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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
70unsigned int xenvif_max_queues;
71module_param_named(max_queues, xenvif_max_queues, uint, 0644);
72MODULE_PARM_DESC(max_queues,
73 "Maximum number of queues per virtual interface");
74
75/*
76 * This is the maximum slots a skb can have. If a guest sends a skb
77 * which exceeds this limit it is considered malicious.
78 */
79#define FATAL_SKB_SLOTS_DEFAULT 20
80static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
81module_param(fatal_skb_slots, uint, 0444);
82
83/* The amount to copy out of the first guest Tx slot into the skb's
84 * linear area. If the first slot has more data, it will be mapped
85 * and put into the first frag.
86 *
87 * This is sized to avoid pulling headers from the frags for most
88 * TCP/IP packets.
89 */
90#define XEN_NETBACK_TX_COPY_LEN 128
91
92/* This is the maximum number of flows in the hash cache. */
93#define XENVIF_HASH_CACHE_SIZE_DEFAULT 64
94unsigned int xenvif_hash_cache_size = XENVIF_HASH_CACHE_SIZE_DEFAULT;
95module_param_named(hash_cache_size, xenvif_hash_cache_size, uint, 0644);
96MODULE_PARM_DESC(hash_cache_size, "Number of flows in the hash cache");
97
98static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
99 u8 status);
100
101static void make_tx_response(struct xenvif_queue *queue,
102 struct xen_netif_tx_request *txp,
103 unsigned int extra_count,
104 s8 st);
105static void push_tx_responses(struct xenvif_queue *queue);
106
107static inline int tx_work_todo(struct xenvif_queue *queue);
108
109static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
110 u16 idx)
111{
112 return page_to_pfn(queue->mmap_pages[idx]);
113}
114
115static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
116 u16 idx)
117{
118 return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
119}
120
121#define callback_param(vif, pending_idx) \
122 (vif->pending_tx_info[pending_idx].callback_struct)
123
124/* Find the containing VIF's structure from a pointer in pending_tx_info array
125 */
126static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf)
127{
128 u16 pending_idx = ubuf->desc;
129 struct pending_tx_info *temp =
130 container_of(ubuf, struct pending_tx_info, callback_struct);
131 return container_of(temp - pending_idx,
132 struct xenvif_queue,
133 pending_tx_info[0]);
134}
135
136static u16 frag_get_pending_idx(skb_frag_t *frag)
137{
138 return (u16)frag->page_offset;
139}
140
141static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
142{
143 frag->page_offset = pending_idx;
144}
145
146static inline pending_ring_idx_t pending_index(unsigned i)
147{
148 return i & (MAX_PENDING_REQS-1);
149}
150
151void xenvif_kick_thread(struct xenvif_queue *queue)
152{
153 wake_up(&queue->wq);
154}
155
156void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
157{
158 int more_to_do;
159
160 RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
161
162 if (more_to_do)
163 napi_schedule(&queue->napi);
164}
165
166static void tx_add_credit(struct xenvif_queue *queue)
167{
168 unsigned long max_burst, max_credit;
169
170 /*
171 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
172 * Otherwise the interface can seize up due to insufficient credit.
173 */
174 max_burst = max(131072UL, queue->credit_bytes);
175
176 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
177 max_credit = queue->remaining_credit + queue->credit_bytes;
178 if (max_credit < queue->remaining_credit)
179 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
180
181 queue->remaining_credit = min(max_credit, max_burst);
182}
183
184void xenvif_tx_credit_callback(unsigned long data)
185{
186 struct xenvif_queue *queue = (struct xenvif_queue *)data;
187 tx_add_credit(queue);
188 xenvif_napi_schedule_or_enable_events(queue);
189}
190
191static void xenvif_tx_err(struct xenvif_queue *queue,
192 struct xen_netif_tx_request *txp,
193 unsigned int extra_count, RING_IDX end)
194{
195 RING_IDX cons = queue->tx.req_cons;
196 unsigned long flags;
197
198 do {
199 spin_lock_irqsave(&queue->response_lock, flags);
200 make_tx_response(queue, txp, extra_count, XEN_NETIF_RSP_ERROR);
201 push_tx_responses(queue);
202 spin_unlock_irqrestore(&queue->response_lock, flags);
203 if (cons == end)
204 break;
205 RING_COPY_REQUEST(&queue->tx, cons++, txp);
206 extra_count = 0; /* only the first frag can have extras */
207 } while (1);
208 queue->tx.req_cons = cons;
209}
210
211static void xenvif_fatal_tx_err(struct xenvif *vif)
212{
213 netdev_err(vif->dev, "fatal error; disabling device\n");
214 vif->disabled = true;
215 /* Disable the vif from queue 0's kthread */
216 if (vif->queues)
217 xenvif_kick_thread(&vif->queues[0]);
218}
219
220static int xenvif_count_requests(struct xenvif_queue *queue,
221 struct xen_netif_tx_request *first,
222 unsigned int extra_count,
223 struct xen_netif_tx_request *txp,
224 int work_to_do)
225{
226 RING_IDX cons = queue->tx.req_cons;
227 int slots = 0;
228 int drop_err = 0;
229 int more_data;
230
231 if (!(first->flags & XEN_NETTXF_more_data))
232 return 0;
233
234 do {
235 struct xen_netif_tx_request dropped_tx = { 0 };
236
237 if (slots >= work_to_do) {
238 netdev_err(queue->vif->dev,
239 "Asked for %d slots but exceeds this limit\n",
240 work_to_do);
241 xenvif_fatal_tx_err(queue->vif);
242 return -ENODATA;
243 }
244
245 /* This guest is really using too many slots and
246 * considered malicious.
247 */
248 if (unlikely(slots >= fatal_skb_slots)) {
249 netdev_err(queue->vif->dev,
250 "Malicious frontend using %d slots, threshold %u\n",
251 slots, fatal_skb_slots);
252 xenvif_fatal_tx_err(queue->vif);
253 return -E2BIG;
254 }
255
256 /* Xen network protocol had implicit dependency on
257 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
258 * the historical MAX_SKB_FRAGS value 18 to honor the
259 * same behavior as before. Any packet using more than
260 * 18 slots but less than fatal_skb_slots slots is
261 * dropped
262 */
263 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
264 if (net_ratelimit())
265 netdev_dbg(queue->vif->dev,
266 "Too many slots (%d) exceeding limit (%d), dropping packet\n",
267 slots, XEN_NETBK_LEGACY_SLOTS_MAX);
268 drop_err = -E2BIG;
269 }
270
271 if (drop_err)
272 txp = &dropped_tx;
273
274 RING_COPY_REQUEST(&queue->tx, cons + slots, txp);
275
276 /* If the guest submitted a frame >= 64 KiB then
277 * first->size overflowed and following slots will
278 * appear to be larger than the frame.
279 *
280 * This cannot be fatal error as there are buggy
281 * frontends that do this.
282 *
283 * Consume all slots and drop the packet.
284 */
285 if (!drop_err && txp->size > first->size) {
286 if (net_ratelimit())
287 netdev_dbg(queue->vif->dev,
288 "Invalid tx request, slot size %u > remaining size %u\n",
289 txp->size, first->size);
290 drop_err = -EIO;
291 }
292
293 first->size -= txp->size;
294 slots++;
295
296 if (unlikely((txp->offset + txp->size) > XEN_PAGE_SIZE)) {
297 netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %u, size: %u\n",
298 txp->offset, txp->size);
299 xenvif_fatal_tx_err(queue->vif);
300 return -EINVAL;
301 }
302
303 more_data = txp->flags & XEN_NETTXF_more_data;
304
305 if (!drop_err)
306 txp++;
307
308 } while (more_data);
309
310 if (drop_err) {
311 xenvif_tx_err(queue, first, extra_count, cons + slots);
312 return drop_err;
313 }
314
315 return slots;
316}
317
318
319struct xenvif_tx_cb {
320 u16 pending_idx;
321};
322
323#define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
324
325static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
326 u16 pending_idx,
327 struct xen_netif_tx_request *txp,
328 unsigned int extra_count,
329 struct gnttab_map_grant_ref *mop)
330{
331 queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
332 gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
333 GNTMAP_host_map | GNTMAP_readonly,
334 txp->gref, queue->vif->domid);
335
336 memcpy(&queue->pending_tx_info[pending_idx].req, txp,
337 sizeof(*txp));
338 queue->pending_tx_info[pending_idx].extra_count = extra_count;
339}
340
341static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
342{
343 struct sk_buff *skb =
344 alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
345 GFP_ATOMIC | __GFP_NOWARN);
346 if (unlikely(skb == NULL))
347 return NULL;
348
349 /* Packets passed to netif_rx() must have some headroom. */
350 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
351
352 /* Initialize it here to avoid later surprises */
353 skb_shinfo(skb)->destructor_arg = NULL;
354
355 return skb;
356}
357
358static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue,
359 struct sk_buff *skb,
360 struct xen_netif_tx_request *txp,
361 struct gnttab_map_grant_ref *gop,
362 unsigned int frag_overflow,
363 struct sk_buff *nskb)
364{
365 struct skb_shared_info *shinfo = skb_shinfo(skb);
366 skb_frag_t *frags = shinfo->frags;
367 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
368 int start;
369 pending_ring_idx_t index;
370 unsigned int nr_slots;
371
372 nr_slots = shinfo->nr_frags;
373
374 /* Skip first skb fragment if it is on same page as header fragment. */
375 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
376
377 for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
378 shinfo->nr_frags++, txp++, gop++) {
379 index = pending_index(queue->pending_cons++);
380 pending_idx = queue->pending_ring[index];
381 xenvif_tx_create_map_op(queue, pending_idx, txp, 0, gop);
382 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
383 }
384
385 if (frag_overflow) {
386
387 shinfo = skb_shinfo(nskb);
388 frags = shinfo->frags;
389
390 for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
391 shinfo->nr_frags++, txp++, gop++) {
392 index = pending_index(queue->pending_cons++);
393 pending_idx = queue->pending_ring[index];
394 xenvif_tx_create_map_op(queue, pending_idx, txp, 0,
395 gop);
396 frag_set_pending_idx(&frags[shinfo->nr_frags],
397 pending_idx);
398 }
399
400 skb_shinfo(skb)->frag_list = nskb;
401 }
402
403 return gop;
404}
405
406static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
407 u16 pending_idx,
408 grant_handle_t handle)
409{
410 if (unlikely(queue->grant_tx_handle[pending_idx] !=
411 NETBACK_INVALID_HANDLE)) {
412 netdev_err(queue->vif->dev,
413 "Trying to overwrite active handle! pending_idx: 0x%x\n",
414 pending_idx);
415 BUG();
416 }
417 queue->grant_tx_handle[pending_idx] = handle;
418}
419
420static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
421 u16 pending_idx)
422{
423 if (unlikely(queue->grant_tx_handle[pending_idx] ==
424 NETBACK_INVALID_HANDLE)) {
425 netdev_err(queue->vif->dev,
426 "Trying to unmap invalid handle! pending_idx: 0x%x\n",
427 pending_idx);
428 BUG();
429 }
430 queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
431}
432
433static int xenvif_tx_check_gop(struct xenvif_queue *queue,
434 struct sk_buff *skb,
435 struct gnttab_map_grant_ref **gopp_map,
436 struct gnttab_copy **gopp_copy)
437{
438 struct gnttab_map_grant_ref *gop_map = *gopp_map;
439 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
440 /* This always points to the shinfo of the skb being checked, which
441 * could be either the first or the one on the frag_list
442 */
443 struct skb_shared_info *shinfo = skb_shinfo(skb);
444 /* If this is non-NULL, we are currently checking the frag_list skb, and
445 * this points to the shinfo of the first one
446 */
447 struct skb_shared_info *first_shinfo = NULL;
448 int nr_frags = shinfo->nr_frags;
449 const bool sharedslot = nr_frags &&
450 frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
451 int i, err;
452
453 /* Check status of header. */
454 err = (*gopp_copy)->status;
455 if (unlikely(err)) {
456 if (net_ratelimit())
457 netdev_dbg(queue->vif->dev,
458 "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
459 (*gopp_copy)->status,
460 pending_idx,
461 (*gopp_copy)->source.u.ref);
462 /* The first frag might still have this slot mapped */
463 if (!sharedslot)
464 xenvif_idx_release(queue, pending_idx,
465 XEN_NETIF_RSP_ERROR);
466 }
467 (*gopp_copy)++;
468
469check_frags:
470 for (i = 0; i < nr_frags; i++, gop_map++) {
471 int j, newerr;
472
473 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
474
475 /* Check error status: if okay then remember grant handle. */
476 newerr = gop_map->status;
477
478 if (likely(!newerr)) {
479 xenvif_grant_handle_set(queue,
480 pending_idx,
481 gop_map->handle);
482 /* Had a previous error? Invalidate this fragment. */
483 if (unlikely(err)) {
484 xenvif_idx_unmap(queue, pending_idx);
485 /* If the mapping of the first frag was OK, but
486 * the header's copy failed, and they are
487 * sharing a slot, send an error
488 */
489 if (i == 0 && sharedslot)
490 xenvif_idx_release(queue, pending_idx,
491 XEN_NETIF_RSP_ERROR);
492 else
493 xenvif_idx_release(queue, pending_idx,
494 XEN_NETIF_RSP_OKAY);
495 }
496 continue;
497 }
498
499 /* Error on this fragment: respond to client with an error. */
500 if (net_ratelimit())
501 netdev_dbg(queue->vif->dev,
502 "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
503 i,
504 gop_map->status,
505 pending_idx,
506 gop_map->ref);
507
508 xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
509
510 /* Not the first error? Preceding frags already invalidated. */
511 if (err)
512 continue;
513
514 /* First error: if the header haven't shared a slot with the
515 * first frag, release it as well.
516 */
517 if (!sharedslot)
518 xenvif_idx_release(queue,
519 XENVIF_TX_CB(skb)->pending_idx,
520 XEN_NETIF_RSP_OKAY);
521
522 /* Invalidate preceding fragments of this skb. */
523 for (j = 0; j < i; j++) {
524 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
525 xenvif_idx_unmap(queue, pending_idx);
526 xenvif_idx_release(queue, pending_idx,
527 XEN_NETIF_RSP_OKAY);
528 }
529
530 /* And if we found the error while checking the frag_list, unmap
531 * the first skb's frags
532 */
533 if (first_shinfo) {
534 for (j = 0; j < first_shinfo->nr_frags; j++) {
535 pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
536 xenvif_idx_unmap(queue, pending_idx);
537 xenvif_idx_release(queue, pending_idx,
538 XEN_NETIF_RSP_OKAY);
539 }
540 }
541
542 /* Remember the error: invalidate all subsequent fragments. */
543 err = newerr;
544 }
545
546 if (skb_has_frag_list(skb) && !first_shinfo) {
547 first_shinfo = skb_shinfo(skb);
548 shinfo = skb_shinfo(skb_shinfo(skb)->frag_list);
549 nr_frags = shinfo->nr_frags;
550
551 goto check_frags;
552 }
553
554 *gopp_map = gop_map;
555 return err;
556}
557
558static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
559{
560 struct skb_shared_info *shinfo = skb_shinfo(skb);
561 int nr_frags = shinfo->nr_frags;
562 int i;
563 u16 prev_pending_idx = INVALID_PENDING_IDX;
564
565 for (i = 0; i < nr_frags; i++) {
566 skb_frag_t *frag = shinfo->frags + i;
567 struct xen_netif_tx_request *txp;
568 struct page *page;
569 u16 pending_idx;
570
571 pending_idx = frag_get_pending_idx(frag);
572
573 /* If this is not the first frag, chain it to the previous*/
574 if (prev_pending_idx == INVALID_PENDING_IDX)
575 skb_shinfo(skb)->destructor_arg =
576 &callback_param(queue, pending_idx);
577 else
578 callback_param(queue, prev_pending_idx).ctx =
579 &callback_param(queue, pending_idx);
580
581 callback_param(queue, pending_idx).ctx = NULL;
582 prev_pending_idx = pending_idx;
583
584 txp = &queue->pending_tx_info[pending_idx].req;
585 page = virt_to_page(idx_to_kaddr(queue, pending_idx));
586 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
587 skb->len += txp->size;
588 skb->data_len += txp->size;
589 skb->truesize += txp->size;
590
591 /* Take an extra reference to offset network stack's put_page */
592 get_page(queue->mmap_pages[pending_idx]);
593 }
594}
595
596static int xenvif_get_extras(struct xenvif_queue *queue,
597 struct xen_netif_extra_info *extras,
598 unsigned int *extra_count,
599 int work_to_do)
600{
601 struct xen_netif_extra_info extra;
602 RING_IDX cons = queue->tx.req_cons;
603
604 do {
605 if (unlikely(work_to_do-- <= 0)) {
606 netdev_err(queue->vif->dev, "Missing extra info\n");
607 xenvif_fatal_tx_err(queue->vif);
608 return -EBADR;
609 }
610
611 RING_COPY_REQUEST(&queue->tx, cons, &extra);
612
613 queue->tx.req_cons = ++cons;
614 (*extra_count)++;
615
616 if (unlikely(!extra.type ||
617 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
618 netdev_err(queue->vif->dev,
619 "Invalid extra type: %d\n", extra.type);
620 xenvif_fatal_tx_err(queue->vif);
621 return -EINVAL;
622 }
623
624 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
625 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
626
627 return work_to_do;
628}
629
630static int xenvif_set_skb_gso(struct xenvif *vif,
631 struct sk_buff *skb,
632 struct xen_netif_extra_info *gso)
633{
634 if (!gso->u.gso.size) {
635 netdev_err(vif->dev, "GSO size must not be zero.\n");
636 xenvif_fatal_tx_err(vif);
637 return -EINVAL;
638 }
639
640 switch (gso->u.gso.type) {
641 case XEN_NETIF_GSO_TYPE_TCPV4:
642 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
643 break;
644 case XEN_NETIF_GSO_TYPE_TCPV6:
645 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
646 break;
647 default:
648 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
649 xenvif_fatal_tx_err(vif);
650 return -EINVAL;
651 }
652
653 skb_shinfo(skb)->gso_size = gso->u.gso.size;
654 /* gso_segs will be calculated later */
655
656 return 0;
657}
658
659static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb)
660{
661 bool recalculate_partial_csum = false;
662
663 /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
664 * peers can fail to set NETRXF_csum_blank when sending a GSO
665 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
666 * recalculate the partial checksum.
667 */
668 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
669 queue->stats.rx_gso_checksum_fixup++;
670 skb->ip_summed = CHECKSUM_PARTIAL;
671 recalculate_partial_csum = true;
672 }
673
674 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
675 if (skb->ip_summed != CHECKSUM_PARTIAL)
676 return 0;
677
678 return skb_checksum_setup(skb, recalculate_partial_csum);
679}
680
681static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
682{
683 u64 now = get_jiffies_64();
684 u64 next_credit = queue->credit_window_start +
685 msecs_to_jiffies(queue->credit_usec / 1000);
686
687 /* Timer could already be pending in rare cases. */
688 if (timer_pending(&queue->credit_timeout))
689 return true;
690
691 /* Passed the point where we can replenish credit? */
692 if (time_after_eq64(now, next_credit)) {
693 queue->credit_window_start = now;
694 tx_add_credit(queue);
695 }
696
697 /* Still too big to send right now? Set a callback. */
698 if (size > queue->remaining_credit) {
699 queue->credit_timeout.data =
700 (unsigned long)queue;
701 mod_timer(&queue->credit_timeout,
702 next_credit);
703 queue->credit_window_start = next_credit;
704
705 return true;
706 }
707
708 return false;
709}
710
711/* No locking is required in xenvif_mcast_add/del() as they are
712 * only ever invoked from NAPI poll. An RCU list is used because
713 * xenvif_mcast_match() is called asynchronously, during start_xmit.
714 */
715
716static int xenvif_mcast_add(struct xenvif *vif, const u8 *addr)
717{
718 struct xenvif_mcast_addr *mcast;
719
720 if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) {
721 if (net_ratelimit())
722 netdev_err(vif->dev,
723 "Too many multicast addresses\n");
724 return -ENOSPC;
725 }
726
727 mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC);
728 if (!mcast)
729 return -ENOMEM;
730
731 ether_addr_copy(mcast->addr, addr);
732 list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr);
733 vif->fe_mcast_count++;
734
735 return 0;
736}
737
738static void xenvif_mcast_del(struct xenvif *vif, const u8 *addr)
739{
740 struct xenvif_mcast_addr *mcast;
741
742 list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
743 if (ether_addr_equal(addr, mcast->addr)) {
744 --vif->fe_mcast_count;
745 list_del_rcu(&mcast->entry);
746 kfree_rcu(mcast, rcu);
747 break;
748 }
749 }
750}
751
752bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr)
753{
754 struct xenvif_mcast_addr *mcast;
755
756 rcu_read_lock();
757 list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
758 if (ether_addr_equal(addr, mcast->addr)) {
759 rcu_read_unlock();
760 return true;
761 }
762 }
763 rcu_read_unlock();
764
765 return false;
766}
767
768void xenvif_mcast_addr_list_free(struct xenvif *vif)
769{
770 /* No need for locking or RCU here. NAPI poll and TX queue
771 * are stopped.
772 */
773 while (!list_empty(&vif->fe_mcast_addr)) {
774 struct xenvif_mcast_addr *mcast;
775
776 mcast = list_first_entry(&vif->fe_mcast_addr,
777 struct xenvif_mcast_addr,
778 entry);
779 --vif->fe_mcast_count;
780 list_del(&mcast->entry);
781 kfree(mcast);
782 }
783}
784
785static void xenvif_tx_build_gops(struct xenvif_queue *queue,
786 int budget,
787 unsigned *copy_ops,
788 unsigned *map_ops)
789{
790 struct gnttab_map_grant_ref *gop = queue->tx_map_ops;
791 struct sk_buff *skb, *nskb;
792 int ret;
793 unsigned int frag_overflow;
794
795 while (skb_queue_len(&queue->tx_queue) < budget) {
796 struct xen_netif_tx_request txreq;
797 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
798 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
799 unsigned int extra_count;
800 u16 pending_idx;
801 RING_IDX idx;
802 int work_to_do;
803 unsigned int data_len;
804 pending_ring_idx_t index;
805
806 if (queue->tx.sring->req_prod - queue->tx.req_cons >
807 XEN_NETIF_TX_RING_SIZE) {
808 netdev_err(queue->vif->dev,
809 "Impossible number of requests. "
810 "req_prod %d, req_cons %d, size %ld\n",
811 queue->tx.sring->req_prod, queue->tx.req_cons,
812 XEN_NETIF_TX_RING_SIZE);
813 xenvif_fatal_tx_err(queue->vif);
814 break;
815 }
816
817 work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
818 if (!work_to_do)
819 break;
820
821 idx = queue->tx.req_cons;
822 rmb(); /* Ensure that we see the request before we copy it. */
823 RING_COPY_REQUEST(&queue->tx, idx, &txreq);
824
825 /* Credit-based scheduling. */
826 if (txreq.size > queue->remaining_credit &&
827 tx_credit_exceeded(queue, txreq.size))
828 break;
829
830 queue->remaining_credit -= txreq.size;
831
832 work_to_do--;
833 queue->tx.req_cons = ++idx;
834
835 memset(extras, 0, sizeof(extras));
836 extra_count = 0;
837 if (txreq.flags & XEN_NETTXF_extra_info) {
838 work_to_do = xenvif_get_extras(queue, extras,
839 &extra_count,
840 work_to_do);
841 idx = queue->tx.req_cons;
842 if (unlikely(work_to_do < 0))
843 break;
844 }
845
846 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) {
847 struct xen_netif_extra_info *extra;
848
849 extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
850 ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
851
852 make_tx_response(queue, &txreq, extra_count,
853 (ret == 0) ?
854 XEN_NETIF_RSP_OKAY :
855 XEN_NETIF_RSP_ERROR);
856 push_tx_responses(queue);
857 continue;
858 }
859
860 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) {
861 struct xen_netif_extra_info *extra;
862
863 extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
864 xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
865
866 make_tx_response(queue, &txreq, extra_count,
867 XEN_NETIF_RSP_OKAY);
868 push_tx_responses(queue);
869 continue;
870 }
871
872 ret = xenvif_count_requests(queue, &txreq, extra_count,
873 txfrags, work_to_do);
874 if (unlikely(ret < 0))
875 break;
876
877 idx += ret;
878
879 if (unlikely(txreq.size < ETH_HLEN)) {
880 netdev_dbg(queue->vif->dev,
881 "Bad packet size: %d\n", txreq.size);
882 xenvif_tx_err(queue, &txreq, extra_count, idx);
883 break;
884 }
885
886 /* No crossing a page as the payload mustn't fragment. */
887 if (unlikely((txreq.offset + txreq.size) > XEN_PAGE_SIZE)) {
888 netdev_err(queue->vif->dev,
889 "txreq.offset: %u, size: %u, end: %lu\n",
890 txreq.offset, txreq.size,
891 (unsigned long)(txreq.offset&~XEN_PAGE_MASK) + txreq.size);
892 xenvif_fatal_tx_err(queue->vif);
893 break;
894 }
895
896 index = pending_index(queue->pending_cons);
897 pending_idx = queue->pending_ring[index];
898
899 data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN &&
900 ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
901 XEN_NETBACK_TX_COPY_LEN : txreq.size;
902
903 skb = xenvif_alloc_skb(data_len);
904 if (unlikely(skb == NULL)) {
905 netdev_dbg(queue->vif->dev,
906 "Can't allocate a skb in start_xmit.\n");
907 xenvif_tx_err(queue, &txreq, extra_count, idx);
908 break;
909 }
910
911 skb_shinfo(skb)->nr_frags = ret;
912 if (data_len < txreq.size)
913 skb_shinfo(skb)->nr_frags++;
914 /* At this point shinfo->nr_frags is in fact the number of
915 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
916 */
917 frag_overflow = 0;
918 nskb = NULL;
919 if (skb_shinfo(skb)->nr_frags > MAX_SKB_FRAGS) {
920 frag_overflow = skb_shinfo(skb)->nr_frags - MAX_SKB_FRAGS;
921 BUG_ON(frag_overflow > MAX_SKB_FRAGS);
922 skb_shinfo(skb)->nr_frags = MAX_SKB_FRAGS;
923 nskb = xenvif_alloc_skb(0);
924 if (unlikely(nskb == NULL)) {
925 kfree_skb(skb);
926 xenvif_tx_err(queue, &txreq, extra_count, idx);
927 if (net_ratelimit())
928 netdev_err(queue->vif->dev,
929 "Can't allocate the frag_list skb.\n");
930 break;
931 }
932 }
933
934 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
935 struct xen_netif_extra_info *gso;
936 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
937
938 if (xenvif_set_skb_gso(queue->vif, skb, gso)) {
939 /* Failure in xenvif_set_skb_gso is fatal. */
940 kfree_skb(skb);
941 kfree_skb(nskb);
942 break;
943 }
944 }
945
946 if (extras[XEN_NETIF_EXTRA_TYPE_HASH - 1].type) {
947 struct xen_netif_extra_info *extra;
948 enum pkt_hash_types type = PKT_HASH_TYPE_NONE;
949
950 extra = &extras[XEN_NETIF_EXTRA_TYPE_HASH - 1];
951
952 switch (extra->u.hash.type) {
953 case _XEN_NETIF_CTRL_HASH_TYPE_IPV4:
954 case _XEN_NETIF_CTRL_HASH_TYPE_IPV6:
955 type = PKT_HASH_TYPE_L3;
956 break;
957
958 case _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP:
959 case _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP:
960 type = PKT_HASH_TYPE_L4;
961 break;
962
963 default:
964 break;
965 }
966
967 if (type != PKT_HASH_TYPE_NONE)
968 skb_set_hash(skb,
969 *(u32 *)extra->u.hash.value,
970 type);
971 }
972
973 XENVIF_TX_CB(skb)->pending_idx = pending_idx;
974
975 __skb_put(skb, data_len);
976 queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
977 queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid;
978 queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
979
980 queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
981 virt_to_gfn(skb->data);
982 queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
983 queue->tx_copy_ops[*copy_ops].dest.offset =
984 offset_in_page(skb->data) & ~XEN_PAGE_MASK;
985
986 queue->tx_copy_ops[*copy_ops].len = data_len;
987 queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
988
989 (*copy_ops)++;
990
991 if (data_len < txreq.size) {
992 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
993 pending_idx);
994 xenvif_tx_create_map_op(queue, pending_idx, &txreq,
995 extra_count, gop);
996 gop++;
997 } else {
998 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
999 INVALID_PENDING_IDX);
1000 memcpy(&queue->pending_tx_info[pending_idx].req,
1001 &txreq, sizeof(txreq));
1002 queue->pending_tx_info[pending_idx].extra_count =
1003 extra_count;
1004 }
1005
1006 queue->pending_cons++;
1007
1008 gop = xenvif_get_requests(queue, skb, txfrags, gop,
1009 frag_overflow, nskb);
1010
1011 __skb_queue_tail(&queue->tx_queue, skb);
1012
1013 queue->tx.req_cons = idx;
1014
1015 if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) ||
1016 (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
1017 break;
1018 }
1019
1020 (*map_ops) = gop - queue->tx_map_ops;
1021 return;
1022}
1023
1024/* Consolidate skb with a frag_list into a brand new one with local pages on
1025 * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1026 */
1027static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb)
1028{
1029 unsigned int offset = skb_headlen(skb);
1030 skb_frag_t frags[MAX_SKB_FRAGS];
1031 int i, f;
1032 struct ubuf_info *uarg;
1033 struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1034
1035 queue->stats.tx_zerocopy_sent += 2;
1036 queue->stats.tx_frag_overflow++;
1037
1038 xenvif_fill_frags(queue, nskb);
1039 /* Subtract frags size, we will correct it later */
1040 skb->truesize -= skb->data_len;
1041 skb->len += nskb->len;
1042 skb->data_len += nskb->len;
1043
1044 /* create a brand new frags array and coalesce there */
1045 for (i = 0; offset < skb->len; i++) {
1046 struct page *page;
1047 unsigned int len;
1048
1049 BUG_ON(i >= MAX_SKB_FRAGS);
1050 page = alloc_page(GFP_ATOMIC);
1051 if (!page) {
1052 int j;
1053 skb->truesize += skb->data_len;
1054 for (j = 0; j < i; j++)
1055 put_page(frags[j].page.p);
1056 return -ENOMEM;
1057 }
1058
1059 if (offset + PAGE_SIZE < skb->len)
1060 len = PAGE_SIZE;
1061 else
1062 len = skb->len - offset;
1063 if (skb_copy_bits(skb, offset, page_address(page), len))
1064 BUG();
1065
1066 offset += len;
1067 frags[i].page.p = page;
1068 frags[i].page_offset = 0;
1069 skb_frag_size_set(&frags[i], len);
1070 }
1071
1072 /* Copied all the bits from the frag list -- free it. */
1073 skb_frag_list_init(skb);
1074 xenvif_skb_zerocopy_prepare(queue, nskb);
1075 kfree_skb(nskb);
1076
1077 /* Release all the original (foreign) frags. */
1078 for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
1079 skb_frag_unref(skb, f);
1080 uarg = skb_shinfo(skb)->destructor_arg;
1081 /* increase inflight counter to offset decrement in callback */
1082 atomic_inc(&queue->inflight_packets);
1083 uarg->callback(uarg, true);
1084 skb_shinfo(skb)->destructor_arg = NULL;
1085
1086 /* Fill the skb with the new (local) frags. */
1087 memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t));
1088 skb_shinfo(skb)->nr_frags = i;
1089 skb->truesize += i * PAGE_SIZE;
1090
1091 return 0;
1092}
1093
1094static int xenvif_tx_submit(struct xenvif_queue *queue)
1095{
1096 struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops;
1097 struct gnttab_copy *gop_copy = queue->tx_copy_ops;
1098 struct sk_buff *skb;
1099 int work_done = 0;
1100
1101 while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
1102 struct xen_netif_tx_request *txp;
1103 u16 pending_idx;
1104 unsigned data_len;
1105
1106 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1107 txp = &queue->pending_tx_info[pending_idx].req;
1108
1109 /* Check the remap error code. */
1110 if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
1111 /* If there was an error, xenvif_tx_check_gop is
1112 * expected to release all the frags which were mapped,
1113 * so kfree_skb shouldn't do it again
1114 */
1115 skb_shinfo(skb)->nr_frags = 0;
1116 if (skb_has_frag_list(skb)) {
1117 struct sk_buff *nskb =
1118 skb_shinfo(skb)->frag_list;
1119 skb_shinfo(nskb)->nr_frags = 0;
1120 }
1121 kfree_skb(skb);
1122 continue;
1123 }
1124
1125 data_len = skb->len;
1126 callback_param(queue, pending_idx).ctx = NULL;
1127 if (data_len < txp->size) {
1128 /* Append the packet payload as a fragment. */
1129 txp->offset += data_len;
1130 txp->size -= data_len;
1131 } else {
1132 /* Schedule a response immediately. */
1133 xenvif_idx_release(queue, pending_idx,
1134 XEN_NETIF_RSP_OKAY);
1135 }
1136
1137 if (txp->flags & XEN_NETTXF_csum_blank)
1138 skb->ip_summed = CHECKSUM_PARTIAL;
1139 else if (txp->flags & XEN_NETTXF_data_validated)
1140 skb->ip_summed = CHECKSUM_UNNECESSARY;
1141
1142 xenvif_fill_frags(queue, skb);
1143
1144 if (unlikely(skb_has_frag_list(skb))) {
1145 if (xenvif_handle_frag_list(queue, skb)) {
1146 if (net_ratelimit())
1147 netdev_err(queue->vif->dev,
1148 "Not enough memory to consolidate frag_list!\n");
1149 xenvif_skb_zerocopy_prepare(queue, skb);
1150 kfree_skb(skb);
1151 continue;
1152 }
1153 }
1154
1155 skb->dev = queue->vif->dev;
1156 skb->protocol = eth_type_trans(skb, skb->dev);
1157 skb_reset_network_header(skb);
1158
1159 if (checksum_setup(queue, skb)) {
1160 netdev_dbg(queue->vif->dev,
1161 "Can't setup checksum in net_tx_action\n");
1162 /* We have to set this flag to trigger the callback */
1163 if (skb_shinfo(skb)->destructor_arg)
1164 xenvif_skb_zerocopy_prepare(queue, skb);
1165 kfree_skb(skb);
1166 continue;
1167 }
1168
1169 skb_probe_transport_header(skb, 0);
1170
1171 /* If the packet is GSO then we will have just set up the
1172 * transport header offset in checksum_setup so it's now
1173 * straightforward to calculate gso_segs.
1174 */
1175 if (skb_is_gso(skb)) {
1176 int mss = skb_shinfo(skb)->gso_size;
1177 int hdrlen = skb_transport_header(skb) -
1178 skb_mac_header(skb) +
1179 tcp_hdrlen(skb);
1180
1181 skb_shinfo(skb)->gso_segs =
1182 DIV_ROUND_UP(skb->len - hdrlen, mss);
1183 }
1184
1185 queue->stats.rx_bytes += skb->len;
1186 queue->stats.rx_packets++;
1187
1188 work_done++;
1189
1190 /* Set this flag right before netif_receive_skb, otherwise
1191 * someone might think this packet already left netback, and
1192 * do a skb_copy_ubufs while we are still in control of the
1193 * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1194 */
1195 if (skb_shinfo(skb)->destructor_arg) {
1196 xenvif_skb_zerocopy_prepare(queue, skb);
1197 queue->stats.tx_zerocopy_sent++;
1198 }
1199
1200 netif_receive_skb(skb);
1201 }
1202
1203 return work_done;
1204}
1205
1206void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success)
1207{
1208 unsigned long flags;
1209 pending_ring_idx_t index;
1210 struct xenvif_queue *queue = ubuf_to_queue(ubuf);
1211
1212 /* This is the only place where we grab this lock, to protect callbacks
1213 * from each other.
1214 */
1215 spin_lock_irqsave(&queue->callback_lock, flags);
1216 do {
1217 u16 pending_idx = ubuf->desc;
1218 ubuf = (struct ubuf_info *) ubuf->ctx;
1219 BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
1220 MAX_PENDING_REQS);
1221 index = pending_index(queue->dealloc_prod);
1222 queue->dealloc_ring[index] = pending_idx;
1223 /* Sync with xenvif_tx_dealloc_action:
1224 * insert idx then incr producer.
1225 */
1226 smp_wmb();
1227 queue->dealloc_prod++;
1228 } while (ubuf);
1229 spin_unlock_irqrestore(&queue->callback_lock, flags);
1230
1231 if (likely(zerocopy_success))
1232 queue->stats.tx_zerocopy_success++;
1233 else
1234 queue->stats.tx_zerocopy_fail++;
1235 xenvif_skb_zerocopy_complete(queue);
1236}
1237
1238static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
1239{
1240 struct gnttab_unmap_grant_ref *gop;
1241 pending_ring_idx_t dc, dp;
1242 u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1243 unsigned int i = 0;
1244
1245 dc = queue->dealloc_cons;
1246 gop = queue->tx_unmap_ops;
1247
1248 /* Free up any grants we have finished using */
1249 do {
1250 dp = queue->dealloc_prod;
1251
1252 /* Ensure we see all indices enqueued by all
1253 * xenvif_zerocopy_callback().
1254 */
1255 smp_rmb();
1256
1257 while (dc != dp) {
1258 BUG_ON(gop - queue->tx_unmap_ops >= MAX_PENDING_REQS);
1259 pending_idx =
1260 queue->dealloc_ring[pending_index(dc++)];
1261
1262 pending_idx_release[gop - queue->tx_unmap_ops] =
1263 pending_idx;
1264 queue->pages_to_unmap[gop - queue->tx_unmap_ops] =
1265 queue->mmap_pages[pending_idx];
1266 gnttab_set_unmap_op(gop,
1267 idx_to_kaddr(queue, pending_idx),
1268 GNTMAP_host_map,
1269 queue->grant_tx_handle[pending_idx]);
1270 xenvif_grant_handle_reset(queue, pending_idx);
1271 ++gop;
1272 }
1273
1274 } while (dp != queue->dealloc_prod);
1275
1276 queue->dealloc_cons = dc;
1277
1278 if (gop - queue->tx_unmap_ops > 0) {
1279 int ret;
1280 ret = gnttab_unmap_refs(queue->tx_unmap_ops,
1281 NULL,
1282 queue->pages_to_unmap,
1283 gop - queue->tx_unmap_ops);
1284 if (ret) {
1285 netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tu ret %d\n",
1286 gop - queue->tx_unmap_ops, ret);
1287 for (i = 0; i < gop - queue->tx_unmap_ops; ++i) {
1288 if (gop[i].status != GNTST_okay)
1289 netdev_err(queue->vif->dev,
1290 " host_addr: 0x%llx handle: 0x%x status: %d\n",
1291 gop[i].host_addr,
1292 gop[i].handle,
1293 gop[i].status);
1294 }
1295 BUG();
1296 }
1297 }
1298
1299 for (i = 0; i < gop - queue->tx_unmap_ops; ++i)
1300 xenvif_idx_release(queue, pending_idx_release[i],
1301 XEN_NETIF_RSP_OKAY);
1302}
1303
1304
1305/* Called after netfront has transmitted */
1306int xenvif_tx_action(struct xenvif_queue *queue, int budget)
1307{
1308 unsigned nr_mops, nr_cops = 0;
1309 int work_done, ret;
1310
1311 if (unlikely(!tx_work_todo(queue)))
1312 return 0;
1313
1314 xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops);
1315
1316 if (nr_cops == 0)
1317 return 0;
1318
1319 gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
1320 if (nr_mops != 0) {
1321 ret = gnttab_map_refs(queue->tx_map_ops,
1322 NULL,
1323 queue->pages_to_map,
1324 nr_mops);
1325 BUG_ON(ret);
1326 }
1327
1328 work_done = xenvif_tx_submit(queue);
1329
1330 return work_done;
1331}
1332
1333static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
1334 u8 status)
1335{
1336 struct pending_tx_info *pending_tx_info;
1337 pending_ring_idx_t index;
1338 unsigned long flags;
1339
1340 pending_tx_info = &queue->pending_tx_info[pending_idx];
1341
1342 spin_lock_irqsave(&queue->response_lock, flags);
1343
1344 make_tx_response(queue, &pending_tx_info->req,
1345 pending_tx_info->extra_count, status);
1346
1347 /* Release the pending index before pusing the Tx response so
1348 * its available before a new Tx request is pushed by the
1349 * frontend.
1350 */
1351 index = pending_index(queue->pending_prod++);
1352 queue->pending_ring[index] = pending_idx;
1353
1354 push_tx_responses(queue);
1355
1356 spin_unlock_irqrestore(&queue->response_lock, flags);
1357}
1358
1359
1360static void make_tx_response(struct xenvif_queue *queue,
1361 struct xen_netif_tx_request *txp,
1362 unsigned int extra_count,
1363 s8 st)
1364{
1365 RING_IDX i = queue->tx.rsp_prod_pvt;
1366 struct xen_netif_tx_response *resp;
1367
1368 resp = RING_GET_RESPONSE(&queue->tx, i);
1369 resp->id = txp->id;
1370 resp->status = st;
1371
1372 while (extra_count-- != 0)
1373 RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1374
1375 queue->tx.rsp_prod_pvt = ++i;
1376}
1377
1378static void push_tx_responses(struct xenvif_queue *queue)
1379{
1380 int notify;
1381
1382 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
1383 if (notify)
1384 notify_remote_via_irq(queue->tx_irq);
1385}
1386
1387void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
1388{
1389 int ret;
1390 struct gnttab_unmap_grant_ref tx_unmap_op;
1391
1392 gnttab_set_unmap_op(&tx_unmap_op,
1393 idx_to_kaddr(queue, pending_idx),
1394 GNTMAP_host_map,
1395 queue->grant_tx_handle[pending_idx]);
1396 xenvif_grant_handle_reset(queue, pending_idx);
1397
1398 ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1399 &queue->mmap_pages[pending_idx], 1);
1400 if (ret) {
1401 netdev_err(queue->vif->dev,
1402 "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: 0x%x status: %d\n",
1403 ret,
1404 pending_idx,
1405 tx_unmap_op.host_addr,
1406 tx_unmap_op.handle,
1407 tx_unmap_op.status);
1408 BUG();
1409 }
1410}
1411
1412static inline int tx_work_todo(struct xenvif_queue *queue)
1413{
1414 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
1415 return 1;
1416
1417 return 0;
1418}
1419
1420static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
1421{
1422 return queue->dealloc_cons != queue->dealloc_prod;
1423}
1424
1425void xenvif_unmap_frontend_data_rings(struct xenvif_queue *queue)
1426{
1427 if (queue->tx.sring)
1428 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1429 queue->tx.sring);
1430 if (queue->rx.sring)
1431 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1432 queue->rx.sring);
1433}
1434
1435int xenvif_map_frontend_data_rings(struct xenvif_queue *queue,
1436 grant_ref_t tx_ring_ref,
1437 grant_ref_t rx_ring_ref)
1438{
1439 void *addr;
1440 struct xen_netif_tx_sring *txs;
1441 struct xen_netif_rx_sring *rxs;
1442
1443 int err = -ENOMEM;
1444
1445 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1446 &tx_ring_ref, 1, &addr);
1447 if (err)
1448 goto err;
1449
1450 txs = (struct xen_netif_tx_sring *)addr;
1451 BACK_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);
1452
1453 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1454 &rx_ring_ref, 1, &addr);
1455 if (err)
1456 goto err;
1457
1458 rxs = (struct xen_netif_rx_sring *)addr;
1459 BACK_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
1460
1461 return 0;
1462
1463err:
1464 xenvif_unmap_frontend_data_rings(queue);
1465 return err;
1466}
1467
1468static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue)
1469{
1470 /* Dealloc thread must remain running until all inflight
1471 * packets complete.
1472 */
1473 return kthread_should_stop() &&
1474 !atomic_read(&queue->inflight_packets);
1475}
1476
1477int xenvif_dealloc_kthread(void *data)
1478{
1479 struct xenvif_queue *queue = data;
1480
1481 for (;;) {
1482 wait_event_interruptible(queue->dealloc_wq,
1483 tx_dealloc_work_todo(queue) ||
1484 xenvif_dealloc_kthread_should_stop(queue));
1485 if (xenvif_dealloc_kthread_should_stop(queue))
1486 break;
1487
1488 xenvif_tx_dealloc_action(queue);
1489 cond_resched();
1490 }
1491
1492 /* Unmap anything remaining*/
1493 if (tx_dealloc_work_todo(queue))
1494 xenvif_tx_dealloc_action(queue);
1495
1496 return 0;
1497}
1498
1499static void make_ctrl_response(struct xenvif *vif,
1500 const struct xen_netif_ctrl_request *req,
1501 u32 status, u32 data)
1502{
1503 RING_IDX idx = vif->ctrl.rsp_prod_pvt;
1504 struct xen_netif_ctrl_response rsp = {
1505 .id = req->id,
1506 .type = req->type,
1507 .status = status,
1508 .data = data,
1509 };
1510
1511 *RING_GET_RESPONSE(&vif->ctrl, idx) = rsp;
1512 vif->ctrl.rsp_prod_pvt = ++idx;
1513}
1514
1515static void push_ctrl_response(struct xenvif *vif)
1516{
1517 int notify;
1518
1519 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->ctrl, notify);
1520 if (notify)
1521 notify_remote_via_irq(vif->ctrl_irq);
1522}
1523
1524static void process_ctrl_request(struct xenvif *vif,
1525 const struct xen_netif_ctrl_request *req)
1526{
1527 u32 status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED;
1528 u32 data = 0;
1529
1530 switch (req->type) {
1531 case XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM:
1532 status = xenvif_set_hash_alg(vif, req->data[0]);
1533 break;
1534
1535 case XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS:
1536 status = xenvif_get_hash_flags(vif, &data);
1537 break;
1538
1539 case XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS:
1540 status = xenvif_set_hash_flags(vif, req->data[0]);
1541 break;
1542
1543 case XEN_NETIF_CTRL_TYPE_SET_HASH_KEY:
1544 status = xenvif_set_hash_key(vif, req->data[0],
1545 req->data[1]);
1546 break;
1547
1548 case XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE:
1549 status = XEN_NETIF_CTRL_STATUS_SUCCESS;
1550 data = XEN_NETBK_MAX_HASH_MAPPING_SIZE;
1551 break;
1552
1553 case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE:
1554 status = xenvif_set_hash_mapping_size(vif,
1555 req->data[0]);
1556 break;
1557
1558 case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING:
1559 status = xenvif_set_hash_mapping(vif, req->data[0],
1560 req->data[1],
1561 req->data[2]);
1562 break;
1563
1564 default:
1565 break;
1566 }
1567
1568 make_ctrl_response(vif, req, status, data);
1569 push_ctrl_response(vif);
1570}
1571
1572static void xenvif_ctrl_action(struct xenvif *vif)
1573{
1574 for (;;) {
1575 RING_IDX req_prod, req_cons;
1576
1577 req_prod = vif->ctrl.sring->req_prod;
1578 req_cons = vif->ctrl.req_cons;
1579
1580 /* Make sure we can see requests before we process them. */
1581 rmb();
1582
1583 if (req_cons == req_prod)
1584 break;
1585
1586 while (req_cons != req_prod) {
1587 struct xen_netif_ctrl_request req;
1588
1589 RING_COPY_REQUEST(&vif->ctrl, req_cons, &req);
1590 req_cons++;
1591
1592 process_ctrl_request(vif, &req);
1593 }
1594
1595 vif->ctrl.req_cons = req_cons;
1596 vif->ctrl.sring->req_event = req_cons + 1;
1597 }
1598}
1599
1600static bool xenvif_ctrl_work_todo(struct xenvif *vif)
1601{
1602 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->ctrl)))
1603 return 1;
1604
1605 return 0;
1606}
1607
1608irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data)
1609{
1610 struct xenvif *vif = data;
1611
1612 while (xenvif_ctrl_work_todo(vif))
1613 xenvif_ctrl_action(vif);
1614
1615 return IRQ_HANDLED;
1616}
1617
1618static int __init netback_init(void)
1619{
1620 int rc = 0;
1621
1622 if (!xen_domain())
1623 return -ENODEV;
1624
1625 /* Allow as many queues as there are CPUs if user has not
1626 * specified a value.
1627 */
1628 if (xenvif_max_queues == 0)
1629 xenvif_max_queues = num_online_cpus();
1630
1631 if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
1632 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
1633 fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
1634 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
1635 }
1636
1637 rc = xenvif_xenbus_init();
1638 if (rc)
1639 goto failed_init;
1640
1641#ifdef CONFIG_DEBUG_FS
1642 xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
1643 if (IS_ERR_OR_NULL(xen_netback_dbg_root))
1644 pr_warn("Init of debugfs returned %ld!\n",
1645 PTR_ERR(xen_netback_dbg_root));
1646#endif /* CONFIG_DEBUG_FS */
1647
1648 return 0;
1649
1650failed_init:
1651 return rc;
1652}
1653
1654module_init(netback_init);
1655
1656static void __exit netback_fini(void)
1657{
1658#ifdef CONFIG_DEBUG_FS
1659 if (!IS_ERR_OR_NULL(xen_netback_dbg_root))
1660 debugfs_remove_recursive(xen_netback_dbg_root);
1661#endif /* CONFIG_DEBUG_FS */
1662 xenvif_xenbus_fini();
1663}
1664module_exit(netback_fini);
1665
1666MODULE_LICENSE("Dual BSD/GPL");
1667MODULE_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/* Discriminate from any valid pending_idx value. */
64#define INVALID_PENDING_IDX 0xFFFF
65
66#define MAX_BUFFER_OFFSET PAGE_SIZE
67
68/* extra field used in struct page */
69union page_ext {
70 struct {
71#if BITS_PER_LONG < 64
72#define IDX_WIDTH 8
73#define GROUP_WIDTH (BITS_PER_LONG - IDX_WIDTH)
74 unsigned int group:GROUP_WIDTH;
75 unsigned int idx:IDX_WIDTH;
76#else
77 unsigned int group, idx;
78#endif
79 } e;
80 void *mapping;
81};
82
83struct xen_netbk {
84 wait_queue_head_t wq;
85 struct task_struct *task;
86
87 struct sk_buff_head rx_queue;
88 struct sk_buff_head tx_queue;
89
90 struct timer_list net_timer;
91
92 struct page *mmap_pages[MAX_PENDING_REQS];
93
94 pending_ring_idx_t pending_prod;
95 pending_ring_idx_t pending_cons;
96 struct list_head net_schedule_list;
97
98 /* Protect the net_schedule_list in netif. */
99 spinlock_t net_schedule_list_lock;
100
101 atomic_t netfront_count;
102
103 struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
104 struct gnttab_copy tx_copy_ops[MAX_PENDING_REQS];
105
106 u16 pending_ring[MAX_PENDING_REQS];
107
108 /*
109 * Given MAX_BUFFER_OFFSET of 4096 the worst case is that each
110 * head/fragment page uses 2 copy operations because it
111 * straddles two buffers in the frontend.
112 */
113 struct gnttab_copy grant_copy_op[2*XEN_NETIF_RX_RING_SIZE];
114 struct netbk_rx_meta meta[2*XEN_NETIF_RX_RING_SIZE];
115};
116
117static struct xen_netbk *xen_netbk;
118static int xen_netbk_group_nr;
119
120void xen_netbk_add_xenvif(struct xenvif *vif)
121{
122 int i;
123 int min_netfront_count;
124 int min_group = 0;
125 struct xen_netbk *netbk;
126
127 min_netfront_count = atomic_read(&xen_netbk[0].netfront_count);
128 for (i = 0; i < xen_netbk_group_nr; i++) {
129 int netfront_count = atomic_read(&xen_netbk[i].netfront_count);
130 if (netfront_count < min_netfront_count) {
131 min_group = i;
132 min_netfront_count = netfront_count;
133 }
134 }
135
136 netbk = &xen_netbk[min_group];
137
138 vif->netbk = netbk;
139 atomic_inc(&netbk->netfront_count);
140}
141
142void xen_netbk_remove_xenvif(struct xenvif *vif)
143{
144 struct xen_netbk *netbk = vif->netbk;
145 vif->netbk = NULL;
146 atomic_dec(&netbk->netfront_count);
147}
148
149static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx);
150static void make_tx_response(struct xenvif *vif,
151 struct xen_netif_tx_request *txp,
152 s8 st);
153static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
154 u16 id,
155 s8 st,
156 u16 offset,
157 u16 size,
158 u16 flags);
159
160static inline unsigned long idx_to_pfn(struct xen_netbk *netbk,
161 u16 idx)
162{
163 return page_to_pfn(netbk->mmap_pages[idx]);
164}
165
166static inline unsigned long idx_to_kaddr(struct xen_netbk *netbk,
167 u16 idx)
168{
169 return (unsigned long)pfn_to_kaddr(idx_to_pfn(netbk, idx));
170}
171
172/* extra field used in struct page */
173static inline void set_page_ext(struct page *pg, struct xen_netbk *netbk,
174 unsigned int idx)
175{
176 unsigned int group = netbk - xen_netbk;
177 union page_ext ext = { .e = { .group = group + 1, .idx = idx } };
178
179 BUILD_BUG_ON(sizeof(ext) > sizeof(ext.mapping));
180 pg->mapping = ext.mapping;
181}
182
183static int get_page_ext(struct page *pg,
184 unsigned int *pgroup, unsigned int *pidx)
185{
186 union page_ext ext = { .mapping = pg->mapping };
187 struct xen_netbk *netbk;
188 unsigned int group, idx;
189
190 group = ext.e.group - 1;
191
192 if (group < 0 || group >= xen_netbk_group_nr)
193 return 0;
194
195 netbk = &xen_netbk[group];
196
197 idx = ext.e.idx;
198
199 if ((idx < 0) || (idx >= MAX_PENDING_REQS))
200 return 0;
201
202 if (netbk->mmap_pages[idx] != pg)
203 return 0;
204
205 *pgroup = group;
206 *pidx = idx;
207
208 return 1;
209}
210
211/*
212 * This is the amount of packet we copy rather than map, so that the
213 * guest can't fiddle with the contents of the headers while we do
214 * packet processing on them (netfilter, routing, etc).
215 */
216#define PKT_PROT_LEN (ETH_HLEN + \
217 VLAN_HLEN + \
218 sizeof(struct iphdr) + MAX_IPOPTLEN + \
219 sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE)
220
221static u16 frag_get_pending_idx(skb_frag_t *frag)
222{
223 return (u16)frag->page_offset;
224}
225
226static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
227{
228 frag->page_offset = pending_idx;
229}
230
231static inline pending_ring_idx_t pending_index(unsigned i)
232{
233 return i & (MAX_PENDING_REQS-1);
234}
235
236static inline pending_ring_idx_t nr_pending_reqs(struct xen_netbk *netbk)
237{
238 return MAX_PENDING_REQS -
239 netbk->pending_prod + netbk->pending_cons;
240}
241
242static void xen_netbk_kick_thread(struct xen_netbk *netbk)
243{
244 wake_up(&netbk->wq);
245}
246
247static int max_required_rx_slots(struct xenvif *vif)
248{
249 int max = DIV_ROUND_UP(vif->dev->mtu, PAGE_SIZE);
250
251 if (vif->can_sg || vif->gso || vif->gso_prefix)
252 max += MAX_SKB_FRAGS + 1; /* extra_info + frags */
253
254 return max;
255}
256
257int xen_netbk_rx_ring_full(struct xenvif *vif)
258{
259 RING_IDX peek = vif->rx_req_cons_peek;
260 RING_IDX needed = max_required_rx_slots(vif);
261
262 return ((vif->rx.sring->req_prod - peek) < needed) ||
263 ((vif->rx.rsp_prod_pvt + XEN_NETIF_RX_RING_SIZE - peek) < needed);
264}
265
266int xen_netbk_must_stop_queue(struct xenvif *vif)
267{
268 if (!xen_netbk_rx_ring_full(vif))
269 return 0;
270
271 vif->rx.sring->req_event = vif->rx_req_cons_peek +
272 max_required_rx_slots(vif);
273 mb(); /* request notification /then/ check the queue */
274
275 return xen_netbk_rx_ring_full(vif);
276}
277
278/*
279 * Returns true if we should start a new receive buffer instead of
280 * adding 'size' bytes to a buffer which currently contains 'offset'
281 * bytes.
282 */
283static bool start_new_rx_buffer(int offset, unsigned long size, int head)
284{
285 /* simple case: we have completely filled the current buffer. */
286 if (offset == MAX_BUFFER_OFFSET)
287 return true;
288
289 /*
290 * complex case: start a fresh buffer if the current frag
291 * would overflow the current buffer but only if:
292 * (i) this frag would fit completely in the next buffer
293 * and (ii) there is already some data in the current buffer
294 * and (iii) this is not the head buffer.
295 *
296 * Where:
297 * - (i) stops us splitting a frag into two copies
298 * unless the frag is too large for a single buffer.
299 * - (ii) stops us from leaving a buffer pointlessly empty.
300 * - (iii) stops us leaving the first buffer
301 * empty. Strictly speaking this is already covered
302 * by (ii) but is explicitly checked because
303 * netfront relies on the first buffer being
304 * non-empty and can crash otherwise.
305 *
306 * This means we will effectively linearise small
307 * frags but do not needlessly split large buffers
308 * into multiple copies tend to give large frags their
309 * own buffers as before.
310 */
311 if ((offset + size > MAX_BUFFER_OFFSET) &&
312 (size <= MAX_BUFFER_OFFSET) && offset && !head)
313 return true;
314
315 return false;
316}
317
318/*
319 * Figure out how many ring slots we're going to need to send @skb to
320 * the guest. This function is essentially a dry run of
321 * netbk_gop_frag_copy.
322 */
323unsigned int xen_netbk_count_skb_slots(struct xenvif *vif, struct sk_buff *skb)
324{
325 unsigned int count;
326 int i, copy_off;
327
328 count = DIV_ROUND_UP(skb_headlen(skb), PAGE_SIZE);
329
330 copy_off = skb_headlen(skb) % PAGE_SIZE;
331
332 if (skb_shinfo(skb)->gso_size)
333 count++;
334
335 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
336 unsigned long size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
337 unsigned long bytes;
338 while (size > 0) {
339 BUG_ON(copy_off > MAX_BUFFER_OFFSET);
340
341 if (start_new_rx_buffer(copy_off, size, 0)) {
342 count++;
343 copy_off = 0;
344 }
345
346 bytes = size;
347 if (copy_off + bytes > MAX_BUFFER_OFFSET)
348 bytes = MAX_BUFFER_OFFSET - copy_off;
349
350 copy_off += bytes;
351 size -= bytes;
352 }
353 }
354 return count;
355}
356
357struct netrx_pending_operations {
358 unsigned copy_prod, copy_cons;
359 unsigned meta_prod, meta_cons;
360 struct gnttab_copy *copy;
361 struct netbk_rx_meta *meta;
362 int copy_off;
363 grant_ref_t copy_gref;
364};
365
366static struct netbk_rx_meta *get_next_rx_buffer(struct xenvif *vif,
367 struct netrx_pending_operations *npo)
368{
369 struct netbk_rx_meta *meta;
370 struct xen_netif_rx_request *req;
371
372 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
373
374 meta = npo->meta + npo->meta_prod++;
375 meta->gso_size = 0;
376 meta->size = 0;
377 meta->id = req->id;
378
379 npo->copy_off = 0;
380 npo->copy_gref = req->gref;
381
382 return meta;
383}
384
385/*
386 * Set up the grant operations for this fragment. If it's a flipping
387 * interface, we also set up the unmap request from here.
388 */
389static void netbk_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb,
390 struct netrx_pending_operations *npo,
391 struct page *page, unsigned long size,
392 unsigned long offset, int *head)
393{
394 struct gnttab_copy *copy_gop;
395 struct netbk_rx_meta *meta;
396 /*
397 * These variables are used iff get_page_ext returns true,
398 * in which case they are guaranteed to be initialized.
399 */
400 unsigned int uninitialized_var(group), uninitialized_var(idx);
401 int foreign = get_page_ext(page, &group, &idx);
402 unsigned long bytes;
403
404 /* Data must not cross a page boundary. */
405 BUG_ON(size + offset > PAGE_SIZE);
406
407 meta = npo->meta + npo->meta_prod - 1;
408
409 while (size > 0) {
410 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
411
412 if (start_new_rx_buffer(npo->copy_off, size, *head)) {
413 /*
414 * Netfront requires there to be some data in the head
415 * buffer.
416 */
417 BUG_ON(*head);
418
419 meta = get_next_rx_buffer(vif, npo);
420 }
421
422 bytes = size;
423 if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
424 bytes = MAX_BUFFER_OFFSET - npo->copy_off;
425
426 copy_gop = npo->copy + npo->copy_prod++;
427 copy_gop->flags = GNTCOPY_dest_gref;
428 if (foreign) {
429 struct xen_netbk *netbk = &xen_netbk[group];
430 struct pending_tx_info *src_pend;
431
432 src_pend = &netbk->pending_tx_info[idx];
433
434 copy_gop->source.domid = src_pend->vif->domid;
435 copy_gop->source.u.ref = src_pend->req.gref;
436 copy_gop->flags |= GNTCOPY_source_gref;
437 } else {
438 void *vaddr = page_address(page);
439 copy_gop->source.domid = DOMID_SELF;
440 copy_gop->source.u.gmfn = virt_to_mfn(vaddr);
441 }
442 copy_gop->source.offset = offset;
443 copy_gop->dest.domid = vif->domid;
444
445 copy_gop->dest.offset = npo->copy_off;
446 copy_gop->dest.u.ref = npo->copy_gref;
447 copy_gop->len = bytes;
448
449 npo->copy_off += bytes;
450 meta->size += bytes;
451
452 offset += bytes;
453 size -= bytes;
454
455 /* Leave a gap for the GSO descriptor. */
456 if (*head && skb_shinfo(skb)->gso_size && !vif->gso_prefix)
457 vif->rx.req_cons++;
458
459 *head = 0; /* There must be something in this buffer now. */
460
461 }
462}
463
464/*
465 * Prepare an SKB to be transmitted to the frontend.
466 *
467 * This function is responsible for allocating grant operations, meta
468 * structures, etc.
469 *
470 * It returns the number of meta structures consumed. The number of
471 * ring slots used is always equal to the number of meta slots used
472 * plus the number of GSO descriptors used. Currently, we use either
473 * zero GSO descriptors (for non-GSO packets) or one descriptor (for
474 * frontend-side LRO).
475 */
476static int netbk_gop_skb(struct sk_buff *skb,
477 struct netrx_pending_operations *npo)
478{
479 struct xenvif *vif = netdev_priv(skb->dev);
480 int nr_frags = skb_shinfo(skb)->nr_frags;
481 int i;
482 struct xen_netif_rx_request *req;
483 struct netbk_rx_meta *meta;
484 unsigned char *data;
485 int head = 1;
486 int old_meta_prod;
487
488 old_meta_prod = npo->meta_prod;
489
490 /* Set up a GSO prefix descriptor, if necessary */
491 if (skb_shinfo(skb)->gso_size && vif->gso_prefix) {
492 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
493 meta = npo->meta + npo->meta_prod++;
494 meta->gso_size = skb_shinfo(skb)->gso_size;
495 meta->size = 0;
496 meta->id = req->id;
497 }
498
499 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
500 meta = npo->meta + npo->meta_prod++;
501
502 if (!vif->gso_prefix)
503 meta->gso_size = skb_shinfo(skb)->gso_size;
504 else
505 meta->gso_size = 0;
506
507 meta->size = 0;
508 meta->id = req->id;
509 npo->copy_off = 0;
510 npo->copy_gref = req->gref;
511
512 data = skb->data;
513 while (data < skb_tail_pointer(skb)) {
514 unsigned int offset = offset_in_page(data);
515 unsigned int len = PAGE_SIZE - offset;
516
517 if (data + len > skb_tail_pointer(skb))
518 len = skb_tail_pointer(skb) - data;
519
520 netbk_gop_frag_copy(vif, skb, npo,
521 virt_to_page(data), len, offset, &head);
522 data += len;
523 }
524
525 for (i = 0; i < nr_frags; i++) {
526 netbk_gop_frag_copy(vif, skb, npo,
527 skb_frag_page(&skb_shinfo(skb)->frags[i]),
528 skb_frag_size(&skb_shinfo(skb)->frags[i]),
529 skb_shinfo(skb)->frags[i].page_offset,
530 &head);
531 }
532
533 return npo->meta_prod - old_meta_prod;
534}
535
536/*
537 * This is a twin to netbk_gop_skb. Assume that netbk_gop_skb was
538 * used to set up the operations on the top of
539 * netrx_pending_operations, which have since been done. Check that
540 * they didn't give any errors and advance over them.
541 */
542static int netbk_check_gop(struct xenvif *vif, int nr_meta_slots,
543 struct netrx_pending_operations *npo)
544{
545 struct gnttab_copy *copy_op;
546 int status = XEN_NETIF_RSP_OKAY;
547 int i;
548
549 for (i = 0; i < nr_meta_slots; i++) {
550 copy_op = npo->copy + npo->copy_cons++;
551 if (copy_op->status != GNTST_okay) {
552 netdev_dbg(vif->dev,
553 "Bad status %d from copy to DOM%d.\n",
554 copy_op->status, vif->domid);
555 status = XEN_NETIF_RSP_ERROR;
556 }
557 }
558
559 return status;
560}
561
562static void netbk_add_frag_responses(struct xenvif *vif, int status,
563 struct netbk_rx_meta *meta,
564 int nr_meta_slots)
565{
566 int i;
567 unsigned long offset;
568
569 /* No fragments used */
570 if (nr_meta_slots <= 1)
571 return;
572
573 nr_meta_slots--;
574
575 for (i = 0; i < nr_meta_slots; i++) {
576 int flags;
577 if (i == nr_meta_slots - 1)
578 flags = 0;
579 else
580 flags = XEN_NETRXF_more_data;
581
582 offset = 0;
583 make_rx_response(vif, meta[i].id, status, offset,
584 meta[i].size, flags);
585 }
586}
587
588struct skb_cb_overlay {
589 int meta_slots_used;
590};
591
592static void xen_netbk_rx_action(struct xen_netbk *netbk)
593{
594 struct xenvif *vif = NULL, *tmp;
595 s8 status;
596 u16 irq, flags;
597 struct xen_netif_rx_response *resp;
598 struct sk_buff_head rxq;
599 struct sk_buff *skb;
600 LIST_HEAD(notify);
601 int ret;
602 int nr_frags;
603 int count;
604 unsigned long offset;
605 struct skb_cb_overlay *sco;
606
607 struct netrx_pending_operations npo = {
608 .copy = netbk->grant_copy_op,
609 .meta = netbk->meta,
610 };
611
612 skb_queue_head_init(&rxq);
613
614 count = 0;
615
616 while ((skb = skb_dequeue(&netbk->rx_queue)) != NULL) {
617 vif = netdev_priv(skb->dev);
618 nr_frags = skb_shinfo(skb)->nr_frags;
619
620 sco = (struct skb_cb_overlay *)skb->cb;
621 sco->meta_slots_used = netbk_gop_skb(skb, &npo);
622
623 count += nr_frags + 1;
624
625 __skb_queue_tail(&rxq, skb);
626
627 /* Filled the batch queue? */
628 if (count + MAX_SKB_FRAGS >= XEN_NETIF_RX_RING_SIZE)
629 break;
630 }
631
632 BUG_ON(npo.meta_prod > ARRAY_SIZE(netbk->meta));
633
634 if (!npo.copy_prod)
635 return;
636
637 BUG_ON(npo.copy_prod > ARRAY_SIZE(netbk->grant_copy_op));
638 ret = HYPERVISOR_grant_table_op(GNTTABOP_copy, &netbk->grant_copy_op,
639 npo.copy_prod);
640 BUG_ON(ret != 0);
641
642 while ((skb = __skb_dequeue(&rxq)) != NULL) {
643 sco = (struct skb_cb_overlay *)skb->cb;
644
645 vif = netdev_priv(skb->dev);
646
647 if (netbk->meta[npo.meta_cons].gso_size && vif->gso_prefix) {
648 resp = RING_GET_RESPONSE(&vif->rx,
649 vif->rx.rsp_prod_pvt++);
650
651 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
652
653 resp->offset = netbk->meta[npo.meta_cons].gso_size;
654 resp->id = netbk->meta[npo.meta_cons].id;
655 resp->status = sco->meta_slots_used;
656
657 npo.meta_cons++;
658 sco->meta_slots_used--;
659 }
660
661
662 vif->dev->stats.tx_bytes += skb->len;
663 vif->dev->stats.tx_packets++;
664
665 status = netbk_check_gop(vif, sco->meta_slots_used, &npo);
666
667 if (sco->meta_slots_used == 1)
668 flags = 0;
669 else
670 flags = XEN_NETRXF_more_data;
671
672 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
673 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
674 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
675 /* remote but checksummed. */
676 flags |= XEN_NETRXF_data_validated;
677
678 offset = 0;
679 resp = make_rx_response(vif, netbk->meta[npo.meta_cons].id,
680 status, offset,
681 netbk->meta[npo.meta_cons].size,
682 flags);
683
684 if (netbk->meta[npo.meta_cons].gso_size && !vif->gso_prefix) {
685 struct xen_netif_extra_info *gso =
686 (struct xen_netif_extra_info *)
687 RING_GET_RESPONSE(&vif->rx,
688 vif->rx.rsp_prod_pvt++);
689
690 resp->flags |= XEN_NETRXF_extra_info;
691
692 gso->u.gso.size = netbk->meta[npo.meta_cons].gso_size;
693 gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
694 gso->u.gso.pad = 0;
695 gso->u.gso.features = 0;
696
697 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
698 gso->flags = 0;
699 }
700
701 netbk_add_frag_responses(vif, status,
702 netbk->meta + npo.meta_cons + 1,
703 sco->meta_slots_used);
704
705 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret);
706 irq = vif->irq;
707 if (ret && list_empty(&vif->notify_list))
708 list_add_tail(&vif->notify_list, ¬ify);
709
710 xenvif_notify_tx_completion(vif);
711
712 xenvif_put(vif);
713 npo.meta_cons += sco->meta_slots_used;
714 dev_kfree_skb(skb);
715 }
716
717 list_for_each_entry_safe(vif, tmp, ¬ify, notify_list) {
718 notify_remote_via_irq(vif->irq);
719 list_del_init(&vif->notify_list);
720 }
721
722 /* More work to do? */
723 if (!skb_queue_empty(&netbk->rx_queue) &&
724 !timer_pending(&netbk->net_timer))
725 xen_netbk_kick_thread(netbk);
726}
727
728void xen_netbk_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb)
729{
730 struct xen_netbk *netbk = vif->netbk;
731
732 skb_queue_tail(&netbk->rx_queue, skb);
733
734 xen_netbk_kick_thread(netbk);
735}
736
737static void xen_netbk_alarm(unsigned long data)
738{
739 struct xen_netbk *netbk = (struct xen_netbk *)data;
740 xen_netbk_kick_thread(netbk);
741}
742
743static int __on_net_schedule_list(struct xenvif *vif)
744{
745 return !list_empty(&vif->schedule_list);
746}
747
748/* Must be called with net_schedule_list_lock held */
749static void remove_from_net_schedule_list(struct xenvif *vif)
750{
751 if (likely(__on_net_schedule_list(vif))) {
752 list_del_init(&vif->schedule_list);
753 xenvif_put(vif);
754 }
755}
756
757static struct xenvif *poll_net_schedule_list(struct xen_netbk *netbk)
758{
759 struct xenvif *vif = NULL;
760
761 spin_lock_irq(&netbk->net_schedule_list_lock);
762 if (list_empty(&netbk->net_schedule_list))
763 goto out;
764
765 vif = list_first_entry(&netbk->net_schedule_list,
766 struct xenvif, schedule_list);
767 if (!vif)
768 goto out;
769
770 xenvif_get(vif);
771
772 remove_from_net_schedule_list(vif);
773out:
774 spin_unlock_irq(&netbk->net_schedule_list_lock);
775 return vif;
776}
777
778void xen_netbk_schedule_xenvif(struct xenvif *vif)
779{
780 unsigned long flags;
781 struct xen_netbk *netbk = vif->netbk;
782
783 if (__on_net_schedule_list(vif))
784 goto kick;
785
786 spin_lock_irqsave(&netbk->net_schedule_list_lock, flags);
787 if (!__on_net_schedule_list(vif) &&
788 likely(xenvif_schedulable(vif))) {
789 list_add_tail(&vif->schedule_list, &netbk->net_schedule_list);
790 xenvif_get(vif);
791 }
792 spin_unlock_irqrestore(&netbk->net_schedule_list_lock, flags);
793
794kick:
795 smp_mb();
796 if ((nr_pending_reqs(netbk) < (MAX_PENDING_REQS/2)) &&
797 !list_empty(&netbk->net_schedule_list))
798 xen_netbk_kick_thread(netbk);
799}
800
801void xen_netbk_deschedule_xenvif(struct xenvif *vif)
802{
803 struct xen_netbk *netbk = vif->netbk;
804 spin_lock_irq(&netbk->net_schedule_list_lock);
805 remove_from_net_schedule_list(vif);
806 spin_unlock_irq(&netbk->net_schedule_list_lock);
807}
808
809void xen_netbk_check_rx_xenvif(struct xenvif *vif)
810{
811 int more_to_do;
812
813 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
814
815 if (more_to_do)
816 xen_netbk_schedule_xenvif(vif);
817}
818
819static void tx_add_credit(struct xenvif *vif)
820{
821 unsigned long max_burst, max_credit;
822
823 /*
824 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
825 * Otherwise the interface can seize up due to insufficient credit.
826 */
827 max_burst = RING_GET_REQUEST(&vif->tx, vif->tx.req_cons)->size;
828 max_burst = min(max_burst, 131072UL);
829 max_burst = max(max_burst, vif->credit_bytes);
830
831 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
832 max_credit = vif->remaining_credit + vif->credit_bytes;
833 if (max_credit < vif->remaining_credit)
834 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
835
836 vif->remaining_credit = min(max_credit, max_burst);
837}
838
839static void tx_credit_callback(unsigned long data)
840{
841 struct xenvif *vif = (struct xenvif *)data;
842 tx_add_credit(vif);
843 xen_netbk_check_rx_xenvif(vif);
844}
845
846static void netbk_tx_err(struct xenvif *vif,
847 struct xen_netif_tx_request *txp, RING_IDX end)
848{
849 RING_IDX cons = vif->tx.req_cons;
850
851 do {
852 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
853 if (cons >= end)
854 break;
855 txp = RING_GET_REQUEST(&vif->tx, cons++);
856 } while (1);
857 vif->tx.req_cons = cons;
858 xen_netbk_check_rx_xenvif(vif);
859 xenvif_put(vif);
860}
861
862static int netbk_count_requests(struct xenvif *vif,
863 struct xen_netif_tx_request *first,
864 struct xen_netif_tx_request *txp,
865 int work_to_do)
866{
867 RING_IDX cons = vif->tx.req_cons;
868 int frags = 0;
869
870 if (!(first->flags & XEN_NETTXF_more_data))
871 return 0;
872
873 do {
874 if (frags >= work_to_do) {
875 netdev_dbg(vif->dev, "Need more frags\n");
876 return -frags;
877 }
878
879 if (unlikely(frags >= MAX_SKB_FRAGS)) {
880 netdev_dbg(vif->dev, "Too many frags\n");
881 return -frags;
882 }
883
884 memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + frags),
885 sizeof(*txp));
886 if (txp->size > first->size) {
887 netdev_dbg(vif->dev, "Frags galore\n");
888 return -frags;
889 }
890
891 first->size -= txp->size;
892 frags++;
893
894 if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
895 netdev_dbg(vif->dev, "txp->offset: %x, size: %u\n",
896 txp->offset, txp->size);
897 return -frags;
898 }
899 } while ((txp++)->flags & XEN_NETTXF_more_data);
900 return frags;
901}
902
903static struct page *xen_netbk_alloc_page(struct xen_netbk *netbk,
904 struct sk_buff *skb,
905 u16 pending_idx)
906{
907 struct page *page;
908 page = alloc_page(GFP_KERNEL|__GFP_COLD);
909 if (!page)
910 return NULL;
911 set_page_ext(page, netbk, pending_idx);
912 netbk->mmap_pages[pending_idx] = page;
913 return page;
914}
915
916static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
917 struct xenvif *vif,
918 struct sk_buff *skb,
919 struct xen_netif_tx_request *txp,
920 struct gnttab_copy *gop)
921{
922 struct skb_shared_info *shinfo = skb_shinfo(skb);
923 skb_frag_t *frags = shinfo->frags;
924 u16 pending_idx = *((u16 *)skb->data);
925 int i, start;
926
927 /* Skip first skb fragment if it is on same page as header fragment. */
928 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
929
930 for (i = start; i < shinfo->nr_frags; i++, txp++) {
931 struct page *page;
932 pending_ring_idx_t index;
933 struct pending_tx_info *pending_tx_info =
934 netbk->pending_tx_info;
935
936 index = pending_index(netbk->pending_cons++);
937 pending_idx = netbk->pending_ring[index];
938 page = xen_netbk_alloc_page(netbk, skb, pending_idx);
939 if (!page)
940 return NULL;
941
942 gop->source.u.ref = txp->gref;
943 gop->source.domid = vif->domid;
944 gop->source.offset = txp->offset;
945
946 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
947 gop->dest.domid = DOMID_SELF;
948 gop->dest.offset = txp->offset;
949
950 gop->len = txp->size;
951 gop->flags = GNTCOPY_source_gref;
952
953 gop++;
954
955 memcpy(&pending_tx_info[pending_idx].req, txp, sizeof(*txp));
956 xenvif_get(vif);
957 pending_tx_info[pending_idx].vif = vif;
958 frag_set_pending_idx(&frags[i], pending_idx);
959 }
960
961 return gop;
962}
963
964static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
965 struct sk_buff *skb,
966 struct gnttab_copy **gopp)
967{
968 struct gnttab_copy *gop = *gopp;
969 u16 pending_idx = *((u16 *)skb->data);
970 struct pending_tx_info *pending_tx_info = netbk->pending_tx_info;
971 struct xenvif *vif = pending_tx_info[pending_idx].vif;
972 struct xen_netif_tx_request *txp;
973 struct skb_shared_info *shinfo = skb_shinfo(skb);
974 int nr_frags = shinfo->nr_frags;
975 int i, err, start;
976
977 /* Check status of header. */
978 err = gop->status;
979 if (unlikely(err)) {
980 pending_ring_idx_t index;
981 index = pending_index(netbk->pending_prod++);
982 txp = &pending_tx_info[pending_idx].req;
983 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
984 netbk->pending_ring[index] = pending_idx;
985 xenvif_put(vif);
986 }
987
988 /* Skip first skb fragment if it is on same page as header fragment. */
989 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
990
991 for (i = start; i < nr_frags; i++) {
992 int j, newerr;
993 pending_ring_idx_t index;
994
995 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
996
997 /* Check error status: if okay then remember grant handle. */
998 newerr = (++gop)->status;
999 if (likely(!newerr)) {
1000 /* Had a previous error? Invalidate this fragment. */
1001 if (unlikely(err))
1002 xen_netbk_idx_release(netbk, pending_idx);
1003 continue;
1004 }
1005
1006 /* Error on this fragment: respond to client with an error. */
1007 txp = &netbk->pending_tx_info[pending_idx].req;
1008 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
1009 index = pending_index(netbk->pending_prod++);
1010 netbk->pending_ring[index] = pending_idx;
1011 xenvif_put(vif);
1012
1013 /* Not the first error? Preceding frags already invalidated. */
1014 if (err)
1015 continue;
1016
1017 /* First error: invalidate header and preceding fragments. */
1018 pending_idx = *((u16 *)skb->data);
1019 xen_netbk_idx_release(netbk, pending_idx);
1020 for (j = start; j < i; j++) {
1021 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
1022 xen_netbk_idx_release(netbk, pending_idx);
1023 }
1024
1025 /* Remember the error: invalidate all subsequent fragments. */
1026 err = newerr;
1027 }
1028
1029 *gopp = gop + 1;
1030 return err;
1031}
1032
1033static void xen_netbk_fill_frags(struct xen_netbk *netbk, struct sk_buff *skb)
1034{
1035 struct skb_shared_info *shinfo = skb_shinfo(skb);
1036 int nr_frags = shinfo->nr_frags;
1037 int i;
1038
1039 for (i = 0; i < nr_frags; i++) {
1040 skb_frag_t *frag = shinfo->frags + i;
1041 struct xen_netif_tx_request *txp;
1042 struct page *page;
1043 u16 pending_idx;
1044
1045 pending_idx = frag_get_pending_idx(frag);
1046
1047 txp = &netbk->pending_tx_info[pending_idx].req;
1048 page = virt_to_page(idx_to_kaddr(netbk, pending_idx));
1049 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
1050 skb->len += txp->size;
1051 skb->data_len += txp->size;
1052 skb->truesize += txp->size;
1053
1054 /* Take an extra reference to offset xen_netbk_idx_release */
1055 get_page(netbk->mmap_pages[pending_idx]);
1056 xen_netbk_idx_release(netbk, pending_idx);
1057 }
1058}
1059
1060static int xen_netbk_get_extras(struct xenvif *vif,
1061 struct xen_netif_extra_info *extras,
1062 int work_to_do)
1063{
1064 struct xen_netif_extra_info extra;
1065 RING_IDX cons = vif->tx.req_cons;
1066
1067 do {
1068 if (unlikely(work_to_do-- <= 0)) {
1069 netdev_dbg(vif->dev, "Missing extra info\n");
1070 return -EBADR;
1071 }
1072
1073 memcpy(&extra, RING_GET_REQUEST(&vif->tx, cons),
1074 sizeof(extra));
1075 if (unlikely(!extra.type ||
1076 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1077 vif->tx.req_cons = ++cons;
1078 netdev_dbg(vif->dev,
1079 "Invalid extra type: %d\n", extra.type);
1080 return -EINVAL;
1081 }
1082
1083 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1084 vif->tx.req_cons = ++cons;
1085 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1086
1087 return work_to_do;
1088}
1089
1090static int netbk_set_skb_gso(struct xenvif *vif,
1091 struct sk_buff *skb,
1092 struct xen_netif_extra_info *gso)
1093{
1094 if (!gso->u.gso.size) {
1095 netdev_dbg(vif->dev, "GSO size must not be zero.\n");
1096 return -EINVAL;
1097 }
1098
1099 /* Currently only TCPv4 S.O. is supported. */
1100 if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
1101 netdev_dbg(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1102 return -EINVAL;
1103 }
1104
1105 skb_shinfo(skb)->gso_size = gso->u.gso.size;
1106 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1107
1108 /* Header must be checked, and gso_segs computed. */
1109 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1110 skb_shinfo(skb)->gso_segs = 0;
1111
1112 return 0;
1113}
1114
1115static int checksum_setup(struct xenvif *vif, struct sk_buff *skb)
1116{
1117 struct iphdr *iph;
1118 unsigned char *th;
1119 int err = -EPROTO;
1120 int recalculate_partial_csum = 0;
1121
1122 /*
1123 * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1124 * peers can fail to set NETRXF_csum_blank when sending a GSO
1125 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1126 * recalculate the partial checksum.
1127 */
1128 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1129 vif->rx_gso_checksum_fixup++;
1130 skb->ip_summed = CHECKSUM_PARTIAL;
1131 recalculate_partial_csum = 1;
1132 }
1133
1134 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1135 if (skb->ip_summed != CHECKSUM_PARTIAL)
1136 return 0;
1137
1138 if (skb->protocol != htons(ETH_P_IP))
1139 goto out;
1140
1141 iph = (void *)skb->data;
1142 th = skb->data + 4 * iph->ihl;
1143 if (th >= skb_tail_pointer(skb))
1144 goto out;
1145
1146 skb->csum_start = th - skb->head;
1147 switch (iph->protocol) {
1148 case IPPROTO_TCP:
1149 skb->csum_offset = offsetof(struct tcphdr, check);
1150
1151 if (recalculate_partial_csum) {
1152 struct tcphdr *tcph = (struct tcphdr *)th;
1153 tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1154 skb->len - iph->ihl*4,
1155 IPPROTO_TCP, 0);
1156 }
1157 break;
1158 case IPPROTO_UDP:
1159 skb->csum_offset = offsetof(struct udphdr, check);
1160
1161 if (recalculate_partial_csum) {
1162 struct udphdr *udph = (struct udphdr *)th;
1163 udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1164 skb->len - iph->ihl*4,
1165 IPPROTO_UDP, 0);
1166 }
1167 break;
1168 default:
1169 if (net_ratelimit())
1170 netdev_err(vif->dev,
1171 "Attempting to checksum a non-TCP/UDP packet, dropping a protocol %d packet\n",
1172 iph->protocol);
1173 goto out;
1174 }
1175
1176 if ((th + skb->csum_offset + 2) > skb_tail_pointer(skb))
1177 goto out;
1178
1179 err = 0;
1180
1181out:
1182 return err;
1183}
1184
1185static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
1186{
1187 unsigned long now = jiffies;
1188 unsigned long next_credit =
1189 vif->credit_timeout.expires +
1190 msecs_to_jiffies(vif->credit_usec / 1000);
1191
1192 /* Timer could already be pending in rare cases. */
1193 if (timer_pending(&vif->credit_timeout))
1194 return true;
1195
1196 /* Passed the point where we can replenish credit? */
1197 if (time_after_eq(now, next_credit)) {
1198 vif->credit_timeout.expires = now;
1199 tx_add_credit(vif);
1200 }
1201
1202 /* Still too big to send right now? Set a callback. */
1203 if (size > vif->remaining_credit) {
1204 vif->credit_timeout.data =
1205 (unsigned long)vif;
1206 vif->credit_timeout.function =
1207 tx_credit_callback;
1208 mod_timer(&vif->credit_timeout,
1209 next_credit);
1210
1211 return true;
1212 }
1213
1214 return false;
1215}
1216
1217static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk)
1218{
1219 struct gnttab_copy *gop = netbk->tx_copy_ops, *request_gop;
1220 struct sk_buff *skb;
1221 int ret;
1222
1223 while (((nr_pending_reqs(netbk) + MAX_SKB_FRAGS) < MAX_PENDING_REQS) &&
1224 !list_empty(&netbk->net_schedule_list)) {
1225 struct xenvif *vif;
1226 struct xen_netif_tx_request txreq;
1227 struct xen_netif_tx_request txfrags[MAX_SKB_FRAGS];
1228 struct page *page;
1229 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
1230 u16 pending_idx;
1231 RING_IDX idx;
1232 int work_to_do;
1233 unsigned int data_len;
1234 pending_ring_idx_t index;
1235
1236 /* Get a netif from the list with work to do. */
1237 vif = poll_net_schedule_list(netbk);
1238 if (!vif)
1239 continue;
1240
1241 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, work_to_do);
1242 if (!work_to_do) {
1243 xenvif_put(vif);
1244 continue;
1245 }
1246
1247 idx = vif->tx.req_cons;
1248 rmb(); /* Ensure that we see the request before we copy it. */
1249 memcpy(&txreq, RING_GET_REQUEST(&vif->tx, idx), sizeof(txreq));
1250
1251 /* Credit-based scheduling. */
1252 if (txreq.size > vif->remaining_credit &&
1253 tx_credit_exceeded(vif, txreq.size)) {
1254 xenvif_put(vif);
1255 continue;
1256 }
1257
1258 vif->remaining_credit -= txreq.size;
1259
1260 work_to_do--;
1261 vif->tx.req_cons = ++idx;
1262
1263 memset(extras, 0, sizeof(extras));
1264 if (txreq.flags & XEN_NETTXF_extra_info) {
1265 work_to_do = xen_netbk_get_extras(vif, extras,
1266 work_to_do);
1267 idx = vif->tx.req_cons;
1268 if (unlikely(work_to_do < 0)) {
1269 netbk_tx_err(vif, &txreq, idx);
1270 continue;
1271 }
1272 }
1273
1274 ret = netbk_count_requests(vif, &txreq, txfrags, work_to_do);
1275 if (unlikely(ret < 0)) {
1276 netbk_tx_err(vif, &txreq, idx - ret);
1277 continue;
1278 }
1279 idx += ret;
1280
1281 if (unlikely(txreq.size < ETH_HLEN)) {
1282 netdev_dbg(vif->dev,
1283 "Bad packet size: %d\n", txreq.size);
1284 netbk_tx_err(vif, &txreq, idx);
1285 continue;
1286 }
1287
1288 /* No crossing a page as the payload mustn't fragment. */
1289 if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
1290 netdev_dbg(vif->dev,
1291 "txreq.offset: %x, size: %u, end: %lu\n",
1292 txreq.offset, txreq.size,
1293 (txreq.offset&~PAGE_MASK) + txreq.size);
1294 netbk_tx_err(vif, &txreq, idx);
1295 continue;
1296 }
1297
1298 index = pending_index(netbk->pending_cons);
1299 pending_idx = netbk->pending_ring[index];
1300
1301 data_len = (txreq.size > PKT_PROT_LEN &&
1302 ret < MAX_SKB_FRAGS) ?
1303 PKT_PROT_LEN : txreq.size;
1304
1305 skb = alloc_skb(data_len + NET_SKB_PAD + NET_IP_ALIGN,
1306 GFP_ATOMIC | __GFP_NOWARN);
1307 if (unlikely(skb == NULL)) {
1308 netdev_dbg(vif->dev,
1309 "Can't allocate a skb in start_xmit.\n");
1310 netbk_tx_err(vif, &txreq, idx);
1311 break;
1312 }
1313
1314 /* Packets passed to netif_rx() must have some headroom. */
1315 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
1316
1317 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1318 struct xen_netif_extra_info *gso;
1319 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1320
1321 if (netbk_set_skb_gso(vif, skb, gso)) {
1322 kfree_skb(skb);
1323 netbk_tx_err(vif, &txreq, idx);
1324 continue;
1325 }
1326 }
1327
1328 /* XXX could copy straight to head */
1329 page = xen_netbk_alloc_page(netbk, skb, pending_idx);
1330 if (!page) {
1331 kfree_skb(skb);
1332 netbk_tx_err(vif, &txreq, idx);
1333 continue;
1334 }
1335
1336 gop->source.u.ref = txreq.gref;
1337 gop->source.domid = vif->domid;
1338 gop->source.offset = txreq.offset;
1339
1340 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
1341 gop->dest.domid = DOMID_SELF;
1342 gop->dest.offset = txreq.offset;
1343
1344 gop->len = txreq.size;
1345 gop->flags = GNTCOPY_source_gref;
1346
1347 gop++;
1348
1349 memcpy(&netbk->pending_tx_info[pending_idx].req,
1350 &txreq, sizeof(txreq));
1351 netbk->pending_tx_info[pending_idx].vif = vif;
1352 *((u16 *)skb->data) = pending_idx;
1353
1354 __skb_put(skb, data_len);
1355
1356 skb_shinfo(skb)->nr_frags = ret;
1357 if (data_len < txreq.size) {
1358 skb_shinfo(skb)->nr_frags++;
1359 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1360 pending_idx);
1361 } else {
1362 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1363 INVALID_PENDING_IDX);
1364 }
1365
1366 __skb_queue_tail(&netbk->tx_queue, skb);
1367
1368 netbk->pending_cons++;
1369
1370 request_gop = xen_netbk_get_requests(netbk, vif,
1371 skb, txfrags, gop);
1372 if (request_gop == NULL) {
1373 kfree_skb(skb);
1374 netbk_tx_err(vif, &txreq, idx);
1375 continue;
1376 }
1377 gop = request_gop;
1378
1379 vif->tx.req_cons = idx;
1380 xen_netbk_check_rx_xenvif(vif);
1381
1382 if ((gop-netbk->tx_copy_ops) >= ARRAY_SIZE(netbk->tx_copy_ops))
1383 break;
1384 }
1385
1386 return gop - netbk->tx_copy_ops;
1387}
1388
1389static void xen_netbk_tx_submit(struct xen_netbk *netbk)
1390{
1391 struct gnttab_copy *gop = netbk->tx_copy_ops;
1392 struct sk_buff *skb;
1393
1394 while ((skb = __skb_dequeue(&netbk->tx_queue)) != NULL) {
1395 struct xen_netif_tx_request *txp;
1396 struct xenvif *vif;
1397 u16 pending_idx;
1398 unsigned data_len;
1399
1400 pending_idx = *((u16 *)skb->data);
1401 vif = netbk->pending_tx_info[pending_idx].vif;
1402 txp = &netbk->pending_tx_info[pending_idx].req;
1403
1404 /* Check the remap error code. */
1405 if (unlikely(xen_netbk_tx_check_gop(netbk, skb, &gop))) {
1406 netdev_dbg(vif->dev, "netback grant failed.\n");
1407 skb_shinfo(skb)->nr_frags = 0;
1408 kfree_skb(skb);
1409 continue;
1410 }
1411
1412 data_len = skb->len;
1413 memcpy(skb->data,
1414 (void *)(idx_to_kaddr(netbk, pending_idx)|txp->offset),
1415 data_len);
1416 if (data_len < txp->size) {
1417 /* Append the packet payload as a fragment. */
1418 txp->offset += data_len;
1419 txp->size -= data_len;
1420 } else {
1421 /* Schedule a response immediately. */
1422 xen_netbk_idx_release(netbk, pending_idx);
1423 }
1424
1425 if (txp->flags & XEN_NETTXF_csum_blank)
1426 skb->ip_summed = CHECKSUM_PARTIAL;
1427 else if (txp->flags & XEN_NETTXF_data_validated)
1428 skb->ip_summed = CHECKSUM_UNNECESSARY;
1429
1430 xen_netbk_fill_frags(netbk, skb);
1431
1432 /*
1433 * If the initial fragment was < PKT_PROT_LEN then
1434 * pull through some bytes from the other fragments to
1435 * increase the linear region to PKT_PROT_LEN bytes.
1436 */
1437 if (skb_headlen(skb) < PKT_PROT_LEN && skb_is_nonlinear(skb)) {
1438 int target = min_t(int, skb->len, PKT_PROT_LEN);
1439 __pskb_pull_tail(skb, target - skb_headlen(skb));
1440 }
1441
1442 skb->dev = vif->dev;
1443 skb->protocol = eth_type_trans(skb, skb->dev);
1444
1445 if (checksum_setup(vif, skb)) {
1446 netdev_dbg(vif->dev,
1447 "Can't setup checksum in net_tx_action\n");
1448 kfree_skb(skb);
1449 continue;
1450 }
1451
1452 vif->dev->stats.rx_bytes += skb->len;
1453 vif->dev->stats.rx_packets++;
1454
1455 xenvif_receive_skb(vif, skb);
1456 }
1457}
1458
1459/* Called after netfront has transmitted */
1460static void xen_netbk_tx_action(struct xen_netbk *netbk)
1461{
1462 unsigned nr_gops;
1463 int ret;
1464
1465 nr_gops = xen_netbk_tx_build_gops(netbk);
1466
1467 if (nr_gops == 0)
1468 return;
1469 ret = HYPERVISOR_grant_table_op(GNTTABOP_copy,
1470 netbk->tx_copy_ops, nr_gops);
1471 BUG_ON(ret);
1472
1473 xen_netbk_tx_submit(netbk);
1474
1475}
1476
1477static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx)
1478{
1479 struct xenvif *vif;
1480 struct pending_tx_info *pending_tx_info;
1481 pending_ring_idx_t index;
1482
1483 /* Already complete? */
1484 if (netbk->mmap_pages[pending_idx] == NULL)
1485 return;
1486
1487 pending_tx_info = &netbk->pending_tx_info[pending_idx];
1488
1489 vif = pending_tx_info->vif;
1490
1491 make_tx_response(vif, &pending_tx_info->req, XEN_NETIF_RSP_OKAY);
1492
1493 index = pending_index(netbk->pending_prod++);
1494 netbk->pending_ring[index] = pending_idx;
1495
1496 xenvif_put(vif);
1497
1498 netbk->mmap_pages[pending_idx]->mapping = 0;
1499 put_page(netbk->mmap_pages[pending_idx]);
1500 netbk->mmap_pages[pending_idx] = NULL;
1501}
1502
1503static void make_tx_response(struct xenvif *vif,
1504 struct xen_netif_tx_request *txp,
1505 s8 st)
1506{
1507 RING_IDX i = vif->tx.rsp_prod_pvt;
1508 struct xen_netif_tx_response *resp;
1509 int notify;
1510
1511 resp = RING_GET_RESPONSE(&vif->tx, i);
1512 resp->id = txp->id;
1513 resp->status = st;
1514
1515 if (txp->flags & XEN_NETTXF_extra_info)
1516 RING_GET_RESPONSE(&vif->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1517
1518 vif->tx.rsp_prod_pvt = ++i;
1519 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->tx, notify);
1520 if (notify)
1521 notify_remote_via_irq(vif->irq);
1522}
1523
1524static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
1525 u16 id,
1526 s8 st,
1527 u16 offset,
1528 u16 size,
1529 u16 flags)
1530{
1531 RING_IDX i = vif->rx.rsp_prod_pvt;
1532 struct xen_netif_rx_response *resp;
1533
1534 resp = RING_GET_RESPONSE(&vif->rx, i);
1535 resp->offset = offset;
1536 resp->flags = flags;
1537 resp->id = id;
1538 resp->status = (s16)size;
1539 if (st < 0)
1540 resp->status = (s16)st;
1541
1542 vif->rx.rsp_prod_pvt = ++i;
1543
1544 return resp;
1545}
1546
1547static inline int rx_work_todo(struct xen_netbk *netbk)
1548{
1549 return !skb_queue_empty(&netbk->rx_queue);
1550}
1551
1552static inline int tx_work_todo(struct xen_netbk *netbk)
1553{
1554
1555 if (((nr_pending_reqs(netbk) + MAX_SKB_FRAGS) < MAX_PENDING_REQS) &&
1556 !list_empty(&netbk->net_schedule_list))
1557 return 1;
1558
1559 return 0;
1560}
1561
1562static int xen_netbk_kthread(void *data)
1563{
1564 struct xen_netbk *netbk = data;
1565 while (!kthread_should_stop()) {
1566 wait_event_interruptible(netbk->wq,
1567 rx_work_todo(netbk) ||
1568 tx_work_todo(netbk) ||
1569 kthread_should_stop());
1570 cond_resched();
1571
1572 if (kthread_should_stop())
1573 break;
1574
1575 if (rx_work_todo(netbk))
1576 xen_netbk_rx_action(netbk);
1577
1578 if (tx_work_todo(netbk))
1579 xen_netbk_tx_action(netbk);
1580 }
1581
1582 return 0;
1583}
1584
1585void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
1586{
1587 if (vif->tx.sring)
1588 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1589 vif->tx.sring);
1590 if (vif->rx.sring)
1591 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1592 vif->rx.sring);
1593}
1594
1595int xen_netbk_map_frontend_rings(struct xenvif *vif,
1596 grant_ref_t tx_ring_ref,
1597 grant_ref_t rx_ring_ref)
1598{
1599 void *addr;
1600 struct xen_netif_tx_sring *txs;
1601 struct xen_netif_rx_sring *rxs;
1602
1603 int err = -ENOMEM;
1604
1605 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1606 tx_ring_ref, &addr);
1607 if (err)
1608 goto err;
1609
1610 txs = (struct xen_netif_tx_sring *)addr;
1611 BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
1612
1613 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1614 rx_ring_ref, &addr);
1615 if (err)
1616 goto err;
1617
1618 rxs = (struct xen_netif_rx_sring *)addr;
1619 BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
1620
1621 vif->rx_req_cons_peek = 0;
1622
1623 return 0;
1624
1625err:
1626 xen_netbk_unmap_frontend_rings(vif);
1627 return err;
1628}
1629
1630static int __init netback_init(void)
1631{
1632 int i;
1633 int rc = 0;
1634 int group;
1635
1636 if (!xen_domain())
1637 return -ENODEV;
1638
1639 xen_netbk_group_nr = num_online_cpus();
1640 xen_netbk = vzalloc(sizeof(struct xen_netbk) * xen_netbk_group_nr);
1641 if (!xen_netbk)
1642 return -ENOMEM;
1643
1644 for (group = 0; group < xen_netbk_group_nr; group++) {
1645 struct xen_netbk *netbk = &xen_netbk[group];
1646 skb_queue_head_init(&netbk->rx_queue);
1647 skb_queue_head_init(&netbk->tx_queue);
1648
1649 init_timer(&netbk->net_timer);
1650 netbk->net_timer.data = (unsigned long)netbk;
1651 netbk->net_timer.function = xen_netbk_alarm;
1652
1653 netbk->pending_cons = 0;
1654 netbk->pending_prod = MAX_PENDING_REQS;
1655 for (i = 0; i < MAX_PENDING_REQS; i++)
1656 netbk->pending_ring[i] = i;
1657
1658 init_waitqueue_head(&netbk->wq);
1659 netbk->task = kthread_create(xen_netbk_kthread,
1660 (void *)netbk,
1661 "netback/%u", group);
1662
1663 if (IS_ERR(netbk->task)) {
1664 printk(KERN_ALERT "kthread_create() fails at netback\n");
1665 del_timer(&netbk->net_timer);
1666 rc = PTR_ERR(netbk->task);
1667 goto failed_init;
1668 }
1669
1670 kthread_bind(netbk->task, group);
1671
1672 INIT_LIST_HEAD(&netbk->net_schedule_list);
1673
1674 spin_lock_init(&netbk->net_schedule_list_lock);
1675
1676 atomic_set(&netbk->netfront_count, 0);
1677
1678 wake_up_process(netbk->task);
1679 }
1680
1681 rc = xenvif_xenbus_init();
1682 if (rc)
1683 goto failed_init;
1684
1685 return 0;
1686
1687failed_init:
1688 while (--group >= 0) {
1689 struct xen_netbk *netbk = &xen_netbk[group];
1690 for (i = 0; i < MAX_PENDING_REQS; i++) {
1691 if (netbk->mmap_pages[i])
1692 __free_page(netbk->mmap_pages[i]);
1693 }
1694 del_timer(&netbk->net_timer);
1695 kthread_stop(netbk->task);
1696 }
1697 vfree(xen_netbk);
1698 return rc;
1699
1700}
1701
1702module_init(netback_init);
1703
1704MODULE_LICENSE("Dual BSD/GPL");
1705MODULE_ALIAS("xen-backend:vif");