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drm/i915: export error state ref handling
[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 /*
51 * This is the maximum slots a skb can have. If a guest sends a skb
52 * which exceeds this limit it is considered malicious.
53 */
54 #define FATAL_SKB_SLOTS_DEFAULT 20
55 static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
56 module_param(fatal_skb_slots, uint, 0444);
57
58 /*
59 * To avoid confusion, we define XEN_NETBK_LEGACY_SLOTS_MAX indicating
60 * the maximum slots a valid packet can use. Now this value is defined
61 * to be XEN_NETIF_NR_SLOTS_MIN, which is supposed to be supported by
62 * all backend.
63 */
64 #define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN
65
66 typedef unsigned int pending_ring_idx_t;
67 #define INVALID_PENDING_RING_IDX (~0U)
68
69 struct pending_tx_info {
70 struct xen_netif_tx_request req; /* coalesced tx request */
71 struct xenvif *vif;
72 pending_ring_idx_t head; /* head != INVALID_PENDING_RING_IDX
73 * if it is head of one or more tx
74 * reqs
75 */
76 };
77
78 struct netbk_rx_meta {
79 int id;
80 int size;
81 int gso_size;
82 };
83
84 #define MAX_PENDING_REQS 256
85
86 /* Discriminate from any valid pending_idx value. */
87 #define INVALID_PENDING_IDX 0xFFFF
88
89 #define MAX_BUFFER_OFFSET PAGE_SIZE
90
91 /* extra field used in struct page */
92 union page_ext {
93 struct {
94 #if BITS_PER_LONG < 64
95 #define IDX_WIDTH 8
96 #define GROUP_WIDTH (BITS_PER_LONG - IDX_WIDTH)
97 unsigned int group:GROUP_WIDTH;
98 unsigned int idx:IDX_WIDTH;
99 #else
100 unsigned int group, idx;
101 #endif
102 } e;
103 void *mapping;
104 };
105
106 struct xen_netbk {
107 wait_queue_head_t wq;
108 struct task_struct *task;
109
110 struct sk_buff_head rx_queue;
111 struct sk_buff_head tx_queue;
112
113 struct timer_list net_timer;
114
115 struct page *mmap_pages[MAX_PENDING_REQS];
116
117 pending_ring_idx_t pending_prod;
118 pending_ring_idx_t pending_cons;
119 struct list_head net_schedule_list;
120
121 /* Protect the net_schedule_list in netif. */
122 spinlock_t net_schedule_list_lock;
123
124 atomic_t netfront_count;
125
126 struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
127 /* Coalescing tx requests before copying makes number of grant
128 * copy ops greater or equal to number of slots required. In
129 * worst case a tx request consumes 2 gnttab_copy.
130 */
131 struct gnttab_copy tx_copy_ops[2*MAX_PENDING_REQS];
132
133 u16 pending_ring[MAX_PENDING_REQS];
134
135 /*
136 * Given MAX_BUFFER_OFFSET of 4096 the worst case is that each
137 * head/fragment page uses 2 copy operations because it
138 * straddles two buffers in the frontend.
139 */
140 struct gnttab_copy grant_copy_op[2*XEN_NETIF_RX_RING_SIZE];
141 struct netbk_rx_meta meta[2*XEN_NETIF_RX_RING_SIZE];
142 };
143
144 static struct xen_netbk *xen_netbk;
145 static int xen_netbk_group_nr;
146
147 /*
148 * If head != INVALID_PENDING_RING_IDX, it means this tx request is head of
149 * one or more merged tx requests, otherwise it is the continuation of
150 * previous tx request.
151 */
152 static inline int pending_tx_is_head(struct xen_netbk *netbk, RING_IDX idx)
153 {
154 return netbk->pending_tx_info[idx].head != INVALID_PENDING_RING_IDX;
155 }
156
157 void xen_netbk_add_xenvif(struct xenvif *vif)
158 {
159 int i;
160 int min_netfront_count;
161 int min_group = 0;
162 struct xen_netbk *netbk;
163
164 min_netfront_count = atomic_read(&xen_netbk[0].netfront_count);
165 for (i = 0; i < xen_netbk_group_nr; i++) {
166 int netfront_count = atomic_read(&xen_netbk[i].netfront_count);
167 if (netfront_count < min_netfront_count) {
168 min_group = i;
169 min_netfront_count = netfront_count;
170 }
171 }
172
173 netbk = &xen_netbk[min_group];
174
175 vif->netbk = netbk;
176 atomic_inc(&netbk->netfront_count);
177 }
178
179 void xen_netbk_remove_xenvif(struct xenvif *vif)
180 {
181 struct xen_netbk *netbk = vif->netbk;
182 vif->netbk = NULL;
183 atomic_dec(&netbk->netfront_count);
184 }
185
186 static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx,
187 u8 status);
188 static void make_tx_response(struct xenvif *vif,
189 struct xen_netif_tx_request *txp,
190 s8 st);
191 static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
192 u16 id,
193 s8 st,
194 u16 offset,
195 u16 size,
196 u16 flags);
197
198 static inline unsigned long idx_to_pfn(struct xen_netbk *netbk,
199 u16 idx)
200 {
201 return page_to_pfn(netbk->mmap_pages[idx]);
202 }
203
204 static inline unsigned long idx_to_kaddr(struct xen_netbk *netbk,
205 u16 idx)
206 {
207 return (unsigned long)pfn_to_kaddr(idx_to_pfn(netbk, idx));
208 }
209
210 /* extra field used in struct page */
211 static inline void set_page_ext(struct page *pg, struct xen_netbk *netbk,
212 unsigned int idx)
213 {
214 unsigned int group = netbk - xen_netbk;
215 union page_ext ext = { .e = { .group = group + 1, .idx = idx } };
216
217 BUILD_BUG_ON(sizeof(ext) > sizeof(ext.mapping));
218 pg->mapping = ext.mapping;
219 }
220
221 static int get_page_ext(struct page *pg,
222 unsigned int *pgroup, unsigned int *pidx)
223 {
224 union page_ext ext = { .mapping = pg->mapping };
225 struct xen_netbk *netbk;
226 unsigned int group, idx;
227
228 group = ext.e.group - 1;
229
230 if (group < 0 || group >= xen_netbk_group_nr)
231 return 0;
232
233 netbk = &xen_netbk[group];
234
235 idx = ext.e.idx;
236
237 if ((idx < 0) || (idx >= MAX_PENDING_REQS))
238 return 0;
239
240 if (netbk->mmap_pages[idx] != pg)
241 return 0;
242
243 *pgroup = group;
244 *pidx = idx;
245
246 return 1;
247 }
248
249 /*
250 * This is the amount of packet we copy rather than map, so that the
251 * guest can't fiddle with the contents of the headers while we do
252 * packet processing on them (netfilter, routing, etc).
253 */
254 #define PKT_PROT_LEN (ETH_HLEN + \
255 VLAN_HLEN + \
256 sizeof(struct iphdr) + MAX_IPOPTLEN + \
257 sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE)
258
259 static u16 frag_get_pending_idx(skb_frag_t *frag)
260 {
261 return (u16)frag->page_offset;
262 }
263
264 static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
265 {
266 frag->page_offset = pending_idx;
267 }
268
269 static inline pending_ring_idx_t pending_index(unsigned i)
270 {
271 return i & (MAX_PENDING_REQS-1);
272 }
273
274 static inline pending_ring_idx_t nr_pending_reqs(struct xen_netbk *netbk)
275 {
276 return MAX_PENDING_REQS -
277 netbk->pending_prod + netbk->pending_cons;
278 }
279
280 static void xen_netbk_kick_thread(struct xen_netbk *netbk)
281 {
282 wake_up(&netbk->wq);
283 }
284
285 static int max_required_rx_slots(struct xenvif *vif)
286 {
287 int max = DIV_ROUND_UP(vif->dev->mtu, PAGE_SIZE);
288
289 /* XXX FIXME: RX path dependent on MAX_SKB_FRAGS */
290 if (vif->can_sg || vif->gso || vif->gso_prefix)
291 max += MAX_SKB_FRAGS + 1; /* extra_info + frags */
292
293 return max;
294 }
295
296 int xen_netbk_rx_ring_full(struct xenvif *vif)
297 {
298 RING_IDX peek = vif->rx_req_cons_peek;
299 RING_IDX needed = max_required_rx_slots(vif);
300
301 return ((vif->rx.sring->req_prod - peek) < needed) ||
302 ((vif->rx.rsp_prod_pvt + XEN_NETIF_RX_RING_SIZE - peek) < needed);
303 }
304
305 int xen_netbk_must_stop_queue(struct xenvif *vif)
306 {
307 if (!xen_netbk_rx_ring_full(vif))
308 return 0;
309
310 vif->rx.sring->req_event = vif->rx_req_cons_peek +
311 max_required_rx_slots(vif);
312 mb(); /* request notification /then/ check the queue */
313
314 return xen_netbk_rx_ring_full(vif);
315 }
316
317 /*
318 * Returns true if we should start a new receive buffer instead of
319 * adding 'size' bytes to a buffer which currently contains 'offset'
320 * bytes.
321 */
322 static bool start_new_rx_buffer(int offset, unsigned long size, int head)
323 {
324 /* simple case: we have completely filled the current buffer. */
325 if (offset == MAX_BUFFER_OFFSET)
326 return true;
327
328 /*
329 * complex case: start a fresh buffer if the current frag
330 * would overflow the current buffer but only if:
331 * (i) this frag would fit completely in the next buffer
332 * and (ii) there is already some data in the current buffer
333 * and (iii) this is not the head buffer.
334 *
335 * Where:
336 * - (i) stops us splitting a frag into two copies
337 * unless the frag is too large for a single buffer.
338 * - (ii) stops us from leaving a buffer pointlessly empty.
339 * - (iii) stops us leaving the first buffer
340 * empty. Strictly speaking this is already covered
341 * by (ii) but is explicitly checked because
342 * netfront relies on the first buffer being
343 * non-empty and can crash otherwise.
344 *
345 * This means we will effectively linearise small
346 * frags but do not needlessly split large buffers
347 * into multiple copies tend to give large frags their
348 * own buffers as before.
349 */
350 if ((offset + size > MAX_BUFFER_OFFSET) &&
351 (size <= MAX_BUFFER_OFFSET) && offset && !head)
352 return true;
353
354 return false;
355 }
356
357 /*
358 * Figure out how many ring slots we're going to need to send @skb to
359 * the guest. This function is essentially a dry run of
360 * netbk_gop_frag_copy.
361 */
362 unsigned int xen_netbk_count_skb_slots(struct xenvif *vif, struct sk_buff *skb)
363 {
364 unsigned int count;
365 int i, copy_off;
366
367 count = DIV_ROUND_UP(skb_headlen(skb), PAGE_SIZE);
368
369 copy_off = skb_headlen(skb) % PAGE_SIZE;
370
371 if (skb_shinfo(skb)->gso_size)
372 count++;
373
374 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
375 unsigned long size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
376 unsigned long offset = skb_shinfo(skb)->frags[i].page_offset;
377 unsigned long bytes;
378
379 offset &= ~PAGE_MASK;
380
381 while (size > 0) {
382 BUG_ON(offset >= PAGE_SIZE);
383 BUG_ON(copy_off > MAX_BUFFER_OFFSET);
384
385 bytes = PAGE_SIZE - offset;
386
387 if (bytes > size)
388 bytes = size;
389
390 if (start_new_rx_buffer(copy_off, bytes, 0)) {
391 count++;
392 copy_off = 0;
393 }
394
395 if (copy_off + bytes > MAX_BUFFER_OFFSET)
396 bytes = MAX_BUFFER_OFFSET - copy_off;
397
398 copy_off += bytes;
399
400 offset += bytes;
401 size -= bytes;
402
403 if (offset == PAGE_SIZE)
404 offset = 0;
405 }
406 }
407 return count;
408 }
409
410 struct netrx_pending_operations {
411 unsigned copy_prod, copy_cons;
412 unsigned meta_prod, meta_cons;
413 struct gnttab_copy *copy;
414 struct netbk_rx_meta *meta;
415 int copy_off;
416 grant_ref_t copy_gref;
417 };
418
419 static struct netbk_rx_meta *get_next_rx_buffer(struct xenvif *vif,
420 struct netrx_pending_operations *npo)
421 {
422 struct netbk_rx_meta *meta;
423 struct xen_netif_rx_request *req;
424
425 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
426
427 meta = npo->meta + npo->meta_prod++;
428 meta->gso_size = 0;
429 meta->size = 0;
430 meta->id = req->id;
431
432 npo->copy_off = 0;
433 npo->copy_gref = req->gref;
434
435 return meta;
436 }
437
438 /*
439 * Set up the grant operations for this fragment. If it's a flipping
440 * interface, we also set up the unmap request from here.
441 */
442 static void netbk_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb,
443 struct netrx_pending_operations *npo,
444 struct page *page, unsigned long size,
445 unsigned long offset, int *head)
446 {
447 struct gnttab_copy *copy_gop;
448 struct netbk_rx_meta *meta;
449 /*
450 * These variables are used iff get_page_ext returns true,
451 * in which case they are guaranteed to be initialized.
452 */
453 unsigned int uninitialized_var(group), uninitialized_var(idx);
454 int foreign = get_page_ext(page, &group, &idx);
455 unsigned long bytes;
456
457 /* Data must not cross a page boundary. */
458 BUG_ON(size + offset > PAGE_SIZE<<compound_order(page));
459
460 meta = npo->meta + npo->meta_prod - 1;
461
462 /* Skip unused frames from start of page */
463 page += offset >> PAGE_SHIFT;
464 offset &= ~PAGE_MASK;
465
466 while (size > 0) {
467 BUG_ON(offset >= PAGE_SIZE);
468 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
469
470 bytes = PAGE_SIZE - offset;
471
472 if (bytes > size)
473 bytes = size;
474
475 if (start_new_rx_buffer(npo->copy_off, bytes, *head)) {
476 /*
477 * Netfront requires there to be some data in the head
478 * buffer.
479 */
480 BUG_ON(*head);
481
482 meta = get_next_rx_buffer(vif, npo);
483 }
484
485 if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
486 bytes = MAX_BUFFER_OFFSET - npo->copy_off;
487
488 copy_gop = npo->copy + npo->copy_prod++;
489 copy_gop->flags = GNTCOPY_dest_gref;
490 if (foreign) {
491 struct xen_netbk *netbk = &xen_netbk[group];
492 struct pending_tx_info *src_pend;
493
494 src_pend = &netbk->pending_tx_info[idx];
495
496 copy_gop->source.domid = src_pend->vif->domid;
497 copy_gop->source.u.ref = src_pend->req.gref;
498 copy_gop->flags |= GNTCOPY_source_gref;
499 } else {
500 void *vaddr = page_address(page);
501 copy_gop->source.domid = DOMID_SELF;
502 copy_gop->source.u.gmfn = virt_to_mfn(vaddr);
503 }
504 copy_gop->source.offset = offset;
505 copy_gop->dest.domid = vif->domid;
506
507 copy_gop->dest.offset = npo->copy_off;
508 copy_gop->dest.u.ref = npo->copy_gref;
509 copy_gop->len = bytes;
510
511 npo->copy_off += bytes;
512 meta->size += bytes;
513
514 offset += bytes;
515 size -= bytes;
516
517 /* Next frame */
518 if (offset == PAGE_SIZE && size) {
519 BUG_ON(!PageCompound(page));
520 page++;
521 offset = 0;
522 }
523
524 /* Leave a gap for the GSO descriptor. */
525 if (*head && skb_shinfo(skb)->gso_size && !vif->gso_prefix)
526 vif->rx.req_cons++;
527
528 *head = 0; /* There must be something in this buffer now. */
529
530 }
531 }
532
533 /*
534 * Prepare an SKB to be transmitted to the frontend.
535 *
536 * This function is responsible for allocating grant operations, meta
537 * structures, etc.
538 *
539 * It returns the number of meta structures consumed. The number of
540 * ring slots used is always equal to the number of meta slots used
541 * plus the number of GSO descriptors used. Currently, we use either
542 * zero GSO descriptors (for non-GSO packets) or one descriptor (for
543 * frontend-side LRO).
544 */
545 static int netbk_gop_skb(struct sk_buff *skb,
546 struct netrx_pending_operations *npo)
547 {
548 struct xenvif *vif = netdev_priv(skb->dev);
549 int nr_frags = skb_shinfo(skb)->nr_frags;
550 int i;
551 struct xen_netif_rx_request *req;
552 struct netbk_rx_meta *meta;
553 unsigned char *data;
554 int head = 1;
555 int old_meta_prod;
556
557 old_meta_prod = npo->meta_prod;
558
559 /* Set up a GSO prefix descriptor, if necessary */
560 if (skb_shinfo(skb)->gso_size && vif->gso_prefix) {
561 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
562 meta = npo->meta + npo->meta_prod++;
563 meta->gso_size = skb_shinfo(skb)->gso_size;
564 meta->size = 0;
565 meta->id = req->id;
566 }
567
568 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
569 meta = npo->meta + npo->meta_prod++;
570
571 if (!vif->gso_prefix)
572 meta->gso_size = skb_shinfo(skb)->gso_size;
573 else
574 meta->gso_size = 0;
575
576 meta->size = 0;
577 meta->id = req->id;
578 npo->copy_off = 0;
579 npo->copy_gref = req->gref;
580
581 data = skb->data;
582 while (data < skb_tail_pointer(skb)) {
583 unsigned int offset = offset_in_page(data);
584 unsigned int len = PAGE_SIZE - offset;
585
586 if (data + len > skb_tail_pointer(skb))
587 len = skb_tail_pointer(skb) - data;
588
589 netbk_gop_frag_copy(vif, skb, npo,
590 virt_to_page(data), len, offset, &head);
591 data += len;
592 }
593
594 for (i = 0; i < nr_frags; i++) {
595 netbk_gop_frag_copy(vif, skb, npo,
596 skb_frag_page(&skb_shinfo(skb)->frags[i]),
597 skb_frag_size(&skb_shinfo(skb)->frags[i]),
598 skb_shinfo(skb)->frags[i].page_offset,
599 &head);
600 }
601
602 return npo->meta_prod - old_meta_prod;
603 }
604
605 /*
606 * This is a twin to netbk_gop_skb. Assume that netbk_gop_skb was
607 * used to set up the operations on the top of
608 * netrx_pending_operations, which have since been done. Check that
609 * they didn't give any errors and advance over them.
610 */
611 static int netbk_check_gop(struct xenvif *vif, int nr_meta_slots,
612 struct netrx_pending_operations *npo)
613 {
614 struct gnttab_copy *copy_op;
615 int status = XEN_NETIF_RSP_OKAY;
616 int i;
617
618 for (i = 0; i < nr_meta_slots; i++) {
619 copy_op = npo->copy + npo->copy_cons++;
620 if (copy_op->status != GNTST_okay) {
621 netdev_dbg(vif->dev,
622 "Bad status %d from copy to DOM%d.\n",
623 copy_op->status, vif->domid);
624 status = XEN_NETIF_RSP_ERROR;
625 }
626 }
627
628 return status;
629 }
630
631 static void netbk_add_frag_responses(struct xenvif *vif, int status,
632 struct netbk_rx_meta *meta,
633 int nr_meta_slots)
634 {
635 int i;
636 unsigned long offset;
637
638 /* No fragments used */
639 if (nr_meta_slots <= 1)
640 return;
641
642 nr_meta_slots--;
643
644 for (i = 0; i < nr_meta_slots; i++) {
645 int flags;
646 if (i == nr_meta_slots - 1)
647 flags = 0;
648 else
649 flags = XEN_NETRXF_more_data;
650
651 offset = 0;
652 make_rx_response(vif, meta[i].id, status, offset,
653 meta[i].size, flags);
654 }
655 }
656
657 struct skb_cb_overlay {
658 int meta_slots_used;
659 };
660
661 static void xen_netbk_rx_action(struct xen_netbk *netbk)
662 {
663 struct xenvif *vif = NULL, *tmp;
664 s8 status;
665 u16 flags;
666 struct xen_netif_rx_response *resp;
667 struct sk_buff_head rxq;
668 struct sk_buff *skb;
669 LIST_HEAD(notify);
670 int ret;
671 int nr_frags;
672 int count;
673 unsigned long offset;
674 struct skb_cb_overlay *sco;
675
676 struct netrx_pending_operations npo = {
677 .copy = netbk->grant_copy_op,
678 .meta = netbk->meta,
679 };
680
681 skb_queue_head_init(&rxq);
682
683 count = 0;
684
685 while ((skb = skb_dequeue(&netbk->rx_queue)) != NULL) {
686 vif = netdev_priv(skb->dev);
687 nr_frags = skb_shinfo(skb)->nr_frags;
688
689 sco = (struct skb_cb_overlay *)skb->cb;
690 sco->meta_slots_used = netbk_gop_skb(skb, &npo);
691
692 count += nr_frags + 1;
693
694 __skb_queue_tail(&rxq, skb);
695
696 /* Filled the batch queue? */
697 /* XXX FIXME: RX path dependent on MAX_SKB_FRAGS */
698 if (count + MAX_SKB_FRAGS >= XEN_NETIF_RX_RING_SIZE)
699 break;
700 }
701
702 BUG_ON(npo.meta_prod > ARRAY_SIZE(netbk->meta));
703
704 if (!npo.copy_prod)
705 return;
706
707 BUG_ON(npo.copy_prod > ARRAY_SIZE(netbk->grant_copy_op));
708 gnttab_batch_copy(netbk->grant_copy_op, npo.copy_prod);
709
710 while ((skb = __skb_dequeue(&rxq)) != NULL) {
711 sco = (struct skb_cb_overlay *)skb->cb;
712
713 vif = netdev_priv(skb->dev);
714
715 if (netbk->meta[npo.meta_cons].gso_size && vif->gso_prefix) {
716 resp = RING_GET_RESPONSE(&vif->rx,
717 vif->rx.rsp_prod_pvt++);
718
719 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
720
721 resp->offset = netbk->meta[npo.meta_cons].gso_size;
722 resp->id = netbk->meta[npo.meta_cons].id;
723 resp->status = sco->meta_slots_used;
724
725 npo.meta_cons++;
726 sco->meta_slots_used--;
727 }
728
729
730 vif->dev->stats.tx_bytes += skb->len;
731 vif->dev->stats.tx_packets++;
732
733 status = netbk_check_gop(vif, sco->meta_slots_used, &npo);
734
735 if (sco->meta_slots_used == 1)
736 flags = 0;
737 else
738 flags = XEN_NETRXF_more_data;
739
740 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
741 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
742 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
743 /* remote but checksummed. */
744 flags |= XEN_NETRXF_data_validated;
745
746 offset = 0;
747 resp = make_rx_response(vif, netbk->meta[npo.meta_cons].id,
748 status, offset,
749 netbk->meta[npo.meta_cons].size,
750 flags);
751
752 if (netbk->meta[npo.meta_cons].gso_size && !vif->gso_prefix) {
753 struct xen_netif_extra_info *gso =
754 (struct xen_netif_extra_info *)
755 RING_GET_RESPONSE(&vif->rx,
756 vif->rx.rsp_prod_pvt++);
757
758 resp->flags |= XEN_NETRXF_extra_info;
759
760 gso->u.gso.size = netbk->meta[npo.meta_cons].gso_size;
761 gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
762 gso->u.gso.pad = 0;
763 gso->u.gso.features = 0;
764
765 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
766 gso->flags = 0;
767 }
768
769 netbk_add_frag_responses(vif, status,
770 netbk->meta + npo.meta_cons + 1,
771 sco->meta_slots_used);
772
773 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret);
774
775 xenvif_notify_tx_completion(vif);
776
777 if (ret && list_empty(&vif->notify_list))
778 list_add_tail(&vif->notify_list, &notify);
779 else
780 xenvif_put(vif);
781 npo.meta_cons += sco->meta_slots_used;
782 dev_kfree_skb(skb);
783 }
784
785 list_for_each_entry_safe(vif, tmp, &notify, notify_list) {
786 notify_remote_via_irq(vif->irq);
787 list_del_init(&vif->notify_list);
788 xenvif_put(vif);
789 }
790
791 /* More work to do? */
792 if (!skb_queue_empty(&netbk->rx_queue) &&
793 !timer_pending(&netbk->net_timer))
794 xen_netbk_kick_thread(netbk);
795 }
796
797 void xen_netbk_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb)
798 {
799 struct xen_netbk *netbk = vif->netbk;
800
801 skb_queue_tail(&netbk->rx_queue, skb);
802
803 xen_netbk_kick_thread(netbk);
804 }
805
806 static void xen_netbk_alarm(unsigned long data)
807 {
808 struct xen_netbk *netbk = (struct xen_netbk *)data;
809 xen_netbk_kick_thread(netbk);
810 }
811
812 static int __on_net_schedule_list(struct xenvif *vif)
813 {
814 return !list_empty(&vif->schedule_list);
815 }
816
817 /* Must be called with net_schedule_list_lock held */
818 static void remove_from_net_schedule_list(struct xenvif *vif)
819 {
820 if (likely(__on_net_schedule_list(vif))) {
821 list_del_init(&vif->schedule_list);
822 xenvif_put(vif);
823 }
824 }
825
826 static struct xenvif *poll_net_schedule_list(struct xen_netbk *netbk)
827 {
828 struct xenvif *vif = NULL;
829
830 spin_lock_irq(&netbk->net_schedule_list_lock);
831 if (list_empty(&netbk->net_schedule_list))
832 goto out;
833
834 vif = list_first_entry(&netbk->net_schedule_list,
835 struct xenvif, schedule_list);
836 if (!vif)
837 goto out;
838
839 xenvif_get(vif);
840
841 remove_from_net_schedule_list(vif);
842 out:
843 spin_unlock_irq(&netbk->net_schedule_list_lock);
844 return vif;
845 }
846
847 void xen_netbk_schedule_xenvif(struct xenvif *vif)
848 {
849 unsigned long flags;
850 struct xen_netbk *netbk = vif->netbk;
851
852 if (__on_net_schedule_list(vif))
853 goto kick;
854
855 spin_lock_irqsave(&netbk->net_schedule_list_lock, flags);
856 if (!__on_net_schedule_list(vif) &&
857 likely(xenvif_schedulable(vif))) {
858 list_add_tail(&vif->schedule_list, &netbk->net_schedule_list);
859 xenvif_get(vif);
860 }
861 spin_unlock_irqrestore(&netbk->net_schedule_list_lock, flags);
862
863 kick:
864 smp_mb();
865 if ((nr_pending_reqs(netbk) < (MAX_PENDING_REQS/2)) &&
866 !list_empty(&netbk->net_schedule_list))
867 xen_netbk_kick_thread(netbk);
868 }
869
870 void xen_netbk_deschedule_xenvif(struct xenvif *vif)
871 {
872 struct xen_netbk *netbk = vif->netbk;
873 spin_lock_irq(&netbk->net_schedule_list_lock);
874 remove_from_net_schedule_list(vif);
875 spin_unlock_irq(&netbk->net_schedule_list_lock);
876 }
877
878 void xen_netbk_check_rx_xenvif(struct xenvif *vif)
879 {
880 int more_to_do;
881
882 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
883
884 if (more_to_do)
885 xen_netbk_schedule_xenvif(vif);
886 }
887
888 static void tx_add_credit(struct xenvif *vif)
889 {
890 unsigned long max_burst, max_credit;
891
892 /*
893 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
894 * Otherwise the interface can seize up due to insufficient credit.
895 */
896 max_burst = RING_GET_REQUEST(&vif->tx, vif->tx.req_cons)->size;
897 max_burst = min(max_burst, 131072UL);
898 max_burst = max(max_burst, vif->credit_bytes);
899
900 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
901 max_credit = vif->remaining_credit + vif->credit_bytes;
902 if (max_credit < vif->remaining_credit)
903 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
904
905 vif->remaining_credit = min(max_credit, max_burst);
906 }
907
908 static void tx_credit_callback(unsigned long data)
909 {
910 struct xenvif *vif = (struct xenvif *)data;
911 tx_add_credit(vif);
912 xen_netbk_check_rx_xenvif(vif);
913 }
914
915 static void netbk_tx_err(struct xenvif *vif,
916 struct xen_netif_tx_request *txp, RING_IDX end)
917 {
918 RING_IDX cons = vif->tx.req_cons;
919
920 do {
921 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
922 if (cons == end)
923 break;
924 txp = RING_GET_REQUEST(&vif->tx, cons++);
925 } while (1);
926 vif->tx.req_cons = cons;
927 xen_netbk_check_rx_xenvif(vif);
928 xenvif_put(vif);
929 }
930
931 static void netbk_fatal_tx_err(struct xenvif *vif)
932 {
933 netdev_err(vif->dev, "fatal error; disabling device\n");
934 xenvif_carrier_off(vif);
935 xenvif_put(vif);
936 }
937
938 static int netbk_count_requests(struct xenvif *vif,
939 struct xen_netif_tx_request *first,
940 struct xen_netif_tx_request *txp,
941 int work_to_do)
942 {
943 RING_IDX cons = vif->tx.req_cons;
944 int slots = 0;
945 int drop_err = 0;
946 int more_data;
947
948 if (!(first->flags & XEN_NETTXF_more_data))
949 return 0;
950
951 do {
952 struct xen_netif_tx_request dropped_tx = { 0 };
953
954 if (slots >= work_to_do) {
955 netdev_err(vif->dev,
956 "Asked for %d slots but exceeds this limit\n",
957 work_to_do);
958 netbk_fatal_tx_err(vif);
959 return -ENODATA;
960 }
961
962 /* This guest is really using too many slots and
963 * considered malicious.
964 */
965 if (unlikely(slots >= fatal_skb_slots)) {
966 netdev_err(vif->dev,
967 "Malicious frontend using %d slots, threshold %u\n",
968 slots, fatal_skb_slots);
969 netbk_fatal_tx_err(vif);
970 return -E2BIG;
971 }
972
973 /* Xen network protocol had implicit dependency on
974 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
975 * the historical MAX_SKB_FRAGS value 18 to honor the
976 * same behavior as before. Any packet using more than
977 * 18 slots but less than fatal_skb_slots slots is
978 * dropped
979 */
980 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
981 if (net_ratelimit())
982 netdev_dbg(vif->dev,
983 "Too many slots (%d) exceeding limit (%d), dropping packet\n",
984 slots, XEN_NETBK_LEGACY_SLOTS_MAX);
985 drop_err = -E2BIG;
986 }
987
988 if (drop_err)
989 txp = &dropped_tx;
990
991 memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + slots),
992 sizeof(*txp));
993
994 /* If the guest submitted a frame >= 64 KiB then
995 * first->size overflowed and following slots will
996 * appear to be larger than the frame.
997 *
998 * This cannot be fatal error as there are buggy
999 * frontends that do this.
1000 *
1001 * Consume all slots and drop the packet.
1002 */
1003 if (!drop_err && txp->size > first->size) {
1004 if (net_ratelimit())
1005 netdev_dbg(vif->dev,
1006 "Invalid tx request, slot size %u > remaining size %u\n",
1007 txp->size, first->size);
1008 drop_err = -EIO;
1009 }
1010
1011 first->size -= txp->size;
1012 slots++;
1013
1014 if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
1015 netdev_err(vif->dev, "Cross page boundary, txp->offset: %x, size: %u\n",
1016 txp->offset, txp->size);
1017 netbk_fatal_tx_err(vif);
1018 return -EINVAL;
1019 }
1020
1021 more_data = txp->flags & XEN_NETTXF_more_data;
1022
1023 if (!drop_err)
1024 txp++;
1025
1026 } while (more_data);
1027
1028 if (drop_err) {
1029 netbk_tx_err(vif, first, cons + slots);
1030 return drop_err;
1031 }
1032
1033 return slots;
1034 }
1035
1036 static struct page *xen_netbk_alloc_page(struct xen_netbk *netbk,
1037 u16 pending_idx)
1038 {
1039 struct page *page;
1040 page = alloc_page(GFP_KERNEL|__GFP_COLD);
1041 if (!page)
1042 return NULL;
1043 set_page_ext(page, netbk, pending_idx);
1044 netbk->mmap_pages[pending_idx] = page;
1045 return page;
1046 }
1047
1048 static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
1049 struct xenvif *vif,
1050 struct sk_buff *skb,
1051 struct xen_netif_tx_request *txp,
1052 struct gnttab_copy *gop)
1053 {
1054 struct skb_shared_info *shinfo = skb_shinfo(skb);
1055 skb_frag_t *frags = shinfo->frags;
1056 u16 pending_idx = *((u16 *)skb->data);
1057 u16 head_idx = 0;
1058 int slot, start;
1059 struct page *page;
1060 pending_ring_idx_t index, start_idx = 0;
1061 uint16_t dst_offset;
1062 unsigned int nr_slots;
1063 struct pending_tx_info *first = NULL;
1064
1065 /* At this point shinfo->nr_frags is in fact the number of
1066 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
1067 */
1068 nr_slots = shinfo->nr_frags;
1069
1070 /* Skip first skb fragment if it is on same page as header fragment. */
1071 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
1072
1073 /* Coalesce tx requests, at this point the packet passed in
1074 * should be <= 64K. Any packets larger than 64K have been
1075 * handled in netbk_count_requests().
1076 */
1077 for (shinfo->nr_frags = slot = start; slot < nr_slots;
1078 shinfo->nr_frags++) {
1079 struct pending_tx_info *pending_tx_info =
1080 netbk->pending_tx_info;
1081
1082 page = alloc_page(GFP_KERNEL|__GFP_COLD);
1083 if (!page)
1084 goto err;
1085
1086 dst_offset = 0;
1087 first = NULL;
1088 while (dst_offset < PAGE_SIZE && slot < nr_slots) {
1089 gop->flags = GNTCOPY_source_gref;
1090
1091 gop->source.u.ref = txp->gref;
1092 gop->source.domid = vif->domid;
1093 gop->source.offset = txp->offset;
1094
1095 gop->dest.domid = DOMID_SELF;
1096
1097 gop->dest.offset = dst_offset;
1098 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
1099
1100 if (dst_offset + txp->size > PAGE_SIZE) {
1101 /* This page can only merge a portion
1102 * of tx request. Do not increment any
1103 * pointer / counter here. The txp
1104 * will be dealt with in future
1105 * rounds, eventually hitting the
1106 * `else` branch.
1107 */
1108 gop->len = PAGE_SIZE - dst_offset;
1109 txp->offset += gop->len;
1110 txp->size -= gop->len;
1111 dst_offset += gop->len; /* quit loop */
1112 } else {
1113 /* This tx request can be merged in the page */
1114 gop->len = txp->size;
1115 dst_offset += gop->len;
1116
1117 index = pending_index(netbk->pending_cons++);
1118
1119 pending_idx = netbk->pending_ring[index];
1120
1121 memcpy(&pending_tx_info[pending_idx].req, txp,
1122 sizeof(*txp));
1123 xenvif_get(vif);
1124
1125 pending_tx_info[pending_idx].vif = vif;
1126
1127 /* Poison these fields, corresponding
1128 * fields for head tx req will be set
1129 * to correct values after the loop.
1130 */
1131 netbk->mmap_pages[pending_idx] = (void *)(~0UL);
1132 pending_tx_info[pending_idx].head =
1133 INVALID_PENDING_RING_IDX;
1134
1135 if (!first) {
1136 first = &pending_tx_info[pending_idx];
1137 start_idx = index;
1138 head_idx = pending_idx;
1139 }
1140
1141 txp++;
1142 slot++;
1143 }
1144
1145 gop++;
1146 }
1147
1148 first->req.offset = 0;
1149 first->req.size = dst_offset;
1150 first->head = start_idx;
1151 set_page_ext(page, netbk, head_idx);
1152 netbk->mmap_pages[head_idx] = page;
1153 frag_set_pending_idx(&frags[shinfo->nr_frags], head_idx);
1154 }
1155
1156 BUG_ON(shinfo->nr_frags > MAX_SKB_FRAGS);
1157
1158 return gop;
1159 err:
1160 /* Unwind, freeing all pages and sending error responses. */
1161 while (shinfo->nr_frags-- > start) {
1162 xen_netbk_idx_release(netbk,
1163 frag_get_pending_idx(&frags[shinfo->nr_frags]),
1164 XEN_NETIF_RSP_ERROR);
1165 }
1166 /* The head too, if necessary. */
1167 if (start)
1168 xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);
1169
1170 return NULL;
1171 }
1172
1173 static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
1174 struct sk_buff *skb,
1175 struct gnttab_copy **gopp)
1176 {
1177 struct gnttab_copy *gop = *gopp;
1178 u16 pending_idx = *((u16 *)skb->data);
1179 struct skb_shared_info *shinfo = skb_shinfo(skb);
1180 struct pending_tx_info *tx_info;
1181 int nr_frags = shinfo->nr_frags;
1182 int i, err, start;
1183 u16 peek; /* peek into next tx request */
1184
1185 /* Check status of header. */
1186 err = gop->status;
1187 if (unlikely(err))
1188 xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);
1189
1190 /* Skip first skb fragment if it is on same page as header fragment. */
1191 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
1192
1193 for (i = start; i < nr_frags; i++) {
1194 int j, newerr;
1195 pending_ring_idx_t head;
1196
1197 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
1198 tx_info = &netbk->pending_tx_info[pending_idx];
1199 head = tx_info->head;
1200
1201 /* Check error status: if okay then remember grant handle. */
1202 do {
1203 newerr = (++gop)->status;
1204 if (newerr)
1205 break;
1206 peek = netbk->pending_ring[pending_index(++head)];
1207 } while (!pending_tx_is_head(netbk, peek));
1208
1209 if (likely(!newerr)) {
1210 /* Had a previous error? Invalidate this fragment. */
1211 if (unlikely(err))
1212 xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
1213 continue;
1214 }
1215
1216 /* Error on this fragment: respond to client with an error. */
1217 xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);
1218
1219 /* Not the first error? Preceding frags already invalidated. */
1220 if (err)
1221 continue;
1222
1223 /* First error: invalidate header and preceding fragments. */
1224 pending_idx = *((u16 *)skb->data);
1225 xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
1226 for (j = start; j < i; j++) {
1227 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
1228 xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
1229 }
1230
1231 /* Remember the error: invalidate all subsequent fragments. */
1232 err = newerr;
1233 }
1234
1235 *gopp = gop + 1;
1236 return err;
1237 }
1238
1239 static void xen_netbk_fill_frags(struct xen_netbk *netbk, struct sk_buff *skb)
1240 {
1241 struct skb_shared_info *shinfo = skb_shinfo(skb);
1242 int nr_frags = shinfo->nr_frags;
1243 int i;
1244
1245 for (i = 0; i < nr_frags; i++) {
1246 skb_frag_t *frag = shinfo->frags + i;
1247 struct xen_netif_tx_request *txp;
1248 struct page *page;
1249 u16 pending_idx;
1250
1251 pending_idx = frag_get_pending_idx(frag);
1252
1253 txp = &netbk->pending_tx_info[pending_idx].req;
1254 page = virt_to_page(idx_to_kaddr(netbk, pending_idx));
1255 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
1256 skb->len += txp->size;
1257 skb->data_len += txp->size;
1258 skb->truesize += txp->size;
1259
1260 /* Take an extra reference to offset xen_netbk_idx_release */
1261 get_page(netbk->mmap_pages[pending_idx]);
1262 xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
1263 }
1264 }
1265
1266 static int xen_netbk_get_extras(struct xenvif *vif,
1267 struct xen_netif_extra_info *extras,
1268 int work_to_do)
1269 {
1270 struct xen_netif_extra_info extra;
1271 RING_IDX cons = vif->tx.req_cons;
1272
1273 do {
1274 if (unlikely(work_to_do-- <= 0)) {
1275 netdev_err(vif->dev, "Missing extra info\n");
1276 netbk_fatal_tx_err(vif);
1277 return -EBADR;
1278 }
1279
1280 memcpy(&extra, RING_GET_REQUEST(&vif->tx, cons),
1281 sizeof(extra));
1282 if (unlikely(!extra.type ||
1283 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1284 vif->tx.req_cons = ++cons;
1285 netdev_err(vif->dev,
1286 "Invalid extra type: %d\n", extra.type);
1287 netbk_fatal_tx_err(vif);
1288 return -EINVAL;
1289 }
1290
1291 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1292 vif->tx.req_cons = ++cons;
1293 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1294
1295 return work_to_do;
1296 }
1297
1298 static int netbk_set_skb_gso(struct xenvif *vif,
1299 struct sk_buff *skb,
1300 struct xen_netif_extra_info *gso)
1301 {
1302 if (!gso->u.gso.size) {
1303 netdev_err(vif->dev, "GSO size must not be zero.\n");
1304 netbk_fatal_tx_err(vif);
1305 return -EINVAL;
1306 }
1307
1308 /* Currently only TCPv4 S.O. is supported. */
1309 if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
1310 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1311 netbk_fatal_tx_err(vif);
1312 return -EINVAL;
1313 }
1314
1315 skb_shinfo(skb)->gso_size = gso->u.gso.size;
1316 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1317
1318 /* Header must be checked, and gso_segs computed. */
1319 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1320 skb_shinfo(skb)->gso_segs = 0;
1321
1322 return 0;
1323 }
1324
1325 static int checksum_setup(struct xenvif *vif, struct sk_buff *skb)
1326 {
1327 struct iphdr *iph;
1328 int err = -EPROTO;
1329 int recalculate_partial_csum = 0;
1330
1331 /*
1332 * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1333 * peers can fail to set NETRXF_csum_blank when sending a GSO
1334 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1335 * recalculate the partial checksum.
1336 */
1337 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1338 vif->rx_gso_checksum_fixup++;
1339 skb->ip_summed = CHECKSUM_PARTIAL;
1340 recalculate_partial_csum = 1;
1341 }
1342
1343 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1344 if (skb->ip_summed != CHECKSUM_PARTIAL)
1345 return 0;
1346
1347 if (skb->protocol != htons(ETH_P_IP))
1348 goto out;
1349
1350 iph = (void *)skb->data;
1351 switch (iph->protocol) {
1352 case IPPROTO_TCP:
1353 if (!skb_partial_csum_set(skb, 4 * iph->ihl,
1354 offsetof(struct tcphdr, check)))
1355 goto out;
1356
1357 if (recalculate_partial_csum) {
1358 struct tcphdr *tcph = tcp_hdr(skb);
1359 tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1360 skb->len - iph->ihl*4,
1361 IPPROTO_TCP, 0);
1362 }
1363 break;
1364 case IPPROTO_UDP:
1365 if (!skb_partial_csum_set(skb, 4 * iph->ihl,
1366 offsetof(struct udphdr, check)))
1367 goto out;
1368
1369 if (recalculate_partial_csum) {
1370 struct udphdr *udph = udp_hdr(skb);
1371 udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1372 skb->len - iph->ihl*4,
1373 IPPROTO_UDP, 0);
1374 }
1375 break;
1376 default:
1377 if (net_ratelimit())
1378 netdev_err(vif->dev,
1379 "Attempting to checksum a non-TCP/UDP packet, dropping a protocol %d packet\n",
1380 iph->protocol);
1381 goto out;
1382 }
1383
1384 err = 0;
1385
1386 out:
1387 return err;
1388 }
1389
1390 static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
1391 {
1392 unsigned long now = jiffies;
1393 unsigned long next_credit =
1394 vif->credit_timeout.expires +
1395 msecs_to_jiffies(vif->credit_usec / 1000);
1396
1397 /* Timer could already be pending in rare cases. */
1398 if (timer_pending(&vif->credit_timeout))
1399 return true;
1400
1401 /* Passed the point where we can replenish credit? */
1402 if (time_after_eq(now, next_credit)) {
1403 vif->credit_timeout.expires = now;
1404 tx_add_credit(vif);
1405 }
1406
1407 /* Still too big to send right now? Set a callback. */
1408 if (size > vif->remaining_credit) {
1409 vif->credit_timeout.data =
1410 (unsigned long)vif;
1411 vif->credit_timeout.function =
1412 tx_credit_callback;
1413 mod_timer(&vif->credit_timeout,
1414 next_credit);
1415
1416 return true;
1417 }
1418
1419 return false;
1420 }
1421
1422 static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk)
1423 {
1424 struct gnttab_copy *gop = netbk->tx_copy_ops, *request_gop;
1425 struct sk_buff *skb;
1426 int ret;
1427
1428 while ((nr_pending_reqs(netbk) + XEN_NETBK_LEGACY_SLOTS_MAX
1429 < MAX_PENDING_REQS) &&
1430 !list_empty(&netbk->net_schedule_list)) {
1431 struct xenvif *vif;
1432 struct xen_netif_tx_request txreq;
1433 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
1434 struct page *page;
1435 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
1436 u16 pending_idx;
1437 RING_IDX idx;
1438 int work_to_do;
1439 unsigned int data_len;
1440 pending_ring_idx_t index;
1441
1442 /* Get a netif from the list with work to do. */
1443 vif = poll_net_schedule_list(netbk);
1444 /* This can sometimes happen because the test of
1445 * list_empty(net_schedule_list) at the top of the
1446 * loop is unlocked. Just go back and have another
1447 * look.
1448 */
1449 if (!vif)
1450 continue;
1451
1452 if (vif->tx.sring->req_prod - vif->tx.req_cons >
1453 XEN_NETIF_TX_RING_SIZE) {
1454 netdev_err(vif->dev,
1455 "Impossible number of requests. "
1456 "req_prod %d, req_cons %d, size %ld\n",
1457 vif->tx.sring->req_prod, vif->tx.req_cons,
1458 XEN_NETIF_TX_RING_SIZE);
1459 netbk_fatal_tx_err(vif);
1460 continue;
1461 }
1462
1463 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, work_to_do);
1464 if (!work_to_do) {
1465 xenvif_put(vif);
1466 continue;
1467 }
1468
1469 idx = vif->tx.req_cons;
1470 rmb(); /* Ensure that we see the request before we copy it. */
1471 memcpy(&txreq, RING_GET_REQUEST(&vif->tx, idx), sizeof(txreq));
1472
1473 /* Credit-based scheduling. */
1474 if (txreq.size > vif->remaining_credit &&
1475 tx_credit_exceeded(vif, txreq.size)) {
1476 xenvif_put(vif);
1477 continue;
1478 }
1479
1480 vif->remaining_credit -= txreq.size;
1481
1482 work_to_do--;
1483 vif->tx.req_cons = ++idx;
1484
1485 memset(extras, 0, sizeof(extras));
1486 if (txreq.flags & XEN_NETTXF_extra_info) {
1487 work_to_do = xen_netbk_get_extras(vif, extras,
1488 work_to_do);
1489 idx = vif->tx.req_cons;
1490 if (unlikely(work_to_do < 0))
1491 continue;
1492 }
1493
1494 ret = netbk_count_requests(vif, &txreq, txfrags, work_to_do);
1495 if (unlikely(ret < 0))
1496 continue;
1497
1498 idx += ret;
1499
1500 if (unlikely(txreq.size < ETH_HLEN)) {
1501 netdev_dbg(vif->dev,
1502 "Bad packet size: %d\n", txreq.size);
1503 netbk_tx_err(vif, &txreq, idx);
1504 continue;
1505 }
1506
1507 /* No crossing a page as the payload mustn't fragment. */
1508 if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
1509 netdev_err(vif->dev,
1510 "txreq.offset: %x, size: %u, end: %lu\n",
1511 txreq.offset, txreq.size,
1512 (txreq.offset&~PAGE_MASK) + txreq.size);
1513 netbk_fatal_tx_err(vif);
1514 continue;
1515 }
1516
1517 index = pending_index(netbk->pending_cons);
1518 pending_idx = netbk->pending_ring[index];
1519
1520 data_len = (txreq.size > PKT_PROT_LEN &&
1521 ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
1522 PKT_PROT_LEN : txreq.size;
1523
1524 skb = alloc_skb(data_len + NET_SKB_PAD + NET_IP_ALIGN,
1525 GFP_ATOMIC | __GFP_NOWARN);
1526 if (unlikely(skb == NULL)) {
1527 netdev_dbg(vif->dev,
1528 "Can't allocate a skb in start_xmit.\n");
1529 netbk_tx_err(vif, &txreq, idx);
1530 break;
1531 }
1532
1533 /* Packets passed to netif_rx() must have some headroom. */
1534 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
1535
1536 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1537 struct xen_netif_extra_info *gso;
1538 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1539
1540 if (netbk_set_skb_gso(vif, skb, gso)) {
1541 /* Failure in netbk_set_skb_gso is fatal. */
1542 kfree_skb(skb);
1543 continue;
1544 }
1545 }
1546
1547 /* XXX could copy straight to head */
1548 page = xen_netbk_alloc_page(netbk, pending_idx);
1549 if (!page) {
1550 kfree_skb(skb);
1551 netbk_tx_err(vif, &txreq, idx);
1552 continue;
1553 }
1554
1555 gop->source.u.ref = txreq.gref;
1556 gop->source.domid = vif->domid;
1557 gop->source.offset = txreq.offset;
1558
1559 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
1560 gop->dest.domid = DOMID_SELF;
1561 gop->dest.offset = txreq.offset;
1562
1563 gop->len = txreq.size;
1564 gop->flags = GNTCOPY_source_gref;
1565
1566 gop++;
1567
1568 memcpy(&netbk->pending_tx_info[pending_idx].req,
1569 &txreq, sizeof(txreq));
1570 netbk->pending_tx_info[pending_idx].vif = vif;
1571 netbk->pending_tx_info[pending_idx].head = index;
1572 *((u16 *)skb->data) = pending_idx;
1573
1574 __skb_put(skb, data_len);
1575
1576 skb_shinfo(skb)->nr_frags = ret;
1577 if (data_len < txreq.size) {
1578 skb_shinfo(skb)->nr_frags++;
1579 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1580 pending_idx);
1581 } else {
1582 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1583 INVALID_PENDING_IDX);
1584 }
1585
1586 netbk->pending_cons++;
1587
1588 request_gop = xen_netbk_get_requests(netbk, vif,
1589 skb, txfrags, gop);
1590 if (request_gop == NULL) {
1591 kfree_skb(skb);
1592 netbk_tx_err(vif, &txreq, idx);
1593 continue;
1594 }
1595 gop = request_gop;
1596
1597 __skb_queue_tail(&netbk->tx_queue, skb);
1598
1599 vif->tx.req_cons = idx;
1600 xen_netbk_check_rx_xenvif(vif);
1601
1602 if ((gop-netbk->tx_copy_ops) >= ARRAY_SIZE(netbk->tx_copy_ops))
1603 break;
1604 }
1605
1606 return gop - netbk->tx_copy_ops;
1607 }
1608
1609 static void xen_netbk_tx_submit(struct xen_netbk *netbk)
1610 {
1611 struct gnttab_copy *gop = netbk->tx_copy_ops;
1612 struct sk_buff *skb;
1613
1614 while ((skb = __skb_dequeue(&netbk->tx_queue)) != NULL) {
1615 struct xen_netif_tx_request *txp;
1616 struct xenvif *vif;
1617 u16 pending_idx;
1618 unsigned data_len;
1619
1620 pending_idx = *((u16 *)skb->data);
1621 vif = netbk->pending_tx_info[pending_idx].vif;
1622 txp = &netbk->pending_tx_info[pending_idx].req;
1623
1624 /* Check the remap error code. */
1625 if (unlikely(xen_netbk_tx_check_gop(netbk, skb, &gop))) {
1626 netdev_dbg(vif->dev, "netback grant failed.\n");
1627 skb_shinfo(skb)->nr_frags = 0;
1628 kfree_skb(skb);
1629 continue;
1630 }
1631
1632 data_len = skb->len;
1633 memcpy(skb->data,
1634 (void *)(idx_to_kaddr(netbk, pending_idx)|txp->offset),
1635 data_len);
1636 if (data_len < txp->size) {
1637 /* Append the packet payload as a fragment. */
1638 txp->offset += data_len;
1639 txp->size -= data_len;
1640 } else {
1641 /* Schedule a response immediately. */
1642 xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
1643 }
1644
1645 if (txp->flags & XEN_NETTXF_csum_blank)
1646 skb->ip_summed = CHECKSUM_PARTIAL;
1647 else if (txp->flags & XEN_NETTXF_data_validated)
1648 skb->ip_summed = CHECKSUM_UNNECESSARY;
1649
1650 xen_netbk_fill_frags(netbk, skb);
1651
1652 /*
1653 * If the initial fragment was < PKT_PROT_LEN then
1654 * pull through some bytes from the other fragments to
1655 * increase the linear region to PKT_PROT_LEN bytes.
1656 */
1657 if (skb_headlen(skb) < PKT_PROT_LEN && skb_is_nonlinear(skb)) {
1658 int target = min_t(int, skb->len, PKT_PROT_LEN);
1659 __pskb_pull_tail(skb, target - skb_headlen(skb));
1660 }
1661
1662 skb->dev = vif->dev;
1663 skb->protocol = eth_type_trans(skb, skb->dev);
1664 skb_reset_network_header(skb);
1665
1666 if (checksum_setup(vif, skb)) {
1667 netdev_dbg(vif->dev,
1668 "Can't setup checksum in net_tx_action\n");
1669 kfree_skb(skb);
1670 continue;
1671 }
1672
1673 skb_probe_transport_header(skb, 0);
1674
1675 vif->dev->stats.rx_bytes += skb->len;
1676 vif->dev->stats.rx_packets++;
1677
1678 xenvif_receive_skb(vif, skb);
1679 }
1680 }
1681
1682 /* Called after netfront has transmitted */
1683 static void xen_netbk_tx_action(struct xen_netbk *netbk)
1684 {
1685 unsigned nr_gops;
1686
1687 nr_gops = xen_netbk_tx_build_gops(netbk);
1688
1689 if (nr_gops == 0)
1690 return;
1691
1692 gnttab_batch_copy(netbk->tx_copy_ops, nr_gops);
1693
1694 xen_netbk_tx_submit(netbk);
1695 }
1696
1697 static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx,
1698 u8 status)
1699 {
1700 struct xenvif *vif;
1701 struct pending_tx_info *pending_tx_info;
1702 pending_ring_idx_t head;
1703 u16 peek; /* peek into next tx request */
1704
1705 BUG_ON(netbk->mmap_pages[pending_idx] == (void *)(~0UL));
1706
1707 /* Already complete? */
1708 if (netbk->mmap_pages[pending_idx] == NULL)
1709 return;
1710
1711 pending_tx_info = &netbk->pending_tx_info[pending_idx];
1712
1713 vif = pending_tx_info->vif;
1714 head = pending_tx_info->head;
1715
1716 BUG_ON(!pending_tx_is_head(netbk, head));
1717 BUG_ON(netbk->pending_ring[pending_index(head)] != pending_idx);
1718
1719 do {
1720 pending_ring_idx_t index;
1721 pending_ring_idx_t idx = pending_index(head);
1722 u16 info_idx = netbk->pending_ring[idx];
1723
1724 pending_tx_info = &netbk->pending_tx_info[info_idx];
1725 make_tx_response(vif, &pending_tx_info->req, status);
1726
1727 /* Setting any number other than
1728 * INVALID_PENDING_RING_IDX indicates this slot is
1729 * starting a new packet / ending a previous packet.
1730 */
1731 pending_tx_info->head = 0;
1732
1733 index = pending_index(netbk->pending_prod++);
1734 netbk->pending_ring[index] = netbk->pending_ring[info_idx];
1735
1736 xenvif_put(vif);
1737
1738 peek = netbk->pending_ring[pending_index(++head)];
1739
1740 } while (!pending_tx_is_head(netbk, peek));
1741
1742 netbk->mmap_pages[pending_idx]->mapping = 0;
1743 put_page(netbk->mmap_pages[pending_idx]);
1744 netbk->mmap_pages[pending_idx] = NULL;
1745 }
1746
1747
1748 static void make_tx_response(struct xenvif *vif,
1749 struct xen_netif_tx_request *txp,
1750 s8 st)
1751 {
1752 RING_IDX i = vif->tx.rsp_prod_pvt;
1753 struct xen_netif_tx_response *resp;
1754 int notify;
1755
1756 resp = RING_GET_RESPONSE(&vif->tx, i);
1757 resp->id = txp->id;
1758 resp->status = st;
1759
1760 if (txp->flags & XEN_NETTXF_extra_info)
1761 RING_GET_RESPONSE(&vif->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1762
1763 vif->tx.rsp_prod_pvt = ++i;
1764 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->tx, notify);
1765 if (notify)
1766 notify_remote_via_irq(vif->irq);
1767 }
1768
1769 static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
1770 u16 id,
1771 s8 st,
1772 u16 offset,
1773 u16 size,
1774 u16 flags)
1775 {
1776 RING_IDX i = vif->rx.rsp_prod_pvt;
1777 struct xen_netif_rx_response *resp;
1778
1779 resp = RING_GET_RESPONSE(&vif->rx, i);
1780 resp->offset = offset;
1781 resp->flags = flags;
1782 resp->id = id;
1783 resp->status = (s16)size;
1784 if (st < 0)
1785 resp->status = (s16)st;
1786
1787 vif->rx.rsp_prod_pvt = ++i;
1788
1789 return resp;
1790 }
1791
1792 static inline int rx_work_todo(struct xen_netbk *netbk)
1793 {
1794 return !skb_queue_empty(&netbk->rx_queue);
1795 }
1796
1797 static inline int tx_work_todo(struct xen_netbk *netbk)
1798 {
1799
1800 if ((nr_pending_reqs(netbk) + XEN_NETBK_LEGACY_SLOTS_MAX
1801 < MAX_PENDING_REQS) &&
1802 !list_empty(&netbk->net_schedule_list))
1803 return 1;
1804
1805 return 0;
1806 }
1807
1808 static int xen_netbk_kthread(void *data)
1809 {
1810 struct xen_netbk *netbk = data;
1811 while (!kthread_should_stop()) {
1812 wait_event_interruptible(netbk->wq,
1813 rx_work_todo(netbk) ||
1814 tx_work_todo(netbk) ||
1815 kthread_should_stop());
1816 cond_resched();
1817
1818 if (kthread_should_stop())
1819 break;
1820
1821 if (rx_work_todo(netbk))
1822 xen_netbk_rx_action(netbk);
1823
1824 if (tx_work_todo(netbk))
1825 xen_netbk_tx_action(netbk);
1826 }
1827
1828 return 0;
1829 }
1830
1831 void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
1832 {
1833 if (vif->tx.sring)
1834 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1835 vif->tx.sring);
1836 if (vif->rx.sring)
1837 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1838 vif->rx.sring);
1839 }
1840
1841 int xen_netbk_map_frontend_rings(struct xenvif *vif,
1842 grant_ref_t tx_ring_ref,
1843 grant_ref_t rx_ring_ref)
1844 {
1845 void *addr;
1846 struct xen_netif_tx_sring *txs;
1847 struct xen_netif_rx_sring *rxs;
1848
1849 int err = -ENOMEM;
1850
1851 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1852 tx_ring_ref, &addr);
1853 if (err)
1854 goto err;
1855
1856 txs = (struct xen_netif_tx_sring *)addr;
1857 BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
1858
1859 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1860 rx_ring_ref, &addr);
1861 if (err)
1862 goto err;
1863
1864 rxs = (struct xen_netif_rx_sring *)addr;
1865 BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
1866
1867 vif->rx_req_cons_peek = 0;
1868
1869 return 0;
1870
1871 err:
1872 xen_netbk_unmap_frontend_rings(vif);
1873 return err;
1874 }
1875
1876 static int __init netback_init(void)
1877 {
1878 int i;
1879 int rc = 0;
1880 int group;
1881
1882 if (!xen_domain())
1883 return -ENODEV;
1884
1885 if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
1886 printk(KERN_INFO
1887 "xen-netback: fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
1888 fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
1889 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
1890 }
1891
1892 xen_netbk_group_nr = num_online_cpus();
1893 xen_netbk = vzalloc(sizeof(struct xen_netbk) * xen_netbk_group_nr);
1894 if (!xen_netbk)
1895 return -ENOMEM;
1896
1897 for (group = 0; group < xen_netbk_group_nr; group++) {
1898 struct xen_netbk *netbk = &xen_netbk[group];
1899 skb_queue_head_init(&netbk->rx_queue);
1900 skb_queue_head_init(&netbk->tx_queue);
1901
1902 init_timer(&netbk->net_timer);
1903 netbk->net_timer.data = (unsigned long)netbk;
1904 netbk->net_timer.function = xen_netbk_alarm;
1905
1906 netbk->pending_cons = 0;
1907 netbk->pending_prod = MAX_PENDING_REQS;
1908 for (i = 0; i < MAX_PENDING_REQS; i++)
1909 netbk->pending_ring[i] = i;
1910
1911 init_waitqueue_head(&netbk->wq);
1912 netbk->task = kthread_create(xen_netbk_kthread,
1913 (void *)netbk,
1914 "netback/%u", group);
1915
1916 if (IS_ERR(netbk->task)) {
1917 printk(KERN_ALERT "kthread_create() fails at netback\n");
1918 del_timer(&netbk->net_timer);
1919 rc = PTR_ERR(netbk->task);
1920 goto failed_init;
1921 }
1922
1923 kthread_bind(netbk->task, group);
1924
1925 INIT_LIST_HEAD(&netbk->net_schedule_list);
1926
1927 spin_lock_init(&netbk->net_schedule_list_lock);
1928
1929 atomic_set(&netbk->netfront_count, 0);
1930
1931 wake_up_process(netbk->task);
1932 }
1933
1934 rc = xenvif_xenbus_init();
1935 if (rc)
1936 goto failed_init;
1937
1938 return 0;
1939
1940 failed_init:
1941 while (--group >= 0) {
1942 struct xen_netbk *netbk = &xen_netbk[group];
1943 for (i = 0; i < MAX_PENDING_REQS; i++) {
1944 if (netbk->mmap_pages[i])
1945 __free_page(netbk->mmap_pages[i]);
1946 }
1947 del_timer(&netbk->net_timer);
1948 kthread_stop(netbk->task);
1949 }
1950 vfree(xen_netbk);
1951 return rc;
1952
1953 }
1954
1955 module_init(netback_init);
1956
1957 MODULE_LICENSE("Dual BSD/GPL");
1958 MODULE_ALIAS("xen-backend:vif");
Linux kernel - Deliverables
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