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 <asm/xen/page.h> 47 #include <xen/xen.h> 48 #include <xen/xenbus.h> 49 #include <xen/events.h> 50 #include <xen/page.h> 51 #include <xen/platform_pci.h> 52 #include <xen/grant_table.h> 53 54 #include <xen/interface/io/netif.h> 55 #include <xen/interface/memory.h> 56 #include <xen/interface/grant_table.h> 57 58 static const struct ethtool_ops xennet_ethtool_ops; 59 60 struct netfront_cb { 61 int pull_to; 62 }; 63 64 #define NETFRONT_SKB_CB(skb) ((struct netfront_cb *)((skb)->cb)) 65 66 #define RX_COPY_THRESHOLD 256 67 68 #define GRANT_INVALID_REF 0 69 70 #define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE) 71 #define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE) 72 #define TX_MAX_TARGET min_t(int, NET_TX_RING_SIZE, 256) 73 74 struct netfront_stats { 75 u64 rx_packets; 76 u64 tx_packets; 77 u64 rx_bytes; 78 u64 tx_bytes; 79 struct u64_stats_sync syncp; 80 }; 81 82 struct netfront_info { 83 struct list_head list; 84 struct net_device *netdev; 85 86 struct napi_struct napi; 87 88 unsigned int evtchn; 89 struct xenbus_device *xbdev; 90 91 spinlock_t tx_lock; 92 struct xen_netif_tx_front_ring tx; 93 int tx_ring_ref; 94 95 /* 96 * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries 97 * are linked from tx_skb_freelist through skb_entry.link. 98 * 99 * NB. Freelist index entries are always going to be less than 100 * PAGE_OFFSET, whereas pointers to skbs will always be equal or 101 * greater than PAGE_OFFSET: we use this property to distinguish 102 * them. 103 */ 104 union skb_entry { 105 struct sk_buff *skb; 106 unsigned long link; 107 } tx_skbs[NET_TX_RING_SIZE]; 108 grant_ref_t gref_tx_head; 109 grant_ref_t grant_tx_ref[NET_TX_RING_SIZE]; 110 unsigned tx_skb_freelist; 111 112 spinlock_t rx_lock ____cacheline_aligned_in_smp; 113 struct xen_netif_rx_front_ring rx; 114 int rx_ring_ref; 115 116 /* Receive-ring batched refills. */ 117 #define RX_MIN_TARGET 8 118 #define RX_DFL_MIN_TARGET 64 119 #define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256) 120 unsigned rx_min_target, rx_max_target, rx_target; 121 struct sk_buff_head rx_batch; 122 123 struct timer_list rx_refill_timer; 124 125 struct sk_buff *rx_skbs[NET_RX_RING_SIZE]; 126 grant_ref_t gref_rx_head; 127 grant_ref_t grant_rx_ref[NET_RX_RING_SIZE]; 128 129 unsigned long rx_pfn_array[NET_RX_RING_SIZE]; 130 struct multicall_entry rx_mcl[NET_RX_RING_SIZE+1]; 131 struct mmu_update rx_mmu[NET_RX_RING_SIZE]; 132 133 /* Statistics */ 134 struct netfront_stats __percpu *stats; 135 136 unsigned long rx_gso_checksum_fixup; 137 }; 138 139 struct netfront_rx_info { 140 struct xen_netif_rx_response rx; 141 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1]; 142 }; 143 144 static void skb_entry_set_link(union skb_entry *list, unsigned short id) 145 { 146 list->link = id; 147 } 148 149 static int skb_entry_is_link(const union skb_entry *list) 150 { 151 BUILD_BUG_ON(sizeof(list->skb) != sizeof(list->link)); 152 return (unsigned long)list->skb < PAGE_OFFSET; 153 } 154 155 /* 156 * Access macros for acquiring freeing slots in tx_skbs[]. 157 */ 158 159 static void add_id_to_freelist(unsigned *head, union skb_entry *list, 160 unsigned short id) 161 { 162 skb_entry_set_link(&list[id], *head); 163 *head = id; 164 } 165 166 static unsigned short get_id_from_freelist(unsigned *head, 167 union skb_entry *list) 168 { 169 unsigned int id = *head; 170 *head = list[id].link; 171 return id; 172 } 173 174 static int xennet_rxidx(RING_IDX idx) 175 { 176 return idx & (NET_RX_RING_SIZE - 1); 177 } 178 179 static struct sk_buff *xennet_get_rx_skb(struct netfront_info *np, 180 RING_IDX ri) 181 { 182 int i = xennet_rxidx(ri); 183 struct sk_buff *skb = np->rx_skbs[i]; 184 np->rx_skbs[i] = NULL; 185 return skb; 186 } 187 188 static grant_ref_t xennet_get_rx_ref(struct netfront_info *np, 189 RING_IDX ri) 190 { 191 int i = xennet_rxidx(ri); 192 grant_ref_t ref = np->grant_rx_ref[i]; 193 np->grant_rx_ref[i] = GRANT_INVALID_REF; 194 return ref; 195 } 196 197 #ifdef CONFIG_SYSFS 198 static int xennet_sysfs_addif(struct net_device *netdev); 199 static void xennet_sysfs_delif(struct net_device *netdev); 200 #else /* !CONFIG_SYSFS */ 201 #define xennet_sysfs_addif(dev) (0) 202 #define xennet_sysfs_delif(dev) do { } while (0) 203 #endif 204 205 static bool xennet_can_sg(struct net_device *dev) 206 { 207 return dev->features & NETIF_F_SG; 208 } 209 210 211 static void rx_refill_timeout(unsigned long data) 212 { 213 struct net_device *dev = (struct net_device *)data; 214 struct netfront_info *np = netdev_priv(dev); 215 napi_schedule(&np->napi); 216 } 217 218 static int netfront_tx_slot_available(struct netfront_info *np) 219 { 220 return (np->tx.req_prod_pvt - np->tx.rsp_cons) < 221 (TX_MAX_TARGET - MAX_SKB_FRAGS - 2); 222 } 223 224 static void xennet_maybe_wake_tx(struct net_device *dev) 225 { 226 struct netfront_info *np = netdev_priv(dev); 227 228 if (unlikely(netif_queue_stopped(dev)) && 229 netfront_tx_slot_available(np) && 230 likely(netif_running(dev))) 231 netif_wake_queue(dev); 232 } 233 234 static void xennet_alloc_rx_buffers(struct net_device *dev) 235 { 236 unsigned short id; 237 struct netfront_info *np = netdev_priv(dev); 238 struct sk_buff *skb; 239 struct page *page; 240 int i, batch_target, notify; 241 RING_IDX req_prod = np->rx.req_prod_pvt; 242 grant_ref_t ref; 243 unsigned long pfn; 244 void *vaddr; 245 struct xen_netif_rx_request *req; 246 247 if (unlikely(!netif_carrier_ok(dev))) 248 return; 249 250 /* 251 * Allocate skbuffs greedily, even though we batch updates to the 252 * receive ring. This creates a less bursty demand on the memory 253 * allocator, so should reduce the chance of failed allocation requests 254 * both for ourself and for other kernel subsystems. 255 */ 256 batch_target = np->rx_target - (req_prod - np->rx.rsp_cons); 257 for (i = skb_queue_len(&np->rx_batch); i < batch_target; i++) { 258 skb = __netdev_alloc_skb(dev, RX_COPY_THRESHOLD + NET_IP_ALIGN, 259 GFP_ATOMIC | __GFP_NOWARN); 260 if (unlikely(!skb)) 261 goto no_skb; 262 263 /* Align ip header to a 16 bytes boundary */ 264 skb_reserve(skb, NET_IP_ALIGN); 265 266 page = alloc_page(GFP_ATOMIC | __GFP_NOWARN); 267 if (!page) { 268 kfree_skb(skb); 269 no_skb: 270 /* Any skbuffs queued for refill? Force them out. */ 271 if (i != 0) 272 goto refill; 273 /* Could not allocate any skbuffs. Try again later. */ 274 mod_timer(&np->rx_refill_timer, 275 jiffies + (HZ/10)); 276 break; 277 } 278 279 __skb_fill_page_desc(skb, 0, page, 0, 0); 280 skb_shinfo(skb)->nr_frags = 1; 281 __skb_queue_tail(&np->rx_batch, skb); 282 } 283 284 /* Is the batch large enough to be worthwhile? */ 285 if (i < (np->rx_target/2)) { 286 if (req_prod > np->rx.sring->req_prod) 287 goto push; 288 return; 289 } 290 291 /* Adjust our fill target if we risked running out of buffers. */ 292 if (((req_prod - np->rx.sring->rsp_prod) < (np->rx_target / 4)) && 293 ((np->rx_target *= 2) > np->rx_max_target)) 294 np->rx_target = np->rx_max_target; 295 296 refill: 297 for (i = 0; ; i++) { 298 skb = __skb_dequeue(&np->rx_batch); 299 if (skb == NULL) 300 break; 301 302 skb->dev = dev; 303 304 id = xennet_rxidx(req_prod + i); 305 306 BUG_ON(np->rx_skbs[id]); 307 np->rx_skbs[id] = skb; 308 309 ref = gnttab_claim_grant_reference(&np->gref_rx_head); 310 BUG_ON((signed short)ref < 0); 311 np->grant_rx_ref[id] = ref; 312 313 pfn = page_to_pfn(skb_frag_page(&skb_shinfo(skb)->frags[0])); 314 vaddr = page_address(skb_frag_page(&skb_shinfo(skb)->frags[0])); 315 316 req = RING_GET_REQUEST(&np->rx, req_prod + i); 317 gnttab_grant_foreign_access_ref(ref, 318 np->xbdev->otherend_id, 319 pfn_to_mfn(pfn), 320 0); 321 322 req->id = id; 323 req->gref = ref; 324 } 325 326 wmb(); /* barrier so backend seens requests */ 327 328 /* Above is a suitable barrier to ensure backend will see requests. */ 329 np->rx.req_prod_pvt = req_prod + i; 330 push: 331 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->rx, notify); 332 if (notify) 333 notify_remote_via_irq(np->netdev->irq); 334 } 335 336 static int xennet_open(struct net_device *dev) 337 { 338 struct netfront_info *np = netdev_priv(dev); 339 340 napi_enable(&np->napi); 341 342 spin_lock_bh(&np->rx_lock); 343 if (netif_carrier_ok(dev)) { 344 xennet_alloc_rx_buffers(dev); 345 np->rx.sring->rsp_event = np->rx.rsp_cons + 1; 346 if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx)) 347 napi_schedule(&np->napi); 348 } 349 spin_unlock_bh(&np->rx_lock); 350 351 netif_start_queue(dev); 352 353 return 0; 354 } 355 356 static void xennet_tx_buf_gc(struct net_device *dev) 357 { 358 RING_IDX cons, prod; 359 unsigned short id; 360 struct netfront_info *np = netdev_priv(dev); 361 struct sk_buff *skb; 362 363 BUG_ON(!netif_carrier_ok(dev)); 364 365 do { 366 prod = np->tx.sring->rsp_prod; 367 rmb(); /* Ensure we see responses up to 'rp'. */ 368 369 for (cons = np->tx.rsp_cons; cons != prod; cons++) { 370 struct xen_netif_tx_response *txrsp; 371 372 txrsp = RING_GET_RESPONSE(&np->tx, cons); 373 if (txrsp->status == XEN_NETIF_RSP_NULL) 374 continue; 375 376 id = txrsp->id; 377 skb = np->tx_skbs[id].skb; 378 if (unlikely(gnttab_query_foreign_access( 379 np->grant_tx_ref[id]) != 0)) { 380 printk(KERN_ALERT "xennet_tx_buf_gc: warning " 381 "-- grant still in use by backend " 382 "domain.\n"); 383 BUG(); 384 } 385 gnttab_end_foreign_access_ref( 386 np->grant_tx_ref[id], GNTMAP_readonly); 387 gnttab_release_grant_reference( 388 &np->gref_tx_head, np->grant_tx_ref[id]); 389 np->grant_tx_ref[id] = GRANT_INVALID_REF; 390 add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, id); 391 dev_kfree_skb_irq(skb); 392 } 393 394 np->tx.rsp_cons = prod; 395 396 /* 397 * Set a new event, then check for race with update of tx_cons. 398 * Note that it is essential to schedule a callback, no matter 399 * how few buffers are pending. Even if there is space in the 400 * transmit ring, higher layers may be blocked because too much 401 * data is outstanding: in such cases notification from Xen is 402 * likely to be the only kick that we'll get. 403 */ 404 np->tx.sring->rsp_event = 405 prod + ((np->tx.sring->req_prod - prod) >> 1) + 1; 406 mb(); /* update shared area */ 407 } while ((cons == prod) && (prod != np->tx.sring->rsp_prod)); 408 409 xennet_maybe_wake_tx(dev); 410 } 411 412 static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev, 413 struct xen_netif_tx_request *tx) 414 { 415 struct netfront_info *np = netdev_priv(dev); 416 char *data = skb->data; 417 unsigned long mfn; 418 RING_IDX prod = np->tx.req_prod_pvt; 419 int frags = skb_shinfo(skb)->nr_frags; 420 unsigned int offset = offset_in_page(data); 421 unsigned int len = skb_headlen(skb); 422 unsigned int id; 423 grant_ref_t ref; 424 int i; 425 426 /* While the header overlaps a page boundary (including being 427 larger than a page), split it it into page-sized chunks. */ 428 while (len > PAGE_SIZE - offset) { 429 tx->size = PAGE_SIZE - offset; 430 tx->flags |= XEN_NETTXF_more_data; 431 len -= tx->size; 432 data += tx->size; 433 offset = 0; 434 435 id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs); 436 np->tx_skbs[id].skb = skb_get(skb); 437 tx = RING_GET_REQUEST(&np->tx, prod++); 438 tx->id = id; 439 ref = gnttab_claim_grant_reference(&np->gref_tx_head); 440 BUG_ON((signed short)ref < 0); 441 442 mfn = virt_to_mfn(data); 443 gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id, 444 mfn, GNTMAP_readonly); 445 446 tx->gref = np->grant_tx_ref[id] = ref; 447 tx->offset = offset; 448 tx->size = len; 449 tx->flags = 0; 450 } 451 452 /* Grant backend access to each skb fragment page. */ 453 for (i = 0; i < frags; i++) { 454 skb_frag_t *frag = skb_shinfo(skb)->frags + i; 455 struct page *page = skb_frag_page(frag); 456 457 len = skb_frag_size(frag); 458 offset = frag->page_offset; 459 460 /* Data must not cross a page boundary. */ 461 BUG_ON(len + offset > PAGE_SIZE<<compound_order(page)); 462 463 /* Skip unused frames from start of page */ 464 page += offset >> PAGE_SHIFT; 465 offset &= ~PAGE_MASK; 466 467 while (len > 0) { 468 unsigned long bytes; 469 470 BUG_ON(offset >= PAGE_SIZE); 471 472 bytes = PAGE_SIZE - offset; 473 if (bytes > len) 474 bytes = len; 475 476 tx->flags |= XEN_NETTXF_more_data; 477 478 id = get_id_from_freelist(&np->tx_skb_freelist, 479 np->tx_skbs); 480 np->tx_skbs[id].skb = skb_get(skb); 481 tx = RING_GET_REQUEST(&np->tx, prod++); 482 tx->id = id; 483 ref = gnttab_claim_grant_reference(&np->gref_tx_head); 484 BUG_ON((signed short)ref < 0); 485 486 mfn = pfn_to_mfn(page_to_pfn(page)); 487 gnttab_grant_foreign_access_ref(ref, 488 np->xbdev->otherend_id, 489 mfn, GNTMAP_readonly); 490 491 tx->gref = np->grant_tx_ref[id] = ref; 492 tx->offset = offset; 493 tx->size = bytes; 494 tx->flags = 0; 495 496 offset += bytes; 497 len -= bytes; 498 499 /* Next frame */ 500 if (offset == PAGE_SIZE && len) { 501 BUG_ON(!PageCompound(page)); 502 page++; 503 offset = 0; 504 } 505 } 506 } 507 508 np->tx.req_prod_pvt = prod; 509 } 510 511 /* 512 * Count how many ring slots are required to send the frags of this 513 * skb. Each frag might be a compound page. 514 */ 515 static int xennet_count_skb_frag_slots(struct sk_buff *skb) 516 { 517 int i, frags = skb_shinfo(skb)->nr_frags; 518 int pages = 0; 519 520 for (i = 0; i < frags; i++) { 521 skb_frag_t *frag = skb_shinfo(skb)->frags + i; 522 unsigned long size = skb_frag_size(frag); 523 unsigned long offset = frag->page_offset; 524 525 /* Skip unused frames from start of page */ 526 offset &= ~PAGE_MASK; 527 528 pages += PFN_UP(offset + size); 529 } 530 531 return pages; 532 } 533 534 static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev) 535 { 536 unsigned short id; 537 struct netfront_info *np = netdev_priv(dev); 538 struct netfront_stats *stats = this_cpu_ptr(np->stats); 539 struct xen_netif_tx_request *tx; 540 struct xen_netif_extra_info *extra; 541 char *data = skb->data; 542 RING_IDX i; 543 grant_ref_t ref; 544 unsigned long mfn; 545 int notify; 546 int slots; 547 unsigned int offset = offset_in_page(data); 548 unsigned int len = skb_headlen(skb); 549 unsigned long flags; 550 551 slots = DIV_ROUND_UP(offset + len, PAGE_SIZE) + 552 xennet_count_skb_frag_slots(skb); 553 if (unlikely(slots > MAX_SKB_FRAGS + 1)) { 554 net_alert_ratelimited( 555 "xennet: skb rides the rocket: %d slots\n", slots); 556 goto drop; 557 } 558 559 spin_lock_irqsave(&np->tx_lock, flags); 560 561 if (unlikely(!netif_carrier_ok(dev) || 562 (slots > 1 && !xennet_can_sg(dev)) || 563 netif_needs_gso(skb, netif_skb_features(skb)))) { 564 spin_unlock_irqrestore(&np->tx_lock, flags); 565 goto drop; 566 } 567 568 i = np->tx.req_prod_pvt; 569 570 id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs); 571 np->tx_skbs[id].skb = skb; 572 573 tx = RING_GET_REQUEST(&np->tx, i); 574 575 tx->id = id; 576 ref = gnttab_claim_grant_reference(&np->gref_tx_head); 577 BUG_ON((signed short)ref < 0); 578 mfn = virt_to_mfn(data); 579 gnttab_grant_foreign_access_ref( 580 ref, np->xbdev->otherend_id, mfn, GNTMAP_readonly); 581 tx->gref = np->grant_tx_ref[id] = ref; 582 tx->offset = offset; 583 tx->size = len; 584 extra = NULL; 585 586 tx->flags = 0; 587 if (skb->ip_summed == CHECKSUM_PARTIAL) 588 /* local packet? */ 589 tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated; 590 else if (skb->ip_summed == CHECKSUM_UNNECESSARY) 591 /* remote but checksummed. */ 592 tx->flags |= XEN_NETTXF_data_validated; 593 594 if (skb_shinfo(skb)->gso_size) { 595 struct xen_netif_extra_info *gso; 596 597 gso = (struct xen_netif_extra_info *) 598 RING_GET_REQUEST(&np->tx, ++i); 599 600 if (extra) 601 extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE; 602 else 603 tx->flags |= XEN_NETTXF_extra_info; 604 605 gso->u.gso.size = skb_shinfo(skb)->gso_size; 606 gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4; 607 gso->u.gso.pad = 0; 608 gso->u.gso.features = 0; 609 610 gso->type = XEN_NETIF_EXTRA_TYPE_GSO; 611 gso->flags = 0; 612 extra = gso; 613 } 614 615 np->tx.req_prod_pvt = i + 1; 616 617 xennet_make_frags(skb, dev, tx); 618 tx->size = skb->len; 619 620 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->tx, notify); 621 if (notify) 622 notify_remote_via_irq(np->netdev->irq); 623 624 u64_stats_update_begin(&stats->syncp); 625 stats->tx_bytes += skb->len; 626 stats->tx_packets++; 627 u64_stats_update_end(&stats->syncp); 628 629 /* Note: It is not safe to access skb after xennet_tx_buf_gc()! */ 630 xennet_tx_buf_gc(dev); 631 632 if (!netfront_tx_slot_available(np)) 633 netif_stop_queue(dev); 634 635 spin_unlock_irqrestore(&np->tx_lock, flags); 636 637 return NETDEV_TX_OK; 638 639 drop: 640 dev->stats.tx_dropped++; 641 dev_kfree_skb(skb); 642 return NETDEV_TX_OK; 643 } 644 645 static int xennet_close(struct net_device *dev) 646 { 647 struct netfront_info *np = netdev_priv(dev); 648 netif_stop_queue(np->netdev); 649 napi_disable(&np->napi); 650 return 0; 651 } 652 653 static void xennet_move_rx_slot(struct netfront_info *np, struct sk_buff *skb, 654 grant_ref_t ref) 655 { 656 int new = xennet_rxidx(np->rx.req_prod_pvt); 657 658 BUG_ON(np->rx_skbs[new]); 659 np->rx_skbs[new] = skb; 660 np->grant_rx_ref[new] = ref; 661 RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->id = new; 662 RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->gref = ref; 663 np->rx.req_prod_pvt++; 664 } 665 666 static int xennet_get_extras(struct netfront_info *np, 667 struct xen_netif_extra_info *extras, 668 RING_IDX rp) 669 670 { 671 struct xen_netif_extra_info *extra; 672 struct device *dev = &np->netdev->dev; 673 RING_IDX cons = np->rx.rsp_cons; 674 int err = 0; 675 676 do { 677 struct sk_buff *skb; 678 grant_ref_t ref; 679 680 if (unlikely(cons + 1 == rp)) { 681 if (net_ratelimit()) 682 dev_warn(dev, "Missing extra info\n"); 683 err = -EBADR; 684 break; 685 } 686 687 extra = (struct xen_netif_extra_info *) 688 RING_GET_RESPONSE(&np->rx, ++cons); 689 690 if (unlikely(!extra->type || 691 extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) { 692 if (net_ratelimit()) 693 dev_warn(dev, "Invalid extra type: %d\n", 694 extra->type); 695 err = -EINVAL; 696 } else { 697 memcpy(&extras[extra->type - 1], extra, 698 sizeof(*extra)); 699 } 700 701 skb = xennet_get_rx_skb(np, cons); 702 ref = xennet_get_rx_ref(np, cons); 703 xennet_move_rx_slot(np, skb, ref); 704 } while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE); 705 706 np->rx.rsp_cons = cons; 707 return err; 708 } 709 710 static int xennet_get_responses(struct netfront_info *np, 711 struct netfront_rx_info *rinfo, RING_IDX rp, 712 struct sk_buff_head *list) 713 { 714 struct xen_netif_rx_response *rx = &rinfo->rx; 715 struct xen_netif_extra_info *extras = rinfo->extras; 716 struct device *dev = &np->netdev->dev; 717 RING_IDX cons = np->rx.rsp_cons; 718 struct sk_buff *skb = xennet_get_rx_skb(np, cons); 719 grant_ref_t ref = xennet_get_rx_ref(np, cons); 720 int max = MAX_SKB_FRAGS + (rx->status <= RX_COPY_THRESHOLD); 721 int frags = 1; 722 int err = 0; 723 unsigned long ret; 724 725 if (rx->flags & XEN_NETRXF_extra_info) { 726 err = xennet_get_extras(np, extras, rp); 727 cons = np->rx.rsp_cons; 728 } 729 730 for (;;) { 731 if (unlikely(rx->status < 0 || 732 rx->offset + rx->status > PAGE_SIZE)) { 733 if (net_ratelimit()) 734 dev_warn(dev, "rx->offset: %x, size: %u\n", 735 rx->offset, rx->status); 736 xennet_move_rx_slot(np, skb, ref); 737 err = -EINVAL; 738 goto next; 739 } 740 741 /* 742 * This definitely indicates a bug, either in this driver or in 743 * the backend driver. In future this should flag the bad 744 * situation to the system controller to reboot the backed. 745 */ 746 if (ref == GRANT_INVALID_REF) { 747 if (net_ratelimit()) 748 dev_warn(dev, "Bad rx response id %d.\n", 749 rx->id); 750 err = -EINVAL; 751 goto next; 752 } 753 754 ret = gnttab_end_foreign_access_ref(ref, 0); 755 BUG_ON(!ret); 756 757 gnttab_release_grant_reference(&np->gref_rx_head, ref); 758 759 __skb_queue_tail(list, skb); 760 761 next: 762 if (!(rx->flags & XEN_NETRXF_more_data)) 763 break; 764 765 if (cons + frags == rp) { 766 if (net_ratelimit()) 767 dev_warn(dev, "Need more frags\n"); 768 err = -ENOENT; 769 break; 770 } 771 772 rx = RING_GET_RESPONSE(&np->rx, cons + frags); 773 skb = xennet_get_rx_skb(np, cons + frags); 774 ref = xennet_get_rx_ref(np, cons + frags); 775 frags++; 776 } 777 778 if (unlikely(frags > max)) { 779 if (net_ratelimit()) 780 dev_warn(dev, "Too many frags\n"); 781 err = -E2BIG; 782 } 783 784 if (unlikely(err)) 785 np->rx.rsp_cons = cons + frags; 786 787 return err; 788 } 789 790 static int xennet_set_skb_gso(struct sk_buff *skb, 791 struct xen_netif_extra_info *gso) 792 { 793 if (!gso->u.gso.size) { 794 if (net_ratelimit()) 795 printk(KERN_WARNING "GSO size must not be zero.\n"); 796 return -EINVAL; 797 } 798 799 /* Currently only TCPv4 S.O. is supported. */ 800 if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) { 801 if (net_ratelimit()) 802 printk(KERN_WARNING "Bad GSO type %d.\n", gso->u.gso.type); 803 return -EINVAL; 804 } 805 806 skb_shinfo(skb)->gso_size = gso->u.gso.size; 807 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 808 809 /* Header must be checked, and gso_segs computed. */ 810 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 811 skb_shinfo(skb)->gso_segs = 0; 812 813 return 0; 814 } 815 816 static RING_IDX xennet_fill_frags(struct netfront_info *np, 817 struct sk_buff *skb, 818 struct sk_buff_head *list) 819 { 820 struct skb_shared_info *shinfo = skb_shinfo(skb); 821 int nr_frags = shinfo->nr_frags; 822 RING_IDX cons = np->rx.rsp_cons; 823 struct sk_buff *nskb; 824 825 while ((nskb = __skb_dequeue(list))) { 826 struct xen_netif_rx_response *rx = 827 RING_GET_RESPONSE(&np->rx, ++cons); 828 skb_frag_t *nfrag = &skb_shinfo(nskb)->frags[0]; 829 830 __skb_fill_page_desc(skb, nr_frags, 831 skb_frag_page(nfrag), 832 rx->offset, rx->status); 833 834 skb->data_len += rx->status; 835 836 skb_shinfo(nskb)->nr_frags = 0; 837 kfree_skb(nskb); 838 839 nr_frags++; 840 } 841 842 shinfo->nr_frags = nr_frags; 843 return cons; 844 } 845 846 static int checksum_setup(struct net_device *dev, struct sk_buff *skb) 847 { 848 struct iphdr *iph; 849 unsigned char *th; 850 int err = -EPROTO; 851 int recalculate_partial_csum = 0; 852 853 /* 854 * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy 855 * peers can fail to set NETRXF_csum_blank when sending a GSO 856 * frame. In this case force the SKB to CHECKSUM_PARTIAL and 857 * recalculate the partial checksum. 858 */ 859 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) { 860 struct netfront_info *np = netdev_priv(dev); 861 np->rx_gso_checksum_fixup++; 862 skb->ip_summed = CHECKSUM_PARTIAL; 863 recalculate_partial_csum = 1; 864 } 865 866 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */ 867 if (skb->ip_summed != CHECKSUM_PARTIAL) 868 return 0; 869 870 if (skb->protocol != htons(ETH_P_IP)) 871 goto out; 872 873 iph = (void *)skb->data; 874 th = skb->data + 4 * iph->ihl; 875 if (th >= skb_tail_pointer(skb)) 876 goto out; 877 878 skb->csum_start = th - skb->head; 879 switch (iph->protocol) { 880 case IPPROTO_TCP: 881 skb->csum_offset = offsetof(struct tcphdr, check); 882 883 if (recalculate_partial_csum) { 884 struct tcphdr *tcph = (struct tcphdr *)th; 885 tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, 886 skb->len - iph->ihl*4, 887 IPPROTO_TCP, 0); 888 } 889 break; 890 case IPPROTO_UDP: 891 skb->csum_offset = offsetof(struct udphdr, check); 892 893 if (recalculate_partial_csum) { 894 struct udphdr *udph = (struct udphdr *)th; 895 udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, 896 skb->len - iph->ihl*4, 897 IPPROTO_UDP, 0); 898 } 899 break; 900 default: 901 if (net_ratelimit()) 902 printk(KERN_ERR "Attempting to checksum a non-" 903 "TCP/UDP packet, dropping a protocol" 904 " %d packet", iph->protocol); 905 goto out; 906 } 907 908 if ((th + skb->csum_offset + 2) > skb_tail_pointer(skb)) 909 goto out; 910 911 err = 0; 912 913 out: 914 return err; 915 } 916 917 static int handle_incoming_queue(struct net_device *dev, 918 struct sk_buff_head *rxq) 919 { 920 struct netfront_info *np = netdev_priv(dev); 921 struct netfront_stats *stats = this_cpu_ptr(np->stats); 922 int packets_dropped = 0; 923 struct sk_buff *skb; 924 925 while ((skb = __skb_dequeue(rxq)) != NULL) { 926 int pull_to = NETFRONT_SKB_CB(skb)->pull_to; 927 928 __pskb_pull_tail(skb, pull_to - skb_headlen(skb)); 929 930 /* Ethernet work: Delayed to here as it peeks the header. */ 931 skb->protocol = eth_type_trans(skb, dev); 932 933 if (checksum_setup(dev, skb)) { 934 kfree_skb(skb); 935 packets_dropped++; 936 dev->stats.rx_errors++; 937 continue; 938 } 939 940 u64_stats_update_begin(&stats->syncp); 941 stats->rx_packets++; 942 stats->rx_bytes += skb->len; 943 u64_stats_update_end(&stats->syncp); 944 945 /* Pass it up. */ 946 netif_receive_skb(skb); 947 } 948 949 return packets_dropped; 950 } 951 952 static int xennet_poll(struct napi_struct *napi, int budget) 953 { 954 struct netfront_info *np = container_of(napi, struct netfront_info, napi); 955 struct net_device *dev = np->netdev; 956 struct sk_buff *skb; 957 struct netfront_rx_info rinfo; 958 struct xen_netif_rx_response *rx = &rinfo.rx; 959 struct xen_netif_extra_info *extras = rinfo.extras; 960 RING_IDX i, rp; 961 int work_done; 962 struct sk_buff_head rxq; 963 struct sk_buff_head errq; 964 struct sk_buff_head tmpq; 965 unsigned long flags; 966 int err; 967 968 spin_lock(&np->rx_lock); 969 970 skb_queue_head_init(&rxq); 971 skb_queue_head_init(&errq); 972 skb_queue_head_init(&tmpq); 973 974 rp = np->rx.sring->rsp_prod; 975 rmb(); /* Ensure we see queued responses up to 'rp'. */ 976 977 i = np->rx.rsp_cons; 978 work_done = 0; 979 while ((i != rp) && (work_done < budget)) { 980 memcpy(rx, RING_GET_RESPONSE(&np->rx, i), sizeof(*rx)); 981 memset(extras, 0, sizeof(rinfo.extras)); 982 983 err = xennet_get_responses(np, &rinfo, rp, &tmpq); 984 985 if (unlikely(err)) { 986 err: 987 while ((skb = __skb_dequeue(&tmpq))) 988 __skb_queue_tail(&errq, skb); 989 dev->stats.rx_errors++; 990 i = np->rx.rsp_cons; 991 continue; 992 } 993 994 skb = __skb_dequeue(&tmpq); 995 996 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) { 997 struct xen_netif_extra_info *gso; 998 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1]; 999 1000 if (unlikely(xennet_set_skb_gso(skb, gso))) { 1001 __skb_queue_head(&tmpq, skb); 1002 np->rx.rsp_cons += skb_queue_len(&tmpq); 1003 goto err; 1004 } 1005 } 1006 1007 NETFRONT_SKB_CB(skb)->pull_to = rx->status; 1008 if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD) 1009 NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD; 1010 1011 skb_shinfo(skb)->frags[0].page_offset = rx->offset; 1012 skb_frag_size_set(&skb_shinfo(skb)->frags[0], rx->status); 1013 skb->data_len = rx->status; 1014 1015 i = xennet_fill_frags(np, skb, &tmpq); 1016 1017 /* 1018 * Truesize is the actual allocation size, even if the 1019 * allocation is only partially used. 1020 */ 1021 skb->truesize += PAGE_SIZE * skb_shinfo(skb)->nr_frags; 1022 skb->len += skb->data_len; 1023 1024 if (rx->flags & XEN_NETRXF_csum_blank) 1025 skb->ip_summed = CHECKSUM_PARTIAL; 1026 else if (rx->flags & XEN_NETRXF_data_validated) 1027 skb->ip_summed = CHECKSUM_UNNECESSARY; 1028 1029 __skb_queue_tail(&rxq, skb); 1030 1031 np->rx.rsp_cons = ++i; 1032 work_done++; 1033 } 1034 1035 __skb_queue_purge(&errq); 1036 1037 work_done -= handle_incoming_queue(dev, &rxq); 1038 1039 /* If we get a callback with very few responses, reduce fill target. */ 1040 /* NB. Note exponential increase, linear decrease. */ 1041 if (((np->rx.req_prod_pvt - np->rx.sring->rsp_prod) > 1042 ((3*np->rx_target) / 4)) && 1043 (--np->rx_target < np->rx_min_target)) 1044 np->rx_target = np->rx_min_target; 1045 1046 xennet_alloc_rx_buffers(dev); 1047 1048 if (work_done < budget) { 1049 int more_to_do = 0; 1050 1051 local_irq_save(flags); 1052 1053 RING_FINAL_CHECK_FOR_RESPONSES(&np->rx, more_to_do); 1054 if (!more_to_do) 1055 __napi_complete(napi); 1056 1057 local_irq_restore(flags); 1058 } 1059 1060 spin_unlock(&np->rx_lock); 1061 1062 return work_done; 1063 } 1064 1065 static int xennet_change_mtu(struct net_device *dev, int mtu) 1066 { 1067 int max = xennet_can_sg(dev) ? 65535 - ETH_HLEN : ETH_DATA_LEN; 1068 1069 if (mtu > max) 1070 return -EINVAL; 1071 dev->mtu = mtu; 1072 return 0; 1073 } 1074 1075 static struct rtnl_link_stats64 *xennet_get_stats64(struct net_device *dev, 1076 struct rtnl_link_stats64 *tot) 1077 { 1078 struct netfront_info *np = netdev_priv(dev); 1079 int cpu; 1080 1081 for_each_possible_cpu(cpu) { 1082 struct netfront_stats *stats = per_cpu_ptr(np->stats, cpu); 1083 u64 rx_packets, rx_bytes, tx_packets, tx_bytes; 1084 unsigned int start; 1085 1086 do { 1087 start = u64_stats_fetch_begin_bh(&stats->syncp); 1088 1089 rx_packets = stats->rx_packets; 1090 tx_packets = stats->tx_packets; 1091 rx_bytes = stats->rx_bytes; 1092 tx_bytes = stats->tx_bytes; 1093 } while (u64_stats_fetch_retry_bh(&stats->syncp, start)); 1094 1095 tot->rx_packets += rx_packets; 1096 tot->tx_packets += tx_packets; 1097 tot->rx_bytes += rx_bytes; 1098 tot->tx_bytes += tx_bytes; 1099 } 1100 1101 tot->rx_errors = dev->stats.rx_errors; 1102 tot->tx_dropped = dev->stats.tx_dropped; 1103 1104 return tot; 1105 } 1106 1107 static void xennet_release_tx_bufs(struct netfront_info *np) 1108 { 1109 struct sk_buff *skb; 1110 int i; 1111 1112 for (i = 0; i < NET_TX_RING_SIZE; i++) { 1113 /* Skip over entries which are actually freelist references */ 1114 if (skb_entry_is_link(&np->tx_skbs[i])) 1115 continue; 1116 1117 skb = np->tx_skbs[i].skb; 1118 gnttab_end_foreign_access_ref(np->grant_tx_ref[i], 1119 GNTMAP_readonly); 1120 gnttab_release_grant_reference(&np->gref_tx_head, 1121 np->grant_tx_ref[i]); 1122 np->grant_tx_ref[i] = GRANT_INVALID_REF; 1123 add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, i); 1124 dev_kfree_skb_irq(skb); 1125 } 1126 } 1127 1128 static void xennet_release_rx_bufs(struct netfront_info *np) 1129 { 1130 struct mmu_update *mmu = np->rx_mmu; 1131 struct multicall_entry *mcl = np->rx_mcl; 1132 struct sk_buff_head free_list; 1133 struct sk_buff *skb; 1134 unsigned long mfn; 1135 int xfer = 0, noxfer = 0, unused = 0; 1136 int id, ref; 1137 1138 dev_warn(&np->netdev->dev, "%s: fix me for copying receiver.\n", 1139 __func__); 1140 return; 1141 1142 skb_queue_head_init(&free_list); 1143 1144 spin_lock_bh(&np->rx_lock); 1145 1146 for (id = 0; id < NET_RX_RING_SIZE; id++) { 1147 ref = np->grant_rx_ref[id]; 1148 if (ref == GRANT_INVALID_REF) { 1149 unused++; 1150 continue; 1151 } 1152 1153 skb = np->rx_skbs[id]; 1154 mfn = gnttab_end_foreign_transfer_ref(ref); 1155 gnttab_release_grant_reference(&np->gref_rx_head, ref); 1156 np->grant_rx_ref[id] = GRANT_INVALID_REF; 1157 1158 if (0 == mfn) { 1159 skb_shinfo(skb)->nr_frags = 0; 1160 dev_kfree_skb(skb); 1161 noxfer++; 1162 continue; 1163 } 1164 1165 if (!xen_feature(XENFEAT_auto_translated_physmap)) { 1166 /* Remap the page. */ 1167 const struct page *page = 1168 skb_frag_page(&skb_shinfo(skb)->frags[0]); 1169 unsigned long pfn = page_to_pfn(page); 1170 void *vaddr = page_address(page); 1171 1172 MULTI_update_va_mapping(mcl, (unsigned long)vaddr, 1173 mfn_pte(mfn, PAGE_KERNEL), 1174 0); 1175 mcl++; 1176 mmu->ptr = ((u64)mfn << PAGE_SHIFT) 1177 | MMU_MACHPHYS_UPDATE; 1178 mmu->val = pfn; 1179 mmu++; 1180 1181 set_phys_to_machine(pfn, mfn); 1182 } 1183 __skb_queue_tail(&free_list, skb); 1184 xfer++; 1185 } 1186 1187 dev_info(&np->netdev->dev, "%s: %d xfer, %d noxfer, %d unused\n", 1188 __func__, xfer, noxfer, unused); 1189 1190 if (xfer) { 1191 if (!xen_feature(XENFEAT_auto_translated_physmap)) { 1192 /* Do all the remapping work and M2P updates. */ 1193 MULTI_mmu_update(mcl, np->rx_mmu, mmu - np->rx_mmu, 1194 NULL, DOMID_SELF); 1195 mcl++; 1196 HYPERVISOR_multicall(np->rx_mcl, mcl - np->rx_mcl); 1197 } 1198 } 1199 1200 __skb_queue_purge(&free_list); 1201 1202 spin_unlock_bh(&np->rx_lock); 1203 } 1204 1205 static void xennet_uninit(struct net_device *dev) 1206 { 1207 struct netfront_info *np = netdev_priv(dev); 1208 xennet_release_tx_bufs(np); 1209 xennet_release_rx_bufs(np); 1210 gnttab_free_grant_references(np->gref_tx_head); 1211 gnttab_free_grant_references(np->gref_rx_head); 1212 } 1213 1214 static netdev_features_t xennet_fix_features(struct net_device *dev, 1215 netdev_features_t features) 1216 { 1217 struct netfront_info *np = netdev_priv(dev); 1218 int val; 1219 1220 if (features & NETIF_F_SG) { 1221 if (xenbus_scanf(XBT_NIL, np->xbdev->otherend, "feature-sg", 1222 "%d", &val) < 0) 1223 val = 0; 1224 1225 if (!val) 1226 features &= ~NETIF_F_SG; 1227 } 1228 1229 if (features & NETIF_F_TSO) { 1230 if (xenbus_scanf(XBT_NIL, np->xbdev->otherend, 1231 "feature-gso-tcpv4", "%d", &val) < 0) 1232 val = 0; 1233 1234 if (!val) 1235 features &= ~NETIF_F_TSO; 1236 } 1237 1238 return features; 1239 } 1240 1241 static int xennet_set_features(struct net_device *dev, 1242 netdev_features_t features) 1243 { 1244 if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN) { 1245 netdev_info(dev, "Reducing MTU because no SG offload"); 1246 dev->mtu = ETH_DATA_LEN; 1247 } 1248 1249 return 0; 1250 } 1251 1252 static irqreturn_t xennet_interrupt(int irq, void *dev_id) 1253 { 1254 struct net_device *dev = dev_id; 1255 struct netfront_info *np = netdev_priv(dev); 1256 unsigned long flags; 1257 1258 spin_lock_irqsave(&np->tx_lock, flags); 1259 1260 if (likely(netif_carrier_ok(dev))) { 1261 xennet_tx_buf_gc(dev); 1262 /* Under tx_lock: protects access to rx shared-ring indexes. */ 1263 if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx)) 1264 napi_schedule(&np->napi); 1265 } 1266 1267 spin_unlock_irqrestore(&np->tx_lock, flags); 1268 1269 return IRQ_HANDLED; 1270 } 1271 1272 #ifdef CONFIG_NET_POLL_CONTROLLER 1273 static void xennet_poll_controller(struct net_device *dev) 1274 { 1275 xennet_interrupt(0, dev); 1276 } 1277 #endif 1278 1279 static const struct net_device_ops xennet_netdev_ops = { 1280 .ndo_open = xennet_open, 1281 .ndo_uninit = xennet_uninit, 1282 .ndo_stop = xennet_close, 1283 .ndo_start_xmit = xennet_start_xmit, 1284 .ndo_change_mtu = xennet_change_mtu, 1285 .ndo_get_stats64 = xennet_get_stats64, 1286 .ndo_set_mac_address = eth_mac_addr, 1287 .ndo_validate_addr = eth_validate_addr, 1288 .ndo_fix_features = xennet_fix_features, 1289 .ndo_set_features = xennet_set_features, 1290 #ifdef CONFIG_NET_POLL_CONTROLLER 1291 .ndo_poll_controller = xennet_poll_controller, 1292 #endif 1293 }; 1294 1295 static struct net_device *xennet_create_dev(struct xenbus_device *dev) 1296 { 1297 int i, err; 1298 struct net_device *netdev; 1299 struct netfront_info *np; 1300 1301 netdev = alloc_etherdev(sizeof(struct netfront_info)); 1302 if (!netdev) 1303 return ERR_PTR(-ENOMEM); 1304 1305 np = netdev_priv(netdev); 1306 np->xbdev = dev; 1307 1308 spin_lock_init(&np->tx_lock); 1309 spin_lock_init(&np->rx_lock); 1310 1311 skb_queue_head_init(&np->rx_batch); 1312 np->rx_target = RX_DFL_MIN_TARGET; 1313 np->rx_min_target = RX_DFL_MIN_TARGET; 1314 np->rx_max_target = RX_MAX_TARGET; 1315 1316 init_timer(&np->rx_refill_timer); 1317 np->rx_refill_timer.data = (unsigned long)netdev; 1318 np->rx_refill_timer.function = rx_refill_timeout; 1319 1320 err = -ENOMEM; 1321 np->stats = alloc_percpu(struct netfront_stats); 1322 if (np->stats == NULL) 1323 goto exit; 1324 1325 /* Initialise tx_skbs as a free chain containing every entry. */ 1326 np->tx_skb_freelist = 0; 1327 for (i = 0; i < NET_TX_RING_SIZE; i++) { 1328 skb_entry_set_link(&np->tx_skbs[i], i+1); 1329 np->grant_tx_ref[i] = GRANT_INVALID_REF; 1330 } 1331 1332 /* Clear out rx_skbs */ 1333 for (i = 0; i < NET_RX_RING_SIZE; i++) { 1334 np->rx_skbs[i] = NULL; 1335 np->grant_rx_ref[i] = GRANT_INVALID_REF; 1336 } 1337 1338 /* A grant for every tx ring slot */ 1339 if (gnttab_alloc_grant_references(TX_MAX_TARGET, 1340 &np->gref_tx_head) < 0) { 1341 printk(KERN_ALERT "#### netfront can't alloc tx grant refs\n"); 1342 err = -ENOMEM; 1343 goto exit_free_stats; 1344 } 1345 /* A grant for every rx ring slot */ 1346 if (gnttab_alloc_grant_references(RX_MAX_TARGET, 1347 &np->gref_rx_head) < 0) { 1348 printk(KERN_ALERT "#### netfront can't alloc rx grant refs\n"); 1349 err = -ENOMEM; 1350 goto exit_free_tx; 1351 } 1352 1353 netdev->netdev_ops = &xennet_netdev_ops; 1354 1355 netif_napi_add(netdev, &np->napi, xennet_poll, 64); 1356 netdev->features = NETIF_F_IP_CSUM | NETIF_F_RXCSUM | 1357 NETIF_F_GSO_ROBUST; 1358 netdev->hw_features = NETIF_F_IP_CSUM | NETIF_F_SG | NETIF_F_TSO; 1359 1360 /* 1361 * Assume that all hw features are available for now. This set 1362 * will be adjusted by the call to netdev_update_features() in 1363 * xennet_connect() which is the earliest point where we can 1364 * negotiate with the backend regarding supported features. 1365 */ 1366 netdev->features |= netdev->hw_features; 1367 1368 SET_ETHTOOL_OPS(netdev, &xennet_ethtool_ops); 1369 SET_NETDEV_DEV(netdev, &dev->dev); 1370 1371 np->netdev = netdev; 1372 1373 netif_carrier_off(netdev); 1374 1375 return netdev; 1376 1377 exit_free_tx: 1378 gnttab_free_grant_references(np->gref_tx_head); 1379 exit_free_stats: 1380 free_percpu(np->stats); 1381 exit: 1382 free_netdev(netdev); 1383 return ERR_PTR(err); 1384 } 1385 1386 /** 1387 * Entry point to this code when a new device is created. Allocate the basic 1388 * structures and the ring buffers for communication with the backend, and 1389 * inform the backend of the appropriate details for those. 1390 */ 1391 static int netfront_probe(struct xenbus_device *dev, 1392 const struct xenbus_device_id *id) 1393 { 1394 int err; 1395 struct net_device *netdev; 1396 struct netfront_info *info; 1397 1398 netdev = xennet_create_dev(dev); 1399 if (IS_ERR(netdev)) { 1400 err = PTR_ERR(netdev); 1401 xenbus_dev_fatal(dev, err, "creating netdev"); 1402 return err; 1403 } 1404 1405 info = netdev_priv(netdev); 1406 dev_set_drvdata(&dev->dev, info); 1407 1408 err = register_netdev(info->netdev); 1409 if (err) { 1410 printk(KERN_WARNING "%s: register_netdev err=%d\n", 1411 __func__, err); 1412 goto fail; 1413 } 1414 1415 err = xennet_sysfs_addif(info->netdev); 1416 if (err) { 1417 unregister_netdev(info->netdev); 1418 printk(KERN_WARNING "%s: add sysfs failed err=%d\n", 1419 __func__, err); 1420 goto fail; 1421 } 1422 1423 return 0; 1424 1425 fail: 1426 free_netdev(netdev); 1427 dev_set_drvdata(&dev->dev, NULL); 1428 return err; 1429 } 1430 1431 static void xennet_end_access(int ref, void *page) 1432 { 1433 /* This frees the page as a side-effect */ 1434 if (ref != GRANT_INVALID_REF) 1435 gnttab_end_foreign_access(ref, 0, (unsigned long)page); 1436 } 1437 1438 static void xennet_disconnect_backend(struct netfront_info *info) 1439 { 1440 /* Stop old i/f to prevent errors whilst we rebuild the state. */ 1441 spin_lock_bh(&info->rx_lock); 1442 spin_lock_irq(&info->tx_lock); 1443 netif_carrier_off(info->netdev); 1444 spin_unlock_irq(&info->tx_lock); 1445 spin_unlock_bh(&info->rx_lock); 1446 1447 if (info->netdev->irq) 1448 unbind_from_irqhandler(info->netdev->irq, info->netdev); 1449 info->evtchn = info->netdev->irq = 0; 1450 1451 /* End access and free the pages */ 1452 xennet_end_access(info->tx_ring_ref, info->tx.sring); 1453 xennet_end_access(info->rx_ring_ref, info->rx.sring); 1454 1455 info->tx_ring_ref = GRANT_INVALID_REF; 1456 info->rx_ring_ref = GRANT_INVALID_REF; 1457 info->tx.sring = NULL; 1458 info->rx.sring = NULL; 1459 } 1460 1461 /** 1462 * We are reconnecting to the backend, due to a suspend/resume, or a backend 1463 * driver restart. We tear down our netif structure and recreate it, but 1464 * leave the device-layer structures intact so that this is transparent to the 1465 * rest of the kernel. 1466 */ 1467 static int netfront_resume(struct xenbus_device *dev) 1468 { 1469 struct netfront_info *info = dev_get_drvdata(&dev->dev); 1470 1471 dev_dbg(&dev->dev, "%s\n", dev->nodename); 1472 1473 xennet_disconnect_backend(info); 1474 return 0; 1475 } 1476 1477 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[]) 1478 { 1479 char *s, *e, *macstr; 1480 int i; 1481 1482 macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL); 1483 if (IS_ERR(macstr)) 1484 return PTR_ERR(macstr); 1485 1486 for (i = 0; i < ETH_ALEN; i++) { 1487 mac[i] = simple_strtoul(s, &e, 16); 1488 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) { 1489 kfree(macstr); 1490 return -ENOENT; 1491 } 1492 s = e+1; 1493 } 1494 1495 kfree(macstr); 1496 return 0; 1497 } 1498 1499 static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info) 1500 { 1501 struct xen_netif_tx_sring *txs; 1502 struct xen_netif_rx_sring *rxs; 1503 int err; 1504 struct net_device *netdev = info->netdev; 1505 1506 info->tx_ring_ref = GRANT_INVALID_REF; 1507 info->rx_ring_ref = GRANT_INVALID_REF; 1508 info->rx.sring = NULL; 1509 info->tx.sring = NULL; 1510 netdev->irq = 0; 1511 1512 err = xen_net_read_mac(dev, netdev->dev_addr); 1513 if (err) { 1514 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename); 1515 goto fail; 1516 } 1517 1518 txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH); 1519 if (!txs) { 1520 err = -ENOMEM; 1521 xenbus_dev_fatal(dev, err, "allocating tx ring page"); 1522 goto fail; 1523 } 1524 SHARED_RING_INIT(txs); 1525 FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE); 1526 1527 err = xenbus_grant_ring(dev, virt_to_mfn(txs)); 1528 if (err < 0) { 1529 free_page((unsigned long)txs); 1530 goto fail; 1531 } 1532 1533 info->tx_ring_ref = err; 1534 rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH); 1535 if (!rxs) { 1536 err = -ENOMEM; 1537 xenbus_dev_fatal(dev, err, "allocating rx ring page"); 1538 goto fail; 1539 } 1540 SHARED_RING_INIT(rxs); 1541 FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE); 1542 1543 err = xenbus_grant_ring(dev, virt_to_mfn(rxs)); 1544 if (err < 0) { 1545 free_page((unsigned long)rxs); 1546 goto fail; 1547 } 1548 info->rx_ring_ref = err; 1549 1550 err = xenbus_alloc_evtchn(dev, &info->evtchn); 1551 if (err) 1552 goto fail; 1553 1554 err = bind_evtchn_to_irqhandler(info->evtchn, xennet_interrupt, 1555 0, netdev->name, netdev); 1556 if (err < 0) 1557 goto fail; 1558 netdev->irq = err; 1559 return 0; 1560 1561 fail: 1562 return err; 1563 } 1564 1565 /* Common code used when first setting up, and when resuming. */ 1566 static int talk_to_netback(struct xenbus_device *dev, 1567 struct netfront_info *info) 1568 { 1569 const char *message; 1570 struct xenbus_transaction xbt; 1571 int err; 1572 1573 /* Create shared ring, alloc event channel. */ 1574 err = setup_netfront(dev, info); 1575 if (err) 1576 goto out; 1577 1578 again: 1579 err = xenbus_transaction_start(&xbt); 1580 if (err) { 1581 xenbus_dev_fatal(dev, err, "starting transaction"); 1582 goto destroy_ring; 1583 } 1584 1585 err = xenbus_printf(xbt, dev->nodename, "tx-ring-ref", "%u", 1586 info->tx_ring_ref); 1587 if (err) { 1588 message = "writing tx ring-ref"; 1589 goto abort_transaction; 1590 } 1591 err = xenbus_printf(xbt, dev->nodename, "rx-ring-ref", "%u", 1592 info->rx_ring_ref); 1593 if (err) { 1594 message = "writing rx ring-ref"; 1595 goto abort_transaction; 1596 } 1597 err = xenbus_printf(xbt, dev->nodename, 1598 "event-channel", "%u", info->evtchn); 1599 if (err) { 1600 message = "writing event-channel"; 1601 goto abort_transaction; 1602 } 1603 1604 err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u", 1605 1); 1606 if (err) { 1607 message = "writing request-rx-copy"; 1608 goto abort_transaction; 1609 } 1610 1611 err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1); 1612 if (err) { 1613 message = "writing feature-rx-notify"; 1614 goto abort_transaction; 1615 } 1616 1617 err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1); 1618 if (err) { 1619 message = "writing feature-sg"; 1620 goto abort_transaction; 1621 } 1622 1623 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1); 1624 if (err) { 1625 message = "writing feature-gso-tcpv4"; 1626 goto abort_transaction; 1627 } 1628 1629 err = xenbus_transaction_end(xbt, 0); 1630 if (err) { 1631 if (err == -EAGAIN) 1632 goto again; 1633 xenbus_dev_fatal(dev, err, "completing transaction"); 1634 goto destroy_ring; 1635 } 1636 1637 return 0; 1638 1639 abort_transaction: 1640 xenbus_transaction_end(xbt, 1); 1641 xenbus_dev_fatal(dev, err, "%s", message); 1642 destroy_ring: 1643 xennet_disconnect_backend(info); 1644 out: 1645 return err; 1646 } 1647 1648 static int xennet_connect(struct net_device *dev) 1649 { 1650 struct netfront_info *np = netdev_priv(dev); 1651 int i, requeue_idx, err; 1652 struct sk_buff *skb; 1653 grant_ref_t ref; 1654 struct xen_netif_rx_request *req; 1655 unsigned int feature_rx_copy; 1656 1657 err = xenbus_scanf(XBT_NIL, np->xbdev->otherend, 1658 "feature-rx-copy", "%u", &feature_rx_copy); 1659 if (err != 1) 1660 feature_rx_copy = 0; 1661 1662 if (!feature_rx_copy) { 1663 dev_info(&dev->dev, 1664 "backend does not support copying receive path\n"); 1665 return -ENODEV; 1666 } 1667 1668 err = talk_to_netback(np->xbdev, np); 1669 if (err) 1670 return err; 1671 1672 rtnl_lock(); 1673 netdev_update_features(dev); 1674 rtnl_unlock(); 1675 1676 spin_lock_bh(&np->rx_lock); 1677 spin_lock_irq(&np->tx_lock); 1678 1679 /* Step 1: Discard all pending TX packet fragments. */ 1680 xennet_release_tx_bufs(np); 1681 1682 /* Step 2: Rebuild the RX buffer freelist and the RX ring itself. */ 1683 for (requeue_idx = 0, i = 0; i < NET_RX_RING_SIZE; i++) { 1684 skb_frag_t *frag; 1685 const struct page *page; 1686 if (!np->rx_skbs[i]) 1687 continue; 1688 1689 skb = np->rx_skbs[requeue_idx] = xennet_get_rx_skb(np, i); 1690 ref = np->grant_rx_ref[requeue_idx] = xennet_get_rx_ref(np, i); 1691 req = RING_GET_REQUEST(&np->rx, requeue_idx); 1692 1693 frag = &skb_shinfo(skb)->frags[0]; 1694 page = skb_frag_page(frag); 1695 gnttab_grant_foreign_access_ref( 1696 ref, np->xbdev->otherend_id, 1697 pfn_to_mfn(page_to_pfn(page)), 1698 0); 1699 req->gref = ref; 1700 req->id = requeue_idx; 1701 1702 requeue_idx++; 1703 } 1704 1705 np->rx.req_prod_pvt = requeue_idx; 1706 1707 /* 1708 * Step 3: All public and private state should now be sane. Get 1709 * ready to start sending and receiving packets and give the driver 1710 * domain a kick because we've probably just requeued some 1711 * packets. 1712 */ 1713 netif_carrier_on(np->netdev); 1714 notify_remote_via_irq(np->netdev->irq); 1715 xennet_tx_buf_gc(dev); 1716 xennet_alloc_rx_buffers(dev); 1717 1718 spin_unlock_irq(&np->tx_lock); 1719 spin_unlock_bh(&np->rx_lock); 1720 1721 return 0; 1722 } 1723 1724 /** 1725 * Callback received when the backend's state changes. 1726 */ 1727 static void netback_changed(struct xenbus_device *dev, 1728 enum xenbus_state backend_state) 1729 { 1730 struct netfront_info *np = dev_get_drvdata(&dev->dev); 1731 struct net_device *netdev = np->netdev; 1732 1733 dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state)); 1734 1735 switch (backend_state) { 1736 case XenbusStateInitialising: 1737 case XenbusStateInitialised: 1738 case XenbusStateReconfiguring: 1739 case XenbusStateReconfigured: 1740 case XenbusStateUnknown: 1741 case XenbusStateClosed: 1742 break; 1743 1744 case XenbusStateInitWait: 1745 if (dev->state != XenbusStateInitialising) 1746 break; 1747 if (xennet_connect(netdev) != 0) 1748 break; 1749 xenbus_switch_state(dev, XenbusStateConnected); 1750 break; 1751 1752 case XenbusStateConnected: 1753 netdev_notify_peers(netdev); 1754 break; 1755 1756 case XenbusStateClosing: 1757 xenbus_frontend_closed(dev); 1758 break; 1759 } 1760 } 1761 1762 static const struct xennet_stat { 1763 char name[ETH_GSTRING_LEN]; 1764 u16 offset; 1765 } xennet_stats[] = { 1766 { 1767 "rx_gso_checksum_fixup", 1768 offsetof(struct netfront_info, rx_gso_checksum_fixup) 1769 }, 1770 }; 1771 1772 static int xennet_get_sset_count(struct net_device *dev, int string_set) 1773 { 1774 switch (string_set) { 1775 case ETH_SS_STATS: 1776 return ARRAY_SIZE(xennet_stats); 1777 default: 1778 return -EINVAL; 1779 } 1780 } 1781 1782 static void xennet_get_ethtool_stats(struct net_device *dev, 1783 struct ethtool_stats *stats, u64 * data) 1784 { 1785 void *np = netdev_priv(dev); 1786 int i; 1787 1788 for (i = 0; i < ARRAY_SIZE(xennet_stats); i++) 1789 data[i] = *(unsigned long *)(np + xennet_stats[i].offset); 1790 } 1791 1792 static void xennet_get_strings(struct net_device *dev, u32 stringset, u8 * data) 1793 { 1794 int i; 1795 1796 switch (stringset) { 1797 case ETH_SS_STATS: 1798 for (i = 0; i < ARRAY_SIZE(xennet_stats); i++) 1799 memcpy(data + i * ETH_GSTRING_LEN, 1800 xennet_stats[i].name, ETH_GSTRING_LEN); 1801 break; 1802 } 1803 } 1804 1805 static const struct ethtool_ops xennet_ethtool_ops = 1806 { 1807 .get_link = ethtool_op_get_link, 1808 1809 .get_sset_count = xennet_get_sset_count, 1810 .get_ethtool_stats = xennet_get_ethtool_stats, 1811 .get_strings = xennet_get_strings, 1812 }; 1813 1814 #ifdef CONFIG_SYSFS 1815 static ssize_t show_rxbuf_min(struct device *dev, 1816 struct device_attribute *attr, char *buf) 1817 { 1818 struct net_device *netdev = to_net_dev(dev); 1819 struct netfront_info *info = netdev_priv(netdev); 1820 1821 return sprintf(buf, "%u\n", info->rx_min_target); 1822 } 1823 1824 static ssize_t store_rxbuf_min(struct device *dev, 1825 struct device_attribute *attr, 1826 const char *buf, size_t len) 1827 { 1828 struct net_device *netdev = to_net_dev(dev); 1829 struct netfront_info *np = netdev_priv(netdev); 1830 char *endp; 1831 unsigned long target; 1832 1833 if (!capable(CAP_NET_ADMIN)) 1834 return -EPERM; 1835 1836 target = simple_strtoul(buf, &endp, 0); 1837 if (endp == buf) 1838 return -EBADMSG; 1839 1840 if (target < RX_MIN_TARGET) 1841 target = RX_MIN_TARGET; 1842 if (target > RX_MAX_TARGET) 1843 target = RX_MAX_TARGET; 1844 1845 spin_lock_bh(&np->rx_lock); 1846 if (target > np->rx_max_target) 1847 np->rx_max_target = target; 1848 np->rx_min_target = target; 1849 if (target > np->rx_target) 1850 np->rx_target = target; 1851 1852 xennet_alloc_rx_buffers(netdev); 1853 1854 spin_unlock_bh(&np->rx_lock); 1855 return len; 1856 } 1857 1858 static ssize_t show_rxbuf_max(struct device *dev, 1859 struct device_attribute *attr, char *buf) 1860 { 1861 struct net_device *netdev = to_net_dev(dev); 1862 struct netfront_info *info = netdev_priv(netdev); 1863 1864 return sprintf(buf, "%u\n", info->rx_max_target); 1865 } 1866 1867 static ssize_t store_rxbuf_max(struct device *dev, 1868 struct device_attribute *attr, 1869 const char *buf, size_t len) 1870 { 1871 struct net_device *netdev = to_net_dev(dev); 1872 struct netfront_info *np = netdev_priv(netdev); 1873 char *endp; 1874 unsigned long target; 1875 1876 if (!capable(CAP_NET_ADMIN)) 1877 return -EPERM; 1878 1879 target = simple_strtoul(buf, &endp, 0); 1880 if (endp == buf) 1881 return -EBADMSG; 1882 1883 if (target < RX_MIN_TARGET) 1884 target = RX_MIN_TARGET; 1885 if (target > RX_MAX_TARGET) 1886 target = RX_MAX_TARGET; 1887 1888 spin_lock_bh(&np->rx_lock); 1889 if (target < np->rx_min_target) 1890 np->rx_min_target = target; 1891 np->rx_max_target = target; 1892 if (target < np->rx_target) 1893 np->rx_target = target; 1894 1895 xennet_alloc_rx_buffers(netdev); 1896 1897 spin_unlock_bh(&np->rx_lock); 1898 return len; 1899 } 1900 1901 static ssize_t show_rxbuf_cur(struct device *dev, 1902 struct device_attribute *attr, char *buf) 1903 { 1904 struct net_device *netdev = to_net_dev(dev); 1905 struct netfront_info *info = netdev_priv(netdev); 1906 1907 return sprintf(buf, "%u\n", info->rx_target); 1908 } 1909 1910 static struct device_attribute xennet_attrs[] = { 1911 __ATTR(rxbuf_min, S_IRUGO|S_IWUSR, show_rxbuf_min, store_rxbuf_min), 1912 __ATTR(rxbuf_max, S_IRUGO|S_IWUSR, show_rxbuf_max, store_rxbuf_max), 1913 __ATTR(rxbuf_cur, S_IRUGO, show_rxbuf_cur, NULL), 1914 }; 1915 1916 static int xennet_sysfs_addif(struct net_device *netdev) 1917 { 1918 int i; 1919 int err; 1920 1921 for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++) { 1922 err = device_create_file(&netdev->dev, 1923 &xennet_attrs[i]); 1924 if (err) 1925 goto fail; 1926 } 1927 return 0; 1928 1929 fail: 1930 while (--i >= 0) 1931 device_remove_file(&netdev->dev, &xennet_attrs[i]); 1932 return err; 1933 } 1934 1935 static void xennet_sysfs_delif(struct net_device *netdev) 1936 { 1937 int i; 1938 1939 for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++) 1940 device_remove_file(&netdev->dev, &xennet_attrs[i]); 1941 } 1942 1943 #endif /* CONFIG_SYSFS */ 1944 1945 static const struct xenbus_device_id netfront_ids[] = { 1946 { "vif" }, 1947 { "" } 1948 }; 1949 1950 1951 static int xennet_remove(struct xenbus_device *dev) 1952 { 1953 struct netfront_info *info = dev_get_drvdata(&dev->dev); 1954 1955 dev_dbg(&dev->dev, "%s\n", dev->nodename); 1956 1957 xennet_disconnect_backend(info); 1958 1959 xennet_sysfs_delif(info->netdev); 1960 1961 unregister_netdev(info->netdev); 1962 1963 del_timer_sync(&info->rx_refill_timer); 1964 1965 free_percpu(info->stats); 1966 1967 free_netdev(info->netdev); 1968 1969 return 0; 1970 } 1971 1972 static DEFINE_XENBUS_DRIVER(netfront, , 1973 .probe = netfront_probe, 1974 .remove = xennet_remove, 1975 .resume = netfront_resume, 1976 .otherend_changed = netback_changed, 1977 ); 1978 1979 static int __init netif_init(void) 1980 { 1981 if (!xen_domain()) 1982 return -ENODEV; 1983 1984 if (xen_hvm_domain() && !xen_platform_pci_unplug) 1985 return -ENODEV; 1986 1987 printk(KERN_INFO "Initialising Xen virtual ethernet driver.\n"); 1988 1989 return xenbus_register_frontend(&netfront_driver); 1990 } 1991 module_init(netif_init); 1992 1993 1994 static void __exit netif_exit(void) 1995 { 1996 xenbus_unregister_driver(&netfront_driver); 1997 } 1998 module_exit(netif_exit); 1999 2000 MODULE_DESCRIPTION("Xen virtual network device frontend"); 2001 MODULE_LICENSE("GPL"); 2002 MODULE_ALIAS("xen:vif"); 2003 MODULE_ALIAS("xennet"); 2004