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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
99static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
100 u8 status);
101
102static void make_tx_response(struct xenvif_queue *queue,
103 struct xen_netif_tx_request *txp,
104 unsigned int extra_count,
105 s8 st);
106static void push_tx_responses(struct xenvif_queue *queue);
107
108static inline int tx_work_todo(struct xenvif_queue *queue);
109
110static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
111 u16 idx)
112{
113 return page_to_pfn(queue->mmap_pages[idx]);
114}
115
116static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
117 u16 idx)
118{
119 return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
120}
121
122#define callback_param(vif, pending_idx) \
123 (vif->pending_tx_info[pending_idx].callback_struct)
124
125/* Find the containing VIF's structure from a pointer in pending_tx_info array
126 */
127static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf)
128{
129 u16 pending_idx = ubuf->desc;
130 struct pending_tx_info *temp =
131 container_of(ubuf, struct pending_tx_info, callback_struct);
132 return container_of(temp - pending_idx,
133 struct xenvif_queue,
134 pending_tx_info[0]);
135}
136
137static u16 frag_get_pending_idx(skb_frag_t *frag)
138{
139 return (u16)frag->page_offset;
140}
141
142static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
143{
144 frag->page_offset = pending_idx;
145}
146
147static inline pending_ring_idx_t pending_index(unsigned i)
148{
149 return i & (MAX_PENDING_REQS-1);
150}
151
152void xenvif_kick_thread(struct xenvif_queue *queue)
153{
154 wake_up(&queue->wq);
155}
156
157void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
158{
159 int more_to_do;
160
161 RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
162
163 if (more_to_do)
164 napi_schedule(&queue->napi);
165}
166
167static void tx_add_credit(struct xenvif_queue *queue)
168{
169 unsigned long max_burst, max_credit;
170
171 /*
172 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
173 * Otherwise the interface can seize up due to insufficient credit.
174 */
175 max_burst = max(131072UL, queue->credit_bytes);
176
177 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
178 max_credit = queue->remaining_credit + queue->credit_bytes;
179 if (max_credit < queue->remaining_credit)
180 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
181
182 queue->remaining_credit = min(max_credit, max_burst);
183 queue->rate_limited = false;
184}
185
186void xenvif_tx_credit_callback(struct timer_list *t)
187{
188 struct xenvif_queue *queue = from_timer(queue, t, credit_timeout);
189 tx_add_credit(queue);
190 xenvif_napi_schedule_or_enable_events(queue);
191}
192
193static void xenvif_tx_err(struct xenvif_queue *queue,
194 struct xen_netif_tx_request *txp,
195 unsigned int extra_count, RING_IDX end)
196{
197 RING_IDX cons = queue->tx.req_cons;
198 unsigned long flags;
199
200 do {
201 spin_lock_irqsave(&queue->response_lock, flags);
202 make_tx_response(queue, txp, extra_count, XEN_NETIF_RSP_ERROR);
203 push_tx_responses(queue);
204 spin_unlock_irqrestore(&queue->response_lock, flags);
205 if (cons == end)
206 break;
207 RING_COPY_REQUEST(&queue->tx, cons++, txp);
208 extra_count = 0; /* only the first frag can have extras */
209 } while (1);
210 queue->tx.req_cons = cons;
211}
212
213static void xenvif_fatal_tx_err(struct xenvif *vif)
214{
215 netdev_err(vif->dev, "fatal error; disabling device\n");
216 vif->disabled = true;
217 /* Disable the vif from queue 0's kthread */
218 if (vif->num_queues)
219 xenvif_kick_thread(&vif->queues[0]);
220}
221
222static int xenvif_count_requests(struct xenvif_queue *queue,
223 struct xen_netif_tx_request *first,
224 unsigned int extra_count,
225 struct xen_netif_tx_request *txp,
226 int work_to_do)
227{
228 RING_IDX cons = queue->tx.req_cons;
229 int slots = 0;
230 int drop_err = 0;
231 int more_data;
232
233 if (!(first->flags & XEN_NETTXF_more_data))
234 return 0;
235
236 do {
237 struct xen_netif_tx_request dropped_tx = { 0 };
238
239 if (slots >= work_to_do) {
240 netdev_err(queue->vif->dev,
241 "Asked for %d slots but exceeds this limit\n",
242 work_to_do);
243 xenvif_fatal_tx_err(queue->vif);
244 return -ENODATA;
245 }
246
247 /* This guest is really using too many slots and
248 * considered malicious.
249 */
250 if (unlikely(slots >= fatal_skb_slots)) {
251 netdev_err(queue->vif->dev,
252 "Malicious frontend using %d slots, threshold %u\n",
253 slots, fatal_skb_slots);
254 xenvif_fatal_tx_err(queue->vif);
255 return -E2BIG;
256 }
257
258 /* Xen network protocol had implicit dependency on
259 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
260 * the historical MAX_SKB_FRAGS value 18 to honor the
261 * same behavior as before. Any packet using more than
262 * 18 slots but less than fatal_skb_slots slots is
263 * dropped
264 */
265 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
266 if (net_ratelimit())
267 netdev_dbg(queue->vif->dev,
268 "Too many slots (%d) exceeding limit (%d), dropping packet\n",
269 slots, XEN_NETBK_LEGACY_SLOTS_MAX);
270 drop_err = -E2BIG;
271 }
272
273 if (drop_err)
274 txp = &dropped_tx;
275
276 RING_COPY_REQUEST(&queue->tx, cons + slots, txp);
277
278 /* If the guest submitted a frame >= 64 KiB then
279 * first->size overflowed and following slots will
280 * appear to be larger than the frame.
281 *
282 * This cannot be fatal error as there are buggy
283 * frontends that do this.
284 *
285 * Consume all slots and drop the packet.
286 */
287 if (!drop_err && txp->size > first->size) {
288 if (net_ratelimit())
289 netdev_dbg(queue->vif->dev,
290 "Invalid tx request, slot size %u > remaining size %u\n",
291 txp->size, first->size);
292 drop_err = -EIO;
293 }
294
295 first->size -= txp->size;
296 slots++;
297
298 if (unlikely((txp->offset + txp->size) > XEN_PAGE_SIZE)) {
299 netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %u, size: %u\n",
300 txp->offset, txp->size);
301 xenvif_fatal_tx_err(queue->vif);
302 return -EINVAL;
303 }
304
305 more_data = txp->flags & XEN_NETTXF_more_data;
306
307 if (!drop_err)
308 txp++;
309
310 } while (more_data);
311
312 if (drop_err) {
313 xenvif_tx_err(queue, first, extra_count, cons + slots);
314 return drop_err;
315 }
316
317 return slots;
318}
319
320
321struct xenvif_tx_cb {
322 u16 pending_idx;
323};
324
325#define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
326
327static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
328 u16 pending_idx,
329 struct xen_netif_tx_request *txp,
330 unsigned int extra_count,
331 struct gnttab_map_grant_ref *mop)
332{
333 queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
334 gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
335 GNTMAP_host_map | GNTMAP_readonly,
336 txp->gref, queue->vif->domid);
337
338 memcpy(&queue->pending_tx_info[pending_idx].req, txp,
339 sizeof(*txp));
340 queue->pending_tx_info[pending_idx].extra_count = extra_count;
341}
342
343static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
344{
345 struct sk_buff *skb =
346 alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
347 GFP_ATOMIC | __GFP_NOWARN);
348 if (unlikely(skb == NULL))
349 return NULL;
350
351 /* Packets passed to netif_rx() must have some headroom. */
352 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
353
354 /* Initialize it here to avoid later surprises */
355 skb_shinfo(skb)->destructor_arg = NULL;
356
357 return skb;
358}
359
360static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue,
361 struct sk_buff *skb,
362 struct xen_netif_tx_request *txp,
363 struct gnttab_map_grant_ref *gop,
364 unsigned int frag_overflow,
365 struct sk_buff *nskb)
366{
367 struct skb_shared_info *shinfo = skb_shinfo(skb);
368 skb_frag_t *frags = shinfo->frags;
369 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
370 int start;
371 pending_ring_idx_t index;
372 unsigned int nr_slots;
373
374 nr_slots = shinfo->nr_frags;
375
376 /* Skip first skb fragment if it is on same page as header fragment. */
377 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
378
379 for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
380 shinfo->nr_frags++, txp++, gop++) {
381 index = pending_index(queue->pending_cons++);
382 pending_idx = queue->pending_ring[index];
383 xenvif_tx_create_map_op(queue, pending_idx, txp, 0, gop);
384 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
385 }
386
387 if (frag_overflow) {
388
389 shinfo = skb_shinfo(nskb);
390 frags = shinfo->frags;
391
392 for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
393 shinfo->nr_frags++, txp++, gop++) {
394 index = pending_index(queue->pending_cons++);
395 pending_idx = queue->pending_ring[index];
396 xenvif_tx_create_map_op(queue, pending_idx, txp, 0,
397 gop);
398 frag_set_pending_idx(&frags[shinfo->nr_frags],
399 pending_idx);
400 }
401
402 skb_shinfo(skb)->frag_list = nskb;
403 }
404
405 return gop;
406}
407
408static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
409 u16 pending_idx,
410 grant_handle_t handle)
411{
412 if (unlikely(queue->grant_tx_handle[pending_idx] !=
413 NETBACK_INVALID_HANDLE)) {
414 netdev_err(queue->vif->dev,
415 "Trying to overwrite active handle! pending_idx: 0x%x\n",
416 pending_idx);
417 BUG();
418 }
419 queue->grant_tx_handle[pending_idx] = handle;
420}
421
422static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
423 u16 pending_idx)
424{
425 if (unlikely(queue->grant_tx_handle[pending_idx] ==
426 NETBACK_INVALID_HANDLE)) {
427 netdev_err(queue->vif->dev,
428 "Trying to unmap invalid handle! pending_idx: 0x%x\n",
429 pending_idx);
430 BUG();
431 }
432 queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
433}
434
435static int xenvif_tx_check_gop(struct xenvif_queue *queue,
436 struct sk_buff *skb,
437 struct gnttab_map_grant_ref **gopp_map,
438 struct gnttab_copy **gopp_copy)
439{
440 struct gnttab_map_grant_ref *gop_map = *gopp_map;
441 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
442 /* This always points to the shinfo of the skb being checked, which
443 * could be either the first or the one on the frag_list
444 */
445 struct skb_shared_info *shinfo = skb_shinfo(skb);
446 /* If this is non-NULL, we are currently checking the frag_list skb, and
447 * this points to the shinfo of the first one
448 */
449 struct skb_shared_info *first_shinfo = NULL;
450 int nr_frags = shinfo->nr_frags;
451 const bool sharedslot = nr_frags &&
452 frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
453 int i, err;
454
455 /* Check status of header. */
456 err = (*gopp_copy)->status;
457 if (unlikely(err)) {
458 if (net_ratelimit())
459 netdev_dbg(queue->vif->dev,
460 "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
461 (*gopp_copy)->status,
462 pending_idx,
463 (*gopp_copy)->source.u.ref);
464 /* The first frag might still have this slot mapped */
465 if (!sharedslot)
466 xenvif_idx_release(queue, pending_idx,
467 XEN_NETIF_RSP_ERROR);
468 }
469 (*gopp_copy)++;
470
471check_frags:
472 for (i = 0; i < nr_frags; i++, gop_map++) {
473 int j, newerr;
474
475 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
476
477 /* Check error status: if okay then remember grant handle. */
478 newerr = gop_map->status;
479
480 if (likely(!newerr)) {
481 xenvif_grant_handle_set(queue,
482 pending_idx,
483 gop_map->handle);
484 /* Had a previous error? Invalidate this fragment. */
485 if (unlikely(err)) {
486 xenvif_idx_unmap(queue, pending_idx);
487 /* If the mapping of the first frag was OK, but
488 * the header's copy failed, and they are
489 * sharing a slot, send an error
490 */
491 if (i == 0 && sharedslot)
492 xenvif_idx_release(queue, pending_idx,
493 XEN_NETIF_RSP_ERROR);
494 else
495 xenvif_idx_release(queue, pending_idx,
496 XEN_NETIF_RSP_OKAY);
497 }
498 continue;
499 }
500
501 /* Error on this fragment: respond to client with an error. */
502 if (net_ratelimit())
503 netdev_dbg(queue->vif->dev,
504 "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
505 i,
506 gop_map->status,
507 pending_idx,
508 gop_map->ref);
509
510 xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
511
512 /* Not the first error? Preceding frags already invalidated. */
513 if (err)
514 continue;
515
516 /* First error: if the header haven't shared a slot with the
517 * first frag, release it as well.
518 */
519 if (!sharedslot)
520 xenvif_idx_release(queue,
521 XENVIF_TX_CB(skb)->pending_idx,
522 XEN_NETIF_RSP_OKAY);
523
524 /* Invalidate preceding fragments of this skb. */
525 for (j = 0; j < i; j++) {
526 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
527 xenvif_idx_unmap(queue, pending_idx);
528 xenvif_idx_release(queue, pending_idx,
529 XEN_NETIF_RSP_OKAY);
530 }
531
532 /* And if we found the error while checking the frag_list, unmap
533 * the first skb's frags
534 */
535 if (first_shinfo) {
536 for (j = 0; j < first_shinfo->nr_frags; j++) {
537 pending_idx = frag_get_pending_idx(&first_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
544 /* Remember the error: invalidate all subsequent fragments. */
545 err = newerr;
546 }
547
548 if (skb_has_frag_list(skb) && !first_shinfo) {
549 first_shinfo = skb_shinfo(skb);
550 shinfo = skb_shinfo(skb_shinfo(skb)->frag_list);
551 nr_frags = shinfo->nr_frags;
552
553 goto check_frags;
554 }
555
556 *gopp_map = gop_map;
557 return err;
558}
559
560static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
561{
562 struct skb_shared_info *shinfo = skb_shinfo(skb);
563 int nr_frags = shinfo->nr_frags;
564 int i;
565 u16 prev_pending_idx = INVALID_PENDING_IDX;
566
567 for (i = 0; i < nr_frags; i++) {
568 skb_frag_t *frag = shinfo->frags + i;
569 struct xen_netif_tx_request *txp;
570 struct page *page;
571 u16 pending_idx;
572
573 pending_idx = frag_get_pending_idx(frag);
574
575 /* If this is not the first frag, chain it to the previous*/
576 if (prev_pending_idx == INVALID_PENDING_IDX)
577 skb_shinfo(skb)->destructor_arg =
578 &callback_param(queue, pending_idx);
579 else
580 callback_param(queue, prev_pending_idx).ctx =
581 &callback_param(queue, pending_idx);
582
583 callback_param(queue, pending_idx).ctx = NULL;
584 prev_pending_idx = pending_idx;
585
586 txp = &queue->pending_tx_info[pending_idx].req;
587 page = virt_to_page(idx_to_kaddr(queue, pending_idx));
588 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
589 skb->len += txp->size;
590 skb->data_len += txp->size;
591 skb->truesize += txp->size;
592
593 /* Take an extra reference to offset network stack's put_page */
594 get_page(queue->mmap_pages[pending_idx]);
595 }
596}
597
598static int xenvif_get_extras(struct xenvif_queue *queue,
599 struct xen_netif_extra_info *extras,
600 unsigned int *extra_count,
601 int work_to_do)
602{
603 struct xen_netif_extra_info extra;
604 RING_IDX cons = queue->tx.req_cons;
605
606 do {
607 if (unlikely(work_to_do-- <= 0)) {
608 netdev_err(queue->vif->dev, "Missing extra info\n");
609 xenvif_fatal_tx_err(queue->vif);
610 return -EBADR;
611 }
612
613 RING_COPY_REQUEST(&queue->tx, cons, &extra);
614
615 queue->tx.req_cons = ++cons;
616 (*extra_count)++;
617
618 if (unlikely(!extra.type ||
619 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
620 netdev_err(queue->vif->dev,
621 "Invalid extra type: %d\n", extra.type);
622 xenvif_fatal_tx_err(queue->vif);
623 return -EINVAL;
624 }
625
626 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
627 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
628
629 return work_to_do;
630}
631
632static int xenvif_set_skb_gso(struct xenvif *vif,
633 struct sk_buff *skb,
634 struct xen_netif_extra_info *gso)
635{
636 if (!gso->u.gso.size) {
637 netdev_err(vif->dev, "GSO size must not be zero.\n");
638 xenvif_fatal_tx_err(vif);
639 return -EINVAL;
640 }
641
642 switch (gso->u.gso.type) {
643 case XEN_NETIF_GSO_TYPE_TCPV4:
644 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
645 break;
646 case XEN_NETIF_GSO_TYPE_TCPV6:
647 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
648 break;
649 default:
650 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
651 xenvif_fatal_tx_err(vif);
652 return -EINVAL;
653 }
654
655 skb_shinfo(skb)->gso_size = gso->u.gso.size;
656 /* gso_segs will be calculated later */
657
658 return 0;
659}
660
661static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb)
662{
663 bool recalculate_partial_csum = false;
664
665 /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
666 * peers can fail to set NETRXF_csum_blank when sending a GSO
667 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
668 * recalculate the partial checksum.
669 */
670 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
671 queue->stats.rx_gso_checksum_fixup++;
672 skb->ip_summed = CHECKSUM_PARTIAL;
673 recalculate_partial_csum = true;
674 }
675
676 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
677 if (skb->ip_summed != CHECKSUM_PARTIAL)
678 return 0;
679
680 return skb_checksum_setup(skb, recalculate_partial_csum);
681}
682
683static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
684{
685 u64 now = get_jiffies_64();
686 u64 next_credit = queue->credit_window_start +
687 msecs_to_jiffies(queue->credit_usec / 1000);
688
689 /* Timer could already be pending in rare cases. */
690 if (timer_pending(&queue->credit_timeout)) {
691 queue->rate_limited = true;
692 return true;
693 }
694
695 /* Passed the point where we can replenish credit? */
696 if (time_after_eq64(now, next_credit)) {
697 queue->credit_window_start = now;
698 tx_add_credit(queue);
699 }
700
701 /* Still too big to send right now? Set a callback. */
702 if (size > queue->remaining_credit) {
703 mod_timer(&queue->credit_timeout,
704 next_credit);
705 queue->credit_window_start = next_credit;
706 queue->rate_limited = true;
707
708 return true;
709 }
710
711 return false;
712}
713
714/* No locking is required in xenvif_mcast_add/del() as they are
715 * only ever invoked from NAPI poll. An RCU list is used because
716 * xenvif_mcast_match() is called asynchronously, during start_xmit.
717 */
718
719static int xenvif_mcast_add(struct xenvif *vif, const u8 *addr)
720{
721 struct xenvif_mcast_addr *mcast;
722
723 if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) {
724 if (net_ratelimit())
725 netdev_err(vif->dev,
726 "Too many multicast addresses\n");
727 return -ENOSPC;
728 }
729
730 mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC);
731 if (!mcast)
732 return -ENOMEM;
733
734 ether_addr_copy(mcast->addr, addr);
735 list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr);
736 vif->fe_mcast_count++;
737
738 return 0;
739}
740
741static void xenvif_mcast_del(struct xenvif *vif, const u8 *addr)
742{
743 struct xenvif_mcast_addr *mcast;
744
745 list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
746 if (ether_addr_equal(addr, mcast->addr)) {
747 --vif->fe_mcast_count;
748 list_del_rcu(&mcast->entry);
749 kfree_rcu(mcast, rcu);
750 break;
751 }
752 }
753}
754
755bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr)
756{
757 struct xenvif_mcast_addr *mcast;
758
759 rcu_read_lock();
760 list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
761 if (ether_addr_equal(addr, mcast->addr)) {
762 rcu_read_unlock();
763 return true;
764 }
765 }
766 rcu_read_unlock();
767
768 return false;
769}
770
771void xenvif_mcast_addr_list_free(struct xenvif *vif)
772{
773 /* No need for locking or RCU here. NAPI poll and TX queue
774 * are stopped.
775 */
776 while (!list_empty(&vif->fe_mcast_addr)) {
777 struct xenvif_mcast_addr *mcast;
778
779 mcast = list_first_entry(&vif->fe_mcast_addr,
780 struct xenvif_mcast_addr,
781 entry);
782 --vif->fe_mcast_count;
783 list_del(&mcast->entry);
784 kfree(mcast);
785 }
786}
787
788static void xenvif_tx_build_gops(struct xenvif_queue *queue,
789 int budget,
790 unsigned *copy_ops,
791 unsigned *map_ops)
792{
793 struct gnttab_map_grant_ref *gop = queue->tx_map_ops;
794 struct sk_buff *skb, *nskb;
795 int ret;
796 unsigned int frag_overflow;
797
798 while (skb_queue_len(&queue->tx_queue) < budget) {
799 struct xen_netif_tx_request txreq;
800 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
801 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
802 unsigned int extra_count;
803 u16 pending_idx;
804 RING_IDX idx;
805 int work_to_do;
806 unsigned int data_len;
807 pending_ring_idx_t index;
808
809 if (queue->tx.sring->req_prod - queue->tx.req_cons >
810 XEN_NETIF_TX_RING_SIZE) {
811 netdev_err(queue->vif->dev,
812 "Impossible number of requests. "
813 "req_prod %d, req_cons %d, size %ld\n",
814 queue->tx.sring->req_prod, queue->tx.req_cons,
815 XEN_NETIF_TX_RING_SIZE);
816 xenvif_fatal_tx_err(queue->vif);
817 break;
818 }
819
820 work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
821 if (!work_to_do)
822 break;
823
824 idx = queue->tx.req_cons;
825 rmb(); /* Ensure that we see the request before we copy it. */
826 RING_COPY_REQUEST(&queue->tx, idx, &txreq);
827
828 /* Credit-based scheduling. */
829 if (txreq.size > queue->remaining_credit &&
830 tx_credit_exceeded(queue, txreq.size))
831 break;
832
833 queue->remaining_credit -= txreq.size;
834
835 work_to_do--;
836 queue->tx.req_cons = ++idx;
837
838 memset(extras, 0, sizeof(extras));
839 extra_count = 0;
840 if (txreq.flags & XEN_NETTXF_extra_info) {
841 work_to_do = xenvif_get_extras(queue, extras,
842 &extra_count,
843 work_to_do);
844 idx = queue->tx.req_cons;
845 if (unlikely(work_to_do < 0))
846 break;
847 }
848
849 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) {
850 struct xen_netif_extra_info *extra;
851
852 extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
853 ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
854
855 make_tx_response(queue, &txreq, extra_count,
856 (ret == 0) ?
857 XEN_NETIF_RSP_OKAY :
858 XEN_NETIF_RSP_ERROR);
859 push_tx_responses(queue);
860 continue;
861 }
862
863 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) {
864 struct xen_netif_extra_info *extra;
865
866 extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
867 xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
868
869 make_tx_response(queue, &txreq, extra_count,
870 XEN_NETIF_RSP_OKAY);
871 push_tx_responses(queue);
872 continue;
873 }
874
875 ret = xenvif_count_requests(queue, &txreq, extra_count,
876 txfrags, work_to_do);
877 if (unlikely(ret < 0))
878 break;
879
880 idx += ret;
881
882 if (unlikely(txreq.size < ETH_HLEN)) {
883 netdev_dbg(queue->vif->dev,
884 "Bad packet size: %d\n", txreq.size);
885 xenvif_tx_err(queue, &txreq, extra_count, idx);
886 break;
887 }
888
889 /* No crossing a page as the payload mustn't fragment. */
890 if (unlikely((txreq.offset + txreq.size) > XEN_PAGE_SIZE)) {
891 netdev_err(queue->vif->dev,
892 "txreq.offset: %u, size: %u, end: %lu\n",
893 txreq.offset, txreq.size,
894 (unsigned long)(txreq.offset&~XEN_PAGE_MASK) + txreq.size);
895 xenvif_fatal_tx_err(queue->vif);
896 break;
897 }
898
899 index = pending_index(queue->pending_cons);
900 pending_idx = queue->pending_ring[index];
901
902 data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN &&
903 ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
904 XEN_NETBACK_TX_COPY_LEN : txreq.size;
905
906 skb = xenvif_alloc_skb(data_len);
907 if (unlikely(skb == NULL)) {
908 netdev_dbg(queue->vif->dev,
909 "Can't allocate a skb in start_xmit.\n");
910 xenvif_tx_err(queue, &txreq, extra_count, idx);
911 break;
912 }
913
914 skb_shinfo(skb)->nr_frags = ret;
915 if (data_len < txreq.size)
916 skb_shinfo(skb)->nr_frags++;
917 /* At this point shinfo->nr_frags is in fact the number of
918 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
919 */
920 frag_overflow = 0;
921 nskb = NULL;
922 if (skb_shinfo(skb)->nr_frags > MAX_SKB_FRAGS) {
923 frag_overflow = skb_shinfo(skb)->nr_frags - MAX_SKB_FRAGS;
924 BUG_ON(frag_overflow > MAX_SKB_FRAGS);
925 skb_shinfo(skb)->nr_frags = MAX_SKB_FRAGS;
926 nskb = xenvif_alloc_skb(0);
927 if (unlikely(nskb == NULL)) {
928 kfree_skb(skb);
929 xenvif_tx_err(queue, &txreq, extra_count, idx);
930 if (net_ratelimit())
931 netdev_err(queue->vif->dev,
932 "Can't allocate the frag_list skb.\n");
933 break;
934 }
935 }
936
937 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
938 struct xen_netif_extra_info *gso;
939 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
940
941 if (xenvif_set_skb_gso(queue->vif, skb, gso)) {
942 /* Failure in xenvif_set_skb_gso is fatal. */
943 kfree_skb(skb);
944 kfree_skb(nskb);
945 break;
946 }
947 }
948
949 if (extras[XEN_NETIF_EXTRA_TYPE_HASH - 1].type) {
950 struct xen_netif_extra_info *extra;
951 enum pkt_hash_types type = PKT_HASH_TYPE_NONE;
952
953 extra = &extras[XEN_NETIF_EXTRA_TYPE_HASH - 1];
954
955 switch (extra->u.hash.type) {
956 case _XEN_NETIF_CTRL_HASH_TYPE_IPV4:
957 case _XEN_NETIF_CTRL_HASH_TYPE_IPV6:
958 type = PKT_HASH_TYPE_L3;
959 break;
960
961 case _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP:
962 case _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP:
963 type = PKT_HASH_TYPE_L4;
964 break;
965
966 default:
967 break;
968 }
969
970 if (type != PKT_HASH_TYPE_NONE)
971 skb_set_hash(skb,
972 *(u32 *)extra->u.hash.value,
973 type);
974 }
975
976 XENVIF_TX_CB(skb)->pending_idx = pending_idx;
977
978 __skb_put(skb, data_len);
979 queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
980 queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid;
981 queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
982
983 queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
984 virt_to_gfn(skb->data);
985 queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
986 queue->tx_copy_ops[*copy_ops].dest.offset =
987 offset_in_page(skb->data) & ~XEN_PAGE_MASK;
988
989 queue->tx_copy_ops[*copy_ops].len = data_len;
990 queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
991
992 (*copy_ops)++;
993
994 if (data_len < txreq.size) {
995 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
996 pending_idx);
997 xenvif_tx_create_map_op(queue, pending_idx, &txreq,
998 extra_count, gop);
999 gop++;
1000 } else {
1001 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1002 INVALID_PENDING_IDX);
1003 memcpy(&queue->pending_tx_info[pending_idx].req,
1004 &txreq, sizeof(txreq));
1005 queue->pending_tx_info[pending_idx].extra_count =
1006 extra_count;
1007 }
1008
1009 queue->pending_cons++;
1010
1011 gop = xenvif_get_requests(queue, skb, txfrags, gop,
1012 frag_overflow, nskb);
1013
1014 __skb_queue_tail(&queue->tx_queue, skb);
1015
1016 queue->tx.req_cons = idx;
1017
1018 if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) ||
1019 (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
1020 break;
1021 }
1022
1023 (*map_ops) = gop - queue->tx_map_ops;
1024 return;
1025}
1026
1027/* Consolidate skb with a frag_list into a brand new one with local pages on
1028 * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1029 */
1030static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb)
1031{
1032 unsigned int offset = skb_headlen(skb);
1033 skb_frag_t frags[MAX_SKB_FRAGS];
1034 int i, f;
1035 struct ubuf_info *uarg;
1036 struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1037
1038 queue->stats.tx_zerocopy_sent += 2;
1039 queue->stats.tx_frag_overflow++;
1040
1041 xenvif_fill_frags(queue, nskb);
1042 /* Subtract frags size, we will correct it later */
1043 skb->truesize -= skb->data_len;
1044 skb->len += nskb->len;
1045 skb->data_len += nskb->len;
1046
1047 /* create a brand new frags array and coalesce there */
1048 for (i = 0; offset < skb->len; i++) {
1049 struct page *page;
1050 unsigned int len;
1051
1052 BUG_ON(i >= MAX_SKB_FRAGS);
1053 page = alloc_page(GFP_ATOMIC);
1054 if (!page) {
1055 int j;
1056 skb->truesize += skb->data_len;
1057 for (j = 0; j < i; j++)
1058 put_page(frags[j].page.p);
1059 return -ENOMEM;
1060 }
1061
1062 if (offset + PAGE_SIZE < skb->len)
1063 len = PAGE_SIZE;
1064 else
1065 len = skb->len - offset;
1066 if (skb_copy_bits(skb, offset, page_address(page), len))
1067 BUG();
1068
1069 offset += len;
1070 frags[i].page.p = page;
1071 frags[i].page_offset = 0;
1072 skb_frag_size_set(&frags[i], len);
1073 }
1074
1075 /* Copied all the bits from the frag list -- free it. */
1076 skb_frag_list_init(skb);
1077 xenvif_skb_zerocopy_prepare(queue, nskb);
1078 kfree_skb(nskb);
1079
1080 /* Release all the original (foreign) frags. */
1081 for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
1082 skb_frag_unref(skb, f);
1083 uarg = skb_shinfo(skb)->destructor_arg;
1084 /* increase inflight counter to offset decrement in callback */
1085 atomic_inc(&queue->inflight_packets);
1086 uarg->callback(uarg, true);
1087 skb_shinfo(skb)->destructor_arg = NULL;
1088
1089 /* Fill the skb with the new (local) frags. */
1090 memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t));
1091 skb_shinfo(skb)->nr_frags = i;
1092 skb->truesize += i * PAGE_SIZE;
1093
1094 return 0;
1095}
1096
1097static int xenvif_tx_submit(struct xenvif_queue *queue)
1098{
1099 struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops;
1100 struct gnttab_copy *gop_copy = queue->tx_copy_ops;
1101 struct sk_buff *skb;
1102 int work_done = 0;
1103
1104 while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
1105 struct xen_netif_tx_request *txp;
1106 u16 pending_idx;
1107 unsigned data_len;
1108
1109 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1110 txp = &queue->pending_tx_info[pending_idx].req;
1111
1112 /* Check the remap error code. */
1113 if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
1114 /* If there was an error, xenvif_tx_check_gop is
1115 * expected to release all the frags which were mapped,
1116 * so kfree_skb shouldn't do it again
1117 */
1118 skb_shinfo(skb)->nr_frags = 0;
1119 if (skb_has_frag_list(skb)) {
1120 struct sk_buff *nskb =
1121 skb_shinfo(skb)->frag_list;
1122 skb_shinfo(nskb)->nr_frags = 0;
1123 }
1124 kfree_skb(skb);
1125 continue;
1126 }
1127
1128 data_len = skb->len;
1129 callback_param(queue, pending_idx).ctx = NULL;
1130 if (data_len < txp->size) {
1131 /* Append the packet payload as a fragment. */
1132 txp->offset += data_len;
1133 txp->size -= data_len;
1134 } else {
1135 /* Schedule a response immediately. */
1136 xenvif_idx_release(queue, pending_idx,
1137 XEN_NETIF_RSP_OKAY);
1138 }
1139
1140 if (txp->flags & XEN_NETTXF_csum_blank)
1141 skb->ip_summed = CHECKSUM_PARTIAL;
1142 else if (txp->flags & XEN_NETTXF_data_validated)
1143 skb->ip_summed = CHECKSUM_UNNECESSARY;
1144
1145 xenvif_fill_frags(queue, skb);
1146
1147 if (unlikely(skb_has_frag_list(skb))) {
1148 if (xenvif_handle_frag_list(queue, skb)) {
1149 if (net_ratelimit())
1150 netdev_err(queue->vif->dev,
1151 "Not enough memory to consolidate frag_list!\n");
1152 xenvif_skb_zerocopy_prepare(queue, skb);
1153 kfree_skb(skb);
1154 continue;
1155 }
1156 }
1157
1158 skb->dev = queue->vif->dev;
1159 skb->protocol = eth_type_trans(skb, skb->dev);
1160 skb_reset_network_header(skb);
1161
1162 if (checksum_setup(queue, skb)) {
1163 netdev_dbg(queue->vif->dev,
1164 "Can't setup checksum in net_tx_action\n");
1165 /* We have to set this flag to trigger the callback */
1166 if (skb_shinfo(skb)->destructor_arg)
1167 xenvif_skb_zerocopy_prepare(queue, skb);
1168 kfree_skb(skb);
1169 continue;
1170 }
1171
1172 skb_probe_transport_header(skb, 0);
1173
1174 /* If the packet is GSO then we will have just set up the
1175 * transport header offset in checksum_setup so it's now
1176 * straightforward to calculate gso_segs.
1177 */
1178 if (skb_is_gso(skb)) {
1179 int mss = skb_shinfo(skb)->gso_size;
1180 int hdrlen = skb_transport_header(skb) -
1181 skb_mac_header(skb) +
1182 tcp_hdrlen(skb);
1183
1184 skb_shinfo(skb)->gso_segs =
1185 DIV_ROUND_UP(skb->len - hdrlen, mss);
1186 }
1187
1188 queue->stats.rx_bytes += skb->len;
1189 queue->stats.rx_packets++;
1190
1191 work_done++;
1192
1193 /* Set this flag right before netif_receive_skb, otherwise
1194 * someone might think this packet already left netback, and
1195 * do a skb_copy_ubufs while we are still in control of the
1196 * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1197 */
1198 if (skb_shinfo(skb)->destructor_arg) {
1199 xenvif_skb_zerocopy_prepare(queue, skb);
1200 queue->stats.tx_zerocopy_sent++;
1201 }
1202
1203 netif_receive_skb(skb);
1204 }
1205
1206 return work_done;
1207}
1208
1209void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success)
1210{
1211 unsigned long flags;
1212 pending_ring_idx_t index;
1213 struct xenvif_queue *queue = ubuf_to_queue(ubuf);
1214
1215 /* This is the only place where we grab this lock, to protect callbacks
1216 * from each other.
1217 */
1218 spin_lock_irqsave(&queue->callback_lock, flags);
1219 do {
1220 u16 pending_idx = ubuf->desc;
1221 ubuf = (struct ubuf_info *) ubuf->ctx;
1222 BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
1223 MAX_PENDING_REQS);
1224 index = pending_index(queue->dealloc_prod);
1225 queue->dealloc_ring[index] = pending_idx;
1226 /* Sync with xenvif_tx_dealloc_action:
1227 * insert idx then incr producer.
1228 */
1229 smp_wmb();
1230 queue->dealloc_prod++;
1231 } while (ubuf);
1232 spin_unlock_irqrestore(&queue->callback_lock, flags);
1233
1234 if (likely(zerocopy_success))
1235 queue->stats.tx_zerocopy_success++;
1236 else
1237 queue->stats.tx_zerocopy_fail++;
1238 xenvif_skb_zerocopy_complete(queue);
1239}
1240
1241static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
1242{
1243 struct gnttab_unmap_grant_ref *gop;
1244 pending_ring_idx_t dc, dp;
1245 u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1246 unsigned int i = 0;
1247
1248 dc = queue->dealloc_cons;
1249 gop = queue->tx_unmap_ops;
1250
1251 /* Free up any grants we have finished using */
1252 do {
1253 dp = queue->dealloc_prod;
1254
1255 /* Ensure we see all indices enqueued by all
1256 * xenvif_zerocopy_callback().
1257 */
1258 smp_rmb();
1259
1260 while (dc != dp) {
1261 BUG_ON(gop - queue->tx_unmap_ops >= MAX_PENDING_REQS);
1262 pending_idx =
1263 queue->dealloc_ring[pending_index(dc++)];
1264
1265 pending_idx_release[gop - queue->tx_unmap_ops] =
1266 pending_idx;
1267 queue->pages_to_unmap[gop - queue->tx_unmap_ops] =
1268 queue->mmap_pages[pending_idx];
1269 gnttab_set_unmap_op(gop,
1270 idx_to_kaddr(queue, pending_idx),
1271 GNTMAP_host_map,
1272 queue->grant_tx_handle[pending_idx]);
1273 xenvif_grant_handle_reset(queue, pending_idx);
1274 ++gop;
1275 }
1276
1277 } while (dp != queue->dealloc_prod);
1278
1279 queue->dealloc_cons = dc;
1280
1281 if (gop - queue->tx_unmap_ops > 0) {
1282 int ret;
1283 ret = gnttab_unmap_refs(queue->tx_unmap_ops,
1284 NULL,
1285 queue->pages_to_unmap,
1286 gop - queue->tx_unmap_ops);
1287 if (ret) {
1288 netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tu ret %d\n",
1289 gop - queue->tx_unmap_ops, ret);
1290 for (i = 0; i < gop - queue->tx_unmap_ops; ++i) {
1291 if (gop[i].status != GNTST_okay)
1292 netdev_err(queue->vif->dev,
1293 " host_addr: 0x%llx handle: 0x%x status: %d\n",
1294 gop[i].host_addr,
1295 gop[i].handle,
1296 gop[i].status);
1297 }
1298 BUG();
1299 }
1300 }
1301
1302 for (i = 0; i < gop - queue->tx_unmap_ops; ++i)
1303 xenvif_idx_release(queue, pending_idx_release[i],
1304 XEN_NETIF_RSP_OKAY);
1305}
1306
1307
1308/* Called after netfront has transmitted */
1309int xenvif_tx_action(struct xenvif_queue *queue, int budget)
1310{
1311 unsigned nr_mops, nr_cops = 0;
1312 int work_done, ret;
1313
1314 if (unlikely(!tx_work_todo(queue)))
1315 return 0;
1316
1317 xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops);
1318
1319 if (nr_cops == 0)
1320 return 0;
1321
1322 gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
1323 if (nr_mops != 0) {
1324 ret = gnttab_map_refs(queue->tx_map_ops,
1325 NULL,
1326 queue->pages_to_map,
1327 nr_mops);
1328 BUG_ON(ret);
1329 }
1330
1331 work_done = xenvif_tx_submit(queue);
1332
1333 return work_done;
1334}
1335
1336static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
1337 u8 status)
1338{
1339 struct pending_tx_info *pending_tx_info;
1340 pending_ring_idx_t index;
1341 unsigned long flags;
1342
1343 pending_tx_info = &queue->pending_tx_info[pending_idx];
1344
1345 spin_lock_irqsave(&queue->response_lock, flags);
1346
1347 make_tx_response(queue, &pending_tx_info->req,
1348 pending_tx_info->extra_count, status);
1349
1350 /* Release the pending index before pusing the Tx response so
1351 * its available before a new Tx request is pushed by the
1352 * frontend.
1353 */
1354 index = pending_index(queue->pending_prod++);
1355 queue->pending_ring[index] = pending_idx;
1356
1357 push_tx_responses(queue);
1358
1359 spin_unlock_irqrestore(&queue->response_lock, flags);
1360}
1361
1362
1363static void make_tx_response(struct xenvif_queue *queue,
1364 struct xen_netif_tx_request *txp,
1365 unsigned int extra_count,
1366 s8 st)
1367{
1368 RING_IDX i = queue->tx.rsp_prod_pvt;
1369 struct xen_netif_tx_response *resp;
1370
1371 resp = RING_GET_RESPONSE(&queue->tx, i);
1372 resp->id = txp->id;
1373 resp->status = st;
1374
1375 while (extra_count-- != 0)
1376 RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1377
1378 queue->tx.rsp_prod_pvt = ++i;
1379}
1380
1381static void push_tx_responses(struct xenvif_queue *queue)
1382{
1383 int notify;
1384
1385 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
1386 if (notify)
1387 notify_remote_via_irq(queue->tx_irq);
1388}
1389
1390void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
1391{
1392 int ret;
1393 struct gnttab_unmap_grant_ref tx_unmap_op;
1394
1395 gnttab_set_unmap_op(&tx_unmap_op,
1396 idx_to_kaddr(queue, pending_idx),
1397 GNTMAP_host_map,
1398 queue->grant_tx_handle[pending_idx]);
1399 xenvif_grant_handle_reset(queue, pending_idx);
1400
1401 ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1402 &queue->mmap_pages[pending_idx], 1);
1403 if (ret) {
1404 netdev_err(queue->vif->dev,
1405 "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: 0x%x status: %d\n",
1406 ret,
1407 pending_idx,
1408 tx_unmap_op.host_addr,
1409 tx_unmap_op.handle,
1410 tx_unmap_op.status);
1411 BUG();
1412 }
1413}
1414
1415static inline int tx_work_todo(struct xenvif_queue *queue)
1416{
1417 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
1418 return 1;
1419
1420 return 0;
1421}
1422
1423static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
1424{
1425 return queue->dealloc_cons != queue->dealloc_prod;
1426}
1427
1428void xenvif_unmap_frontend_data_rings(struct xenvif_queue *queue)
1429{
1430 if (queue->tx.sring)
1431 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1432 queue->tx.sring);
1433 if (queue->rx.sring)
1434 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1435 queue->rx.sring);
1436}
1437
1438int xenvif_map_frontend_data_rings(struct xenvif_queue *queue,
1439 grant_ref_t tx_ring_ref,
1440 grant_ref_t rx_ring_ref)
1441{
1442 void *addr;
1443 struct xen_netif_tx_sring *txs;
1444 struct xen_netif_rx_sring *rxs;
1445
1446 int err = -ENOMEM;
1447
1448 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1449 &tx_ring_ref, 1, &addr);
1450 if (err)
1451 goto err;
1452
1453 txs = (struct xen_netif_tx_sring *)addr;
1454 BACK_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);
1455
1456 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1457 &rx_ring_ref, 1, &addr);
1458 if (err)
1459 goto err;
1460
1461 rxs = (struct xen_netif_rx_sring *)addr;
1462 BACK_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
1463
1464 return 0;
1465
1466err:
1467 xenvif_unmap_frontend_data_rings(queue);
1468 return err;
1469}
1470
1471static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue)
1472{
1473 /* Dealloc thread must remain running until all inflight
1474 * packets complete.
1475 */
1476 return kthread_should_stop() &&
1477 !atomic_read(&queue->inflight_packets);
1478}
1479
1480int xenvif_dealloc_kthread(void *data)
1481{
1482 struct xenvif_queue *queue = data;
1483
1484 for (;;) {
1485 wait_event_interruptible(queue->dealloc_wq,
1486 tx_dealloc_work_todo(queue) ||
1487 xenvif_dealloc_kthread_should_stop(queue));
1488 if (xenvif_dealloc_kthread_should_stop(queue))
1489 break;
1490
1491 xenvif_tx_dealloc_action(queue);
1492 cond_resched();
1493 }
1494
1495 /* Unmap anything remaining*/
1496 if (tx_dealloc_work_todo(queue))
1497 xenvif_tx_dealloc_action(queue);
1498
1499 return 0;
1500}
1501
1502static void make_ctrl_response(struct xenvif *vif,
1503 const struct xen_netif_ctrl_request *req,
1504 u32 status, u32 data)
1505{
1506 RING_IDX idx = vif->ctrl.rsp_prod_pvt;
1507 struct xen_netif_ctrl_response rsp = {
1508 .id = req->id,
1509 .type = req->type,
1510 .status = status,
1511 .data = data,
1512 };
1513
1514 *RING_GET_RESPONSE(&vif->ctrl, idx) = rsp;
1515 vif->ctrl.rsp_prod_pvt = ++idx;
1516}
1517
1518static void push_ctrl_response(struct xenvif *vif)
1519{
1520 int notify;
1521
1522 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->ctrl, notify);
1523 if (notify)
1524 notify_remote_via_irq(vif->ctrl_irq);
1525}
1526
1527static void process_ctrl_request(struct xenvif *vif,
1528 const struct xen_netif_ctrl_request *req)
1529{
1530 u32 status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED;
1531 u32 data = 0;
1532
1533 switch (req->type) {
1534 case XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM:
1535 status = xenvif_set_hash_alg(vif, req->data[0]);
1536 break;
1537
1538 case XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS:
1539 status = xenvif_get_hash_flags(vif, &data);
1540 break;
1541
1542 case XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS:
1543 status = xenvif_set_hash_flags(vif, req->data[0]);
1544 break;
1545
1546 case XEN_NETIF_CTRL_TYPE_SET_HASH_KEY:
1547 status = xenvif_set_hash_key(vif, req->data[0],
1548 req->data[1]);
1549 break;
1550
1551 case XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE:
1552 status = XEN_NETIF_CTRL_STATUS_SUCCESS;
1553 data = XEN_NETBK_MAX_HASH_MAPPING_SIZE;
1554 break;
1555
1556 case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE:
1557 status = xenvif_set_hash_mapping_size(vif,
1558 req->data[0]);
1559 break;
1560
1561 case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING:
1562 status = xenvif_set_hash_mapping(vif, req->data[0],
1563 req->data[1],
1564 req->data[2]);
1565 break;
1566
1567 default:
1568 break;
1569 }
1570
1571 make_ctrl_response(vif, req, status, data);
1572 push_ctrl_response(vif);
1573}
1574
1575static void xenvif_ctrl_action(struct xenvif *vif)
1576{
1577 for (;;) {
1578 RING_IDX req_prod, req_cons;
1579
1580 req_prod = vif->ctrl.sring->req_prod;
1581 req_cons = vif->ctrl.req_cons;
1582
1583 /* Make sure we can see requests before we process them. */
1584 rmb();
1585
1586 if (req_cons == req_prod)
1587 break;
1588
1589 while (req_cons != req_prod) {
1590 struct xen_netif_ctrl_request req;
1591
1592 RING_COPY_REQUEST(&vif->ctrl, req_cons, &req);
1593 req_cons++;
1594
1595 process_ctrl_request(vif, &req);
1596 }
1597
1598 vif->ctrl.req_cons = req_cons;
1599 vif->ctrl.sring->req_event = req_cons + 1;
1600 }
1601}
1602
1603static bool xenvif_ctrl_work_todo(struct xenvif *vif)
1604{
1605 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->ctrl)))
1606 return 1;
1607
1608 return 0;
1609}
1610
1611irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data)
1612{
1613 struct xenvif *vif = data;
1614
1615 while (xenvif_ctrl_work_todo(vif))
1616 xenvif_ctrl_action(vif);
1617
1618 return IRQ_HANDLED;
1619}
1620
1621static int __init netback_init(void)
1622{
1623 int rc = 0;
1624
1625 if (!xen_domain())
1626 return -ENODEV;
1627
1628 /* Allow as many queues as there are CPUs but max. 8 if user has not
1629 * specified a value.
1630 */
1631 if (xenvif_max_queues == 0)
1632 xenvif_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
1633 num_online_cpus());
1634
1635 if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
1636 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
1637 fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
1638 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
1639 }
1640
1641 rc = xenvif_xenbus_init();
1642 if (rc)
1643 goto failed_init;
1644
1645#ifdef CONFIG_DEBUG_FS
1646 xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
1647 if (IS_ERR_OR_NULL(xen_netback_dbg_root))
1648 pr_warn("Init of debugfs returned %ld!\n",
1649 PTR_ERR(xen_netback_dbg_root));
1650#endif /* CONFIG_DEBUG_FS */
1651
1652 return 0;
1653
1654failed_init:
1655 return rc;
1656}
1657
1658module_init(netback_init);
1659
1660static void __exit netback_fini(void)
1661{
1662#ifdef CONFIG_DEBUG_FS
1663 if (!IS_ERR_OR_NULL(xen_netback_dbg_root))
1664 debugfs_remove_recursive(xen_netback_dbg_root);
1665#endif /* CONFIG_DEBUG_FS */
1666 xenvif_xenbus_fini();
1667}
1668module_exit(netback_fini);
1669
1670MODULE_LICENSE("Dual BSD/GPL");
1671MODULE_ALIAS("xen-backend:vif");
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
41#include <net/tcp.h>
42
43#include <xen/events.h>
44#include <xen/interface/memory.h>
45
46#include <asm/xen/hypercall.h>
47#include <asm/xen/page.h>
48
49struct pending_tx_info {
50 struct xen_netif_tx_request req;
51 struct xenvif *vif;
52};
53typedef unsigned int pending_ring_idx_t;
54
55struct netbk_rx_meta {
56 int id;
57 int size;
58 int gso_size;
59};
60
61#define MAX_PENDING_REQS 256
62
63#define MAX_BUFFER_OFFSET PAGE_SIZE
64
65/* extra field used in struct page */
66union page_ext {
67 struct {
68#if BITS_PER_LONG < 64
69#define IDX_WIDTH 8
70#define GROUP_WIDTH (BITS_PER_LONG - IDX_WIDTH)
71 unsigned int group:GROUP_WIDTH;
72 unsigned int idx:IDX_WIDTH;
73#else
74 unsigned int group, idx;
75#endif
76 } e;
77 void *mapping;
78};
79
80struct xen_netbk {
81 wait_queue_head_t wq;
82 struct task_struct *task;
83
84 struct sk_buff_head rx_queue;
85 struct sk_buff_head tx_queue;
86
87 struct timer_list net_timer;
88
89 struct page *mmap_pages[MAX_PENDING_REQS];
90
91 pending_ring_idx_t pending_prod;
92 pending_ring_idx_t pending_cons;
93 struct list_head net_schedule_list;
94
95 /* Protect the net_schedule_list in netif. */
96 spinlock_t net_schedule_list_lock;
97
98 atomic_t netfront_count;
99
100 struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
101 struct gnttab_copy tx_copy_ops[MAX_PENDING_REQS];
102
103 u16 pending_ring[MAX_PENDING_REQS];
104
105 /*
106 * Given MAX_BUFFER_OFFSET of 4096 the worst case is that each
107 * head/fragment page uses 2 copy operations because it
108 * straddles two buffers in the frontend.
109 */
110 struct gnttab_copy grant_copy_op[2*XEN_NETIF_RX_RING_SIZE];
111 struct netbk_rx_meta meta[2*XEN_NETIF_RX_RING_SIZE];
112};
113
114static struct xen_netbk *xen_netbk;
115static int xen_netbk_group_nr;
116
117void xen_netbk_add_xenvif(struct xenvif *vif)
118{
119 int i;
120 int min_netfront_count;
121 int min_group = 0;
122 struct xen_netbk *netbk;
123
124 min_netfront_count = atomic_read(&xen_netbk[0].netfront_count);
125 for (i = 0; i < xen_netbk_group_nr; i++) {
126 int netfront_count = atomic_read(&xen_netbk[i].netfront_count);
127 if (netfront_count < min_netfront_count) {
128 min_group = i;
129 min_netfront_count = netfront_count;
130 }
131 }
132
133 netbk = &xen_netbk[min_group];
134
135 vif->netbk = netbk;
136 atomic_inc(&netbk->netfront_count);
137}
138
139void xen_netbk_remove_xenvif(struct xenvif *vif)
140{
141 struct xen_netbk *netbk = vif->netbk;
142 vif->netbk = NULL;
143 atomic_dec(&netbk->netfront_count);
144}
145
146static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx);
147static void make_tx_response(struct xenvif *vif,
148 struct xen_netif_tx_request *txp,
149 s8 st);
150static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
151 u16 id,
152 s8 st,
153 u16 offset,
154 u16 size,
155 u16 flags);
156
157static inline unsigned long idx_to_pfn(struct xen_netbk *netbk,
158 unsigned int idx)
159{
160 return page_to_pfn(netbk->mmap_pages[idx]);
161}
162
163static inline unsigned long idx_to_kaddr(struct xen_netbk *netbk,
164 unsigned int idx)
165{
166 return (unsigned long)pfn_to_kaddr(idx_to_pfn(netbk, idx));
167}
168
169/* extra field used in struct page */
170static inline void set_page_ext(struct page *pg, struct xen_netbk *netbk,
171 unsigned int idx)
172{
173 unsigned int group = netbk - xen_netbk;
174 union page_ext ext = { .e = { .group = group + 1, .idx = idx } };
175
176 BUILD_BUG_ON(sizeof(ext) > sizeof(ext.mapping));
177 pg->mapping = ext.mapping;
178}
179
180static int get_page_ext(struct page *pg,
181 unsigned int *pgroup, unsigned int *pidx)
182{
183 union page_ext ext = { .mapping = pg->mapping };
184 struct xen_netbk *netbk;
185 unsigned int group, idx;
186
187 group = ext.e.group - 1;
188
189 if (group < 0 || group >= xen_netbk_group_nr)
190 return 0;
191
192 netbk = &xen_netbk[group];
193
194 idx = ext.e.idx;
195
196 if ((idx < 0) || (idx >= MAX_PENDING_REQS))
197 return 0;
198
199 if (netbk->mmap_pages[idx] != pg)
200 return 0;
201
202 *pgroup = group;
203 *pidx = idx;
204
205 return 1;
206}
207
208/*
209 * This is the amount of packet we copy rather than map, so that the
210 * guest can't fiddle with the contents of the headers while we do
211 * packet processing on them (netfilter, routing, etc).
212 */
213#define PKT_PROT_LEN (ETH_HLEN + \
214 VLAN_HLEN + \
215 sizeof(struct iphdr) + MAX_IPOPTLEN + \
216 sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE)
217
218static inline pending_ring_idx_t pending_index(unsigned i)
219{
220 return i & (MAX_PENDING_REQS-1);
221}
222
223static inline pending_ring_idx_t nr_pending_reqs(struct xen_netbk *netbk)
224{
225 return MAX_PENDING_REQS -
226 netbk->pending_prod + netbk->pending_cons;
227}
228
229static void xen_netbk_kick_thread(struct xen_netbk *netbk)
230{
231 wake_up(&netbk->wq);
232}
233
234static int max_required_rx_slots(struct xenvif *vif)
235{
236 int max = DIV_ROUND_UP(vif->dev->mtu, PAGE_SIZE);
237
238 if (vif->can_sg || vif->gso || vif->gso_prefix)
239 max += MAX_SKB_FRAGS + 1; /* extra_info + frags */
240
241 return max;
242}
243
244int xen_netbk_rx_ring_full(struct xenvif *vif)
245{
246 RING_IDX peek = vif->rx_req_cons_peek;
247 RING_IDX needed = max_required_rx_slots(vif);
248
249 return ((vif->rx.sring->req_prod - peek) < needed) ||
250 ((vif->rx.rsp_prod_pvt + XEN_NETIF_RX_RING_SIZE - peek) < needed);
251}
252
253int xen_netbk_must_stop_queue(struct xenvif *vif)
254{
255 if (!xen_netbk_rx_ring_full(vif))
256 return 0;
257
258 vif->rx.sring->req_event = vif->rx_req_cons_peek +
259 max_required_rx_slots(vif);
260 mb(); /* request notification /then/ check the queue */
261
262 return xen_netbk_rx_ring_full(vif);
263}
264
265/*
266 * Returns true if we should start a new receive buffer instead of
267 * adding 'size' bytes to a buffer which currently contains 'offset'
268 * bytes.
269 */
270static bool start_new_rx_buffer(int offset, unsigned long size, int head)
271{
272 /* simple case: we have completely filled the current buffer. */
273 if (offset == MAX_BUFFER_OFFSET)
274 return true;
275
276 /*
277 * complex case: start a fresh buffer if the current frag
278 * would overflow the current buffer but only if:
279 * (i) this frag would fit completely in the next buffer
280 * and (ii) there is already some data in the current buffer
281 * and (iii) this is not the head buffer.
282 *
283 * Where:
284 * - (i) stops us splitting a frag into two copies
285 * unless the frag is too large for a single buffer.
286 * - (ii) stops us from leaving a buffer pointlessly empty.
287 * - (iii) stops us leaving the first buffer
288 * empty. Strictly speaking this is already covered
289 * by (ii) but is explicitly checked because
290 * netfront relies on the first buffer being
291 * non-empty and can crash otherwise.
292 *
293 * This means we will effectively linearise small
294 * frags but do not needlessly split large buffers
295 * into multiple copies tend to give large frags their
296 * own buffers as before.
297 */
298 if ((offset + size > MAX_BUFFER_OFFSET) &&
299 (size <= MAX_BUFFER_OFFSET) && offset && !head)
300 return true;
301
302 return false;
303}
304
305/*
306 * Figure out how many ring slots we're going to need to send @skb to
307 * the guest. This function is essentially a dry run of
308 * netbk_gop_frag_copy.
309 */
310unsigned int xen_netbk_count_skb_slots(struct xenvif *vif, struct sk_buff *skb)
311{
312 unsigned int count;
313 int i, copy_off;
314
315 count = DIV_ROUND_UP(
316 offset_in_page(skb->data)+skb_headlen(skb), PAGE_SIZE);
317
318 copy_off = skb_headlen(skb) % PAGE_SIZE;
319
320 if (skb_shinfo(skb)->gso_size)
321 count++;
322
323 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
324 unsigned long size = skb_shinfo(skb)->frags[i].size;
325 unsigned long bytes;
326 while (size > 0) {
327 BUG_ON(copy_off > MAX_BUFFER_OFFSET);
328
329 if (start_new_rx_buffer(copy_off, size, 0)) {
330 count++;
331 copy_off = 0;
332 }
333
334 bytes = size;
335 if (copy_off + bytes > MAX_BUFFER_OFFSET)
336 bytes = MAX_BUFFER_OFFSET - copy_off;
337
338 copy_off += bytes;
339 size -= bytes;
340 }
341 }
342 return count;
343}
344
345struct netrx_pending_operations {
346 unsigned copy_prod, copy_cons;
347 unsigned meta_prod, meta_cons;
348 struct gnttab_copy *copy;
349 struct netbk_rx_meta *meta;
350 int copy_off;
351 grant_ref_t copy_gref;
352};
353
354static struct netbk_rx_meta *get_next_rx_buffer(struct xenvif *vif,
355 struct netrx_pending_operations *npo)
356{
357 struct netbk_rx_meta *meta;
358 struct xen_netif_rx_request *req;
359
360 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
361
362 meta = npo->meta + npo->meta_prod++;
363 meta->gso_size = 0;
364 meta->size = 0;
365 meta->id = req->id;
366
367 npo->copy_off = 0;
368 npo->copy_gref = req->gref;
369
370 return meta;
371}
372
373/*
374 * Set up the grant operations for this fragment. If it's a flipping
375 * interface, we also set up the unmap request from here.
376 */
377static void netbk_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb,
378 struct netrx_pending_operations *npo,
379 struct page *page, unsigned long size,
380 unsigned long offset, int *head)
381{
382 struct gnttab_copy *copy_gop;
383 struct netbk_rx_meta *meta;
384 /*
385 * These variables a used iff get_page_ext returns true,
386 * in which case they are guaranteed to be initialized.
387 */
388 unsigned int uninitialized_var(group), uninitialized_var(idx);
389 int foreign = get_page_ext(page, &group, &idx);
390 unsigned long bytes;
391
392 /* Data must not cross a page boundary. */
393 BUG_ON(size + offset > PAGE_SIZE);
394
395 meta = npo->meta + npo->meta_prod - 1;
396
397 while (size > 0) {
398 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
399
400 if (start_new_rx_buffer(npo->copy_off, size, *head)) {
401 /*
402 * Netfront requires there to be some data in the head
403 * buffer.
404 */
405 BUG_ON(*head);
406
407 meta = get_next_rx_buffer(vif, npo);
408 }
409
410 bytes = size;
411 if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
412 bytes = MAX_BUFFER_OFFSET - npo->copy_off;
413
414 copy_gop = npo->copy + npo->copy_prod++;
415 copy_gop->flags = GNTCOPY_dest_gref;
416 if (foreign) {
417 struct xen_netbk *netbk = &xen_netbk[group];
418 struct pending_tx_info *src_pend;
419
420 src_pend = &netbk->pending_tx_info[idx];
421
422 copy_gop->source.domid = src_pend->vif->domid;
423 copy_gop->source.u.ref = src_pend->req.gref;
424 copy_gop->flags |= GNTCOPY_source_gref;
425 } else {
426 void *vaddr = page_address(page);
427 copy_gop->source.domid = DOMID_SELF;
428 copy_gop->source.u.gmfn = virt_to_mfn(vaddr);
429 }
430 copy_gop->source.offset = offset;
431 copy_gop->dest.domid = vif->domid;
432
433 copy_gop->dest.offset = npo->copy_off;
434 copy_gop->dest.u.ref = npo->copy_gref;
435 copy_gop->len = bytes;
436
437 npo->copy_off += bytes;
438 meta->size += bytes;
439
440 offset += bytes;
441 size -= bytes;
442
443 /* Leave a gap for the GSO descriptor. */
444 if (*head && skb_shinfo(skb)->gso_size && !vif->gso_prefix)
445 vif->rx.req_cons++;
446
447 *head = 0; /* There must be something in this buffer now. */
448
449 }
450}
451
452/*
453 * Prepare an SKB to be transmitted to the frontend.
454 *
455 * This function is responsible for allocating grant operations, meta
456 * structures, etc.
457 *
458 * It returns the number of meta structures consumed. The number of
459 * ring slots used is always equal to the number of meta slots used
460 * plus the number of GSO descriptors used. Currently, we use either
461 * zero GSO descriptors (for non-GSO packets) or one descriptor (for
462 * frontend-side LRO).
463 */
464static int netbk_gop_skb(struct sk_buff *skb,
465 struct netrx_pending_operations *npo)
466{
467 struct xenvif *vif = netdev_priv(skb->dev);
468 int nr_frags = skb_shinfo(skb)->nr_frags;
469 int i;
470 struct xen_netif_rx_request *req;
471 struct netbk_rx_meta *meta;
472 unsigned char *data;
473 int head = 1;
474 int old_meta_prod;
475
476 old_meta_prod = npo->meta_prod;
477
478 /* Set up a GSO prefix descriptor, if necessary */
479 if (skb_shinfo(skb)->gso_size && vif->gso_prefix) {
480 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
481 meta = npo->meta + npo->meta_prod++;
482 meta->gso_size = skb_shinfo(skb)->gso_size;
483 meta->size = 0;
484 meta->id = req->id;
485 }
486
487 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
488 meta = npo->meta + npo->meta_prod++;
489
490 if (!vif->gso_prefix)
491 meta->gso_size = skb_shinfo(skb)->gso_size;
492 else
493 meta->gso_size = 0;
494
495 meta->size = 0;
496 meta->id = req->id;
497 npo->copy_off = 0;
498 npo->copy_gref = req->gref;
499
500 data = skb->data;
501 while (data < skb_tail_pointer(skb)) {
502 unsigned int offset = offset_in_page(data);
503 unsigned int len = PAGE_SIZE - offset;
504
505 if (data + len > skb_tail_pointer(skb))
506 len = skb_tail_pointer(skb) - data;
507
508 netbk_gop_frag_copy(vif, skb, npo,
509 virt_to_page(data), len, offset, &head);
510 data += len;
511 }
512
513 for (i = 0; i < nr_frags; i++) {
514 netbk_gop_frag_copy(vif, skb, npo,
515 skb_shinfo(skb)->frags[i].page,
516 skb_shinfo(skb)->frags[i].size,
517 skb_shinfo(skb)->frags[i].page_offset,
518 &head);
519 }
520
521 return npo->meta_prod - old_meta_prod;
522}
523
524/*
525 * This is a twin to netbk_gop_skb. Assume that netbk_gop_skb was
526 * used to set up the operations on the top of
527 * netrx_pending_operations, which have since been done. Check that
528 * they didn't give any errors and advance over them.
529 */
530static int netbk_check_gop(struct xenvif *vif, int nr_meta_slots,
531 struct netrx_pending_operations *npo)
532{
533 struct gnttab_copy *copy_op;
534 int status = XEN_NETIF_RSP_OKAY;
535 int i;
536
537 for (i = 0; i < nr_meta_slots; i++) {
538 copy_op = npo->copy + npo->copy_cons++;
539 if (copy_op->status != GNTST_okay) {
540 netdev_dbg(vif->dev,
541 "Bad status %d from copy to DOM%d.\n",
542 copy_op->status, vif->domid);
543 status = XEN_NETIF_RSP_ERROR;
544 }
545 }
546
547 return status;
548}
549
550static void netbk_add_frag_responses(struct xenvif *vif, int status,
551 struct netbk_rx_meta *meta,
552 int nr_meta_slots)
553{
554 int i;
555 unsigned long offset;
556
557 /* No fragments used */
558 if (nr_meta_slots <= 1)
559 return;
560
561 nr_meta_slots--;
562
563 for (i = 0; i < nr_meta_slots; i++) {
564 int flags;
565 if (i == nr_meta_slots - 1)
566 flags = 0;
567 else
568 flags = XEN_NETRXF_more_data;
569
570 offset = 0;
571 make_rx_response(vif, meta[i].id, status, offset,
572 meta[i].size, flags);
573 }
574}
575
576struct skb_cb_overlay {
577 int meta_slots_used;
578};
579
580static void xen_netbk_rx_action(struct xen_netbk *netbk)
581{
582 struct xenvif *vif = NULL, *tmp;
583 s8 status;
584 u16 irq, flags;
585 struct xen_netif_rx_response *resp;
586 struct sk_buff_head rxq;
587 struct sk_buff *skb;
588 LIST_HEAD(notify);
589 int ret;
590 int nr_frags;
591 int count;
592 unsigned long offset;
593 struct skb_cb_overlay *sco;
594
595 struct netrx_pending_operations npo = {
596 .copy = netbk->grant_copy_op,
597 .meta = netbk->meta,
598 };
599
600 skb_queue_head_init(&rxq);
601
602 count = 0;
603
604 while ((skb = skb_dequeue(&netbk->rx_queue)) != NULL) {
605 vif = netdev_priv(skb->dev);
606 nr_frags = skb_shinfo(skb)->nr_frags;
607
608 sco = (struct skb_cb_overlay *)skb->cb;
609 sco->meta_slots_used = netbk_gop_skb(skb, &npo);
610
611 count += nr_frags + 1;
612
613 __skb_queue_tail(&rxq, skb);
614
615 /* Filled the batch queue? */
616 if (count + MAX_SKB_FRAGS >= XEN_NETIF_RX_RING_SIZE)
617 break;
618 }
619
620 BUG_ON(npo.meta_prod > ARRAY_SIZE(netbk->meta));
621
622 if (!npo.copy_prod)
623 return;
624
625 BUG_ON(npo.copy_prod > ARRAY_SIZE(netbk->grant_copy_op));
626 ret = HYPERVISOR_grant_table_op(GNTTABOP_copy, &netbk->grant_copy_op,
627 npo.copy_prod);
628 BUG_ON(ret != 0);
629
630 while ((skb = __skb_dequeue(&rxq)) != NULL) {
631 sco = (struct skb_cb_overlay *)skb->cb;
632
633 vif = netdev_priv(skb->dev);
634
635 if (netbk->meta[npo.meta_cons].gso_size && vif->gso_prefix) {
636 resp = RING_GET_RESPONSE(&vif->rx,
637 vif->rx.rsp_prod_pvt++);
638
639 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
640
641 resp->offset = netbk->meta[npo.meta_cons].gso_size;
642 resp->id = netbk->meta[npo.meta_cons].id;
643 resp->status = sco->meta_slots_used;
644
645 npo.meta_cons++;
646 sco->meta_slots_used--;
647 }
648
649
650 vif->dev->stats.tx_bytes += skb->len;
651 vif->dev->stats.tx_packets++;
652
653 status = netbk_check_gop(vif, sco->meta_slots_used, &npo);
654
655 if (sco->meta_slots_used == 1)
656 flags = 0;
657 else
658 flags = XEN_NETRXF_more_data;
659
660 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
661 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
662 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
663 /* remote but checksummed. */
664 flags |= XEN_NETRXF_data_validated;
665
666 offset = 0;
667 resp = make_rx_response(vif, netbk->meta[npo.meta_cons].id,
668 status, offset,
669 netbk->meta[npo.meta_cons].size,
670 flags);
671
672 if (netbk->meta[npo.meta_cons].gso_size && !vif->gso_prefix) {
673 struct xen_netif_extra_info *gso =
674 (struct xen_netif_extra_info *)
675 RING_GET_RESPONSE(&vif->rx,
676 vif->rx.rsp_prod_pvt++);
677
678 resp->flags |= XEN_NETRXF_extra_info;
679
680 gso->u.gso.size = netbk->meta[npo.meta_cons].gso_size;
681 gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
682 gso->u.gso.pad = 0;
683 gso->u.gso.features = 0;
684
685 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
686 gso->flags = 0;
687 }
688
689 netbk_add_frag_responses(vif, status,
690 netbk->meta + npo.meta_cons + 1,
691 sco->meta_slots_used);
692
693 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret);
694 irq = vif->irq;
695 if (ret && list_empty(&vif->notify_list))
696 list_add_tail(&vif->notify_list, ¬ify);
697
698 xenvif_notify_tx_completion(vif);
699
700 xenvif_put(vif);
701 npo.meta_cons += sco->meta_slots_used;
702 dev_kfree_skb(skb);
703 }
704
705 list_for_each_entry_safe(vif, tmp, ¬ify, notify_list) {
706 notify_remote_via_irq(vif->irq);
707 list_del_init(&vif->notify_list);
708 }
709
710 /* More work to do? */
711 if (!skb_queue_empty(&netbk->rx_queue) &&
712 !timer_pending(&netbk->net_timer))
713 xen_netbk_kick_thread(netbk);
714}
715
716void xen_netbk_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb)
717{
718 struct xen_netbk *netbk = vif->netbk;
719
720 skb_queue_tail(&netbk->rx_queue, skb);
721
722 xen_netbk_kick_thread(netbk);
723}
724
725static void xen_netbk_alarm(unsigned long data)
726{
727 struct xen_netbk *netbk = (struct xen_netbk *)data;
728 xen_netbk_kick_thread(netbk);
729}
730
731static int __on_net_schedule_list(struct xenvif *vif)
732{
733 return !list_empty(&vif->schedule_list);
734}
735
736/* Must be called with net_schedule_list_lock held */
737static void remove_from_net_schedule_list(struct xenvif *vif)
738{
739 if (likely(__on_net_schedule_list(vif))) {
740 list_del_init(&vif->schedule_list);
741 xenvif_put(vif);
742 }
743}
744
745static struct xenvif *poll_net_schedule_list(struct xen_netbk *netbk)
746{
747 struct xenvif *vif = NULL;
748
749 spin_lock_irq(&netbk->net_schedule_list_lock);
750 if (list_empty(&netbk->net_schedule_list))
751 goto out;
752
753 vif = list_first_entry(&netbk->net_schedule_list,
754 struct xenvif, schedule_list);
755 if (!vif)
756 goto out;
757
758 xenvif_get(vif);
759
760 remove_from_net_schedule_list(vif);
761out:
762 spin_unlock_irq(&netbk->net_schedule_list_lock);
763 return vif;
764}
765
766void xen_netbk_schedule_xenvif(struct xenvif *vif)
767{
768 unsigned long flags;
769 struct xen_netbk *netbk = vif->netbk;
770
771 if (__on_net_schedule_list(vif))
772 goto kick;
773
774 spin_lock_irqsave(&netbk->net_schedule_list_lock, flags);
775 if (!__on_net_schedule_list(vif) &&
776 likely(xenvif_schedulable(vif))) {
777 list_add_tail(&vif->schedule_list, &netbk->net_schedule_list);
778 xenvif_get(vif);
779 }
780 spin_unlock_irqrestore(&netbk->net_schedule_list_lock, flags);
781
782kick:
783 smp_mb();
784 if ((nr_pending_reqs(netbk) < (MAX_PENDING_REQS/2)) &&
785 !list_empty(&netbk->net_schedule_list))
786 xen_netbk_kick_thread(netbk);
787}
788
789void xen_netbk_deschedule_xenvif(struct xenvif *vif)
790{
791 struct xen_netbk *netbk = vif->netbk;
792 spin_lock_irq(&netbk->net_schedule_list_lock);
793 remove_from_net_schedule_list(vif);
794 spin_unlock_irq(&netbk->net_schedule_list_lock);
795}
796
797void xen_netbk_check_rx_xenvif(struct xenvif *vif)
798{
799 int more_to_do;
800
801 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
802
803 if (more_to_do)
804 xen_netbk_schedule_xenvif(vif);
805}
806
807static void tx_add_credit(struct xenvif *vif)
808{
809 unsigned long max_burst, max_credit;
810
811 /*
812 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
813 * Otherwise the interface can seize up due to insufficient credit.
814 */
815 max_burst = RING_GET_REQUEST(&vif->tx, vif->tx.req_cons)->size;
816 max_burst = min(max_burst, 131072UL);
817 max_burst = max(max_burst, vif->credit_bytes);
818
819 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
820 max_credit = vif->remaining_credit + vif->credit_bytes;
821 if (max_credit < vif->remaining_credit)
822 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
823
824 vif->remaining_credit = min(max_credit, max_burst);
825}
826
827static void tx_credit_callback(unsigned long data)
828{
829 struct xenvif *vif = (struct xenvif *)data;
830 tx_add_credit(vif);
831 xen_netbk_check_rx_xenvif(vif);
832}
833
834static void netbk_tx_err(struct xenvif *vif,
835 struct xen_netif_tx_request *txp, RING_IDX end)
836{
837 RING_IDX cons = vif->tx.req_cons;
838
839 do {
840 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
841 if (cons >= end)
842 break;
843 txp = RING_GET_REQUEST(&vif->tx, cons++);
844 } while (1);
845 vif->tx.req_cons = cons;
846 xen_netbk_check_rx_xenvif(vif);
847 xenvif_put(vif);
848}
849
850static int netbk_count_requests(struct xenvif *vif,
851 struct xen_netif_tx_request *first,
852 struct xen_netif_tx_request *txp,
853 int work_to_do)
854{
855 RING_IDX cons = vif->tx.req_cons;
856 int frags = 0;
857
858 if (!(first->flags & XEN_NETTXF_more_data))
859 return 0;
860
861 do {
862 if (frags >= work_to_do) {
863 netdev_dbg(vif->dev, "Need more frags\n");
864 return -frags;
865 }
866
867 if (unlikely(frags >= MAX_SKB_FRAGS)) {
868 netdev_dbg(vif->dev, "Too many frags\n");
869 return -frags;
870 }
871
872 memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + frags),
873 sizeof(*txp));
874 if (txp->size > first->size) {
875 netdev_dbg(vif->dev, "Frags galore\n");
876 return -frags;
877 }
878
879 first->size -= txp->size;
880 frags++;
881
882 if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
883 netdev_dbg(vif->dev, "txp->offset: %x, size: %u\n",
884 txp->offset, txp->size);
885 return -frags;
886 }
887 } while ((txp++)->flags & XEN_NETTXF_more_data);
888 return frags;
889}
890
891static struct page *xen_netbk_alloc_page(struct xen_netbk *netbk,
892 struct sk_buff *skb,
893 unsigned long pending_idx)
894{
895 struct page *page;
896 page = alloc_page(GFP_KERNEL|__GFP_COLD);
897 if (!page)
898 return NULL;
899 set_page_ext(page, netbk, pending_idx);
900 netbk->mmap_pages[pending_idx] = page;
901 return page;
902}
903
904static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
905 struct xenvif *vif,
906 struct sk_buff *skb,
907 struct xen_netif_tx_request *txp,
908 struct gnttab_copy *gop)
909{
910 struct skb_shared_info *shinfo = skb_shinfo(skb);
911 skb_frag_t *frags = shinfo->frags;
912 unsigned long pending_idx = *((u16 *)skb->data);
913 int i, start;
914
915 /* Skip first skb fragment if it is on same page as header fragment. */
916 start = ((unsigned long)shinfo->frags[0].page == pending_idx);
917
918 for (i = start; i < shinfo->nr_frags; i++, txp++) {
919 struct page *page;
920 pending_ring_idx_t index;
921 struct pending_tx_info *pending_tx_info =
922 netbk->pending_tx_info;
923
924 index = pending_index(netbk->pending_cons++);
925 pending_idx = netbk->pending_ring[index];
926 page = xen_netbk_alloc_page(netbk, skb, pending_idx);
927 if (!page)
928 return NULL;
929
930 netbk->mmap_pages[pending_idx] = page;
931
932 gop->source.u.ref = txp->gref;
933 gop->source.domid = vif->domid;
934 gop->source.offset = txp->offset;
935
936 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
937 gop->dest.domid = DOMID_SELF;
938 gop->dest.offset = txp->offset;
939
940 gop->len = txp->size;
941 gop->flags = GNTCOPY_source_gref;
942
943 gop++;
944
945 memcpy(&pending_tx_info[pending_idx].req, txp, sizeof(*txp));
946 xenvif_get(vif);
947 pending_tx_info[pending_idx].vif = vif;
948 frags[i].page = (void *)pending_idx;
949 }
950
951 return gop;
952}
953
954static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
955 struct sk_buff *skb,
956 struct gnttab_copy **gopp)
957{
958 struct gnttab_copy *gop = *gopp;
959 int pending_idx = *((u16 *)skb->data);
960 struct pending_tx_info *pending_tx_info = netbk->pending_tx_info;
961 struct xenvif *vif = pending_tx_info[pending_idx].vif;
962 struct xen_netif_tx_request *txp;
963 struct skb_shared_info *shinfo = skb_shinfo(skb);
964 int nr_frags = shinfo->nr_frags;
965 int i, err, start;
966
967 /* Check status of header. */
968 err = gop->status;
969 if (unlikely(err)) {
970 pending_ring_idx_t index;
971 index = pending_index(netbk->pending_prod++);
972 txp = &pending_tx_info[pending_idx].req;
973 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
974 netbk->pending_ring[index] = pending_idx;
975 xenvif_put(vif);
976 }
977
978 /* Skip first skb fragment if it is on same page as header fragment. */
979 start = ((unsigned long)shinfo->frags[0].page == pending_idx);
980
981 for (i = start; i < nr_frags; i++) {
982 int j, newerr;
983 pending_ring_idx_t index;
984
985 pending_idx = (unsigned long)shinfo->frags[i].page;
986
987 /* Check error status: if okay then remember grant handle. */
988 newerr = (++gop)->status;
989 if (likely(!newerr)) {
990 /* Had a previous error? Invalidate this fragment. */
991 if (unlikely(err))
992 xen_netbk_idx_release(netbk, pending_idx);
993 continue;
994 }
995
996 /* Error on this fragment: respond to client with an error. */
997 txp = &netbk->pending_tx_info[pending_idx].req;
998 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
999 index = pending_index(netbk->pending_prod++);
1000 netbk->pending_ring[index] = pending_idx;
1001 xenvif_put(vif);
1002
1003 /* Not the first error? Preceding frags already invalidated. */
1004 if (err)
1005 continue;
1006
1007 /* First error: invalidate header and preceding fragments. */
1008 pending_idx = *((u16 *)skb->data);
1009 xen_netbk_idx_release(netbk, pending_idx);
1010 for (j = start; j < i; j++) {
1011 pending_idx = (unsigned long)shinfo->frags[i].page;
1012 xen_netbk_idx_release(netbk, pending_idx);
1013 }
1014
1015 /* Remember the error: invalidate all subsequent fragments. */
1016 err = newerr;
1017 }
1018
1019 *gopp = gop + 1;
1020 return err;
1021}
1022
1023static void xen_netbk_fill_frags(struct xen_netbk *netbk, struct sk_buff *skb)
1024{
1025 struct skb_shared_info *shinfo = skb_shinfo(skb);
1026 int nr_frags = shinfo->nr_frags;
1027 int i;
1028
1029 for (i = 0; i < nr_frags; i++) {
1030 skb_frag_t *frag = shinfo->frags + i;
1031 struct xen_netif_tx_request *txp;
1032 unsigned long pending_idx;
1033
1034 pending_idx = (unsigned long)frag->page;
1035
1036 txp = &netbk->pending_tx_info[pending_idx].req;
1037 frag->page = virt_to_page(idx_to_kaddr(netbk, pending_idx));
1038 frag->size = txp->size;
1039 frag->page_offset = txp->offset;
1040
1041 skb->len += txp->size;
1042 skb->data_len += txp->size;
1043 skb->truesize += txp->size;
1044
1045 /* Take an extra reference to offset xen_netbk_idx_release */
1046 get_page(netbk->mmap_pages[pending_idx]);
1047 xen_netbk_idx_release(netbk, pending_idx);
1048 }
1049}
1050
1051static int xen_netbk_get_extras(struct xenvif *vif,
1052 struct xen_netif_extra_info *extras,
1053 int work_to_do)
1054{
1055 struct xen_netif_extra_info extra;
1056 RING_IDX cons = vif->tx.req_cons;
1057
1058 do {
1059 if (unlikely(work_to_do-- <= 0)) {
1060 netdev_dbg(vif->dev, "Missing extra info\n");
1061 return -EBADR;
1062 }
1063
1064 memcpy(&extra, RING_GET_REQUEST(&vif->tx, cons),
1065 sizeof(extra));
1066 if (unlikely(!extra.type ||
1067 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1068 vif->tx.req_cons = ++cons;
1069 netdev_dbg(vif->dev,
1070 "Invalid extra type: %d\n", extra.type);
1071 return -EINVAL;
1072 }
1073
1074 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1075 vif->tx.req_cons = ++cons;
1076 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1077
1078 return work_to_do;
1079}
1080
1081static int netbk_set_skb_gso(struct xenvif *vif,
1082 struct sk_buff *skb,
1083 struct xen_netif_extra_info *gso)
1084{
1085 if (!gso->u.gso.size) {
1086 netdev_dbg(vif->dev, "GSO size must not be zero.\n");
1087 return -EINVAL;
1088 }
1089
1090 /* Currently only TCPv4 S.O. is supported. */
1091 if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
1092 netdev_dbg(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1093 return -EINVAL;
1094 }
1095
1096 skb_shinfo(skb)->gso_size = gso->u.gso.size;
1097 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1098
1099 /* Header must be checked, and gso_segs computed. */
1100 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1101 skb_shinfo(skb)->gso_segs = 0;
1102
1103 return 0;
1104}
1105
1106static int checksum_setup(struct xenvif *vif, struct sk_buff *skb)
1107{
1108 struct iphdr *iph;
1109 unsigned char *th;
1110 int err = -EPROTO;
1111 int recalculate_partial_csum = 0;
1112
1113 /*
1114 * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1115 * peers can fail to set NETRXF_csum_blank when sending a GSO
1116 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1117 * recalculate the partial checksum.
1118 */
1119 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1120 vif->rx_gso_checksum_fixup++;
1121 skb->ip_summed = CHECKSUM_PARTIAL;
1122 recalculate_partial_csum = 1;
1123 }
1124
1125 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1126 if (skb->ip_summed != CHECKSUM_PARTIAL)
1127 return 0;
1128
1129 if (skb->protocol != htons(ETH_P_IP))
1130 goto out;
1131
1132 iph = (void *)skb->data;
1133 th = skb->data + 4 * iph->ihl;
1134 if (th >= skb_tail_pointer(skb))
1135 goto out;
1136
1137 skb->csum_start = th - skb->head;
1138 switch (iph->protocol) {
1139 case IPPROTO_TCP:
1140 skb->csum_offset = offsetof(struct tcphdr, check);
1141
1142 if (recalculate_partial_csum) {
1143 struct tcphdr *tcph = (struct tcphdr *)th;
1144 tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1145 skb->len - iph->ihl*4,
1146 IPPROTO_TCP, 0);
1147 }
1148 break;
1149 case IPPROTO_UDP:
1150 skb->csum_offset = offsetof(struct udphdr, check);
1151
1152 if (recalculate_partial_csum) {
1153 struct udphdr *udph = (struct udphdr *)th;
1154 udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1155 skb->len - iph->ihl*4,
1156 IPPROTO_UDP, 0);
1157 }
1158 break;
1159 default:
1160 if (net_ratelimit())
1161 netdev_err(vif->dev,
1162 "Attempting to checksum a non-TCP/UDP packet, dropping a protocol %d packet\n",
1163 iph->protocol);
1164 goto out;
1165 }
1166
1167 if ((th + skb->csum_offset + 2) > skb_tail_pointer(skb))
1168 goto out;
1169
1170 err = 0;
1171
1172out:
1173 return err;
1174}
1175
1176static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
1177{
1178 unsigned long now = jiffies;
1179 unsigned long next_credit =
1180 vif->credit_timeout.expires +
1181 msecs_to_jiffies(vif->credit_usec / 1000);
1182
1183 /* Timer could already be pending in rare cases. */
1184 if (timer_pending(&vif->credit_timeout))
1185 return true;
1186
1187 /* Passed the point where we can replenish credit? */
1188 if (time_after_eq(now, next_credit)) {
1189 vif->credit_timeout.expires = now;
1190 tx_add_credit(vif);
1191 }
1192
1193 /* Still too big to send right now? Set a callback. */
1194 if (size > vif->remaining_credit) {
1195 vif->credit_timeout.data =
1196 (unsigned long)vif;
1197 vif->credit_timeout.function =
1198 tx_credit_callback;
1199 mod_timer(&vif->credit_timeout,
1200 next_credit);
1201
1202 return true;
1203 }
1204
1205 return false;
1206}
1207
1208static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk)
1209{
1210 struct gnttab_copy *gop = netbk->tx_copy_ops, *request_gop;
1211 struct sk_buff *skb;
1212 int ret;
1213
1214 while (((nr_pending_reqs(netbk) + MAX_SKB_FRAGS) < MAX_PENDING_REQS) &&
1215 !list_empty(&netbk->net_schedule_list)) {
1216 struct xenvif *vif;
1217 struct xen_netif_tx_request txreq;
1218 struct xen_netif_tx_request txfrags[MAX_SKB_FRAGS];
1219 struct page *page;
1220 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
1221 u16 pending_idx;
1222 RING_IDX idx;
1223 int work_to_do;
1224 unsigned int data_len;
1225 pending_ring_idx_t index;
1226
1227 /* Get a netif from the list with work to do. */
1228 vif = poll_net_schedule_list(netbk);
1229 if (!vif)
1230 continue;
1231
1232 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, work_to_do);
1233 if (!work_to_do) {
1234 xenvif_put(vif);
1235 continue;
1236 }
1237
1238 idx = vif->tx.req_cons;
1239 rmb(); /* Ensure that we see the request before we copy it. */
1240 memcpy(&txreq, RING_GET_REQUEST(&vif->tx, idx), sizeof(txreq));
1241
1242 /* Credit-based scheduling. */
1243 if (txreq.size > vif->remaining_credit &&
1244 tx_credit_exceeded(vif, txreq.size)) {
1245 xenvif_put(vif);
1246 continue;
1247 }
1248
1249 vif->remaining_credit -= txreq.size;
1250
1251 work_to_do--;
1252 vif->tx.req_cons = ++idx;
1253
1254 memset(extras, 0, sizeof(extras));
1255 if (txreq.flags & XEN_NETTXF_extra_info) {
1256 work_to_do = xen_netbk_get_extras(vif, extras,
1257 work_to_do);
1258 idx = vif->tx.req_cons;
1259 if (unlikely(work_to_do < 0)) {
1260 netbk_tx_err(vif, &txreq, idx);
1261 continue;
1262 }
1263 }
1264
1265 ret = netbk_count_requests(vif, &txreq, txfrags, work_to_do);
1266 if (unlikely(ret < 0)) {
1267 netbk_tx_err(vif, &txreq, idx - ret);
1268 continue;
1269 }
1270 idx += ret;
1271
1272 if (unlikely(txreq.size < ETH_HLEN)) {
1273 netdev_dbg(vif->dev,
1274 "Bad packet size: %d\n", txreq.size);
1275 netbk_tx_err(vif, &txreq, idx);
1276 continue;
1277 }
1278
1279 /* No crossing a page as the payload mustn't fragment. */
1280 if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
1281 netdev_dbg(vif->dev,
1282 "txreq.offset: %x, size: %u, end: %lu\n",
1283 txreq.offset, txreq.size,
1284 (txreq.offset&~PAGE_MASK) + txreq.size);
1285 netbk_tx_err(vif, &txreq, idx);
1286 continue;
1287 }
1288
1289 index = pending_index(netbk->pending_cons);
1290 pending_idx = netbk->pending_ring[index];
1291
1292 data_len = (txreq.size > PKT_PROT_LEN &&
1293 ret < MAX_SKB_FRAGS) ?
1294 PKT_PROT_LEN : txreq.size;
1295
1296 skb = alloc_skb(data_len + NET_SKB_PAD + NET_IP_ALIGN,
1297 GFP_ATOMIC | __GFP_NOWARN);
1298 if (unlikely(skb == NULL)) {
1299 netdev_dbg(vif->dev,
1300 "Can't allocate a skb in start_xmit.\n");
1301 netbk_tx_err(vif, &txreq, idx);
1302 break;
1303 }
1304
1305 /* Packets passed to netif_rx() must have some headroom. */
1306 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
1307
1308 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1309 struct xen_netif_extra_info *gso;
1310 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1311
1312 if (netbk_set_skb_gso(vif, skb, gso)) {
1313 kfree_skb(skb);
1314 netbk_tx_err(vif, &txreq, idx);
1315 continue;
1316 }
1317 }
1318
1319 /* XXX could copy straight to head */
1320 page = xen_netbk_alloc_page(netbk, skb, pending_idx);
1321 if (!page) {
1322 kfree_skb(skb);
1323 netbk_tx_err(vif, &txreq, idx);
1324 continue;
1325 }
1326
1327 netbk->mmap_pages[pending_idx] = page;
1328
1329 gop->source.u.ref = txreq.gref;
1330 gop->source.domid = vif->domid;
1331 gop->source.offset = txreq.offset;
1332
1333 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
1334 gop->dest.domid = DOMID_SELF;
1335 gop->dest.offset = txreq.offset;
1336
1337 gop->len = txreq.size;
1338 gop->flags = GNTCOPY_source_gref;
1339
1340 gop++;
1341
1342 memcpy(&netbk->pending_tx_info[pending_idx].req,
1343 &txreq, sizeof(txreq));
1344 netbk->pending_tx_info[pending_idx].vif = vif;
1345 *((u16 *)skb->data) = pending_idx;
1346
1347 __skb_put(skb, data_len);
1348
1349 skb_shinfo(skb)->nr_frags = ret;
1350 if (data_len < txreq.size) {
1351 skb_shinfo(skb)->nr_frags++;
1352 skb_shinfo(skb)->frags[0].page =
1353 (void *)(unsigned long)pending_idx;
1354 } else {
1355 /* Discriminate from any valid pending_idx value. */
1356 skb_shinfo(skb)->frags[0].page = (void *)~0UL;
1357 }
1358
1359 __skb_queue_tail(&netbk->tx_queue, skb);
1360
1361 netbk->pending_cons++;
1362
1363 request_gop = xen_netbk_get_requests(netbk, vif,
1364 skb, txfrags, gop);
1365 if (request_gop == NULL) {
1366 kfree_skb(skb);
1367 netbk_tx_err(vif, &txreq, idx);
1368 continue;
1369 }
1370 gop = request_gop;
1371
1372 vif->tx.req_cons = idx;
1373 xen_netbk_check_rx_xenvif(vif);
1374
1375 if ((gop-netbk->tx_copy_ops) >= ARRAY_SIZE(netbk->tx_copy_ops))
1376 break;
1377 }
1378
1379 return gop - netbk->tx_copy_ops;
1380}
1381
1382static void xen_netbk_tx_submit(struct xen_netbk *netbk)
1383{
1384 struct gnttab_copy *gop = netbk->tx_copy_ops;
1385 struct sk_buff *skb;
1386
1387 while ((skb = __skb_dequeue(&netbk->tx_queue)) != NULL) {
1388 struct xen_netif_tx_request *txp;
1389 struct xenvif *vif;
1390 u16 pending_idx;
1391 unsigned data_len;
1392
1393 pending_idx = *((u16 *)skb->data);
1394 vif = netbk->pending_tx_info[pending_idx].vif;
1395 txp = &netbk->pending_tx_info[pending_idx].req;
1396
1397 /* Check the remap error code. */
1398 if (unlikely(xen_netbk_tx_check_gop(netbk, skb, &gop))) {
1399 netdev_dbg(vif->dev, "netback grant failed.\n");
1400 skb_shinfo(skb)->nr_frags = 0;
1401 kfree_skb(skb);
1402 continue;
1403 }
1404
1405 data_len = skb->len;
1406 memcpy(skb->data,
1407 (void *)(idx_to_kaddr(netbk, pending_idx)|txp->offset),
1408 data_len);
1409 if (data_len < txp->size) {
1410 /* Append the packet payload as a fragment. */
1411 txp->offset += data_len;
1412 txp->size -= data_len;
1413 } else {
1414 /* Schedule a response immediately. */
1415 xen_netbk_idx_release(netbk, pending_idx);
1416 }
1417
1418 if (txp->flags & XEN_NETTXF_csum_blank)
1419 skb->ip_summed = CHECKSUM_PARTIAL;
1420 else if (txp->flags & XEN_NETTXF_data_validated)
1421 skb->ip_summed = CHECKSUM_UNNECESSARY;
1422
1423 xen_netbk_fill_frags(netbk, skb);
1424
1425 /*
1426 * If the initial fragment was < PKT_PROT_LEN then
1427 * pull through some bytes from the other fragments to
1428 * increase the linear region to PKT_PROT_LEN bytes.
1429 */
1430 if (skb_headlen(skb) < PKT_PROT_LEN && skb_is_nonlinear(skb)) {
1431 int target = min_t(int, skb->len, PKT_PROT_LEN);
1432 __pskb_pull_tail(skb, target - skb_headlen(skb));
1433 }
1434
1435 skb->dev = vif->dev;
1436 skb->protocol = eth_type_trans(skb, skb->dev);
1437
1438 if (checksum_setup(vif, skb)) {
1439 netdev_dbg(vif->dev,
1440 "Can't setup checksum in net_tx_action\n");
1441 kfree_skb(skb);
1442 continue;
1443 }
1444
1445 vif->dev->stats.rx_bytes += skb->len;
1446 vif->dev->stats.rx_packets++;
1447
1448 xenvif_receive_skb(vif, skb);
1449 }
1450}
1451
1452/* Called after netfront has transmitted */
1453static void xen_netbk_tx_action(struct xen_netbk *netbk)
1454{
1455 unsigned nr_gops;
1456 int ret;
1457
1458 nr_gops = xen_netbk_tx_build_gops(netbk);
1459
1460 if (nr_gops == 0)
1461 return;
1462 ret = HYPERVISOR_grant_table_op(GNTTABOP_copy,
1463 netbk->tx_copy_ops, nr_gops);
1464 BUG_ON(ret);
1465
1466 xen_netbk_tx_submit(netbk);
1467
1468}
1469
1470static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx)
1471{
1472 struct xenvif *vif;
1473 struct pending_tx_info *pending_tx_info;
1474 pending_ring_idx_t index;
1475
1476 /* Already complete? */
1477 if (netbk->mmap_pages[pending_idx] == NULL)
1478 return;
1479
1480 pending_tx_info = &netbk->pending_tx_info[pending_idx];
1481
1482 vif = pending_tx_info->vif;
1483
1484 make_tx_response(vif, &pending_tx_info->req, XEN_NETIF_RSP_OKAY);
1485
1486 index = pending_index(netbk->pending_prod++);
1487 netbk->pending_ring[index] = pending_idx;
1488
1489 xenvif_put(vif);
1490
1491 netbk->mmap_pages[pending_idx]->mapping = 0;
1492 put_page(netbk->mmap_pages[pending_idx]);
1493 netbk->mmap_pages[pending_idx] = NULL;
1494}
1495
1496static void make_tx_response(struct xenvif *vif,
1497 struct xen_netif_tx_request *txp,
1498 s8 st)
1499{
1500 RING_IDX i = vif->tx.rsp_prod_pvt;
1501 struct xen_netif_tx_response *resp;
1502 int notify;
1503
1504 resp = RING_GET_RESPONSE(&vif->tx, i);
1505 resp->id = txp->id;
1506 resp->status = st;
1507
1508 if (txp->flags & XEN_NETTXF_extra_info)
1509 RING_GET_RESPONSE(&vif->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1510
1511 vif->tx.rsp_prod_pvt = ++i;
1512 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->tx, notify);
1513 if (notify)
1514 notify_remote_via_irq(vif->irq);
1515}
1516
1517static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
1518 u16 id,
1519 s8 st,
1520 u16 offset,
1521 u16 size,
1522 u16 flags)
1523{
1524 RING_IDX i = vif->rx.rsp_prod_pvt;
1525 struct xen_netif_rx_response *resp;
1526
1527 resp = RING_GET_RESPONSE(&vif->rx, i);
1528 resp->offset = offset;
1529 resp->flags = flags;
1530 resp->id = id;
1531 resp->status = (s16)size;
1532 if (st < 0)
1533 resp->status = (s16)st;
1534
1535 vif->rx.rsp_prod_pvt = ++i;
1536
1537 return resp;
1538}
1539
1540static inline int rx_work_todo(struct xen_netbk *netbk)
1541{
1542 return !skb_queue_empty(&netbk->rx_queue);
1543}
1544
1545static inline int tx_work_todo(struct xen_netbk *netbk)
1546{
1547
1548 if (((nr_pending_reqs(netbk) + MAX_SKB_FRAGS) < MAX_PENDING_REQS) &&
1549 !list_empty(&netbk->net_schedule_list))
1550 return 1;
1551
1552 return 0;
1553}
1554
1555static int xen_netbk_kthread(void *data)
1556{
1557 struct xen_netbk *netbk = data;
1558 while (!kthread_should_stop()) {
1559 wait_event_interruptible(netbk->wq,
1560 rx_work_todo(netbk) ||
1561 tx_work_todo(netbk) ||
1562 kthread_should_stop());
1563 cond_resched();
1564
1565 if (kthread_should_stop())
1566 break;
1567
1568 if (rx_work_todo(netbk))
1569 xen_netbk_rx_action(netbk);
1570
1571 if (tx_work_todo(netbk))
1572 xen_netbk_tx_action(netbk);
1573 }
1574
1575 return 0;
1576}
1577
1578void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
1579{
1580 struct gnttab_unmap_grant_ref op;
1581
1582 if (vif->tx.sring) {
1583 gnttab_set_unmap_op(&op, (unsigned long)vif->tx_comms_area->addr,
1584 GNTMAP_host_map, vif->tx_shmem_handle);
1585
1586 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
1587 BUG();
1588 }
1589
1590 if (vif->rx.sring) {
1591 gnttab_set_unmap_op(&op, (unsigned long)vif->rx_comms_area->addr,
1592 GNTMAP_host_map, vif->rx_shmem_handle);
1593
1594 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
1595 BUG();
1596 }
1597 if (vif->rx_comms_area)
1598 free_vm_area(vif->rx_comms_area);
1599 if (vif->tx_comms_area)
1600 free_vm_area(vif->tx_comms_area);
1601}
1602
1603int xen_netbk_map_frontend_rings(struct xenvif *vif,
1604 grant_ref_t tx_ring_ref,
1605 grant_ref_t rx_ring_ref)
1606{
1607 struct gnttab_map_grant_ref op;
1608 struct xen_netif_tx_sring *txs;
1609 struct xen_netif_rx_sring *rxs;
1610
1611 int err = -ENOMEM;
1612
1613 vif->tx_comms_area = alloc_vm_area(PAGE_SIZE);
1614 if (vif->tx_comms_area == NULL)
1615 goto err;
1616
1617 vif->rx_comms_area = alloc_vm_area(PAGE_SIZE);
1618 if (vif->rx_comms_area == NULL)
1619 goto err;
1620
1621 gnttab_set_map_op(&op, (unsigned long)vif->tx_comms_area->addr,
1622 GNTMAP_host_map, tx_ring_ref, vif->domid);
1623
1624 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
1625 BUG();
1626
1627 if (op.status) {
1628 netdev_warn(vif->dev,
1629 "failed to map tx ring. err=%d status=%d\n",
1630 err, op.status);
1631 err = op.status;
1632 goto err;
1633 }
1634
1635 vif->tx_shmem_ref = tx_ring_ref;
1636 vif->tx_shmem_handle = op.handle;
1637
1638 txs = (struct xen_netif_tx_sring *)vif->tx_comms_area->addr;
1639 BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
1640
1641 gnttab_set_map_op(&op, (unsigned long)vif->rx_comms_area->addr,
1642 GNTMAP_host_map, rx_ring_ref, vif->domid);
1643
1644 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
1645 BUG();
1646
1647 if (op.status) {
1648 netdev_warn(vif->dev,
1649 "failed to map rx ring. err=%d status=%d\n",
1650 err, op.status);
1651 err = op.status;
1652 goto err;
1653 }
1654
1655 vif->rx_shmem_ref = rx_ring_ref;
1656 vif->rx_shmem_handle = op.handle;
1657 vif->rx_req_cons_peek = 0;
1658
1659 rxs = (struct xen_netif_rx_sring *)vif->rx_comms_area->addr;
1660 BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
1661
1662 return 0;
1663
1664err:
1665 xen_netbk_unmap_frontend_rings(vif);
1666 return err;
1667}
1668
1669static int __init netback_init(void)
1670{
1671 int i;
1672 int rc = 0;
1673 int group;
1674
1675 if (!xen_pv_domain())
1676 return -ENODEV;
1677
1678 xen_netbk_group_nr = num_online_cpus();
1679 xen_netbk = vzalloc(sizeof(struct xen_netbk) * xen_netbk_group_nr);
1680 if (!xen_netbk) {
1681 printk(KERN_ALERT "%s: out of memory\n", __func__);
1682 return -ENOMEM;
1683 }
1684
1685 for (group = 0; group < xen_netbk_group_nr; group++) {
1686 struct xen_netbk *netbk = &xen_netbk[group];
1687 skb_queue_head_init(&netbk->rx_queue);
1688 skb_queue_head_init(&netbk->tx_queue);
1689
1690 init_timer(&netbk->net_timer);
1691 netbk->net_timer.data = (unsigned long)netbk;
1692 netbk->net_timer.function = xen_netbk_alarm;
1693
1694 netbk->pending_cons = 0;
1695 netbk->pending_prod = MAX_PENDING_REQS;
1696 for (i = 0; i < MAX_PENDING_REQS; i++)
1697 netbk->pending_ring[i] = i;
1698
1699 init_waitqueue_head(&netbk->wq);
1700 netbk->task = kthread_create(xen_netbk_kthread,
1701 (void *)netbk,
1702 "netback/%u", group);
1703
1704 if (IS_ERR(netbk->task)) {
1705 printk(KERN_ALERT "kthread_run() fails at netback\n");
1706 del_timer(&netbk->net_timer);
1707 rc = PTR_ERR(netbk->task);
1708 goto failed_init;
1709 }
1710
1711 kthread_bind(netbk->task, group);
1712
1713 INIT_LIST_HEAD(&netbk->net_schedule_list);
1714
1715 spin_lock_init(&netbk->net_schedule_list_lock);
1716
1717 atomic_set(&netbk->netfront_count, 0);
1718
1719 wake_up_process(netbk->task);
1720 }
1721
1722 rc = xenvif_xenbus_init();
1723 if (rc)
1724 goto failed_init;
1725
1726 return 0;
1727
1728failed_init:
1729 while (--group >= 0) {
1730 struct xen_netbk *netbk = &xen_netbk[group];
1731 for (i = 0; i < MAX_PENDING_REQS; i++) {
1732 if (netbk->mmap_pages[i])
1733 __free_page(netbk->mmap_pages[i]);
1734 }
1735 del_timer(&netbk->net_timer);
1736 kthread_stop(netbk->task);
1737 }
1738 vfree(xen_netbk);
1739 return rc;
1740
1741}
1742
1743module_init(netback_init);
1744
1745MODULE_LICENSE("Dual BSD/GPL");
1746MODULE_ALIAS("xen-backend:vif");