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
  48#include <asm/xen/hypercall.h>
  49#include <asm/xen/page.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 */
  55bool separate_tx_rx_irq = 1;
  56module_param(separate_tx_rx_irq, bool, 0644);
  57
  58/* When guest ring is filled up, qdisc queues the packets for us, but we have
  59 * to timeout them, otherwise other guests' packets can get stuck there
  60 */
  61unsigned int rx_drain_timeout_msecs = 10000;
  62module_param(rx_drain_timeout_msecs, uint, 0444);
  63unsigned int rx_drain_timeout_jiffies;
  64
  65/*
  66 * This is the maximum slots a skb can have. If a guest sends a skb
  67 * which exceeds this limit it is considered malicious.
  68 */
  69#define FATAL_SKB_SLOTS_DEFAULT 20
  70static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
  71module_param(fatal_skb_slots, uint, 0444);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  72
  73static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx,
  74			       u8 status);
  75
 
 
 
 
 
 
 
 
 
 
 
 
  76static void make_tx_response(struct xenvif *vif,
  77			     struct xen_netif_tx_request *txp,
  78			     s8       st);
  79
  80static inline int tx_work_todo(struct xenvif *vif);
  81static inline int rx_work_todo(struct xenvif *vif);
  82
  83static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
  84					     u16      id,
  85					     s8       st,
  86					     u16      offset,
  87					     u16      size,
  88					     u16      flags);
  89
  90static inline unsigned long idx_to_pfn(struct xenvif *vif,
  91				       u16 idx)
  92{
  93	return page_to_pfn(vif->mmap_pages[idx]);
  94}
  95
  96static inline unsigned long idx_to_kaddr(struct xenvif *vif,
  97					 u16 idx)
  98{
  99	return (unsigned long)pfn_to_kaddr(idx_to_pfn(vif, idx));
 100}
 101
 102#define callback_param(vif, pending_idx) \
 103	(vif->pending_tx_info[pending_idx].callback_struct)
 
 
 
 
 104
 105/* Find the containing VIF's structure from a pointer in pending_tx_info array
 106 */
 107static inline struct xenvif *ubuf_to_vif(const struct ubuf_info *ubuf)
 
 
 
 108{
 109	u16 pending_idx = ubuf->desc;
 110	struct pending_tx_info *temp =
 111		container_of(ubuf, struct pending_tx_info, callback_struct);
 112	return container_of(temp - pending_idx,
 113			    struct xenvif,
 114			    pending_tx_info[0]);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 115}
 116
 117/* This is a miniumum size for the linear area to avoid lots of
 118 * calls to __pskb_pull_tail() as we set up checksum offsets. The
 119 * value 128 was chosen as it covers all IPv4 and most likely
 120 * IPv6 headers.
 121 */
 122#define PKT_PROT_LEN 128
 
 
 
 123
 124static u16 frag_get_pending_idx(skb_frag_t *frag)
 125{
 126	return (u16)frag->page_offset;
 127}
 128
 129static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
 130{
 131	frag->page_offset = pending_idx;
 
 132}
 133
 134static inline pending_ring_idx_t pending_index(unsigned i)
 135{
 136	return i & (MAX_PENDING_REQS-1);
 137}
 138
 139bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed)
 140{
 141	RING_IDX prod, cons;
 142
 143	do {
 144		prod = vif->rx.sring->req_prod;
 145		cons = vif->rx.req_cons;
 
 
 146
 147		if (prod - cons >= needed)
 148			return true;
 
 
 149
 150		vif->rx.sring->req_event = prod + 1;
 
 
 151
 152		/* Make sure event is visible before we check prod
 153		 * again.
 154		 */
 155		mb();
 156	} while (vif->rx.sring->req_prod != prod);
 157
 158	return false;
 
 
 
 
 159}
 160
 161/*
 162 * Returns true if we should start a new receive buffer instead of
 163 * adding 'size' bytes to a buffer which currently contains 'offset'
 164 * bytes.
 165 */
 166static bool start_new_rx_buffer(int offset, unsigned long size, int head)
 167{
 168	/* simple case: we have completely filled the current buffer. */
 169	if (offset == MAX_BUFFER_OFFSET)
 170		return true;
 171
 172	/*
 173	 * complex case: start a fresh buffer if the current frag
 174	 * would overflow the current buffer but only if:
 175	 *     (i)   this frag would fit completely in the next buffer
 176	 * and (ii)  there is already some data in the current buffer
 177	 * and (iii) this is not the head buffer.
 178	 *
 179	 * Where:
 180	 * - (i) stops us splitting a frag into two copies
 181	 *   unless the frag is too large for a single buffer.
 182	 * - (ii) stops us from leaving a buffer pointlessly empty.
 183	 * - (iii) stops us leaving the first buffer
 184	 *   empty. Strictly speaking this is already covered
 185	 *   by (ii) but is explicitly checked because
 186	 *   netfront relies on the first buffer being
 187	 *   non-empty and can crash otherwise.
 188	 *
 189	 * This means we will effectively linearise small
 190	 * frags but do not needlessly split large buffers
 191	 * into multiple copies tend to give large frags their
 192	 * own buffers as before.
 193	 */
 194	BUG_ON(size > MAX_BUFFER_OFFSET);
 195	if ((offset + size > MAX_BUFFER_OFFSET) && offset && !head)
 196		return true;
 197
 198	return false;
 199}
 200
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 201struct netrx_pending_operations {
 202	unsigned copy_prod, copy_cons;
 203	unsigned meta_prod, meta_cons;
 204	struct gnttab_copy *copy;
 205	struct xenvif_rx_meta *meta;
 206	int copy_off;
 207	grant_ref_t copy_gref;
 208};
 209
 210static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif *vif,
 211						 struct netrx_pending_operations *npo)
 212{
 213	struct xenvif_rx_meta *meta;
 214	struct xen_netif_rx_request *req;
 215
 216	req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
 217
 218	meta = npo->meta + npo->meta_prod++;
 219	meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
 220	meta->gso_size = 0;
 221	meta->size = 0;
 222	meta->id = req->id;
 223
 224	npo->copy_off = 0;
 225	npo->copy_gref = req->gref;
 226
 227	return meta;
 228}
 229
 230/*
 231 * Set up the grant operations for this fragment. If it's a flipping
 232 * interface, we also set up the unmap request from here.
 233 */
 234static void xenvif_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb,
 235				 struct netrx_pending_operations *npo,
 236				 struct page *page, unsigned long size,
 237				 unsigned long offset, int *head,
 238				 struct xenvif *foreign_vif,
 239				 grant_ref_t foreign_gref)
 240{
 241	struct gnttab_copy *copy_gop;
 242	struct xenvif_rx_meta *meta;
 
 
 
 
 
 
 243	unsigned long bytes;
 244	int gso_type = XEN_NETIF_GSO_TYPE_NONE;
 245
 246	/* Data must not cross a page boundary. */
 247	BUG_ON(size + offset > PAGE_SIZE<<compound_order(page));
 248
 249	meta = npo->meta + npo->meta_prod - 1;
 250
 251	/* Skip unused frames from start of page */
 252	page += offset >> PAGE_SHIFT;
 253	offset &= ~PAGE_MASK;
 254
 255	while (size > 0) {
 256		BUG_ON(offset >= PAGE_SIZE);
 257		BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
 258
 259		bytes = PAGE_SIZE - offset;
 260
 261		if (bytes > size)
 262			bytes = size;
 263
 264		if (start_new_rx_buffer(npo->copy_off, bytes, *head)) {
 265			/*
 266			 * Netfront requires there to be some data in the head
 267			 * buffer.
 268			 */
 269			BUG_ON(*head);
 270
 271			meta = get_next_rx_buffer(vif, npo);
 272		}
 273
 
 274		if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
 275			bytes = MAX_BUFFER_OFFSET - npo->copy_off;
 276
 277		copy_gop = npo->copy + npo->copy_prod++;
 278		copy_gop->flags = GNTCOPY_dest_gref;
 279		copy_gop->len = bytes;
 
 
 280
 281		if (foreign_vif) {
 282			copy_gop->source.domid = foreign_vif->domid;
 283			copy_gop->source.u.ref = foreign_gref;
 
 284			copy_gop->flags |= GNTCOPY_source_gref;
 285		} else {
 
 286			copy_gop->source.domid = DOMID_SELF;
 287			copy_gop->source.u.gmfn =
 288				virt_to_mfn(page_address(page));
 289		}
 290		copy_gop->source.offset = offset;
 291
 292		copy_gop->dest.domid = vif->domid;
 
 293		copy_gop->dest.offset = npo->copy_off;
 294		copy_gop->dest.u.ref = npo->copy_gref;
 
 295
 296		npo->copy_off += bytes;
 297		meta->size += bytes;
 298
 299		offset += bytes;
 300		size -= bytes;
 301
 302		/* Next frame */
 303		if (offset == PAGE_SIZE && size) {
 304			BUG_ON(!PageCompound(page));
 305			page++;
 306			offset = 0;
 307		}
 308
 309		/* Leave a gap for the GSO descriptor. */
 310		if (skb_is_gso(skb)) {
 311			if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 312				gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
 313			else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 314				gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
 315		}
 316
 317		if (*head && ((1 << gso_type) & vif->gso_mask))
 318			vif->rx.req_cons++;
 319
 320		*head = 0; /* There must be something in this buffer now. */
 321
 322	}
 323}
 324
 325/*
 326 * Find the grant ref for a given frag in a chain of struct ubuf_info's
 327 * skb: the skb itself
 328 * i: the frag's number
 329 * ubuf: a pointer to an element in the chain. It should not be NULL
 330 *
 331 * Returns a pointer to the element in the chain where the page were found. If
 332 * not found, returns NULL.
 333 * See the definition of callback_struct in common.h for more details about
 334 * the chain.
 335 */
 336static const struct ubuf_info *xenvif_find_gref(const struct sk_buff *const skb,
 337						const int i,
 338						const struct ubuf_info *ubuf)
 339{
 340	struct xenvif *foreign_vif = ubuf_to_vif(ubuf);
 341
 342	do {
 343		u16 pending_idx = ubuf->desc;
 344
 345		if (skb_shinfo(skb)->frags[i].page.p ==
 346		    foreign_vif->mmap_pages[pending_idx])
 347			break;
 348		ubuf = (struct ubuf_info *) ubuf->ctx;
 349	} while (ubuf);
 350
 351	return ubuf;
 352}
 353
 354/*
 355 * Prepare an SKB to be transmitted to the frontend.
 356 *
 357 * This function is responsible for allocating grant operations, meta
 358 * structures, etc.
 359 *
 360 * It returns the number of meta structures consumed. The number of
 361 * ring slots used is always equal to the number of meta slots used
 362 * plus the number of GSO descriptors used. Currently, we use either
 363 * zero GSO descriptors (for non-GSO packets) or one descriptor (for
 364 * frontend-side LRO).
 365 */
 366static int xenvif_gop_skb(struct sk_buff *skb,
 367			  struct netrx_pending_operations *npo)
 368{
 369	struct xenvif *vif = netdev_priv(skb->dev);
 370	int nr_frags = skb_shinfo(skb)->nr_frags;
 371	int i;
 372	struct xen_netif_rx_request *req;
 373	struct xenvif_rx_meta *meta;
 374	unsigned char *data;
 375	int head = 1;
 376	int old_meta_prod;
 377	int gso_type;
 378	const struct ubuf_info *ubuf = skb_shinfo(skb)->destructor_arg;
 379	const struct ubuf_info *const head_ubuf = ubuf;
 380
 381	old_meta_prod = npo->meta_prod;
 382
 383	gso_type = XEN_NETIF_GSO_TYPE_NONE;
 384	if (skb_is_gso(skb)) {
 385		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 386			gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
 387		else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 388			gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
 389	}
 390
 391	/* Set up a GSO prefix descriptor, if necessary */
 392	if ((1 << gso_type) & vif->gso_prefix_mask) {
 393		req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
 394		meta = npo->meta + npo->meta_prod++;
 395		meta->gso_type = gso_type;
 396		meta->gso_size = skb_shinfo(skb)->gso_size;
 397		meta->size = 0;
 398		meta->id = req->id;
 399	}
 400
 401	req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
 402	meta = npo->meta + npo->meta_prod++;
 403
 404	if ((1 << gso_type) & vif->gso_mask) {
 405		meta->gso_type = gso_type;
 406		meta->gso_size = skb_shinfo(skb)->gso_size;
 407	} else {
 408		meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
 409		meta->gso_size = 0;
 410	}
 411
 412	meta->size = 0;
 413	meta->id = req->id;
 414	npo->copy_off = 0;
 415	npo->copy_gref = req->gref;
 416
 417	data = skb->data;
 418	while (data < skb_tail_pointer(skb)) {
 419		unsigned int offset = offset_in_page(data);
 420		unsigned int len = PAGE_SIZE - offset;
 421
 422		if (data + len > skb_tail_pointer(skb))
 423			len = skb_tail_pointer(skb) - data;
 424
 425		xenvif_gop_frag_copy(vif, skb, npo,
 426				     virt_to_page(data), len, offset, &head,
 427				     NULL,
 428				     0);
 429		data += len;
 430	}
 431
 432	for (i = 0; i < nr_frags; i++) {
 433		/* This variable also signals whether foreign_gref has a real
 434		 * value or not.
 435		 */
 436		struct xenvif *foreign_vif = NULL;
 437		grant_ref_t foreign_gref;
 438
 439		if ((skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) &&
 440			(ubuf->callback == &xenvif_zerocopy_callback)) {
 441			const struct ubuf_info *const startpoint = ubuf;
 442
 443			/* Ideally ubuf points to the chain element which
 444			 * belongs to this frag. Or if frags were removed from
 445			 * the beginning, then shortly before it.
 446			 */
 447			ubuf = xenvif_find_gref(skb, i, ubuf);
 448
 449			/* Try again from the beginning of the list, if we
 450			 * haven't tried from there. This only makes sense in
 451			 * the unlikely event of reordering the original frags.
 452			 * For injected local pages it's an unnecessary second
 453			 * run.
 454			 */
 455			if (unlikely(!ubuf) && startpoint != head_ubuf)
 456				ubuf = xenvif_find_gref(skb, i, head_ubuf);
 457
 458			if (likely(ubuf)) {
 459				u16 pending_idx = ubuf->desc;
 460
 461				foreign_vif = ubuf_to_vif(ubuf);
 462				foreign_gref = foreign_vif->pending_tx_info[pending_idx].req.gref;
 463				/* Just a safety measure. If this was the last
 464				 * element on the list, the for loop will
 465				 * iterate again if a local page were added to
 466				 * the end. Using head_ubuf here prevents the
 467				 * second search on the chain. Or the original
 468				 * frags changed order, but that's less likely.
 469				 * In any way, ubuf shouldn't be NULL.
 470				 */
 471				ubuf = ubuf->ctx ?
 472					(struct ubuf_info *) ubuf->ctx :
 473					head_ubuf;
 474			} else
 475				/* This frag was a local page, added to the
 476				 * array after the skb left netback.
 477				 */
 478				ubuf = head_ubuf;
 479		}
 480		xenvif_gop_frag_copy(vif, skb, npo,
 481				     skb_frag_page(&skb_shinfo(skb)->frags[i]),
 482				     skb_frag_size(&skb_shinfo(skb)->frags[i]),
 483				     skb_shinfo(skb)->frags[i].page_offset,
 484				     &head,
 485				     foreign_vif,
 486				     foreign_vif ? foreign_gref : UINT_MAX);
 487	}
 488
 489	return npo->meta_prod - old_meta_prod;
 490}
 491
 492/*
 493 * This is a twin to xenvif_gop_skb.  Assume that xenvif_gop_skb was
 494 * used to set up the operations on the top of
 495 * netrx_pending_operations, which have since been done.  Check that
 496 * they didn't give any errors and advance over them.
 497 */
 498static int xenvif_check_gop(struct xenvif *vif, int nr_meta_slots,
 499			    struct netrx_pending_operations *npo)
 500{
 501	struct gnttab_copy     *copy_op;
 502	int status = XEN_NETIF_RSP_OKAY;
 503	int i;
 504
 505	for (i = 0; i < nr_meta_slots; i++) {
 506		copy_op = npo->copy + npo->copy_cons++;
 507		if (copy_op->status != GNTST_okay) {
 508			netdev_dbg(vif->dev,
 509				   "Bad status %d from copy to DOM%d.\n",
 510				   copy_op->status, vif->domid);
 511			status = XEN_NETIF_RSP_ERROR;
 512		}
 513	}
 514
 515	return status;
 516}
 517
 518static void xenvif_add_frag_responses(struct xenvif *vif, int status,
 519				      struct xenvif_rx_meta *meta,
 520				      int nr_meta_slots)
 521{
 522	int i;
 523	unsigned long offset;
 524
 525	/* No fragments used */
 526	if (nr_meta_slots <= 1)
 527		return;
 528
 529	nr_meta_slots--;
 530
 531	for (i = 0; i < nr_meta_slots; i++) {
 532		int flags;
 533		if (i == nr_meta_slots - 1)
 534			flags = 0;
 535		else
 536			flags = XEN_NETRXF_more_data;
 537
 538		offset = 0;
 539		make_rx_response(vif, meta[i].id, status, offset,
 540				 meta[i].size, flags);
 541	}
 542}
 543
 544struct xenvif_rx_cb {
 545	int meta_slots_used;
 546};
 547
 548#define XENVIF_RX_CB(skb) ((struct xenvif_rx_cb *)(skb)->cb)
 549
 550void xenvif_kick_thread(struct xenvif *vif)
 551{
 552	wake_up(&vif->wq);
 553}
 554
 555static void xenvif_rx_action(struct xenvif *vif)
 556{
 
 557	s8 status;
 558	u16 flags;
 559	struct xen_netif_rx_response *resp;
 560	struct sk_buff_head rxq;
 561	struct sk_buff *skb;
 562	LIST_HEAD(notify);
 563	int ret;
 
 
 564	unsigned long offset;
 565	bool need_to_notify = false;
 566
 567	struct netrx_pending_operations npo = {
 568		.copy  = vif->grant_copy_op,
 569		.meta  = vif->meta,
 570	};
 571
 572	skb_queue_head_init(&rxq);
 573
 574	while ((skb = skb_dequeue(&vif->rx_queue)) != NULL) {
 575		RING_IDX max_slots_needed;
 576		RING_IDX old_req_cons;
 577		RING_IDX ring_slots_used;
 578		int i;
 579
 580		/* We need a cheap worse case estimate for the number of
 581		 * slots we'll use.
 582		 */
 583
 584		max_slots_needed = DIV_ROUND_UP(offset_in_page(skb->data) +
 585						skb_headlen(skb),
 586						PAGE_SIZE);
 587		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 588			unsigned int size;
 589			unsigned int offset;
 590
 591			size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
 592			offset = skb_shinfo(skb)->frags[i].page_offset;
 593
 594			/* For a worse-case estimate we need to factor in
 595			 * the fragment page offset as this will affect the
 596			 * number of times xenvif_gop_frag_copy() will
 597			 * call start_new_rx_buffer().
 598			 */
 599			max_slots_needed += DIV_ROUND_UP(offset + size,
 600							 PAGE_SIZE);
 601		}
 602
 603		/* To avoid the estimate becoming too pessimal for some
 604		 * frontends that limit posted rx requests, cap the estimate
 605		 * at MAX_SKB_FRAGS.
 606		 */
 607		if (max_slots_needed > MAX_SKB_FRAGS)
 608			max_slots_needed = MAX_SKB_FRAGS;
 609
 610		/* We may need one more slot for GSO metadata */
 611		if (skb_is_gso(skb) &&
 612		   (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4 ||
 613		    skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6))
 614			max_slots_needed++;
 615
 616		/* If the skb may not fit then bail out now */
 617		if (!xenvif_rx_ring_slots_available(vif, max_slots_needed)) {
 618			skb_queue_head(&vif->rx_queue, skb);
 619			need_to_notify = true;
 620			vif->rx_last_skb_slots = max_slots_needed;
 621			break;
 622		} else
 623			vif->rx_last_skb_slots = 0;
 624
 625		old_req_cons = vif->rx.req_cons;
 626		XENVIF_RX_CB(skb)->meta_slots_used = xenvif_gop_skb(skb, &npo);
 627		ring_slots_used = vif->rx.req_cons - old_req_cons;
 628
 629		BUG_ON(ring_slots_used > max_slots_needed);
 630
 631		__skb_queue_tail(&rxq, skb);
 
 
 
 
 632	}
 633
 634	BUG_ON(npo.meta_prod > ARRAY_SIZE(vif->meta));
 635
 636	if (!npo.copy_prod)
 637		goto done;
 638
 639	BUG_ON(npo.copy_prod > MAX_GRANT_COPY_OPS);
 640	gnttab_batch_copy(vif->grant_copy_op, npo.copy_prod);
 
 
 641
 642	while ((skb = __skb_dequeue(&rxq)) != NULL) {
 
 
 
 643
 644		if ((1 << vif->meta[npo.meta_cons].gso_type) &
 645		    vif->gso_prefix_mask) {
 646			resp = RING_GET_RESPONSE(&vif->rx,
 647						 vif->rx.rsp_prod_pvt++);
 648
 649			resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
 650
 651			resp->offset = vif->meta[npo.meta_cons].gso_size;
 652			resp->id = vif->meta[npo.meta_cons].id;
 653			resp->status = XENVIF_RX_CB(skb)->meta_slots_used;
 654
 655			npo.meta_cons++;
 656			XENVIF_RX_CB(skb)->meta_slots_used--;
 657		}
 658
 659
 660		vif->dev->stats.tx_bytes += skb->len;
 661		vif->dev->stats.tx_packets++;
 662
 663		status = xenvif_check_gop(vif,
 664					  XENVIF_RX_CB(skb)->meta_slots_used,
 665					  &npo);
 666
 667		if (XENVIF_RX_CB(skb)->meta_slots_used == 1)
 668			flags = 0;
 669		else
 670			flags = XEN_NETRXF_more_data;
 671
 672		if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
 673			flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
 674		else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
 675			/* remote but checksummed. */
 676			flags |= XEN_NETRXF_data_validated;
 677
 678		offset = 0;
 679		resp = make_rx_response(vif, vif->meta[npo.meta_cons].id,
 680					status, offset,
 681					vif->meta[npo.meta_cons].size,
 682					flags);
 683
 684		if ((1 << vif->meta[npo.meta_cons].gso_type) &
 685		    vif->gso_mask) {
 686			struct xen_netif_extra_info *gso =
 687				(struct xen_netif_extra_info *)
 688				RING_GET_RESPONSE(&vif->rx,
 689						  vif->rx.rsp_prod_pvt++);
 690
 691			resp->flags |= XEN_NETRXF_extra_info;
 692
 693			gso->u.gso.type = vif->meta[npo.meta_cons].gso_type;
 694			gso->u.gso.size = vif->meta[npo.meta_cons].gso_size;
 695			gso->u.gso.pad = 0;
 696			gso->u.gso.features = 0;
 697
 698			gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
 699			gso->flags = 0;
 700		}
 701
 702		xenvif_add_frag_responses(vif, status,
 703					  vif->meta + npo.meta_cons + 1,
 704					  XENVIF_RX_CB(skb)->meta_slots_used);
 705
 706		RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret);
 
 
 
 707
 708		need_to_notify |= !!ret;
 709
 710		npo.meta_cons += XENVIF_RX_CB(skb)->meta_slots_used;
 
 711		dev_kfree_skb(skb);
 712	}
 713
 714done:
 715	if (need_to_notify)
 716		notify_remote_via_irq(vif->rx_irq);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 717}
 718
 719void xenvif_napi_schedule_or_enable_events(struct xenvif *vif)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 720{
 721	int more_to_do;
 722
 723	RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
 724
 725	if (more_to_do)
 726		napi_schedule(&vif->napi);
 727}
 728
 729static void tx_add_credit(struct xenvif *vif)
 730{
 731	unsigned long max_burst, max_credit;
 732
 733	/*
 734	 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
 735	 * Otherwise the interface can seize up due to insufficient credit.
 736	 */
 737	max_burst = RING_GET_REQUEST(&vif->tx, vif->tx.req_cons)->size;
 738	max_burst = min(max_burst, 131072UL);
 739	max_burst = max(max_burst, vif->credit_bytes);
 740
 741	/* Take care that adding a new chunk of credit doesn't wrap to zero. */
 742	max_credit = vif->remaining_credit + vif->credit_bytes;
 743	if (max_credit < vif->remaining_credit)
 744		max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
 745
 746	vif->remaining_credit = min(max_credit, max_burst);
 747}
 748
 749static void tx_credit_callback(unsigned long data)
 750{
 751	struct xenvif *vif = (struct xenvif *)data;
 752	tx_add_credit(vif);
 753	xenvif_napi_schedule_or_enable_events(vif);
 754}
 755
 756static void xenvif_tx_err(struct xenvif *vif,
 757			  struct xen_netif_tx_request *txp, RING_IDX end)
 758{
 759	RING_IDX cons = vif->tx.req_cons;
 760	unsigned long flags;
 761
 762	do {
 763		spin_lock_irqsave(&vif->response_lock, flags);
 764		make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
 765		spin_unlock_irqrestore(&vif->response_lock, flags);
 766		if (cons == end)
 767			break;
 768		txp = RING_GET_REQUEST(&vif->tx, cons++);
 769	} while (1);
 770	vif->tx.req_cons = cons;
 
 
 771}
 772
 773static void xenvif_fatal_tx_err(struct xenvif *vif)
 774{
 775	netdev_err(vif->dev, "fatal error; disabling device\n");
 776	vif->disabled = true;
 777	xenvif_kick_thread(vif);
 778}
 779
 780static int xenvif_count_requests(struct xenvif *vif,
 781				 struct xen_netif_tx_request *first,
 782				 struct xen_netif_tx_request *txp,
 783				 int work_to_do)
 784{
 785	RING_IDX cons = vif->tx.req_cons;
 786	int slots = 0;
 787	int drop_err = 0;
 788	int more_data;
 789
 790	if (!(first->flags & XEN_NETTXF_more_data))
 791		return 0;
 792
 793	do {
 794		struct xen_netif_tx_request dropped_tx = { 0 };
 795
 796		if (slots >= work_to_do) {
 797			netdev_err(vif->dev,
 798				   "Asked for %d slots but exceeds this limit\n",
 799				   work_to_do);
 800			xenvif_fatal_tx_err(vif);
 801			return -ENODATA;
 802		}
 803
 804		/* This guest is really using too many slots and
 805		 * considered malicious.
 806		 */
 807		if (unlikely(slots >= fatal_skb_slots)) {
 808			netdev_err(vif->dev,
 809				   "Malicious frontend using %d slots, threshold %u\n",
 810				   slots, fatal_skb_slots);
 811			xenvif_fatal_tx_err(vif);
 812			return -E2BIG;
 813		}
 814
 815		/* Xen network protocol had implicit dependency on
 816		 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
 817		 * the historical MAX_SKB_FRAGS value 18 to honor the
 818		 * same behavior as before. Any packet using more than
 819		 * 18 slots but less than fatal_skb_slots slots is
 820		 * dropped
 821		 */
 822		if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
 823			if (net_ratelimit())
 824				netdev_dbg(vif->dev,
 825					   "Too many slots (%d) exceeding limit (%d), dropping packet\n",
 826					   slots, XEN_NETBK_LEGACY_SLOTS_MAX);
 827			drop_err = -E2BIG;
 828		}
 829
 830		if (drop_err)
 831			txp = &dropped_tx;
 832
 833		memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + slots),
 834		       sizeof(*txp));
 835
 836		/* If the guest submitted a frame >= 64 KiB then
 837		 * first->size overflowed and following slots will
 838		 * appear to be larger than the frame.
 839		 *
 840		 * This cannot be fatal error as there are buggy
 841		 * frontends that do this.
 842		 *
 843		 * Consume all slots and drop the packet.
 844		 */
 845		if (!drop_err && txp->size > first->size) {
 846			if (net_ratelimit())
 847				netdev_dbg(vif->dev,
 848					   "Invalid tx request, slot size %u > remaining size %u\n",
 849					   txp->size, first->size);
 850			drop_err = -EIO;
 851		}
 852
 853		first->size -= txp->size;
 854		slots++;
 855
 856		if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
 857			netdev_err(vif->dev, "Cross page boundary, txp->offset: %x, size: %u\n",
 858				 txp->offset, txp->size);
 859			xenvif_fatal_tx_err(vif);
 860			return -EINVAL;
 861		}
 862
 863		more_data = txp->flags & XEN_NETTXF_more_data;
 864
 865		if (!drop_err)
 866			txp++;
 867
 868	} while (more_data);
 869
 870	if (drop_err) {
 871		xenvif_tx_err(vif, first, cons + slots);
 872		return drop_err;
 873	}
 874
 875	return slots;
 876}
 877
 878
 879struct xenvif_tx_cb {
 880	u16 pending_idx;
 881};
 882
 883#define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
 884
 885static inline void xenvif_tx_create_map_op(struct xenvif *vif,
 886					  u16 pending_idx,
 887					  struct xen_netif_tx_request *txp,
 888					  struct gnttab_map_grant_ref *mop)
 889{
 890	vif->pages_to_map[mop-vif->tx_map_ops] = vif->mmap_pages[pending_idx];
 891	gnttab_set_map_op(mop, idx_to_kaddr(vif, pending_idx),
 892			  GNTMAP_host_map | GNTMAP_readonly,
 893			  txp->gref, vif->domid);
 894
 895	memcpy(&vif->pending_tx_info[pending_idx].req, txp,
 896	       sizeof(*txp));
 897}
 898
 899static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
 
 
 900{
 901	struct sk_buff *skb =
 902		alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
 903			  GFP_ATOMIC | __GFP_NOWARN);
 904	if (unlikely(skb == NULL))
 905		return NULL;
 906
 907	/* Packets passed to netif_rx() must have some headroom. */
 908	skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
 909
 910	/* Initialize it here to avoid later surprises */
 911	skb_shinfo(skb)->destructor_arg = NULL;
 912
 913	return skb;
 914}
 915
 916static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif *vif,
 917							struct sk_buff *skb,
 918							struct xen_netif_tx_request *txp,
 919							struct gnttab_map_grant_ref *gop)
 
 920{
 921	struct skb_shared_info *shinfo = skb_shinfo(skb);
 922	skb_frag_t *frags = shinfo->frags;
 923	u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
 924	int start;
 925	pending_ring_idx_t index;
 926	unsigned int nr_slots, frag_overflow = 0;
 927
 928	/* At this point shinfo->nr_frags is in fact the number of
 929	 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
 930	 */
 931	if (shinfo->nr_frags > MAX_SKB_FRAGS) {
 932		frag_overflow = shinfo->nr_frags - MAX_SKB_FRAGS;
 933		BUG_ON(frag_overflow > MAX_SKB_FRAGS);
 934		shinfo->nr_frags = MAX_SKB_FRAGS;
 935	}
 936	nr_slots = shinfo->nr_frags;
 937
 938	/* Skip first skb fragment if it is on same page as header fragment. */
 939	start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
 940
 941	for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
 942	     shinfo->nr_frags++, txp++, gop++) {
 943		index = pending_index(vif->pending_cons++);
 944		pending_idx = vif->pending_ring[index];
 945		xenvif_tx_create_map_op(vif, pending_idx, txp, gop);
 946		frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
 947	}
 948
 949	if (frag_overflow) {
 950		struct sk_buff *nskb = xenvif_alloc_skb(0);
 951		if (unlikely(nskb == NULL)) {
 952			if (net_ratelimit())
 953				netdev_err(vif->dev,
 954					   "Can't allocate the frag_list skb.\n");
 955			return NULL;
 956		}
 957
 958		shinfo = skb_shinfo(nskb);
 959		frags = shinfo->frags;
 960
 961		for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
 962		     shinfo->nr_frags++, txp++, gop++) {
 963			index = pending_index(vif->pending_cons++);
 964			pending_idx = vif->pending_ring[index];
 965			xenvif_tx_create_map_op(vif, pending_idx, txp, gop);
 966			frag_set_pending_idx(&frags[shinfo->nr_frags],
 967					     pending_idx);
 968		}
 969
 970		skb_shinfo(skb)->frag_list = nskb;
 971	}
 
 972
 973	return gop;
 974}
 975
 976static inline void xenvif_grant_handle_set(struct xenvif *vif,
 977					   u16 pending_idx,
 978					   grant_handle_t handle)
 979{
 980	if (unlikely(vif->grant_tx_handle[pending_idx] !=
 981		     NETBACK_INVALID_HANDLE)) {
 982		netdev_err(vif->dev,
 983			   "Trying to overwrite active handle! pending_idx: %x\n",
 984			   pending_idx);
 985		BUG();
 986	}
 987	vif->grant_tx_handle[pending_idx] = handle;
 988}
 989
 990static inline void xenvif_grant_handle_reset(struct xenvif *vif,
 991					     u16 pending_idx)
 992{
 993	if (unlikely(vif->grant_tx_handle[pending_idx] ==
 994		     NETBACK_INVALID_HANDLE)) {
 995		netdev_err(vif->dev,
 996			   "Trying to unmap invalid handle! pending_idx: %x\n",
 997			   pending_idx);
 998		BUG();
 999	}
1000	vif->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
 
1001}
1002
1003static int xenvif_tx_check_gop(struct xenvif *vif,
1004			       struct sk_buff *skb,
1005			       struct gnttab_map_grant_ref **gopp_map,
1006			       struct gnttab_copy **gopp_copy)
1007{
1008	struct gnttab_map_grant_ref *gop_map = *gopp_map;
1009	u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
 
 
1010	struct skb_shared_info *shinfo = skb_shinfo(skb);
1011	int nr_frags = shinfo->nr_frags;
1012	int i, err;
1013	struct sk_buff *first_skb = NULL;
1014
1015	/* Check status of header. */
1016	err = (*gopp_copy)->status;
1017	(*gopp_copy)++;
1018	if (unlikely(err)) {
1019		if (net_ratelimit())
1020			netdev_dbg(vif->dev,
1021				   "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
1022				   (*gopp_copy)->status,
1023				   pending_idx,
1024				   (*gopp_copy)->source.u.ref);
1025		xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
1026	}
1027
1028check_frags:
1029	for (i = 0; i < nr_frags; i++, gop_map++) {
 
 
1030		int j, newerr;
 
1031
1032		pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
1033
1034		/* Check error status: if okay then remember grant handle. */
1035		newerr = gop_map->status;
1036
1037		if (likely(!newerr)) {
1038			xenvif_grant_handle_set(vif,
1039						pending_idx,
1040						gop_map->handle);
1041			/* Had a previous error? Invalidate this fragment. */
1042			if (unlikely(err))
1043				xenvif_idx_unmap(vif, pending_idx);
1044			continue;
1045		}
1046
1047		/* Error on this fragment: respond to client with an error. */
1048		if (net_ratelimit())
1049			netdev_dbg(vif->dev,
1050				   "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
1051				   i,
1052				   gop_map->status,
1053				   pending_idx,
1054				   gop_map->ref);
1055		xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
1056
1057		/* Not the first error? Preceding frags already invalidated. */
1058		if (err)
1059			continue;
1060		/* First error: invalidate preceding fragments. */
1061		for (j = 0; j < i; j++) {
1062			pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
1063			xenvif_idx_unmap(vif, pending_idx);
 
 
 
1064		}
1065
1066		/* Remember the error: invalidate all subsequent fragments. */
1067		err = newerr;
1068	}
1069
1070	if (skb_has_frag_list(skb)) {
1071		first_skb = skb;
1072		skb = shinfo->frag_list;
1073		shinfo = skb_shinfo(skb);
1074		nr_frags = shinfo->nr_frags;
1075
1076		goto check_frags;
1077	}
1078
1079	/* There was a mapping error in the frag_list skb. We have to unmap
1080	 * the first skb's frags
1081	 */
1082	if (first_skb && err) {
1083		int j;
1084		shinfo = skb_shinfo(first_skb);
1085		for (j = 0; j < shinfo->nr_frags; j++) {
1086			pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
1087			xenvif_idx_unmap(vif, pending_idx);
1088		}
1089	}
1090
1091	*gopp_map = gop_map;
1092	return err;
1093}
1094
1095static void xenvif_fill_frags(struct xenvif *vif, struct sk_buff *skb)
1096{
1097	struct skb_shared_info *shinfo = skb_shinfo(skb);
1098	int nr_frags = shinfo->nr_frags;
1099	int i;
1100	u16 prev_pending_idx = INVALID_PENDING_IDX;
1101
1102	for (i = 0; i < nr_frags; i++) {
1103		skb_frag_t *frag = shinfo->frags + i;
1104		struct xen_netif_tx_request *txp;
1105		struct page *page;
1106		u16 pending_idx;
1107
1108		pending_idx = frag_get_pending_idx(frag);
1109
1110		/* If this is not the first frag, chain it to the previous*/
1111		if (prev_pending_idx == INVALID_PENDING_IDX)
1112			skb_shinfo(skb)->destructor_arg =
1113				&callback_param(vif, pending_idx);
1114		else
1115			callback_param(vif, prev_pending_idx).ctx =
1116				&callback_param(vif, pending_idx);
1117
1118		callback_param(vif, pending_idx).ctx = NULL;
1119		prev_pending_idx = pending_idx;
1120
1121		txp = &vif->pending_tx_info[pending_idx].req;
1122		page = virt_to_page(idx_to_kaddr(vif, pending_idx));
1123		__skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
1124		skb->len += txp->size;
1125		skb->data_len += txp->size;
1126		skb->truesize += txp->size;
1127
1128		/* Take an extra reference to offset network stack's put_page */
1129		get_page(vif->mmap_pages[pending_idx]);
 
1130	}
1131	/* FIXME: __skb_fill_page_desc set this to true because page->pfmemalloc
1132	 * overlaps with "index", and "mapping" is not set. I think mapping
1133	 * should be set. If delivered to local stack, it would drop this
1134	 * skb in sk_filter unless the socket has the right to use it.
1135	 */
1136	skb->pfmemalloc	= false;
1137}
1138
1139static int xenvif_get_extras(struct xenvif *vif,
1140				struct xen_netif_extra_info *extras,
1141				int work_to_do)
1142{
1143	struct xen_netif_extra_info extra;
1144	RING_IDX cons = vif->tx.req_cons;
1145
1146	do {
1147		if (unlikely(work_to_do-- <= 0)) {
1148			netdev_err(vif->dev, "Missing extra info\n");
1149			xenvif_fatal_tx_err(vif);
1150			return -EBADR;
1151		}
1152
1153		memcpy(&extra, RING_GET_REQUEST(&vif->tx, cons),
1154		       sizeof(extra));
1155		if (unlikely(!extra.type ||
1156			     extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1157			vif->tx.req_cons = ++cons;
1158			netdev_err(vif->dev,
1159				   "Invalid extra type: %d\n", extra.type);
1160			xenvif_fatal_tx_err(vif);
1161			return -EINVAL;
1162		}
1163
1164		memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1165		vif->tx.req_cons = ++cons;
1166	} while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1167
1168	return work_to_do;
1169}
1170
1171static int xenvif_set_skb_gso(struct xenvif *vif,
1172			      struct sk_buff *skb,
1173			      struct xen_netif_extra_info *gso)
1174{
1175	if (!gso->u.gso.size) {
1176		netdev_err(vif->dev, "GSO size must not be zero.\n");
1177		xenvif_fatal_tx_err(vif);
1178		return -EINVAL;
1179	}
1180
1181	switch (gso->u.gso.type) {
1182	case XEN_NETIF_GSO_TYPE_TCPV4:
1183		skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1184		break;
1185	case XEN_NETIF_GSO_TYPE_TCPV6:
1186		skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1187		break;
1188	default:
1189		netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1190		xenvif_fatal_tx_err(vif);
1191		return -EINVAL;
1192	}
1193
1194	skb_shinfo(skb)->gso_size = gso->u.gso.size;
1195	/* gso_segs will be calculated later */
 
 
 
 
1196
1197	return 0;
1198}
1199
1200static int checksum_setup(struct xenvif *vif, struct sk_buff *skb)
1201{
1202	bool recalculate_partial_csum = false;
 
 
 
1203
1204	/* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
 
1205	 * peers can fail to set NETRXF_csum_blank when sending a GSO
1206	 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1207	 * recalculate the partial checksum.
1208	 */
1209	if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1210		vif->rx_gso_checksum_fixup++;
1211		skb->ip_summed = CHECKSUM_PARTIAL;
1212		recalculate_partial_csum = true;
1213	}
1214
1215	/* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1216	if (skb->ip_summed != CHECKSUM_PARTIAL)
1217		return 0;
1218
1219	return skb_checksum_setup(skb, recalculate_partial_csum);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1220}
1221
1222static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
1223{
1224	u64 now = get_jiffies_64();
1225	u64 next_credit = vif->credit_window_start +
 
1226		msecs_to_jiffies(vif->credit_usec / 1000);
1227
1228	/* Timer could already be pending in rare cases. */
1229	if (timer_pending(&vif->credit_timeout))
1230		return true;
1231
1232	/* Passed the point where we can replenish credit? */
1233	if (time_after_eq64(now, next_credit)) {
1234		vif->credit_window_start = now;
1235		tx_add_credit(vif);
1236	}
1237
1238	/* Still too big to send right now? Set a callback. */
1239	if (size > vif->remaining_credit) {
1240		vif->credit_timeout.data     =
1241			(unsigned long)vif;
1242		vif->credit_timeout.function =
1243			tx_credit_callback;
1244		mod_timer(&vif->credit_timeout,
1245			  next_credit);
1246		vif->credit_window_start = next_credit;
1247
1248		return true;
1249	}
1250
1251	return false;
1252}
1253
1254static void xenvif_tx_build_gops(struct xenvif *vif,
1255				     int budget,
1256				     unsigned *copy_ops,
1257				     unsigned *map_ops)
1258{
1259	struct gnttab_map_grant_ref *gop = vif->tx_map_ops, *request_gop;
1260	struct sk_buff *skb;
1261	int ret;
1262
1263	while (skb_queue_len(&vif->tx_queue) < budget) {
 
 
1264		struct xen_netif_tx_request txreq;
1265		struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
 
1266		struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
1267		u16 pending_idx;
1268		RING_IDX idx;
1269		int work_to_do;
1270		unsigned int data_len;
1271		pending_ring_idx_t index;
1272
1273		if (vif->tx.sring->req_prod - vif->tx.req_cons >
1274		    XEN_NETIF_TX_RING_SIZE) {
1275			netdev_err(vif->dev,
1276				   "Impossible number of requests. "
1277				   "req_prod %d, req_cons %d, size %ld\n",
1278				   vif->tx.sring->req_prod, vif->tx.req_cons,
1279				   XEN_NETIF_TX_RING_SIZE);
1280			xenvif_fatal_tx_err(vif);
1281			break;
1282		}
1283
1284		work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&vif->tx);
1285		if (!work_to_do)
1286			break;
 
 
1287
1288		idx = vif->tx.req_cons;
1289		rmb(); /* Ensure that we see the request before we copy it. */
1290		memcpy(&txreq, RING_GET_REQUEST(&vif->tx, idx), sizeof(txreq));
1291
1292		/* Credit-based scheduling. */
1293		if (txreq.size > vif->remaining_credit &&
1294		    tx_credit_exceeded(vif, txreq.size))
1295			break;
 
 
1296
1297		vif->remaining_credit -= txreq.size;
1298
1299		work_to_do--;
1300		vif->tx.req_cons = ++idx;
1301
1302		memset(extras, 0, sizeof(extras));
1303		if (txreq.flags & XEN_NETTXF_extra_info) {
1304			work_to_do = xenvif_get_extras(vif, extras,
1305						       work_to_do);
1306			idx = vif->tx.req_cons;
1307			if (unlikely(work_to_do < 0))
1308				break;
 
 
1309		}
1310
1311		ret = xenvif_count_requests(vif, &txreq, txfrags, work_to_do);
1312		if (unlikely(ret < 0))
1313			break;
1314
 
1315		idx += ret;
1316
1317		if (unlikely(txreq.size < ETH_HLEN)) {
1318			netdev_dbg(vif->dev,
1319				   "Bad packet size: %d\n", txreq.size);
1320			xenvif_tx_err(vif, &txreq, idx);
1321			break;
1322		}
1323
1324		/* No crossing a page as the payload mustn't fragment. */
1325		if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
1326			netdev_err(vif->dev,
1327				   "txreq.offset: %x, size: %u, end: %lu\n",
1328				   txreq.offset, txreq.size,
1329				   (txreq.offset&~PAGE_MASK) + txreq.size);
1330			xenvif_fatal_tx_err(vif);
1331			break;
1332		}
1333
1334		index = pending_index(vif->pending_cons);
1335		pending_idx = vif->pending_ring[index];
1336
1337		data_len = (txreq.size > PKT_PROT_LEN &&
1338			    ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
1339			PKT_PROT_LEN : txreq.size;
1340
1341		skb = xenvif_alloc_skb(data_len);
 
1342		if (unlikely(skb == NULL)) {
1343			netdev_dbg(vif->dev,
1344				   "Can't allocate a skb in start_xmit.\n");
1345			xenvif_tx_err(vif, &txreq, idx);
1346			break;
1347		}
1348
 
 
 
1349		if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1350			struct xen_netif_extra_info *gso;
1351			gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1352
1353			if (xenvif_set_skb_gso(vif, skb, gso)) {
1354				/* Failure in xenvif_set_skb_gso is fatal. */
1355				kfree_skb(skb);
1356				break;
 
1357			}
1358		}
1359
1360		XENVIF_TX_CB(skb)->pending_idx = pending_idx;
 
 
 
 
 
 
1361
1362		__skb_put(skb, data_len);
1363		vif->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
1364		vif->tx_copy_ops[*copy_ops].source.domid = vif->domid;
1365		vif->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
1366
1367		vif->tx_copy_ops[*copy_ops].dest.u.gmfn =
1368			virt_to_mfn(skb->data);
1369		vif->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
1370		vif->tx_copy_ops[*copy_ops].dest.offset =
1371			offset_in_page(skb->data);
1372
1373		vif->tx_copy_ops[*copy_ops].len = data_len;
1374		vif->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
 
1375
1376		(*copy_ops)++;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1377
1378		skb_shinfo(skb)->nr_frags = ret;
1379		if (data_len < txreq.size) {
1380			skb_shinfo(skb)->nr_frags++;
1381			frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1382					     pending_idx);
1383			xenvif_tx_create_map_op(vif, pending_idx, &txreq, gop);
1384			gop++;
1385		} else {
1386			frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1387					     INVALID_PENDING_IDX);
1388			memcpy(&vif->pending_tx_info[pending_idx].req, &txreq,
1389			       sizeof(txreq));
1390		}
1391
1392		vif->pending_cons++;
 
 
1393
1394		request_gop = xenvif_get_requests(vif, skb, txfrags, gop);
 
1395		if (request_gop == NULL) {
1396			kfree_skb(skb);
1397			xenvif_tx_err(vif, &txreq, idx);
1398			break;
1399		}
1400		gop = request_gop;
1401
1402		__skb_queue_tail(&vif->tx_queue, skb);
1403
1404		vif->tx.req_cons = idx;
 
1405
1406		if (((gop-vif->tx_map_ops) >= ARRAY_SIZE(vif->tx_map_ops)) ||
1407		    (*copy_ops >= ARRAY_SIZE(vif->tx_copy_ops)))
1408			break;
1409	}
1410
1411	(*map_ops) = gop - vif->tx_map_ops;
1412	return;
1413}
1414
1415/* Consolidate skb with a frag_list into a brand new one with local pages on
1416 * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1417 */
1418static int xenvif_handle_frag_list(struct xenvif *vif, struct sk_buff *skb)
1419{
1420	unsigned int offset = skb_headlen(skb);
1421	skb_frag_t frags[MAX_SKB_FRAGS];
1422	int i;
1423	struct ubuf_info *uarg;
1424	struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1425
1426	vif->tx_zerocopy_sent += 2;
1427	vif->tx_frag_overflow++;
1428
1429	xenvif_fill_frags(vif, nskb);
1430	/* Subtract frags size, we will correct it later */
1431	skb->truesize -= skb->data_len;
1432	skb->len += nskb->len;
1433	skb->data_len += nskb->len;
1434
1435	/* create a brand new frags array and coalesce there */
1436	for (i = 0; offset < skb->len; i++) {
1437		struct page *page;
1438		unsigned int len;
1439
1440		BUG_ON(i >= MAX_SKB_FRAGS);
1441		page = alloc_page(GFP_ATOMIC|__GFP_COLD);
1442		if (!page) {
1443			int j;
1444			skb->truesize += skb->data_len;
1445			for (j = 0; j < i; j++)
1446				put_page(frags[j].page.p);
1447			return -ENOMEM;
1448		}
1449
1450		if (offset + PAGE_SIZE < skb->len)
1451			len = PAGE_SIZE;
1452		else
1453			len = skb->len - offset;
1454		if (skb_copy_bits(skb, offset, page_address(page), len))
1455			BUG();
1456
1457		offset += len;
1458		frags[i].page.p = page;
1459		frags[i].page_offset = 0;
1460		skb_frag_size_set(&frags[i], len);
1461	}
1462	/* swap out with old one */
1463	memcpy(skb_shinfo(skb)->frags,
1464	       frags,
1465	       i * sizeof(skb_frag_t));
1466	skb_shinfo(skb)->nr_frags = i;
1467	skb->truesize += i * PAGE_SIZE;
1468
1469	/* remove traces of mapped pages and frag_list */
1470	skb_frag_list_init(skb);
1471	uarg = skb_shinfo(skb)->destructor_arg;
1472	uarg->callback(uarg, true);
1473	skb_shinfo(skb)->destructor_arg = NULL;
1474
1475	skb_shinfo(nskb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1476	kfree_skb(nskb);
1477
1478	return 0;
1479}
1480
1481static int xenvif_tx_submit(struct xenvif *vif)
1482{
1483	struct gnttab_map_grant_ref *gop_map = vif->tx_map_ops;
1484	struct gnttab_copy *gop_copy = vif->tx_copy_ops;
1485	struct sk_buff *skb;
1486	int work_done = 0;
1487
1488	while ((skb = __skb_dequeue(&vif->tx_queue)) != NULL) {
1489		struct xen_netif_tx_request *txp;
 
1490		u16 pending_idx;
1491		unsigned data_len;
1492
1493		pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1494		txp = &vif->pending_tx_info[pending_idx].req;
 
1495
1496		/* Check the remap error code. */
1497		if (unlikely(xenvif_tx_check_gop(vif, skb, &gop_map, &gop_copy))) {
 
1498			skb_shinfo(skb)->nr_frags = 0;
1499			kfree_skb(skb);
1500			continue;
1501		}
1502
1503		data_len = skb->len;
1504		callback_param(vif, pending_idx).ctx = NULL;
 
 
1505		if (data_len < txp->size) {
1506			/* Append the packet payload as a fragment. */
1507			txp->offset += data_len;
1508			txp->size -= data_len;
1509		} else {
1510			/* Schedule a response immediately. */
1511			xenvif_idx_release(vif, pending_idx,
1512					   XEN_NETIF_RSP_OKAY);
1513		}
1514
1515		if (txp->flags & XEN_NETTXF_csum_blank)
1516			skb->ip_summed = CHECKSUM_PARTIAL;
1517		else if (txp->flags & XEN_NETTXF_data_validated)
1518			skb->ip_summed = CHECKSUM_UNNECESSARY;
1519
1520		xenvif_fill_frags(vif, skb);
1521
1522		if (unlikely(skb_has_frag_list(skb))) {
1523			if (xenvif_handle_frag_list(vif, skb)) {
1524				if (net_ratelimit())
1525					netdev_err(vif->dev,
1526						   "Not enough memory to consolidate frag_list!\n");
1527				skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1528				kfree_skb(skb);
1529				continue;
1530			}
1531		}
1532
1533		if (skb_is_nonlinear(skb) && skb_headlen(skb) < PKT_PROT_LEN) {
1534			int target = min_t(int, skb->len, PKT_PROT_LEN);
1535			__pskb_pull_tail(skb, target - skb_headlen(skb));
1536		}
1537
1538		skb->dev      = vif->dev;
1539		skb->protocol = eth_type_trans(skb, skb->dev);
1540		skb_reset_network_header(skb);
1541
1542		if (checksum_setup(vif, skb)) {
1543			netdev_dbg(vif->dev,
1544				   "Can't setup checksum in net_tx_action\n");
1545			/* We have to set this flag to trigger the callback */
1546			if (skb_shinfo(skb)->destructor_arg)
1547				skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1548			kfree_skb(skb);
1549			continue;
1550		}
1551
1552		skb_probe_transport_header(skb, 0);
1553
1554		/* If the packet is GSO then we will have just set up the
1555		 * transport header offset in checksum_setup so it's now
1556		 * straightforward to calculate gso_segs.
1557		 */
1558		if (skb_is_gso(skb)) {
1559			int mss = skb_shinfo(skb)->gso_size;
1560			int hdrlen = skb_transport_header(skb) -
1561				skb_mac_header(skb) +
1562				tcp_hdrlen(skb);
1563
1564			skb_shinfo(skb)->gso_segs =
1565				DIV_ROUND_UP(skb->len - hdrlen, mss);
1566		}
1567
1568		vif->dev->stats.rx_bytes += skb->len;
1569		vif->dev->stats.rx_packets++;
1570
1571		work_done++;
1572
1573		/* Set this flag right before netif_receive_skb, otherwise
1574		 * someone might think this packet already left netback, and
1575		 * do a skb_copy_ubufs while we are still in control of the
1576		 * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1577		 */
1578		if (skb_shinfo(skb)->destructor_arg) {
1579			skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1580			vif->tx_zerocopy_sent++;
1581		}
1582
1583		netif_receive_skb(skb);
1584	}
1585
1586	return work_done;
1587}
1588
1589void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success)
1590{
1591	unsigned long flags;
1592	pending_ring_idx_t index;
1593	struct xenvif *vif = ubuf_to_vif(ubuf);
1594
1595	/* This is the only place where we grab this lock, to protect callbacks
1596	 * from each other.
1597	 */
1598	spin_lock_irqsave(&vif->callback_lock, flags);
1599	do {
1600		u16 pending_idx = ubuf->desc;
1601		ubuf = (struct ubuf_info *) ubuf->ctx;
1602		BUG_ON(vif->dealloc_prod - vif->dealloc_cons >=
1603			MAX_PENDING_REQS);
1604		index = pending_index(vif->dealloc_prod);
1605		vif->dealloc_ring[index] = pending_idx;
1606		/* Sync with xenvif_tx_dealloc_action:
1607		 * insert idx then incr producer.
1608		 */
1609		smp_wmb();
1610		vif->dealloc_prod++;
1611	} while (ubuf);
1612	wake_up(&vif->dealloc_wq);
1613	spin_unlock_irqrestore(&vif->callback_lock, flags);
1614
1615	if (likely(zerocopy_success))
1616		vif->tx_zerocopy_success++;
1617	else
1618		vif->tx_zerocopy_fail++;
1619}
1620
1621static inline void xenvif_tx_dealloc_action(struct xenvif *vif)
 
1622{
1623	struct gnttab_unmap_grant_ref *gop;
1624	pending_ring_idx_t dc, dp;
1625	u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1626	unsigned int i = 0;
1627
1628	dc = vif->dealloc_cons;
1629	gop = vif->tx_unmap_ops;
1630
1631	/* Free up any grants we have finished using */
1632	do {
1633		dp = vif->dealloc_prod;
1634
1635		/* Ensure we see all indices enqueued by all
1636		 * xenvif_zerocopy_callback().
1637		 */
1638		smp_rmb();
1639
1640		while (dc != dp) {
1641			BUG_ON(gop - vif->tx_unmap_ops > MAX_PENDING_REQS);
1642			pending_idx =
1643				vif->dealloc_ring[pending_index(dc++)];
1644
1645			pending_idx_release[gop-vif->tx_unmap_ops] =
1646				pending_idx;
1647			vif->pages_to_unmap[gop-vif->tx_unmap_ops] =
1648				vif->mmap_pages[pending_idx];
1649			gnttab_set_unmap_op(gop,
1650					    idx_to_kaddr(vif, pending_idx),
1651					    GNTMAP_host_map,
1652					    vif->grant_tx_handle[pending_idx]);
1653			xenvif_grant_handle_reset(vif, pending_idx);
1654			++gop;
1655		}
1656
1657	} while (dp != vif->dealloc_prod);
1658
1659	vif->dealloc_cons = dc;
1660
1661	if (gop - vif->tx_unmap_ops > 0) {
1662		int ret;
1663		ret = gnttab_unmap_refs(vif->tx_unmap_ops,
1664					NULL,
1665					vif->pages_to_unmap,
1666					gop - vif->tx_unmap_ops);
1667		if (ret) {
1668			netdev_err(vif->dev, "Unmap fail: nr_ops %tx ret %d\n",
1669				   gop - vif->tx_unmap_ops, ret);
1670			for (i = 0; i < gop - vif->tx_unmap_ops; ++i) {
1671				if (gop[i].status != GNTST_okay)
1672					netdev_err(vif->dev,
1673						   " host_addr: %llx handle: %x status: %d\n",
1674						   gop[i].host_addr,
1675						   gop[i].handle,
1676						   gop[i].status);
1677			}
1678			BUG();
1679		}
1680	}
1681
1682	for (i = 0; i < gop - vif->tx_unmap_ops; ++i)
1683		xenvif_idx_release(vif, pending_idx_release[i],
1684				   XEN_NETIF_RSP_OKAY);
1685}
1686
1687
1688/* Called after netfront has transmitted */
1689int xenvif_tx_action(struct xenvif *vif, int budget)
1690{
1691	unsigned nr_mops, nr_cops = 0;
1692	int work_done, ret;
1693
1694	if (unlikely(!tx_work_todo(vif)))
1695		return 0;
1696
1697	xenvif_tx_build_gops(vif, budget, &nr_cops, &nr_mops);
 
 
1698
1699	if (nr_cops == 0)
1700		return 0;
1701
1702	gnttab_batch_copy(vif->tx_copy_ops, nr_cops);
1703	if (nr_mops != 0) {
1704		ret = gnttab_map_refs(vif->tx_map_ops,
1705				      NULL,
1706				      vif->pages_to_map,
1707				      nr_mops);
1708		BUG_ON(ret);
1709	}
1710
1711	work_done = xenvif_tx_submit(vif);
1712
1713	return work_done;
1714}
1715
1716static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx,
1717			       u8 status)
1718{
1719	struct pending_tx_info *pending_tx_info;
1720	pending_ring_idx_t index;
1721	unsigned long flags;
1722
1723	pending_tx_info = &vif->pending_tx_info[pending_idx];
1724	spin_lock_irqsave(&vif->response_lock, flags);
1725	make_tx_response(vif, &pending_tx_info->req, status);
1726	index = pending_index(vif->pending_prod);
1727	vif->pending_ring[index] = pending_idx;
1728	/* TX shouldn't use the index before we give it back here */
1729	mb();
1730	vif->pending_prod++;
1731	spin_unlock_irqrestore(&vif->response_lock, flags);
1732}
1733
1734
1735static void make_tx_response(struct xenvif *vif,
1736			     struct xen_netif_tx_request *txp,
1737			     s8       st)
1738{
1739	RING_IDX i = vif->tx.rsp_prod_pvt;
1740	struct xen_netif_tx_response *resp;
1741	int notify;
1742
1743	resp = RING_GET_RESPONSE(&vif->tx, i);
1744	resp->id     = txp->id;
1745	resp->status = st;
1746
1747	if (txp->flags & XEN_NETTXF_extra_info)
1748		RING_GET_RESPONSE(&vif->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1749
1750	vif->tx.rsp_prod_pvt = ++i;
1751	RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->tx, notify);
1752	if (notify)
1753		notify_remote_via_irq(vif->tx_irq);
1754}
1755
1756static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
1757					     u16      id,
1758					     s8       st,
1759					     u16      offset,
1760					     u16      size,
1761					     u16      flags)
1762{
1763	RING_IDX i = vif->rx.rsp_prod_pvt;
1764	struct xen_netif_rx_response *resp;
1765
1766	resp = RING_GET_RESPONSE(&vif->rx, i);
1767	resp->offset     = offset;
1768	resp->flags      = flags;
1769	resp->id         = id;
1770	resp->status     = (s16)size;
1771	if (st < 0)
1772		resp->status = (s16)st;
1773
1774	vif->rx.rsp_prod_pvt = ++i;
1775
1776	return resp;
1777}
1778
1779void xenvif_idx_unmap(struct xenvif *vif, u16 pending_idx)
1780{
1781	int ret;
1782	struct gnttab_unmap_grant_ref tx_unmap_op;
1783
1784	gnttab_set_unmap_op(&tx_unmap_op,
1785			    idx_to_kaddr(vif, pending_idx),
1786			    GNTMAP_host_map,
1787			    vif->grant_tx_handle[pending_idx]);
1788	xenvif_grant_handle_reset(vif, pending_idx);
1789
1790	ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1791				&vif->mmap_pages[pending_idx], 1);
1792	if (ret) {
1793		netdev_err(vif->dev,
1794			   "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: %x status: %d\n",
1795			   ret,
1796			   pending_idx,
1797			   tx_unmap_op.host_addr,
1798			   tx_unmap_op.handle,
1799			   tx_unmap_op.status);
1800		BUG();
1801	}
1802
1803	xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY);
1804}
1805
1806static inline int rx_work_todo(struct xenvif *vif)
1807{
1808	return (!skb_queue_empty(&vif->rx_queue) &&
1809	       xenvif_rx_ring_slots_available(vif, vif->rx_last_skb_slots)) ||
1810	       vif->rx_queue_purge;
1811}
1812
1813static inline int tx_work_todo(struct xenvif *vif)
1814{
1815
1816	if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->tx)))
1817		return 1;
1818
1819	return 0;
1820}
1821
1822static inline bool tx_dealloc_work_todo(struct xenvif *vif)
1823{
1824	return vif->dealloc_cons != vif->dealloc_prod;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1825}
1826
1827void xenvif_unmap_frontend_rings(struct xenvif *vif)
1828{
1829	if (vif->tx.sring)
1830		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1831					vif->tx.sring);
1832	if (vif->rx.sring)
1833		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1834					vif->rx.sring);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1835}
1836
1837int xenvif_map_frontend_rings(struct xenvif *vif,
1838			      grant_ref_t tx_ring_ref,
1839			      grant_ref_t rx_ring_ref)
1840{
1841	void *addr;
1842	struct xen_netif_tx_sring *txs;
1843	struct xen_netif_rx_sring *rxs;
1844
1845	int err = -ENOMEM;
1846
1847	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1848				     tx_ring_ref, &addr);
1849	if (err)
 
 
 
1850		goto err;
1851
1852	txs = (struct xen_netif_tx_sring *)addr;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1853	BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
1854
1855	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1856				     rx_ring_ref, &addr);
1857	if (err)
 
 
 
 
 
 
 
 
1858		goto err;
 
 
 
 
 
1859
1860	rxs = (struct xen_netif_rx_sring *)addr;
1861	BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
1862
1863	return 0;
1864
1865err:
1866	xenvif_unmap_frontend_rings(vif);
1867	return err;
1868}
1869
1870void xenvif_stop_queue(struct xenvif *vif)
1871{
1872	if (!vif->can_queue)
1873		return;
1874
1875	netif_stop_queue(vif->dev);
1876}
1877
1878static void xenvif_start_queue(struct xenvif *vif)
1879{
1880	if (xenvif_schedulable(vif))
1881		netif_wake_queue(vif->dev);
1882}
1883
1884int xenvif_kthread_guest_rx(void *data)
1885{
1886	struct xenvif *vif = data;
1887	struct sk_buff *skb;
1888
1889	while (!kthread_should_stop()) {
1890		wait_event_interruptible(vif->wq,
1891					 rx_work_todo(vif) ||
1892					 vif->disabled ||
1893					 kthread_should_stop());
1894
1895		/* This frontend is found to be rogue, disable it in
1896		 * kthread context. Currently this is only set when
1897		 * netback finds out frontend sends malformed packet,
1898		 * but we cannot disable the interface in softirq
1899		 * context so we defer it here.
1900		 */
1901		if (unlikely(vif->disabled && netif_carrier_ok(vif->dev)))
1902			xenvif_carrier_off(vif);
1903
1904		if (kthread_should_stop())
1905			break;
1906
1907		if (vif->rx_queue_purge) {
1908			skb_queue_purge(&vif->rx_queue);
1909			vif->rx_queue_purge = false;
1910		}
1911
1912		if (!skb_queue_empty(&vif->rx_queue))
1913			xenvif_rx_action(vif);
1914
1915		if (skb_queue_empty(&vif->rx_queue) &&
1916		    netif_queue_stopped(vif->dev)) {
1917			del_timer_sync(&vif->wake_queue);
1918			xenvif_start_queue(vif);
1919		}
1920
1921		cond_resched();
 
 
 
 
1922	}
1923
1924	/* Bin any remaining skbs */
1925	while ((skb = skb_dequeue(&vif->rx_queue)) != NULL)
1926		dev_kfree_skb(skb);
 
1927
1928	return 0;
1929}
 
1930
1931int xenvif_dealloc_kthread(void *data)
1932{
1933	struct xenvif *vif = data;
 
1934
1935	while (!kthread_should_stop()) {
1936		wait_event_interruptible(vif->dealloc_wq,
1937					 tx_dealloc_work_todo(vif) ||
1938					 kthread_should_stop());
1939		if (kthread_should_stop())
1940			break;
1941
1942		xenvif_tx_dealloc_action(vif);
1943		cond_resched();
1944	}
 
 
 
1945
1946	/* Unmap anything remaining*/
1947	if (tx_dealloc_work_todo(vif))
1948		xenvif_tx_dealloc_action(vif);
1949
1950	return 0;
1951}
1952
1953static int __init netback_init(void)
1954{
1955	int rc = 0;
1956
1957	if (!xen_domain())
1958		return -ENODEV;
1959
1960	if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
1961		pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
1962			fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
1963		fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
1964	}
1965
1966	rc = xenvif_xenbus_init();
1967	if (rc)
1968		goto failed_init;
1969
1970	rx_drain_timeout_jiffies = msecs_to_jiffies(rx_drain_timeout_msecs);
1971
1972	return 0;
1973
1974failed_init:
 
 
 
 
 
 
 
 
 
 
1975	return rc;
 
1976}
1977
1978module_init(netback_init);
1979
1980static void __exit netback_fini(void)
1981{
1982	xenvif_xenbus_fini();
1983}
1984module_exit(netback_fini);
1985
1986MODULE_LICENSE("Dual BSD/GPL");
1987MODULE_ALIAS("xen-backend:vif");