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 */
  55bool separate_tx_rx_irq = true;
  56module_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 */
  61unsigned int rx_drain_timeout_msecs = 10000;
  62module_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 */
  67unsigned int rx_stall_timeout_msecs = 60000;
  68module_param(rx_stall_timeout_msecs, uint, 0444);
  69
  70#define MAX_QUEUES_DEFAULT 8
  71unsigned int xenvif_max_queues;
  72module_param_named(max_queues, xenvif_max_queues, uint, 0644);
  73MODULE_PARM_DESC(max_queues,
  74		 "Maximum number of queues per virtual interface");
  75
  76/*
  77 * This is the maximum slots a skb can have. If a guest sends a skb
  78 * which exceeds this limit it is considered malicious.
  79 */
  80#define FATAL_SKB_SLOTS_DEFAULT 20
  81static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
  82module_param(fatal_skb_slots, uint, 0444);
  83
  84/* The amount to copy out of the first guest Tx slot into the skb's
  85 * linear area.  If the first slot has more data, it will be mapped
  86 * and put into the first frag.
  87 *
  88 * This is sized to avoid pulling headers from the frags for most
  89 * TCP/IP packets.
  90 */
  91#define XEN_NETBACK_TX_COPY_LEN 128
  92
  93/* This is the maximum number of flows in the hash cache. */
  94#define XENVIF_HASH_CACHE_SIZE_DEFAULT 64
  95unsigned int xenvif_hash_cache_size = XENVIF_HASH_CACHE_SIZE_DEFAULT;
  96module_param_named(hash_cache_size, xenvif_hash_cache_size, uint, 0644);
  97MODULE_PARM_DESC(hash_cache_size, "Number of flows in the hash cache");
  98
  99/* The module parameter tells that we have to put data
 100 * for xen-netfront with the XDP_PACKET_HEADROOM offset
 101 * needed for XDP processing
 102 */
 103bool provides_xdp_headroom = true;
 104module_param(provides_xdp_headroom, bool, 0644);
 105
 106static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
 107			       u8 status);
 108
 109static void make_tx_response(struct xenvif_queue *queue,
 110			     struct xen_netif_tx_request *txp,
 111			     unsigned int extra_count,
 112			     s8       st);
 113static void push_tx_responses(struct xenvif_queue *queue);
 114
 115static inline int tx_work_todo(struct xenvif_queue *queue);
 116
 117static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
 118				       u16 idx)
 119{
 120	return page_to_pfn(queue->mmap_pages[idx]);
 121}
 122
 123static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
 124					 u16 idx)
 125{
 126	return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
 127}
 128
 129#define callback_param(vif, pending_idx) \
 130	(vif->pending_tx_info[pending_idx].callback_struct)
 131
 132/* Find the containing VIF's structure from a pointer in pending_tx_info array
 133 */
 134static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf)
 135{
 136	u16 pending_idx = ubuf->desc;
 137	struct pending_tx_info *temp =
 138		container_of(ubuf, struct pending_tx_info, callback_struct);
 139	return container_of(temp - pending_idx,
 140			    struct xenvif_queue,
 141			    pending_tx_info[0]);
 142}
 143
 144static u16 frag_get_pending_idx(skb_frag_t *frag)
 145{
 146	return (u16)skb_frag_off(frag);
 147}
 148
 149static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
 150{
 151	skb_frag_off_set(frag, pending_idx);
 152}
 153
 154static inline pending_ring_idx_t pending_index(unsigned i)
 155{
 156	return i & (MAX_PENDING_REQS-1);
 157}
 158
 159void xenvif_kick_thread(struct xenvif_queue *queue)
 160{
 161	wake_up(&queue->wq);
 162}
 163
 164void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
 165{
 166	int more_to_do;
 167
 168	RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
 169
 170	if (more_to_do)
 171		napi_schedule(&queue->napi);
 172	else if (atomic_fetch_andnot(NETBK_TX_EOI | NETBK_COMMON_EOI,
 173				     &queue->eoi_pending) &
 174		 (NETBK_TX_EOI | NETBK_COMMON_EOI))
 175		xen_irq_lateeoi(queue->tx_irq, 0);
 176}
 177
 178static void tx_add_credit(struct xenvif_queue *queue)
 179{
 180	unsigned long max_burst, max_credit;
 181
 182	/*
 183	 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
 184	 * Otherwise the interface can seize up due to insufficient credit.
 185	 */
 186	max_burst = max(131072UL, queue->credit_bytes);
 187
 188	/* Take care that adding a new chunk of credit doesn't wrap to zero. */
 189	max_credit = queue->remaining_credit + queue->credit_bytes;
 190	if (max_credit < queue->remaining_credit)
 191		max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
 192
 193	queue->remaining_credit = min(max_credit, max_burst);
 194	queue->rate_limited = false;
 195}
 196
 197void xenvif_tx_credit_callback(struct timer_list *t)
 198{
 199	struct xenvif_queue *queue = from_timer(queue, t, credit_timeout);
 200	tx_add_credit(queue);
 201	xenvif_napi_schedule_or_enable_events(queue);
 202}
 203
 204static void xenvif_tx_err(struct xenvif_queue *queue,
 205			  struct xen_netif_tx_request *txp,
 206			  unsigned int extra_count, RING_IDX end)
 207{
 208	RING_IDX cons = queue->tx.req_cons;
 209	unsigned long flags;
 210
 211	do {
 212		spin_lock_irqsave(&queue->response_lock, flags);
 213		make_tx_response(queue, txp, extra_count, XEN_NETIF_RSP_ERROR);
 214		push_tx_responses(queue);
 215		spin_unlock_irqrestore(&queue->response_lock, flags);
 216		if (cons == end)
 217			break;
 218		RING_COPY_REQUEST(&queue->tx, cons++, txp);
 219		extra_count = 0; /* only the first frag can have extras */
 220	} while (1);
 221	queue->tx.req_cons = cons;
 222}
 223
 224static void xenvif_fatal_tx_err(struct xenvif *vif)
 225{
 226	netdev_err(vif->dev, "fatal error; disabling device\n");
 227	vif->disabled = true;
 228	/* Disable the vif from queue 0's kthread */
 229	if (vif->num_queues)
 230		xenvif_kick_thread(&vif->queues[0]);
 231}
 232
 233static int xenvif_count_requests(struct xenvif_queue *queue,
 234				 struct xen_netif_tx_request *first,
 235				 unsigned int extra_count,
 236				 struct xen_netif_tx_request *txp,
 237				 int work_to_do)
 238{
 239	RING_IDX cons = queue->tx.req_cons;
 240	int slots = 0;
 241	int drop_err = 0;
 242	int more_data;
 243
 244	if (!(first->flags & XEN_NETTXF_more_data))
 245		return 0;
 246
 247	do {
 248		struct xen_netif_tx_request dropped_tx = { 0 };
 249
 250		if (slots >= work_to_do) {
 251			netdev_err(queue->vif->dev,
 252				   "Asked for %d slots but exceeds this limit\n",
 253				   work_to_do);
 254			xenvif_fatal_tx_err(queue->vif);
 255			return -ENODATA;
 256		}
 257
 258		/* This guest is really using too many slots and
 259		 * considered malicious.
 260		 */
 261		if (unlikely(slots >= fatal_skb_slots)) {
 262			netdev_err(queue->vif->dev,
 263				   "Malicious frontend using %d slots, threshold %u\n",
 264				   slots, fatal_skb_slots);
 265			xenvif_fatal_tx_err(queue->vif);
 266			return -E2BIG;
 267		}
 268
 269		/* Xen network protocol had implicit dependency on
 270		 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
 271		 * the historical MAX_SKB_FRAGS value 18 to honor the
 272		 * same behavior as before. Any packet using more than
 273		 * 18 slots but less than fatal_skb_slots slots is
 274		 * dropped
 275		 */
 276		if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
 277			if (net_ratelimit())
 278				netdev_dbg(queue->vif->dev,
 279					   "Too many slots (%d) exceeding limit (%d), dropping packet\n",
 280					   slots, XEN_NETBK_LEGACY_SLOTS_MAX);
 281			drop_err = -E2BIG;
 282		}
 283
 284		if (drop_err)
 285			txp = &dropped_tx;
 286
 287		RING_COPY_REQUEST(&queue->tx, cons + slots, txp);
 288
 289		/* If the guest submitted a frame >= 64 KiB then
 290		 * first->size overflowed and following slots will
 291		 * appear to be larger than the frame.
 292		 *
 293		 * This cannot be fatal error as there are buggy
 294		 * frontends that do this.
 295		 *
 296		 * Consume all slots and drop the packet.
 297		 */
 298		if (!drop_err && txp->size > first->size) {
 299			if (net_ratelimit())
 300				netdev_dbg(queue->vif->dev,
 301					   "Invalid tx request, slot size %u > remaining size %u\n",
 302					   txp->size, first->size);
 303			drop_err = -EIO;
 304		}
 305
 306		first->size -= txp->size;
 307		slots++;
 308
 309		if (unlikely((txp->offset + txp->size) > XEN_PAGE_SIZE)) {
 310			netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %u, size: %u\n",
 311				 txp->offset, txp->size);
 312			xenvif_fatal_tx_err(queue->vif);
 313			return -EINVAL;
 314		}
 315
 316		more_data = txp->flags & XEN_NETTXF_more_data;
 317
 318		if (!drop_err)
 319			txp++;
 320
 321	} while (more_data);
 322
 323	if (drop_err) {
 324		xenvif_tx_err(queue, first, extra_count, cons + slots);
 325		return drop_err;
 326	}
 327
 328	return slots;
 329}
 330
 331
 332struct xenvif_tx_cb {
 333	u16 pending_idx;
 334};
 335
 336#define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
 337
 338static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
 339					   u16 pending_idx,
 340					   struct xen_netif_tx_request *txp,
 341					   unsigned int extra_count,
 342					   struct gnttab_map_grant_ref *mop)
 343{
 344	queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
 345	gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
 346			  GNTMAP_host_map | GNTMAP_readonly,
 347			  txp->gref, queue->vif->domid);
 348
 349	memcpy(&queue->pending_tx_info[pending_idx].req, txp,
 350	       sizeof(*txp));
 351	queue->pending_tx_info[pending_idx].extra_count = extra_count;
 352}
 353
 354static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
 355{
 356	struct sk_buff *skb =
 357		alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
 358			  GFP_ATOMIC | __GFP_NOWARN);
 359	if (unlikely(skb == NULL))
 360		return NULL;
 361
 362	/* Packets passed to netif_rx() must have some headroom. */
 363	skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
 364
 365	/* Initialize it here to avoid later surprises */
 366	skb_shinfo(skb)->destructor_arg = NULL;
 367
 368	return skb;
 369}
 370
 371static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue,
 372							struct sk_buff *skb,
 373							struct xen_netif_tx_request *txp,
 374							struct gnttab_map_grant_ref *gop,
 375							unsigned int frag_overflow,
 376							struct sk_buff *nskb)
 377{
 378	struct skb_shared_info *shinfo = skb_shinfo(skb);
 379	skb_frag_t *frags = shinfo->frags;
 380	u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
 381	int start;
 382	pending_ring_idx_t index;
 383	unsigned int nr_slots;
 384
 385	nr_slots = shinfo->nr_frags;
 386
 387	/* Skip first skb fragment if it is on same page as header fragment. */
 388	start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
 389
 390	for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
 391	     shinfo->nr_frags++, txp++, gop++) {
 392		index = pending_index(queue->pending_cons++);
 393		pending_idx = queue->pending_ring[index];
 394		xenvif_tx_create_map_op(queue, pending_idx, txp, 0, gop);
 395		frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
 396	}
 397
 398	if (frag_overflow) {
 399
 400		shinfo = skb_shinfo(nskb);
 401		frags = shinfo->frags;
 402
 403		for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
 404		     shinfo->nr_frags++, txp++, gop++) {
 405			index = pending_index(queue->pending_cons++);
 406			pending_idx = queue->pending_ring[index];
 407			xenvif_tx_create_map_op(queue, pending_idx, txp, 0,
 408						gop);
 409			frag_set_pending_idx(&frags[shinfo->nr_frags],
 410					     pending_idx);
 411		}
 412
 413		skb_shinfo(skb)->frag_list = nskb;
 414	}
 415
 416	return gop;
 417}
 418
 419static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
 420					   u16 pending_idx,
 421					   grant_handle_t handle)
 422{
 423	if (unlikely(queue->grant_tx_handle[pending_idx] !=
 424		     NETBACK_INVALID_HANDLE)) {
 425		netdev_err(queue->vif->dev,
 426			   "Trying to overwrite active handle! pending_idx: 0x%x\n",
 427			   pending_idx);
 428		BUG();
 429	}
 430	queue->grant_tx_handle[pending_idx] = handle;
 431}
 432
 433static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
 434					     u16 pending_idx)
 435{
 436	if (unlikely(queue->grant_tx_handle[pending_idx] ==
 437		     NETBACK_INVALID_HANDLE)) {
 438		netdev_err(queue->vif->dev,
 439			   "Trying to unmap invalid handle! pending_idx: 0x%x\n",
 440			   pending_idx);
 441		BUG();
 442	}
 443	queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
 444}
 445
 446static int xenvif_tx_check_gop(struct xenvif_queue *queue,
 447			       struct sk_buff *skb,
 448			       struct gnttab_map_grant_ref **gopp_map,
 449			       struct gnttab_copy **gopp_copy)
 450{
 451	struct gnttab_map_grant_ref *gop_map = *gopp_map;
 452	u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
 453	/* This always points to the shinfo of the skb being checked, which
 454	 * could be either the first or the one on the frag_list
 455	 */
 456	struct skb_shared_info *shinfo = skb_shinfo(skb);
 457	/* If this is non-NULL, we are currently checking the frag_list skb, and
 458	 * this points to the shinfo of the first one
 459	 */
 460	struct skb_shared_info *first_shinfo = NULL;
 461	int nr_frags = shinfo->nr_frags;
 462	const bool sharedslot = nr_frags &&
 463				frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
 464	int i, err;
 465
 466	/* Check status of header. */
 467	err = (*gopp_copy)->status;
 468	if (unlikely(err)) {
 469		if (net_ratelimit())
 470			netdev_dbg(queue->vif->dev,
 471				   "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
 472				   (*gopp_copy)->status,
 473				   pending_idx,
 474				   (*gopp_copy)->source.u.ref);
 475		/* The first frag might still have this slot mapped */
 476		if (!sharedslot)
 477			xenvif_idx_release(queue, pending_idx,
 478					   XEN_NETIF_RSP_ERROR);
 479	}
 480	(*gopp_copy)++;
 481
 482check_frags:
 483	for (i = 0; i < nr_frags; i++, gop_map++) {
 484		int j, newerr;
 485
 486		pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
 487
 488		/* Check error status: if okay then remember grant handle. */
 489		newerr = gop_map->status;
 490
 491		if (likely(!newerr)) {
 492			xenvif_grant_handle_set(queue,
 493						pending_idx,
 494						gop_map->handle);
 495			/* Had a previous error? Invalidate this fragment. */
 496			if (unlikely(err)) {
 497				xenvif_idx_unmap(queue, pending_idx);
 498				/* If the mapping of the first frag was OK, but
 499				 * the header's copy failed, and they are
 500				 * sharing a slot, send an error
 501				 */
 502				if (i == 0 && !first_shinfo && sharedslot)
 503					xenvif_idx_release(queue, pending_idx,
 504							   XEN_NETIF_RSP_ERROR);
 505				else
 506					xenvif_idx_release(queue, pending_idx,
 507							   XEN_NETIF_RSP_OKAY);
 508			}
 509			continue;
 510		}
 511
 512		/* Error on this fragment: respond to client with an error. */
 513		if (net_ratelimit())
 514			netdev_dbg(queue->vif->dev,
 515				   "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
 516				   i,
 517				   gop_map->status,
 518				   pending_idx,
 519				   gop_map->ref);
 520
 521		xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
 522
 523		/* Not the first error? Preceding frags already invalidated. */
 524		if (err)
 525			continue;
 526
 527		/* First error: if the header haven't shared a slot with the
 528		 * first frag, release it as well.
 529		 */
 530		if (!sharedslot)
 531			xenvif_idx_release(queue,
 532					   XENVIF_TX_CB(skb)->pending_idx,
 533					   XEN_NETIF_RSP_OKAY);
 534
 535		/* Invalidate preceding fragments of this skb. */
 536		for (j = 0; j < i; j++) {
 537			pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
 538			xenvif_idx_unmap(queue, pending_idx);
 539			xenvif_idx_release(queue, pending_idx,
 540					   XEN_NETIF_RSP_OKAY);
 541		}
 542
 543		/* And if we found the error while checking the frag_list, unmap
 544		 * the first skb's frags
 545		 */
 546		if (first_shinfo) {
 547			for (j = 0; j < first_shinfo->nr_frags; j++) {
 548				pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
 549				xenvif_idx_unmap(queue, pending_idx);
 550				xenvif_idx_release(queue, pending_idx,
 551						   XEN_NETIF_RSP_OKAY);
 552			}
 553		}
 554
 555		/* Remember the error: invalidate all subsequent fragments. */
 556		err = newerr;
 557	}
 558
 559	if (skb_has_frag_list(skb) && !first_shinfo) {
 560		first_shinfo = shinfo;
 561		shinfo = skb_shinfo(shinfo->frag_list);
 562		nr_frags = shinfo->nr_frags;
 563
 564		goto check_frags;
 565	}
 566
 567	*gopp_map = gop_map;
 568	return err;
 569}
 570
 571static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
 572{
 573	struct skb_shared_info *shinfo = skb_shinfo(skb);
 574	int nr_frags = shinfo->nr_frags;
 575	int i;
 576	u16 prev_pending_idx = INVALID_PENDING_IDX;
 577
 578	for (i = 0; i < nr_frags; i++) {
 579		skb_frag_t *frag = shinfo->frags + i;
 580		struct xen_netif_tx_request *txp;
 581		struct page *page;
 582		u16 pending_idx;
 583
 584		pending_idx = frag_get_pending_idx(frag);
 585
 586		/* If this is not the first frag, chain it to the previous*/
 587		if (prev_pending_idx == INVALID_PENDING_IDX)
 588			skb_shinfo(skb)->destructor_arg =
 589				&callback_param(queue, pending_idx);
 590		else
 591			callback_param(queue, prev_pending_idx).ctx =
 592				&callback_param(queue, pending_idx);
 593
 594		callback_param(queue, pending_idx).ctx = NULL;
 595		prev_pending_idx = pending_idx;
 596
 597		txp = &queue->pending_tx_info[pending_idx].req;
 598		page = virt_to_page(idx_to_kaddr(queue, pending_idx));
 599		__skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
 600		skb->len += txp->size;
 601		skb->data_len += txp->size;
 602		skb->truesize += txp->size;
 603
 604		/* Take an extra reference to offset network stack's put_page */
 605		get_page(queue->mmap_pages[pending_idx]);
 606	}
 607}
 608
 609static int xenvif_get_extras(struct xenvif_queue *queue,
 610			     struct xen_netif_extra_info *extras,
 611			     unsigned int *extra_count,
 612			     int work_to_do)
 613{
 614	struct xen_netif_extra_info extra;
 615	RING_IDX cons = queue->tx.req_cons;
 616
 617	do {
 618		if (unlikely(work_to_do-- <= 0)) {
 619			netdev_err(queue->vif->dev, "Missing extra info\n");
 620			xenvif_fatal_tx_err(queue->vif);
 621			return -EBADR;
 622		}
 623
 624		RING_COPY_REQUEST(&queue->tx, cons, &extra);
 625
 626		queue->tx.req_cons = ++cons;
 627		(*extra_count)++;
 628
 629		if (unlikely(!extra.type ||
 630			     extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
 631			netdev_err(queue->vif->dev,
 632				   "Invalid extra type: %d\n", extra.type);
 633			xenvif_fatal_tx_err(queue->vif);
 634			return -EINVAL;
 635		}
 636
 637		memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
 638	} while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
 639
 640	return work_to_do;
 641}
 642
 643static int xenvif_set_skb_gso(struct xenvif *vif,
 644			      struct sk_buff *skb,
 645			      struct xen_netif_extra_info *gso)
 646{
 647	if (!gso->u.gso.size) {
 648		netdev_err(vif->dev, "GSO size must not be zero.\n");
 649		xenvif_fatal_tx_err(vif);
 650		return -EINVAL;
 651	}
 652
 653	switch (gso->u.gso.type) {
 654	case XEN_NETIF_GSO_TYPE_TCPV4:
 655		skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 656		break;
 657	case XEN_NETIF_GSO_TYPE_TCPV6:
 658		skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 659		break;
 660	default:
 661		netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
 662		xenvif_fatal_tx_err(vif);
 663		return -EINVAL;
 664	}
 665
 666	skb_shinfo(skb)->gso_size = gso->u.gso.size;
 667	/* gso_segs will be calculated later */
 668
 669	return 0;
 670}
 671
 672static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb)
 673{
 674	bool recalculate_partial_csum = false;
 675
 676	/* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
 677	 * peers can fail to set NETRXF_csum_blank when sending a GSO
 678	 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
 679	 * recalculate the partial checksum.
 680	 */
 681	if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
 682		queue->stats.rx_gso_checksum_fixup++;
 683		skb->ip_summed = CHECKSUM_PARTIAL;
 684		recalculate_partial_csum = true;
 685	}
 686
 687	/* A non-CHECKSUM_PARTIAL SKB does not require setup. */
 688	if (skb->ip_summed != CHECKSUM_PARTIAL)
 689		return 0;
 690
 691	return skb_checksum_setup(skb, recalculate_partial_csum);
 692}
 693
 694static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
 695{
 696	u64 now = get_jiffies_64();
 697	u64 next_credit = queue->credit_window_start +
 698		msecs_to_jiffies(queue->credit_usec / 1000);
 699
 700	/* Timer could already be pending in rare cases. */
 701	if (timer_pending(&queue->credit_timeout)) {
 702		queue->rate_limited = true;
 703		return true;
 704	}
 705
 706	/* Passed the point where we can replenish credit? */
 707	if (time_after_eq64(now, next_credit)) {
 708		queue->credit_window_start = now;
 709		tx_add_credit(queue);
 710	}
 711
 712	/* Still too big to send right now? Set a callback. */
 713	if (size > queue->remaining_credit) {
 714		mod_timer(&queue->credit_timeout,
 715			  next_credit);
 716		queue->credit_window_start = next_credit;
 717		queue->rate_limited = true;
 718
 719		return true;
 720	}
 721
 722	return false;
 723}
 724
 725/* No locking is required in xenvif_mcast_add/del() as they are
 726 * only ever invoked from NAPI poll. An RCU list is used because
 727 * xenvif_mcast_match() is called asynchronously, during start_xmit.
 728 */
 729
 730static int xenvif_mcast_add(struct xenvif *vif, const u8 *addr)
 731{
 732	struct xenvif_mcast_addr *mcast;
 733
 734	if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) {
 735		if (net_ratelimit())
 736			netdev_err(vif->dev,
 737				   "Too many multicast addresses\n");
 738		return -ENOSPC;
 739	}
 740
 741	mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC);
 742	if (!mcast)
 743		return -ENOMEM;
 744
 745	ether_addr_copy(mcast->addr, addr);
 746	list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr);
 747	vif->fe_mcast_count++;
 748
 749	return 0;
 750}
 751
 752static void xenvif_mcast_del(struct xenvif *vif, const u8 *addr)
 753{
 754	struct xenvif_mcast_addr *mcast;
 755
 756	list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
 757		if (ether_addr_equal(addr, mcast->addr)) {
 758			--vif->fe_mcast_count;
 759			list_del_rcu(&mcast->entry);
 760			kfree_rcu(mcast, rcu);
 761			break;
 762		}
 763	}
 764}
 765
 766bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr)
 767{
 768	struct xenvif_mcast_addr *mcast;
 769
 770	rcu_read_lock();
 771	list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
 772		if (ether_addr_equal(addr, mcast->addr)) {
 773			rcu_read_unlock();
 774			return true;
 775		}
 776	}
 777	rcu_read_unlock();
 778
 779	return false;
 780}
 781
 782void xenvif_mcast_addr_list_free(struct xenvif *vif)
 783{
 784	/* No need for locking or RCU here. NAPI poll and TX queue
 785	 * are stopped.
 786	 */
 787	while (!list_empty(&vif->fe_mcast_addr)) {
 788		struct xenvif_mcast_addr *mcast;
 789
 790		mcast = list_first_entry(&vif->fe_mcast_addr,
 791					 struct xenvif_mcast_addr,
 792					 entry);
 793		--vif->fe_mcast_count;
 794		list_del(&mcast->entry);
 795		kfree(mcast);
 796	}
 797}
 798
 799static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 800				     int budget,
 801				     unsigned *copy_ops,
 802				     unsigned *map_ops)
 803{
 804	struct gnttab_map_grant_ref *gop = queue->tx_map_ops;
 805	struct sk_buff *skb, *nskb;
 806	int ret;
 807	unsigned int frag_overflow;
 808
 809	while (skb_queue_len(&queue->tx_queue) < budget) {
 810		struct xen_netif_tx_request txreq;
 811		struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
 812		struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
 813		unsigned int extra_count;
 814		u16 pending_idx;
 815		RING_IDX idx;
 816		int work_to_do;
 817		unsigned int data_len;
 818		pending_ring_idx_t index;
 819
 820		if (queue->tx.sring->req_prod - queue->tx.req_cons >
 821		    XEN_NETIF_TX_RING_SIZE) {
 822			netdev_err(queue->vif->dev,
 823				   "Impossible number of requests. "
 824				   "req_prod %d, req_cons %d, size %ld\n",
 825				   queue->tx.sring->req_prod, queue->tx.req_cons,
 826				   XEN_NETIF_TX_RING_SIZE);
 827			xenvif_fatal_tx_err(queue->vif);
 828			break;
 829		}
 830
 831		work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
 832		if (!work_to_do)
 833			break;
 834
 835		idx = queue->tx.req_cons;
 836		rmb(); /* Ensure that we see the request before we copy it. */
 837		RING_COPY_REQUEST(&queue->tx, idx, &txreq);
 838
 839		/* Credit-based scheduling. */
 840		if (txreq.size > queue->remaining_credit &&
 841		    tx_credit_exceeded(queue, txreq.size))
 842			break;
 843
 844		queue->remaining_credit -= txreq.size;
 845
 846		work_to_do--;
 847		queue->tx.req_cons = ++idx;
 848
 849		memset(extras, 0, sizeof(extras));
 850		extra_count = 0;
 851		if (txreq.flags & XEN_NETTXF_extra_info) {
 852			work_to_do = xenvif_get_extras(queue, extras,
 853						       &extra_count,
 854						       work_to_do);
 855			idx = queue->tx.req_cons;
 856			if (unlikely(work_to_do < 0))
 857				break;
 858		}
 859
 860		if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) {
 861			struct xen_netif_extra_info *extra;
 862
 863			extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
 864			ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
 865
 866			make_tx_response(queue, &txreq, extra_count,
 867					 (ret == 0) ?
 868					 XEN_NETIF_RSP_OKAY :
 869					 XEN_NETIF_RSP_ERROR);
 870			push_tx_responses(queue);
 871			continue;
 872		}
 873
 874		if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) {
 875			struct xen_netif_extra_info *extra;
 876
 877			extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
 878			xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
 879
 880			make_tx_response(queue, &txreq, extra_count,
 881					 XEN_NETIF_RSP_OKAY);
 882			push_tx_responses(queue);
 883			continue;
 884		}
 885
 886		ret = xenvif_count_requests(queue, &txreq, extra_count,
 887					    txfrags, work_to_do);
 888		if (unlikely(ret < 0))
 889			break;
 890
 891		idx += ret;
 892
 893		if (unlikely(txreq.size < ETH_HLEN)) {
 894			netdev_dbg(queue->vif->dev,
 895				   "Bad packet size: %d\n", txreq.size);
 896			xenvif_tx_err(queue, &txreq, extra_count, idx);
 897			break;
 898		}
 899
 900		/* No crossing a page as the payload mustn't fragment. */
 901		if (unlikely((txreq.offset + txreq.size) > XEN_PAGE_SIZE)) {
 902			netdev_err(queue->vif->dev,
 903				   "txreq.offset: %u, size: %u, end: %lu\n",
 904				   txreq.offset, txreq.size,
 905				   (unsigned long)(txreq.offset&~XEN_PAGE_MASK) + txreq.size);
 906			xenvif_fatal_tx_err(queue->vif);
 907			break;
 908		}
 909
 910		index = pending_index(queue->pending_cons);
 911		pending_idx = queue->pending_ring[index];
 912
 913		data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN &&
 914			    ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
 915			XEN_NETBACK_TX_COPY_LEN : txreq.size;
 916
 917		skb = xenvif_alloc_skb(data_len);
 918		if (unlikely(skb == NULL)) {
 919			netdev_dbg(queue->vif->dev,
 920				   "Can't allocate a skb in start_xmit.\n");
 921			xenvif_tx_err(queue, &txreq, extra_count, idx);
 922			break;
 923		}
 924
 925		skb_shinfo(skb)->nr_frags = ret;
 926		if (data_len < txreq.size)
 927			skb_shinfo(skb)->nr_frags++;
 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		frag_overflow = 0;
 932		nskb = NULL;
 933		if (skb_shinfo(skb)->nr_frags > MAX_SKB_FRAGS) {
 934			frag_overflow = skb_shinfo(skb)->nr_frags - MAX_SKB_FRAGS;
 935			BUG_ON(frag_overflow > MAX_SKB_FRAGS);
 936			skb_shinfo(skb)->nr_frags = MAX_SKB_FRAGS;
 937			nskb = xenvif_alloc_skb(0);
 938			if (unlikely(nskb == NULL)) {
 939				skb_shinfo(skb)->nr_frags = 0;
 940				kfree_skb(skb);
 941				xenvif_tx_err(queue, &txreq, extra_count, idx);
 942				if (net_ratelimit())
 943					netdev_err(queue->vif->dev,
 944						   "Can't allocate the frag_list skb.\n");
 945				break;
 946			}
 947		}
 948
 949		if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
 950			struct xen_netif_extra_info *gso;
 951			gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
 952
 953			if (xenvif_set_skb_gso(queue->vif, skb, gso)) {
 954				/* Failure in xenvif_set_skb_gso is fatal. */
 955				skb_shinfo(skb)->nr_frags = 0;
 956				kfree_skb(skb);
 957				kfree_skb(nskb);
 958				break;
 959			}
 960		}
 961
 962		if (extras[XEN_NETIF_EXTRA_TYPE_HASH - 1].type) {
 963			struct xen_netif_extra_info *extra;
 964			enum pkt_hash_types type = PKT_HASH_TYPE_NONE;
 965
 966			extra = &extras[XEN_NETIF_EXTRA_TYPE_HASH - 1];
 967
 968			switch (extra->u.hash.type) {
 969			case _XEN_NETIF_CTRL_HASH_TYPE_IPV4:
 970			case _XEN_NETIF_CTRL_HASH_TYPE_IPV6:
 971				type = PKT_HASH_TYPE_L3;
 972				break;
 973
 974			case _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP:
 975			case _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP:
 976				type = PKT_HASH_TYPE_L4;
 977				break;
 978
 979			default:
 980				break;
 981			}
 982
 983			if (type != PKT_HASH_TYPE_NONE)
 984				skb_set_hash(skb,
 985					     *(u32 *)extra->u.hash.value,
 986					     type);
 987		}
 988
 989		XENVIF_TX_CB(skb)->pending_idx = pending_idx;
 990
 991		__skb_put(skb, data_len);
 992		queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
 993		queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid;
 994		queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
 995
 996		queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
 997			virt_to_gfn(skb->data);
 998		queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
 999		queue->tx_copy_ops[*copy_ops].dest.offset =
1000			offset_in_page(skb->data) & ~XEN_PAGE_MASK;
1001
1002		queue->tx_copy_ops[*copy_ops].len = data_len;
1003		queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
1004
1005		(*copy_ops)++;
1006
1007		if (data_len < txreq.size) {
1008			frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1009					     pending_idx);
1010			xenvif_tx_create_map_op(queue, pending_idx, &txreq,
1011						extra_count, gop);
1012			gop++;
1013		} else {
1014			frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1015					     INVALID_PENDING_IDX);
1016			memcpy(&queue->pending_tx_info[pending_idx].req,
1017			       &txreq, sizeof(txreq));
1018			queue->pending_tx_info[pending_idx].extra_count =
1019				extra_count;
1020		}
1021
1022		queue->pending_cons++;
1023
1024		gop = xenvif_get_requests(queue, skb, txfrags, gop,
1025				          frag_overflow, nskb);
1026
1027		__skb_queue_tail(&queue->tx_queue, skb);
1028
1029		queue->tx.req_cons = idx;
1030
1031		if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) ||
1032		    (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
1033			break;
1034	}
1035
1036	(*map_ops) = gop - queue->tx_map_ops;
1037	return;
1038}
1039
1040/* Consolidate skb with a frag_list into a brand new one with local pages on
1041 * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1042 */
1043static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb)
1044{
1045	unsigned int offset = skb_headlen(skb);
1046	skb_frag_t frags[MAX_SKB_FRAGS];
1047	int i, f;
1048	struct ubuf_info *uarg;
1049	struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1050
1051	queue->stats.tx_zerocopy_sent += 2;
1052	queue->stats.tx_frag_overflow++;
1053
1054	xenvif_fill_frags(queue, nskb);
1055	/* Subtract frags size, we will correct it later */
1056	skb->truesize -= skb->data_len;
1057	skb->len += nskb->len;
1058	skb->data_len += nskb->len;
1059
1060	/* create a brand new frags array and coalesce there */
1061	for (i = 0; offset < skb->len; i++) {
1062		struct page *page;
1063		unsigned int len;
1064
1065		BUG_ON(i >= MAX_SKB_FRAGS);
1066		page = alloc_page(GFP_ATOMIC);
1067		if (!page) {
1068			int j;
1069			skb->truesize += skb->data_len;
1070			for (j = 0; j < i; j++)
1071				put_page(skb_frag_page(&frags[j]));
1072			return -ENOMEM;
1073		}
1074
1075		if (offset + PAGE_SIZE < skb->len)
1076			len = PAGE_SIZE;
1077		else
1078			len = skb->len - offset;
1079		if (skb_copy_bits(skb, offset, page_address(page), len))
1080			BUG();
1081
1082		offset += len;
1083		__skb_frag_set_page(&frags[i], page);
1084		skb_frag_off_set(&frags[i], 0);
1085		skb_frag_size_set(&frags[i], len);
1086	}
1087
1088	/* Release all the original (foreign) frags. */
1089	for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
1090		skb_frag_unref(skb, f);
1091	uarg = skb_shinfo(skb)->destructor_arg;
1092	/* increase inflight counter to offset decrement in callback */
1093	atomic_inc(&queue->inflight_packets);
1094	uarg->callback(NULL, uarg, true);
1095	skb_shinfo(skb)->destructor_arg = NULL;
1096
1097	/* Fill the skb with the new (local) frags. */
1098	memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t));
1099	skb_shinfo(skb)->nr_frags = i;
1100	skb->truesize += i * PAGE_SIZE;
1101
1102	return 0;
1103}
1104
1105static int xenvif_tx_submit(struct xenvif_queue *queue)
1106{
1107	struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops;
1108	struct gnttab_copy *gop_copy = queue->tx_copy_ops;
1109	struct sk_buff *skb;
1110	int work_done = 0;
1111
1112	while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
1113		struct xen_netif_tx_request *txp;
1114		u16 pending_idx;
1115		unsigned data_len;
1116
1117		pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1118		txp = &queue->pending_tx_info[pending_idx].req;
1119
1120		/* Check the remap error code. */
1121		if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
1122			/* If there was an error, xenvif_tx_check_gop is
1123			 * expected to release all the frags which were mapped,
1124			 * so kfree_skb shouldn't do it again
1125			 */
1126			skb_shinfo(skb)->nr_frags = 0;
1127			if (skb_has_frag_list(skb)) {
1128				struct sk_buff *nskb =
1129						skb_shinfo(skb)->frag_list;
1130				skb_shinfo(nskb)->nr_frags = 0;
1131			}
1132			kfree_skb(skb);
1133			continue;
1134		}
1135
1136		data_len = skb->len;
1137		callback_param(queue, pending_idx).ctx = NULL;
1138		if (data_len < txp->size) {
1139			/* Append the packet payload as a fragment. */
1140			txp->offset += data_len;
1141			txp->size -= data_len;
1142		} else {
1143			/* Schedule a response immediately. */
1144			xenvif_idx_release(queue, pending_idx,
1145					   XEN_NETIF_RSP_OKAY);
1146		}
1147
1148		if (txp->flags & XEN_NETTXF_csum_blank)
1149			skb->ip_summed = CHECKSUM_PARTIAL;
1150		else if (txp->flags & XEN_NETTXF_data_validated)
1151			skb->ip_summed = CHECKSUM_UNNECESSARY;
1152
1153		xenvif_fill_frags(queue, skb);
1154
1155		if (unlikely(skb_has_frag_list(skb))) {
1156			struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1157			xenvif_skb_zerocopy_prepare(queue, nskb);
1158			if (xenvif_handle_frag_list(queue, skb)) {
1159				if (net_ratelimit())
1160					netdev_err(queue->vif->dev,
1161						   "Not enough memory to consolidate frag_list!\n");
1162				xenvif_skb_zerocopy_prepare(queue, skb);
1163				kfree_skb(skb);
1164				continue;
1165			}
1166			/* Copied all the bits from the frag list -- free it. */
1167			skb_frag_list_init(skb);
1168			kfree_skb(nskb);
1169		}
1170
1171		skb->dev      = queue->vif->dev;
1172		skb->protocol = eth_type_trans(skb, skb->dev);
1173		skb_reset_network_header(skb);
1174
1175		if (checksum_setup(queue, skb)) {
1176			netdev_dbg(queue->vif->dev,
1177				   "Can't setup checksum in net_tx_action\n");
1178			/* We have to set this flag to trigger the callback */
1179			if (skb_shinfo(skb)->destructor_arg)
1180				xenvif_skb_zerocopy_prepare(queue, skb);
1181			kfree_skb(skb);
1182			continue;
1183		}
1184
1185		skb_probe_transport_header(skb);
1186
1187		/* If the packet is GSO then we will have just set up the
1188		 * transport header offset in checksum_setup so it's now
1189		 * straightforward to calculate gso_segs.
1190		 */
1191		if (skb_is_gso(skb)) {
1192			int mss, hdrlen;
1193
1194			/* GSO implies having the L4 header. */
1195			WARN_ON_ONCE(!skb_transport_header_was_set(skb));
1196			if (unlikely(!skb_transport_header_was_set(skb))) {
1197				kfree_skb(skb);
1198				continue;
1199			}
1200
1201			mss = skb_shinfo(skb)->gso_size;
1202			hdrlen = skb_transport_header(skb) -
1203				skb_mac_header(skb) +
1204				tcp_hdrlen(skb);
1205
1206			skb_shinfo(skb)->gso_segs =
1207				DIV_ROUND_UP(skb->len - hdrlen, mss);
1208		}
1209
1210		queue->stats.rx_bytes += skb->len;
1211		queue->stats.rx_packets++;
1212
1213		work_done++;
1214
1215		/* Set this flag right before netif_receive_skb, otherwise
1216		 * someone might think this packet already left netback, and
1217		 * do a skb_copy_ubufs while we are still in control of the
1218		 * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1219		 */
1220		if (skb_shinfo(skb)->destructor_arg) {
1221			xenvif_skb_zerocopy_prepare(queue, skb);
1222			queue->stats.tx_zerocopy_sent++;
1223		}
1224
1225		netif_receive_skb(skb);
1226	}
1227
1228	return work_done;
1229}
1230
1231void xenvif_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *ubuf,
1232			      bool zerocopy_success)
1233{
1234	unsigned long flags;
1235	pending_ring_idx_t index;
1236	struct xenvif_queue *queue = ubuf_to_queue(ubuf);
1237
1238	/* This is the only place where we grab this lock, to protect callbacks
1239	 * from each other.
1240	 */
1241	spin_lock_irqsave(&queue->callback_lock, flags);
1242	do {
1243		u16 pending_idx = ubuf->desc;
1244		ubuf = (struct ubuf_info *) ubuf->ctx;
1245		BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
1246			MAX_PENDING_REQS);
1247		index = pending_index(queue->dealloc_prod);
1248		queue->dealloc_ring[index] = pending_idx;
1249		/* Sync with xenvif_tx_dealloc_action:
1250		 * insert idx then incr producer.
1251		 */
1252		smp_wmb();
1253		queue->dealloc_prod++;
1254	} while (ubuf);
1255	spin_unlock_irqrestore(&queue->callback_lock, flags);
1256
1257	if (likely(zerocopy_success))
1258		queue->stats.tx_zerocopy_success++;
1259	else
1260		queue->stats.tx_zerocopy_fail++;
1261	xenvif_skb_zerocopy_complete(queue);
1262}
1263
1264static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
1265{
1266	struct gnttab_unmap_grant_ref *gop;
1267	pending_ring_idx_t dc, dp;
1268	u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1269	unsigned int i = 0;
1270
1271	dc = queue->dealloc_cons;
1272	gop = queue->tx_unmap_ops;
1273
1274	/* Free up any grants we have finished using */
1275	do {
1276		dp = queue->dealloc_prod;
1277
1278		/* Ensure we see all indices enqueued by all
1279		 * xenvif_zerocopy_callback().
1280		 */
1281		smp_rmb();
1282
1283		while (dc != dp) {
1284			BUG_ON(gop - queue->tx_unmap_ops >= MAX_PENDING_REQS);
1285			pending_idx =
1286				queue->dealloc_ring[pending_index(dc++)];
1287
1288			pending_idx_release[gop - queue->tx_unmap_ops] =
1289				pending_idx;
1290			queue->pages_to_unmap[gop - queue->tx_unmap_ops] =
1291				queue->mmap_pages[pending_idx];
1292			gnttab_set_unmap_op(gop,
1293					    idx_to_kaddr(queue, pending_idx),
1294					    GNTMAP_host_map,
1295					    queue->grant_tx_handle[pending_idx]);
1296			xenvif_grant_handle_reset(queue, pending_idx);
1297			++gop;
1298		}
1299
1300	} while (dp != queue->dealloc_prod);
1301
1302	queue->dealloc_cons = dc;
1303
1304	if (gop - queue->tx_unmap_ops > 0) {
1305		int ret;
1306		ret = gnttab_unmap_refs(queue->tx_unmap_ops,
1307					NULL,
1308					queue->pages_to_unmap,
1309					gop - queue->tx_unmap_ops);
1310		if (ret) {
1311			netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tu ret %d\n",
1312				   gop - queue->tx_unmap_ops, ret);
1313			for (i = 0; i < gop - queue->tx_unmap_ops; ++i) {
1314				if (gop[i].status != GNTST_okay)
1315					netdev_err(queue->vif->dev,
1316						   " host_addr: 0x%llx handle: 0x%x status: %d\n",
1317						   gop[i].host_addr,
1318						   gop[i].handle,
1319						   gop[i].status);
1320			}
1321			BUG();
1322		}
1323	}
1324
1325	for (i = 0; i < gop - queue->tx_unmap_ops; ++i)
1326		xenvif_idx_release(queue, pending_idx_release[i],
1327				   XEN_NETIF_RSP_OKAY);
1328}
1329
1330
1331/* Called after netfront has transmitted */
1332int xenvif_tx_action(struct xenvif_queue *queue, int budget)
1333{
1334	unsigned nr_mops, nr_cops = 0;
1335	int work_done, ret;
1336
1337	if (unlikely(!tx_work_todo(queue)))
1338		return 0;
1339
1340	xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops);
1341
1342	if (nr_cops == 0)
1343		return 0;
1344
1345	gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
1346	if (nr_mops != 0) {
1347		ret = gnttab_map_refs(queue->tx_map_ops,
1348				      NULL,
1349				      queue->pages_to_map,
1350				      nr_mops);
1351		if (ret) {
1352			unsigned int i;
1353
1354			netdev_err(queue->vif->dev, "Map fail: nr %u ret %d\n",
1355				   nr_mops, ret);
1356			for (i = 0; i < nr_mops; ++i)
1357				WARN_ON_ONCE(queue->tx_map_ops[i].status ==
1358				             GNTST_okay);
1359		}
1360	}
1361
1362	work_done = xenvif_tx_submit(queue);
1363
1364	return work_done;
1365}
1366
1367static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
1368			       u8 status)
1369{
1370	struct pending_tx_info *pending_tx_info;
1371	pending_ring_idx_t index;
1372	unsigned long flags;
1373
1374	pending_tx_info = &queue->pending_tx_info[pending_idx];
1375
1376	spin_lock_irqsave(&queue->response_lock, flags);
1377
1378	make_tx_response(queue, &pending_tx_info->req,
1379			 pending_tx_info->extra_count, status);
1380
1381	/* Release the pending index before pusing the Tx response so
1382	 * its available before a new Tx request is pushed by the
1383	 * frontend.
1384	 */
1385	index = pending_index(queue->pending_prod++);
1386	queue->pending_ring[index] = pending_idx;
1387
1388	push_tx_responses(queue);
1389
1390	spin_unlock_irqrestore(&queue->response_lock, flags);
1391}
1392
1393
1394static void make_tx_response(struct xenvif_queue *queue,
1395			     struct xen_netif_tx_request *txp,
1396			     unsigned int extra_count,
1397			     s8       st)
1398{
1399	RING_IDX i = queue->tx.rsp_prod_pvt;
1400	struct xen_netif_tx_response *resp;
1401
1402	resp = RING_GET_RESPONSE(&queue->tx, i);
1403	resp->id     = txp->id;
1404	resp->status = st;
1405
1406	while (extra_count-- != 0)
1407		RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1408
1409	queue->tx.rsp_prod_pvt = ++i;
1410}
1411
1412static void push_tx_responses(struct xenvif_queue *queue)
1413{
1414	int notify;
1415
1416	RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
1417	if (notify)
1418		notify_remote_via_irq(queue->tx_irq);
1419}
1420
1421void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
1422{
1423	int ret;
1424	struct gnttab_unmap_grant_ref tx_unmap_op;
1425
1426	gnttab_set_unmap_op(&tx_unmap_op,
1427			    idx_to_kaddr(queue, pending_idx),
1428			    GNTMAP_host_map,
1429			    queue->grant_tx_handle[pending_idx]);
1430	xenvif_grant_handle_reset(queue, pending_idx);
1431
1432	ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1433				&queue->mmap_pages[pending_idx], 1);
1434	if (ret) {
1435		netdev_err(queue->vif->dev,
1436			   "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: 0x%x status: %d\n",
1437			   ret,
1438			   pending_idx,
1439			   tx_unmap_op.host_addr,
1440			   tx_unmap_op.handle,
1441			   tx_unmap_op.status);
1442		BUG();
1443	}
1444}
1445
1446static inline int tx_work_todo(struct xenvif_queue *queue)
1447{
1448	if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
1449		return 1;
1450
1451	return 0;
1452}
1453
1454static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
1455{
1456	return queue->dealloc_cons != queue->dealloc_prod;
1457}
1458
1459void xenvif_unmap_frontend_data_rings(struct xenvif_queue *queue)
1460{
1461	if (queue->tx.sring)
1462		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1463					queue->tx.sring);
1464	if (queue->rx.sring)
1465		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1466					queue->rx.sring);
1467}
1468
1469int xenvif_map_frontend_data_rings(struct xenvif_queue *queue,
1470				   grant_ref_t tx_ring_ref,
1471				   grant_ref_t rx_ring_ref)
1472{
1473	void *addr;
1474	struct xen_netif_tx_sring *txs;
1475	struct xen_netif_rx_sring *rxs;
1476	RING_IDX rsp_prod, req_prod;
1477	int err = -ENOMEM;
1478
1479	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1480				     &tx_ring_ref, 1, &addr);
1481	if (err)
1482		goto err;
1483
1484	txs = (struct xen_netif_tx_sring *)addr;
1485	rsp_prod = READ_ONCE(txs->rsp_prod);
1486	req_prod = READ_ONCE(txs->req_prod);
1487
1488	BACK_RING_ATTACH(&queue->tx, txs, rsp_prod, XEN_PAGE_SIZE);
1489
1490	err = -EIO;
1491	if (req_prod - rsp_prod > RING_SIZE(&queue->tx))
1492		goto err;
1493
1494	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1495				     &rx_ring_ref, 1, &addr);
1496	if (err)
1497		goto err;
1498
1499	rxs = (struct xen_netif_rx_sring *)addr;
1500	rsp_prod = READ_ONCE(rxs->rsp_prod);
1501	req_prod = READ_ONCE(rxs->req_prod);
1502
1503	BACK_RING_ATTACH(&queue->rx, rxs, rsp_prod, XEN_PAGE_SIZE);
1504
1505	err = -EIO;
1506	if (req_prod - rsp_prod > RING_SIZE(&queue->rx))
1507		goto err;
1508
1509	return 0;
1510
1511err:
1512	xenvif_unmap_frontend_data_rings(queue);
1513	return err;
1514}
1515
1516static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue)
1517{
1518	/* Dealloc thread must remain running until all inflight
1519	 * packets complete.
1520	 */
1521	return kthread_should_stop() &&
1522		!atomic_read(&queue->inflight_packets);
1523}
1524
1525int xenvif_dealloc_kthread(void *data)
1526{
1527	struct xenvif_queue *queue = data;
1528
1529	for (;;) {
1530		wait_event_interruptible(queue->dealloc_wq,
1531					 tx_dealloc_work_todo(queue) ||
1532					 xenvif_dealloc_kthread_should_stop(queue));
1533		if (xenvif_dealloc_kthread_should_stop(queue))
1534			break;
1535
1536		xenvif_tx_dealloc_action(queue);
1537		cond_resched();
1538	}
1539
1540	/* Unmap anything remaining*/
1541	if (tx_dealloc_work_todo(queue))
1542		xenvif_tx_dealloc_action(queue);
1543
1544	return 0;
1545}
1546
1547static void make_ctrl_response(struct xenvif *vif,
1548			       const struct xen_netif_ctrl_request *req,
1549			       u32 status, u32 data)
1550{
1551	RING_IDX idx = vif->ctrl.rsp_prod_pvt;
1552	struct xen_netif_ctrl_response rsp = {
1553		.id = req->id,
1554		.type = req->type,
1555		.status = status,
1556		.data = data,
1557	};
1558
1559	*RING_GET_RESPONSE(&vif->ctrl, idx) = rsp;
1560	vif->ctrl.rsp_prod_pvt = ++idx;
1561}
1562
1563static void push_ctrl_response(struct xenvif *vif)
1564{
1565	int notify;
1566
1567	RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->ctrl, notify);
1568	if (notify)
1569		notify_remote_via_irq(vif->ctrl_irq);
1570}
1571
1572static void process_ctrl_request(struct xenvif *vif,
1573				 const struct xen_netif_ctrl_request *req)
1574{
1575	u32 status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED;
1576	u32 data = 0;
1577
1578	switch (req->type) {
1579	case XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM:
1580		status = xenvif_set_hash_alg(vif, req->data[0]);
1581		break;
1582
1583	case XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS:
1584		status = xenvif_get_hash_flags(vif, &data);
1585		break;
1586
1587	case XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS:
1588		status = xenvif_set_hash_flags(vif, req->data[0]);
1589		break;
1590
1591	case XEN_NETIF_CTRL_TYPE_SET_HASH_KEY:
1592		status = xenvif_set_hash_key(vif, req->data[0],
1593					     req->data[1]);
1594		break;
1595
1596	case XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE:
1597		status = XEN_NETIF_CTRL_STATUS_SUCCESS;
1598		data = XEN_NETBK_MAX_HASH_MAPPING_SIZE;
1599		break;
1600
1601	case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE:
1602		status = xenvif_set_hash_mapping_size(vif,
1603						      req->data[0]);
1604		break;
1605
1606	case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING:
1607		status = xenvif_set_hash_mapping(vif, req->data[0],
1608						 req->data[1],
1609						 req->data[2]);
1610		break;
1611
1612	default:
1613		break;
1614	}
1615
1616	make_ctrl_response(vif, req, status, data);
1617	push_ctrl_response(vif);
1618}
1619
1620static void xenvif_ctrl_action(struct xenvif *vif)
1621{
1622	for (;;) {
1623		RING_IDX req_prod, req_cons;
1624
1625		req_prod = vif->ctrl.sring->req_prod;
1626		req_cons = vif->ctrl.req_cons;
1627
1628		/* Make sure we can see requests before we process them. */
1629		rmb();
1630
1631		if (req_cons == req_prod)
1632			break;
1633
1634		while (req_cons != req_prod) {
1635			struct xen_netif_ctrl_request req;
1636
1637			RING_COPY_REQUEST(&vif->ctrl, req_cons, &req);
1638			req_cons++;
1639
1640			process_ctrl_request(vif, &req);
1641		}
1642
1643		vif->ctrl.req_cons = req_cons;
1644		vif->ctrl.sring->req_event = req_cons + 1;
1645	}
1646}
1647
1648static bool xenvif_ctrl_work_todo(struct xenvif *vif)
1649{
1650	if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->ctrl)))
1651		return true;
1652
1653	return false;
1654}
1655
1656irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data)
1657{
1658	struct xenvif *vif = data;
1659	unsigned int eoi_flag = XEN_EOI_FLAG_SPURIOUS;
1660
1661	while (xenvif_ctrl_work_todo(vif)) {
1662		xenvif_ctrl_action(vif);
1663		eoi_flag = 0;
1664	}
1665
1666	xen_irq_lateeoi(irq, eoi_flag);
1667
1668	return IRQ_HANDLED;
1669}
1670
1671static int __init netback_init(void)
1672{
1673	int rc = 0;
1674
1675	if (!xen_domain())
1676		return -ENODEV;
1677
1678	/* Allow as many queues as there are CPUs but max. 8 if user has not
1679	 * specified a value.
1680	 */
1681	if (xenvif_max_queues == 0)
1682		xenvif_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
1683					  num_online_cpus());
1684
1685	if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
1686		pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
1687			fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
1688		fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
1689	}
1690
1691	rc = xenvif_xenbus_init();
1692	if (rc)
1693		goto failed_init;
1694
1695#ifdef CONFIG_DEBUG_FS
1696	xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
1697#endif /* CONFIG_DEBUG_FS */
1698
1699	return 0;
1700
1701failed_init:
1702	return rc;
1703}
1704
1705module_init(netback_init);
1706
1707static void __exit netback_fini(void)
1708{
1709#ifdef CONFIG_DEBUG_FS
1710	debugfs_remove_recursive(xen_netback_dbg_root);
1711#endif /* CONFIG_DEBUG_FS */
1712	xenvif_xenbus_fini();
1713}
1714module_exit(netback_fini);
1715
1716MODULE_LICENSE("Dual BSD/GPL");
1717MODULE_ALIAS("xen-backend:vif");