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ftrace, sched: Add TRACE_FLAG_PREEMPT_RESCHED
[deliverable/linux.git] / drivers / net / xen-netback / netback.c
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/xen.h>
44 #include <xen/events.h>
45 #include <xen/interface/memory.h>
46
47 #include <asm/xen/hypercall.h>
48 #include <asm/xen/page.h>
49
50 /* Provide an option to disable split event channels at load time as
51 * event channels are limited resource. Split event channels are
52 * enabled by default.
53 */
54 bool separate_tx_rx_irq = 1;
55 module_param(separate_tx_rx_irq, bool, 0644);
56
57 /*
58 * This is the maximum slots a skb can have. If a guest sends a skb
59 * which exceeds this limit it is considered malicious.
60 */
61 #define FATAL_SKB_SLOTS_DEFAULT 20
62 static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
63 module_param(fatal_skb_slots, uint, 0444);
64
65 /*
66 * To avoid confusion, we define XEN_NETBK_LEGACY_SLOTS_MAX indicating
67 * the maximum slots a valid packet can use. Now this value is defined
68 * to be XEN_NETIF_NR_SLOTS_MIN, which is supposed to be supported by
69 * all backend.
70 */
71 #define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN
72
73 /*
74 * If head != INVALID_PENDING_RING_IDX, it means this tx request is head of
75 * one or more merged tx requests, otherwise it is the continuation of
76 * previous tx request.
77 */
78 static inline int pending_tx_is_head(struct xenvif *vif, RING_IDX idx)
79 {
80 return vif->pending_tx_info[idx].head != INVALID_PENDING_RING_IDX;
81 }
82
83 static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx,
84 u8 status);
85
86 static void make_tx_response(struct xenvif *vif,
87 struct xen_netif_tx_request *txp,
88 s8 st);
89
90 static inline int tx_work_todo(struct xenvif *vif);
91 static inline int rx_work_todo(struct xenvif *vif);
92
93 static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
94 u16 id,
95 s8 st,
96 u16 offset,
97 u16 size,
98 u16 flags);
99
100 static inline unsigned long idx_to_pfn(struct xenvif *vif,
101 u16 idx)
102 {
103 return page_to_pfn(vif->mmap_pages[idx]);
104 }
105
106 static inline unsigned long idx_to_kaddr(struct xenvif *vif,
107 u16 idx)
108 {
109 return (unsigned long)pfn_to_kaddr(idx_to_pfn(vif, idx));
110 }
111
112 /*
113 * This is the amount of packet we copy rather than map, so that the
114 * guest can't fiddle with the contents of the headers while we do
115 * packet processing on them (netfilter, routing, etc).
116 */
117 #define PKT_PROT_LEN (ETH_HLEN + \
118 VLAN_HLEN + \
119 sizeof(struct iphdr) + MAX_IPOPTLEN + \
120 sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE)
121
122 static u16 frag_get_pending_idx(skb_frag_t *frag)
123 {
124 return (u16)frag->page_offset;
125 }
126
127 static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
128 {
129 frag->page_offset = pending_idx;
130 }
131
132 static inline pending_ring_idx_t pending_index(unsigned i)
133 {
134 return i & (MAX_PENDING_REQS-1);
135 }
136
137 static inline pending_ring_idx_t nr_pending_reqs(struct xenvif *vif)
138 {
139 return MAX_PENDING_REQS -
140 vif->pending_prod + vif->pending_cons;
141 }
142
143 static int max_required_rx_slots(struct xenvif *vif)
144 {
145 int max = DIV_ROUND_UP(vif->dev->mtu, PAGE_SIZE);
146
147 /* XXX FIXME: RX path dependent on MAX_SKB_FRAGS */
148 if (vif->can_sg || vif->gso || vif->gso_prefix)
149 max += MAX_SKB_FRAGS + 1; /* extra_info + frags */
150
151 return max;
152 }
153
154 int xenvif_rx_ring_full(struct xenvif *vif)
155 {
156 RING_IDX peek = vif->rx_req_cons_peek;
157 RING_IDX needed = max_required_rx_slots(vif);
158
159 return ((vif->rx.sring->req_prod - peek) < needed) ||
160 ((vif->rx.rsp_prod_pvt + XEN_NETIF_RX_RING_SIZE - peek) < needed);
161 }
162
163 int xenvif_must_stop_queue(struct xenvif *vif)
164 {
165 if (!xenvif_rx_ring_full(vif))
166 return 0;
167
168 vif->rx.sring->req_event = vif->rx_req_cons_peek +
169 max_required_rx_slots(vif);
170 mb(); /* request notification /then/ check the queue */
171
172 return xenvif_rx_ring_full(vif);
173 }
174
175 /*
176 * Returns true if we should start a new receive buffer instead of
177 * adding 'size' bytes to a buffer which currently contains 'offset'
178 * bytes.
179 */
180 static bool start_new_rx_buffer(int offset, unsigned long size, int head)
181 {
182 /* simple case: we have completely filled the current buffer. */
183 if (offset == MAX_BUFFER_OFFSET)
184 return true;
185
186 /*
187 * complex case: start a fresh buffer if the current frag
188 * would overflow the current buffer but only if:
189 * (i) this frag would fit completely in the next buffer
190 * and (ii) there is already some data in the current buffer
191 * and (iii) this is not the head buffer.
192 *
193 * Where:
194 * - (i) stops us splitting a frag into two copies
195 * unless the frag is too large for a single buffer.
196 * - (ii) stops us from leaving a buffer pointlessly empty.
197 * - (iii) stops us leaving the first buffer
198 * empty. Strictly speaking this is already covered
199 * by (ii) but is explicitly checked because
200 * netfront relies on the first buffer being
201 * non-empty and can crash otherwise.
202 *
203 * This means we will effectively linearise small
204 * frags but do not needlessly split large buffers
205 * into multiple copies tend to give large frags their
206 * own buffers as before.
207 */
208 if ((offset + size > MAX_BUFFER_OFFSET) &&
209 (size <= MAX_BUFFER_OFFSET) && offset && !head)
210 return true;
211
212 return false;
213 }
214
215 struct xenvif_count_slot_state {
216 unsigned long copy_off;
217 bool head;
218 };
219
220 unsigned int xenvif_count_frag_slots(struct xenvif *vif,
221 unsigned long offset, unsigned long size,
222 struct xenvif_count_slot_state *state)
223 {
224 unsigned count = 0;
225
226 offset &= ~PAGE_MASK;
227
228 while (size > 0) {
229 unsigned long bytes;
230
231 bytes = PAGE_SIZE - offset;
232
233 if (bytes > size)
234 bytes = size;
235
236 if (start_new_rx_buffer(state->copy_off, bytes, state->head)) {
237 count++;
238 state->copy_off = 0;
239 }
240
241 if (state->copy_off + bytes > MAX_BUFFER_OFFSET)
242 bytes = MAX_BUFFER_OFFSET - state->copy_off;
243
244 state->copy_off += bytes;
245
246 offset += bytes;
247 size -= bytes;
248
249 if (offset == PAGE_SIZE)
250 offset = 0;
251
252 state->head = false;
253 }
254
255 return count;
256 }
257
258 /*
259 * Figure out how many ring slots we're going to need to send @skb to
260 * the guest. This function is essentially a dry run of
261 * xenvif_gop_frag_copy.
262 */
263 unsigned int xenvif_count_skb_slots(struct xenvif *vif, struct sk_buff *skb)
264 {
265 struct xenvif_count_slot_state state;
266 unsigned int count;
267 unsigned char *data;
268 unsigned i;
269
270 state.head = true;
271 state.copy_off = 0;
272
273 /* Slot for the first (partial) page of data. */
274 count = 1;
275
276 /* Need a slot for the GSO prefix for GSO extra data? */
277 if (skb_shinfo(skb)->gso_size)
278 count++;
279
280 data = skb->data;
281 while (data < skb_tail_pointer(skb)) {
282 unsigned long offset = offset_in_page(data);
283 unsigned long size = PAGE_SIZE - offset;
284
285 if (data + size > skb_tail_pointer(skb))
286 size = skb_tail_pointer(skb) - data;
287
288 count += xenvif_count_frag_slots(vif, offset, size, &state);
289
290 data += size;
291 }
292
293 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
294 unsigned long size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
295 unsigned long offset = skb_shinfo(skb)->frags[i].page_offset;
296
297 count += xenvif_count_frag_slots(vif, offset, size, &state);
298 }
299 return count;
300 }
301
302 struct netrx_pending_operations {
303 unsigned copy_prod, copy_cons;
304 unsigned meta_prod, meta_cons;
305 struct gnttab_copy *copy;
306 struct xenvif_rx_meta *meta;
307 int copy_off;
308 grant_ref_t copy_gref;
309 };
310
311 static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif *vif,
312 struct netrx_pending_operations *npo)
313 {
314 struct xenvif_rx_meta *meta;
315 struct xen_netif_rx_request *req;
316
317 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
318
319 meta = npo->meta + npo->meta_prod++;
320 meta->gso_size = 0;
321 meta->size = 0;
322 meta->id = req->id;
323
324 npo->copy_off = 0;
325 npo->copy_gref = req->gref;
326
327 return meta;
328 }
329
330 /*
331 * Set up the grant operations for this fragment. If it's a flipping
332 * interface, we also set up the unmap request from here.
333 */
334 static void xenvif_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb,
335 struct netrx_pending_operations *npo,
336 struct page *page, unsigned long size,
337 unsigned long offset, int *head)
338 {
339 struct gnttab_copy *copy_gop;
340 struct xenvif_rx_meta *meta;
341 unsigned long bytes;
342
343 /* Data must not cross a page boundary. */
344 BUG_ON(size + offset > PAGE_SIZE<<compound_order(page));
345
346 meta = npo->meta + npo->meta_prod - 1;
347
348 /* Skip unused frames from start of page */
349 page += offset >> PAGE_SHIFT;
350 offset &= ~PAGE_MASK;
351
352 while (size > 0) {
353 BUG_ON(offset >= PAGE_SIZE);
354 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
355
356 bytes = PAGE_SIZE - offset;
357
358 if (bytes > size)
359 bytes = size;
360
361 if (start_new_rx_buffer(npo->copy_off, bytes, *head)) {
362 /*
363 * Netfront requires there to be some data in the head
364 * buffer.
365 */
366 BUG_ON(*head);
367
368 meta = get_next_rx_buffer(vif, npo);
369 }
370
371 if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
372 bytes = MAX_BUFFER_OFFSET - npo->copy_off;
373
374 copy_gop = npo->copy + npo->copy_prod++;
375 copy_gop->flags = GNTCOPY_dest_gref;
376 copy_gop->len = bytes;
377
378 copy_gop->source.domid = DOMID_SELF;
379 copy_gop->source.u.gmfn = virt_to_mfn(page_address(page));
380 copy_gop->source.offset = offset;
381
382 copy_gop->dest.domid = vif->domid;
383 copy_gop->dest.offset = npo->copy_off;
384 copy_gop->dest.u.ref = npo->copy_gref;
385
386 npo->copy_off += bytes;
387 meta->size += bytes;
388
389 offset += bytes;
390 size -= bytes;
391
392 /* Next frame */
393 if (offset == PAGE_SIZE && size) {
394 BUG_ON(!PageCompound(page));
395 page++;
396 offset = 0;
397 }
398
399 /* Leave a gap for the GSO descriptor. */
400 if (*head && skb_shinfo(skb)->gso_size && !vif->gso_prefix)
401 vif->rx.req_cons++;
402
403 *head = 0; /* There must be something in this buffer now. */
404
405 }
406 }
407
408 /*
409 * Prepare an SKB to be transmitted to the frontend.
410 *
411 * This function is responsible for allocating grant operations, meta
412 * structures, etc.
413 *
414 * It returns the number of meta structures consumed. The number of
415 * ring slots used is always equal to the number of meta slots used
416 * plus the number of GSO descriptors used. Currently, we use either
417 * zero GSO descriptors (for non-GSO packets) or one descriptor (for
418 * frontend-side LRO).
419 */
420 static int xenvif_gop_skb(struct sk_buff *skb,
421 struct netrx_pending_operations *npo)
422 {
423 struct xenvif *vif = netdev_priv(skb->dev);
424 int nr_frags = skb_shinfo(skb)->nr_frags;
425 int i;
426 struct xen_netif_rx_request *req;
427 struct xenvif_rx_meta *meta;
428 unsigned char *data;
429 int head = 1;
430 int old_meta_prod;
431
432 old_meta_prod = npo->meta_prod;
433
434 /* Set up a GSO prefix descriptor, if necessary */
435 if (skb_shinfo(skb)->gso_size && vif->gso_prefix) {
436 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
437 meta = npo->meta + npo->meta_prod++;
438 meta->gso_size = skb_shinfo(skb)->gso_size;
439 meta->size = 0;
440 meta->id = req->id;
441 }
442
443 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
444 meta = npo->meta + npo->meta_prod++;
445
446 if (!vif->gso_prefix)
447 meta->gso_size = skb_shinfo(skb)->gso_size;
448 else
449 meta->gso_size = 0;
450
451 meta->size = 0;
452 meta->id = req->id;
453 npo->copy_off = 0;
454 npo->copy_gref = req->gref;
455
456 data = skb->data;
457 while (data < skb_tail_pointer(skb)) {
458 unsigned int offset = offset_in_page(data);
459 unsigned int len = PAGE_SIZE - offset;
460
461 if (data + len > skb_tail_pointer(skb))
462 len = skb_tail_pointer(skb) - data;
463
464 xenvif_gop_frag_copy(vif, skb, npo,
465 virt_to_page(data), len, offset, &head);
466 data += len;
467 }
468
469 for (i = 0; i < nr_frags; i++) {
470 xenvif_gop_frag_copy(vif, skb, npo,
471 skb_frag_page(&skb_shinfo(skb)->frags[i]),
472 skb_frag_size(&skb_shinfo(skb)->frags[i]),
473 skb_shinfo(skb)->frags[i].page_offset,
474 &head);
475 }
476
477 return npo->meta_prod - old_meta_prod;
478 }
479
480 /*
481 * This is a twin to xenvif_gop_skb. Assume that xenvif_gop_skb was
482 * used to set up the operations on the top of
483 * netrx_pending_operations, which have since been done. Check that
484 * they didn't give any errors and advance over them.
485 */
486 static int xenvif_check_gop(struct xenvif *vif, int nr_meta_slots,
487 struct netrx_pending_operations *npo)
488 {
489 struct gnttab_copy *copy_op;
490 int status = XEN_NETIF_RSP_OKAY;
491 int i;
492
493 for (i = 0; i < nr_meta_slots; i++) {
494 copy_op = npo->copy + npo->copy_cons++;
495 if (copy_op->status != GNTST_okay) {
496 netdev_dbg(vif->dev,
497 "Bad status %d from copy to DOM%d.\n",
498 copy_op->status, vif->domid);
499 status = XEN_NETIF_RSP_ERROR;
500 }
501 }
502
503 return status;
504 }
505
506 static void xenvif_add_frag_responses(struct xenvif *vif, int status,
507 struct xenvif_rx_meta *meta,
508 int nr_meta_slots)
509 {
510 int i;
511 unsigned long offset;
512
513 /* No fragments used */
514 if (nr_meta_slots <= 1)
515 return;
516
517 nr_meta_slots--;
518
519 for (i = 0; i < nr_meta_slots; i++) {
520 int flags;
521 if (i == nr_meta_slots - 1)
522 flags = 0;
523 else
524 flags = XEN_NETRXF_more_data;
525
526 offset = 0;
527 make_rx_response(vif, meta[i].id, status, offset,
528 meta[i].size, flags);
529 }
530 }
531
532 struct skb_cb_overlay {
533 int meta_slots_used;
534 };
535
536 static void xenvif_kick_thread(struct xenvif *vif)
537 {
538 wake_up(&vif->wq);
539 }
540
541 void xenvif_rx_action(struct xenvif *vif)
542 {
543 s8 status;
544 u16 flags;
545 struct xen_netif_rx_response *resp;
546 struct sk_buff_head rxq;
547 struct sk_buff *skb;
548 LIST_HEAD(notify);
549 int ret;
550 int nr_frags;
551 int count;
552 unsigned long offset;
553 struct skb_cb_overlay *sco;
554 int need_to_notify = 0;
555
556 struct netrx_pending_operations npo = {
557 .copy = vif->grant_copy_op,
558 .meta = vif->meta,
559 };
560
561 skb_queue_head_init(&rxq);
562
563 count = 0;
564
565 while ((skb = skb_dequeue(&vif->rx_queue)) != NULL) {
566 vif = netdev_priv(skb->dev);
567 nr_frags = skb_shinfo(skb)->nr_frags;
568
569 sco = (struct skb_cb_overlay *)skb->cb;
570 sco->meta_slots_used = xenvif_gop_skb(skb, &npo);
571
572 count += nr_frags + 1;
573
574 __skb_queue_tail(&rxq, skb);
575
576 /* Filled the batch queue? */
577 /* XXX FIXME: RX path dependent on MAX_SKB_FRAGS */
578 if (count + MAX_SKB_FRAGS >= XEN_NETIF_RX_RING_SIZE)
579 break;
580 }
581
582 BUG_ON(npo.meta_prod > ARRAY_SIZE(vif->meta));
583
584 if (!npo.copy_prod)
585 return;
586
587 BUG_ON(npo.copy_prod > ARRAY_SIZE(vif->grant_copy_op));
588 gnttab_batch_copy(vif->grant_copy_op, npo.copy_prod);
589
590 while ((skb = __skb_dequeue(&rxq)) != NULL) {
591 sco = (struct skb_cb_overlay *)skb->cb;
592
593 vif = netdev_priv(skb->dev);
594
595 if (vif->meta[npo.meta_cons].gso_size && vif->gso_prefix) {
596 resp = RING_GET_RESPONSE(&vif->rx,
597 vif->rx.rsp_prod_pvt++);
598
599 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
600
601 resp->offset = vif->meta[npo.meta_cons].gso_size;
602 resp->id = vif->meta[npo.meta_cons].id;
603 resp->status = sco->meta_slots_used;
604
605 npo.meta_cons++;
606 sco->meta_slots_used--;
607 }
608
609
610 vif->dev->stats.tx_bytes += skb->len;
611 vif->dev->stats.tx_packets++;
612
613 status = xenvif_check_gop(vif, sco->meta_slots_used, &npo);
614
615 if (sco->meta_slots_used == 1)
616 flags = 0;
617 else
618 flags = XEN_NETRXF_more_data;
619
620 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
621 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
622 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
623 /* remote but checksummed. */
624 flags |= XEN_NETRXF_data_validated;
625
626 offset = 0;
627 resp = make_rx_response(vif, vif->meta[npo.meta_cons].id,
628 status, offset,
629 vif->meta[npo.meta_cons].size,
630 flags);
631
632 if (vif->meta[npo.meta_cons].gso_size && !vif->gso_prefix) {
633 struct xen_netif_extra_info *gso =
634 (struct xen_netif_extra_info *)
635 RING_GET_RESPONSE(&vif->rx,
636 vif->rx.rsp_prod_pvt++);
637
638 resp->flags |= XEN_NETRXF_extra_info;
639
640 gso->u.gso.size = vif->meta[npo.meta_cons].gso_size;
641 gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
642 gso->u.gso.pad = 0;
643 gso->u.gso.features = 0;
644
645 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
646 gso->flags = 0;
647 }
648
649 xenvif_add_frag_responses(vif, status,
650 vif->meta + npo.meta_cons + 1,
651 sco->meta_slots_used);
652
653 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret);
654
655 if (ret)
656 need_to_notify = 1;
657
658 xenvif_notify_tx_completion(vif);
659
660 npo.meta_cons += sco->meta_slots_used;
661 dev_kfree_skb(skb);
662 }
663
664 if (need_to_notify)
665 notify_remote_via_irq(vif->rx_irq);
666
667 /* More work to do? */
668 if (!skb_queue_empty(&vif->rx_queue))
669 xenvif_kick_thread(vif);
670 }
671
672 void xenvif_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb)
673 {
674 skb_queue_tail(&vif->rx_queue, skb);
675
676 xenvif_kick_thread(vif);
677 }
678
679 void xenvif_check_rx_xenvif(struct xenvif *vif)
680 {
681 int more_to_do;
682
683 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
684
685 if (more_to_do)
686 napi_schedule(&vif->napi);
687 }
688
689 static void tx_add_credit(struct xenvif *vif)
690 {
691 unsigned long max_burst, max_credit;
692
693 /*
694 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
695 * Otherwise the interface can seize up due to insufficient credit.
696 */
697 max_burst = RING_GET_REQUEST(&vif->tx, vif->tx.req_cons)->size;
698 max_burst = min(max_burst, 131072UL);
699 max_burst = max(max_burst, vif->credit_bytes);
700
701 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
702 max_credit = vif->remaining_credit + vif->credit_bytes;
703 if (max_credit < vif->remaining_credit)
704 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
705
706 vif->remaining_credit = min(max_credit, max_burst);
707 }
708
709 static void tx_credit_callback(unsigned long data)
710 {
711 struct xenvif *vif = (struct xenvif *)data;
712 tx_add_credit(vif);
713 xenvif_check_rx_xenvif(vif);
714 }
715
716 static void xenvif_tx_err(struct xenvif *vif,
717 struct xen_netif_tx_request *txp, RING_IDX end)
718 {
719 RING_IDX cons = vif->tx.req_cons;
720
721 do {
722 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
723 if (cons == end)
724 break;
725 txp = RING_GET_REQUEST(&vif->tx, cons++);
726 } while (1);
727 vif->tx.req_cons = cons;
728 }
729
730 static void xenvif_fatal_tx_err(struct xenvif *vif)
731 {
732 netdev_err(vif->dev, "fatal error; disabling device\n");
733 xenvif_carrier_off(vif);
734 }
735
736 static int xenvif_count_requests(struct xenvif *vif,
737 struct xen_netif_tx_request *first,
738 struct xen_netif_tx_request *txp,
739 int work_to_do)
740 {
741 RING_IDX cons = vif->tx.req_cons;
742 int slots = 0;
743 int drop_err = 0;
744 int more_data;
745
746 if (!(first->flags & XEN_NETTXF_more_data))
747 return 0;
748
749 do {
750 struct xen_netif_tx_request dropped_tx = { 0 };
751
752 if (slots >= work_to_do) {
753 netdev_err(vif->dev,
754 "Asked for %d slots but exceeds this limit\n",
755 work_to_do);
756 xenvif_fatal_tx_err(vif);
757 return -ENODATA;
758 }
759
760 /* This guest is really using too many slots and
761 * considered malicious.
762 */
763 if (unlikely(slots >= fatal_skb_slots)) {
764 netdev_err(vif->dev,
765 "Malicious frontend using %d slots, threshold %u\n",
766 slots, fatal_skb_slots);
767 xenvif_fatal_tx_err(vif);
768 return -E2BIG;
769 }
770
771 /* Xen network protocol had implicit dependency on
772 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
773 * the historical MAX_SKB_FRAGS value 18 to honor the
774 * same behavior as before. Any packet using more than
775 * 18 slots but less than fatal_skb_slots slots is
776 * dropped
777 */
778 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
779 if (net_ratelimit())
780 netdev_dbg(vif->dev,
781 "Too many slots (%d) exceeding limit (%d), dropping packet\n",
782 slots, XEN_NETBK_LEGACY_SLOTS_MAX);
783 drop_err = -E2BIG;
784 }
785
786 if (drop_err)
787 txp = &dropped_tx;
788
789 memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + slots),
790 sizeof(*txp));
791
792 /* If the guest submitted a frame >= 64 KiB then
793 * first->size overflowed and following slots will
794 * appear to be larger than the frame.
795 *
796 * This cannot be fatal error as there are buggy
797 * frontends that do this.
798 *
799 * Consume all slots and drop the packet.
800 */
801 if (!drop_err && txp->size > first->size) {
802 if (net_ratelimit())
803 netdev_dbg(vif->dev,
804 "Invalid tx request, slot size %u > remaining size %u\n",
805 txp->size, first->size);
806 drop_err = -EIO;
807 }
808
809 first->size -= txp->size;
810 slots++;
811
812 if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
813 netdev_err(vif->dev, "Cross page boundary, txp->offset: %x, size: %u\n",
814 txp->offset, txp->size);
815 xenvif_fatal_tx_err(vif);
816 return -EINVAL;
817 }
818
819 more_data = txp->flags & XEN_NETTXF_more_data;
820
821 if (!drop_err)
822 txp++;
823
824 } while (more_data);
825
826 if (drop_err) {
827 xenvif_tx_err(vif, first, cons + slots);
828 return drop_err;
829 }
830
831 return slots;
832 }
833
834 static struct page *xenvif_alloc_page(struct xenvif *vif,
835 u16 pending_idx)
836 {
837 struct page *page;
838
839 page = alloc_page(GFP_ATOMIC|__GFP_COLD);
840 if (!page)
841 return NULL;
842 vif->mmap_pages[pending_idx] = page;
843
844 return page;
845 }
846
847 static struct gnttab_copy *xenvif_get_requests(struct xenvif *vif,
848 struct sk_buff *skb,
849 struct xen_netif_tx_request *txp,
850 struct gnttab_copy *gop)
851 {
852 struct skb_shared_info *shinfo = skb_shinfo(skb);
853 skb_frag_t *frags = shinfo->frags;
854 u16 pending_idx = *((u16 *)skb->data);
855 u16 head_idx = 0;
856 int slot, start;
857 struct page *page;
858 pending_ring_idx_t index, start_idx = 0;
859 uint16_t dst_offset;
860 unsigned int nr_slots;
861 struct pending_tx_info *first = NULL;
862
863 /* At this point shinfo->nr_frags is in fact the number of
864 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
865 */
866 nr_slots = shinfo->nr_frags;
867
868 /* Skip first skb fragment if it is on same page as header fragment. */
869 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
870
871 /* Coalesce tx requests, at this point the packet passed in
872 * should be <= 64K. Any packets larger than 64K have been
873 * handled in xenvif_count_requests().
874 */
875 for (shinfo->nr_frags = slot = start; slot < nr_slots;
876 shinfo->nr_frags++) {
877 struct pending_tx_info *pending_tx_info =
878 vif->pending_tx_info;
879
880 page = alloc_page(GFP_ATOMIC|__GFP_COLD);
881 if (!page)
882 goto err;
883
884 dst_offset = 0;
885 first = NULL;
886 while (dst_offset < PAGE_SIZE && slot < nr_slots) {
887 gop->flags = GNTCOPY_source_gref;
888
889 gop->source.u.ref = txp->gref;
890 gop->source.domid = vif->domid;
891 gop->source.offset = txp->offset;
892
893 gop->dest.domid = DOMID_SELF;
894
895 gop->dest.offset = dst_offset;
896 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
897
898 if (dst_offset + txp->size > PAGE_SIZE) {
899 /* This page can only merge a portion
900 * of tx request. Do not increment any
901 * pointer / counter here. The txp
902 * will be dealt with in future
903 * rounds, eventually hitting the
904 * `else` branch.
905 */
906 gop->len = PAGE_SIZE - dst_offset;
907 txp->offset += gop->len;
908 txp->size -= gop->len;
909 dst_offset += gop->len; /* quit loop */
910 } else {
911 /* This tx request can be merged in the page */
912 gop->len = txp->size;
913 dst_offset += gop->len;
914
915 index = pending_index(vif->pending_cons++);
916
917 pending_idx = vif->pending_ring[index];
918
919 memcpy(&pending_tx_info[pending_idx].req, txp,
920 sizeof(*txp));
921
922 /* Poison these fields, corresponding
923 * fields for head tx req will be set
924 * to correct values after the loop.
925 */
926 vif->mmap_pages[pending_idx] = (void *)(~0UL);
927 pending_tx_info[pending_idx].head =
928 INVALID_PENDING_RING_IDX;
929
930 if (!first) {
931 first = &pending_tx_info[pending_idx];
932 start_idx = index;
933 head_idx = pending_idx;
934 }
935
936 txp++;
937 slot++;
938 }
939
940 gop++;
941 }
942
943 first->req.offset = 0;
944 first->req.size = dst_offset;
945 first->head = start_idx;
946 vif->mmap_pages[head_idx] = page;
947 frag_set_pending_idx(&frags[shinfo->nr_frags], head_idx);
948 }
949
950 BUG_ON(shinfo->nr_frags > MAX_SKB_FRAGS);
951
952 return gop;
953 err:
954 /* Unwind, freeing all pages and sending error responses. */
955 while (shinfo->nr_frags-- > start) {
956 xenvif_idx_release(vif,
957 frag_get_pending_idx(&frags[shinfo->nr_frags]),
958 XEN_NETIF_RSP_ERROR);
959 }
960 /* The head too, if necessary. */
961 if (start)
962 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
963
964 return NULL;
965 }
966
967 static int xenvif_tx_check_gop(struct xenvif *vif,
968 struct sk_buff *skb,
969 struct gnttab_copy **gopp)
970 {
971 struct gnttab_copy *gop = *gopp;
972 u16 pending_idx = *((u16 *)skb->data);
973 struct skb_shared_info *shinfo = skb_shinfo(skb);
974 struct pending_tx_info *tx_info;
975 int nr_frags = shinfo->nr_frags;
976 int i, err, start;
977 u16 peek; /* peek into next tx request */
978
979 /* Check status of header. */
980 err = gop->status;
981 if (unlikely(err))
982 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
983
984 /* Skip first skb fragment if it is on same page as header fragment. */
985 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
986
987 for (i = start; i < nr_frags; i++) {
988 int j, newerr;
989 pending_ring_idx_t head;
990
991 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
992 tx_info = &vif->pending_tx_info[pending_idx];
993 head = tx_info->head;
994
995 /* Check error status: if okay then remember grant handle. */
996 do {
997 newerr = (++gop)->status;
998 if (newerr)
999 break;
1000 peek = vif->pending_ring[pending_index(++head)];
1001 } while (!pending_tx_is_head(vif, peek));
1002
1003 if (likely(!newerr)) {
1004 /* Had a previous error? Invalidate this fragment. */
1005 if (unlikely(err))
1006 xenvif_idx_release(vif, pending_idx,
1007 XEN_NETIF_RSP_OKAY);
1008 continue;
1009 }
1010
1011 /* Error on this fragment: respond to client with an error. */
1012 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
1013
1014 /* Not the first error? Preceding frags already invalidated. */
1015 if (err)
1016 continue;
1017
1018 /* First error: invalidate header and preceding fragments. */
1019 pending_idx = *((u16 *)skb->data);
1020 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY);
1021 for (j = start; j < i; j++) {
1022 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
1023 xenvif_idx_release(vif, pending_idx,
1024 XEN_NETIF_RSP_OKAY);
1025 }
1026
1027 /* Remember the error: invalidate all subsequent fragments. */
1028 err = newerr;
1029 }
1030
1031 *gopp = gop + 1;
1032 return err;
1033 }
1034
1035 static void xenvif_fill_frags(struct xenvif *vif, struct sk_buff *skb)
1036 {
1037 struct skb_shared_info *shinfo = skb_shinfo(skb);
1038 int nr_frags = shinfo->nr_frags;
1039 int i;
1040
1041 for (i = 0; i < nr_frags; i++) {
1042 skb_frag_t *frag = shinfo->frags + i;
1043 struct xen_netif_tx_request *txp;
1044 struct page *page;
1045 u16 pending_idx;
1046
1047 pending_idx = frag_get_pending_idx(frag);
1048
1049 txp = &vif->pending_tx_info[pending_idx].req;
1050 page = virt_to_page(idx_to_kaddr(vif, pending_idx));
1051 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
1052 skb->len += txp->size;
1053 skb->data_len += txp->size;
1054 skb->truesize += txp->size;
1055
1056 /* Take an extra reference to offset xenvif_idx_release */
1057 get_page(vif->mmap_pages[pending_idx]);
1058 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY);
1059 }
1060 }
1061
1062 static int xenvif_get_extras(struct xenvif *vif,
1063 struct xen_netif_extra_info *extras,
1064 int work_to_do)
1065 {
1066 struct xen_netif_extra_info extra;
1067 RING_IDX cons = vif->tx.req_cons;
1068
1069 do {
1070 if (unlikely(work_to_do-- <= 0)) {
1071 netdev_err(vif->dev, "Missing extra info\n");
1072 xenvif_fatal_tx_err(vif);
1073 return -EBADR;
1074 }
1075
1076 memcpy(&extra, RING_GET_REQUEST(&vif->tx, cons),
1077 sizeof(extra));
1078 if (unlikely(!extra.type ||
1079 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1080 vif->tx.req_cons = ++cons;
1081 netdev_err(vif->dev,
1082 "Invalid extra type: %d\n", extra.type);
1083 xenvif_fatal_tx_err(vif);
1084 return -EINVAL;
1085 }
1086
1087 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1088 vif->tx.req_cons = ++cons;
1089 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1090
1091 return work_to_do;
1092 }
1093
1094 static int xenvif_set_skb_gso(struct xenvif *vif,
1095 struct sk_buff *skb,
1096 struct xen_netif_extra_info *gso)
1097 {
1098 if (!gso->u.gso.size) {
1099 netdev_err(vif->dev, "GSO size must not be zero.\n");
1100 xenvif_fatal_tx_err(vif);
1101 return -EINVAL;
1102 }
1103
1104 /* Currently only TCPv4 S.O. is supported. */
1105 if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
1106 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1107 xenvif_fatal_tx_err(vif);
1108 return -EINVAL;
1109 }
1110
1111 skb_shinfo(skb)->gso_size = gso->u.gso.size;
1112 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1113
1114 /* Header must be checked, and gso_segs computed. */
1115 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1116 skb_shinfo(skb)->gso_segs = 0;
1117
1118 return 0;
1119 }
1120
1121 static int checksum_setup(struct xenvif *vif, struct sk_buff *skb)
1122 {
1123 struct iphdr *iph;
1124 int err = -EPROTO;
1125 int recalculate_partial_csum = 0;
1126
1127 /*
1128 * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1129 * peers can fail to set NETRXF_csum_blank when sending a GSO
1130 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1131 * recalculate the partial checksum.
1132 */
1133 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1134 vif->rx_gso_checksum_fixup++;
1135 skb->ip_summed = CHECKSUM_PARTIAL;
1136 recalculate_partial_csum = 1;
1137 }
1138
1139 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1140 if (skb->ip_summed != CHECKSUM_PARTIAL)
1141 return 0;
1142
1143 if (skb->protocol != htons(ETH_P_IP))
1144 goto out;
1145
1146 iph = (void *)skb->data;
1147 switch (iph->protocol) {
1148 case IPPROTO_TCP:
1149 if (!skb_partial_csum_set(skb, 4 * iph->ihl,
1150 offsetof(struct tcphdr, check)))
1151 goto out;
1152
1153 if (recalculate_partial_csum) {
1154 struct tcphdr *tcph = tcp_hdr(skb);
1155 tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1156 skb->len - iph->ihl*4,
1157 IPPROTO_TCP, 0);
1158 }
1159 break;
1160 case IPPROTO_UDP:
1161 if (!skb_partial_csum_set(skb, 4 * iph->ihl,
1162 offsetof(struct udphdr, check)))
1163 goto out;
1164
1165 if (recalculate_partial_csum) {
1166 struct udphdr *udph = udp_hdr(skb);
1167 udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1168 skb->len - iph->ihl*4,
1169 IPPROTO_UDP, 0);
1170 }
1171 break;
1172 default:
1173 if (net_ratelimit())
1174 netdev_err(vif->dev,
1175 "Attempting to checksum a non-TCP/UDP packet, dropping a protocol %d packet\n",
1176 iph->protocol);
1177 goto out;
1178 }
1179
1180 err = 0;
1181
1182 out:
1183 return err;
1184 }
1185
1186 static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
1187 {
1188 unsigned long now = jiffies;
1189 unsigned long next_credit =
1190 vif->credit_timeout.expires +
1191 msecs_to_jiffies(vif->credit_usec / 1000);
1192
1193 /* Timer could already be pending in rare cases. */
1194 if (timer_pending(&vif->credit_timeout))
1195 return true;
1196
1197 /* Passed the point where we can replenish credit? */
1198 if (time_after_eq(now, next_credit)) {
1199 vif->credit_timeout.expires = now;
1200 tx_add_credit(vif);
1201 }
1202
1203 /* Still too big to send right now? Set a callback. */
1204 if (size > vif->remaining_credit) {
1205 vif->credit_timeout.data =
1206 (unsigned long)vif;
1207 vif->credit_timeout.function =
1208 tx_credit_callback;
1209 mod_timer(&vif->credit_timeout,
1210 next_credit);
1211
1212 return true;
1213 }
1214
1215 return false;
1216 }
1217
1218 static unsigned xenvif_tx_build_gops(struct xenvif *vif)
1219 {
1220 struct gnttab_copy *gop = vif->tx_copy_ops, *request_gop;
1221 struct sk_buff *skb;
1222 int ret;
1223
1224 while ((nr_pending_reqs(vif) + XEN_NETBK_LEGACY_SLOTS_MAX
1225 < MAX_PENDING_REQS)) {
1226 struct xen_netif_tx_request txreq;
1227 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
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 if (vif->tx.sring->req_prod - vif->tx.req_cons >
1237 XEN_NETIF_TX_RING_SIZE) {
1238 netdev_err(vif->dev,
1239 "Impossible number of requests. "
1240 "req_prod %d, req_cons %d, size %ld\n",
1241 vif->tx.sring->req_prod, vif->tx.req_cons,
1242 XEN_NETIF_TX_RING_SIZE);
1243 xenvif_fatal_tx_err(vif);
1244 continue;
1245 }
1246
1247 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, work_to_do);
1248 if (!work_to_do)
1249 break;
1250
1251 idx = vif->tx.req_cons;
1252 rmb(); /* Ensure that we see the request before we copy it. */
1253 memcpy(&txreq, RING_GET_REQUEST(&vif->tx, idx), sizeof(txreq));
1254
1255 /* Credit-based scheduling. */
1256 if (txreq.size > vif->remaining_credit &&
1257 tx_credit_exceeded(vif, txreq.size))
1258 break;
1259
1260 vif->remaining_credit -= txreq.size;
1261
1262 work_to_do--;
1263 vif->tx.req_cons = ++idx;
1264
1265 memset(extras, 0, sizeof(extras));
1266 if (txreq.flags & XEN_NETTXF_extra_info) {
1267 work_to_do = xenvif_get_extras(vif, extras,
1268 work_to_do);
1269 idx = vif->tx.req_cons;
1270 if (unlikely(work_to_do < 0))
1271 break;
1272 }
1273
1274 ret = xenvif_count_requests(vif, &txreq, txfrags, work_to_do);
1275 if (unlikely(ret < 0))
1276 break;
1277
1278 idx += ret;
1279
1280 if (unlikely(txreq.size < ETH_HLEN)) {
1281 netdev_dbg(vif->dev,
1282 "Bad packet size: %d\n", txreq.size);
1283 xenvif_tx_err(vif, &txreq, idx);
1284 break;
1285 }
1286
1287 /* No crossing a page as the payload mustn't fragment. */
1288 if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
1289 netdev_err(vif->dev,
1290 "txreq.offset: %x, size: %u, end: %lu\n",
1291 txreq.offset, txreq.size,
1292 (txreq.offset&~PAGE_MASK) + txreq.size);
1293 xenvif_fatal_tx_err(vif);
1294 break;
1295 }
1296
1297 index = pending_index(vif->pending_cons);
1298 pending_idx = vif->pending_ring[index];
1299
1300 data_len = (txreq.size > PKT_PROT_LEN &&
1301 ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
1302 PKT_PROT_LEN : txreq.size;
1303
1304 skb = alloc_skb(data_len + NET_SKB_PAD + NET_IP_ALIGN,
1305 GFP_ATOMIC | __GFP_NOWARN);
1306 if (unlikely(skb == NULL)) {
1307 netdev_dbg(vif->dev,
1308 "Can't allocate a skb in start_xmit.\n");
1309 xenvif_tx_err(vif, &txreq, idx);
1310 break;
1311 }
1312
1313 /* Packets passed to netif_rx() must have some headroom. */
1314 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
1315
1316 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1317 struct xen_netif_extra_info *gso;
1318 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1319
1320 if (xenvif_set_skb_gso(vif, skb, gso)) {
1321 /* Failure in xenvif_set_skb_gso is fatal. */
1322 kfree_skb(skb);
1323 break;
1324 }
1325 }
1326
1327 /* XXX could copy straight to head */
1328 page = xenvif_alloc_page(vif, pending_idx);
1329 if (!page) {
1330 kfree_skb(skb);
1331 xenvif_tx_err(vif, &txreq, idx);
1332 break;
1333 }
1334
1335 gop->source.u.ref = txreq.gref;
1336 gop->source.domid = vif->domid;
1337 gop->source.offset = txreq.offset;
1338
1339 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
1340 gop->dest.domid = DOMID_SELF;
1341 gop->dest.offset = txreq.offset;
1342
1343 gop->len = txreq.size;
1344 gop->flags = GNTCOPY_source_gref;
1345
1346 gop++;
1347
1348 memcpy(&vif->pending_tx_info[pending_idx].req,
1349 &txreq, sizeof(txreq));
1350 vif->pending_tx_info[pending_idx].head = index;
1351 *((u16 *)skb->data) = pending_idx;
1352
1353 __skb_put(skb, data_len);
1354
1355 skb_shinfo(skb)->nr_frags = ret;
1356 if (data_len < txreq.size) {
1357 skb_shinfo(skb)->nr_frags++;
1358 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1359 pending_idx);
1360 } else {
1361 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1362 INVALID_PENDING_IDX);
1363 }
1364
1365 vif->pending_cons++;
1366
1367 request_gop = xenvif_get_requests(vif, skb, txfrags, gop);
1368 if (request_gop == NULL) {
1369 kfree_skb(skb);
1370 xenvif_tx_err(vif, &txreq, idx);
1371 break;
1372 }
1373 gop = request_gop;
1374
1375 __skb_queue_tail(&vif->tx_queue, skb);
1376
1377 vif->tx.req_cons = idx;
1378
1379 if ((gop-vif->tx_copy_ops) >= ARRAY_SIZE(vif->tx_copy_ops))
1380 break;
1381 }
1382
1383 return gop - vif->tx_copy_ops;
1384 }
1385
1386
1387 static int xenvif_tx_submit(struct xenvif *vif, int budget)
1388 {
1389 struct gnttab_copy *gop = vif->tx_copy_ops;
1390 struct sk_buff *skb;
1391 int work_done = 0;
1392
1393 while (work_done < budget &&
1394 (skb = __skb_dequeue(&vif->tx_queue)) != NULL) {
1395 struct xen_netif_tx_request *txp;
1396 u16 pending_idx;
1397 unsigned data_len;
1398
1399 pending_idx = *((u16 *)skb->data);
1400 txp = &vif->pending_tx_info[pending_idx].req;
1401
1402 /* Check the remap error code. */
1403 if (unlikely(xenvif_tx_check_gop(vif, skb, &gop))) {
1404 netdev_dbg(vif->dev, "netback grant failed.\n");
1405 skb_shinfo(skb)->nr_frags = 0;
1406 kfree_skb(skb);
1407 continue;
1408 }
1409
1410 data_len = skb->len;
1411 memcpy(skb->data,
1412 (void *)(idx_to_kaddr(vif, pending_idx)|txp->offset),
1413 data_len);
1414 if (data_len < txp->size) {
1415 /* Append the packet payload as a fragment. */
1416 txp->offset += data_len;
1417 txp->size -= data_len;
1418 } else {
1419 /* Schedule a response immediately. */
1420 xenvif_idx_release(vif, pending_idx,
1421 XEN_NETIF_RSP_OKAY);
1422 }
1423
1424 if (txp->flags & XEN_NETTXF_csum_blank)
1425 skb->ip_summed = CHECKSUM_PARTIAL;
1426 else if (txp->flags & XEN_NETTXF_data_validated)
1427 skb->ip_summed = CHECKSUM_UNNECESSARY;
1428
1429 xenvif_fill_frags(vif, skb);
1430
1431 /*
1432 * If the initial fragment was < PKT_PROT_LEN then
1433 * pull through some bytes from the other fragments to
1434 * increase the linear region to PKT_PROT_LEN bytes.
1435 */
1436 if (skb_headlen(skb) < PKT_PROT_LEN && skb_is_nonlinear(skb)) {
1437 int target = min_t(int, skb->len, PKT_PROT_LEN);
1438 __pskb_pull_tail(skb, target - skb_headlen(skb));
1439 }
1440
1441 skb->dev = vif->dev;
1442 skb->protocol = eth_type_trans(skb, skb->dev);
1443 skb_reset_network_header(skb);
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 skb_probe_transport_header(skb, 0);
1453
1454 vif->dev->stats.rx_bytes += skb->len;
1455 vif->dev->stats.rx_packets++;
1456
1457 work_done++;
1458
1459 netif_receive_skb(skb);
1460 }
1461
1462 return work_done;
1463 }
1464
1465 /* Called after netfront has transmitted */
1466 int xenvif_tx_action(struct xenvif *vif, int budget)
1467 {
1468 unsigned nr_gops;
1469 int work_done;
1470
1471 if (unlikely(!tx_work_todo(vif)))
1472 return 0;
1473
1474 nr_gops = xenvif_tx_build_gops(vif);
1475
1476 if (nr_gops == 0)
1477 return 0;
1478
1479 gnttab_batch_copy(vif->tx_copy_ops, nr_gops);
1480
1481 work_done = xenvif_tx_submit(vif, nr_gops);
1482
1483 return work_done;
1484 }
1485
1486 static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx,
1487 u8 status)
1488 {
1489 struct pending_tx_info *pending_tx_info;
1490 pending_ring_idx_t head;
1491 u16 peek; /* peek into next tx request */
1492
1493 BUG_ON(vif->mmap_pages[pending_idx] == (void *)(~0UL));
1494
1495 /* Already complete? */
1496 if (vif->mmap_pages[pending_idx] == NULL)
1497 return;
1498
1499 pending_tx_info = &vif->pending_tx_info[pending_idx];
1500
1501 head = pending_tx_info->head;
1502
1503 BUG_ON(!pending_tx_is_head(vif, head));
1504 BUG_ON(vif->pending_ring[pending_index(head)] != pending_idx);
1505
1506 do {
1507 pending_ring_idx_t index;
1508 pending_ring_idx_t idx = pending_index(head);
1509 u16 info_idx = vif->pending_ring[idx];
1510
1511 pending_tx_info = &vif->pending_tx_info[info_idx];
1512 make_tx_response(vif, &pending_tx_info->req, status);
1513
1514 /* Setting any number other than
1515 * INVALID_PENDING_RING_IDX indicates this slot is
1516 * starting a new packet / ending a previous packet.
1517 */
1518 pending_tx_info->head = 0;
1519
1520 index = pending_index(vif->pending_prod++);
1521 vif->pending_ring[index] = vif->pending_ring[info_idx];
1522
1523 peek = vif->pending_ring[pending_index(++head)];
1524
1525 } while (!pending_tx_is_head(vif, peek));
1526
1527 put_page(vif->mmap_pages[pending_idx]);
1528 vif->mmap_pages[pending_idx] = NULL;
1529 }
1530
1531
1532 static void make_tx_response(struct xenvif *vif,
1533 struct xen_netif_tx_request *txp,
1534 s8 st)
1535 {
1536 RING_IDX i = vif->tx.rsp_prod_pvt;
1537 struct xen_netif_tx_response *resp;
1538 int notify;
1539
1540 resp = RING_GET_RESPONSE(&vif->tx, i);
1541 resp->id = txp->id;
1542 resp->status = st;
1543
1544 if (txp->flags & XEN_NETTXF_extra_info)
1545 RING_GET_RESPONSE(&vif->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1546
1547 vif->tx.rsp_prod_pvt = ++i;
1548 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->tx, notify);
1549 if (notify)
1550 notify_remote_via_irq(vif->tx_irq);
1551 }
1552
1553 static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
1554 u16 id,
1555 s8 st,
1556 u16 offset,
1557 u16 size,
1558 u16 flags)
1559 {
1560 RING_IDX i = vif->rx.rsp_prod_pvt;
1561 struct xen_netif_rx_response *resp;
1562
1563 resp = RING_GET_RESPONSE(&vif->rx, i);
1564 resp->offset = offset;
1565 resp->flags = flags;
1566 resp->id = id;
1567 resp->status = (s16)size;
1568 if (st < 0)
1569 resp->status = (s16)st;
1570
1571 vif->rx.rsp_prod_pvt = ++i;
1572
1573 return resp;
1574 }
1575
1576 static inline int rx_work_todo(struct xenvif *vif)
1577 {
1578 return !skb_queue_empty(&vif->rx_queue);
1579 }
1580
1581 static inline int tx_work_todo(struct xenvif *vif)
1582 {
1583
1584 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->tx)) &&
1585 (nr_pending_reqs(vif) + XEN_NETBK_LEGACY_SLOTS_MAX
1586 < MAX_PENDING_REQS))
1587 return 1;
1588
1589 return 0;
1590 }
1591
1592 void xenvif_unmap_frontend_rings(struct xenvif *vif)
1593 {
1594 if (vif->tx.sring)
1595 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1596 vif->tx.sring);
1597 if (vif->rx.sring)
1598 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1599 vif->rx.sring);
1600 }
1601
1602 int xenvif_map_frontend_rings(struct xenvif *vif,
1603 grant_ref_t tx_ring_ref,
1604 grant_ref_t rx_ring_ref)
1605 {
1606 void *addr;
1607 struct xen_netif_tx_sring *txs;
1608 struct xen_netif_rx_sring *rxs;
1609
1610 int err = -ENOMEM;
1611
1612 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1613 tx_ring_ref, &addr);
1614 if (err)
1615 goto err;
1616
1617 txs = (struct xen_netif_tx_sring *)addr;
1618 BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
1619
1620 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1621 rx_ring_ref, &addr);
1622 if (err)
1623 goto err;
1624
1625 rxs = (struct xen_netif_rx_sring *)addr;
1626 BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
1627
1628 vif->rx_req_cons_peek = 0;
1629
1630 return 0;
1631
1632 err:
1633 xenvif_unmap_frontend_rings(vif);
1634 return err;
1635 }
1636
1637 int xenvif_kthread(void *data)
1638 {
1639 struct xenvif *vif = data;
1640
1641 while (!kthread_should_stop()) {
1642 wait_event_interruptible(vif->wq,
1643 rx_work_todo(vif) ||
1644 kthread_should_stop());
1645 if (kthread_should_stop())
1646 break;
1647
1648 if (rx_work_todo(vif))
1649 xenvif_rx_action(vif);
1650
1651 cond_resched();
1652 }
1653
1654 return 0;
1655 }
1656
1657 static int __init netback_init(void)
1658 {
1659 int rc = 0;
1660
1661 if (!xen_domain())
1662 return -ENODEV;
1663
1664 if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
1665 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
1666 fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
1667 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
1668 }
1669
1670 rc = xenvif_xenbus_init();
1671 if (rc)
1672 goto failed_init;
1673
1674 return 0;
1675
1676 failed_init:
1677 return rc;
1678 }
1679
1680 module_init(netback_init);
1681
1682 static void __exit netback_fini(void)
1683 {
1684 xenvif_xenbus_fini();
1685 }
1686 module_exit(netback_fini);
1687
1688 MODULE_LICENSE("Dual BSD/GPL");
1689 MODULE_ALIAS("xen-backend:vif");
Linux kernel - Deliverables
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