1 /* 2 * Back-end of the driver for virtual network devices. This portion of the 3 * driver exports a 'unified' network-device interface that can be accessed 4 * by any operating system that implements a compatible front end. A 5 * reference front-end implementation can be found in: 6 * drivers/net/xen-netfront.c 7 * 8 * Copyright (c) 2002-2005, K A Fraser 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License version 2 12 * as published by the Free Software Foundation; or, when distributed 13 * separately from the Linux kernel or incorporated into other 14 * software packages, subject to the following license: 15 * 16 * Permission is hereby granted, free of charge, to any person obtaining a copy 17 * of this source file (the "Software"), to deal in the Software without 18 * restriction, including without limitation the rights to use, copy, modify, 19 * merge, publish, distribute, sublicense, and/or sell copies of the Software, 20 * and to permit persons to whom the Software is furnished to do so, subject to 21 * the following conditions: 22 * 23 * The above copyright notice and this permission notice shall be included in 24 * all copies or substantial portions of the Software. 25 * 26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 28 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 29 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 30 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 31 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 32 * IN THE SOFTWARE. 33 */ 34 35 #include "common.h" 36 37 #include <linux/kthread.h> 38 #include <linux/if_vlan.h> 39 #include <linux/udp.h> 40 #include <linux/highmem.h> 41 42 #include <net/tcp.h> 43 44 #include <xen/xen.h> 45 #include <xen/events.h> 46 #include <xen/interface/memory.h> 47 #include <xen/page.h> 48 49 #include <asm/xen/hypercall.h> 50 51 /* Provide an option to disable split event channels at load time as 52 * event channels are limited resource. Split event channels are 53 * enabled by default. 54 */ 55 bool separate_tx_rx_irq = true; 56 module_param(separate_tx_rx_irq, bool, 0644); 57 58 /* The time that packets can stay on the guest Rx internal queue 59 * before they are dropped. 60 */ 61 unsigned int rx_drain_timeout_msecs = 10000; 62 module_param(rx_drain_timeout_msecs, uint, 0444); 63 64 /* The length of time before the frontend is considered unresponsive 65 * because it isn't providing Rx slots. 66 */ 67 unsigned int rx_stall_timeout_msecs = 60000; 68 module_param(rx_stall_timeout_msecs, uint, 0444); 69 70 unsigned int xenvif_max_queues; 71 module_param_named(max_queues, xenvif_max_queues, uint, 0644); 72 MODULE_PARM_DESC(max_queues, 73 "Maximum number of queues per virtual interface"); 74 75 /* 76 * This is the maximum slots a skb can have. If a guest sends a skb 77 * which exceeds this limit it is considered malicious. 78 */ 79 #define FATAL_SKB_SLOTS_DEFAULT 20 80 static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT; 81 module_param(fatal_skb_slots, uint, 0444); 82 83 /* The amount to copy out of the first guest Tx slot into the skb's 84 * linear area. If the first slot has more data, it will be mapped 85 * and put into the first frag. 86 * 87 * This is sized to avoid pulling headers from the frags for most 88 * TCP/IP packets. 89 */ 90 #define XEN_NETBACK_TX_COPY_LEN 128 91 92 93 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, 94 u8 status); 95 96 static void make_tx_response(struct xenvif_queue *queue, 97 struct xen_netif_tx_request *txp, 98 s8 st); 99 static void push_tx_responses(struct xenvif_queue *queue); 100 101 static inline int tx_work_todo(struct xenvif_queue *queue); 102 103 static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue, 104 u16 id, 105 s8 st, 106 u16 offset, 107 u16 size, 108 u16 flags); 109 110 static inline unsigned long idx_to_pfn(struct xenvif_queue *queue, 111 u16 idx) 112 { 113 return page_to_pfn(queue->mmap_pages[idx]); 114 } 115 116 static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue, 117 u16 idx) 118 { 119 return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx)); 120 } 121 122 #define callback_param(vif, pending_idx) \ 123 (vif->pending_tx_info[pending_idx].callback_struct) 124 125 /* Find the containing VIF's structure from a pointer in pending_tx_info array 126 */ 127 static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf) 128 { 129 u16 pending_idx = ubuf->desc; 130 struct pending_tx_info *temp = 131 container_of(ubuf, struct pending_tx_info, callback_struct); 132 return container_of(temp - pending_idx, 133 struct xenvif_queue, 134 pending_tx_info[0]); 135 } 136 137 static u16 frag_get_pending_idx(skb_frag_t *frag) 138 { 139 return (u16)frag->page_offset; 140 } 141 142 static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx) 143 { 144 frag->page_offset = pending_idx; 145 } 146 147 static inline pending_ring_idx_t pending_index(unsigned i) 148 { 149 return i & (MAX_PENDING_REQS-1); 150 } 151 152 static int xenvif_rx_ring_slots_needed(struct xenvif *vif) 153 { 154 if (vif->gso_mask) 155 return DIV_ROUND_UP(vif->dev->gso_max_size, XEN_PAGE_SIZE) + 1; 156 else 157 return DIV_ROUND_UP(vif->dev->mtu, XEN_PAGE_SIZE); 158 } 159 160 static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue) 161 { 162 RING_IDX prod, cons; 163 int needed; 164 165 needed = xenvif_rx_ring_slots_needed(queue->vif); 166 167 do { 168 prod = queue->rx.sring->req_prod; 169 cons = queue->rx.req_cons; 170 171 if (prod - cons >= needed) 172 return true; 173 174 queue->rx.sring->req_event = prod + 1; 175 176 /* Make sure event is visible before we check prod 177 * again. 178 */ 179 mb(); 180 } while (queue->rx.sring->req_prod != prod); 181 182 return false; 183 } 184 185 void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb) 186 { 187 unsigned long flags; 188 189 spin_lock_irqsave(&queue->rx_queue.lock, flags); 190 191 __skb_queue_tail(&queue->rx_queue, skb); 192 193 queue->rx_queue_len += skb->len; 194 if (queue->rx_queue_len > queue->rx_queue_max) 195 netif_tx_stop_queue(netdev_get_tx_queue(queue->vif->dev, queue->id)); 196 197 spin_unlock_irqrestore(&queue->rx_queue.lock, flags); 198 } 199 200 static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue) 201 { 202 struct sk_buff *skb; 203 204 spin_lock_irq(&queue->rx_queue.lock); 205 206 skb = __skb_dequeue(&queue->rx_queue); 207 if (skb) 208 queue->rx_queue_len -= skb->len; 209 210 spin_unlock_irq(&queue->rx_queue.lock); 211 212 return skb; 213 } 214 215 static void xenvif_rx_queue_maybe_wake(struct xenvif_queue *queue) 216 { 217 spin_lock_irq(&queue->rx_queue.lock); 218 219 if (queue->rx_queue_len < queue->rx_queue_max) 220 netif_tx_wake_queue(netdev_get_tx_queue(queue->vif->dev, queue->id)); 221 222 spin_unlock_irq(&queue->rx_queue.lock); 223 } 224 225 226 static void xenvif_rx_queue_purge(struct xenvif_queue *queue) 227 { 228 struct sk_buff *skb; 229 while ((skb = xenvif_rx_dequeue(queue)) != NULL) 230 kfree_skb(skb); 231 } 232 233 static void xenvif_rx_queue_drop_expired(struct xenvif_queue *queue) 234 { 235 struct sk_buff *skb; 236 237 for(;;) { 238 skb = skb_peek(&queue->rx_queue); 239 if (!skb) 240 break; 241 if (time_before(jiffies, XENVIF_RX_CB(skb)->expires)) 242 break; 243 xenvif_rx_dequeue(queue); 244 kfree_skb(skb); 245 } 246 } 247 248 struct netrx_pending_operations { 249 unsigned copy_prod, copy_cons; 250 unsigned meta_prod, meta_cons; 251 struct gnttab_copy *copy; 252 struct xenvif_rx_meta *meta; 253 int copy_off; 254 grant_ref_t copy_gref; 255 }; 256 257 static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif_queue *queue, 258 struct netrx_pending_operations *npo) 259 { 260 struct xenvif_rx_meta *meta; 261 struct xen_netif_rx_request req; 262 263 RING_COPY_REQUEST(&queue->rx, queue->rx.req_cons++, &req); 264 265 meta = npo->meta + npo->meta_prod++; 266 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE; 267 meta->gso_size = 0; 268 meta->size = 0; 269 meta->id = req.id; 270 271 npo->copy_off = 0; 272 npo->copy_gref = req.gref; 273 274 return meta; 275 } 276 277 struct gop_frag_copy { 278 struct xenvif_queue *queue; 279 struct netrx_pending_operations *npo; 280 struct xenvif_rx_meta *meta; 281 int head; 282 int gso_type; 283 284 struct page *page; 285 }; 286 287 static void xenvif_setup_copy_gop(unsigned long gfn, 288 unsigned int offset, 289 unsigned int *len, 290 struct gop_frag_copy *info) 291 { 292 struct gnttab_copy *copy_gop; 293 struct xen_page_foreign *foreign; 294 /* Convenient aliases */ 295 struct xenvif_queue *queue = info->queue; 296 struct netrx_pending_operations *npo = info->npo; 297 struct page *page = info->page; 298 299 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET); 300 301 if (npo->copy_off == MAX_BUFFER_OFFSET) 302 info->meta = get_next_rx_buffer(queue, npo); 303 304 if (npo->copy_off + *len > MAX_BUFFER_OFFSET) 305 *len = MAX_BUFFER_OFFSET - npo->copy_off; 306 307 copy_gop = npo->copy + npo->copy_prod++; 308 copy_gop->flags = GNTCOPY_dest_gref; 309 copy_gop->len = *len; 310 311 foreign = xen_page_foreign(page); 312 if (foreign) { 313 copy_gop->source.domid = foreign->domid; 314 copy_gop->source.u.ref = foreign->gref; 315 copy_gop->flags |= GNTCOPY_source_gref; 316 } else { 317 copy_gop->source.domid = DOMID_SELF; 318 copy_gop->source.u.gmfn = gfn; 319 } 320 copy_gop->source.offset = offset; 321 322 copy_gop->dest.domid = queue->vif->domid; 323 copy_gop->dest.offset = npo->copy_off; 324 copy_gop->dest.u.ref = npo->copy_gref; 325 326 npo->copy_off += *len; 327 info->meta->size += *len; 328 329 /* Leave a gap for the GSO descriptor. */ 330 if (info->head && ((1 << info->gso_type) & queue->vif->gso_mask)) 331 queue->rx.req_cons++; 332 333 info->head = 0; /* There must be something in this buffer now */ 334 } 335 336 static void xenvif_gop_frag_copy_grant(unsigned long gfn, 337 unsigned offset, 338 unsigned int len, 339 void *data) 340 { 341 unsigned int bytes; 342 343 while (len) { 344 bytes = len; 345 xenvif_setup_copy_gop(gfn, offset, &bytes, data); 346 offset += bytes; 347 len -= bytes; 348 } 349 } 350 351 /* 352 * Set up the grant operations for this fragment. If it's a flipping 353 * interface, we also set up the unmap request from here. 354 */ 355 static void xenvif_gop_frag_copy(struct xenvif_queue *queue, struct sk_buff *skb, 356 struct netrx_pending_operations *npo, 357 struct page *page, unsigned long size, 358 unsigned long offset, int *head) 359 { 360 struct gop_frag_copy info = { 361 .queue = queue, 362 .npo = npo, 363 .head = *head, 364 .gso_type = XEN_NETIF_GSO_TYPE_NONE, 365 }; 366 unsigned long bytes; 367 368 if (skb_is_gso(skb)) { 369 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) 370 info.gso_type = XEN_NETIF_GSO_TYPE_TCPV4; 371 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) 372 info.gso_type = XEN_NETIF_GSO_TYPE_TCPV6; 373 } 374 375 /* Data must not cross a page boundary. */ 376 BUG_ON(size + offset > PAGE_SIZE<<compound_order(page)); 377 378 info.meta = npo->meta + npo->meta_prod - 1; 379 380 /* Skip unused frames from start of page */ 381 page += offset >> PAGE_SHIFT; 382 offset &= ~PAGE_MASK; 383 384 while (size > 0) { 385 BUG_ON(offset >= PAGE_SIZE); 386 387 bytes = PAGE_SIZE - offset; 388 if (bytes > size) 389 bytes = size; 390 391 info.page = page; 392 gnttab_foreach_grant_in_range(page, offset, bytes, 393 xenvif_gop_frag_copy_grant, 394 &info); 395 size -= bytes; 396 offset = 0; 397 398 /* Next page */ 399 if (size) { 400 BUG_ON(!PageCompound(page)); 401 page++; 402 } 403 } 404 405 *head = info.head; 406 } 407 408 /* 409 * Prepare an SKB to be transmitted to the frontend. 410 * 411 * This function is responsible for allocating grant operations, meta 412 * structures, etc. 413 * 414 * It returns the number of meta structures consumed. The number of 415 * ring slots used is always equal to the number of meta slots used 416 * plus the number of GSO descriptors used. Currently, we use either 417 * zero GSO descriptors (for non-GSO packets) or one descriptor (for 418 * frontend-side LRO). 419 */ 420 static int xenvif_gop_skb(struct sk_buff *skb, 421 struct netrx_pending_operations *npo, 422 struct xenvif_queue *queue) 423 { 424 struct xenvif *vif = netdev_priv(skb->dev); 425 int nr_frags = skb_shinfo(skb)->nr_frags; 426 int i; 427 struct xen_netif_rx_request req; 428 struct xenvif_rx_meta *meta; 429 unsigned char *data; 430 int head = 1; 431 int old_meta_prod; 432 int gso_type; 433 434 old_meta_prod = npo->meta_prod; 435 436 gso_type = XEN_NETIF_GSO_TYPE_NONE; 437 if (skb_is_gso(skb)) { 438 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) 439 gso_type = XEN_NETIF_GSO_TYPE_TCPV4; 440 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) 441 gso_type = XEN_NETIF_GSO_TYPE_TCPV6; 442 } 443 444 /* Set up a GSO prefix descriptor, if necessary */ 445 if ((1 << gso_type) & vif->gso_prefix_mask) { 446 RING_COPY_REQUEST(&queue->rx, queue->rx.req_cons++, &req); 447 meta = npo->meta + npo->meta_prod++; 448 meta->gso_type = gso_type; 449 meta->gso_size = skb_shinfo(skb)->gso_size; 450 meta->size = 0; 451 meta->id = req.id; 452 } 453 454 RING_COPY_REQUEST(&queue->rx, queue->rx.req_cons++, &req); 455 meta = npo->meta + npo->meta_prod++; 456 457 if ((1 << gso_type) & vif->gso_mask) { 458 meta->gso_type = gso_type; 459 meta->gso_size = skb_shinfo(skb)->gso_size; 460 } else { 461 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE; 462 meta->gso_size = 0; 463 } 464 465 meta->size = 0; 466 meta->id = req.id; 467 npo->copy_off = 0; 468 npo->copy_gref = req.gref; 469 470 data = skb->data; 471 while (data < skb_tail_pointer(skb)) { 472 unsigned int offset = offset_in_page(data); 473 unsigned int len = PAGE_SIZE - offset; 474 475 if (data + len > skb_tail_pointer(skb)) 476 len = skb_tail_pointer(skb) - data; 477 478 xenvif_gop_frag_copy(queue, skb, npo, 479 virt_to_page(data), len, offset, &head); 480 data += len; 481 } 482 483 for (i = 0; i < nr_frags; i++) { 484 xenvif_gop_frag_copy(queue, skb, npo, 485 skb_frag_page(&skb_shinfo(skb)->frags[i]), 486 skb_frag_size(&skb_shinfo(skb)->frags[i]), 487 skb_shinfo(skb)->frags[i].page_offset, 488 &head); 489 } 490 491 return npo->meta_prod - old_meta_prod; 492 } 493 494 /* 495 * This is a twin to xenvif_gop_skb. Assume that xenvif_gop_skb was 496 * used to set up the operations on the top of 497 * netrx_pending_operations, which have since been done. Check that 498 * they didn't give any errors and advance over them. 499 */ 500 static int xenvif_check_gop(struct xenvif *vif, int nr_meta_slots, 501 struct netrx_pending_operations *npo) 502 { 503 struct gnttab_copy *copy_op; 504 int status = XEN_NETIF_RSP_OKAY; 505 int i; 506 507 for (i = 0; i < nr_meta_slots; i++) { 508 copy_op = npo->copy + npo->copy_cons++; 509 if (copy_op->status != GNTST_okay) { 510 netdev_dbg(vif->dev, 511 "Bad status %d from copy to DOM%d.\n", 512 copy_op->status, vif->domid); 513 status = XEN_NETIF_RSP_ERROR; 514 } 515 } 516 517 return status; 518 } 519 520 static void xenvif_add_frag_responses(struct xenvif_queue *queue, int status, 521 struct xenvif_rx_meta *meta, 522 int nr_meta_slots) 523 { 524 int i; 525 unsigned long offset; 526 527 /* No fragments used */ 528 if (nr_meta_slots <= 1) 529 return; 530 531 nr_meta_slots--; 532 533 for (i = 0; i < nr_meta_slots; i++) { 534 int flags; 535 if (i == nr_meta_slots - 1) 536 flags = 0; 537 else 538 flags = XEN_NETRXF_more_data; 539 540 offset = 0; 541 make_rx_response(queue, meta[i].id, status, offset, 542 meta[i].size, flags); 543 } 544 } 545 546 void xenvif_kick_thread(struct xenvif_queue *queue) 547 { 548 wake_up(&queue->wq); 549 } 550 551 static void xenvif_rx_action(struct xenvif_queue *queue) 552 { 553 s8 status; 554 u16 flags; 555 struct xen_netif_rx_response *resp; 556 struct sk_buff_head rxq; 557 struct sk_buff *skb; 558 LIST_HEAD(notify); 559 int ret; 560 unsigned long offset; 561 bool need_to_notify = false; 562 563 struct netrx_pending_operations npo = { 564 .copy = queue->grant_copy_op, 565 .meta = queue->meta, 566 }; 567 568 skb_queue_head_init(&rxq); 569 570 while (xenvif_rx_ring_slots_available(queue) 571 && (skb = xenvif_rx_dequeue(queue)) != NULL) { 572 queue->last_rx_time = jiffies; 573 574 XENVIF_RX_CB(skb)->meta_slots_used = xenvif_gop_skb(skb, &npo, queue); 575 576 __skb_queue_tail(&rxq, skb); 577 } 578 579 BUG_ON(npo.meta_prod > ARRAY_SIZE(queue->meta)); 580 581 if (!npo.copy_prod) 582 goto done; 583 584 BUG_ON(npo.copy_prod > MAX_GRANT_COPY_OPS); 585 gnttab_batch_copy(queue->grant_copy_op, npo.copy_prod); 586 587 while ((skb = __skb_dequeue(&rxq)) != NULL) { 588 589 if ((1 << queue->meta[npo.meta_cons].gso_type) & 590 queue->vif->gso_prefix_mask) { 591 resp = RING_GET_RESPONSE(&queue->rx, 592 queue->rx.rsp_prod_pvt++); 593 594 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data; 595 596 resp->offset = queue->meta[npo.meta_cons].gso_size; 597 resp->id = queue->meta[npo.meta_cons].id; 598 resp->status = XENVIF_RX_CB(skb)->meta_slots_used; 599 600 npo.meta_cons++; 601 XENVIF_RX_CB(skb)->meta_slots_used--; 602 } 603 604 605 queue->stats.tx_bytes += skb->len; 606 queue->stats.tx_packets++; 607 608 status = xenvif_check_gop(queue->vif, 609 XENVIF_RX_CB(skb)->meta_slots_used, 610 &npo); 611 612 if (XENVIF_RX_CB(skb)->meta_slots_used == 1) 613 flags = 0; 614 else 615 flags = XEN_NETRXF_more_data; 616 617 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */ 618 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated; 619 else if (skb->ip_summed == CHECKSUM_UNNECESSARY) 620 /* remote but checksummed. */ 621 flags |= XEN_NETRXF_data_validated; 622 623 offset = 0; 624 resp = make_rx_response(queue, queue->meta[npo.meta_cons].id, 625 status, offset, 626 queue->meta[npo.meta_cons].size, 627 flags); 628 629 if ((1 << queue->meta[npo.meta_cons].gso_type) & 630 queue->vif->gso_mask) { 631 struct xen_netif_extra_info *gso = 632 (struct xen_netif_extra_info *) 633 RING_GET_RESPONSE(&queue->rx, 634 queue->rx.rsp_prod_pvt++); 635 636 resp->flags |= XEN_NETRXF_extra_info; 637 638 gso->u.gso.type = queue->meta[npo.meta_cons].gso_type; 639 gso->u.gso.size = queue->meta[npo.meta_cons].gso_size; 640 gso->u.gso.pad = 0; 641 gso->u.gso.features = 0; 642 643 gso->type = XEN_NETIF_EXTRA_TYPE_GSO; 644 gso->flags = 0; 645 } 646 647 xenvif_add_frag_responses(queue, status, 648 queue->meta + npo.meta_cons + 1, 649 XENVIF_RX_CB(skb)->meta_slots_used); 650 651 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->rx, ret); 652 653 need_to_notify |= !!ret; 654 655 npo.meta_cons += XENVIF_RX_CB(skb)->meta_slots_used; 656 dev_kfree_skb(skb); 657 } 658 659 done: 660 if (need_to_notify) 661 notify_remote_via_irq(queue->rx_irq); 662 } 663 664 void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue) 665 { 666 int more_to_do; 667 668 RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do); 669 670 if (more_to_do) 671 napi_schedule(&queue->napi); 672 } 673 674 static void tx_add_credit(struct xenvif_queue *queue) 675 { 676 unsigned long max_burst, max_credit; 677 678 /* 679 * Allow a burst big enough to transmit a jumbo packet of up to 128kB. 680 * Otherwise the interface can seize up due to insufficient credit. 681 */ 682 max_burst = max(131072UL, queue->credit_bytes); 683 684 /* Take care that adding a new chunk of credit doesn't wrap to zero. */ 685 max_credit = queue->remaining_credit + queue->credit_bytes; 686 if (max_credit < queue->remaining_credit) 687 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */ 688 689 queue->remaining_credit = min(max_credit, max_burst); 690 } 691 692 void xenvif_tx_credit_callback(unsigned long data) 693 { 694 struct xenvif_queue *queue = (struct xenvif_queue *)data; 695 tx_add_credit(queue); 696 xenvif_napi_schedule_or_enable_events(queue); 697 } 698 699 static void xenvif_tx_err(struct xenvif_queue *queue, 700 struct xen_netif_tx_request *txp, RING_IDX end) 701 { 702 RING_IDX cons = queue->tx.req_cons; 703 unsigned long flags; 704 705 do { 706 spin_lock_irqsave(&queue->response_lock, flags); 707 make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR); 708 push_tx_responses(queue); 709 spin_unlock_irqrestore(&queue->response_lock, flags); 710 if (cons == end) 711 break; 712 RING_COPY_REQUEST(&queue->tx, cons++, txp); 713 } while (1); 714 queue->tx.req_cons = cons; 715 } 716 717 static void xenvif_fatal_tx_err(struct xenvif *vif) 718 { 719 netdev_err(vif->dev, "fatal error; disabling device\n"); 720 vif->disabled = true; 721 /* Disable the vif from queue 0's kthread */ 722 if (vif->queues) 723 xenvif_kick_thread(&vif->queues[0]); 724 } 725 726 static int xenvif_count_requests(struct xenvif_queue *queue, 727 struct xen_netif_tx_request *first, 728 struct xen_netif_tx_request *txp, 729 int work_to_do) 730 { 731 RING_IDX cons = queue->tx.req_cons; 732 int slots = 0; 733 int drop_err = 0; 734 int more_data; 735 736 if (!(first->flags & XEN_NETTXF_more_data)) 737 return 0; 738 739 do { 740 struct xen_netif_tx_request dropped_tx = { 0 }; 741 742 if (slots >= work_to_do) { 743 netdev_err(queue->vif->dev, 744 "Asked for %d slots but exceeds this limit\n", 745 work_to_do); 746 xenvif_fatal_tx_err(queue->vif); 747 return -ENODATA; 748 } 749 750 /* This guest is really using too many slots and 751 * considered malicious. 752 */ 753 if (unlikely(slots >= fatal_skb_slots)) { 754 netdev_err(queue->vif->dev, 755 "Malicious frontend using %d slots, threshold %u\n", 756 slots, fatal_skb_slots); 757 xenvif_fatal_tx_err(queue->vif); 758 return -E2BIG; 759 } 760 761 /* Xen network protocol had implicit dependency on 762 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to 763 * the historical MAX_SKB_FRAGS value 18 to honor the 764 * same behavior as before. Any packet using more than 765 * 18 slots but less than fatal_skb_slots slots is 766 * dropped 767 */ 768 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) { 769 if (net_ratelimit()) 770 netdev_dbg(queue->vif->dev, 771 "Too many slots (%d) exceeding limit (%d), dropping packet\n", 772 slots, XEN_NETBK_LEGACY_SLOTS_MAX); 773 drop_err = -E2BIG; 774 } 775 776 if (drop_err) 777 txp = &dropped_tx; 778 779 RING_COPY_REQUEST(&queue->tx, cons + slots, txp); 780 781 /* If the guest submitted a frame >= 64 KiB then 782 * first->size overflowed and following slots will 783 * appear to be larger than the frame. 784 * 785 * This cannot be fatal error as there are buggy 786 * frontends that do this. 787 * 788 * Consume all slots and drop the packet. 789 */ 790 if (!drop_err && txp->size > first->size) { 791 if (net_ratelimit()) 792 netdev_dbg(queue->vif->dev, 793 "Invalid tx request, slot size %u > remaining size %u\n", 794 txp->size, first->size); 795 drop_err = -EIO; 796 } 797 798 first->size -= txp->size; 799 slots++; 800 801 if (unlikely((txp->offset + txp->size) > XEN_PAGE_SIZE)) { 802 netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %u, size: %u\n", 803 txp->offset, txp->size); 804 xenvif_fatal_tx_err(queue->vif); 805 return -EINVAL; 806 } 807 808 more_data = txp->flags & XEN_NETTXF_more_data; 809 810 if (!drop_err) 811 txp++; 812 813 } while (more_data); 814 815 if (drop_err) { 816 xenvif_tx_err(queue, first, cons + slots); 817 return drop_err; 818 } 819 820 return slots; 821 } 822 823 824 struct xenvif_tx_cb { 825 u16 pending_idx; 826 }; 827 828 #define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb) 829 830 static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue, 831 u16 pending_idx, 832 struct xen_netif_tx_request *txp, 833 struct gnttab_map_grant_ref *mop) 834 { 835 queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx]; 836 gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx), 837 GNTMAP_host_map | GNTMAP_readonly, 838 txp->gref, queue->vif->domid); 839 840 memcpy(&queue->pending_tx_info[pending_idx].req, txp, 841 sizeof(*txp)); 842 } 843 844 static inline struct sk_buff *xenvif_alloc_skb(unsigned int size) 845 { 846 struct sk_buff *skb = 847 alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN, 848 GFP_ATOMIC | __GFP_NOWARN); 849 if (unlikely(skb == NULL)) 850 return NULL; 851 852 /* Packets passed to netif_rx() must have some headroom. */ 853 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN); 854 855 /* Initialize it here to avoid later surprises */ 856 skb_shinfo(skb)->destructor_arg = NULL; 857 858 return skb; 859 } 860 861 static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue, 862 struct sk_buff *skb, 863 struct xen_netif_tx_request *txp, 864 struct gnttab_map_grant_ref *gop, 865 unsigned int frag_overflow, 866 struct sk_buff *nskb) 867 { 868 struct skb_shared_info *shinfo = skb_shinfo(skb); 869 skb_frag_t *frags = shinfo->frags; 870 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx; 871 int start; 872 pending_ring_idx_t index; 873 unsigned int nr_slots; 874 875 nr_slots = shinfo->nr_frags; 876 877 /* Skip first skb fragment if it is on same page as header fragment. */ 878 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx); 879 880 for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots; 881 shinfo->nr_frags++, txp++, gop++) { 882 index = pending_index(queue->pending_cons++); 883 pending_idx = queue->pending_ring[index]; 884 xenvif_tx_create_map_op(queue, pending_idx, txp, gop); 885 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx); 886 } 887 888 if (frag_overflow) { 889 890 shinfo = skb_shinfo(nskb); 891 frags = shinfo->frags; 892 893 for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow; 894 shinfo->nr_frags++, txp++, gop++) { 895 index = pending_index(queue->pending_cons++); 896 pending_idx = queue->pending_ring[index]; 897 xenvif_tx_create_map_op(queue, pending_idx, txp, gop); 898 frag_set_pending_idx(&frags[shinfo->nr_frags], 899 pending_idx); 900 } 901 902 skb_shinfo(skb)->frag_list = nskb; 903 } 904 905 return gop; 906 } 907 908 static inline void xenvif_grant_handle_set(struct xenvif_queue *queue, 909 u16 pending_idx, 910 grant_handle_t handle) 911 { 912 if (unlikely(queue->grant_tx_handle[pending_idx] != 913 NETBACK_INVALID_HANDLE)) { 914 netdev_err(queue->vif->dev, 915 "Trying to overwrite active handle! pending_idx: 0x%x\n", 916 pending_idx); 917 BUG(); 918 } 919 queue->grant_tx_handle[pending_idx] = handle; 920 } 921 922 static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue, 923 u16 pending_idx) 924 { 925 if (unlikely(queue->grant_tx_handle[pending_idx] == 926 NETBACK_INVALID_HANDLE)) { 927 netdev_err(queue->vif->dev, 928 "Trying to unmap invalid handle! pending_idx: 0x%x\n", 929 pending_idx); 930 BUG(); 931 } 932 queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE; 933 } 934 935 static int xenvif_tx_check_gop(struct xenvif_queue *queue, 936 struct sk_buff *skb, 937 struct gnttab_map_grant_ref **gopp_map, 938 struct gnttab_copy **gopp_copy) 939 { 940 struct gnttab_map_grant_ref *gop_map = *gopp_map; 941 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx; 942 /* This always points to the shinfo of the skb being checked, which 943 * could be either the first or the one on the frag_list 944 */ 945 struct skb_shared_info *shinfo = skb_shinfo(skb); 946 /* If this is non-NULL, we are currently checking the frag_list skb, and 947 * this points to the shinfo of the first one 948 */ 949 struct skb_shared_info *first_shinfo = NULL; 950 int nr_frags = shinfo->nr_frags; 951 const bool sharedslot = nr_frags && 952 frag_get_pending_idx(&shinfo->frags[0]) == pending_idx; 953 int i, err; 954 955 /* Check status of header. */ 956 err = (*gopp_copy)->status; 957 if (unlikely(err)) { 958 if (net_ratelimit()) 959 netdev_dbg(queue->vif->dev, 960 "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n", 961 (*gopp_copy)->status, 962 pending_idx, 963 (*gopp_copy)->source.u.ref); 964 /* The first frag might still have this slot mapped */ 965 if (!sharedslot) 966 xenvif_idx_release(queue, pending_idx, 967 XEN_NETIF_RSP_ERROR); 968 } 969 (*gopp_copy)++; 970 971 check_frags: 972 for (i = 0; i < nr_frags; i++, gop_map++) { 973 int j, newerr; 974 975 pending_idx = frag_get_pending_idx(&shinfo->frags[i]); 976 977 /* Check error status: if okay then remember grant handle. */ 978 newerr = gop_map->status; 979 980 if (likely(!newerr)) { 981 xenvif_grant_handle_set(queue, 982 pending_idx, 983 gop_map->handle); 984 /* Had a previous error? Invalidate this fragment. */ 985 if (unlikely(err)) { 986 xenvif_idx_unmap(queue, pending_idx); 987 /* If the mapping of the first frag was OK, but 988 * the header's copy failed, and they are 989 * sharing a slot, send an error 990 */ 991 if (i == 0 && sharedslot) 992 xenvif_idx_release(queue, pending_idx, 993 XEN_NETIF_RSP_ERROR); 994 else 995 xenvif_idx_release(queue, pending_idx, 996 XEN_NETIF_RSP_OKAY); 997 } 998 continue; 999 } 1000 1001 /* Error on this fragment: respond to client with an error. */ 1002 if (net_ratelimit()) 1003 netdev_dbg(queue->vif->dev, 1004 "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n", 1005 i, 1006 gop_map->status, 1007 pending_idx, 1008 gop_map->ref); 1009 1010 xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR); 1011 1012 /* Not the first error? Preceding frags already invalidated. */ 1013 if (err) 1014 continue; 1015 1016 /* First error: if the header haven't shared a slot with the 1017 * first frag, release it as well. 1018 */ 1019 if (!sharedslot) 1020 xenvif_idx_release(queue, 1021 XENVIF_TX_CB(skb)->pending_idx, 1022 XEN_NETIF_RSP_OKAY); 1023 1024 /* Invalidate preceding fragments of this skb. */ 1025 for (j = 0; j < i; j++) { 1026 pending_idx = frag_get_pending_idx(&shinfo->frags[j]); 1027 xenvif_idx_unmap(queue, pending_idx); 1028 xenvif_idx_release(queue, pending_idx, 1029 XEN_NETIF_RSP_OKAY); 1030 } 1031 1032 /* And if we found the error while checking the frag_list, unmap 1033 * the first skb's frags 1034 */ 1035 if (first_shinfo) { 1036 for (j = 0; j < first_shinfo->nr_frags; j++) { 1037 pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]); 1038 xenvif_idx_unmap(queue, pending_idx); 1039 xenvif_idx_release(queue, pending_idx, 1040 XEN_NETIF_RSP_OKAY); 1041 } 1042 } 1043 1044 /* Remember the error: invalidate all subsequent fragments. */ 1045 err = newerr; 1046 } 1047 1048 if (skb_has_frag_list(skb) && !first_shinfo) { 1049 first_shinfo = skb_shinfo(skb); 1050 shinfo = skb_shinfo(skb_shinfo(skb)->frag_list); 1051 nr_frags = shinfo->nr_frags; 1052 1053 goto check_frags; 1054 } 1055 1056 *gopp_map = gop_map; 1057 return err; 1058 } 1059 1060 static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb) 1061 { 1062 struct skb_shared_info *shinfo = skb_shinfo(skb); 1063 int nr_frags = shinfo->nr_frags; 1064 int i; 1065 u16 prev_pending_idx = INVALID_PENDING_IDX; 1066 1067 for (i = 0; i < nr_frags; i++) { 1068 skb_frag_t *frag = shinfo->frags + i; 1069 struct xen_netif_tx_request *txp; 1070 struct page *page; 1071 u16 pending_idx; 1072 1073 pending_idx = frag_get_pending_idx(frag); 1074 1075 /* If this is not the first frag, chain it to the previous*/ 1076 if (prev_pending_idx == INVALID_PENDING_IDX) 1077 skb_shinfo(skb)->destructor_arg = 1078 &callback_param(queue, pending_idx); 1079 else 1080 callback_param(queue, prev_pending_idx).ctx = 1081 &callback_param(queue, pending_idx); 1082 1083 callback_param(queue, pending_idx).ctx = NULL; 1084 prev_pending_idx = pending_idx; 1085 1086 txp = &queue->pending_tx_info[pending_idx].req; 1087 page = virt_to_page(idx_to_kaddr(queue, pending_idx)); 1088 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size); 1089 skb->len += txp->size; 1090 skb->data_len += txp->size; 1091 skb->truesize += txp->size; 1092 1093 /* Take an extra reference to offset network stack's put_page */ 1094 get_page(queue->mmap_pages[pending_idx]); 1095 } 1096 } 1097 1098 static int xenvif_get_extras(struct xenvif_queue *queue, 1099 struct xen_netif_extra_info *extras, 1100 int work_to_do) 1101 { 1102 struct xen_netif_extra_info extra; 1103 RING_IDX cons = queue->tx.req_cons; 1104 1105 do { 1106 if (unlikely(work_to_do-- <= 0)) { 1107 netdev_err(queue->vif->dev, "Missing extra info\n"); 1108 xenvif_fatal_tx_err(queue->vif); 1109 return -EBADR; 1110 } 1111 1112 RING_COPY_REQUEST(&queue->tx, cons, &extra); 1113 if (unlikely(!extra.type || 1114 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) { 1115 queue->tx.req_cons = ++cons; 1116 netdev_err(queue->vif->dev, 1117 "Invalid extra type: %d\n", extra.type); 1118 xenvif_fatal_tx_err(queue->vif); 1119 return -EINVAL; 1120 } 1121 1122 memcpy(&extras[extra.type - 1], &extra, sizeof(extra)); 1123 queue->tx.req_cons = ++cons; 1124 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE); 1125 1126 return work_to_do; 1127 } 1128 1129 static int xenvif_set_skb_gso(struct xenvif *vif, 1130 struct sk_buff *skb, 1131 struct xen_netif_extra_info *gso) 1132 { 1133 if (!gso->u.gso.size) { 1134 netdev_err(vif->dev, "GSO size must not be zero.\n"); 1135 xenvif_fatal_tx_err(vif); 1136 return -EINVAL; 1137 } 1138 1139 switch (gso->u.gso.type) { 1140 case XEN_NETIF_GSO_TYPE_TCPV4: 1141 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1142 break; 1143 case XEN_NETIF_GSO_TYPE_TCPV6: 1144 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1145 break; 1146 default: 1147 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type); 1148 xenvif_fatal_tx_err(vif); 1149 return -EINVAL; 1150 } 1151 1152 skb_shinfo(skb)->gso_size = gso->u.gso.size; 1153 /* gso_segs will be calculated later */ 1154 1155 return 0; 1156 } 1157 1158 static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb) 1159 { 1160 bool recalculate_partial_csum = false; 1161 1162 /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy 1163 * peers can fail to set NETRXF_csum_blank when sending a GSO 1164 * frame. In this case force the SKB to CHECKSUM_PARTIAL and 1165 * recalculate the partial checksum. 1166 */ 1167 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) { 1168 queue->stats.rx_gso_checksum_fixup++; 1169 skb->ip_summed = CHECKSUM_PARTIAL; 1170 recalculate_partial_csum = true; 1171 } 1172 1173 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */ 1174 if (skb->ip_summed != CHECKSUM_PARTIAL) 1175 return 0; 1176 1177 return skb_checksum_setup(skb, recalculate_partial_csum); 1178 } 1179 1180 static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size) 1181 { 1182 u64 now = get_jiffies_64(); 1183 u64 next_credit = queue->credit_window_start + 1184 msecs_to_jiffies(queue->credit_usec / 1000); 1185 1186 /* Timer could already be pending in rare cases. */ 1187 if (timer_pending(&queue->credit_timeout)) 1188 return true; 1189 1190 /* Passed the point where we can replenish credit? */ 1191 if (time_after_eq64(now, next_credit)) { 1192 queue->credit_window_start = now; 1193 tx_add_credit(queue); 1194 } 1195 1196 /* Still too big to send right now? Set a callback. */ 1197 if (size > queue->remaining_credit) { 1198 queue->credit_timeout.data = 1199 (unsigned long)queue; 1200 mod_timer(&queue->credit_timeout, 1201 next_credit); 1202 queue->credit_window_start = next_credit; 1203 1204 return true; 1205 } 1206 1207 return false; 1208 } 1209 1210 /* No locking is required in xenvif_mcast_add/del() as they are 1211 * only ever invoked from NAPI poll. An RCU list is used because 1212 * xenvif_mcast_match() is called asynchronously, during start_xmit. 1213 */ 1214 1215 static int xenvif_mcast_add(struct xenvif *vif, const u8 *addr) 1216 { 1217 struct xenvif_mcast_addr *mcast; 1218 1219 if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) { 1220 if (net_ratelimit()) 1221 netdev_err(vif->dev, 1222 "Too many multicast addresses\n"); 1223 return -ENOSPC; 1224 } 1225 1226 mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC); 1227 if (!mcast) 1228 return -ENOMEM; 1229 1230 ether_addr_copy(mcast->addr, addr); 1231 list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr); 1232 vif->fe_mcast_count++; 1233 1234 return 0; 1235 } 1236 1237 static void xenvif_mcast_del(struct xenvif *vif, const u8 *addr) 1238 { 1239 struct xenvif_mcast_addr *mcast; 1240 1241 list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) { 1242 if (ether_addr_equal(addr, mcast->addr)) { 1243 --vif->fe_mcast_count; 1244 list_del_rcu(&mcast->entry); 1245 kfree_rcu(mcast, rcu); 1246 break; 1247 } 1248 } 1249 } 1250 1251 bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr) 1252 { 1253 struct xenvif_mcast_addr *mcast; 1254 1255 rcu_read_lock(); 1256 list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) { 1257 if (ether_addr_equal(addr, mcast->addr)) { 1258 rcu_read_unlock(); 1259 return true; 1260 } 1261 } 1262 rcu_read_unlock(); 1263 1264 return false; 1265 } 1266 1267 void xenvif_mcast_addr_list_free(struct xenvif *vif) 1268 { 1269 /* No need for locking or RCU here. NAPI poll and TX queue 1270 * are stopped. 1271 */ 1272 while (!list_empty(&vif->fe_mcast_addr)) { 1273 struct xenvif_mcast_addr *mcast; 1274 1275 mcast = list_first_entry(&vif->fe_mcast_addr, 1276 struct xenvif_mcast_addr, 1277 entry); 1278 --vif->fe_mcast_count; 1279 list_del(&mcast->entry); 1280 kfree(mcast); 1281 } 1282 } 1283 1284 static void xenvif_tx_build_gops(struct xenvif_queue *queue, 1285 int budget, 1286 unsigned *copy_ops, 1287 unsigned *map_ops) 1288 { 1289 struct gnttab_map_grant_ref *gop = queue->tx_map_ops; 1290 struct sk_buff *skb, *nskb; 1291 int ret; 1292 unsigned int frag_overflow; 1293 1294 while (skb_queue_len(&queue->tx_queue) < budget) { 1295 struct xen_netif_tx_request txreq; 1296 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX]; 1297 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1]; 1298 u16 pending_idx; 1299 RING_IDX idx; 1300 int work_to_do; 1301 unsigned int data_len; 1302 pending_ring_idx_t index; 1303 1304 if (queue->tx.sring->req_prod - queue->tx.req_cons > 1305 XEN_NETIF_TX_RING_SIZE) { 1306 netdev_err(queue->vif->dev, 1307 "Impossible number of requests. " 1308 "req_prod %d, req_cons %d, size %ld\n", 1309 queue->tx.sring->req_prod, queue->tx.req_cons, 1310 XEN_NETIF_TX_RING_SIZE); 1311 xenvif_fatal_tx_err(queue->vif); 1312 break; 1313 } 1314 1315 work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx); 1316 if (!work_to_do) 1317 break; 1318 1319 idx = queue->tx.req_cons; 1320 rmb(); /* Ensure that we see the request before we copy it. */ 1321 RING_COPY_REQUEST(&queue->tx, idx, &txreq); 1322 1323 /* Credit-based scheduling. */ 1324 if (txreq.size > queue->remaining_credit && 1325 tx_credit_exceeded(queue, txreq.size)) 1326 break; 1327 1328 queue->remaining_credit -= txreq.size; 1329 1330 work_to_do--; 1331 queue->tx.req_cons = ++idx; 1332 1333 memset(extras, 0, sizeof(extras)); 1334 if (txreq.flags & XEN_NETTXF_extra_info) { 1335 work_to_do = xenvif_get_extras(queue, extras, 1336 work_to_do); 1337 idx = queue->tx.req_cons; 1338 if (unlikely(work_to_do < 0)) 1339 break; 1340 } 1341 1342 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) { 1343 struct xen_netif_extra_info *extra; 1344 1345 extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1]; 1346 ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr); 1347 1348 make_tx_response(queue, &txreq, 1349 (ret == 0) ? 1350 XEN_NETIF_RSP_OKAY : 1351 XEN_NETIF_RSP_ERROR); 1352 push_tx_responses(queue); 1353 continue; 1354 } 1355 1356 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) { 1357 struct xen_netif_extra_info *extra; 1358 1359 extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1]; 1360 xenvif_mcast_del(queue->vif, extra->u.mcast.addr); 1361 1362 make_tx_response(queue, &txreq, XEN_NETIF_RSP_OKAY); 1363 push_tx_responses(queue); 1364 continue; 1365 } 1366 1367 ret = xenvif_count_requests(queue, &txreq, txfrags, work_to_do); 1368 if (unlikely(ret < 0)) 1369 break; 1370 1371 idx += ret; 1372 1373 if (unlikely(txreq.size < ETH_HLEN)) { 1374 netdev_dbg(queue->vif->dev, 1375 "Bad packet size: %d\n", txreq.size); 1376 xenvif_tx_err(queue, &txreq, idx); 1377 break; 1378 } 1379 1380 /* No crossing a page as the payload mustn't fragment. */ 1381 if (unlikely((txreq.offset + txreq.size) > XEN_PAGE_SIZE)) { 1382 netdev_err(queue->vif->dev, 1383 "txreq.offset: %u, size: %u, end: %lu\n", 1384 txreq.offset, txreq.size, 1385 (unsigned long)(txreq.offset&~XEN_PAGE_MASK) + txreq.size); 1386 xenvif_fatal_tx_err(queue->vif); 1387 break; 1388 } 1389 1390 index = pending_index(queue->pending_cons); 1391 pending_idx = queue->pending_ring[index]; 1392 1393 data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN && 1394 ret < XEN_NETBK_LEGACY_SLOTS_MAX) ? 1395 XEN_NETBACK_TX_COPY_LEN : txreq.size; 1396 1397 skb = xenvif_alloc_skb(data_len); 1398 if (unlikely(skb == NULL)) { 1399 netdev_dbg(queue->vif->dev, 1400 "Can't allocate a skb in start_xmit.\n"); 1401 xenvif_tx_err(queue, &txreq, idx); 1402 break; 1403 } 1404 1405 skb_shinfo(skb)->nr_frags = ret; 1406 if (data_len < txreq.size) 1407 skb_shinfo(skb)->nr_frags++; 1408 /* At this point shinfo->nr_frags is in fact the number of 1409 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX. 1410 */ 1411 frag_overflow = 0; 1412 nskb = NULL; 1413 if (skb_shinfo(skb)->nr_frags > MAX_SKB_FRAGS) { 1414 frag_overflow = skb_shinfo(skb)->nr_frags - MAX_SKB_FRAGS; 1415 BUG_ON(frag_overflow > MAX_SKB_FRAGS); 1416 skb_shinfo(skb)->nr_frags = MAX_SKB_FRAGS; 1417 nskb = xenvif_alloc_skb(0); 1418 if (unlikely(nskb == NULL)) { 1419 kfree_skb(skb); 1420 xenvif_tx_err(queue, &txreq, idx); 1421 if (net_ratelimit()) 1422 netdev_err(queue->vif->dev, 1423 "Can't allocate the frag_list skb.\n"); 1424 break; 1425 } 1426 } 1427 1428 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) { 1429 struct xen_netif_extra_info *gso; 1430 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1]; 1431 1432 if (xenvif_set_skb_gso(queue->vif, skb, gso)) { 1433 /* Failure in xenvif_set_skb_gso is fatal. */ 1434 kfree_skb(skb); 1435 kfree_skb(nskb); 1436 break; 1437 } 1438 } 1439 1440 XENVIF_TX_CB(skb)->pending_idx = pending_idx; 1441 1442 __skb_put(skb, data_len); 1443 queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref; 1444 queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid; 1445 queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset; 1446 1447 queue->tx_copy_ops[*copy_ops].dest.u.gmfn = 1448 virt_to_gfn(skb->data); 1449 queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF; 1450 queue->tx_copy_ops[*copy_ops].dest.offset = 1451 offset_in_page(skb->data) & ~XEN_PAGE_MASK; 1452 1453 queue->tx_copy_ops[*copy_ops].len = data_len; 1454 queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref; 1455 1456 (*copy_ops)++; 1457 1458 if (data_len < txreq.size) { 1459 frag_set_pending_idx(&skb_shinfo(skb)->frags[0], 1460 pending_idx); 1461 xenvif_tx_create_map_op(queue, pending_idx, &txreq, gop); 1462 gop++; 1463 } else { 1464 frag_set_pending_idx(&skb_shinfo(skb)->frags[0], 1465 INVALID_PENDING_IDX); 1466 memcpy(&queue->pending_tx_info[pending_idx].req, &txreq, 1467 sizeof(txreq)); 1468 } 1469 1470 queue->pending_cons++; 1471 1472 gop = xenvif_get_requests(queue, skb, txfrags, gop, 1473 frag_overflow, nskb); 1474 1475 __skb_queue_tail(&queue->tx_queue, skb); 1476 1477 queue->tx.req_cons = idx; 1478 1479 if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) || 1480 (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops))) 1481 break; 1482 } 1483 1484 (*map_ops) = gop - queue->tx_map_ops; 1485 return; 1486 } 1487 1488 /* Consolidate skb with a frag_list into a brand new one with local pages on 1489 * frags. Returns 0 or -ENOMEM if can't allocate new pages. 1490 */ 1491 static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb) 1492 { 1493 unsigned int offset = skb_headlen(skb); 1494 skb_frag_t frags[MAX_SKB_FRAGS]; 1495 int i, f; 1496 struct ubuf_info *uarg; 1497 struct sk_buff *nskb = skb_shinfo(skb)->frag_list; 1498 1499 queue->stats.tx_zerocopy_sent += 2; 1500 queue->stats.tx_frag_overflow++; 1501 1502 xenvif_fill_frags(queue, nskb); 1503 /* Subtract frags size, we will correct it later */ 1504 skb->truesize -= skb->data_len; 1505 skb->len += nskb->len; 1506 skb->data_len += nskb->len; 1507 1508 /* create a brand new frags array and coalesce there */ 1509 for (i = 0; offset < skb->len; i++) { 1510 struct page *page; 1511 unsigned int len; 1512 1513 BUG_ON(i >= MAX_SKB_FRAGS); 1514 page = alloc_page(GFP_ATOMIC); 1515 if (!page) { 1516 int j; 1517 skb->truesize += skb->data_len; 1518 for (j = 0; j < i; j++) 1519 put_page(frags[j].page.p); 1520 return -ENOMEM; 1521 } 1522 1523 if (offset + PAGE_SIZE < skb->len) 1524 len = PAGE_SIZE; 1525 else 1526 len = skb->len - offset; 1527 if (skb_copy_bits(skb, offset, page_address(page), len)) 1528 BUG(); 1529 1530 offset += len; 1531 frags[i].page.p = page; 1532 frags[i].page_offset = 0; 1533 skb_frag_size_set(&frags[i], len); 1534 } 1535 1536 /* Copied all the bits from the frag list -- free it. */ 1537 skb_frag_list_init(skb); 1538 xenvif_skb_zerocopy_prepare(queue, nskb); 1539 kfree_skb(nskb); 1540 1541 /* Release all the original (foreign) frags. */ 1542 for (f = 0; f < skb_shinfo(skb)->nr_frags; f++) 1543 skb_frag_unref(skb, f); 1544 uarg = skb_shinfo(skb)->destructor_arg; 1545 /* increase inflight counter to offset decrement in callback */ 1546 atomic_inc(&queue->inflight_packets); 1547 uarg->callback(uarg, true); 1548 skb_shinfo(skb)->destructor_arg = NULL; 1549 1550 /* Fill the skb with the new (local) frags. */ 1551 memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t)); 1552 skb_shinfo(skb)->nr_frags = i; 1553 skb->truesize += i * PAGE_SIZE; 1554 1555 return 0; 1556 } 1557 1558 static int xenvif_tx_submit(struct xenvif_queue *queue) 1559 { 1560 struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops; 1561 struct gnttab_copy *gop_copy = queue->tx_copy_ops; 1562 struct sk_buff *skb; 1563 int work_done = 0; 1564 1565 while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) { 1566 struct xen_netif_tx_request *txp; 1567 u16 pending_idx; 1568 unsigned data_len; 1569 1570 pending_idx = XENVIF_TX_CB(skb)->pending_idx; 1571 txp = &queue->pending_tx_info[pending_idx].req; 1572 1573 /* Check the remap error code. */ 1574 if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) { 1575 /* If there was an error, xenvif_tx_check_gop is 1576 * expected to release all the frags which were mapped, 1577 * so kfree_skb shouldn't do it again 1578 */ 1579 skb_shinfo(skb)->nr_frags = 0; 1580 if (skb_has_frag_list(skb)) { 1581 struct sk_buff *nskb = 1582 skb_shinfo(skb)->frag_list; 1583 skb_shinfo(nskb)->nr_frags = 0; 1584 } 1585 kfree_skb(skb); 1586 continue; 1587 } 1588 1589 data_len = skb->len; 1590 callback_param(queue, pending_idx).ctx = NULL; 1591 if (data_len < txp->size) { 1592 /* Append the packet payload as a fragment. */ 1593 txp->offset += data_len; 1594 txp->size -= data_len; 1595 } else { 1596 /* Schedule a response immediately. */ 1597 xenvif_idx_release(queue, pending_idx, 1598 XEN_NETIF_RSP_OKAY); 1599 } 1600 1601 if (txp->flags & XEN_NETTXF_csum_blank) 1602 skb->ip_summed = CHECKSUM_PARTIAL; 1603 else if (txp->flags & XEN_NETTXF_data_validated) 1604 skb->ip_summed = CHECKSUM_UNNECESSARY; 1605 1606 xenvif_fill_frags(queue, skb); 1607 1608 if (unlikely(skb_has_frag_list(skb))) { 1609 if (xenvif_handle_frag_list(queue, skb)) { 1610 if (net_ratelimit()) 1611 netdev_err(queue->vif->dev, 1612 "Not enough memory to consolidate frag_list!\n"); 1613 xenvif_skb_zerocopy_prepare(queue, skb); 1614 kfree_skb(skb); 1615 continue; 1616 } 1617 } 1618 1619 skb->dev = queue->vif->dev; 1620 skb->protocol = eth_type_trans(skb, skb->dev); 1621 skb_reset_network_header(skb); 1622 1623 if (checksum_setup(queue, skb)) { 1624 netdev_dbg(queue->vif->dev, 1625 "Can't setup checksum in net_tx_action\n"); 1626 /* We have to set this flag to trigger the callback */ 1627 if (skb_shinfo(skb)->destructor_arg) 1628 xenvif_skb_zerocopy_prepare(queue, skb); 1629 kfree_skb(skb); 1630 continue; 1631 } 1632 1633 skb_probe_transport_header(skb, 0); 1634 1635 /* If the packet is GSO then we will have just set up the 1636 * transport header offset in checksum_setup so it's now 1637 * straightforward to calculate gso_segs. 1638 */ 1639 if (skb_is_gso(skb)) { 1640 int mss = skb_shinfo(skb)->gso_size; 1641 int hdrlen = skb_transport_header(skb) - 1642 skb_mac_header(skb) + 1643 tcp_hdrlen(skb); 1644 1645 skb_shinfo(skb)->gso_segs = 1646 DIV_ROUND_UP(skb->len - hdrlen, mss); 1647 } 1648 1649 queue->stats.rx_bytes += skb->len; 1650 queue->stats.rx_packets++; 1651 1652 work_done++; 1653 1654 /* Set this flag right before netif_receive_skb, otherwise 1655 * someone might think this packet already left netback, and 1656 * do a skb_copy_ubufs while we are still in control of the 1657 * skb. E.g. the __pskb_pull_tail earlier can do such thing. 1658 */ 1659 if (skb_shinfo(skb)->destructor_arg) { 1660 xenvif_skb_zerocopy_prepare(queue, skb); 1661 queue->stats.tx_zerocopy_sent++; 1662 } 1663 1664 netif_receive_skb(skb); 1665 } 1666 1667 return work_done; 1668 } 1669 1670 void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success) 1671 { 1672 unsigned long flags; 1673 pending_ring_idx_t index; 1674 struct xenvif_queue *queue = ubuf_to_queue(ubuf); 1675 1676 /* This is the only place where we grab this lock, to protect callbacks 1677 * from each other. 1678 */ 1679 spin_lock_irqsave(&queue->callback_lock, flags); 1680 do { 1681 u16 pending_idx = ubuf->desc; 1682 ubuf = (struct ubuf_info *) ubuf->ctx; 1683 BUG_ON(queue->dealloc_prod - queue->dealloc_cons >= 1684 MAX_PENDING_REQS); 1685 index = pending_index(queue->dealloc_prod); 1686 queue->dealloc_ring[index] = pending_idx; 1687 /* Sync with xenvif_tx_dealloc_action: 1688 * insert idx then incr producer. 1689 */ 1690 smp_wmb(); 1691 queue->dealloc_prod++; 1692 } while (ubuf); 1693 spin_unlock_irqrestore(&queue->callback_lock, flags); 1694 1695 if (likely(zerocopy_success)) 1696 queue->stats.tx_zerocopy_success++; 1697 else 1698 queue->stats.tx_zerocopy_fail++; 1699 xenvif_skb_zerocopy_complete(queue); 1700 } 1701 1702 static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue) 1703 { 1704 struct gnttab_unmap_grant_ref *gop; 1705 pending_ring_idx_t dc, dp; 1706 u16 pending_idx, pending_idx_release[MAX_PENDING_REQS]; 1707 unsigned int i = 0; 1708 1709 dc = queue->dealloc_cons; 1710 gop = queue->tx_unmap_ops; 1711 1712 /* Free up any grants we have finished using */ 1713 do { 1714 dp = queue->dealloc_prod; 1715 1716 /* Ensure we see all indices enqueued by all 1717 * xenvif_zerocopy_callback(). 1718 */ 1719 smp_rmb(); 1720 1721 while (dc != dp) { 1722 BUG_ON(gop - queue->tx_unmap_ops >= MAX_PENDING_REQS); 1723 pending_idx = 1724 queue->dealloc_ring[pending_index(dc++)]; 1725 1726 pending_idx_release[gop - queue->tx_unmap_ops] = 1727 pending_idx; 1728 queue->pages_to_unmap[gop - queue->tx_unmap_ops] = 1729 queue->mmap_pages[pending_idx]; 1730 gnttab_set_unmap_op(gop, 1731 idx_to_kaddr(queue, pending_idx), 1732 GNTMAP_host_map, 1733 queue->grant_tx_handle[pending_idx]); 1734 xenvif_grant_handle_reset(queue, pending_idx); 1735 ++gop; 1736 } 1737 1738 } while (dp != queue->dealloc_prod); 1739 1740 queue->dealloc_cons = dc; 1741 1742 if (gop - queue->tx_unmap_ops > 0) { 1743 int ret; 1744 ret = gnttab_unmap_refs(queue->tx_unmap_ops, 1745 NULL, 1746 queue->pages_to_unmap, 1747 gop - queue->tx_unmap_ops); 1748 if (ret) { 1749 netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tu ret %d\n", 1750 gop - queue->tx_unmap_ops, ret); 1751 for (i = 0; i < gop - queue->tx_unmap_ops; ++i) { 1752 if (gop[i].status != GNTST_okay) 1753 netdev_err(queue->vif->dev, 1754 " host_addr: 0x%llx handle: 0x%x status: %d\n", 1755 gop[i].host_addr, 1756 gop[i].handle, 1757 gop[i].status); 1758 } 1759 BUG(); 1760 } 1761 } 1762 1763 for (i = 0; i < gop - queue->tx_unmap_ops; ++i) 1764 xenvif_idx_release(queue, pending_idx_release[i], 1765 XEN_NETIF_RSP_OKAY); 1766 } 1767 1768 1769 /* Called after netfront has transmitted */ 1770 int xenvif_tx_action(struct xenvif_queue *queue, int budget) 1771 { 1772 unsigned nr_mops, nr_cops = 0; 1773 int work_done, ret; 1774 1775 if (unlikely(!tx_work_todo(queue))) 1776 return 0; 1777 1778 xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops); 1779 1780 if (nr_cops == 0) 1781 return 0; 1782 1783 gnttab_batch_copy(queue->tx_copy_ops, nr_cops); 1784 if (nr_mops != 0) { 1785 ret = gnttab_map_refs(queue->tx_map_ops, 1786 NULL, 1787 queue->pages_to_map, 1788 nr_mops); 1789 BUG_ON(ret); 1790 } 1791 1792 work_done = xenvif_tx_submit(queue); 1793 1794 return work_done; 1795 } 1796 1797 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, 1798 u8 status) 1799 { 1800 struct pending_tx_info *pending_tx_info; 1801 pending_ring_idx_t index; 1802 unsigned long flags; 1803 1804 pending_tx_info = &queue->pending_tx_info[pending_idx]; 1805 1806 spin_lock_irqsave(&queue->response_lock, flags); 1807 1808 make_tx_response(queue, &pending_tx_info->req, status); 1809 1810 /* Release the pending index before pusing the Tx response so 1811 * its available before a new Tx request is pushed by the 1812 * frontend. 1813 */ 1814 index = pending_index(queue->pending_prod++); 1815 queue->pending_ring[index] = pending_idx; 1816 1817 push_tx_responses(queue); 1818 1819 spin_unlock_irqrestore(&queue->response_lock, flags); 1820 } 1821 1822 1823 static void make_tx_response(struct xenvif_queue *queue, 1824 struct xen_netif_tx_request *txp, 1825 s8 st) 1826 { 1827 RING_IDX i = queue->tx.rsp_prod_pvt; 1828 struct xen_netif_tx_response *resp; 1829 1830 resp = RING_GET_RESPONSE(&queue->tx, i); 1831 resp->id = txp->id; 1832 resp->status = st; 1833 1834 if (txp->flags & XEN_NETTXF_extra_info) 1835 RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL; 1836 1837 queue->tx.rsp_prod_pvt = ++i; 1838 } 1839 1840 static void push_tx_responses(struct xenvif_queue *queue) 1841 { 1842 int notify; 1843 1844 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify); 1845 if (notify) 1846 notify_remote_via_irq(queue->tx_irq); 1847 } 1848 1849 static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue, 1850 u16 id, 1851 s8 st, 1852 u16 offset, 1853 u16 size, 1854 u16 flags) 1855 { 1856 RING_IDX i = queue->rx.rsp_prod_pvt; 1857 struct xen_netif_rx_response *resp; 1858 1859 resp = RING_GET_RESPONSE(&queue->rx, i); 1860 resp->offset = offset; 1861 resp->flags = flags; 1862 resp->id = id; 1863 resp->status = (s16)size; 1864 if (st < 0) 1865 resp->status = (s16)st; 1866 1867 queue->rx.rsp_prod_pvt = ++i; 1868 1869 return resp; 1870 } 1871 1872 void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx) 1873 { 1874 int ret; 1875 struct gnttab_unmap_grant_ref tx_unmap_op; 1876 1877 gnttab_set_unmap_op(&tx_unmap_op, 1878 idx_to_kaddr(queue, pending_idx), 1879 GNTMAP_host_map, 1880 queue->grant_tx_handle[pending_idx]); 1881 xenvif_grant_handle_reset(queue, pending_idx); 1882 1883 ret = gnttab_unmap_refs(&tx_unmap_op, NULL, 1884 &queue->mmap_pages[pending_idx], 1); 1885 if (ret) { 1886 netdev_err(queue->vif->dev, 1887 "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: 0x%x status: %d\n", 1888 ret, 1889 pending_idx, 1890 tx_unmap_op.host_addr, 1891 tx_unmap_op.handle, 1892 tx_unmap_op.status); 1893 BUG(); 1894 } 1895 } 1896 1897 static inline int tx_work_todo(struct xenvif_queue *queue) 1898 { 1899 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx))) 1900 return 1; 1901 1902 return 0; 1903 } 1904 1905 static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue) 1906 { 1907 return queue->dealloc_cons != queue->dealloc_prod; 1908 } 1909 1910 void xenvif_unmap_frontend_rings(struct xenvif_queue *queue) 1911 { 1912 if (queue->tx.sring) 1913 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif), 1914 queue->tx.sring); 1915 if (queue->rx.sring) 1916 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif), 1917 queue->rx.sring); 1918 } 1919 1920 int xenvif_map_frontend_rings(struct xenvif_queue *queue, 1921 grant_ref_t tx_ring_ref, 1922 grant_ref_t rx_ring_ref) 1923 { 1924 void *addr; 1925 struct xen_netif_tx_sring *txs; 1926 struct xen_netif_rx_sring *rxs; 1927 1928 int err = -ENOMEM; 1929 1930 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif), 1931 &tx_ring_ref, 1, &addr); 1932 if (err) 1933 goto err; 1934 1935 txs = (struct xen_netif_tx_sring *)addr; 1936 BACK_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE); 1937 1938 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif), 1939 &rx_ring_ref, 1, &addr); 1940 if (err) 1941 goto err; 1942 1943 rxs = (struct xen_netif_rx_sring *)addr; 1944 BACK_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE); 1945 1946 return 0; 1947 1948 err: 1949 xenvif_unmap_frontend_rings(queue); 1950 return err; 1951 } 1952 1953 static void xenvif_queue_carrier_off(struct xenvif_queue *queue) 1954 { 1955 struct xenvif *vif = queue->vif; 1956 1957 queue->stalled = true; 1958 1959 /* At least one queue has stalled? Disable the carrier. */ 1960 spin_lock(&vif->lock); 1961 if (vif->stalled_queues++ == 0) { 1962 netdev_info(vif->dev, "Guest Rx stalled"); 1963 netif_carrier_off(vif->dev); 1964 } 1965 spin_unlock(&vif->lock); 1966 } 1967 1968 static void xenvif_queue_carrier_on(struct xenvif_queue *queue) 1969 { 1970 struct xenvif *vif = queue->vif; 1971 1972 queue->last_rx_time = jiffies; /* Reset Rx stall detection. */ 1973 queue->stalled = false; 1974 1975 /* All queues are ready? Enable the carrier. */ 1976 spin_lock(&vif->lock); 1977 if (--vif->stalled_queues == 0) { 1978 netdev_info(vif->dev, "Guest Rx ready"); 1979 netif_carrier_on(vif->dev); 1980 } 1981 spin_unlock(&vif->lock); 1982 } 1983 1984 static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue) 1985 { 1986 RING_IDX prod, cons; 1987 1988 prod = queue->rx.sring->req_prod; 1989 cons = queue->rx.req_cons; 1990 1991 return !queue->stalled && prod - cons < 1 1992 && time_after(jiffies, 1993 queue->last_rx_time + queue->vif->stall_timeout); 1994 } 1995 1996 static bool xenvif_rx_queue_ready(struct xenvif_queue *queue) 1997 { 1998 RING_IDX prod, cons; 1999 2000 prod = queue->rx.sring->req_prod; 2001 cons = queue->rx.req_cons; 2002 2003 return queue->stalled && prod - cons >= 1; 2004 } 2005 2006 static bool xenvif_have_rx_work(struct xenvif_queue *queue) 2007 { 2008 return (!skb_queue_empty(&queue->rx_queue) 2009 && xenvif_rx_ring_slots_available(queue)) 2010 || (queue->vif->stall_timeout && 2011 (xenvif_rx_queue_stalled(queue) 2012 || xenvif_rx_queue_ready(queue))) 2013 || kthread_should_stop() 2014 || queue->vif->disabled; 2015 } 2016 2017 static long xenvif_rx_queue_timeout(struct xenvif_queue *queue) 2018 { 2019 struct sk_buff *skb; 2020 long timeout; 2021 2022 skb = skb_peek(&queue->rx_queue); 2023 if (!skb) 2024 return MAX_SCHEDULE_TIMEOUT; 2025 2026 timeout = XENVIF_RX_CB(skb)->expires - jiffies; 2027 return timeout < 0 ? 0 : timeout; 2028 } 2029 2030 /* Wait until the guest Rx thread has work. 2031 * 2032 * The timeout needs to be adjusted based on the current head of the 2033 * queue (and not just the head at the beginning). In particular, if 2034 * the queue is initially empty an infinite timeout is used and this 2035 * needs to be reduced when a skb is queued. 2036 * 2037 * This cannot be done with wait_event_timeout() because it only 2038 * calculates the timeout once. 2039 */ 2040 static void xenvif_wait_for_rx_work(struct xenvif_queue *queue) 2041 { 2042 DEFINE_WAIT(wait); 2043 2044 if (xenvif_have_rx_work(queue)) 2045 return; 2046 2047 for (;;) { 2048 long ret; 2049 2050 prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE); 2051 if (xenvif_have_rx_work(queue)) 2052 break; 2053 ret = schedule_timeout(xenvif_rx_queue_timeout(queue)); 2054 if (!ret) 2055 break; 2056 } 2057 finish_wait(&queue->wq, &wait); 2058 } 2059 2060 int xenvif_kthread_guest_rx(void *data) 2061 { 2062 struct xenvif_queue *queue = data; 2063 struct xenvif *vif = queue->vif; 2064 2065 if (!vif->stall_timeout) 2066 xenvif_queue_carrier_on(queue); 2067 2068 for (;;) { 2069 xenvif_wait_for_rx_work(queue); 2070 2071 if (kthread_should_stop()) 2072 break; 2073 2074 /* This frontend is found to be rogue, disable it in 2075 * kthread context. Currently this is only set when 2076 * netback finds out frontend sends malformed packet, 2077 * but we cannot disable the interface in softirq 2078 * context so we defer it here, if this thread is 2079 * associated with queue 0. 2080 */ 2081 if (unlikely(vif->disabled && queue->id == 0)) { 2082 xenvif_carrier_off(vif); 2083 break; 2084 } 2085 2086 if (!skb_queue_empty(&queue->rx_queue)) 2087 xenvif_rx_action(queue); 2088 2089 /* If the guest hasn't provided any Rx slots for a 2090 * while it's probably not responsive, drop the 2091 * carrier so packets are dropped earlier. 2092 */ 2093 if (vif->stall_timeout) { 2094 if (xenvif_rx_queue_stalled(queue)) 2095 xenvif_queue_carrier_off(queue); 2096 else if (xenvif_rx_queue_ready(queue)) 2097 xenvif_queue_carrier_on(queue); 2098 } 2099 2100 /* Queued packets may have foreign pages from other 2101 * domains. These cannot be queued indefinitely as 2102 * this would starve guests of grant refs and transmit 2103 * slots. 2104 */ 2105 xenvif_rx_queue_drop_expired(queue); 2106 2107 xenvif_rx_queue_maybe_wake(queue); 2108 2109 cond_resched(); 2110 } 2111 2112 /* Bin any remaining skbs */ 2113 xenvif_rx_queue_purge(queue); 2114 2115 return 0; 2116 } 2117 2118 static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue) 2119 { 2120 /* Dealloc thread must remain running until all inflight 2121 * packets complete. 2122 */ 2123 return kthread_should_stop() && 2124 !atomic_read(&queue->inflight_packets); 2125 } 2126 2127 int xenvif_dealloc_kthread(void *data) 2128 { 2129 struct xenvif_queue *queue = data; 2130 2131 for (;;) { 2132 wait_event_interruptible(queue->dealloc_wq, 2133 tx_dealloc_work_todo(queue) || 2134 xenvif_dealloc_kthread_should_stop(queue)); 2135 if (xenvif_dealloc_kthread_should_stop(queue)) 2136 break; 2137 2138 xenvif_tx_dealloc_action(queue); 2139 cond_resched(); 2140 } 2141 2142 /* Unmap anything remaining*/ 2143 if (tx_dealloc_work_todo(queue)) 2144 xenvif_tx_dealloc_action(queue); 2145 2146 return 0; 2147 } 2148 2149 static int __init netback_init(void) 2150 { 2151 int rc = 0; 2152 2153 if (!xen_domain()) 2154 return -ENODEV; 2155 2156 /* Allow as many queues as there are CPUs if user has not 2157 * specified a value. 2158 */ 2159 if (xenvif_max_queues == 0) 2160 xenvif_max_queues = num_online_cpus(); 2161 2162 if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) { 2163 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n", 2164 fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX); 2165 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX; 2166 } 2167 2168 rc = xenvif_xenbus_init(); 2169 if (rc) 2170 goto failed_init; 2171 2172 #ifdef CONFIG_DEBUG_FS 2173 xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL); 2174 if (IS_ERR_OR_NULL(xen_netback_dbg_root)) 2175 pr_warn("Init of debugfs returned %ld!\n", 2176 PTR_ERR(xen_netback_dbg_root)); 2177 #endif /* CONFIG_DEBUG_FS */ 2178 2179 return 0; 2180 2181 failed_init: 2182 return rc; 2183 } 2184 2185 module_init(netback_init); 2186 2187 static void __exit netback_fini(void) 2188 { 2189 #ifdef CONFIG_DEBUG_FS 2190 if (!IS_ERR_OR_NULL(xen_netback_dbg_root)) 2191 debugfs_remove_recursive(xen_netback_dbg_root); 2192 #endif /* CONFIG_DEBUG_FS */ 2193 xenvif_xenbus_fini(); 2194 } 2195 module_exit(netback_fini); 2196 2197 MODULE_LICENSE("Dual BSD/GPL"); 2198 MODULE_ALIAS("xen-backend:vif"); 2199