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