1 /* 2 * Virtual network driver for conversing with remote driver backends. 3 * 4 * Copyright (c) 2002-2005, K A Fraser 5 * Copyright (c) 2005, XenSource Ltd 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License version 2 9 * as published by the Free Software Foundation; or, when distributed 10 * separately from the Linux kernel or incorporated into other 11 * software packages, subject to the following license: 12 * 13 * Permission is hereby granted, free of charge, to any person obtaining a copy 14 * of this source file (the "Software"), to deal in the Software without 15 * restriction, including without limitation the rights to use, copy, modify, 16 * merge, publish, distribute, sublicense, and/or sell copies of the Software, 17 * and to permit persons to whom the Software is furnished to do so, subject to 18 * the following conditions: 19 * 20 * The above copyright notice and this permission notice shall be included in 21 * all copies or substantial portions of the Software. 22 * 23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 24 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 25 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 26 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 27 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 28 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 29 * IN THE SOFTWARE. 30 */ 31 32 #include <linux/module.h> 33 #include <linux/kernel.h> 34 #include <linux/netdevice.h> 35 #include <linux/etherdevice.h> 36 #include <linux/skbuff.h> 37 #include <linux/ethtool.h> 38 #include <linux/if_ether.h> 39 #include <linux/tcp.h> 40 #include <linux/udp.h> 41 #include <linux/moduleparam.h> 42 #include <linux/mm.h> 43 #include <linux/slab.h> 44 #include <net/ip.h> 45 46 #include <xen/xen.h> 47 #include <xen/xenbus.h> 48 #include <xen/events.h> 49 #include <xen/page.h> 50 #include <xen/grant_table.h> 51 52 #include <xen/interface/io/netif.h> 53 #include <xen/interface/memory.h> 54 #include <xen/interface/grant_table.h> 55 56 static const struct ethtool_ops xennet_ethtool_ops; 57 58 struct netfront_cb { 59 struct page *page; 60 unsigned offset; 61 }; 62 63 #define NETFRONT_SKB_CB(skb) ((struct netfront_cb *)((skb)->cb)) 64 65 #define RX_COPY_THRESHOLD 256 66 67 #define GRANT_INVALID_REF 0 68 69 #define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE) 70 #define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE) 71 #define TX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256) 72 73 struct netfront_stats { 74 u64 rx_packets; 75 u64 tx_packets; 76 u64 rx_bytes; 77 u64 tx_bytes; 78 struct u64_stats_sync syncp; 79 }; 80 81 struct netfront_info { 82 struct list_head list; 83 struct net_device *netdev; 84 85 struct napi_struct napi; 86 87 unsigned int evtchn; 88 struct xenbus_device *xbdev; 89 90 spinlock_t tx_lock; 91 struct xen_netif_tx_front_ring tx; 92 int tx_ring_ref; 93 94 /* 95 * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries 96 * are linked from tx_skb_freelist through skb_entry.link. 97 * 98 * NB. Freelist index entries are always going to be less than 99 * PAGE_OFFSET, whereas pointers to skbs will always be equal or 100 * greater than PAGE_OFFSET: we use this property to distinguish 101 * them. 102 */ 103 union skb_entry { 104 struct sk_buff *skb; 105 unsigned long link; 106 } tx_skbs[NET_TX_RING_SIZE]; 107 grant_ref_t gref_tx_head; 108 grant_ref_t grant_tx_ref[NET_TX_RING_SIZE]; 109 unsigned tx_skb_freelist; 110 111 spinlock_t rx_lock ____cacheline_aligned_in_smp; 112 struct xen_netif_rx_front_ring rx; 113 int rx_ring_ref; 114 115 /* Receive-ring batched refills. */ 116 #define RX_MIN_TARGET 8 117 #define RX_DFL_MIN_TARGET 64 118 #define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256) 119 unsigned rx_min_target, rx_max_target, rx_target; 120 struct sk_buff_head rx_batch; 121 122 struct timer_list rx_refill_timer; 123 124 struct sk_buff *rx_skbs[NET_RX_RING_SIZE]; 125 grant_ref_t gref_rx_head; 126 grant_ref_t grant_rx_ref[NET_RX_RING_SIZE]; 127 128 unsigned long rx_pfn_array[NET_RX_RING_SIZE]; 129 struct multicall_entry rx_mcl[NET_RX_RING_SIZE+1]; 130 struct mmu_update rx_mmu[NET_RX_RING_SIZE]; 131 132 /* Statistics */ 133 struct netfront_stats __percpu *stats; 134 135 unsigned long rx_gso_checksum_fixup; 136 }; 137 138 struct netfront_rx_info { 139 struct xen_netif_rx_response rx; 140 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1]; 141 }; 142 143 static void skb_entry_set_link(union skb_entry *list, unsigned short id) 144 { 145 list->link = id; 146 } 147 148 static int skb_entry_is_link(const union skb_entry *list) 149 { 150 BUILD_BUG_ON(sizeof(list->skb) != sizeof(list->link)); 151 return (unsigned long)list->skb < PAGE_OFFSET; 152 } 153 154 /* 155 * Access macros for acquiring freeing slots in tx_skbs[]. 156 */ 157 158 static void add_id_to_freelist(unsigned *head, union skb_entry *list, 159 unsigned short id) 160 { 161 skb_entry_set_link(&list[id], *head); 162 *head = id; 163 } 164 165 static unsigned short get_id_from_freelist(unsigned *head, 166 union skb_entry *list) 167 { 168 unsigned int id = *head; 169 *head = list[id].link; 170 return id; 171 } 172 173 static int xennet_rxidx(RING_IDX idx) 174 { 175 return idx & (NET_RX_RING_SIZE - 1); 176 } 177 178 static struct sk_buff *xennet_get_rx_skb(struct netfront_info *np, 179 RING_IDX ri) 180 { 181 int i = xennet_rxidx(ri); 182 struct sk_buff *skb = np->rx_skbs[i]; 183 np->rx_skbs[i] = NULL; 184 return skb; 185 } 186 187 static grant_ref_t xennet_get_rx_ref(struct netfront_info *np, 188 RING_IDX ri) 189 { 190 int i = xennet_rxidx(ri); 191 grant_ref_t ref = np->grant_rx_ref[i]; 192 np->grant_rx_ref[i] = GRANT_INVALID_REF; 193 return ref; 194 } 195 196 #ifdef CONFIG_SYSFS 197 static int xennet_sysfs_addif(struct net_device *netdev); 198 static void xennet_sysfs_delif(struct net_device *netdev); 199 #else /* !CONFIG_SYSFS */ 200 #define xennet_sysfs_addif(dev) (0) 201 #define xennet_sysfs_delif(dev) do { } while (0) 202 #endif 203 204 static int xennet_can_sg(struct net_device *dev) 205 { 206 return dev->features & NETIF_F_SG; 207 } 208 209 210 static void rx_refill_timeout(unsigned long data) 211 { 212 struct net_device *dev = (struct net_device *)data; 213 struct netfront_info *np = netdev_priv(dev); 214 napi_schedule(&np->napi); 215 } 216 217 static int netfront_tx_slot_available(struct netfront_info *np) 218 { 219 return (np->tx.req_prod_pvt - np->tx.rsp_cons) < 220 (TX_MAX_TARGET - MAX_SKB_FRAGS - 2); 221 } 222 223 static void xennet_maybe_wake_tx(struct net_device *dev) 224 { 225 struct netfront_info *np = netdev_priv(dev); 226 227 if (unlikely(netif_queue_stopped(dev)) && 228 netfront_tx_slot_available(np) && 229 likely(netif_running(dev))) 230 netif_wake_queue(dev); 231 } 232 233 static void xennet_alloc_rx_buffers(struct net_device *dev) 234 { 235 unsigned short id; 236 struct netfront_info *np = netdev_priv(dev); 237 struct sk_buff *skb; 238 struct page *page; 239 int i, batch_target, notify; 240 RING_IDX req_prod = np->rx.req_prod_pvt; 241 grant_ref_t ref; 242 unsigned long pfn; 243 void *vaddr; 244 struct xen_netif_rx_request *req; 245 246 if (unlikely(!netif_carrier_ok(dev))) 247 return; 248 249 /* 250 * Allocate skbuffs greedily, even though we batch updates to the 251 * receive ring. This creates a less bursty demand on the memory 252 * allocator, so should reduce the chance of failed allocation requests 253 * both for ourself and for other kernel subsystems. 254 */ 255 batch_target = np->rx_target - (req_prod - np->rx.rsp_cons); 256 for (i = skb_queue_len(&np->rx_batch); i < batch_target; i++) { 257 skb = __netdev_alloc_skb(dev, RX_COPY_THRESHOLD + NET_IP_ALIGN, 258 GFP_ATOMIC | __GFP_NOWARN); 259 if (unlikely(!skb)) 260 goto no_skb; 261 262 /* Align ip header to a 16 bytes boundary */ 263 skb_reserve(skb, NET_IP_ALIGN); 264 265 page = alloc_page(GFP_ATOMIC | __GFP_NOWARN); 266 if (!page) { 267 kfree_skb(skb); 268 no_skb: 269 /* Any skbuffs queued for refill? Force them out. */ 270 if (i != 0) 271 goto refill; 272 /* Could not allocate any skbuffs. Try again later. */ 273 mod_timer(&np->rx_refill_timer, 274 jiffies + (HZ/10)); 275 break; 276 } 277 278 skb_shinfo(skb)->frags[0].page = page; 279 skb_shinfo(skb)->nr_frags = 1; 280 __skb_queue_tail(&np->rx_batch, skb); 281 } 282 283 /* Is the batch large enough to be worthwhile? */ 284 if (i < (np->rx_target/2)) { 285 if (req_prod > np->rx.sring->req_prod) 286 goto push; 287 return; 288 } 289 290 /* Adjust our fill target if we risked running out of buffers. */ 291 if (((req_prod - np->rx.sring->rsp_prod) < (np->rx_target / 4)) && 292 ((np->rx_target *= 2) > np->rx_max_target)) 293 np->rx_target = np->rx_max_target; 294 295 refill: 296 for (i = 0; ; i++) { 297 skb = __skb_dequeue(&np->rx_batch); 298 if (skb == NULL) 299 break; 300 301 skb->dev = dev; 302 303 id = xennet_rxidx(req_prod + i); 304 305 BUG_ON(np->rx_skbs[id]); 306 np->rx_skbs[id] = skb; 307 308 ref = gnttab_claim_grant_reference(&np->gref_rx_head); 309 BUG_ON((signed short)ref < 0); 310 np->grant_rx_ref[id] = ref; 311 312 pfn = page_to_pfn(skb_shinfo(skb)->frags[0].page); 313 vaddr = page_address(skb_shinfo(skb)->frags[0].page); 314 315 req = RING_GET_REQUEST(&np->rx, req_prod + i); 316 gnttab_grant_foreign_access_ref(ref, 317 np->xbdev->otherend_id, 318 pfn_to_mfn(pfn), 319 0); 320 321 req->id = id; 322 req->gref = ref; 323 } 324 325 wmb(); /* barrier so backend seens requests */ 326 327 /* Above is a suitable barrier to ensure backend will see requests. */ 328 np->rx.req_prod_pvt = req_prod + i; 329 push: 330 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->rx, notify); 331 if (notify) 332 notify_remote_via_irq(np->netdev->irq); 333 } 334 335 static int xennet_open(struct net_device *dev) 336 { 337 struct netfront_info *np = netdev_priv(dev); 338 339 napi_enable(&np->napi); 340 341 spin_lock_bh(&np->rx_lock); 342 if (netif_carrier_ok(dev)) { 343 xennet_alloc_rx_buffers(dev); 344 np->rx.sring->rsp_event = np->rx.rsp_cons + 1; 345 if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx)) 346 napi_schedule(&np->napi); 347 } 348 spin_unlock_bh(&np->rx_lock); 349 350 netif_start_queue(dev); 351 352 return 0; 353 } 354 355 static void xennet_tx_buf_gc(struct net_device *dev) 356 { 357 RING_IDX cons, prod; 358 unsigned short id; 359 struct netfront_info *np = netdev_priv(dev); 360 struct sk_buff *skb; 361 362 BUG_ON(!netif_carrier_ok(dev)); 363 364 do { 365 prod = np->tx.sring->rsp_prod; 366 rmb(); /* Ensure we see responses up to 'rp'. */ 367 368 for (cons = np->tx.rsp_cons; cons != prod; cons++) { 369 struct xen_netif_tx_response *txrsp; 370 371 txrsp = RING_GET_RESPONSE(&np->tx, cons); 372 if (txrsp->status == XEN_NETIF_RSP_NULL) 373 continue; 374 375 id = txrsp->id; 376 skb = np->tx_skbs[id].skb; 377 if (unlikely(gnttab_query_foreign_access( 378 np->grant_tx_ref[id]) != 0)) { 379 printk(KERN_ALERT "xennet_tx_buf_gc: warning " 380 "-- grant still in use by backend " 381 "domain.\n"); 382 BUG(); 383 } 384 gnttab_end_foreign_access_ref( 385 np->grant_tx_ref[id], GNTMAP_readonly); 386 gnttab_release_grant_reference( 387 &np->gref_tx_head, np->grant_tx_ref[id]); 388 np->grant_tx_ref[id] = GRANT_INVALID_REF; 389 add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, id); 390 dev_kfree_skb_irq(skb); 391 } 392 393 np->tx.rsp_cons = prod; 394 395 /* 396 * Set a new event, then check for race with update of tx_cons. 397 * Note that it is essential to schedule a callback, no matter 398 * how few buffers are pending. Even if there is space in the 399 * transmit ring, higher layers may be blocked because too much 400 * data is outstanding: in such cases notification from Xen is 401 * likely to be the only kick that we'll get. 402 */ 403 np->tx.sring->rsp_event = 404 prod + ((np->tx.sring->req_prod - prod) >> 1) + 1; 405 mb(); /* update shared area */ 406 } while ((cons == prod) && (prod != np->tx.sring->rsp_prod)); 407 408 xennet_maybe_wake_tx(dev); 409 } 410 411 static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev, 412 struct xen_netif_tx_request *tx) 413 { 414 struct netfront_info *np = netdev_priv(dev); 415 char *data = skb->data; 416 unsigned long mfn; 417 RING_IDX prod = np->tx.req_prod_pvt; 418 int frags = skb_shinfo(skb)->nr_frags; 419 unsigned int offset = offset_in_page(data); 420 unsigned int len = skb_headlen(skb); 421 unsigned int id; 422 grant_ref_t ref; 423 int i; 424 425 /* While the header overlaps a page boundary (including being 426 larger than a page), split it it into page-sized chunks. */ 427 while (len > PAGE_SIZE - offset) { 428 tx->size = PAGE_SIZE - offset; 429 tx->flags |= XEN_NETTXF_more_data; 430 len -= tx->size; 431 data += tx->size; 432 offset = 0; 433 434 id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs); 435 np->tx_skbs[id].skb = skb_get(skb); 436 tx = RING_GET_REQUEST(&np->tx, prod++); 437 tx->id = id; 438 ref = gnttab_claim_grant_reference(&np->gref_tx_head); 439 BUG_ON((signed short)ref < 0); 440 441 mfn = virt_to_mfn(data); 442 gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id, 443 mfn, GNTMAP_readonly); 444 445 tx->gref = np->grant_tx_ref[id] = ref; 446 tx->offset = offset; 447 tx->size = len; 448 tx->flags = 0; 449 } 450 451 /* Grant backend access to each skb fragment page. */ 452 for (i = 0; i < frags; i++) { 453 skb_frag_t *frag = skb_shinfo(skb)->frags + i; 454 455 tx->flags |= XEN_NETTXF_more_data; 456 457 id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs); 458 np->tx_skbs[id].skb = skb_get(skb); 459 tx = RING_GET_REQUEST(&np->tx, prod++); 460 tx->id = id; 461 ref = gnttab_claim_grant_reference(&np->gref_tx_head); 462 BUG_ON((signed short)ref < 0); 463 464 mfn = pfn_to_mfn(page_to_pfn(frag->page)); 465 gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id, 466 mfn, GNTMAP_readonly); 467 468 tx->gref = np->grant_tx_ref[id] = ref; 469 tx->offset = frag->page_offset; 470 tx->size = frag->size; 471 tx->flags = 0; 472 } 473 474 np->tx.req_prod_pvt = prod; 475 } 476 477 static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev) 478 { 479 unsigned short id; 480 struct netfront_info *np = netdev_priv(dev); 481 struct netfront_stats *stats = this_cpu_ptr(np->stats); 482 struct xen_netif_tx_request *tx; 483 struct xen_netif_extra_info *extra; 484 char *data = skb->data; 485 RING_IDX i; 486 grant_ref_t ref; 487 unsigned long mfn; 488 int notify; 489 int frags = skb_shinfo(skb)->nr_frags; 490 unsigned int offset = offset_in_page(data); 491 unsigned int len = skb_headlen(skb); 492 493 frags += DIV_ROUND_UP(offset + len, PAGE_SIZE); 494 if (unlikely(frags > MAX_SKB_FRAGS + 1)) { 495 printk(KERN_ALERT "xennet: skb rides the rocket: %d frags\n", 496 frags); 497 dump_stack(); 498 goto drop; 499 } 500 501 spin_lock_irq(&np->tx_lock); 502 503 if (unlikely(!netif_carrier_ok(dev) || 504 (frags > 1 && !xennet_can_sg(dev)) || 505 netif_needs_gso(skb, netif_skb_features(skb)))) { 506 spin_unlock_irq(&np->tx_lock); 507 goto drop; 508 } 509 510 i = np->tx.req_prod_pvt; 511 512 id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs); 513 np->tx_skbs[id].skb = skb; 514 515 tx = RING_GET_REQUEST(&np->tx, i); 516 517 tx->id = id; 518 ref = gnttab_claim_grant_reference(&np->gref_tx_head); 519 BUG_ON((signed short)ref < 0); 520 mfn = virt_to_mfn(data); 521 gnttab_grant_foreign_access_ref( 522 ref, np->xbdev->otherend_id, mfn, GNTMAP_readonly); 523 tx->gref = np->grant_tx_ref[id] = ref; 524 tx->offset = offset; 525 tx->size = len; 526 extra = NULL; 527 528 tx->flags = 0; 529 if (skb->ip_summed == CHECKSUM_PARTIAL) 530 /* local packet? */ 531 tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated; 532 else if (skb->ip_summed == CHECKSUM_UNNECESSARY) 533 /* remote but checksummed. */ 534 tx->flags |= XEN_NETTXF_data_validated; 535 536 if (skb_shinfo(skb)->gso_size) { 537 struct xen_netif_extra_info *gso; 538 539 gso = (struct xen_netif_extra_info *) 540 RING_GET_REQUEST(&np->tx, ++i); 541 542 if (extra) 543 extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE; 544 else 545 tx->flags |= XEN_NETTXF_extra_info; 546 547 gso->u.gso.size = skb_shinfo(skb)->gso_size; 548 gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4; 549 gso->u.gso.pad = 0; 550 gso->u.gso.features = 0; 551 552 gso->type = XEN_NETIF_EXTRA_TYPE_GSO; 553 gso->flags = 0; 554 extra = gso; 555 } 556 557 np->tx.req_prod_pvt = i + 1; 558 559 xennet_make_frags(skb, dev, tx); 560 tx->size = skb->len; 561 562 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->tx, notify); 563 if (notify) 564 notify_remote_via_irq(np->netdev->irq); 565 566 u64_stats_update_begin(&stats->syncp); 567 stats->tx_bytes += skb->len; 568 stats->tx_packets++; 569 u64_stats_update_end(&stats->syncp); 570 571 /* Note: It is not safe to access skb after xennet_tx_buf_gc()! */ 572 xennet_tx_buf_gc(dev); 573 574 if (!netfront_tx_slot_available(np)) 575 netif_stop_queue(dev); 576 577 spin_unlock_irq(&np->tx_lock); 578 579 return NETDEV_TX_OK; 580 581 drop: 582 dev->stats.tx_dropped++; 583 dev_kfree_skb(skb); 584 return NETDEV_TX_OK; 585 } 586 587 static int xennet_close(struct net_device *dev) 588 { 589 struct netfront_info *np = netdev_priv(dev); 590 netif_stop_queue(np->netdev); 591 napi_disable(&np->napi); 592 return 0; 593 } 594 595 static void xennet_move_rx_slot(struct netfront_info *np, struct sk_buff *skb, 596 grant_ref_t ref) 597 { 598 int new = xennet_rxidx(np->rx.req_prod_pvt); 599 600 BUG_ON(np->rx_skbs[new]); 601 np->rx_skbs[new] = skb; 602 np->grant_rx_ref[new] = ref; 603 RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->id = new; 604 RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->gref = ref; 605 np->rx.req_prod_pvt++; 606 } 607 608 static int xennet_get_extras(struct netfront_info *np, 609 struct xen_netif_extra_info *extras, 610 RING_IDX rp) 611 612 { 613 struct xen_netif_extra_info *extra; 614 struct device *dev = &np->netdev->dev; 615 RING_IDX cons = np->rx.rsp_cons; 616 int err = 0; 617 618 do { 619 struct sk_buff *skb; 620 grant_ref_t ref; 621 622 if (unlikely(cons + 1 == rp)) { 623 if (net_ratelimit()) 624 dev_warn(dev, "Missing extra info\n"); 625 err = -EBADR; 626 break; 627 } 628 629 extra = (struct xen_netif_extra_info *) 630 RING_GET_RESPONSE(&np->rx, ++cons); 631 632 if (unlikely(!extra->type || 633 extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) { 634 if (net_ratelimit()) 635 dev_warn(dev, "Invalid extra type: %d\n", 636 extra->type); 637 err = -EINVAL; 638 } else { 639 memcpy(&extras[extra->type - 1], extra, 640 sizeof(*extra)); 641 } 642 643 skb = xennet_get_rx_skb(np, cons); 644 ref = xennet_get_rx_ref(np, cons); 645 xennet_move_rx_slot(np, skb, ref); 646 } while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE); 647 648 np->rx.rsp_cons = cons; 649 return err; 650 } 651 652 static int xennet_get_responses(struct netfront_info *np, 653 struct netfront_rx_info *rinfo, RING_IDX rp, 654 struct sk_buff_head *list) 655 { 656 struct xen_netif_rx_response *rx = &rinfo->rx; 657 struct xen_netif_extra_info *extras = rinfo->extras; 658 struct device *dev = &np->netdev->dev; 659 RING_IDX cons = np->rx.rsp_cons; 660 struct sk_buff *skb = xennet_get_rx_skb(np, cons); 661 grant_ref_t ref = xennet_get_rx_ref(np, cons); 662 int max = MAX_SKB_FRAGS + (rx->status <= RX_COPY_THRESHOLD); 663 int frags = 1; 664 int err = 0; 665 unsigned long ret; 666 667 if (rx->flags & XEN_NETRXF_extra_info) { 668 err = xennet_get_extras(np, extras, rp); 669 cons = np->rx.rsp_cons; 670 } 671 672 for (;;) { 673 if (unlikely(rx->status < 0 || 674 rx->offset + rx->status > PAGE_SIZE)) { 675 if (net_ratelimit()) 676 dev_warn(dev, "rx->offset: %x, size: %u\n", 677 rx->offset, rx->status); 678 xennet_move_rx_slot(np, skb, ref); 679 err = -EINVAL; 680 goto next; 681 } 682 683 /* 684 * This definitely indicates a bug, either in this driver or in 685 * the backend driver. In future this should flag the bad 686 * situation to the system controller to reboot the backed. 687 */ 688 if (ref == GRANT_INVALID_REF) { 689 if (net_ratelimit()) 690 dev_warn(dev, "Bad rx response id %d.\n", 691 rx->id); 692 err = -EINVAL; 693 goto next; 694 } 695 696 ret = gnttab_end_foreign_access_ref(ref, 0); 697 BUG_ON(!ret); 698 699 gnttab_release_grant_reference(&np->gref_rx_head, ref); 700 701 __skb_queue_tail(list, skb); 702 703 next: 704 if (!(rx->flags & XEN_NETRXF_more_data)) 705 break; 706 707 if (cons + frags == rp) { 708 if (net_ratelimit()) 709 dev_warn(dev, "Need more frags\n"); 710 err = -ENOENT; 711 break; 712 } 713 714 rx = RING_GET_RESPONSE(&np->rx, cons + frags); 715 skb = xennet_get_rx_skb(np, cons + frags); 716 ref = xennet_get_rx_ref(np, cons + frags); 717 frags++; 718 } 719 720 if (unlikely(frags > max)) { 721 if (net_ratelimit()) 722 dev_warn(dev, "Too many frags\n"); 723 err = -E2BIG; 724 } 725 726 if (unlikely(err)) 727 np->rx.rsp_cons = cons + frags; 728 729 return err; 730 } 731 732 static int xennet_set_skb_gso(struct sk_buff *skb, 733 struct xen_netif_extra_info *gso) 734 { 735 if (!gso->u.gso.size) { 736 if (net_ratelimit()) 737 printk(KERN_WARNING "GSO size must not be zero.\n"); 738 return -EINVAL; 739 } 740 741 /* Currently only TCPv4 S.O. is supported. */ 742 if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) { 743 if (net_ratelimit()) 744 printk(KERN_WARNING "Bad GSO type %d.\n", gso->u.gso.type); 745 return -EINVAL; 746 } 747 748 skb_shinfo(skb)->gso_size = gso->u.gso.size; 749 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 750 751 /* Header must be checked, and gso_segs computed. */ 752 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 753 skb_shinfo(skb)->gso_segs = 0; 754 755 return 0; 756 } 757 758 static RING_IDX xennet_fill_frags(struct netfront_info *np, 759 struct sk_buff *skb, 760 struct sk_buff_head *list) 761 { 762 struct skb_shared_info *shinfo = skb_shinfo(skb); 763 int nr_frags = shinfo->nr_frags; 764 RING_IDX cons = np->rx.rsp_cons; 765 skb_frag_t *frag = shinfo->frags + nr_frags; 766 struct sk_buff *nskb; 767 768 while ((nskb = __skb_dequeue(list))) { 769 struct xen_netif_rx_response *rx = 770 RING_GET_RESPONSE(&np->rx, ++cons); 771 772 frag->page = skb_shinfo(nskb)->frags[0].page; 773 frag->page_offset = rx->offset; 774 frag->size = rx->status; 775 776 skb->data_len += rx->status; 777 778 skb_shinfo(nskb)->nr_frags = 0; 779 kfree_skb(nskb); 780 781 frag++; 782 nr_frags++; 783 } 784 785 shinfo->nr_frags = nr_frags; 786 return cons; 787 } 788 789 static int checksum_setup(struct net_device *dev, struct sk_buff *skb) 790 { 791 struct iphdr *iph; 792 unsigned char *th; 793 int err = -EPROTO; 794 int recalculate_partial_csum = 0; 795 796 /* 797 * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy 798 * peers can fail to set NETRXF_csum_blank when sending a GSO 799 * frame. In this case force the SKB to CHECKSUM_PARTIAL and 800 * recalculate the partial checksum. 801 */ 802 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) { 803 struct netfront_info *np = netdev_priv(dev); 804 np->rx_gso_checksum_fixup++; 805 skb->ip_summed = CHECKSUM_PARTIAL; 806 recalculate_partial_csum = 1; 807 } 808 809 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */ 810 if (skb->ip_summed != CHECKSUM_PARTIAL) 811 return 0; 812 813 if (skb->protocol != htons(ETH_P_IP)) 814 goto out; 815 816 iph = (void *)skb->data; 817 th = skb->data + 4 * iph->ihl; 818 if (th >= skb_tail_pointer(skb)) 819 goto out; 820 821 skb->csum_start = th - skb->head; 822 switch (iph->protocol) { 823 case IPPROTO_TCP: 824 skb->csum_offset = offsetof(struct tcphdr, check); 825 826 if (recalculate_partial_csum) { 827 struct tcphdr *tcph = (struct tcphdr *)th; 828 tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, 829 skb->len - iph->ihl*4, 830 IPPROTO_TCP, 0); 831 } 832 break; 833 case IPPROTO_UDP: 834 skb->csum_offset = offsetof(struct udphdr, check); 835 836 if (recalculate_partial_csum) { 837 struct udphdr *udph = (struct udphdr *)th; 838 udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, 839 skb->len - iph->ihl*4, 840 IPPROTO_UDP, 0); 841 } 842 break; 843 default: 844 if (net_ratelimit()) 845 printk(KERN_ERR "Attempting to checksum a non-" 846 "TCP/UDP packet, dropping a protocol" 847 " %d packet", iph->protocol); 848 goto out; 849 } 850 851 if ((th + skb->csum_offset + 2) > skb_tail_pointer(skb)) 852 goto out; 853 854 err = 0; 855 856 out: 857 return err; 858 } 859 860 static int handle_incoming_queue(struct net_device *dev, 861 struct sk_buff_head *rxq) 862 { 863 struct netfront_info *np = netdev_priv(dev); 864 struct netfront_stats *stats = this_cpu_ptr(np->stats); 865 int packets_dropped = 0; 866 struct sk_buff *skb; 867 868 while ((skb = __skb_dequeue(rxq)) != NULL) { 869 struct page *page = NETFRONT_SKB_CB(skb)->page; 870 void *vaddr = page_address(page); 871 unsigned offset = NETFRONT_SKB_CB(skb)->offset; 872 873 memcpy(skb->data, vaddr + offset, 874 skb_headlen(skb)); 875 876 if (page != skb_shinfo(skb)->frags[0].page) 877 __free_page(page); 878 879 /* Ethernet work: Delayed to here as it peeks the header. */ 880 skb->protocol = eth_type_trans(skb, dev); 881 882 if (checksum_setup(dev, skb)) { 883 kfree_skb(skb); 884 packets_dropped++; 885 dev->stats.rx_errors++; 886 continue; 887 } 888 889 u64_stats_update_begin(&stats->syncp); 890 stats->rx_packets++; 891 stats->rx_bytes += skb->len; 892 u64_stats_update_end(&stats->syncp); 893 894 /* Pass it up. */ 895 netif_receive_skb(skb); 896 } 897 898 return packets_dropped; 899 } 900 901 static int xennet_poll(struct napi_struct *napi, int budget) 902 { 903 struct netfront_info *np = container_of(napi, struct netfront_info, napi); 904 struct net_device *dev = np->netdev; 905 struct sk_buff *skb; 906 struct netfront_rx_info rinfo; 907 struct xen_netif_rx_response *rx = &rinfo.rx; 908 struct xen_netif_extra_info *extras = rinfo.extras; 909 RING_IDX i, rp; 910 int work_done; 911 struct sk_buff_head rxq; 912 struct sk_buff_head errq; 913 struct sk_buff_head tmpq; 914 unsigned long flags; 915 unsigned int len; 916 int err; 917 918 spin_lock(&np->rx_lock); 919 920 skb_queue_head_init(&rxq); 921 skb_queue_head_init(&errq); 922 skb_queue_head_init(&tmpq); 923 924 rp = np->rx.sring->rsp_prod; 925 rmb(); /* Ensure we see queued responses up to 'rp'. */ 926 927 i = np->rx.rsp_cons; 928 work_done = 0; 929 while ((i != rp) && (work_done < budget)) { 930 memcpy(rx, RING_GET_RESPONSE(&np->rx, i), sizeof(*rx)); 931 memset(extras, 0, sizeof(rinfo.extras)); 932 933 err = xennet_get_responses(np, &rinfo, rp, &tmpq); 934 935 if (unlikely(err)) { 936 err: 937 while ((skb = __skb_dequeue(&tmpq))) 938 __skb_queue_tail(&errq, skb); 939 dev->stats.rx_errors++; 940 i = np->rx.rsp_cons; 941 continue; 942 } 943 944 skb = __skb_dequeue(&tmpq); 945 946 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) { 947 struct xen_netif_extra_info *gso; 948 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1]; 949 950 if (unlikely(xennet_set_skb_gso(skb, gso))) { 951 __skb_queue_head(&tmpq, skb); 952 np->rx.rsp_cons += skb_queue_len(&tmpq); 953 goto err; 954 } 955 } 956 957 NETFRONT_SKB_CB(skb)->page = skb_shinfo(skb)->frags[0].page; 958 NETFRONT_SKB_CB(skb)->offset = rx->offset; 959 960 len = rx->status; 961 if (len > RX_COPY_THRESHOLD) 962 len = RX_COPY_THRESHOLD; 963 skb_put(skb, len); 964 965 if (rx->status > len) { 966 skb_shinfo(skb)->frags[0].page_offset = 967 rx->offset + len; 968 skb_shinfo(skb)->frags[0].size = rx->status - len; 969 skb->data_len = rx->status - len; 970 } else { 971 skb_shinfo(skb)->frags[0].page = NULL; 972 skb_shinfo(skb)->nr_frags = 0; 973 } 974 975 i = xennet_fill_frags(np, skb, &tmpq); 976 977 /* 978 * Truesize approximates the size of true data plus 979 * any supervisor overheads. Adding hypervisor 980 * overheads has been shown to significantly reduce 981 * achievable bandwidth with the default receive 982 * buffer size. It is therefore not wise to account 983 * for it here. 984 * 985 * After alloc_skb(RX_COPY_THRESHOLD), truesize is set 986 * to RX_COPY_THRESHOLD + the supervisor 987 * overheads. Here, we add the size of the data pulled 988 * in xennet_fill_frags(). 989 * 990 * We also adjust for any unused space in the main 991 * data area by subtracting (RX_COPY_THRESHOLD - 992 * len). This is especially important with drivers 993 * which split incoming packets into header and data, 994 * using only 66 bytes of the main data area (see the 995 * e1000 driver for example.) On such systems, 996 * without this last adjustement, our achievable 997 * receive throughout using the standard receive 998 * buffer size was cut by 25%(!!!). 999 */ 1000 skb->truesize += skb->data_len - (RX_COPY_THRESHOLD - len); 1001 skb->len += skb->data_len; 1002 1003 if (rx->flags & XEN_NETRXF_csum_blank) 1004 skb->ip_summed = CHECKSUM_PARTIAL; 1005 else if (rx->flags & XEN_NETRXF_data_validated) 1006 skb->ip_summed = CHECKSUM_UNNECESSARY; 1007 1008 __skb_queue_tail(&rxq, skb); 1009 1010 np->rx.rsp_cons = ++i; 1011 work_done++; 1012 } 1013 1014 __skb_queue_purge(&errq); 1015 1016 work_done -= handle_incoming_queue(dev, &rxq); 1017 1018 /* If we get a callback with very few responses, reduce fill target. */ 1019 /* NB. Note exponential increase, linear decrease. */ 1020 if (((np->rx.req_prod_pvt - np->rx.sring->rsp_prod) > 1021 ((3*np->rx_target) / 4)) && 1022 (--np->rx_target < np->rx_min_target)) 1023 np->rx_target = np->rx_min_target; 1024 1025 xennet_alloc_rx_buffers(dev); 1026 1027 if (work_done < budget) { 1028 int more_to_do = 0; 1029 1030 local_irq_save(flags); 1031 1032 RING_FINAL_CHECK_FOR_RESPONSES(&np->rx, more_to_do); 1033 if (!more_to_do) 1034 __napi_complete(napi); 1035 1036 local_irq_restore(flags); 1037 } 1038 1039 spin_unlock(&np->rx_lock); 1040 1041 return work_done; 1042 } 1043 1044 static int xennet_change_mtu(struct net_device *dev, int mtu) 1045 { 1046 int max = xennet_can_sg(dev) ? 65535 - ETH_HLEN : ETH_DATA_LEN; 1047 1048 if (mtu > max) 1049 return -EINVAL; 1050 dev->mtu = mtu; 1051 return 0; 1052 } 1053 1054 static struct rtnl_link_stats64 *xennet_get_stats64(struct net_device *dev, 1055 struct rtnl_link_stats64 *tot) 1056 { 1057 struct netfront_info *np = netdev_priv(dev); 1058 int cpu; 1059 1060 for_each_possible_cpu(cpu) { 1061 struct netfront_stats *stats = per_cpu_ptr(np->stats, cpu); 1062 u64 rx_packets, rx_bytes, tx_packets, tx_bytes; 1063 unsigned int start; 1064 1065 do { 1066 start = u64_stats_fetch_begin_bh(&stats->syncp); 1067 1068 rx_packets = stats->rx_packets; 1069 tx_packets = stats->tx_packets; 1070 rx_bytes = stats->rx_bytes; 1071 tx_bytes = stats->tx_bytes; 1072 } while (u64_stats_fetch_retry_bh(&stats->syncp, start)); 1073 1074 tot->rx_packets += rx_packets; 1075 tot->tx_packets += tx_packets; 1076 tot->rx_bytes += rx_bytes; 1077 tot->tx_bytes += tx_bytes; 1078 } 1079 1080 tot->rx_errors = dev->stats.rx_errors; 1081 tot->tx_dropped = dev->stats.tx_dropped; 1082 1083 return tot; 1084 } 1085 1086 static void xennet_release_tx_bufs(struct netfront_info *np) 1087 { 1088 struct sk_buff *skb; 1089 int i; 1090 1091 for (i = 0; i < NET_TX_RING_SIZE; i++) { 1092 /* Skip over entries which are actually freelist references */ 1093 if (skb_entry_is_link(&np->tx_skbs[i])) 1094 continue; 1095 1096 skb = np->tx_skbs[i].skb; 1097 gnttab_end_foreign_access_ref(np->grant_tx_ref[i], 1098 GNTMAP_readonly); 1099 gnttab_release_grant_reference(&np->gref_tx_head, 1100 np->grant_tx_ref[i]); 1101 np->grant_tx_ref[i] = GRANT_INVALID_REF; 1102 add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, i); 1103 dev_kfree_skb_irq(skb); 1104 } 1105 } 1106 1107 static void xennet_release_rx_bufs(struct netfront_info *np) 1108 { 1109 struct mmu_update *mmu = np->rx_mmu; 1110 struct multicall_entry *mcl = np->rx_mcl; 1111 struct sk_buff_head free_list; 1112 struct sk_buff *skb; 1113 unsigned long mfn; 1114 int xfer = 0, noxfer = 0, unused = 0; 1115 int id, ref; 1116 1117 dev_warn(&np->netdev->dev, "%s: fix me for copying receiver.\n", 1118 __func__); 1119 return; 1120 1121 skb_queue_head_init(&free_list); 1122 1123 spin_lock_bh(&np->rx_lock); 1124 1125 for (id = 0; id < NET_RX_RING_SIZE; id++) { 1126 ref = np->grant_rx_ref[id]; 1127 if (ref == GRANT_INVALID_REF) { 1128 unused++; 1129 continue; 1130 } 1131 1132 skb = np->rx_skbs[id]; 1133 mfn = gnttab_end_foreign_transfer_ref(ref); 1134 gnttab_release_grant_reference(&np->gref_rx_head, ref); 1135 np->grant_rx_ref[id] = GRANT_INVALID_REF; 1136 1137 if (0 == mfn) { 1138 skb_shinfo(skb)->nr_frags = 0; 1139 dev_kfree_skb(skb); 1140 noxfer++; 1141 continue; 1142 } 1143 1144 if (!xen_feature(XENFEAT_auto_translated_physmap)) { 1145 /* Remap the page. */ 1146 struct page *page = skb_shinfo(skb)->frags[0].page; 1147 unsigned long pfn = page_to_pfn(page); 1148 void *vaddr = page_address(page); 1149 1150 MULTI_update_va_mapping(mcl, (unsigned long)vaddr, 1151 mfn_pte(mfn, PAGE_KERNEL), 1152 0); 1153 mcl++; 1154 mmu->ptr = ((u64)mfn << PAGE_SHIFT) 1155 | MMU_MACHPHYS_UPDATE; 1156 mmu->val = pfn; 1157 mmu++; 1158 1159 set_phys_to_machine(pfn, mfn); 1160 } 1161 __skb_queue_tail(&free_list, skb); 1162 xfer++; 1163 } 1164 1165 dev_info(&np->netdev->dev, "%s: %d xfer, %d noxfer, %d unused\n", 1166 __func__, xfer, noxfer, unused); 1167 1168 if (xfer) { 1169 if (!xen_feature(XENFEAT_auto_translated_physmap)) { 1170 /* Do all the remapping work and M2P updates. */ 1171 MULTI_mmu_update(mcl, np->rx_mmu, mmu - np->rx_mmu, 1172 NULL, DOMID_SELF); 1173 mcl++; 1174 HYPERVISOR_multicall(np->rx_mcl, mcl - np->rx_mcl); 1175 } 1176 } 1177 1178 __skb_queue_purge(&free_list); 1179 1180 spin_unlock_bh(&np->rx_lock); 1181 } 1182 1183 static void xennet_uninit(struct net_device *dev) 1184 { 1185 struct netfront_info *np = netdev_priv(dev); 1186 xennet_release_tx_bufs(np); 1187 xennet_release_rx_bufs(np); 1188 gnttab_free_grant_references(np->gref_tx_head); 1189 gnttab_free_grant_references(np->gref_rx_head); 1190 } 1191 1192 static u32 xennet_fix_features(struct net_device *dev, u32 features) 1193 { 1194 struct netfront_info *np = netdev_priv(dev); 1195 int val; 1196 1197 if (features & NETIF_F_SG) { 1198 if (xenbus_scanf(XBT_NIL, np->xbdev->otherend, "feature-sg", 1199 "%d", &val) < 0) 1200 val = 0; 1201 1202 if (!val) 1203 features &= ~NETIF_F_SG; 1204 } 1205 1206 if (features & NETIF_F_TSO) { 1207 if (xenbus_scanf(XBT_NIL, np->xbdev->otherend, 1208 "feature-gso-tcpv4", "%d", &val) < 0) 1209 val = 0; 1210 1211 if (!val) 1212 features &= ~NETIF_F_TSO; 1213 } 1214 1215 return features; 1216 } 1217 1218 static int xennet_set_features(struct net_device *dev, u32 features) 1219 { 1220 if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN) { 1221 netdev_info(dev, "Reducing MTU because no SG offload"); 1222 dev->mtu = ETH_DATA_LEN; 1223 } 1224 1225 return 0; 1226 } 1227 1228 static const struct net_device_ops xennet_netdev_ops = { 1229 .ndo_open = xennet_open, 1230 .ndo_uninit = xennet_uninit, 1231 .ndo_stop = xennet_close, 1232 .ndo_start_xmit = xennet_start_xmit, 1233 .ndo_change_mtu = xennet_change_mtu, 1234 .ndo_get_stats64 = xennet_get_stats64, 1235 .ndo_set_mac_address = eth_mac_addr, 1236 .ndo_validate_addr = eth_validate_addr, 1237 .ndo_fix_features = xennet_fix_features, 1238 .ndo_set_features = xennet_set_features, 1239 }; 1240 1241 static struct net_device * __devinit xennet_create_dev(struct xenbus_device *dev) 1242 { 1243 int i, err; 1244 struct net_device *netdev; 1245 struct netfront_info *np; 1246 1247 netdev = alloc_etherdev(sizeof(struct netfront_info)); 1248 if (!netdev) { 1249 printk(KERN_WARNING "%s> alloc_etherdev failed.\n", 1250 __func__); 1251 return ERR_PTR(-ENOMEM); 1252 } 1253 1254 np = netdev_priv(netdev); 1255 np->xbdev = dev; 1256 1257 spin_lock_init(&np->tx_lock); 1258 spin_lock_init(&np->rx_lock); 1259 1260 skb_queue_head_init(&np->rx_batch); 1261 np->rx_target = RX_DFL_MIN_TARGET; 1262 np->rx_min_target = RX_DFL_MIN_TARGET; 1263 np->rx_max_target = RX_MAX_TARGET; 1264 1265 init_timer(&np->rx_refill_timer); 1266 np->rx_refill_timer.data = (unsigned long)netdev; 1267 np->rx_refill_timer.function = rx_refill_timeout; 1268 1269 err = -ENOMEM; 1270 np->stats = alloc_percpu(struct netfront_stats); 1271 if (np->stats == NULL) 1272 goto exit; 1273 1274 /* Initialise tx_skbs as a free chain containing every entry. */ 1275 np->tx_skb_freelist = 0; 1276 for (i = 0; i < NET_TX_RING_SIZE; i++) { 1277 skb_entry_set_link(&np->tx_skbs[i], i+1); 1278 np->grant_tx_ref[i] = GRANT_INVALID_REF; 1279 } 1280 1281 /* Clear out rx_skbs */ 1282 for (i = 0; i < NET_RX_RING_SIZE; i++) { 1283 np->rx_skbs[i] = NULL; 1284 np->grant_rx_ref[i] = GRANT_INVALID_REF; 1285 } 1286 1287 /* A grant for every tx ring slot */ 1288 if (gnttab_alloc_grant_references(TX_MAX_TARGET, 1289 &np->gref_tx_head) < 0) { 1290 printk(KERN_ALERT "#### netfront can't alloc tx grant refs\n"); 1291 err = -ENOMEM; 1292 goto exit_free_stats; 1293 } 1294 /* A grant for every rx ring slot */ 1295 if (gnttab_alloc_grant_references(RX_MAX_TARGET, 1296 &np->gref_rx_head) < 0) { 1297 printk(KERN_ALERT "#### netfront can't alloc rx grant refs\n"); 1298 err = -ENOMEM; 1299 goto exit_free_tx; 1300 } 1301 1302 netdev->netdev_ops = &xennet_netdev_ops; 1303 1304 netif_napi_add(netdev, &np->napi, xennet_poll, 64); 1305 netdev->features = NETIF_F_IP_CSUM | NETIF_F_RXCSUM | 1306 NETIF_F_GSO_ROBUST; 1307 netdev->hw_features = NETIF_F_IP_CSUM | NETIF_F_SG | NETIF_F_TSO; 1308 1309 /* 1310 * Assume that all hw features are available for now. This set 1311 * will be adjusted by the call to netdev_update_features() in 1312 * xennet_connect() which is the earliest point where we can 1313 * negotiate with the backend regarding supported features. 1314 */ 1315 netdev->features |= netdev->hw_features; 1316 1317 SET_ETHTOOL_OPS(netdev, &xennet_ethtool_ops); 1318 SET_NETDEV_DEV(netdev, &dev->dev); 1319 1320 np->netdev = netdev; 1321 1322 netif_carrier_off(netdev); 1323 1324 return netdev; 1325 1326 exit_free_tx: 1327 gnttab_free_grant_references(np->gref_tx_head); 1328 exit_free_stats: 1329 free_percpu(np->stats); 1330 exit: 1331 free_netdev(netdev); 1332 return ERR_PTR(err); 1333 } 1334 1335 /** 1336 * Entry point to this code when a new device is created. Allocate the basic 1337 * structures and the ring buffers for communication with the backend, and 1338 * inform the backend of the appropriate details for those. 1339 */ 1340 static int __devinit netfront_probe(struct xenbus_device *dev, 1341 const struct xenbus_device_id *id) 1342 { 1343 int err; 1344 struct net_device *netdev; 1345 struct netfront_info *info; 1346 1347 netdev = xennet_create_dev(dev); 1348 if (IS_ERR(netdev)) { 1349 err = PTR_ERR(netdev); 1350 xenbus_dev_fatal(dev, err, "creating netdev"); 1351 return err; 1352 } 1353 1354 info = netdev_priv(netdev); 1355 dev_set_drvdata(&dev->dev, info); 1356 1357 err = register_netdev(info->netdev); 1358 if (err) { 1359 printk(KERN_WARNING "%s: register_netdev err=%d\n", 1360 __func__, err); 1361 goto fail; 1362 } 1363 1364 err = xennet_sysfs_addif(info->netdev); 1365 if (err) { 1366 unregister_netdev(info->netdev); 1367 printk(KERN_WARNING "%s: add sysfs failed err=%d\n", 1368 __func__, err); 1369 goto fail; 1370 } 1371 1372 return 0; 1373 1374 fail: 1375 free_netdev(netdev); 1376 dev_set_drvdata(&dev->dev, NULL); 1377 return err; 1378 } 1379 1380 static void xennet_end_access(int ref, void *page) 1381 { 1382 /* This frees the page as a side-effect */ 1383 if (ref != GRANT_INVALID_REF) 1384 gnttab_end_foreign_access(ref, 0, (unsigned long)page); 1385 } 1386 1387 static void xennet_disconnect_backend(struct netfront_info *info) 1388 { 1389 /* Stop old i/f to prevent errors whilst we rebuild the state. */ 1390 spin_lock_bh(&info->rx_lock); 1391 spin_lock_irq(&info->tx_lock); 1392 netif_carrier_off(info->netdev); 1393 spin_unlock_irq(&info->tx_lock); 1394 spin_unlock_bh(&info->rx_lock); 1395 1396 if (info->netdev->irq) 1397 unbind_from_irqhandler(info->netdev->irq, info->netdev); 1398 info->evtchn = info->netdev->irq = 0; 1399 1400 /* End access and free the pages */ 1401 xennet_end_access(info->tx_ring_ref, info->tx.sring); 1402 xennet_end_access(info->rx_ring_ref, info->rx.sring); 1403 1404 info->tx_ring_ref = GRANT_INVALID_REF; 1405 info->rx_ring_ref = GRANT_INVALID_REF; 1406 info->tx.sring = NULL; 1407 info->rx.sring = NULL; 1408 } 1409 1410 /** 1411 * We are reconnecting to the backend, due to a suspend/resume, or a backend 1412 * driver restart. We tear down our netif structure and recreate it, but 1413 * leave the device-layer structures intact so that this is transparent to the 1414 * rest of the kernel. 1415 */ 1416 static int netfront_resume(struct xenbus_device *dev) 1417 { 1418 struct netfront_info *info = dev_get_drvdata(&dev->dev); 1419 1420 dev_dbg(&dev->dev, "%s\n", dev->nodename); 1421 1422 xennet_disconnect_backend(info); 1423 return 0; 1424 } 1425 1426 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[]) 1427 { 1428 char *s, *e, *macstr; 1429 int i; 1430 1431 macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL); 1432 if (IS_ERR(macstr)) 1433 return PTR_ERR(macstr); 1434 1435 for (i = 0; i < ETH_ALEN; i++) { 1436 mac[i] = simple_strtoul(s, &e, 16); 1437 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) { 1438 kfree(macstr); 1439 return -ENOENT; 1440 } 1441 s = e+1; 1442 } 1443 1444 kfree(macstr); 1445 return 0; 1446 } 1447 1448 static irqreturn_t xennet_interrupt(int irq, void *dev_id) 1449 { 1450 struct net_device *dev = dev_id; 1451 struct netfront_info *np = netdev_priv(dev); 1452 unsigned long flags; 1453 1454 spin_lock_irqsave(&np->tx_lock, flags); 1455 1456 if (likely(netif_carrier_ok(dev))) { 1457 xennet_tx_buf_gc(dev); 1458 /* Under tx_lock: protects access to rx shared-ring indexes. */ 1459 if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx)) 1460 napi_schedule(&np->napi); 1461 } 1462 1463 spin_unlock_irqrestore(&np->tx_lock, flags); 1464 1465 return IRQ_HANDLED; 1466 } 1467 1468 static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info) 1469 { 1470 struct xen_netif_tx_sring *txs; 1471 struct xen_netif_rx_sring *rxs; 1472 int err; 1473 struct net_device *netdev = info->netdev; 1474 1475 info->tx_ring_ref = GRANT_INVALID_REF; 1476 info->rx_ring_ref = GRANT_INVALID_REF; 1477 info->rx.sring = NULL; 1478 info->tx.sring = NULL; 1479 netdev->irq = 0; 1480 1481 err = xen_net_read_mac(dev, netdev->dev_addr); 1482 if (err) { 1483 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename); 1484 goto fail; 1485 } 1486 1487 txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH); 1488 if (!txs) { 1489 err = -ENOMEM; 1490 xenbus_dev_fatal(dev, err, "allocating tx ring page"); 1491 goto fail; 1492 } 1493 SHARED_RING_INIT(txs); 1494 FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE); 1495 1496 err = xenbus_grant_ring(dev, virt_to_mfn(txs)); 1497 if (err < 0) { 1498 free_page((unsigned long)txs); 1499 goto fail; 1500 } 1501 1502 info->tx_ring_ref = err; 1503 rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH); 1504 if (!rxs) { 1505 err = -ENOMEM; 1506 xenbus_dev_fatal(dev, err, "allocating rx ring page"); 1507 goto fail; 1508 } 1509 SHARED_RING_INIT(rxs); 1510 FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE); 1511 1512 err = xenbus_grant_ring(dev, virt_to_mfn(rxs)); 1513 if (err < 0) { 1514 free_page((unsigned long)rxs); 1515 goto fail; 1516 } 1517 info->rx_ring_ref = err; 1518 1519 err = xenbus_alloc_evtchn(dev, &info->evtchn); 1520 if (err) 1521 goto fail; 1522 1523 err = bind_evtchn_to_irqhandler(info->evtchn, xennet_interrupt, 1524 0, netdev->name, netdev); 1525 if (err < 0) 1526 goto fail; 1527 netdev->irq = err; 1528 return 0; 1529 1530 fail: 1531 return err; 1532 } 1533 1534 /* Common code used when first setting up, and when resuming. */ 1535 static int talk_to_netback(struct xenbus_device *dev, 1536 struct netfront_info *info) 1537 { 1538 const char *message; 1539 struct xenbus_transaction xbt; 1540 int err; 1541 1542 /* Create shared ring, alloc event channel. */ 1543 err = setup_netfront(dev, info); 1544 if (err) 1545 goto out; 1546 1547 again: 1548 err = xenbus_transaction_start(&xbt); 1549 if (err) { 1550 xenbus_dev_fatal(dev, err, "starting transaction"); 1551 goto destroy_ring; 1552 } 1553 1554 err = xenbus_printf(xbt, dev->nodename, "tx-ring-ref", "%u", 1555 info->tx_ring_ref); 1556 if (err) { 1557 message = "writing tx ring-ref"; 1558 goto abort_transaction; 1559 } 1560 err = xenbus_printf(xbt, dev->nodename, "rx-ring-ref", "%u", 1561 info->rx_ring_ref); 1562 if (err) { 1563 message = "writing rx ring-ref"; 1564 goto abort_transaction; 1565 } 1566 err = xenbus_printf(xbt, dev->nodename, 1567 "event-channel", "%u", info->evtchn); 1568 if (err) { 1569 message = "writing event-channel"; 1570 goto abort_transaction; 1571 } 1572 1573 err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u", 1574 1); 1575 if (err) { 1576 message = "writing request-rx-copy"; 1577 goto abort_transaction; 1578 } 1579 1580 err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1); 1581 if (err) { 1582 message = "writing feature-rx-notify"; 1583 goto abort_transaction; 1584 } 1585 1586 err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1); 1587 if (err) { 1588 message = "writing feature-sg"; 1589 goto abort_transaction; 1590 } 1591 1592 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1); 1593 if (err) { 1594 message = "writing feature-gso-tcpv4"; 1595 goto abort_transaction; 1596 } 1597 1598 err = xenbus_transaction_end(xbt, 0); 1599 if (err) { 1600 if (err == -EAGAIN) 1601 goto again; 1602 xenbus_dev_fatal(dev, err, "completing transaction"); 1603 goto destroy_ring; 1604 } 1605 1606 return 0; 1607 1608 abort_transaction: 1609 xenbus_transaction_end(xbt, 1); 1610 xenbus_dev_fatal(dev, err, "%s", message); 1611 destroy_ring: 1612 xennet_disconnect_backend(info); 1613 out: 1614 return err; 1615 } 1616 1617 static int xennet_connect(struct net_device *dev) 1618 { 1619 struct netfront_info *np = netdev_priv(dev); 1620 int i, requeue_idx, err; 1621 struct sk_buff *skb; 1622 grant_ref_t ref; 1623 struct xen_netif_rx_request *req; 1624 unsigned int feature_rx_copy; 1625 1626 err = xenbus_scanf(XBT_NIL, np->xbdev->otherend, 1627 "feature-rx-copy", "%u", &feature_rx_copy); 1628 if (err != 1) 1629 feature_rx_copy = 0; 1630 1631 if (!feature_rx_copy) { 1632 dev_info(&dev->dev, 1633 "backend does not support copying receive path\n"); 1634 return -ENODEV; 1635 } 1636 1637 err = talk_to_netback(np->xbdev, np); 1638 if (err) 1639 return err; 1640 1641 rtnl_lock(); 1642 netdev_update_features(dev); 1643 rtnl_unlock(); 1644 1645 spin_lock_bh(&np->rx_lock); 1646 spin_lock_irq(&np->tx_lock); 1647 1648 /* Step 1: Discard all pending TX packet fragments. */ 1649 xennet_release_tx_bufs(np); 1650 1651 /* Step 2: Rebuild the RX buffer freelist and the RX ring itself. */ 1652 for (requeue_idx = 0, i = 0; i < NET_RX_RING_SIZE; i++) { 1653 if (!np->rx_skbs[i]) 1654 continue; 1655 1656 skb = np->rx_skbs[requeue_idx] = xennet_get_rx_skb(np, i); 1657 ref = np->grant_rx_ref[requeue_idx] = xennet_get_rx_ref(np, i); 1658 req = RING_GET_REQUEST(&np->rx, requeue_idx); 1659 1660 gnttab_grant_foreign_access_ref( 1661 ref, np->xbdev->otherend_id, 1662 pfn_to_mfn(page_to_pfn(skb_shinfo(skb)-> 1663 frags->page)), 1664 0); 1665 req->gref = ref; 1666 req->id = requeue_idx; 1667 1668 requeue_idx++; 1669 } 1670 1671 np->rx.req_prod_pvt = requeue_idx; 1672 1673 /* 1674 * Step 3: All public and private state should now be sane. Get 1675 * ready to start sending and receiving packets and give the driver 1676 * domain a kick because we've probably just requeued some 1677 * packets. 1678 */ 1679 netif_carrier_on(np->netdev); 1680 notify_remote_via_irq(np->netdev->irq); 1681 xennet_tx_buf_gc(dev); 1682 xennet_alloc_rx_buffers(dev); 1683 1684 spin_unlock_irq(&np->tx_lock); 1685 spin_unlock_bh(&np->rx_lock); 1686 1687 return 0; 1688 } 1689 1690 /** 1691 * Callback received when the backend's state changes. 1692 */ 1693 static void netback_changed(struct xenbus_device *dev, 1694 enum xenbus_state backend_state) 1695 { 1696 struct netfront_info *np = dev_get_drvdata(&dev->dev); 1697 struct net_device *netdev = np->netdev; 1698 1699 dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state)); 1700 1701 switch (backend_state) { 1702 case XenbusStateInitialising: 1703 case XenbusStateInitialised: 1704 case XenbusStateReconfiguring: 1705 case XenbusStateReconfigured: 1706 case XenbusStateConnected: 1707 case XenbusStateUnknown: 1708 case XenbusStateClosed: 1709 break; 1710 1711 case XenbusStateInitWait: 1712 if (dev->state != XenbusStateInitialising) 1713 break; 1714 if (xennet_connect(netdev) != 0) 1715 break; 1716 xenbus_switch_state(dev, XenbusStateConnected); 1717 netif_notify_peers(netdev); 1718 break; 1719 1720 case XenbusStateClosing: 1721 xenbus_frontend_closed(dev); 1722 break; 1723 } 1724 } 1725 1726 static const struct xennet_stat { 1727 char name[ETH_GSTRING_LEN]; 1728 u16 offset; 1729 } xennet_stats[] = { 1730 { 1731 "rx_gso_checksum_fixup", 1732 offsetof(struct netfront_info, rx_gso_checksum_fixup) 1733 }, 1734 }; 1735 1736 static int xennet_get_sset_count(struct net_device *dev, int string_set) 1737 { 1738 switch (string_set) { 1739 case ETH_SS_STATS: 1740 return ARRAY_SIZE(xennet_stats); 1741 default: 1742 return -EINVAL; 1743 } 1744 } 1745 1746 static void xennet_get_ethtool_stats(struct net_device *dev, 1747 struct ethtool_stats *stats, u64 * data) 1748 { 1749 void *np = netdev_priv(dev); 1750 int i; 1751 1752 for (i = 0; i < ARRAY_SIZE(xennet_stats); i++) 1753 data[i] = *(unsigned long *)(np + xennet_stats[i].offset); 1754 } 1755 1756 static void xennet_get_strings(struct net_device *dev, u32 stringset, u8 * data) 1757 { 1758 int i; 1759 1760 switch (stringset) { 1761 case ETH_SS_STATS: 1762 for (i = 0; i < ARRAY_SIZE(xennet_stats); i++) 1763 memcpy(data + i * ETH_GSTRING_LEN, 1764 xennet_stats[i].name, ETH_GSTRING_LEN); 1765 break; 1766 } 1767 } 1768 1769 static const struct ethtool_ops xennet_ethtool_ops = 1770 { 1771 .get_link = ethtool_op_get_link, 1772 1773 .get_sset_count = xennet_get_sset_count, 1774 .get_ethtool_stats = xennet_get_ethtool_stats, 1775 .get_strings = xennet_get_strings, 1776 }; 1777 1778 #ifdef CONFIG_SYSFS 1779 static ssize_t show_rxbuf_min(struct device *dev, 1780 struct device_attribute *attr, char *buf) 1781 { 1782 struct net_device *netdev = to_net_dev(dev); 1783 struct netfront_info *info = netdev_priv(netdev); 1784 1785 return sprintf(buf, "%u\n", info->rx_min_target); 1786 } 1787 1788 static ssize_t store_rxbuf_min(struct device *dev, 1789 struct device_attribute *attr, 1790 const char *buf, size_t len) 1791 { 1792 struct net_device *netdev = to_net_dev(dev); 1793 struct netfront_info *np = netdev_priv(netdev); 1794 char *endp; 1795 unsigned long target; 1796 1797 if (!capable(CAP_NET_ADMIN)) 1798 return -EPERM; 1799 1800 target = simple_strtoul(buf, &endp, 0); 1801 if (endp == buf) 1802 return -EBADMSG; 1803 1804 if (target < RX_MIN_TARGET) 1805 target = RX_MIN_TARGET; 1806 if (target > RX_MAX_TARGET) 1807 target = RX_MAX_TARGET; 1808 1809 spin_lock_bh(&np->rx_lock); 1810 if (target > np->rx_max_target) 1811 np->rx_max_target = target; 1812 np->rx_min_target = target; 1813 if (target > np->rx_target) 1814 np->rx_target = target; 1815 1816 xennet_alloc_rx_buffers(netdev); 1817 1818 spin_unlock_bh(&np->rx_lock); 1819 return len; 1820 } 1821 1822 static ssize_t show_rxbuf_max(struct device *dev, 1823 struct device_attribute *attr, char *buf) 1824 { 1825 struct net_device *netdev = to_net_dev(dev); 1826 struct netfront_info *info = netdev_priv(netdev); 1827 1828 return sprintf(buf, "%u\n", info->rx_max_target); 1829 } 1830 1831 static ssize_t store_rxbuf_max(struct device *dev, 1832 struct device_attribute *attr, 1833 const char *buf, size_t len) 1834 { 1835 struct net_device *netdev = to_net_dev(dev); 1836 struct netfront_info *np = netdev_priv(netdev); 1837 char *endp; 1838 unsigned long target; 1839 1840 if (!capable(CAP_NET_ADMIN)) 1841 return -EPERM; 1842 1843 target = simple_strtoul(buf, &endp, 0); 1844 if (endp == buf) 1845 return -EBADMSG; 1846 1847 if (target < RX_MIN_TARGET) 1848 target = RX_MIN_TARGET; 1849 if (target > RX_MAX_TARGET) 1850 target = RX_MAX_TARGET; 1851 1852 spin_lock_bh(&np->rx_lock); 1853 if (target < np->rx_min_target) 1854 np->rx_min_target = target; 1855 np->rx_max_target = target; 1856 if (target < np->rx_target) 1857 np->rx_target = target; 1858 1859 xennet_alloc_rx_buffers(netdev); 1860 1861 spin_unlock_bh(&np->rx_lock); 1862 return len; 1863 } 1864 1865 static ssize_t show_rxbuf_cur(struct device *dev, 1866 struct device_attribute *attr, char *buf) 1867 { 1868 struct net_device *netdev = to_net_dev(dev); 1869 struct netfront_info *info = netdev_priv(netdev); 1870 1871 return sprintf(buf, "%u\n", info->rx_target); 1872 } 1873 1874 static struct device_attribute xennet_attrs[] = { 1875 __ATTR(rxbuf_min, S_IRUGO|S_IWUSR, show_rxbuf_min, store_rxbuf_min), 1876 __ATTR(rxbuf_max, S_IRUGO|S_IWUSR, show_rxbuf_max, store_rxbuf_max), 1877 __ATTR(rxbuf_cur, S_IRUGO, show_rxbuf_cur, NULL), 1878 }; 1879 1880 static int xennet_sysfs_addif(struct net_device *netdev) 1881 { 1882 int i; 1883 int err; 1884 1885 for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++) { 1886 err = device_create_file(&netdev->dev, 1887 &xennet_attrs[i]); 1888 if (err) 1889 goto fail; 1890 } 1891 return 0; 1892 1893 fail: 1894 while (--i >= 0) 1895 device_remove_file(&netdev->dev, &xennet_attrs[i]); 1896 return err; 1897 } 1898 1899 static void xennet_sysfs_delif(struct net_device *netdev) 1900 { 1901 int i; 1902 1903 for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++) 1904 device_remove_file(&netdev->dev, &xennet_attrs[i]); 1905 } 1906 1907 #endif /* CONFIG_SYSFS */ 1908 1909 static struct xenbus_device_id netfront_ids[] = { 1910 { "vif" }, 1911 { "" } 1912 }; 1913 1914 1915 static int __devexit xennet_remove(struct xenbus_device *dev) 1916 { 1917 struct netfront_info *info = dev_get_drvdata(&dev->dev); 1918 1919 dev_dbg(&dev->dev, "%s\n", dev->nodename); 1920 1921 unregister_netdev(info->netdev); 1922 1923 xennet_disconnect_backend(info); 1924 1925 del_timer_sync(&info->rx_refill_timer); 1926 1927 xennet_sysfs_delif(info->netdev); 1928 1929 free_percpu(info->stats); 1930 1931 free_netdev(info->netdev); 1932 1933 return 0; 1934 } 1935 1936 static struct xenbus_driver netfront_driver = { 1937 .name = "vif", 1938 .owner = THIS_MODULE, 1939 .ids = netfront_ids, 1940 .probe = netfront_probe, 1941 .remove = __devexit_p(xennet_remove), 1942 .resume = netfront_resume, 1943 .otherend_changed = netback_changed, 1944 }; 1945 1946 static int __init netif_init(void) 1947 { 1948 if (!xen_domain()) 1949 return -ENODEV; 1950 1951 if (xen_initial_domain()) 1952 return 0; 1953 1954 printk(KERN_INFO "Initialising Xen virtual ethernet driver.\n"); 1955 1956 return xenbus_register_frontend(&netfront_driver); 1957 } 1958 module_init(netif_init); 1959 1960 1961 static void __exit netif_exit(void) 1962 { 1963 if (xen_initial_domain()) 1964 return; 1965 1966 xenbus_unregister_driver(&netfront_driver); 1967 } 1968 module_exit(netif_exit); 1969 1970 MODULE_DESCRIPTION("Xen virtual network device frontend"); 1971 MODULE_LICENSE("GPL"); 1972 MODULE_ALIAS("xen:vif"); 1973 MODULE_ALIAS("xennet"); 1974