522 523static void xen_net_rate_changed(struct xenbus_watch *watch, 524 const char *path, const char *token) 525{ 526 struct xenvif *vif = container_of(watch, struct xenvif, credit_watch); 527 struct xenbus_device *dev = xenvif_to_xenbus_device(vif); 528 unsigned long credit_bytes; 529 unsigned long credit_usec; 530 unsigned int queue_index; 531 532 xen_net_read_rate(dev, &credit_bytes, &credit_usec); 533 for (queue_index = 0; queue_index < vif->num_queues; queue_index++) { 534 struct xenvif_queue *queue = &vif->queues[queue_index]; 535 536 queue->credit_bytes = credit_bytes; 537 queue->credit_usec = credit_usec; 538 if (!mod_timer_pending(&queue->credit_timeout, jiffies) && 539 queue->remaining_credit > queue->credit_bytes) { 540 queue->remaining_credit = queue->credit_bytes; 541 } 542 } 543} 544 545static int xen_register_credit_watch(struct xenbus_device *dev, 546 struct xenvif *vif) 547{ 548 int err = 0; 549 char *node; 550 unsigned maxlen = strlen(dev->nodename) + sizeof("/rate"); 551 552 if (vif->credit_watch.node) 553 return -EADDRINUSE; 554 555 node = kmalloc(maxlen, GFP_KERNEL); 556 if (!node) 557 return -ENOMEM; 558 snprintf(node, maxlen, "%s/rate", dev->nodename); 559 vif->credit_watch.node = node; 560 vif->credit_watch.will_handle = NULL; 561 vif->credit_watch.callback = xen_net_rate_changed; 562 err = register_xenbus_watch(&vif->credit_watch); 563 if (err) { 564 pr_err("Failed to set watcher %s\n", vif->credit_watch.node); 565 kfree(node); 566 vif->credit_watch.node = NULL; 567 vif->credit_watch.will_handle = NULL; 568 vif->credit_watch.callback = NULL; 569 } 570 return err; 571} 572 573static void xen_unregister_credit_watch(struct xenvif *vif) 574{ 575 if (vif->credit_watch.node) { 576 unregister_xenbus_watch(&vif->credit_watch); 577 kfree(vif->credit_watch.node); 578 vif->credit_watch.node = NULL; 579 } 580} 581 582static void xen_mcast_ctrl_changed(struct xenbus_watch *watch, 583 const char *path, const char *token) 584{ 585 struct xenvif *vif = container_of(watch, struct xenvif, 586 mcast_ctrl_watch); 587 struct xenbus_device *dev = xenvif_to_xenbus_device(vif); 588 589 vif->multicast_control = !!xenbus_read_unsigned(dev->otherend, 590 "request-multicast-control", 0); 591} 592 593static int xen_register_mcast_ctrl_watch(struct xenbus_device *dev, 594 struct xenvif *vif) 595{ 596 int err = 0; 597 char *node; 598 unsigned maxlen = strlen(dev->otherend) + 599 sizeof("/request-multicast-control"); 600 601 if (vif->mcast_ctrl_watch.node) { 602 pr_err_ratelimited("Watch is already registered\n"); 603 return -EADDRINUSE; 604 } 605 606 node = kmalloc(maxlen, GFP_KERNEL); 607 if (!node) { 608 pr_err("Failed to allocate memory for watch\n"); 609 return -ENOMEM; 610 } 611 snprintf(node, maxlen, "%s/request-multicast-control", 612 dev->otherend); 613 vif->mcast_ctrl_watch.node = node; 614 vif->mcast_ctrl_watch.will_handle = NULL; 615 vif->mcast_ctrl_watch.callback = xen_mcast_ctrl_changed; 616 err = register_xenbus_watch(&vif->mcast_ctrl_watch); 617 if (err) { 618 pr_err("Failed to set watcher %s\n", 619 vif->mcast_ctrl_watch.node); 620 kfree(node); 621 vif->mcast_ctrl_watch.node = NULL; 622 vif->mcast_ctrl_watch.will_handle = NULL; 623 vif->mcast_ctrl_watch.callback = NULL; 624 } 625 return err; 626} 627 628static void xen_unregister_mcast_ctrl_watch(struct xenvif *vif) 629{ 630 if (vif->mcast_ctrl_watch.node) { 631 unregister_xenbus_watch(&vif->mcast_ctrl_watch); 632 kfree(vif->mcast_ctrl_watch.node); 633 vif->mcast_ctrl_watch.node = NULL; 634 } 635} 636 637static void xen_register_watchers(struct xenbus_device *dev, 638 struct xenvif *vif) 639{ 640 xen_register_credit_watch(dev, vif); 641 xen_register_mcast_ctrl_watch(dev, vif); 642} 643 644static void xen_unregister_watchers(struct xenvif *vif) 645{ 646 xen_unregister_mcast_ctrl_watch(vif); 647 xen_unregister_credit_watch(vif); 648} 649 650static void unregister_hotplug_status_watch(struct backend_info *be) 651{ 652 if (be->have_hotplug_status_watch) { 653 unregister_xenbus_watch(&be->hotplug_status_watch); 654 kfree(be->hotplug_status_watch.node); 655 } 656 be->have_hotplug_status_watch = 0; 657} 658 659static void hotplug_status_changed(struct xenbus_watch *watch, 660 const char *path, 661 const char *token) 662{ 663 struct backend_info *be = container_of(watch, 664 struct backend_info, 665 hotplug_status_watch); 666 char *str; 667 unsigned int len; 668 669 str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len); 670 if (IS_ERR(str)) 671 return; 672 if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) { 673 /* Complete any pending state change */ 674 xenbus_switch_state(be->dev, be->state); 675 676 /* Not interested in this watch anymore. */ 677 unregister_hotplug_status_watch(be); 678 } 679 kfree(str); 680} 681 682static int connect_ctrl_ring(struct backend_info *be) 683{ 684 struct xenbus_device *dev = be->dev; 685 struct xenvif *vif = be->vif; 686 unsigned int val; 687 grant_ref_t ring_ref; 688 unsigned int evtchn; 689 int err; 690 691 err = xenbus_scanf(XBT_NIL, dev->otherend, 692 "ctrl-ring-ref", "%u", &val); 693 if (err < 0) 694 goto done; /* The frontend does not have a control ring */ 695 696 ring_ref = val; 697 698 err = xenbus_scanf(XBT_NIL, dev->otherend, 699 "event-channel-ctrl", "%u", &val); 700 if (err < 0) { 701 xenbus_dev_fatal(dev, err, 702 "reading %s/event-channel-ctrl", 703 dev->otherend); 704 goto fail; 705 } 706 707 evtchn = val; 708 709 err = xenvif_connect_ctrl(vif, ring_ref, evtchn); 710 if (err) { 711 xenbus_dev_fatal(dev, err, 712 "mapping shared-frame %u port %u", 713 ring_ref, evtchn); 714 goto fail; 715 } 716 717done: 718 return 0; 719 720fail: 721 return err; 722} 723 724static void connect(struct backend_info *be) 725{ 726 int err; 727 struct xenbus_device *dev = be->dev; 728 unsigned long credit_bytes, credit_usec; 729 unsigned int queue_index; 730 unsigned int requested_num_queues; 731 struct xenvif_queue *queue; 732 733 /* Check whether the frontend requested multiple queues 734 * and read the number requested. 735 */ 736 requested_num_queues = xenbus_read_unsigned(dev->otherend, 737 "multi-queue-num-queues", 1); 738 if (requested_num_queues > xenvif_max_queues) { 739 /* buggy or malicious guest */ 740 xenbus_dev_fatal(dev, -EINVAL, 741 "guest requested %u queues, exceeding the maximum of %u.", 742 requested_num_queues, xenvif_max_queues); 743 return; 744 } 745 746 err = xen_net_read_mac(dev, be->vif->fe_dev_addr); 747 if (err) { 748 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename); 749 return; 750 } 751 752 xen_net_read_rate(dev, &credit_bytes, &credit_usec); 753 xen_unregister_watchers(be->vif); 754 xen_register_watchers(dev, be->vif); 755 read_xenbus_vif_flags(be); 756 757 err = connect_ctrl_ring(be); 758 if (err) { 759 xenbus_dev_fatal(dev, err, "connecting control ring"); 760 return; 761 } 762 763 /* Use the number of queues requested by the frontend */ 764 be->vif->queues = vzalloc(array_size(requested_num_queues, 765 sizeof(struct xenvif_queue))); 766 if (!be->vif->queues) { 767 xenbus_dev_fatal(dev, -ENOMEM, 768 "allocating queues"); 769 return; 770 } 771 772 be->vif->num_queues = requested_num_queues; 773 be->vif->stalled_queues = requested_num_queues; 774 775 for (queue_index = 0; queue_index < requested_num_queues; ++queue_index) { 776 queue = &be->vif->queues[queue_index]; 777 queue->vif = be->vif; 778 queue->id = queue_index; 779 snprintf(queue->name, sizeof(queue->name), "%s-q%u", 780 be->vif->dev->name, queue->id); 781 782 err = xenvif_init_queue(queue); 783 if (err) { 784 /* xenvif_init_queue() cleans up after itself on 785 * failure, but we need to clean up any previously 786 * initialised queues. Set num_queues to i so that 787 * earlier queues can be destroyed using the regular 788 * disconnect logic. 789 */ 790 be->vif->num_queues = queue_index; 791 goto err; 792 } 793 794 queue->credit_bytes = credit_bytes; 795 queue->remaining_credit = credit_bytes; 796 queue->credit_usec = credit_usec; 797 798 err = connect_data_rings(be, queue); 799 if (err) { 800 /* connect_data_rings() cleans up after itself on 801 * failure, but we need to clean up after 802 * xenvif_init_queue() here, and also clean up any 803 * previously initialised queues. 804 */ 805 xenvif_deinit_queue(queue); 806 be->vif->num_queues = queue_index; 807 goto err; 808 } 809 } 810 811#ifdef CONFIG_DEBUG_FS 812 xenvif_debugfs_addif(be->vif); 813#endif /* CONFIG_DEBUG_FS */ 814 815 /* Initialisation completed, tell core driver the number of 816 * active queues. 817 */ 818 rtnl_lock(); 819 netif_set_real_num_tx_queues(be->vif->dev, requested_num_queues); 820 netif_set_real_num_rx_queues(be->vif->dev, requested_num_queues); 821 rtnl_unlock(); 822 823 xenvif_carrier_on(be->vif); 824 825 unregister_hotplug_status_watch(be); 826 err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch, NULL, 827 hotplug_status_changed, 828 "%s/%s", dev->nodename, "hotplug-status"); 829 if (!err) 830 be->have_hotplug_status_watch = 1; 831 832 netif_tx_wake_all_queues(be->vif->dev); 833 834 return; 835 836err: 837 if (be->vif->num_queues > 0) 838 xenvif_disconnect_data(be->vif); /* Clean up existing queues */ 839 for (queue_index = 0; queue_index < be->vif->num_queues; ++queue_index) 840 xenvif_deinit_queue(&be->vif->queues[queue_index]); 841 vfree(be->vif->queues); 842 be->vif->queues = NULL; 843 be->vif->num_queues = 0; 844 xenvif_disconnect_ctrl(be->vif); 845 return; 846} 847 848 849static int connect_data_rings(struct backend_info *be, 850 struct xenvif_queue *queue) 851{ 852 struct xenbus_device *dev = be->dev; 853 unsigned int num_queues = queue->vif->num_queues; 854 unsigned long tx_ring_ref, rx_ring_ref; 855 unsigned int tx_evtchn, rx_evtchn; 856 int err; 857 char *xspath; 858 size_t xspathsize; 859 const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */ 860 861 /* If the frontend requested 1 queue, or we have fallen back 862 * to single queue due to lack of frontend support for multi- 863 * queue, expect the remaining XenStore keys in the toplevel 864 * directory. Otherwise, expect them in a subdirectory called 865 * queue-N. 866 */ 867 if (num_queues == 1) { 868 xspath = kstrdup(dev->otherend, GFP_KERNEL); 869 if (!xspath) { 870 xenbus_dev_fatal(dev, -ENOMEM, 871 "reading ring references"); 872 return -ENOMEM; 873 } 874 } else { 875 xspathsize = strlen(dev->otherend) + xenstore_path_ext_size; 876 xspath = kzalloc(xspathsize, GFP_KERNEL); 877 if (!xspath) { 878 xenbus_dev_fatal(dev, -ENOMEM, 879 "reading ring references"); 880 return -ENOMEM; 881 } 882 snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend, 883 queue->id); 884 } 885 886 err = xenbus_gather(XBT_NIL, xspath, 887 "tx-ring-ref", "%lu", &tx_ring_ref, 888 "rx-ring-ref", "%lu", &rx_ring_ref, NULL); 889 if (err) { 890 xenbus_dev_fatal(dev, err, 891 "reading %s/ring-ref", 892 xspath); 893 goto err; 894 } 895 896 /* Try split event channels first, then single event channel. */ 897 err = xenbus_gather(XBT_NIL, xspath, 898 "event-channel-tx", "%u", &tx_evtchn, 899 "event-channel-rx", "%u", &rx_evtchn, NULL); 900 if (err < 0) { 901 err = xenbus_scanf(XBT_NIL, xspath, 902 "event-channel", "%u", &tx_evtchn); 903 if (err < 0) { 904 xenbus_dev_fatal(dev, err, 905 "reading %s/event-channel(-tx/rx)", 906 xspath); 907 goto err; 908 } 909 rx_evtchn = tx_evtchn; 910 } 911 912 /* Map the shared frame, irq etc. */ 913 err = xenvif_connect_data(queue, tx_ring_ref, rx_ring_ref, 914 tx_evtchn, rx_evtchn); 915 if (err) { 916 xenbus_dev_fatal(dev, err, 917 "mapping shared-frames %lu/%lu port tx %u rx %u", 918 tx_ring_ref, rx_ring_ref, 919 tx_evtchn, rx_evtchn); 920 goto err; 921 } 922 923 err = 0; 924err: /* Regular return falls through with err == 0 */ 925 kfree(xspath); 926 return err; 927} 928 929static int read_xenbus_vif_flags(struct backend_info *be) 930{ 931 struct xenvif *vif = be->vif; 932 struct xenbus_device *dev = be->dev; 933 unsigned int rx_copy; 934 int err; 935 936 err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u", 937 &rx_copy); 938 if (err == -ENOENT) { 939 err = 0; 940 rx_copy = 0; 941 } 942 if (err < 0) { 943 xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy", 944 dev->otherend); 945 return err; 946 } 947 if (!rx_copy) 948 return -EOPNOTSUPP; 949 950 if (!xenbus_read_unsigned(dev->otherend, "feature-rx-notify", 0)) { 951 /* - Reduce drain timeout to poll more frequently for 952 * Rx requests. 953 * - Disable Rx stall detection. 954 */ 955 be->vif->drain_timeout = msecs_to_jiffies(30); 956 be->vif->stall_timeout = 0; 957 } 958 959 vif->can_sg = !!xenbus_read_unsigned(dev->otherend, "feature-sg", 0); 960 961 vif->gso_mask = 0; 962 963 if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv4", 0)) 964 vif->gso_mask |= GSO_BIT(TCPV4); 965 966 if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv6", 0)) 967 vif->gso_mask |= GSO_BIT(TCPV6); 968 969 vif->ip_csum = !xenbus_read_unsigned(dev->otherend, 970 "feature-no-csum-offload", 0); 971 972 vif->ipv6_csum = !!xenbus_read_unsigned(dev->otherend, 973 "feature-ipv6-csum-offload", 0); 974 975 read_xenbus_frontend_xdp(be, dev); 976 977 return 0; 978} 979 980static void netback_remove(struct xenbus_device *dev) 981{ 982 struct backend_info *be = dev_get_drvdata(&dev->dev); 983 984 unregister_hotplug_status_watch(be); 985 xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status"); 986 if (be->vif) { 987 kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE); 988 backend_disconnect(be); 989 xenvif_free(be->vif); 990 be->vif = NULL; 991 } 992 kfree(be->hotplug_script); 993 kfree(be); 994 dev_set_drvdata(&dev->dev, NULL); 995} 996 997/* 998 * Entry point to this code when a new device is created. Allocate the basic 999 * structures and switch to InitWait. 1000 */ 1001static int netback_probe(struct xenbus_device *dev, 1002 const struct xenbus_device_id *id) 1003{ 1004 const char *message; 1005 struct xenbus_transaction xbt; 1006 int err; 1007 int sg; 1008 const char *script; 1009 struct backend_info *be = kzalloc(sizeof(*be), GFP_KERNEL); 1010 1011 if (!be) { 1012 xenbus_dev_fatal(dev, -ENOMEM, 1013 "allocating backend structure"); 1014 return -ENOMEM; 1015 } 1016 1017 be->dev = dev; 1018 dev_set_drvdata(&dev->dev, be); 1019 1020 sg = 1; 1021 1022 do { 1023 err = xenbus_transaction_start(&xbt); 1024 if (err) { 1025 xenbus_dev_fatal(dev, err, "starting transaction"); 1026 goto fail; 1027 } 1028 1029 err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", sg); 1030 if (err) { 1031 message = "writing feature-sg"; 1032 goto abort_transaction; 1033 } 1034 1035 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", 1036 "%d", sg); 1037 if (err) { 1038 message = "writing feature-gso-tcpv4"; 1039 goto abort_transaction; 1040 } 1041 1042 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv6", 1043 "%d", sg); 1044 if (err) { 1045 message = "writing feature-gso-tcpv6"; 1046 goto abort_transaction; 1047 } 1048 1049 /* We support partial checksum setup for IPv6 packets */ 1050 err = xenbus_printf(xbt, dev->nodename, 1051 "feature-ipv6-csum-offload", 1052 "%d", 1); 1053 if (err) { 1054 message = "writing feature-ipv6-csum-offload"; 1055 goto abort_transaction; 1056 } 1057 1058 /* We support rx-copy path. */ 1059 err = xenbus_printf(xbt, dev->nodename, 1060 "feature-rx-copy", "%d", 1); 1061 if (err) { 1062 message = "writing feature-rx-copy"; 1063 goto abort_transaction; 1064 } 1065 1066 /* we can adjust a headroom for netfront XDP processing */ 1067 err = xenbus_printf(xbt, dev->nodename, 1068 "feature-xdp-headroom", "%d", 1069 provides_xdp_headroom); 1070 if (err) { 1071 message = "writing feature-xdp-headroom"; 1072 goto abort_transaction; 1073 } 1074 1075 /* We don't support rx-flip path (except old guests who 1076 * don't grok this feature flag). 1077 */ 1078 err = xenbus_printf(xbt, dev->nodename, 1079 "feature-rx-flip", "%d", 0); 1080 if (err) { 1081 message = "writing feature-rx-flip"; 1082 goto abort_transaction; 1083 } 1084 1085 /* We support dynamic multicast-control. */ 1086 err = xenbus_printf(xbt, dev->nodename, 1087 "feature-multicast-control", "%d", 1); 1088 if (err) { 1089 message = "writing feature-multicast-control"; 1090 goto abort_transaction; 1091 } 1092 1093 err = xenbus_printf(xbt, dev->nodename, 1094 "feature-dynamic-multicast-control", 1095 "%d", 1); 1096 if (err) { 1097 message = "writing feature-dynamic-multicast-control"; 1098 goto abort_transaction; 1099 } 1100 1101 err = xenbus_transaction_end(xbt, 0); 1102 } while (err == -EAGAIN); 1103 1104 if (err) { 1105 xenbus_dev_fatal(dev, err, "completing transaction"); 1106 goto fail; 1107 } 1108 1109 /* Split event channels support, this is optional so it is not 1110 * put inside the above loop. 1111 */ 1112 err = xenbus_printf(XBT_NIL, dev->nodename, 1113 "feature-split-event-channels", 1114 "%u", separate_tx_rx_irq); 1115 if (err) 1116 pr_debug("Error writing feature-split-event-channels\n"); 1117 1118 /* Multi-queue support: This is an optional feature. */ 1119 err = xenbus_printf(XBT_NIL, dev->nodename, 1120 "multi-queue-max-queues", "%u", xenvif_max_queues); 1121 if (err) 1122 pr_debug("Error writing multi-queue-max-queues\n"); 1123 1124 err = xenbus_printf(XBT_NIL, dev->nodename, 1125 "feature-ctrl-ring", 1126 "%u", true); 1127 if (err) 1128 pr_debug("Error writing feature-ctrl-ring\n"); 1129 1130 backend_switch_state(be, XenbusStateInitWait); 1131 1132 script = xenbus_read(XBT_NIL, dev->nodename, "script", NULL); 1133 if (IS_ERR(script)) { 1134 err = PTR_ERR(script); 1135 xenbus_dev_fatal(dev, err, "reading script"); 1136 goto fail; 1137 } 1138 1139 be->hotplug_script = script; 1140 1141 /* This kicks hotplug scripts, so do it immediately. */ 1142 err = backend_create_xenvif(be); 1143 if (err) 1144 goto fail; 1145 1146 return 0; 1147 1148abort_transaction: 1149 xenbus_transaction_end(xbt, 1); 1150 xenbus_dev_fatal(dev, err, "%s", message); 1151fail: 1152 pr_debug("failed\n"); 1153 netback_remove(dev); 1154 return err; 1155} 1156 1157static const struct xenbus_device_id netback_ids[] = { 1158 { "vif" }, 1159 { "" } 1160}; 1161 1162static struct xenbus_driver netback_driver = { 1163 .ids = netback_ids, 1164 .probe = netback_probe, 1165 .remove = netback_remove, 1166 .uevent = netback_uevent, 1167 .otherend_changed = frontend_changed, 1168 .allow_rebind = true, 1169}; 1170 1171int xenvif_xenbus_init(void) 1172{ 1173 return xenbus_register_backend(&netback_driver); 1174} 1175 1176void xenvif_xenbus_fini(void) 1177{ 1178 return xenbus_unregister_driver(&netback_driver); 1179} 1180