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at86rf230: mask irq's before deregister device
[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 /* This is a miniumum size for the linear area to avoid lots of
113 * calls to __pskb_pull_tail() as we set up checksum offsets. The
114 * value 128 was chosen as it covers all IPv4 and most likely
115 * IPv6 headers.
116 */
117 #define PKT_PROT_LEN 128
118
119 static u16 frag_get_pending_idx(skb_frag_t *frag)
120 {
121 return (u16)frag->page_offset;
122 }
123
124 static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
125 {
126 frag->page_offset = pending_idx;
127 }
128
129 static inline pending_ring_idx_t pending_index(unsigned i)
130 {
131 return i & (MAX_PENDING_REQS-1);
132 }
133
134 static inline pending_ring_idx_t nr_pending_reqs(struct xenvif *vif)
135 {
136 return MAX_PENDING_REQS -
137 vif->pending_prod + vif->pending_cons;
138 }
139
140 bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed)
141 {
142 RING_IDX prod, cons;
143
144 do {
145 prod = vif->rx.sring->req_prod;
146 cons = vif->rx.req_cons;
147
148 if (prod - cons >= needed)
149 return true;
150
151 vif->rx.sring->req_event = prod + 1;
152
153 /* Make sure event is visible before we check prod
154 * again.
155 */
156 mb();
157 } while (vif->rx.sring->req_prod != prod);
158
159 return false;
160 }
161
162 /*
163 * Returns true if we should start a new receive buffer instead of
164 * adding 'size' bytes to a buffer which currently contains 'offset'
165 * bytes.
166 */
167 static bool start_new_rx_buffer(int offset, unsigned long size, int head)
168 {
169 /* simple case: we have completely filled the current buffer. */
170 if (offset == MAX_BUFFER_OFFSET)
171 return true;
172
173 /*
174 * complex case: start a fresh buffer if the current frag
175 * would overflow the current buffer but only if:
176 * (i) this frag would fit completely in the next buffer
177 * and (ii) there is already some data in the current buffer
178 * and (iii) this is not the head buffer.
179 *
180 * Where:
181 * - (i) stops us splitting a frag into two copies
182 * unless the frag is too large for a single buffer.
183 * - (ii) stops us from leaving a buffer pointlessly empty.
184 * - (iii) stops us leaving the first buffer
185 * empty. Strictly speaking this is already covered
186 * by (ii) but is explicitly checked because
187 * netfront relies on the first buffer being
188 * non-empty and can crash otherwise.
189 *
190 * This means we will effectively linearise small
191 * frags but do not needlessly split large buffers
192 * into multiple copies tend to give large frags their
193 * own buffers as before.
194 */
195 BUG_ON(size > MAX_BUFFER_OFFSET);
196 if ((offset + size > MAX_BUFFER_OFFSET) && offset && !head)
197 return true;
198
199 return false;
200 }
201
202 struct netrx_pending_operations {
203 unsigned copy_prod, copy_cons;
204 unsigned meta_prod, meta_cons;
205 struct gnttab_copy *copy;
206 struct xenvif_rx_meta *meta;
207 int copy_off;
208 grant_ref_t copy_gref;
209 };
210
211 static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif *vif,
212 struct netrx_pending_operations *npo)
213 {
214 struct xenvif_rx_meta *meta;
215 struct xen_netif_rx_request *req;
216
217 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
218
219 meta = npo->meta + npo->meta_prod++;
220 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
221 meta->gso_size = 0;
222 meta->size = 0;
223 meta->id = req->id;
224
225 npo->copy_off = 0;
226 npo->copy_gref = req->gref;
227
228 return meta;
229 }
230
231 /*
232 * Set up the grant operations for this fragment. If it's a flipping
233 * interface, we also set up the unmap request from here.
234 */
235 static void xenvif_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb,
236 struct netrx_pending_operations *npo,
237 struct page *page, unsigned long size,
238 unsigned long offset, int *head)
239 {
240 struct gnttab_copy *copy_gop;
241 struct xenvif_rx_meta *meta;
242 unsigned long bytes;
243 int gso_type = XEN_NETIF_GSO_TYPE_NONE;
244
245 /* Data must not cross a page boundary. */
246 BUG_ON(size + offset > PAGE_SIZE<<compound_order(page));
247
248 meta = npo->meta + npo->meta_prod - 1;
249
250 /* Skip unused frames from start of page */
251 page += offset >> PAGE_SHIFT;
252 offset &= ~PAGE_MASK;
253
254 while (size > 0) {
255 BUG_ON(offset >= PAGE_SIZE);
256 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
257
258 bytes = PAGE_SIZE - offset;
259
260 if (bytes > size)
261 bytes = size;
262
263 if (start_new_rx_buffer(npo->copy_off, bytes, *head)) {
264 /*
265 * Netfront requires there to be some data in the head
266 * buffer.
267 */
268 BUG_ON(*head);
269
270 meta = get_next_rx_buffer(vif, npo);
271 }
272
273 if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
274 bytes = MAX_BUFFER_OFFSET - npo->copy_off;
275
276 copy_gop = npo->copy + npo->copy_prod++;
277 copy_gop->flags = GNTCOPY_dest_gref;
278 copy_gop->len = bytes;
279
280 copy_gop->source.domid = DOMID_SELF;
281 copy_gop->source.u.gmfn = virt_to_mfn(page_address(page));
282 copy_gop->source.offset = offset;
283
284 copy_gop->dest.domid = vif->domid;
285 copy_gop->dest.offset = npo->copy_off;
286 copy_gop->dest.u.ref = npo->copy_gref;
287
288 npo->copy_off += bytes;
289 meta->size += bytes;
290
291 offset += bytes;
292 size -= bytes;
293
294 /* Next frame */
295 if (offset == PAGE_SIZE && size) {
296 BUG_ON(!PageCompound(page));
297 page++;
298 offset = 0;
299 }
300
301 /* Leave a gap for the GSO descriptor. */
302 if (skb_is_gso(skb)) {
303 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
304 gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
305 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
306 gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
307 }
308
309 if (*head && ((1 << gso_type) & vif->gso_mask))
310 vif->rx.req_cons++;
311
312 *head = 0; /* There must be something in this buffer now. */
313
314 }
315 }
316
317 /*
318 * Prepare an SKB to be transmitted to the frontend.
319 *
320 * This function is responsible for allocating grant operations, meta
321 * structures, etc.
322 *
323 * It returns the number of meta structures consumed. The number of
324 * ring slots used is always equal to the number of meta slots used
325 * plus the number of GSO descriptors used. Currently, we use either
326 * zero GSO descriptors (for non-GSO packets) or one descriptor (for
327 * frontend-side LRO).
328 */
329 static int xenvif_gop_skb(struct sk_buff *skb,
330 struct netrx_pending_operations *npo)
331 {
332 struct xenvif *vif = netdev_priv(skb->dev);
333 int nr_frags = skb_shinfo(skb)->nr_frags;
334 int i;
335 struct xen_netif_rx_request *req;
336 struct xenvif_rx_meta *meta;
337 unsigned char *data;
338 int head = 1;
339 int old_meta_prod;
340 int gso_type;
341
342 old_meta_prod = npo->meta_prod;
343
344 gso_type = XEN_NETIF_GSO_TYPE_NONE;
345 if (skb_is_gso(skb)) {
346 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
347 gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
348 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
349 gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
350 }
351
352 /* Set up a GSO prefix descriptor, if necessary */
353 if ((1 << gso_type) & vif->gso_prefix_mask) {
354 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
355 meta = npo->meta + npo->meta_prod++;
356 meta->gso_type = gso_type;
357 meta->gso_size = skb_shinfo(skb)->gso_size;
358 meta->size = 0;
359 meta->id = req->id;
360 }
361
362 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
363 meta = npo->meta + npo->meta_prod++;
364
365 if ((1 << gso_type) & vif->gso_mask) {
366 meta->gso_type = gso_type;
367 meta->gso_size = skb_shinfo(skb)->gso_size;
368 } else {
369 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
370 meta->gso_size = 0;
371 }
372
373 meta->size = 0;
374 meta->id = req->id;
375 npo->copy_off = 0;
376 npo->copy_gref = req->gref;
377
378 data = skb->data;
379 while (data < skb_tail_pointer(skb)) {
380 unsigned int offset = offset_in_page(data);
381 unsigned int len = PAGE_SIZE - offset;
382
383 if (data + len > skb_tail_pointer(skb))
384 len = skb_tail_pointer(skb) - data;
385
386 xenvif_gop_frag_copy(vif, skb, npo,
387 virt_to_page(data), len, offset, &head);
388 data += len;
389 }
390
391 for (i = 0; i < nr_frags; i++) {
392 xenvif_gop_frag_copy(vif, skb, npo,
393 skb_frag_page(&skb_shinfo(skb)->frags[i]),
394 skb_frag_size(&skb_shinfo(skb)->frags[i]),
395 skb_shinfo(skb)->frags[i].page_offset,
396 &head);
397 }
398
399 return npo->meta_prod - old_meta_prod;
400 }
401
402 /*
403 * This is a twin to xenvif_gop_skb. Assume that xenvif_gop_skb was
404 * used to set up the operations on the top of
405 * netrx_pending_operations, which have since been done. Check that
406 * they didn't give any errors and advance over them.
407 */
408 static int xenvif_check_gop(struct xenvif *vif, int nr_meta_slots,
409 struct netrx_pending_operations *npo)
410 {
411 struct gnttab_copy *copy_op;
412 int status = XEN_NETIF_RSP_OKAY;
413 int i;
414
415 for (i = 0; i < nr_meta_slots; i++) {
416 copy_op = npo->copy + npo->copy_cons++;
417 if (copy_op->status != GNTST_okay) {
418 netdev_dbg(vif->dev,
419 "Bad status %d from copy to DOM%d.\n",
420 copy_op->status, vif->domid);
421 status = XEN_NETIF_RSP_ERROR;
422 }
423 }
424
425 return status;
426 }
427
428 static void xenvif_add_frag_responses(struct xenvif *vif, int status,
429 struct xenvif_rx_meta *meta,
430 int nr_meta_slots)
431 {
432 int i;
433 unsigned long offset;
434
435 /* No fragments used */
436 if (nr_meta_slots <= 1)
437 return;
438
439 nr_meta_slots--;
440
441 for (i = 0; i < nr_meta_slots; i++) {
442 int flags;
443 if (i == nr_meta_slots - 1)
444 flags = 0;
445 else
446 flags = XEN_NETRXF_more_data;
447
448 offset = 0;
449 make_rx_response(vif, meta[i].id, status, offset,
450 meta[i].size, flags);
451 }
452 }
453
454 struct skb_cb_overlay {
455 int meta_slots_used;
456 };
457
458 void xenvif_kick_thread(struct xenvif *vif)
459 {
460 wake_up(&vif->wq);
461 }
462
463 static void xenvif_rx_action(struct xenvif *vif)
464 {
465 s8 status;
466 u16 flags;
467 struct xen_netif_rx_response *resp;
468 struct sk_buff_head rxq;
469 struct sk_buff *skb;
470 LIST_HEAD(notify);
471 int ret;
472 unsigned long offset;
473 struct skb_cb_overlay *sco;
474 bool need_to_notify = false;
475
476 struct netrx_pending_operations npo = {
477 .copy = vif->grant_copy_op,
478 .meta = vif->meta,
479 };
480
481 skb_queue_head_init(&rxq);
482
483 while ((skb = skb_dequeue(&vif->rx_queue)) != NULL) {
484 RING_IDX max_slots_needed;
485 RING_IDX old_req_cons;
486 RING_IDX ring_slots_used;
487 int i;
488
489 /* We need a cheap worse case estimate for the number of
490 * slots we'll use.
491 */
492
493 max_slots_needed = DIV_ROUND_UP(offset_in_page(skb->data) +
494 skb_headlen(skb),
495 PAGE_SIZE);
496 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
497 unsigned int size;
498 unsigned int offset;
499
500 size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
501 offset = skb_shinfo(skb)->frags[i].page_offset;
502
503 /* For a worse-case estimate we need to factor in
504 * the fragment page offset as this will affect the
505 * number of times xenvif_gop_frag_copy() will
506 * call start_new_rx_buffer().
507 */
508 max_slots_needed += DIV_ROUND_UP(offset + size,
509 PAGE_SIZE);
510 }
511
512 /* To avoid the estimate becoming too pessimal for some
513 * frontends that limit posted rx requests, cap the estimate
514 * at MAX_SKB_FRAGS.
515 */
516 if (max_slots_needed > MAX_SKB_FRAGS)
517 max_slots_needed = MAX_SKB_FRAGS;
518
519 /* We may need one more slot for GSO metadata */
520 if (skb_is_gso(skb) &&
521 (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4 ||
522 skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6))
523 max_slots_needed++;
524
525 /* If the skb may not fit then bail out now */
526 if (!xenvif_rx_ring_slots_available(vif, max_slots_needed)) {
527 skb_queue_head(&vif->rx_queue, skb);
528 need_to_notify = true;
529 vif->rx_last_skb_slots = max_slots_needed;
530 break;
531 } else
532 vif->rx_last_skb_slots = 0;
533
534 sco = (struct skb_cb_overlay *)skb->cb;
535
536 old_req_cons = vif->rx.req_cons;
537 sco->meta_slots_used = xenvif_gop_skb(skb, &npo);
538 ring_slots_used = vif->rx.req_cons - old_req_cons;
539
540 BUG_ON(ring_slots_used > max_slots_needed);
541
542 __skb_queue_tail(&rxq, skb);
543 }
544
545 BUG_ON(npo.meta_prod > ARRAY_SIZE(vif->meta));
546
547 if (!npo.copy_prod)
548 goto done;
549
550 BUG_ON(npo.copy_prod > MAX_GRANT_COPY_OPS);
551 gnttab_batch_copy(vif->grant_copy_op, npo.copy_prod);
552
553 while ((skb = __skb_dequeue(&rxq)) != NULL) {
554 sco = (struct skb_cb_overlay *)skb->cb;
555
556 if ((1 << vif->meta[npo.meta_cons].gso_type) &
557 vif->gso_prefix_mask) {
558 resp = RING_GET_RESPONSE(&vif->rx,
559 vif->rx.rsp_prod_pvt++);
560
561 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
562
563 resp->offset = vif->meta[npo.meta_cons].gso_size;
564 resp->id = vif->meta[npo.meta_cons].id;
565 resp->status = sco->meta_slots_used;
566
567 npo.meta_cons++;
568 sco->meta_slots_used--;
569 }
570
571
572 vif->dev->stats.tx_bytes += skb->len;
573 vif->dev->stats.tx_packets++;
574
575 status = xenvif_check_gop(vif, sco->meta_slots_used, &npo);
576
577 if (sco->meta_slots_used == 1)
578 flags = 0;
579 else
580 flags = XEN_NETRXF_more_data;
581
582 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
583 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
584 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
585 /* remote but checksummed. */
586 flags |= XEN_NETRXF_data_validated;
587
588 offset = 0;
589 resp = make_rx_response(vif, vif->meta[npo.meta_cons].id,
590 status, offset,
591 vif->meta[npo.meta_cons].size,
592 flags);
593
594 if ((1 << vif->meta[npo.meta_cons].gso_type) &
595 vif->gso_mask) {
596 struct xen_netif_extra_info *gso =
597 (struct xen_netif_extra_info *)
598 RING_GET_RESPONSE(&vif->rx,
599 vif->rx.rsp_prod_pvt++);
600
601 resp->flags |= XEN_NETRXF_extra_info;
602
603 gso->u.gso.type = vif->meta[npo.meta_cons].gso_type;
604 gso->u.gso.size = vif->meta[npo.meta_cons].gso_size;
605 gso->u.gso.pad = 0;
606 gso->u.gso.features = 0;
607
608 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
609 gso->flags = 0;
610 }
611
612 xenvif_add_frag_responses(vif, status,
613 vif->meta + npo.meta_cons + 1,
614 sco->meta_slots_used);
615
616 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret);
617
618 need_to_notify |= !!ret;
619
620 npo.meta_cons += sco->meta_slots_used;
621 dev_kfree_skb(skb);
622 }
623
624 done:
625 if (need_to_notify)
626 notify_remote_via_irq(vif->rx_irq);
627 }
628
629 void xenvif_check_rx_xenvif(struct xenvif *vif)
630 {
631 int more_to_do;
632
633 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
634
635 if (more_to_do)
636 napi_schedule(&vif->napi);
637 }
638
639 static void tx_add_credit(struct xenvif *vif)
640 {
641 unsigned long max_burst, max_credit;
642
643 /*
644 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
645 * Otherwise the interface can seize up due to insufficient credit.
646 */
647 max_burst = RING_GET_REQUEST(&vif->tx, vif->tx.req_cons)->size;
648 max_burst = min(max_burst, 131072UL);
649 max_burst = max(max_burst, vif->credit_bytes);
650
651 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
652 max_credit = vif->remaining_credit + vif->credit_bytes;
653 if (max_credit < vif->remaining_credit)
654 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
655
656 vif->remaining_credit = min(max_credit, max_burst);
657 }
658
659 static void tx_credit_callback(unsigned long data)
660 {
661 struct xenvif *vif = (struct xenvif *)data;
662 tx_add_credit(vif);
663 xenvif_check_rx_xenvif(vif);
664 }
665
666 static void xenvif_tx_err(struct xenvif *vif,
667 struct xen_netif_tx_request *txp, RING_IDX end)
668 {
669 RING_IDX cons = vif->tx.req_cons;
670
671 do {
672 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
673 if (cons == end)
674 break;
675 txp = RING_GET_REQUEST(&vif->tx, cons++);
676 } while (1);
677 vif->tx.req_cons = cons;
678 }
679
680 static void xenvif_fatal_tx_err(struct xenvif *vif)
681 {
682 netdev_err(vif->dev, "fatal error; disabling device\n");
683 xenvif_carrier_off(vif);
684 }
685
686 static int xenvif_count_requests(struct xenvif *vif,
687 struct xen_netif_tx_request *first,
688 struct xen_netif_tx_request *txp,
689 int work_to_do)
690 {
691 RING_IDX cons = vif->tx.req_cons;
692 int slots = 0;
693 int drop_err = 0;
694 int more_data;
695
696 if (!(first->flags & XEN_NETTXF_more_data))
697 return 0;
698
699 do {
700 struct xen_netif_tx_request dropped_tx = { 0 };
701
702 if (slots >= work_to_do) {
703 netdev_err(vif->dev,
704 "Asked for %d slots but exceeds this limit\n",
705 work_to_do);
706 xenvif_fatal_tx_err(vif);
707 return -ENODATA;
708 }
709
710 /* This guest is really using too many slots and
711 * considered malicious.
712 */
713 if (unlikely(slots >= fatal_skb_slots)) {
714 netdev_err(vif->dev,
715 "Malicious frontend using %d slots, threshold %u\n",
716 slots, fatal_skb_slots);
717 xenvif_fatal_tx_err(vif);
718 return -E2BIG;
719 }
720
721 /* Xen network protocol had implicit dependency on
722 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
723 * the historical MAX_SKB_FRAGS value 18 to honor the
724 * same behavior as before. Any packet using more than
725 * 18 slots but less than fatal_skb_slots slots is
726 * dropped
727 */
728 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
729 if (net_ratelimit())
730 netdev_dbg(vif->dev,
731 "Too many slots (%d) exceeding limit (%d), dropping packet\n",
732 slots, XEN_NETBK_LEGACY_SLOTS_MAX);
733 drop_err = -E2BIG;
734 }
735
736 if (drop_err)
737 txp = &dropped_tx;
738
739 memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + slots),
740 sizeof(*txp));
741
742 /* If the guest submitted a frame >= 64 KiB then
743 * first->size overflowed and following slots will
744 * appear to be larger than the frame.
745 *
746 * This cannot be fatal error as there are buggy
747 * frontends that do this.
748 *
749 * Consume all slots and drop the packet.
750 */
751 if (!drop_err && txp->size > first->size) {
752 if (net_ratelimit())
753 netdev_dbg(vif->dev,
754 "Invalid tx request, slot size %u > remaining size %u\n",
755 txp->size, first->size);
756 drop_err = -EIO;
757 }
758
759 first->size -= txp->size;
760 slots++;
761
762 if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
763 netdev_err(vif->dev, "Cross page boundary, txp->offset: %x, size: %u\n",
764 txp->offset, txp->size);
765 xenvif_fatal_tx_err(vif);
766 return -EINVAL;
767 }
768
769 more_data = txp->flags & XEN_NETTXF_more_data;
770
771 if (!drop_err)
772 txp++;
773
774 } while (more_data);
775
776 if (drop_err) {
777 xenvif_tx_err(vif, first, cons + slots);
778 return drop_err;
779 }
780
781 return slots;
782 }
783
784 static struct page *xenvif_alloc_page(struct xenvif *vif,
785 u16 pending_idx)
786 {
787 struct page *page;
788
789 page = alloc_page(GFP_ATOMIC|__GFP_COLD);
790 if (!page)
791 return NULL;
792 vif->mmap_pages[pending_idx] = page;
793
794 return page;
795 }
796
797 static struct gnttab_copy *xenvif_get_requests(struct xenvif *vif,
798 struct sk_buff *skb,
799 struct xen_netif_tx_request *txp,
800 struct gnttab_copy *gop)
801 {
802 struct skb_shared_info *shinfo = skb_shinfo(skb);
803 skb_frag_t *frags = shinfo->frags;
804 u16 pending_idx = *((u16 *)skb->data);
805 u16 head_idx = 0;
806 int slot, start;
807 struct page *page;
808 pending_ring_idx_t index, start_idx = 0;
809 uint16_t dst_offset;
810 unsigned int nr_slots;
811 struct pending_tx_info *first = NULL;
812
813 /* At this point shinfo->nr_frags is in fact the number of
814 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
815 */
816 nr_slots = shinfo->nr_frags;
817
818 /* Skip first skb fragment if it is on same page as header fragment. */
819 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
820
821 /* Coalesce tx requests, at this point the packet passed in
822 * should be <= 64K. Any packets larger than 64K have been
823 * handled in xenvif_count_requests().
824 */
825 for (shinfo->nr_frags = slot = start; slot < nr_slots;
826 shinfo->nr_frags++) {
827 struct pending_tx_info *pending_tx_info =
828 vif->pending_tx_info;
829
830 page = alloc_page(GFP_ATOMIC|__GFP_COLD);
831 if (!page)
832 goto err;
833
834 dst_offset = 0;
835 first = NULL;
836 while (dst_offset < PAGE_SIZE && slot < nr_slots) {
837 gop->flags = GNTCOPY_source_gref;
838
839 gop->source.u.ref = txp->gref;
840 gop->source.domid = vif->domid;
841 gop->source.offset = txp->offset;
842
843 gop->dest.domid = DOMID_SELF;
844
845 gop->dest.offset = dst_offset;
846 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
847
848 if (dst_offset + txp->size > PAGE_SIZE) {
849 /* This page can only merge a portion
850 * of tx request. Do not increment any
851 * pointer / counter here. The txp
852 * will be dealt with in future
853 * rounds, eventually hitting the
854 * `else` branch.
855 */
856 gop->len = PAGE_SIZE - dst_offset;
857 txp->offset += gop->len;
858 txp->size -= gop->len;
859 dst_offset += gop->len; /* quit loop */
860 } else {
861 /* This tx request can be merged in the page */
862 gop->len = txp->size;
863 dst_offset += gop->len;
864
865 index = pending_index(vif->pending_cons++);
866
867 pending_idx = vif->pending_ring[index];
868
869 memcpy(&pending_tx_info[pending_idx].req, txp,
870 sizeof(*txp));
871
872 /* Poison these fields, corresponding
873 * fields for head tx req will be set
874 * to correct values after the loop.
875 */
876 vif->mmap_pages[pending_idx] = (void *)(~0UL);
877 pending_tx_info[pending_idx].head =
878 INVALID_PENDING_RING_IDX;
879
880 if (!first) {
881 first = &pending_tx_info[pending_idx];
882 start_idx = index;
883 head_idx = pending_idx;
884 }
885
886 txp++;
887 slot++;
888 }
889
890 gop++;
891 }
892
893 first->req.offset = 0;
894 first->req.size = dst_offset;
895 first->head = start_idx;
896 vif->mmap_pages[head_idx] = page;
897 frag_set_pending_idx(&frags[shinfo->nr_frags], head_idx);
898 }
899
900 BUG_ON(shinfo->nr_frags > MAX_SKB_FRAGS);
901
902 return gop;
903 err:
904 /* Unwind, freeing all pages and sending error responses. */
905 while (shinfo->nr_frags-- > start) {
906 xenvif_idx_release(vif,
907 frag_get_pending_idx(&frags[shinfo->nr_frags]),
908 XEN_NETIF_RSP_ERROR);
909 }
910 /* The head too, if necessary. */
911 if (start)
912 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
913
914 return NULL;
915 }
916
917 static int xenvif_tx_check_gop(struct xenvif *vif,
918 struct sk_buff *skb,
919 struct gnttab_copy **gopp)
920 {
921 struct gnttab_copy *gop = *gopp;
922 u16 pending_idx = *((u16 *)skb->data);
923 struct skb_shared_info *shinfo = skb_shinfo(skb);
924 struct pending_tx_info *tx_info;
925 int nr_frags = shinfo->nr_frags;
926 int i, err, start;
927 u16 peek; /* peek into next tx request */
928
929 /* Check status of header. */
930 err = gop->status;
931 if (unlikely(err))
932 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
933
934 /* Skip first skb fragment if it is on same page as header fragment. */
935 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
936
937 for (i = start; i < nr_frags; i++) {
938 int j, newerr;
939 pending_ring_idx_t head;
940
941 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
942 tx_info = &vif->pending_tx_info[pending_idx];
943 head = tx_info->head;
944
945 /* Check error status: if okay then remember grant handle. */
946 do {
947 newerr = (++gop)->status;
948 if (newerr)
949 break;
950 peek = vif->pending_ring[pending_index(++head)];
951 } while (!pending_tx_is_head(vif, peek));
952
953 if (likely(!newerr)) {
954 /* Had a previous error? Invalidate this fragment. */
955 if (unlikely(err))
956 xenvif_idx_release(vif, pending_idx,
957 XEN_NETIF_RSP_OKAY);
958 continue;
959 }
960
961 /* Error on this fragment: respond to client with an error. */
962 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
963
964 /* Not the first error? Preceding frags already invalidated. */
965 if (err)
966 continue;
967
968 /* First error: invalidate header and preceding fragments. */
969 pending_idx = *((u16 *)skb->data);
970 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY);
971 for (j = start; j < i; j++) {
972 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
973 xenvif_idx_release(vif, pending_idx,
974 XEN_NETIF_RSP_OKAY);
975 }
976
977 /* Remember the error: invalidate all subsequent fragments. */
978 err = newerr;
979 }
980
981 *gopp = gop + 1;
982 return err;
983 }
984
985 static void xenvif_fill_frags(struct xenvif *vif, struct sk_buff *skb)
986 {
987 struct skb_shared_info *shinfo = skb_shinfo(skb);
988 int nr_frags = shinfo->nr_frags;
989 int i;
990
991 for (i = 0; i < nr_frags; i++) {
992 skb_frag_t *frag = shinfo->frags + i;
993 struct xen_netif_tx_request *txp;
994 struct page *page;
995 u16 pending_idx;
996
997 pending_idx = frag_get_pending_idx(frag);
998
999 txp = &vif->pending_tx_info[pending_idx].req;
1000 page = virt_to_page(idx_to_kaddr(vif, pending_idx));
1001 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
1002 skb->len += txp->size;
1003 skb->data_len += txp->size;
1004 skb->truesize += txp->size;
1005
1006 /* Take an extra reference to offset xenvif_idx_release */
1007 get_page(vif->mmap_pages[pending_idx]);
1008 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY);
1009 }
1010 }
1011
1012 static int xenvif_get_extras(struct xenvif *vif,
1013 struct xen_netif_extra_info *extras,
1014 int work_to_do)
1015 {
1016 struct xen_netif_extra_info extra;
1017 RING_IDX cons = vif->tx.req_cons;
1018
1019 do {
1020 if (unlikely(work_to_do-- <= 0)) {
1021 netdev_err(vif->dev, "Missing extra info\n");
1022 xenvif_fatal_tx_err(vif);
1023 return -EBADR;
1024 }
1025
1026 memcpy(&extra, RING_GET_REQUEST(&vif->tx, cons),
1027 sizeof(extra));
1028 if (unlikely(!extra.type ||
1029 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1030 vif->tx.req_cons = ++cons;
1031 netdev_err(vif->dev,
1032 "Invalid extra type: %d\n", extra.type);
1033 xenvif_fatal_tx_err(vif);
1034 return -EINVAL;
1035 }
1036
1037 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1038 vif->tx.req_cons = ++cons;
1039 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1040
1041 return work_to_do;
1042 }
1043
1044 static int xenvif_set_skb_gso(struct xenvif *vif,
1045 struct sk_buff *skb,
1046 struct xen_netif_extra_info *gso)
1047 {
1048 if (!gso->u.gso.size) {
1049 netdev_err(vif->dev, "GSO size must not be zero.\n");
1050 xenvif_fatal_tx_err(vif);
1051 return -EINVAL;
1052 }
1053
1054 switch (gso->u.gso.type) {
1055 case XEN_NETIF_GSO_TYPE_TCPV4:
1056 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1057 break;
1058 case XEN_NETIF_GSO_TYPE_TCPV6:
1059 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1060 break;
1061 default:
1062 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1063 xenvif_fatal_tx_err(vif);
1064 return -EINVAL;
1065 }
1066
1067 skb_shinfo(skb)->gso_size = gso->u.gso.size;
1068 /* gso_segs will be calculated later */
1069
1070 return 0;
1071 }
1072
1073 static int checksum_setup(struct xenvif *vif, struct sk_buff *skb)
1074 {
1075 bool recalculate_partial_csum = false;
1076
1077 /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1078 * peers can fail to set NETRXF_csum_blank when sending a GSO
1079 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1080 * recalculate the partial checksum.
1081 */
1082 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1083 vif->rx_gso_checksum_fixup++;
1084 skb->ip_summed = CHECKSUM_PARTIAL;
1085 recalculate_partial_csum = true;
1086 }
1087
1088 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1089 if (skb->ip_summed != CHECKSUM_PARTIAL)
1090 return 0;
1091
1092 return skb_checksum_setup(skb, recalculate_partial_csum);
1093 }
1094
1095 static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
1096 {
1097 u64 now = get_jiffies_64();
1098 u64 next_credit = vif->credit_window_start +
1099 msecs_to_jiffies(vif->credit_usec / 1000);
1100
1101 /* Timer could already be pending in rare cases. */
1102 if (timer_pending(&vif->credit_timeout))
1103 return true;
1104
1105 /* Passed the point where we can replenish credit? */
1106 if (time_after_eq64(now, next_credit)) {
1107 vif->credit_window_start = now;
1108 tx_add_credit(vif);
1109 }
1110
1111 /* Still too big to send right now? Set a callback. */
1112 if (size > vif->remaining_credit) {
1113 vif->credit_timeout.data =
1114 (unsigned long)vif;
1115 vif->credit_timeout.function =
1116 tx_credit_callback;
1117 mod_timer(&vif->credit_timeout,
1118 next_credit);
1119 vif->credit_window_start = next_credit;
1120
1121 return true;
1122 }
1123
1124 return false;
1125 }
1126
1127 static unsigned xenvif_tx_build_gops(struct xenvif *vif, int budget)
1128 {
1129 struct gnttab_copy *gop = vif->tx_copy_ops, *request_gop;
1130 struct sk_buff *skb;
1131 int ret;
1132
1133 while ((nr_pending_reqs(vif) + XEN_NETBK_LEGACY_SLOTS_MAX
1134 < MAX_PENDING_REQS) &&
1135 (skb_queue_len(&vif->tx_queue) < budget)) {
1136 struct xen_netif_tx_request txreq;
1137 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
1138 struct page *page;
1139 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
1140 u16 pending_idx;
1141 RING_IDX idx;
1142 int work_to_do;
1143 unsigned int data_len;
1144 pending_ring_idx_t index;
1145
1146 if (vif->tx.sring->req_prod - vif->tx.req_cons >
1147 XEN_NETIF_TX_RING_SIZE) {
1148 netdev_err(vif->dev,
1149 "Impossible number of requests. "
1150 "req_prod %d, req_cons %d, size %ld\n",
1151 vif->tx.sring->req_prod, vif->tx.req_cons,
1152 XEN_NETIF_TX_RING_SIZE);
1153 xenvif_fatal_tx_err(vif);
1154 continue;
1155 }
1156
1157 work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&vif->tx);
1158 if (!work_to_do)
1159 break;
1160
1161 idx = vif->tx.req_cons;
1162 rmb(); /* Ensure that we see the request before we copy it. */
1163 memcpy(&txreq, RING_GET_REQUEST(&vif->tx, idx), sizeof(txreq));
1164
1165 /* Credit-based scheduling. */
1166 if (txreq.size > vif->remaining_credit &&
1167 tx_credit_exceeded(vif, txreq.size))
1168 break;
1169
1170 vif->remaining_credit -= txreq.size;
1171
1172 work_to_do--;
1173 vif->tx.req_cons = ++idx;
1174
1175 memset(extras, 0, sizeof(extras));
1176 if (txreq.flags & XEN_NETTXF_extra_info) {
1177 work_to_do = xenvif_get_extras(vif, extras,
1178 work_to_do);
1179 idx = vif->tx.req_cons;
1180 if (unlikely(work_to_do < 0))
1181 break;
1182 }
1183
1184 ret = xenvif_count_requests(vif, &txreq, txfrags, work_to_do);
1185 if (unlikely(ret < 0))
1186 break;
1187
1188 idx += ret;
1189
1190 if (unlikely(txreq.size < ETH_HLEN)) {
1191 netdev_dbg(vif->dev,
1192 "Bad packet size: %d\n", txreq.size);
1193 xenvif_tx_err(vif, &txreq, idx);
1194 break;
1195 }
1196
1197 /* No crossing a page as the payload mustn't fragment. */
1198 if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
1199 netdev_err(vif->dev,
1200 "txreq.offset: %x, size: %u, end: %lu\n",
1201 txreq.offset, txreq.size,
1202 (txreq.offset&~PAGE_MASK) + txreq.size);
1203 xenvif_fatal_tx_err(vif);
1204 break;
1205 }
1206
1207 index = pending_index(vif->pending_cons);
1208 pending_idx = vif->pending_ring[index];
1209
1210 data_len = (txreq.size > PKT_PROT_LEN &&
1211 ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
1212 PKT_PROT_LEN : txreq.size;
1213
1214 skb = alloc_skb(data_len + NET_SKB_PAD + NET_IP_ALIGN,
1215 GFP_ATOMIC | __GFP_NOWARN);
1216 if (unlikely(skb == NULL)) {
1217 netdev_dbg(vif->dev,
1218 "Can't allocate a skb in start_xmit.\n");
1219 xenvif_tx_err(vif, &txreq, idx);
1220 break;
1221 }
1222
1223 /* Packets passed to netif_rx() must have some headroom. */
1224 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
1225
1226 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1227 struct xen_netif_extra_info *gso;
1228 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1229
1230 if (xenvif_set_skb_gso(vif, skb, gso)) {
1231 /* Failure in xenvif_set_skb_gso is fatal. */
1232 kfree_skb(skb);
1233 break;
1234 }
1235 }
1236
1237 /* XXX could copy straight to head */
1238 page = xenvif_alloc_page(vif, pending_idx);
1239 if (!page) {
1240 kfree_skb(skb);
1241 xenvif_tx_err(vif, &txreq, idx);
1242 break;
1243 }
1244
1245 gop->source.u.ref = txreq.gref;
1246 gop->source.domid = vif->domid;
1247 gop->source.offset = txreq.offset;
1248
1249 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
1250 gop->dest.domid = DOMID_SELF;
1251 gop->dest.offset = txreq.offset;
1252
1253 gop->len = txreq.size;
1254 gop->flags = GNTCOPY_source_gref;
1255
1256 gop++;
1257
1258 memcpy(&vif->pending_tx_info[pending_idx].req,
1259 &txreq, sizeof(txreq));
1260 vif->pending_tx_info[pending_idx].head = index;
1261 *((u16 *)skb->data) = pending_idx;
1262
1263 __skb_put(skb, data_len);
1264
1265 skb_shinfo(skb)->nr_frags = ret;
1266 if (data_len < txreq.size) {
1267 skb_shinfo(skb)->nr_frags++;
1268 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1269 pending_idx);
1270 } else {
1271 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1272 INVALID_PENDING_IDX);
1273 }
1274
1275 vif->pending_cons++;
1276
1277 request_gop = xenvif_get_requests(vif, skb, txfrags, gop);
1278 if (request_gop == NULL) {
1279 kfree_skb(skb);
1280 xenvif_tx_err(vif, &txreq, idx);
1281 break;
1282 }
1283 gop = request_gop;
1284
1285 __skb_queue_tail(&vif->tx_queue, skb);
1286
1287 vif->tx.req_cons = idx;
1288
1289 if ((gop-vif->tx_copy_ops) >= ARRAY_SIZE(vif->tx_copy_ops))
1290 break;
1291 }
1292
1293 return gop - vif->tx_copy_ops;
1294 }
1295
1296
1297 static int xenvif_tx_submit(struct xenvif *vif)
1298 {
1299 struct gnttab_copy *gop = vif->tx_copy_ops;
1300 struct sk_buff *skb;
1301 int work_done = 0;
1302
1303 while ((skb = __skb_dequeue(&vif->tx_queue)) != NULL) {
1304 struct xen_netif_tx_request *txp;
1305 u16 pending_idx;
1306 unsigned data_len;
1307
1308 pending_idx = *((u16 *)skb->data);
1309 txp = &vif->pending_tx_info[pending_idx].req;
1310
1311 /* Check the remap error code. */
1312 if (unlikely(xenvif_tx_check_gop(vif, skb, &gop))) {
1313 netdev_dbg(vif->dev, "netback grant failed.\n");
1314 skb_shinfo(skb)->nr_frags = 0;
1315 kfree_skb(skb);
1316 continue;
1317 }
1318
1319 data_len = skb->len;
1320 memcpy(skb->data,
1321 (void *)(idx_to_kaddr(vif, pending_idx)|txp->offset),
1322 data_len);
1323 if (data_len < txp->size) {
1324 /* Append the packet payload as a fragment. */
1325 txp->offset += data_len;
1326 txp->size -= data_len;
1327 } else {
1328 /* Schedule a response immediately. */
1329 xenvif_idx_release(vif, pending_idx,
1330 XEN_NETIF_RSP_OKAY);
1331 }
1332
1333 if (txp->flags & XEN_NETTXF_csum_blank)
1334 skb->ip_summed = CHECKSUM_PARTIAL;
1335 else if (txp->flags & XEN_NETTXF_data_validated)
1336 skb->ip_summed = CHECKSUM_UNNECESSARY;
1337
1338 xenvif_fill_frags(vif, skb);
1339
1340 if (skb_is_nonlinear(skb) && skb_headlen(skb) < PKT_PROT_LEN) {
1341 int target = min_t(int, skb->len, PKT_PROT_LEN);
1342 __pskb_pull_tail(skb, target - skb_headlen(skb));
1343 }
1344
1345 skb->dev = vif->dev;
1346 skb->protocol = eth_type_trans(skb, skb->dev);
1347 skb_reset_network_header(skb);
1348
1349 if (checksum_setup(vif, skb)) {
1350 netdev_dbg(vif->dev,
1351 "Can't setup checksum in net_tx_action\n");
1352 kfree_skb(skb);
1353 continue;
1354 }
1355
1356 skb_probe_transport_header(skb, 0);
1357
1358 /* If the packet is GSO then we will have just set up the
1359 * transport header offset in checksum_setup so it's now
1360 * straightforward to calculate gso_segs.
1361 */
1362 if (skb_is_gso(skb)) {
1363 int mss = skb_shinfo(skb)->gso_size;
1364 int hdrlen = skb_transport_header(skb) -
1365 skb_mac_header(skb) +
1366 tcp_hdrlen(skb);
1367
1368 skb_shinfo(skb)->gso_segs =
1369 DIV_ROUND_UP(skb->len - hdrlen, mss);
1370 }
1371
1372 vif->dev->stats.rx_bytes += skb->len;
1373 vif->dev->stats.rx_packets++;
1374
1375 work_done++;
1376
1377 netif_receive_skb(skb);
1378 }
1379
1380 return work_done;
1381 }
1382
1383 /* Called after netfront has transmitted */
1384 int xenvif_tx_action(struct xenvif *vif, int budget)
1385 {
1386 unsigned nr_gops;
1387 int work_done;
1388
1389 if (unlikely(!tx_work_todo(vif)))
1390 return 0;
1391
1392 nr_gops = xenvif_tx_build_gops(vif, budget);
1393
1394 if (nr_gops == 0)
1395 return 0;
1396
1397 gnttab_batch_copy(vif->tx_copy_ops, nr_gops);
1398
1399 work_done = xenvif_tx_submit(vif);
1400
1401 return work_done;
1402 }
1403
1404 static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx,
1405 u8 status)
1406 {
1407 struct pending_tx_info *pending_tx_info;
1408 pending_ring_idx_t head;
1409 u16 peek; /* peek into next tx request */
1410
1411 BUG_ON(vif->mmap_pages[pending_idx] == (void *)(~0UL));
1412
1413 /* Already complete? */
1414 if (vif->mmap_pages[pending_idx] == NULL)
1415 return;
1416
1417 pending_tx_info = &vif->pending_tx_info[pending_idx];
1418
1419 head = pending_tx_info->head;
1420
1421 BUG_ON(!pending_tx_is_head(vif, head));
1422 BUG_ON(vif->pending_ring[pending_index(head)] != pending_idx);
1423
1424 do {
1425 pending_ring_idx_t index;
1426 pending_ring_idx_t idx = pending_index(head);
1427 u16 info_idx = vif->pending_ring[idx];
1428
1429 pending_tx_info = &vif->pending_tx_info[info_idx];
1430 make_tx_response(vif, &pending_tx_info->req, status);
1431
1432 /* Setting any number other than
1433 * INVALID_PENDING_RING_IDX indicates this slot is
1434 * starting a new packet / ending a previous packet.
1435 */
1436 pending_tx_info->head = 0;
1437
1438 index = pending_index(vif->pending_prod++);
1439 vif->pending_ring[index] = vif->pending_ring[info_idx];
1440
1441 peek = vif->pending_ring[pending_index(++head)];
1442
1443 } while (!pending_tx_is_head(vif, peek));
1444
1445 put_page(vif->mmap_pages[pending_idx]);
1446 vif->mmap_pages[pending_idx] = NULL;
1447 }
1448
1449
1450 static void make_tx_response(struct xenvif *vif,
1451 struct xen_netif_tx_request *txp,
1452 s8 st)
1453 {
1454 RING_IDX i = vif->tx.rsp_prod_pvt;
1455 struct xen_netif_tx_response *resp;
1456 int notify;
1457
1458 resp = RING_GET_RESPONSE(&vif->tx, i);
1459 resp->id = txp->id;
1460 resp->status = st;
1461
1462 if (txp->flags & XEN_NETTXF_extra_info)
1463 RING_GET_RESPONSE(&vif->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1464
1465 vif->tx.rsp_prod_pvt = ++i;
1466 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->tx, notify);
1467 if (notify)
1468 notify_remote_via_irq(vif->tx_irq);
1469 }
1470
1471 static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
1472 u16 id,
1473 s8 st,
1474 u16 offset,
1475 u16 size,
1476 u16 flags)
1477 {
1478 RING_IDX i = vif->rx.rsp_prod_pvt;
1479 struct xen_netif_rx_response *resp;
1480
1481 resp = RING_GET_RESPONSE(&vif->rx, i);
1482 resp->offset = offset;
1483 resp->flags = flags;
1484 resp->id = id;
1485 resp->status = (s16)size;
1486 if (st < 0)
1487 resp->status = (s16)st;
1488
1489 vif->rx.rsp_prod_pvt = ++i;
1490
1491 return resp;
1492 }
1493
1494 static inline int rx_work_todo(struct xenvif *vif)
1495 {
1496 return !skb_queue_empty(&vif->rx_queue) &&
1497 xenvif_rx_ring_slots_available(vif, vif->rx_last_skb_slots);
1498 }
1499
1500 static inline int tx_work_todo(struct xenvif *vif)
1501 {
1502
1503 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->tx)) &&
1504 (nr_pending_reqs(vif) + XEN_NETBK_LEGACY_SLOTS_MAX
1505 < MAX_PENDING_REQS))
1506 return 1;
1507
1508 return 0;
1509 }
1510
1511 void xenvif_unmap_frontend_rings(struct xenvif *vif)
1512 {
1513 if (vif->tx.sring)
1514 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1515 vif->tx.sring);
1516 if (vif->rx.sring)
1517 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1518 vif->rx.sring);
1519 }
1520
1521 int xenvif_map_frontend_rings(struct xenvif *vif,
1522 grant_ref_t tx_ring_ref,
1523 grant_ref_t rx_ring_ref)
1524 {
1525 void *addr;
1526 struct xen_netif_tx_sring *txs;
1527 struct xen_netif_rx_sring *rxs;
1528
1529 int err = -ENOMEM;
1530
1531 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1532 tx_ring_ref, &addr);
1533 if (err)
1534 goto err;
1535
1536 txs = (struct xen_netif_tx_sring *)addr;
1537 BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
1538
1539 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1540 rx_ring_ref, &addr);
1541 if (err)
1542 goto err;
1543
1544 rxs = (struct xen_netif_rx_sring *)addr;
1545 BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
1546
1547 return 0;
1548
1549 err:
1550 xenvif_unmap_frontend_rings(vif);
1551 return err;
1552 }
1553
1554 void xenvif_stop_queue(struct xenvif *vif)
1555 {
1556 if (!vif->can_queue)
1557 return;
1558
1559 netif_stop_queue(vif->dev);
1560 }
1561
1562 static void xenvif_start_queue(struct xenvif *vif)
1563 {
1564 if (xenvif_schedulable(vif))
1565 netif_wake_queue(vif->dev);
1566 }
1567
1568 int xenvif_kthread(void *data)
1569 {
1570 struct xenvif *vif = data;
1571 struct sk_buff *skb;
1572
1573 while (!kthread_should_stop()) {
1574 wait_event_interruptible(vif->wq,
1575 rx_work_todo(vif) ||
1576 kthread_should_stop());
1577 if (kthread_should_stop())
1578 break;
1579
1580 if (!skb_queue_empty(&vif->rx_queue))
1581 xenvif_rx_action(vif);
1582
1583 if (skb_queue_empty(&vif->rx_queue) &&
1584 netif_queue_stopped(vif->dev))
1585 xenvif_start_queue(vif);
1586
1587 cond_resched();
1588 }
1589
1590 /* Bin any remaining skbs */
1591 while ((skb = skb_dequeue(&vif->rx_queue)) != NULL)
1592 dev_kfree_skb(skb);
1593
1594 return 0;
1595 }
1596
1597 static int __init netback_init(void)
1598 {
1599 int rc = 0;
1600
1601 if (!xen_domain())
1602 return -ENODEV;
1603
1604 if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
1605 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
1606 fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
1607 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
1608 }
1609
1610 rc = xenvif_xenbus_init();
1611 if (rc)
1612 goto failed_init;
1613
1614 return 0;
1615
1616 failed_init:
1617 return rc;
1618 }
1619
1620 module_init(netback_init);
1621
1622 static void __exit netback_fini(void)
1623 {
1624 xenvif_xenbus_fini();
1625 }
1626 module_exit(netback_fini);
1627
1628 MODULE_LICENSE("Dual BSD/GPL");
1629 MODULE_ALIAS("xen-backend:vif");
Linux kernel - Deliverables
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