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1/*
2 * Back-end of the driver for virtual network devices. This portion of the
3 * driver exports a 'unified' network-device interface that can be accessed
4 * by any operating system that implements a compatible front end. A
5 * reference front-end implementation can be found in:
6 * drivers/net/xen-netfront.c
7 *
8 * Copyright (c) 2002-2005, K A Fraser
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License version 2
12 * as published by the Free Software Foundation; or, when distributed
13 * separately from the Linux kernel or incorporated into other
14 * software packages, subject to the following license:
15 *
16 * Permission is hereby granted, free of charge, to any person obtaining a copy
17 * of this source file (the "Software"), to deal in the Software without
18 * restriction, including without limitation the rights to use, copy, modify,
19 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
20 * and to permit persons to whom the Software is furnished to do so, subject to
21 * the following conditions:
22 *
23 * The above copyright notice and this permission notice shall be included in
24 * all copies or substantial portions of the Software.
25 *
26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
28 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
29 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
30 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
31 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
32 * IN THE SOFTWARE.
33 */
34
35#include "common.h"
36
37#include <linux/kthread.h>
38#include <linux/if_vlan.h>
39#include <linux/udp.h>
40#include <linux/highmem.h>
41
42#include <net/tcp.h>
43
44#include <xen/xen.h>
45#include <xen/events.h>
46#include <xen/interface/memory.h>
47#include <xen/page.h>
48
49#include <asm/xen/hypercall.h>
50
51/* Provide an option to disable split event channels at load time as
52 * event channels are limited resource. Split event channels are
53 * enabled by default.
54 */
55bool separate_tx_rx_irq = true;
56module_param(separate_tx_rx_irq, bool, 0644);
57
58/* The time that packets can stay on the guest Rx internal queue
59 * before they are dropped.
60 */
61unsigned int rx_drain_timeout_msecs = 10000;
62module_param(rx_drain_timeout_msecs, uint, 0444);
63
64/* The length of time before the frontend is considered unresponsive
65 * because it isn't providing Rx slots.
66 */
67unsigned int rx_stall_timeout_msecs = 60000;
68module_param(rx_stall_timeout_msecs, uint, 0444);
69
70#define MAX_QUEUES_DEFAULT 8
71unsigned int xenvif_max_queues;
72module_param_named(max_queues, xenvif_max_queues, uint, 0644);
73MODULE_PARM_DESC(max_queues,
74 "Maximum number of queues per virtual interface");
75
76/*
77 * This is the maximum slots a skb can have. If a guest sends a skb
78 * which exceeds this limit it is considered malicious.
79 */
80#define FATAL_SKB_SLOTS_DEFAULT 20
81static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
82module_param(fatal_skb_slots, uint, 0444);
83
84/* The amount to copy out of the first guest Tx slot into the skb's
85 * linear area. If the first slot has more data, it will be mapped
86 * and put into the first frag.
87 *
88 * This is sized to avoid pulling headers from the frags for most
89 * TCP/IP packets.
90 */
91#define XEN_NETBACK_TX_COPY_LEN 128
92
93/* This is the maximum number of flows in the hash cache. */
94#define XENVIF_HASH_CACHE_SIZE_DEFAULT 64
95unsigned int xenvif_hash_cache_size = XENVIF_HASH_CACHE_SIZE_DEFAULT;
96module_param_named(hash_cache_size, xenvif_hash_cache_size, uint, 0644);
97MODULE_PARM_DESC(hash_cache_size, "Number of flows in the hash cache");
98
99/* The module parameter tells that we have to put data
100 * for xen-netfront with the XDP_PACKET_HEADROOM offset
101 * needed for XDP processing
102 */
103bool provides_xdp_headroom = true;
104module_param(provides_xdp_headroom, bool, 0644);
105
106static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
107 s8 status);
108
109static void make_tx_response(struct xenvif_queue *queue,
110 const struct xen_netif_tx_request *txp,
111 unsigned int extra_count,
112 s8 status);
113
114static void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx);
115
116static inline int tx_work_todo(struct xenvif_queue *queue);
117
118static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
119 u16 idx)
120{
121 return page_to_pfn(queue->mmap_pages[idx]);
122}
123
124static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
125 u16 idx)
126{
127 return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
128}
129
130#define callback_param(vif, pending_idx) \
131 (vif->pending_tx_info[pending_idx].callback_struct)
132
133/* Find the containing VIF's structure from a pointer in pending_tx_info array
134 */
135static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info_msgzc *ubuf)
136{
137 u16 pending_idx = ubuf->desc;
138 struct pending_tx_info *temp =
139 container_of(ubuf, struct pending_tx_info, callback_struct);
140 return container_of(temp - pending_idx,
141 struct xenvif_queue,
142 pending_tx_info[0]);
143}
144
145static u16 frag_get_pending_idx(skb_frag_t *frag)
146{
147 return (u16)skb_frag_off(frag);
148}
149
150static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
151{
152 skb_frag_off_set(frag, pending_idx);
153}
154
155static inline pending_ring_idx_t pending_index(unsigned i)
156{
157 return i & (MAX_PENDING_REQS-1);
158}
159
160void xenvif_kick_thread(struct xenvif_queue *queue)
161{
162 wake_up(&queue->wq);
163}
164
165void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
166{
167 int more_to_do;
168
169 RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
170
171 if (more_to_do)
172 napi_schedule(&queue->napi);
173 else if (atomic_fetch_andnot(NETBK_TX_EOI | NETBK_COMMON_EOI,
174 &queue->eoi_pending) &
175 (NETBK_TX_EOI | NETBK_COMMON_EOI))
176 xen_irq_lateeoi(queue->tx_irq, 0);
177}
178
179static void tx_add_credit(struct xenvif_queue *queue)
180{
181 unsigned long max_burst, max_credit;
182
183 /*
184 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
185 * Otherwise the interface can seize up due to insufficient credit.
186 */
187 max_burst = max(131072UL, queue->credit_bytes);
188
189 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
190 max_credit = queue->remaining_credit + queue->credit_bytes;
191 if (max_credit < queue->remaining_credit)
192 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
193
194 queue->remaining_credit = min(max_credit, max_burst);
195 queue->rate_limited = false;
196}
197
198void xenvif_tx_credit_callback(struct timer_list *t)
199{
200 struct xenvif_queue *queue = from_timer(queue, t, credit_timeout);
201 tx_add_credit(queue);
202 xenvif_napi_schedule_or_enable_events(queue);
203}
204
205static void xenvif_tx_err(struct xenvif_queue *queue,
206 struct xen_netif_tx_request *txp,
207 unsigned int extra_count, RING_IDX end)
208{
209 RING_IDX cons = queue->tx.req_cons;
210
211 do {
212 make_tx_response(queue, txp, extra_count, XEN_NETIF_RSP_ERROR);
213 if (cons == end)
214 break;
215 RING_COPY_REQUEST(&queue->tx, cons++, txp);
216 extra_count = 0; /* only the first frag can have extras */
217 } while (1);
218 queue->tx.req_cons = cons;
219}
220
221static void xenvif_fatal_tx_err(struct xenvif *vif)
222{
223 netdev_err(vif->dev, "fatal error; disabling device\n");
224 vif->disabled = true;
225 /* Disable the vif from queue 0's kthread */
226 if (vif->num_queues)
227 xenvif_kick_thread(&vif->queues[0]);
228}
229
230static int xenvif_count_requests(struct xenvif_queue *queue,
231 struct xen_netif_tx_request *first,
232 unsigned int extra_count,
233 struct xen_netif_tx_request *txp,
234 int work_to_do)
235{
236 RING_IDX cons = queue->tx.req_cons;
237 int slots = 0;
238 int drop_err = 0;
239 int more_data;
240
241 if (!(first->flags & XEN_NETTXF_more_data))
242 return 0;
243
244 do {
245 struct xen_netif_tx_request dropped_tx = { 0 };
246
247 if (slots >= work_to_do) {
248 netdev_err(queue->vif->dev,
249 "Asked for %d slots but exceeds this limit\n",
250 work_to_do);
251 xenvif_fatal_tx_err(queue->vif);
252 return -ENODATA;
253 }
254
255 /* This guest is really using too many slots and
256 * considered malicious.
257 */
258 if (unlikely(slots >= fatal_skb_slots)) {
259 netdev_err(queue->vif->dev,
260 "Malicious frontend using %d slots, threshold %u\n",
261 slots, fatal_skb_slots);
262 xenvif_fatal_tx_err(queue->vif);
263 return -E2BIG;
264 }
265
266 /* Xen network protocol had implicit dependency on
267 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
268 * the historical MAX_SKB_FRAGS value 18 to honor the
269 * same behavior as before. Any packet using more than
270 * 18 slots but less than fatal_skb_slots slots is
271 * dropped
272 */
273 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
274 if (net_ratelimit())
275 netdev_dbg(queue->vif->dev,
276 "Too many slots (%d) exceeding limit (%d), dropping packet\n",
277 slots, XEN_NETBK_LEGACY_SLOTS_MAX);
278 drop_err = -E2BIG;
279 }
280
281 if (drop_err)
282 txp = &dropped_tx;
283
284 RING_COPY_REQUEST(&queue->tx, cons + slots, txp);
285
286 /* If the guest submitted a frame >= 64 KiB then
287 * first->size overflowed and following slots will
288 * appear to be larger than the frame.
289 *
290 * This cannot be fatal error as there are buggy
291 * frontends that do this.
292 *
293 * Consume all slots and drop the packet.
294 */
295 if (!drop_err && txp->size > first->size) {
296 if (net_ratelimit())
297 netdev_dbg(queue->vif->dev,
298 "Invalid tx request, slot size %u > remaining size %u\n",
299 txp->size, first->size);
300 drop_err = -EIO;
301 }
302
303 first->size -= txp->size;
304 slots++;
305
306 if (unlikely((txp->offset + txp->size) > XEN_PAGE_SIZE)) {
307 netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %u, size: %u\n",
308 txp->offset, txp->size);
309 xenvif_fatal_tx_err(queue->vif);
310 return -EINVAL;
311 }
312
313 more_data = txp->flags & XEN_NETTXF_more_data;
314
315 if (!drop_err)
316 txp++;
317
318 } while (more_data);
319
320 if (drop_err) {
321 xenvif_tx_err(queue, first, extra_count, cons + slots);
322 return drop_err;
323 }
324
325 return slots;
326}
327
328
329struct xenvif_tx_cb {
330 u16 copy_pending_idx[XEN_NETBK_LEGACY_SLOTS_MAX + 1];
331 u8 copy_count;
332 u32 split_mask;
333};
334
335#define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
336#define copy_pending_idx(skb, i) (XENVIF_TX_CB(skb)->copy_pending_idx[i])
337#define copy_count(skb) (XENVIF_TX_CB(skb)->copy_count)
338
339static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
340 u16 pending_idx,
341 struct xen_netif_tx_request *txp,
342 unsigned int extra_count,
343 struct gnttab_map_grant_ref *mop)
344{
345 queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
346 gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
347 GNTMAP_host_map | GNTMAP_readonly,
348 txp->gref, queue->vif->domid);
349
350 memcpy(&queue->pending_tx_info[pending_idx].req, txp,
351 sizeof(*txp));
352 queue->pending_tx_info[pending_idx].extra_count = extra_count;
353}
354
355static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
356{
357 struct sk_buff *skb =
358 alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
359 GFP_ATOMIC | __GFP_NOWARN);
360
361 BUILD_BUG_ON(sizeof(*XENVIF_TX_CB(skb)) > sizeof(skb->cb));
362 if (unlikely(skb == NULL))
363 return NULL;
364
365 /* Packets passed to netif_rx() must have some headroom. */
366 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
367
368 /* Initialize it here to avoid later surprises */
369 skb_shinfo(skb)->destructor_arg = NULL;
370
371 return skb;
372}
373
374static void xenvif_get_requests(struct xenvif_queue *queue,
375 struct sk_buff *skb,
376 struct xen_netif_tx_request *first,
377 struct xen_netif_tx_request *txfrags,
378 unsigned *copy_ops,
379 unsigned *map_ops,
380 unsigned int frag_overflow,
381 struct sk_buff *nskb,
382 unsigned int extra_count,
383 unsigned int data_len)
384{
385 struct skb_shared_info *shinfo = skb_shinfo(skb);
386 skb_frag_t *frags = shinfo->frags;
387 u16 pending_idx;
388 pending_ring_idx_t index;
389 unsigned int nr_slots;
390 struct gnttab_copy *cop = queue->tx_copy_ops + *copy_ops;
391 struct gnttab_map_grant_ref *gop = queue->tx_map_ops + *map_ops;
392 struct xen_netif_tx_request *txp = first;
393
394 nr_slots = shinfo->nr_frags + frag_overflow + 1;
395
396 copy_count(skb) = 0;
397 XENVIF_TX_CB(skb)->split_mask = 0;
398
399 /* Create copy ops for exactly data_len bytes into the skb head. */
400 __skb_put(skb, data_len);
401 while (data_len > 0) {
402 int amount = data_len > txp->size ? txp->size : data_len;
403 bool split = false;
404
405 cop->source.u.ref = txp->gref;
406 cop->source.domid = queue->vif->domid;
407 cop->source.offset = txp->offset;
408
409 cop->dest.domid = DOMID_SELF;
410 cop->dest.offset = (offset_in_page(skb->data +
411 skb_headlen(skb) -
412 data_len)) & ~XEN_PAGE_MASK;
413 cop->dest.u.gmfn = virt_to_gfn(skb->data + skb_headlen(skb)
414 - data_len);
415
416 /* Don't cross local page boundary! */
417 if (cop->dest.offset + amount > XEN_PAGE_SIZE) {
418 amount = XEN_PAGE_SIZE - cop->dest.offset;
419 XENVIF_TX_CB(skb)->split_mask |= 1U << copy_count(skb);
420 split = true;
421 }
422
423 cop->len = amount;
424 cop->flags = GNTCOPY_source_gref;
425
426 index = pending_index(queue->pending_cons);
427 pending_idx = queue->pending_ring[index];
428 callback_param(queue, pending_idx).ctx = NULL;
429 copy_pending_idx(skb, copy_count(skb)) = pending_idx;
430 if (!split)
431 copy_count(skb)++;
432
433 cop++;
434 data_len -= amount;
435
436 if (amount == txp->size) {
437 /* The copy op covered the full tx_request */
438
439 memcpy(&queue->pending_tx_info[pending_idx].req,
440 txp, sizeof(*txp));
441 queue->pending_tx_info[pending_idx].extra_count =
442 (txp == first) ? extra_count : 0;
443
444 if (txp == first)
445 txp = txfrags;
446 else
447 txp++;
448 queue->pending_cons++;
449 nr_slots--;
450 } else {
451 /* The copy op partially covered the tx_request.
452 * The remainder will be mapped or copied in the next
453 * iteration.
454 */
455 txp->offset += amount;
456 txp->size -= amount;
457 }
458 }
459
460 for (shinfo->nr_frags = 0; nr_slots > 0 && shinfo->nr_frags < MAX_SKB_FRAGS;
461 nr_slots--) {
462 if (unlikely(!txp->size)) {
463 make_tx_response(queue, txp, 0, XEN_NETIF_RSP_OKAY);
464 ++txp;
465 continue;
466 }
467
468 index = pending_index(queue->pending_cons++);
469 pending_idx = queue->pending_ring[index];
470 xenvif_tx_create_map_op(queue, pending_idx, txp,
471 txp == first ? extra_count : 0, gop);
472 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
473 ++shinfo->nr_frags;
474 ++gop;
475
476 if (txp == first)
477 txp = txfrags;
478 else
479 txp++;
480 }
481
482 if (nr_slots > 0) {
483
484 shinfo = skb_shinfo(nskb);
485 frags = shinfo->frags;
486
487 for (shinfo->nr_frags = 0; shinfo->nr_frags < nr_slots; ++txp) {
488 if (unlikely(!txp->size)) {
489 make_tx_response(queue, txp, 0,
490 XEN_NETIF_RSP_OKAY);
491 continue;
492 }
493
494 index = pending_index(queue->pending_cons++);
495 pending_idx = queue->pending_ring[index];
496 xenvif_tx_create_map_op(queue, pending_idx, txp, 0,
497 gop);
498 frag_set_pending_idx(&frags[shinfo->nr_frags],
499 pending_idx);
500 ++shinfo->nr_frags;
501 ++gop;
502 }
503
504 if (shinfo->nr_frags) {
505 skb_shinfo(skb)->frag_list = nskb;
506 nskb = NULL;
507 }
508 }
509
510 if (nskb) {
511 /* A frag_list skb was allocated but it is no longer needed
512 * because enough slots were converted to copy ops above or some
513 * were empty.
514 */
515 kfree_skb(nskb);
516 }
517
518 (*copy_ops) = cop - queue->tx_copy_ops;
519 (*map_ops) = gop - queue->tx_map_ops;
520}
521
522static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
523 u16 pending_idx,
524 grant_handle_t handle)
525{
526 if (unlikely(queue->grant_tx_handle[pending_idx] !=
527 NETBACK_INVALID_HANDLE)) {
528 netdev_err(queue->vif->dev,
529 "Trying to overwrite active handle! pending_idx: 0x%x\n",
530 pending_idx);
531 BUG();
532 }
533 queue->grant_tx_handle[pending_idx] = handle;
534}
535
536static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
537 u16 pending_idx)
538{
539 if (unlikely(queue->grant_tx_handle[pending_idx] ==
540 NETBACK_INVALID_HANDLE)) {
541 netdev_err(queue->vif->dev,
542 "Trying to unmap invalid handle! pending_idx: 0x%x\n",
543 pending_idx);
544 BUG();
545 }
546 queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
547}
548
549static int xenvif_tx_check_gop(struct xenvif_queue *queue,
550 struct sk_buff *skb,
551 struct gnttab_map_grant_ref **gopp_map,
552 struct gnttab_copy **gopp_copy)
553{
554 struct gnttab_map_grant_ref *gop_map = *gopp_map;
555 u16 pending_idx;
556 /* This always points to the shinfo of the skb being checked, which
557 * could be either the first or the one on the frag_list
558 */
559 struct skb_shared_info *shinfo = skb_shinfo(skb);
560 /* If this is non-NULL, we are currently checking the frag_list skb, and
561 * this points to the shinfo of the first one
562 */
563 struct skb_shared_info *first_shinfo = NULL;
564 int nr_frags = shinfo->nr_frags;
565 const bool sharedslot = nr_frags &&
566 frag_get_pending_idx(&shinfo->frags[0]) ==
567 copy_pending_idx(skb, copy_count(skb) - 1);
568 int i, err = 0;
569
570 for (i = 0; i < copy_count(skb); i++) {
571 int newerr;
572
573 /* Check status of header. */
574 pending_idx = copy_pending_idx(skb, i);
575
576 newerr = (*gopp_copy)->status;
577
578 /* Split copies need to be handled together. */
579 if (XENVIF_TX_CB(skb)->split_mask & (1U << i)) {
580 (*gopp_copy)++;
581 if (!newerr)
582 newerr = (*gopp_copy)->status;
583 }
584 if (likely(!newerr)) {
585 /* The first frag might still have this slot mapped */
586 if (i < copy_count(skb) - 1 || !sharedslot)
587 xenvif_idx_release(queue, pending_idx,
588 XEN_NETIF_RSP_OKAY);
589 } else {
590 err = newerr;
591 if (net_ratelimit())
592 netdev_dbg(queue->vif->dev,
593 "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
594 (*gopp_copy)->status,
595 pending_idx,
596 (*gopp_copy)->source.u.ref);
597 /* The first frag might still have this slot mapped */
598 if (i < copy_count(skb) - 1 || !sharedslot)
599 xenvif_idx_release(queue, pending_idx,
600 XEN_NETIF_RSP_ERROR);
601 }
602 (*gopp_copy)++;
603 }
604
605check_frags:
606 for (i = 0; i < nr_frags; i++, gop_map++) {
607 int j, newerr;
608
609 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
610
611 /* Check error status: if okay then remember grant handle. */
612 newerr = gop_map->status;
613
614 if (likely(!newerr)) {
615 xenvif_grant_handle_set(queue,
616 pending_idx,
617 gop_map->handle);
618 /* Had a previous error? Invalidate this fragment. */
619 if (unlikely(err)) {
620 xenvif_idx_unmap(queue, pending_idx);
621 /* If the mapping of the first frag was OK, but
622 * the header's copy failed, and they are
623 * sharing a slot, send an error
624 */
625 if (i == 0 && !first_shinfo && sharedslot)
626 xenvif_idx_release(queue, pending_idx,
627 XEN_NETIF_RSP_ERROR);
628 else
629 xenvif_idx_release(queue, pending_idx,
630 XEN_NETIF_RSP_OKAY);
631 }
632 continue;
633 }
634
635 /* Error on this fragment: respond to client with an error. */
636 if (net_ratelimit())
637 netdev_dbg(queue->vif->dev,
638 "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
639 i,
640 gop_map->status,
641 pending_idx,
642 gop_map->ref);
643
644 xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
645
646 /* Not the first error? Preceding frags already invalidated. */
647 if (err)
648 continue;
649
650 /* Invalidate preceding fragments of this skb. */
651 for (j = 0; j < i; j++) {
652 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
653 xenvif_idx_unmap(queue, pending_idx);
654 xenvif_idx_release(queue, pending_idx,
655 XEN_NETIF_RSP_OKAY);
656 }
657
658 /* And if we found the error while checking the frag_list, unmap
659 * the first skb's frags
660 */
661 if (first_shinfo) {
662 for (j = 0; j < first_shinfo->nr_frags; j++) {
663 pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
664 xenvif_idx_unmap(queue, pending_idx);
665 xenvif_idx_release(queue, pending_idx,
666 XEN_NETIF_RSP_OKAY);
667 }
668 }
669
670 /* Remember the error: invalidate all subsequent fragments. */
671 err = newerr;
672 }
673
674 if (skb_has_frag_list(skb) && !first_shinfo) {
675 first_shinfo = shinfo;
676 shinfo = skb_shinfo(shinfo->frag_list);
677 nr_frags = shinfo->nr_frags;
678
679 goto check_frags;
680 }
681
682 *gopp_map = gop_map;
683 return err;
684}
685
686static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
687{
688 struct skb_shared_info *shinfo = skb_shinfo(skb);
689 int nr_frags = shinfo->nr_frags;
690 int i;
691 u16 prev_pending_idx = INVALID_PENDING_IDX;
692
693 for (i = 0; i < nr_frags; i++) {
694 skb_frag_t *frag = shinfo->frags + i;
695 struct xen_netif_tx_request *txp;
696 struct page *page;
697 u16 pending_idx;
698
699 pending_idx = frag_get_pending_idx(frag);
700
701 /* If this is not the first frag, chain it to the previous*/
702 if (prev_pending_idx == INVALID_PENDING_IDX)
703 skb_shinfo(skb)->destructor_arg =
704 &callback_param(queue, pending_idx);
705 else
706 callback_param(queue, prev_pending_idx).ctx =
707 &callback_param(queue, pending_idx);
708
709 callback_param(queue, pending_idx).ctx = NULL;
710 prev_pending_idx = pending_idx;
711
712 txp = &queue->pending_tx_info[pending_idx].req;
713 page = virt_to_page((void *)idx_to_kaddr(queue, pending_idx));
714 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
715 skb->len += txp->size;
716 skb->data_len += txp->size;
717 skb->truesize += txp->size;
718
719 /* Take an extra reference to offset network stack's put_page */
720 get_page(queue->mmap_pages[pending_idx]);
721 }
722}
723
724static int xenvif_get_extras(struct xenvif_queue *queue,
725 struct xen_netif_extra_info *extras,
726 unsigned int *extra_count,
727 int work_to_do)
728{
729 struct xen_netif_extra_info extra;
730 RING_IDX cons = queue->tx.req_cons;
731
732 do {
733 if (unlikely(work_to_do-- <= 0)) {
734 netdev_err(queue->vif->dev, "Missing extra info\n");
735 xenvif_fatal_tx_err(queue->vif);
736 return -EBADR;
737 }
738
739 RING_COPY_REQUEST(&queue->tx, cons, &extra);
740
741 queue->tx.req_cons = ++cons;
742 (*extra_count)++;
743
744 if (unlikely(!extra.type ||
745 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
746 netdev_err(queue->vif->dev,
747 "Invalid extra type: %d\n", extra.type);
748 xenvif_fatal_tx_err(queue->vif);
749 return -EINVAL;
750 }
751
752 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
753 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
754
755 return work_to_do;
756}
757
758static int xenvif_set_skb_gso(struct xenvif *vif,
759 struct sk_buff *skb,
760 struct xen_netif_extra_info *gso)
761{
762 if (!gso->u.gso.size) {
763 netdev_err(vif->dev, "GSO size must not be zero.\n");
764 xenvif_fatal_tx_err(vif);
765 return -EINVAL;
766 }
767
768 switch (gso->u.gso.type) {
769 case XEN_NETIF_GSO_TYPE_TCPV4:
770 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
771 break;
772 case XEN_NETIF_GSO_TYPE_TCPV6:
773 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
774 break;
775 default:
776 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
777 xenvif_fatal_tx_err(vif);
778 return -EINVAL;
779 }
780
781 skb_shinfo(skb)->gso_size = gso->u.gso.size;
782 /* gso_segs will be calculated later */
783
784 return 0;
785}
786
787static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb)
788{
789 bool recalculate_partial_csum = false;
790
791 /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
792 * peers can fail to set NETRXF_csum_blank when sending a GSO
793 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
794 * recalculate the partial checksum.
795 */
796 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
797 queue->stats.rx_gso_checksum_fixup++;
798 skb->ip_summed = CHECKSUM_PARTIAL;
799 recalculate_partial_csum = true;
800 }
801
802 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
803 if (skb->ip_summed != CHECKSUM_PARTIAL)
804 return 0;
805
806 return skb_checksum_setup(skb, recalculate_partial_csum);
807}
808
809static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
810{
811 u64 now = get_jiffies_64();
812 u64 next_credit = queue->credit_window_start +
813 msecs_to_jiffies(queue->credit_usec / 1000);
814
815 /* Timer could already be pending in rare cases. */
816 if (timer_pending(&queue->credit_timeout)) {
817 queue->rate_limited = true;
818 return true;
819 }
820
821 /* Passed the point where we can replenish credit? */
822 if (time_after_eq64(now, next_credit)) {
823 queue->credit_window_start = now;
824 tx_add_credit(queue);
825 }
826
827 /* Still too big to send right now? Set a callback. */
828 if (size > queue->remaining_credit) {
829 mod_timer(&queue->credit_timeout,
830 next_credit);
831 queue->credit_window_start = next_credit;
832 queue->rate_limited = true;
833
834 return true;
835 }
836
837 return false;
838}
839
840/* No locking is required in xenvif_mcast_add/del() as they are
841 * only ever invoked from NAPI poll. An RCU list is used because
842 * xenvif_mcast_match() is called asynchronously, during start_xmit.
843 */
844
845static int xenvif_mcast_add(struct xenvif *vif, const u8 *addr)
846{
847 struct xenvif_mcast_addr *mcast;
848
849 if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) {
850 if (net_ratelimit())
851 netdev_err(vif->dev,
852 "Too many multicast addresses\n");
853 return -ENOSPC;
854 }
855
856 mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC);
857 if (!mcast)
858 return -ENOMEM;
859
860 ether_addr_copy(mcast->addr, addr);
861 list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr);
862 vif->fe_mcast_count++;
863
864 return 0;
865}
866
867static void xenvif_mcast_del(struct xenvif *vif, const u8 *addr)
868{
869 struct xenvif_mcast_addr *mcast;
870
871 list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
872 if (ether_addr_equal(addr, mcast->addr)) {
873 --vif->fe_mcast_count;
874 list_del_rcu(&mcast->entry);
875 kfree_rcu(mcast, rcu);
876 break;
877 }
878 }
879}
880
881bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr)
882{
883 struct xenvif_mcast_addr *mcast;
884
885 rcu_read_lock();
886 list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
887 if (ether_addr_equal(addr, mcast->addr)) {
888 rcu_read_unlock();
889 return true;
890 }
891 }
892 rcu_read_unlock();
893
894 return false;
895}
896
897void xenvif_mcast_addr_list_free(struct xenvif *vif)
898{
899 /* No need for locking or RCU here. NAPI poll and TX queue
900 * are stopped.
901 */
902 while (!list_empty(&vif->fe_mcast_addr)) {
903 struct xenvif_mcast_addr *mcast;
904
905 mcast = list_first_entry(&vif->fe_mcast_addr,
906 struct xenvif_mcast_addr,
907 entry);
908 --vif->fe_mcast_count;
909 list_del(&mcast->entry);
910 kfree(mcast);
911 }
912}
913
914static void xenvif_tx_build_gops(struct xenvif_queue *queue,
915 int budget,
916 unsigned *copy_ops,
917 unsigned *map_ops)
918{
919 struct sk_buff *skb, *nskb;
920 int ret;
921 unsigned int frag_overflow;
922
923 while (skb_queue_len(&queue->tx_queue) < budget) {
924 struct xen_netif_tx_request txreq;
925 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
926 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
927 unsigned int extra_count;
928 RING_IDX idx;
929 int work_to_do;
930 unsigned int data_len;
931
932 if (queue->tx.sring->req_prod - queue->tx.req_cons >
933 XEN_NETIF_TX_RING_SIZE) {
934 netdev_err(queue->vif->dev,
935 "Impossible number of requests. "
936 "req_prod %d, req_cons %d, size %ld\n",
937 queue->tx.sring->req_prod, queue->tx.req_cons,
938 XEN_NETIF_TX_RING_SIZE);
939 xenvif_fatal_tx_err(queue->vif);
940 break;
941 }
942
943 work_to_do = XEN_RING_NR_UNCONSUMED_REQUESTS(&queue->tx);
944 if (!work_to_do)
945 break;
946
947 idx = queue->tx.req_cons;
948 rmb(); /* Ensure that we see the request before we copy it. */
949 RING_COPY_REQUEST(&queue->tx, idx, &txreq);
950
951 /* Credit-based scheduling. */
952 if (txreq.size > queue->remaining_credit &&
953 tx_credit_exceeded(queue, txreq.size))
954 break;
955
956 queue->remaining_credit -= txreq.size;
957
958 work_to_do--;
959 queue->tx.req_cons = ++idx;
960
961 memset(extras, 0, sizeof(extras));
962 extra_count = 0;
963 if (txreq.flags & XEN_NETTXF_extra_info) {
964 work_to_do = xenvif_get_extras(queue, extras,
965 &extra_count,
966 work_to_do);
967 idx = queue->tx.req_cons;
968 if (unlikely(work_to_do < 0))
969 break;
970 }
971
972 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) {
973 struct xen_netif_extra_info *extra;
974
975 extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
976 ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
977
978 make_tx_response(queue, &txreq, extra_count,
979 (ret == 0) ?
980 XEN_NETIF_RSP_OKAY :
981 XEN_NETIF_RSP_ERROR);
982 continue;
983 }
984
985 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) {
986 struct xen_netif_extra_info *extra;
987
988 extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
989 xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
990
991 make_tx_response(queue, &txreq, extra_count,
992 XEN_NETIF_RSP_OKAY);
993 continue;
994 }
995
996 data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN) ?
997 XEN_NETBACK_TX_COPY_LEN : txreq.size;
998
999 ret = xenvif_count_requests(queue, &txreq, extra_count,
1000 txfrags, work_to_do);
1001
1002 if (unlikely(ret < 0))
1003 break;
1004
1005 idx += ret;
1006
1007 if (unlikely(txreq.size < ETH_HLEN)) {
1008 netdev_dbg(queue->vif->dev,
1009 "Bad packet size: %d\n", txreq.size);
1010 xenvif_tx_err(queue, &txreq, extra_count, idx);
1011 break;
1012 }
1013
1014 /* No crossing a page as the payload mustn't fragment. */
1015 if (unlikely((txreq.offset + txreq.size) > XEN_PAGE_SIZE)) {
1016 netdev_err(queue->vif->dev, "Cross page boundary, txreq.offset: %u, size: %u\n",
1017 txreq.offset, txreq.size);
1018 xenvif_fatal_tx_err(queue->vif);
1019 break;
1020 }
1021
1022 if (ret >= XEN_NETBK_LEGACY_SLOTS_MAX - 1 && data_len < txreq.size)
1023 data_len = txreq.size;
1024
1025 skb = xenvif_alloc_skb(data_len);
1026 if (unlikely(skb == NULL)) {
1027 netdev_dbg(queue->vif->dev,
1028 "Can't allocate a skb in start_xmit.\n");
1029 xenvif_tx_err(queue, &txreq, extra_count, idx);
1030 break;
1031 }
1032
1033 skb_shinfo(skb)->nr_frags = ret;
1034 /* At this point shinfo->nr_frags is in fact the number of
1035 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
1036 */
1037 frag_overflow = 0;
1038 nskb = NULL;
1039 if (skb_shinfo(skb)->nr_frags > MAX_SKB_FRAGS) {
1040 frag_overflow = skb_shinfo(skb)->nr_frags - MAX_SKB_FRAGS;
1041 BUG_ON(frag_overflow > MAX_SKB_FRAGS);
1042 skb_shinfo(skb)->nr_frags = MAX_SKB_FRAGS;
1043 nskb = xenvif_alloc_skb(0);
1044 if (unlikely(nskb == NULL)) {
1045 skb_shinfo(skb)->nr_frags = 0;
1046 kfree_skb(skb);
1047 xenvif_tx_err(queue, &txreq, extra_count, idx);
1048 if (net_ratelimit())
1049 netdev_err(queue->vif->dev,
1050 "Can't allocate the frag_list skb.\n");
1051 break;
1052 }
1053 }
1054
1055 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1056 struct xen_netif_extra_info *gso;
1057 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1058
1059 if (xenvif_set_skb_gso(queue->vif, skb, gso)) {
1060 /* Failure in xenvif_set_skb_gso is fatal. */
1061 skb_shinfo(skb)->nr_frags = 0;
1062 kfree_skb(skb);
1063 kfree_skb(nskb);
1064 break;
1065 }
1066 }
1067
1068 if (extras[XEN_NETIF_EXTRA_TYPE_HASH - 1].type) {
1069 struct xen_netif_extra_info *extra;
1070 enum pkt_hash_types type = PKT_HASH_TYPE_NONE;
1071
1072 extra = &extras[XEN_NETIF_EXTRA_TYPE_HASH - 1];
1073
1074 switch (extra->u.hash.type) {
1075 case _XEN_NETIF_CTRL_HASH_TYPE_IPV4:
1076 case _XEN_NETIF_CTRL_HASH_TYPE_IPV6:
1077 type = PKT_HASH_TYPE_L3;
1078 break;
1079
1080 case _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP:
1081 case _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP:
1082 type = PKT_HASH_TYPE_L4;
1083 break;
1084
1085 default:
1086 break;
1087 }
1088
1089 if (type != PKT_HASH_TYPE_NONE)
1090 skb_set_hash(skb,
1091 *(u32 *)extra->u.hash.value,
1092 type);
1093 }
1094
1095 xenvif_get_requests(queue, skb, &txreq, txfrags, copy_ops,
1096 map_ops, frag_overflow, nskb, extra_count,
1097 data_len);
1098
1099 __skb_queue_tail(&queue->tx_queue, skb);
1100
1101 queue->tx.req_cons = idx;
1102 }
1103
1104 return;
1105}
1106
1107/* Consolidate skb with a frag_list into a brand new one with local pages on
1108 * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1109 */
1110static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb)
1111{
1112 unsigned int offset = skb_headlen(skb);
1113 skb_frag_t frags[MAX_SKB_FRAGS];
1114 int i, f;
1115 struct ubuf_info *uarg;
1116 struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1117
1118 queue->stats.tx_zerocopy_sent += 2;
1119 queue->stats.tx_frag_overflow++;
1120
1121 xenvif_fill_frags(queue, nskb);
1122 /* Subtract frags size, we will correct it later */
1123 skb->truesize -= skb->data_len;
1124 skb->len += nskb->len;
1125 skb->data_len += nskb->len;
1126
1127 /* create a brand new frags array and coalesce there */
1128 for (i = 0; offset < skb->len; i++) {
1129 struct page *page;
1130 unsigned int len;
1131
1132 BUG_ON(i >= MAX_SKB_FRAGS);
1133 page = alloc_page(GFP_ATOMIC);
1134 if (!page) {
1135 int j;
1136 skb->truesize += skb->data_len;
1137 for (j = 0; j < i; j++)
1138 put_page(skb_frag_page(&frags[j]));
1139 return -ENOMEM;
1140 }
1141
1142 if (offset + PAGE_SIZE < skb->len)
1143 len = PAGE_SIZE;
1144 else
1145 len = skb->len - offset;
1146 if (skb_copy_bits(skb, offset, page_address(page), len))
1147 BUG();
1148
1149 offset += len;
1150 skb_frag_fill_page_desc(&frags[i], page, 0, len);
1151 }
1152
1153 /* Release all the original (foreign) frags. */
1154 for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
1155 skb_frag_unref(skb, f);
1156 uarg = skb_shinfo(skb)->destructor_arg;
1157 /* increase inflight counter to offset decrement in callback */
1158 atomic_inc(&queue->inflight_packets);
1159 uarg->callback(NULL, uarg, true);
1160 skb_shinfo(skb)->destructor_arg = NULL;
1161
1162 /* Fill the skb with the new (local) frags. */
1163 memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t));
1164 skb_shinfo(skb)->nr_frags = i;
1165 skb->truesize += i * PAGE_SIZE;
1166
1167 return 0;
1168}
1169
1170static int xenvif_tx_submit(struct xenvif_queue *queue)
1171{
1172 struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops;
1173 struct gnttab_copy *gop_copy = queue->tx_copy_ops;
1174 struct sk_buff *skb;
1175 int work_done = 0;
1176
1177 while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
1178 struct xen_netif_tx_request *txp;
1179 u16 pending_idx;
1180
1181 pending_idx = copy_pending_idx(skb, 0);
1182 txp = &queue->pending_tx_info[pending_idx].req;
1183
1184 /* Check the remap error code. */
1185 if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
1186 /* If there was an error, xenvif_tx_check_gop is
1187 * expected to release all the frags which were mapped,
1188 * so kfree_skb shouldn't do it again
1189 */
1190 skb_shinfo(skb)->nr_frags = 0;
1191 if (skb_has_frag_list(skb)) {
1192 struct sk_buff *nskb =
1193 skb_shinfo(skb)->frag_list;
1194 skb_shinfo(nskb)->nr_frags = 0;
1195 }
1196 kfree_skb(skb);
1197 continue;
1198 }
1199
1200 if (txp->flags & XEN_NETTXF_csum_blank)
1201 skb->ip_summed = CHECKSUM_PARTIAL;
1202 else if (txp->flags & XEN_NETTXF_data_validated)
1203 skb->ip_summed = CHECKSUM_UNNECESSARY;
1204
1205 xenvif_fill_frags(queue, skb);
1206
1207 if (unlikely(skb_has_frag_list(skb))) {
1208 struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1209 xenvif_skb_zerocopy_prepare(queue, nskb);
1210 if (xenvif_handle_frag_list(queue, skb)) {
1211 if (net_ratelimit())
1212 netdev_err(queue->vif->dev,
1213 "Not enough memory to consolidate frag_list!\n");
1214 xenvif_skb_zerocopy_prepare(queue, skb);
1215 kfree_skb(skb);
1216 continue;
1217 }
1218 /* Copied all the bits from the frag list -- free it. */
1219 skb_frag_list_init(skb);
1220 kfree_skb(nskb);
1221 }
1222
1223 skb->dev = queue->vif->dev;
1224 skb->protocol = eth_type_trans(skb, skb->dev);
1225 skb_reset_network_header(skb);
1226
1227 if (checksum_setup(queue, skb)) {
1228 netdev_dbg(queue->vif->dev,
1229 "Can't setup checksum in net_tx_action\n");
1230 /* We have to set this flag to trigger the callback */
1231 if (skb_shinfo(skb)->destructor_arg)
1232 xenvif_skb_zerocopy_prepare(queue, skb);
1233 kfree_skb(skb);
1234 continue;
1235 }
1236
1237 skb_probe_transport_header(skb);
1238
1239 /* If the packet is GSO then we will have just set up the
1240 * transport header offset in checksum_setup so it's now
1241 * straightforward to calculate gso_segs.
1242 */
1243 if (skb_is_gso(skb)) {
1244 int mss, hdrlen;
1245
1246 /* GSO implies having the L4 header. */
1247 WARN_ON_ONCE(!skb_transport_header_was_set(skb));
1248 if (unlikely(!skb_transport_header_was_set(skb))) {
1249 kfree_skb(skb);
1250 continue;
1251 }
1252
1253 mss = skb_shinfo(skb)->gso_size;
1254 hdrlen = skb_tcp_all_headers(skb);
1255
1256 skb_shinfo(skb)->gso_segs =
1257 DIV_ROUND_UP(skb->len - hdrlen, mss);
1258 }
1259
1260 queue->stats.rx_bytes += skb->len;
1261 queue->stats.rx_packets++;
1262
1263 work_done++;
1264
1265 /* Set this flag right before netif_receive_skb, otherwise
1266 * someone might think this packet already left netback, and
1267 * do a skb_copy_ubufs while we are still in control of the
1268 * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1269 */
1270 if (skb_shinfo(skb)->destructor_arg) {
1271 xenvif_skb_zerocopy_prepare(queue, skb);
1272 queue->stats.tx_zerocopy_sent++;
1273 }
1274
1275 netif_receive_skb(skb);
1276 }
1277
1278 return work_done;
1279}
1280
1281void xenvif_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *ubuf_base,
1282 bool zerocopy_success)
1283{
1284 unsigned long flags;
1285 pending_ring_idx_t index;
1286 struct ubuf_info_msgzc *ubuf = uarg_to_msgzc(ubuf_base);
1287 struct xenvif_queue *queue = ubuf_to_queue(ubuf);
1288
1289 /* This is the only place where we grab this lock, to protect callbacks
1290 * from each other.
1291 */
1292 spin_lock_irqsave(&queue->callback_lock, flags);
1293 do {
1294 u16 pending_idx = ubuf->desc;
1295 ubuf = (struct ubuf_info_msgzc *) ubuf->ctx;
1296 BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
1297 MAX_PENDING_REQS);
1298 index = pending_index(queue->dealloc_prod);
1299 queue->dealloc_ring[index] = pending_idx;
1300 /* Sync with xenvif_tx_dealloc_action:
1301 * insert idx then incr producer.
1302 */
1303 smp_wmb();
1304 queue->dealloc_prod++;
1305 } while (ubuf);
1306 spin_unlock_irqrestore(&queue->callback_lock, flags);
1307
1308 if (likely(zerocopy_success))
1309 queue->stats.tx_zerocopy_success++;
1310 else
1311 queue->stats.tx_zerocopy_fail++;
1312 xenvif_skb_zerocopy_complete(queue);
1313}
1314
1315static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
1316{
1317 struct gnttab_unmap_grant_ref *gop;
1318 pending_ring_idx_t dc, dp;
1319 u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1320 unsigned int i = 0;
1321
1322 dc = queue->dealloc_cons;
1323 gop = queue->tx_unmap_ops;
1324
1325 /* Free up any grants we have finished using */
1326 do {
1327 dp = queue->dealloc_prod;
1328
1329 /* Ensure we see all indices enqueued by all
1330 * xenvif_zerocopy_callback().
1331 */
1332 smp_rmb();
1333
1334 while (dc != dp) {
1335 BUG_ON(gop - queue->tx_unmap_ops >= MAX_PENDING_REQS);
1336 pending_idx =
1337 queue->dealloc_ring[pending_index(dc++)];
1338
1339 pending_idx_release[gop - queue->tx_unmap_ops] =
1340 pending_idx;
1341 queue->pages_to_unmap[gop - queue->tx_unmap_ops] =
1342 queue->mmap_pages[pending_idx];
1343 gnttab_set_unmap_op(gop,
1344 idx_to_kaddr(queue, pending_idx),
1345 GNTMAP_host_map,
1346 queue->grant_tx_handle[pending_idx]);
1347 xenvif_grant_handle_reset(queue, pending_idx);
1348 ++gop;
1349 }
1350
1351 } while (dp != queue->dealloc_prod);
1352
1353 queue->dealloc_cons = dc;
1354
1355 if (gop - queue->tx_unmap_ops > 0) {
1356 int ret;
1357 ret = gnttab_unmap_refs(queue->tx_unmap_ops,
1358 NULL,
1359 queue->pages_to_unmap,
1360 gop - queue->tx_unmap_ops);
1361 if (ret) {
1362 netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tu ret %d\n",
1363 gop - queue->tx_unmap_ops, ret);
1364 for (i = 0; i < gop - queue->tx_unmap_ops; ++i) {
1365 if (gop[i].status != GNTST_okay)
1366 netdev_err(queue->vif->dev,
1367 " host_addr: 0x%llx handle: 0x%x status: %d\n",
1368 gop[i].host_addr,
1369 gop[i].handle,
1370 gop[i].status);
1371 }
1372 BUG();
1373 }
1374 }
1375
1376 for (i = 0; i < gop - queue->tx_unmap_ops; ++i)
1377 xenvif_idx_release(queue, pending_idx_release[i],
1378 XEN_NETIF_RSP_OKAY);
1379}
1380
1381
1382/* Called after netfront has transmitted */
1383int xenvif_tx_action(struct xenvif_queue *queue, int budget)
1384{
1385 unsigned nr_mops = 0, nr_cops = 0;
1386 int work_done, ret;
1387
1388 if (unlikely(!tx_work_todo(queue)))
1389 return 0;
1390
1391 xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops);
1392
1393 if (nr_cops == 0)
1394 return 0;
1395
1396 gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
1397 if (nr_mops != 0) {
1398 ret = gnttab_map_refs(queue->tx_map_ops,
1399 NULL,
1400 queue->pages_to_map,
1401 nr_mops);
1402 if (ret) {
1403 unsigned int i;
1404
1405 netdev_err(queue->vif->dev, "Map fail: nr %u ret %d\n",
1406 nr_mops, ret);
1407 for (i = 0; i < nr_mops; ++i)
1408 WARN_ON_ONCE(queue->tx_map_ops[i].status ==
1409 GNTST_okay);
1410 }
1411 }
1412
1413 work_done = xenvif_tx_submit(queue);
1414
1415 return work_done;
1416}
1417
1418static void _make_tx_response(struct xenvif_queue *queue,
1419 const struct xen_netif_tx_request *txp,
1420 unsigned int extra_count,
1421 s8 status)
1422{
1423 RING_IDX i = queue->tx.rsp_prod_pvt;
1424 struct xen_netif_tx_response *resp;
1425
1426 resp = RING_GET_RESPONSE(&queue->tx, i);
1427 resp->id = txp->id;
1428 resp->status = status;
1429
1430 while (extra_count-- != 0)
1431 RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1432
1433 queue->tx.rsp_prod_pvt = ++i;
1434}
1435
1436static void push_tx_responses(struct xenvif_queue *queue)
1437{
1438 int notify;
1439
1440 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
1441 if (notify)
1442 notify_remote_via_irq(queue->tx_irq);
1443}
1444
1445static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
1446 s8 status)
1447{
1448 struct pending_tx_info *pending_tx_info;
1449 pending_ring_idx_t index;
1450 unsigned long flags;
1451
1452 pending_tx_info = &queue->pending_tx_info[pending_idx];
1453
1454 spin_lock_irqsave(&queue->response_lock, flags);
1455
1456 _make_tx_response(queue, &pending_tx_info->req,
1457 pending_tx_info->extra_count, status);
1458
1459 /* Release the pending index before pusing the Tx response so
1460 * its available before a new Tx request is pushed by the
1461 * frontend.
1462 */
1463 index = pending_index(queue->pending_prod++);
1464 queue->pending_ring[index] = pending_idx;
1465
1466 push_tx_responses(queue);
1467
1468 spin_unlock_irqrestore(&queue->response_lock, flags);
1469}
1470
1471static void make_tx_response(struct xenvif_queue *queue,
1472 const struct xen_netif_tx_request *txp,
1473 unsigned int extra_count,
1474 s8 status)
1475{
1476 unsigned long flags;
1477
1478 spin_lock_irqsave(&queue->response_lock, flags);
1479
1480 _make_tx_response(queue, txp, extra_count, status);
1481 push_tx_responses(queue);
1482
1483 spin_unlock_irqrestore(&queue->response_lock, flags);
1484}
1485
1486static void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
1487{
1488 int ret;
1489 struct gnttab_unmap_grant_ref tx_unmap_op;
1490
1491 gnttab_set_unmap_op(&tx_unmap_op,
1492 idx_to_kaddr(queue, pending_idx),
1493 GNTMAP_host_map,
1494 queue->grant_tx_handle[pending_idx]);
1495 xenvif_grant_handle_reset(queue, pending_idx);
1496
1497 ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1498 &queue->mmap_pages[pending_idx], 1);
1499 if (ret) {
1500 netdev_err(queue->vif->dev,
1501 "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: 0x%x status: %d\n",
1502 ret,
1503 pending_idx,
1504 tx_unmap_op.host_addr,
1505 tx_unmap_op.handle,
1506 tx_unmap_op.status);
1507 BUG();
1508 }
1509}
1510
1511static inline int tx_work_todo(struct xenvif_queue *queue)
1512{
1513 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
1514 return 1;
1515
1516 return 0;
1517}
1518
1519static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
1520{
1521 return queue->dealloc_cons != queue->dealloc_prod;
1522}
1523
1524void xenvif_unmap_frontend_data_rings(struct xenvif_queue *queue)
1525{
1526 if (queue->tx.sring)
1527 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1528 queue->tx.sring);
1529 if (queue->rx.sring)
1530 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1531 queue->rx.sring);
1532}
1533
1534int xenvif_map_frontend_data_rings(struct xenvif_queue *queue,
1535 grant_ref_t tx_ring_ref,
1536 grant_ref_t rx_ring_ref)
1537{
1538 void *addr;
1539 struct xen_netif_tx_sring *txs;
1540 struct xen_netif_rx_sring *rxs;
1541 RING_IDX rsp_prod, req_prod;
1542 int err;
1543
1544 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1545 &tx_ring_ref, 1, &addr);
1546 if (err)
1547 goto err;
1548
1549 txs = (struct xen_netif_tx_sring *)addr;
1550 rsp_prod = READ_ONCE(txs->rsp_prod);
1551 req_prod = READ_ONCE(txs->req_prod);
1552
1553 BACK_RING_ATTACH(&queue->tx, txs, rsp_prod, XEN_PAGE_SIZE);
1554
1555 err = -EIO;
1556 if (req_prod - rsp_prod > RING_SIZE(&queue->tx))
1557 goto err;
1558
1559 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1560 &rx_ring_ref, 1, &addr);
1561 if (err)
1562 goto err;
1563
1564 rxs = (struct xen_netif_rx_sring *)addr;
1565 rsp_prod = READ_ONCE(rxs->rsp_prod);
1566 req_prod = READ_ONCE(rxs->req_prod);
1567
1568 BACK_RING_ATTACH(&queue->rx, rxs, rsp_prod, XEN_PAGE_SIZE);
1569
1570 err = -EIO;
1571 if (req_prod - rsp_prod > RING_SIZE(&queue->rx))
1572 goto err;
1573
1574 return 0;
1575
1576err:
1577 xenvif_unmap_frontend_data_rings(queue);
1578 return err;
1579}
1580
1581static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue)
1582{
1583 /* Dealloc thread must remain running until all inflight
1584 * packets complete.
1585 */
1586 return kthread_should_stop() &&
1587 !atomic_read(&queue->inflight_packets);
1588}
1589
1590int xenvif_dealloc_kthread(void *data)
1591{
1592 struct xenvif_queue *queue = data;
1593
1594 for (;;) {
1595 wait_event_interruptible(queue->dealloc_wq,
1596 tx_dealloc_work_todo(queue) ||
1597 xenvif_dealloc_kthread_should_stop(queue));
1598 if (xenvif_dealloc_kthread_should_stop(queue))
1599 break;
1600
1601 xenvif_tx_dealloc_action(queue);
1602 cond_resched();
1603 }
1604
1605 /* Unmap anything remaining*/
1606 if (tx_dealloc_work_todo(queue))
1607 xenvif_tx_dealloc_action(queue);
1608
1609 return 0;
1610}
1611
1612static void make_ctrl_response(struct xenvif *vif,
1613 const struct xen_netif_ctrl_request *req,
1614 u32 status, u32 data)
1615{
1616 RING_IDX idx = vif->ctrl.rsp_prod_pvt;
1617 struct xen_netif_ctrl_response rsp = {
1618 .id = req->id,
1619 .type = req->type,
1620 .status = status,
1621 .data = data,
1622 };
1623
1624 *RING_GET_RESPONSE(&vif->ctrl, idx) = rsp;
1625 vif->ctrl.rsp_prod_pvt = ++idx;
1626}
1627
1628static void push_ctrl_response(struct xenvif *vif)
1629{
1630 int notify;
1631
1632 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->ctrl, notify);
1633 if (notify)
1634 notify_remote_via_irq(vif->ctrl_irq);
1635}
1636
1637static void process_ctrl_request(struct xenvif *vif,
1638 const struct xen_netif_ctrl_request *req)
1639{
1640 u32 status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED;
1641 u32 data = 0;
1642
1643 switch (req->type) {
1644 case XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM:
1645 status = xenvif_set_hash_alg(vif, req->data[0]);
1646 break;
1647
1648 case XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS:
1649 status = xenvif_get_hash_flags(vif, &data);
1650 break;
1651
1652 case XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS:
1653 status = xenvif_set_hash_flags(vif, req->data[0]);
1654 break;
1655
1656 case XEN_NETIF_CTRL_TYPE_SET_HASH_KEY:
1657 status = xenvif_set_hash_key(vif, req->data[0],
1658 req->data[1]);
1659 break;
1660
1661 case XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE:
1662 status = XEN_NETIF_CTRL_STATUS_SUCCESS;
1663 data = XEN_NETBK_MAX_HASH_MAPPING_SIZE;
1664 break;
1665
1666 case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE:
1667 status = xenvif_set_hash_mapping_size(vif,
1668 req->data[0]);
1669 break;
1670
1671 case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING:
1672 status = xenvif_set_hash_mapping(vif, req->data[0],
1673 req->data[1],
1674 req->data[2]);
1675 break;
1676
1677 default:
1678 break;
1679 }
1680
1681 make_ctrl_response(vif, req, status, data);
1682 push_ctrl_response(vif);
1683}
1684
1685static void xenvif_ctrl_action(struct xenvif *vif)
1686{
1687 for (;;) {
1688 RING_IDX req_prod, req_cons;
1689
1690 req_prod = vif->ctrl.sring->req_prod;
1691 req_cons = vif->ctrl.req_cons;
1692
1693 /* Make sure we can see requests before we process them. */
1694 rmb();
1695
1696 if (req_cons == req_prod)
1697 break;
1698
1699 while (req_cons != req_prod) {
1700 struct xen_netif_ctrl_request req;
1701
1702 RING_COPY_REQUEST(&vif->ctrl, req_cons, &req);
1703 req_cons++;
1704
1705 process_ctrl_request(vif, &req);
1706 }
1707
1708 vif->ctrl.req_cons = req_cons;
1709 vif->ctrl.sring->req_event = req_cons + 1;
1710 }
1711}
1712
1713static bool xenvif_ctrl_work_todo(struct xenvif *vif)
1714{
1715 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->ctrl)))
1716 return true;
1717
1718 return false;
1719}
1720
1721irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data)
1722{
1723 struct xenvif *vif = data;
1724 unsigned int eoi_flag = XEN_EOI_FLAG_SPURIOUS;
1725
1726 while (xenvif_ctrl_work_todo(vif)) {
1727 xenvif_ctrl_action(vif);
1728 eoi_flag = 0;
1729 }
1730
1731 xen_irq_lateeoi(irq, eoi_flag);
1732
1733 return IRQ_HANDLED;
1734}
1735
1736static int __init netback_init(void)
1737{
1738 int rc = 0;
1739
1740 if (!xen_domain())
1741 return -ENODEV;
1742
1743 /* Allow as many queues as there are CPUs but max. 8 if user has not
1744 * specified a value.
1745 */
1746 if (xenvif_max_queues == 0)
1747 xenvif_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
1748 num_online_cpus());
1749
1750 if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
1751 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
1752 fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
1753 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
1754 }
1755
1756 rc = xenvif_xenbus_init();
1757 if (rc)
1758 goto failed_init;
1759
1760#ifdef CONFIG_DEBUG_FS
1761 xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
1762#endif /* CONFIG_DEBUG_FS */
1763
1764 return 0;
1765
1766failed_init:
1767 return rc;
1768}
1769
1770module_init(netback_init);
1771
1772static void __exit netback_fini(void)
1773{
1774#ifdef CONFIG_DEBUG_FS
1775 debugfs_remove_recursive(xen_netback_dbg_root);
1776#endif /* CONFIG_DEBUG_FS */
1777 xenvif_xenbus_fini();
1778}
1779module_exit(netback_fini);
1780
1781MODULE_DESCRIPTION("Xen backend network device module");
1782MODULE_LICENSE("Dual BSD/GPL");
1783MODULE_ALIAS("xen-backend:vif");
1/*
2 * Back-end of the driver for virtual network devices. This portion of the
3 * driver exports a 'unified' network-device interface that can be accessed
4 * by any operating system that implements a compatible front end. A
5 * reference front-end implementation can be found in:
6 * drivers/net/xen-netfront.c
7 *
8 * Copyright (c) 2002-2005, K A Fraser
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License version 2
12 * as published by the Free Software Foundation; or, when distributed
13 * separately from the Linux kernel or incorporated into other
14 * software packages, subject to the following license:
15 *
16 * Permission is hereby granted, free of charge, to any person obtaining a copy
17 * of this source file (the "Software"), to deal in the Software without
18 * restriction, including without limitation the rights to use, copy, modify,
19 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
20 * and to permit persons to whom the Software is furnished to do so, subject to
21 * the following conditions:
22 *
23 * The above copyright notice and this permission notice shall be included in
24 * all copies or substantial portions of the Software.
25 *
26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
28 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
29 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
30 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
31 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
32 * IN THE SOFTWARE.
33 */
34
35#include "common.h"
36
37#include <linux/kthread.h>
38#include <linux/if_vlan.h>
39#include <linux/udp.h>
40
41#include <net/tcp.h>
42
43#include <xen/events.h>
44#include <xen/interface/memory.h>
45
46#include <asm/xen/hypercall.h>
47#include <asm/xen/page.h>
48
49struct pending_tx_info {
50 struct xen_netif_tx_request req;
51 struct xenvif *vif;
52};
53typedef unsigned int pending_ring_idx_t;
54
55struct netbk_rx_meta {
56 int id;
57 int size;
58 int gso_size;
59};
60
61#define MAX_PENDING_REQS 256
62
63#define MAX_BUFFER_OFFSET PAGE_SIZE
64
65/* extra field used in struct page */
66union page_ext {
67 struct {
68#if BITS_PER_LONG < 64
69#define IDX_WIDTH 8
70#define GROUP_WIDTH (BITS_PER_LONG - IDX_WIDTH)
71 unsigned int group:GROUP_WIDTH;
72 unsigned int idx:IDX_WIDTH;
73#else
74 unsigned int group, idx;
75#endif
76 } e;
77 void *mapping;
78};
79
80struct xen_netbk {
81 wait_queue_head_t wq;
82 struct task_struct *task;
83
84 struct sk_buff_head rx_queue;
85 struct sk_buff_head tx_queue;
86
87 struct timer_list net_timer;
88
89 struct page *mmap_pages[MAX_PENDING_REQS];
90
91 pending_ring_idx_t pending_prod;
92 pending_ring_idx_t pending_cons;
93 struct list_head net_schedule_list;
94
95 /* Protect the net_schedule_list in netif. */
96 spinlock_t net_schedule_list_lock;
97
98 atomic_t netfront_count;
99
100 struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
101 struct gnttab_copy tx_copy_ops[MAX_PENDING_REQS];
102
103 u16 pending_ring[MAX_PENDING_REQS];
104
105 /*
106 * Given MAX_BUFFER_OFFSET of 4096 the worst case is that each
107 * head/fragment page uses 2 copy operations because it
108 * straddles two buffers in the frontend.
109 */
110 struct gnttab_copy grant_copy_op[2*XEN_NETIF_RX_RING_SIZE];
111 struct netbk_rx_meta meta[2*XEN_NETIF_RX_RING_SIZE];
112};
113
114static struct xen_netbk *xen_netbk;
115static int xen_netbk_group_nr;
116
117void xen_netbk_add_xenvif(struct xenvif *vif)
118{
119 int i;
120 int min_netfront_count;
121 int min_group = 0;
122 struct xen_netbk *netbk;
123
124 min_netfront_count = atomic_read(&xen_netbk[0].netfront_count);
125 for (i = 0; i < xen_netbk_group_nr; i++) {
126 int netfront_count = atomic_read(&xen_netbk[i].netfront_count);
127 if (netfront_count < min_netfront_count) {
128 min_group = i;
129 min_netfront_count = netfront_count;
130 }
131 }
132
133 netbk = &xen_netbk[min_group];
134
135 vif->netbk = netbk;
136 atomic_inc(&netbk->netfront_count);
137}
138
139void xen_netbk_remove_xenvif(struct xenvif *vif)
140{
141 struct xen_netbk *netbk = vif->netbk;
142 vif->netbk = NULL;
143 atomic_dec(&netbk->netfront_count);
144}
145
146static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx);
147static void make_tx_response(struct xenvif *vif,
148 struct xen_netif_tx_request *txp,
149 s8 st);
150static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
151 u16 id,
152 s8 st,
153 u16 offset,
154 u16 size,
155 u16 flags);
156
157static inline unsigned long idx_to_pfn(struct xen_netbk *netbk,
158 unsigned int idx)
159{
160 return page_to_pfn(netbk->mmap_pages[idx]);
161}
162
163static inline unsigned long idx_to_kaddr(struct xen_netbk *netbk,
164 unsigned int idx)
165{
166 return (unsigned long)pfn_to_kaddr(idx_to_pfn(netbk, idx));
167}
168
169/* extra field used in struct page */
170static inline void set_page_ext(struct page *pg, struct xen_netbk *netbk,
171 unsigned int idx)
172{
173 unsigned int group = netbk - xen_netbk;
174 union page_ext ext = { .e = { .group = group + 1, .idx = idx } };
175
176 BUILD_BUG_ON(sizeof(ext) > sizeof(ext.mapping));
177 pg->mapping = ext.mapping;
178}
179
180static int get_page_ext(struct page *pg,
181 unsigned int *pgroup, unsigned int *pidx)
182{
183 union page_ext ext = { .mapping = pg->mapping };
184 struct xen_netbk *netbk;
185 unsigned int group, idx;
186
187 group = ext.e.group - 1;
188
189 if (group < 0 || group >= xen_netbk_group_nr)
190 return 0;
191
192 netbk = &xen_netbk[group];
193
194 idx = ext.e.idx;
195
196 if ((idx < 0) || (idx >= MAX_PENDING_REQS))
197 return 0;
198
199 if (netbk->mmap_pages[idx] != pg)
200 return 0;
201
202 *pgroup = group;
203 *pidx = idx;
204
205 return 1;
206}
207
208/*
209 * This is the amount of packet we copy rather than map, so that the
210 * guest can't fiddle with the contents of the headers while we do
211 * packet processing on them (netfilter, routing, etc).
212 */
213#define PKT_PROT_LEN (ETH_HLEN + \
214 VLAN_HLEN + \
215 sizeof(struct iphdr) + MAX_IPOPTLEN + \
216 sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE)
217
218static inline pending_ring_idx_t pending_index(unsigned i)
219{
220 return i & (MAX_PENDING_REQS-1);
221}
222
223static inline pending_ring_idx_t nr_pending_reqs(struct xen_netbk *netbk)
224{
225 return MAX_PENDING_REQS -
226 netbk->pending_prod + netbk->pending_cons;
227}
228
229static void xen_netbk_kick_thread(struct xen_netbk *netbk)
230{
231 wake_up(&netbk->wq);
232}
233
234static int max_required_rx_slots(struct xenvif *vif)
235{
236 int max = DIV_ROUND_UP(vif->dev->mtu, PAGE_SIZE);
237
238 if (vif->can_sg || vif->gso || vif->gso_prefix)
239 max += MAX_SKB_FRAGS + 1; /* extra_info + frags */
240
241 return max;
242}
243
244int xen_netbk_rx_ring_full(struct xenvif *vif)
245{
246 RING_IDX peek = vif->rx_req_cons_peek;
247 RING_IDX needed = max_required_rx_slots(vif);
248
249 return ((vif->rx.sring->req_prod - peek) < needed) ||
250 ((vif->rx.rsp_prod_pvt + XEN_NETIF_RX_RING_SIZE - peek) < needed);
251}
252
253int xen_netbk_must_stop_queue(struct xenvif *vif)
254{
255 if (!xen_netbk_rx_ring_full(vif))
256 return 0;
257
258 vif->rx.sring->req_event = vif->rx_req_cons_peek +
259 max_required_rx_slots(vif);
260 mb(); /* request notification /then/ check the queue */
261
262 return xen_netbk_rx_ring_full(vif);
263}
264
265/*
266 * Returns true if we should start a new receive buffer instead of
267 * adding 'size' bytes to a buffer which currently contains 'offset'
268 * bytes.
269 */
270static bool start_new_rx_buffer(int offset, unsigned long size, int head)
271{
272 /* simple case: we have completely filled the current buffer. */
273 if (offset == MAX_BUFFER_OFFSET)
274 return true;
275
276 /*
277 * complex case: start a fresh buffer if the current frag
278 * would overflow the current buffer but only if:
279 * (i) this frag would fit completely in the next buffer
280 * and (ii) there is already some data in the current buffer
281 * and (iii) this is not the head buffer.
282 *
283 * Where:
284 * - (i) stops us splitting a frag into two copies
285 * unless the frag is too large for a single buffer.
286 * - (ii) stops us from leaving a buffer pointlessly empty.
287 * - (iii) stops us leaving the first buffer
288 * empty. Strictly speaking this is already covered
289 * by (ii) but is explicitly checked because
290 * netfront relies on the first buffer being
291 * non-empty and can crash otherwise.
292 *
293 * This means we will effectively linearise small
294 * frags but do not needlessly split large buffers
295 * into multiple copies tend to give large frags their
296 * own buffers as before.
297 */
298 if ((offset + size > MAX_BUFFER_OFFSET) &&
299 (size <= MAX_BUFFER_OFFSET) && offset && !head)
300 return true;
301
302 return false;
303}
304
305/*
306 * Figure out how many ring slots we're going to need to send @skb to
307 * the guest. This function is essentially a dry run of
308 * netbk_gop_frag_copy.
309 */
310unsigned int xen_netbk_count_skb_slots(struct xenvif *vif, struct sk_buff *skb)
311{
312 unsigned int count;
313 int i, copy_off;
314
315 count = DIV_ROUND_UP(
316 offset_in_page(skb->data)+skb_headlen(skb), PAGE_SIZE);
317
318 copy_off = skb_headlen(skb) % PAGE_SIZE;
319
320 if (skb_shinfo(skb)->gso_size)
321 count++;
322
323 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
324 unsigned long size = skb_shinfo(skb)->frags[i].size;
325 unsigned long bytes;
326 while (size > 0) {
327 BUG_ON(copy_off > MAX_BUFFER_OFFSET);
328
329 if (start_new_rx_buffer(copy_off, size, 0)) {
330 count++;
331 copy_off = 0;
332 }
333
334 bytes = size;
335 if (copy_off + bytes > MAX_BUFFER_OFFSET)
336 bytes = MAX_BUFFER_OFFSET - copy_off;
337
338 copy_off += bytes;
339 size -= bytes;
340 }
341 }
342 return count;
343}
344
345struct netrx_pending_operations {
346 unsigned copy_prod, copy_cons;
347 unsigned meta_prod, meta_cons;
348 struct gnttab_copy *copy;
349 struct netbk_rx_meta *meta;
350 int copy_off;
351 grant_ref_t copy_gref;
352};
353
354static struct netbk_rx_meta *get_next_rx_buffer(struct xenvif *vif,
355 struct netrx_pending_operations *npo)
356{
357 struct netbk_rx_meta *meta;
358 struct xen_netif_rx_request *req;
359
360 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
361
362 meta = npo->meta + npo->meta_prod++;
363 meta->gso_size = 0;
364 meta->size = 0;
365 meta->id = req->id;
366
367 npo->copy_off = 0;
368 npo->copy_gref = req->gref;
369
370 return meta;
371}
372
373/*
374 * Set up the grant operations for this fragment. If it's a flipping
375 * interface, we also set up the unmap request from here.
376 */
377static void netbk_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb,
378 struct netrx_pending_operations *npo,
379 struct page *page, unsigned long size,
380 unsigned long offset, int *head)
381{
382 struct gnttab_copy *copy_gop;
383 struct netbk_rx_meta *meta;
384 /*
385 * These variables a used iff get_page_ext returns true,
386 * in which case they are guaranteed to be initialized.
387 */
388 unsigned int uninitialized_var(group), uninitialized_var(idx);
389 int foreign = get_page_ext(page, &group, &idx);
390 unsigned long bytes;
391
392 /* Data must not cross a page boundary. */
393 BUG_ON(size + offset > PAGE_SIZE);
394
395 meta = npo->meta + npo->meta_prod - 1;
396
397 while (size > 0) {
398 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
399
400 if (start_new_rx_buffer(npo->copy_off, size, *head)) {
401 /*
402 * Netfront requires there to be some data in the head
403 * buffer.
404 */
405 BUG_ON(*head);
406
407 meta = get_next_rx_buffer(vif, npo);
408 }
409
410 bytes = size;
411 if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
412 bytes = MAX_BUFFER_OFFSET - npo->copy_off;
413
414 copy_gop = npo->copy + npo->copy_prod++;
415 copy_gop->flags = GNTCOPY_dest_gref;
416 if (foreign) {
417 struct xen_netbk *netbk = &xen_netbk[group];
418 struct pending_tx_info *src_pend;
419
420 src_pend = &netbk->pending_tx_info[idx];
421
422 copy_gop->source.domid = src_pend->vif->domid;
423 copy_gop->source.u.ref = src_pend->req.gref;
424 copy_gop->flags |= GNTCOPY_source_gref;
425 } else {
426 void *vaddr = page_address(page);
427 copy_gop->source.domid = DOMID_SELF;
428 copy_gop->source.u.gmfn = virt_to_mfn(vaddr);
429 }
430 copy_gop->source.offset = offset;
431 copy_gop->dest.domid = vif->domid;
432
433 copy_gop->dest.offset = npo->copy_off;
434 copy_gop->dest.u.ref = npo->copy_gref;
435 copy_gop->len = bytes;
436
437 npo->copy_off += bytes;
438 meta->size += bytes;
439
440 offset += bytes;
441 size -= bytes;
442
443 /* Leave a gap for the GSO descriptor. */
444 if (*head && skb_shinfo(skb)->gso_size && !vif->gso_prefix)
445 vif->rx.req_cons++;
446
447 *head = 0; /* There must be something in this buffer now. */
448
449 }
450}
451
452/*
453 * Prepare an SKB to be transmitted to the frontend.
454 *
455 * This function is responsible for allocating grant operations, meta
456 * structures, etc.
457 *
458 * It returns the number of meta structures consumed. The number of
459 * ring slots used is always equal to the number of meta slots used
460 * plus the number of GSO descriptors used. Currently, we use either
461 * zero GSO descriptors (for non-GSO packets) or one descriptor (for
462 * frontend-side LRO).
463 */
464static int netbk_gop_skb(struct sk_buff *skb,
465 struct netrx_pending_operations *npo)
466{
467 struct xenvif *vif = netdev_priv(skb->dev);
468 int nr_frags = skb_shinfo(skb)->nr_frags;
469 int i;
470 struct xen_netif_rx_request *req;
471 struct netbk_rx_meta *meta;
472 unsigned char *data;
473 int head = 1;
474 int old_meta_prod;
475
476 old_meta_prod = npo->meta_prod;
477
478 /* Set up a GSO prefix descriptor, if necessary */
479 if (skb_shinfo(skb)->gso_size && vif->gso_prefix) {
480 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
481 meta = npo->meta + npo->meta_prod++;
482 meta->gso_size = skb_shinfo(skb)->gso_size;
483 meta->size = 0;
484 meta->id = req->id;
485 }
486
487 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
488 meta = npo->meta + npo->meta_prod++;
489
490 if (!vif->gso_prefix)
491 meta->gso_size = skb_shinfo(skb)->gso_size;
492 else
493 meta->gso_size = 0;
494
495 meta->size = 0;
496 meta->id = req->id;
497 npo->copy_off = 0;
498 npo->copy_gref = req->gref;
499
500 data = skb->data;
501 while (data < skb_tail_pointer(skb)) {
502 unsigned int offset = offset_in_page(data);
503 unsigned int len = PAGE_SIZE - offset;
504
505 if (data + len > skb_tail_pointer(skb))
506 len = skb_tail_pointer(skb) - data;
507
508 netbk_gop_frag_copy(vif, skb, npo,
509 virt_to_page(data), len, offset, &head);
510 data += len;
511 }
512
513 for (i = 0; i < nr_frags; i++) {
514 netbk_gop_frag_copy(vif, skb, npo,
515 skb_shinfo(skb)->frags[i].page,
516 skb_shinfo(skb)->frags[i].size,
517 skb_shinfo(skb)->frags[i].page_offset,
518 &head);
519 }
520
521 return npo->meta_prod - old_meta_prod;
522}
523
524/*
525 * This is a twin to netbk_gop_skb. Assume that netbk_gop_skb was
526 * used to set up the operations on the top of
527 * netrx_pending_operations, which have since been done. Check that
528 * they didn't give any errors and advance over them.
529 */
530static int netbk_check_gop(struct xenvif *vif, int nr_meta_slots,
531 struct netrx_pending_operations *npo)
532{
533 struct gnttab_copy *copy_op;
534 int status = XEN_NETIF_RSP_OKAY;
535 int i;
536
537 for (i = 0; i < nr_meta_slots; i++) {
538 copy_op = npo->copy + npo->copy_cons++;
539 if (copy_op->status != GNTST_okay) {
540 netdev_dbg(vif->dev,
541 "Bad status %d from copy to DOM%d.\n",
542 copy_op->status, vif->domid);
543 status = XEN_NETIF_RSP_ERROR;
544 }
545 }
546
547 return status;
548}
549
550static void netbk_add_frag_responses(struct xenvif *vif, int status,
551 struct netbk_rx_meta *meta,
552 int nr_meta_slots)
553{
554 int i;
555 unsigned long offset;
556
557 /* No fragments used */
558 if (nr_meta_slots <= 1)
559 return;
560
561 nr_meta_slots--;
562
563 for (i = 0; i < nr_meta_slots; i++) {
564 int flags;
565 if (i == nr_meta_slots - 1)
566 flags = 0;
567 else
568 flags = XEN_NETRXF_more_data;
569
570 offset = 0;
571 make_rx_response(vif, meta[i].id, status, offset,
572 meta[i].size, flags);
573 }
574}
575
576struct skb_cb_overlay {
577 int meta_slots_used;
578};
579
580static void xen_netbk_rx_action(struct xen_netbk *netbk)
581{
582 struct xenvif *vif = NULL, *tmp;
583 s8 status;
584 u16 irq, flags;
585 struct xen_netif_rx_response *resp;
586 struct sk_buff_head rxq;
587 struct sk_buff *skb;
588 LIST_HEAD(notify);
589 int ret;
590 int nr_frags;
591 int count;
592 unsigned long offset;
593 struct skb_cb_overlay *sco;
594
595 struct netrx_pending_operations npo = {
596 .copy = netbk->grant_copy_op,
597 .meta = netbk->meta,
598 };
599
600 skb_queue_head_init(&rxq);
601
602 count = 0;
603
604 while ((skb = skb_dequeue(&netbk->rx_queue)) != NULL) {
605 vif = netdev_priv(skb->dev);
606 nr_frags = skb_shinfo(skb)->nr_frags;
607
608 sco = (struct skb_cb_overlay *)skb->cb;
609 sco->meta_slots_used = netbk_gop_skb(skb, &npo);
610
611 count += nr_frags + 1;
612
613 __skb_queue_tail(&rxq, skb);
614
615 /* Filled the batch queue? */
616 if (count + MAX_SKB_FRAGS >= XEN_NETIF_RX_RING_SIZE)
617 break;
618 }
619
620 BUG_ON(npo.meta_prod > ARRAY_SIZE(netbk->meta));
621
622 if (!npo.copy_prod)
623 return;
624
625 BUG_ON(npo.copy_prod > ARRAY_SIZE(netbk->grant_copy_op));
626 ret = HYPERVISOR_grant_table_op(GNTTABOP_copy, &netbk->grant_copy_op,
627 npo.copy_prod);
628 BUG_ON(ret != 0);
629
630 while ((skb = __skb_dequeue(&rxq)) != NULL) {
631 sco = (struct skb_cb_overlay *)skb->cb;
632
633 vif = netdev_priv(skb->dev);
634
635 if (netbk->meta[npo.meta_cons].gso_size && vif->gso_prefix) {
636 resp = RING_GET_RESPONSE(&vif->rx,
637 vif->rx.rsp_prod_pvt++);
638
639 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
640
641 resp->offset = netbk->meta[npo.meta_cons].gso_size;
642 resp->id = netbk->meta[npo.meta_cons].id;
643 resp->status = sco->meta_slots_used;
644
645 npo.meta_cons++;
646 sco->meta_slots_used--;
647 }
648
649
650 vif->dev->stats.tx_bytes += skb->len;
651 vif->dev->stats.tx_packets++;
652
653 status = netbk_check_gop(vif, sco->meta_slots_used, &npo);
654
655 if (sco->meta_slots_used == 1)
656 flags = 0;
657 else
658 flags = XEN_NETRXF_more_data;
659
660 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
661 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
662 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
663 /* remote but checksummed. */
664 flags |= XEN_NETRXF_data_validated;
665
666 offset = 0;
667 resp = make_rx_response(vif, netbk->meta[npo.meta_cons].id,
668 status, offset,
669 netbk->meta[npo.meta_cons].size,
670 flags);
671
672 if (netbk->meta[npo.meta_cons].gso_size && !vif->gso_prefix) {
673 struct xen_netif_extra_info *gso =
674 (struct xen_netif_extra_info *)
675 RING_GET_RESPONSE(&vif->rx,
676 vif->rx.rsp_prod_pvt++);
677
678 resp->flags |= XEN_NETRXF_extra_info;
679
680 gso->u.gso.size = netbk->meta[npo.meta_cons].gso_size;
681 gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
682 gso->u.gso.pad = 0;
683 gso->u.gso.features = 0;
684
685 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
686 gso->flags = 0;
687 }
688
689 netbk_add_frag_responses(vif, status,
690 netbk->meta + npo.meta_cons + 1,
691 sco->meta_slots_used);
692
693 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret);
694 irq = vif->irq;
695 if (ret && list_empty(&vif->notify_list))
696 list_add_tail(&vif->notify_list, ¬ify);
697
698 xenvif_notify_tx_completion(vif);
699
700 xenvif_put(vif);
701 npo.meta_cons += sco->meta_slots_used;
702 dev_kfree_skb(skb);
703 }
704
705 list_for_each_entry_safe(vif, tmp, ¬ify, notify_list) {
706 notify_remote_via_irq(vif->irq);
707 list_del_init(&vif->notify_list);
708 }
709
710 /* More work to do? */
711 if (!skb_queue_empty(&netbk->rx_queue) &&
712 !timer_pending(&netbk->net_timer))
713 xen_netbk_kick_thread(netbk);
714}
715
716void xen_netbk_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb)
717{
718 struct xen_netbk *netbk = vif->netbk;
719
720 skb_queue_tail(&netbk->rx_queue, skb);
721
722 xen_netbk_kick_thread(netbk);
723}
724
725static void xen_netbk_alarm(unsigned long data)
726{
727 struct xen_netbk *netbk = (struct xen_netbk *)data;
728 xen_netbk_kick_thread(netbk);
729}
730
731static int __on_net_schedule_list(struct xenvif *vif)
732{
733 return !list_empty(&vif->schedule_list);
734}
735
736/* Must be called with net_schedule_list_lock held */
737static void remove_from_net_schedule_list(struct xenvif *vif)
738{
739 if (likely(__on_net_schedule_list(vif))) {
740 list_del_init(&vif->schedule_list);
741 xenvif_put(vif);
742 }
743}
744
745static struct xenvif *poll_net_schedule_list(struct xen_netbk *netbk)
746{
747 struct xenvif *vif = NULL;
748
749 spin_lock_irq(&netbk->net_schedule_list_lock);
750 if (list_empty(&netbk->net_schedule_list))
751 goto out;
752
753 vif = list_first_entry(&netbk->net_schedule_list,
754 struct xenvif, schedule_list);
755 if (!vif)
756 goto out;
757
758 xenvif_get(vif);
759
760 remove_from_net_schedule_list(vif);
761out:
762 spin_unlock_irq(&netbk->net_schedule_list_lock);
763 return vif;
764}
765
766void xen_netbk_schedule_xenvif(struct xenvif *vif)
767{
768 unsigned long flags;
769 struct xen_netbk *netbk = vif->netbk;
770
771 if (__on_net_schedule_list(vif))
772 goto kick;
773
774 spin_lock_irqsave(&netbk->net_schedule_list_lock, flags);
775 if (!__on_net_schedule_list(vif) &&
776 likely(xenvif_schedulable(vif))) {
777 list_add_tail(&vif->schedule_list, &netbk->net_schedule_list);
778 xenvif_get(vif);
779 }
780 spin_unlock_irqrestore(&netbk->net_schedule_list_lock, flags);
781
782kick:
783 smp_mb();
784 if ((nr_pending_reqs(netbk) < (MAX_PENDING_REQS/2)) &&
785 !list_empty(&netbk->net_schedule_list))
786 xen_netbk_kick_thread(netbk);
787}
788
789void xen_netbk_deschedule_xenvif(struct xenvif *vif)
790{
791 struct xen_netbk *netbk = vif->netbk;
792 spin_lock_irq(&netbk->net_schedule_list_lock);
793 remove_from_net_schedule_list(vif);
794 spin_unlock_irq(&netbk->net_schedule_list_lock);
795}
796
797void xen_netbk_check_rx_xenvif(struct xenvif *vif)
798{
799 int more_to_do;
800
801 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
802
803 if (more_to_do)
804 xen_netbk_schedule_xenvif(vif);
805}
806
807static void tx_add_credit(struct xenvif *vif)
808{
809 unsigned long max_burst, max_credit;
810
811 /*
812 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
813 * Otherwise the interface can seize up due to insufficient credit.
814 */
815 max_burst = RING_GET_REQUEST(&vif->tx, vif->tx.req_cons)->size;
816 max_burst = min(max_burst, 131072UL);
817 max_burst = max(max_burst, vif->credit_bytes);
818
819 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
820 max_credit = vif->remaining_credit + vif->credit_bytes;
821 if (max_credit < vif->remaining_credit)
822 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
823
824 vif->remaining_credit = min(max_credit, max_burst);
825}
826
827static void tx_credit_callback(unsigned long data)
828{
829 struct xenvif *vif = (struct xenvif *)data;
830 tx_add_credit(vif);
831 xen_netbk_check_rx_xenvif(vif);
832}
833
834static void netbk_tx_err(struct xenvif *vif,
835 struct xen_netif_tx_request *txp, RING_IDX end)
836{
837 RING_IDX cons = vif->tx.req_cons;
838
839 do {
840 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
841 if (cons >= end)
842 break;
843 txp = RING_GET_REQUEST(&vif->tx, cons++);
844 } while (1);
845 vif->tx.req_cons = cons;
846 xen_netbk_check_rx_xenvif(vif);
847 xenvif_put(vif);
848}
849
850static int netbk_count_requests(struct xenvif *vif,
851 struct xen_netif_tx_request *first,
852 struct xen_netif_tx_request *txp,
853 int work_to_do)
854{
855 RING_IDX cons = vif->tx.req_cons;
856 int frags = 0;
857
858 if (!(first->flags & XEN_NETTXF_more_data))
859 return 0;
860
861 do {
862 if (frags >= work_to_do) {
863 netdev_dbg(vif->dev, "Need more frags\n");
864 return -frags;
865 }
866
867 if (unlikely(frags >= MAX_SKB_FRAGS)) {
868 netdev_dbg(vif->dev, "Too many frags\n");
869 return -frags;
870 }
871
872 memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + frags),
873 sizeof(*txp));
874 if (txp->size > first->size) {
875 netdev_dbg(vif->dev, "Frags galore\n");
876 return -frags;
877 }
878
879 first->size -= txp->size;
880 frags++;
881
882 if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
883 netdev_dbg(vif->dev, "txp->offset: %x, size: %u\n",
884 txp->offset, txp->size);
885 return -frags;
886 }
887 } while ((txp++)->flags & XEN_NETTXF_more_data);
888 return frags;
889}
890
891static struct page *xen_netbk_alloc_page(struct xen_netbk *netbk,
892 struct sk_buff *skb,
893 unsigned long pending_idx)
894{
895 struct page *page;
896 page = alloc_page(GFP_KERNEL|__GFP_COLD);
897 if (!page)
898 return NULL;
899 set_page_ext(page, netbk, pending_idx);
900 netbk->mmap_pages[pending_idx] = page;
901 return page;
902}
903
904static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
905 struct xenvif *vif,
906 struct sk_buff *skb,
907 struct xen_netif_tx_request *txp,
908 struct gnttab_copy *gop)
909{
910 struct skb_shared_info *shinfo = skb_shinfo(skb);
911 skb_frag_t *frags = shinfo->frags;
912 unsigned long pending_idx = *((u16 *)skb->data);
913 int i, start;
914
915 /* Skip first skb fragment if it is on same page as header fragment. */
916 start = ((unsigned long)shinfo->frags[0].page == pending_idx);
917
918 for (i = start; i < shinfo->nr_frags; i++, txp++) {
919 struct page *page;
920 pending_ring_idx_t index;
921 struct pending_tx_info *pending_tx_info =
922 netbk->pending_tx_info;
923
924 index = pending_index(netbk->pending_cons++);
925 pending_idx = netbk->pending_ring[index];
926 page = xen_netbk_alloc_page(netbk, skb, pending_idx);
927 if (!page)
928 return NULL;
929
930 netbk->mmap_pages[pending_idx] = page;
931
932 gop->source.u.ref = txp->gref;
933 gop->source.domid = vif->domid;
934 gop->source.offset = txp->offset;
935
936 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
937 gop->dest.domid = DOMID_SELF;
938 gop->dest.offset = txp->offset;
939
940 gop->len = txp->size;
941 gop->flags = GNTCOPY_source_gref;
942
943 gop++;
944
945 memcpy(&pending_tx_info[pending_idx].req, txp, sizeof(*txp));
946 xenvif_get(vif);
947 pending_tx_info[pending_idx].vif = vif;
948 frags[i].page = (void *)pending_idx;
949 }
950
951 return gop;
952}
953
954static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
955 struct sk_buff *skb,
956 struct gnttab_copy **gopp)
957{
958 struct gnttab_copy *gop = *gopp;
959 int pending_idx = *((u16 *)skb->data);
960 struct pending_tx_info *pending_tx_info = netbk->pending_tx_info;
961 struct xenvif *vif = pending_tx_info[pending_idx].vif;
962 struct xen_netif_tx_request *txp;
963 struct skb_shared_info *shinfo = skb_shinfo(skb);
964 int nr_frags = shinfo->nr_frags;
965 int i, err, start;
966
967 /* Check status of header. */
968 err = gop->status;
969 if (unlikely(err)) {
970 pending_ring_idx_t index;
971 index = pending_index(netbk->pending_prod++);
972 txp = &pending_tx_info[pending_idx].req;
973 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
974 netbk->pending_ring[index] = pending_idx;
975 xenvif_put(vif);
976 }
977
978 /* Skip first skb fragment if it is on same page as header fragment. */
979 start = ((unsigned long)shinfo->frags[0].page == pending_idx);
980
981 for (i = start; i < nr_frags; i++) {
982 int j, newerr;
983 pending_ring_idx_t index;
984
985 pending_idx = (unsigned long)shinfo->frags[i].page;
986
987 /* Check error status: if okay then remember grant handle. */
988 newerr = (++gop)->status;
989 if (likely(!newerr)) {
990 /* Had a previous error? Invalidate this fragment. */
991 if (unlikely(err))
992 xen_netbk_idx_release(netbk, pending_idx);
993 continue;
994 }
995
996 /* Error on this fragment: respond to client with an error. */
997 txp = &netbk->pending_tx_info[pending_idx].req;
998 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
999 index = pending_index(netbk->pending_prod++);
1000 netbk->pending_ring[index] = pending_idx;
1001 xenvif_put(vif);
1002
1003 /* Not the first error? Preceding frags already invalidated. */
1004 if (err)
1005 continue;
1006
1007 /* First error: invalidate header and preceding fragments. */
1008 pending_idx = *((u16 *)skb->data);
1009 xen_netbk_idx_release(netbk, pending_idx);
1010 for (j = start; j < i; j++) {
1011 pending_idx = (unsigned long)shinfo->frags[i].page;
1012 xen_netbk_idx_release(netbk, pending_idx);
1013 }
1014
1015 /* Remember the error: invalidate all subsequent fragments. */
1016 err = newerr;
1017 }
1018
1019 *gopp = gop + 1;
1020 return err;
1021}
1022
1023static void xen_netbk_fill_frags(struct xen_netbk *netbk, struct sk_buff *skb)
1024{
1025 struct skb_shared_info *shinfo = skb_shinfo(skb);
1026 int nr_frags = shinfo->nr_frags;
1027 int i;
1028
1029 for (i = 0; i < nr_frags; i++) {
1030 skb_frag_t *frag = shinfo->frags + i;
1031 struct xen_netif_tx_request *txp;
1032 unsigned long pending_idx;
1033
1034 pending_idx = (unsigned long)frag->page;
1035
1036 txp = &netbk->pending_tx_info[pending_idx].req;
1037 frag->page = virt_to_page(idx_to_kaddr(netbk, pending_idx));
1038 frag->size = txp->size;
1039 frag->page_offset = txp->offset;
1040
1041 skb->len += txp->size;
1042 skb->data_len += txp->size;
1043 skb->truesize += txp->size;
1044
1045 /* Take an extra reference to offset xen_netbk_idx_release */
1046 get_page(netbk->mmap_pages[pending_idx]);
1047 xen_netbk_idx_release(netbk, pending_idx);
1048 }
1049}
1050
1051static int xen_netbk_get_extras(struct xenvif *vif,
1052 struct xen_netif_extra_info *extras,
1053 int work_to_do)
1054{
1055 struct xen_netif_extra_info extra;
1056 RING_IDX cons = vif->tx.req_cons;
1057
1058 do {
1059 if (unlikely(work_to_do-- <= 0)) {
1060 netdev_dbg(vif->dev, "Missing extra info\n");
1061 return -EBADR;
1062 }
1063
1064 memcpy(&extra, RING_GET_REQUEST(&vif->tx, cons),
1065 sizeof(extra));
1066 if (unlikely(!extra.type ||
1067 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1068 vif->tx.req_cons = ++cons;
1069 netdev_dbg(vif->dev,
1070 "Invalid extra type: %d\n", extra.type);
1071 return -EINVAL;
1072 }
1073
1074 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1075 vif->tx.req_cons = ++cons;
1076 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1077
1078 return work_to_do;
1079}
1080
1081static int netbk_set_skb_gso(struct xenvif *vif,
1082 struct sk_buff *skb,
1083 struct xen_netif_extra_info *gso)
1084{
1085 if (!gso->u.gso.size) {
1086 netdev_dbg(vif->dev, "GSO size must not be zero.\n");
1087 return -EINVAL;
1088 }
1089
1090 /* Currently only TCPv4 S.O. is supported. */
1091 if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
1092 netdev_dbg(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1093 return -EINVAL;
1094 }
1095
1096 skb_shinfo(skb)->gso_size = gso->u.gso.size;
1097 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1098
1099 /* Header must be checked, and gso_segs computed. */
1100 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1101 skb_shinfo(skb)->gso_segs = 0;
1102
1103 return 0;
1104}
1105
1106static int checksum_setup(struct xenvif *vif, struct sk_buff *skb)
1107{
1108 struct iphdr *iph;
1109 unsigned char *th;
1110 int err = -EPROTO;
1111 int recalculate_partial_csum = 0;
1112
1113 /*
1114 * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1115 * peers can fail to set NETRXF_csum_blank when sending a GSO
1116 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1117 * recalculate the partial checksum.
1118 */
1119 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1120 vif->rx_gso_checksum_fixup++;
1121 skb->ip_summed = CHECKSUM_PARTIAL;
1122 recalculate_partial_csum = 1;
1123 }
1124
1125 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1126 if (skb->ip_summed != CHECKSUM_PARTIAL)
1127 return 0;
1128
1129 if (skb->protocol != htons(ETH_P_IP))
1130 goto out;
1131
1132 iph = (void *)skb->data;
1133 th = skb->data + 4 * iph->ihl;
1134 if (th >= skb_tail_pointer(skb))
1135 goto out;
1136
1137 skb->csum_start = th - skb->head;
1138 switch (iph->protocol) {
1139 case IPPROTO_TCP:
1140 skb->csum_offset = offsetof(struct tcphdr, check);
1141
1142 if (recalculate_partial_csum) {
1143 struct tcphdr *tcph = (struct tcphdr *)th;
1144 tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1145 skb->len - iph->ihl*4,
1146 IPPROTO_TCP, 0);
1147 }
1148 break;
1149 case IPPROTO_UDP:
1150 skb->csum_offset = offsetof(struct udphdr, check);
1151
1152 if (recalculate_partial_csum) {
1153 struct udphdr *udph = (struct udphdr *)th;
1154 udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1155 skb->len - iph->ihl*4,
1156 IPPROTO_UDP, 0);
1157 }
1158 break;
1159 default:
1160 if (net_ratelimit())
1161 netdev_err(vif->dev,
1162 "Attempting to checksum a non-TCP/UDP packet, dropping a protocol %d packet\n",
1163 iph->protocol);
1164 goto out;
1165 }
1166
1167 if ((th + skb->csum_offset + 2) > skb_tail_pointer(skb))
1168 goto out;
1169
1170 err = 0;
1171
1172out:
1173 return err;
1174}
1175
1176static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
1177{
1178 unsigned long now = jiffies;
1179 unsigned long next_credit =
1180 vif->credit_timeout.expires +
1181 msecs_to_jiffies(vif->credit_usec / 1000);
1182
1183 /* Timer could already be pending in rare cases. */
1184 if (timer_pending(&vif->credit_timeout))
1185 return true;
1186
1187 /* Passed the point where we can replenish credit? */
1188 if (time_after_eq(now, next_credit)) {
1189 vif->credit_timeout.expires = now;
1190 tx_add_credit(vif);
1191 }
1192
1193 /* Still too big to send right now? Set a callback. */
1194 if (size > vif->remaining_credit) {
1195 vif->credit_timeout.data =
1196 (unsigned long)vif;
1197 vif->credit_timeout.function =
1198 tx_credit_callback;
1199 mod_timer(&vif->credit_timeout,
1200 next_credit);
1201
1202 return true;
1203 }
1204
1205 return false;
1206}
1207
1208static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk)
1209{
1210 struct gnttab_copy *gop = netbk->tx_copy_ops, *request_gop;
1211 struct sk_buff *skb;
1212 int ret;
1213
1214 while (((nr_pending_reqs(netbk) + MAX_SKB_FRAGS) < MAX_PENDING_REQS) &&
1215 !list_empty(&netbk->net_schedule_list)) {
1216 struct xenvif *vif;
1217 struct xen_netif_tx_request txreq;
1218 struct xen_netif_tx_request txfrags[MAX_SKB_FRAGS];
1219 struct page *page;
1220 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
1221 u16 pending_idx;
1222 RING_IDX idx;
1223 int work_to_do;
1224 unsigned int data_len;
1225 pending_ring_idx_t index;
1226
1227 /* Get a netif from the list with work to do. */
1228 vif = poll_net_schedule_list(netbk);
1229 if (!vif)
1230 continue;
1231
1232 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, work_to_do);
1233 if (!work_to_do) {
1234 xenvif_put(vif);
1235 continue;
1236 }
1237
1238 idx = vif->tx.req_cons;
1239 rmb(); /* Ensure that we see the request before we copy it. */
1240 memcpy(&txreq, RING_GET_REQUEST(&vif->tx, idx), sizeof(txreq));
1241
1242 /* Credit-based scheduling. */
1243 if (txreq.size > vif->remaining_credit &&
1244 tx_credit_exceeded(vif, txreq.size)) {
1245 xenvif_put(vif);
1246 continue;
1247 }
1248
1249 vif->remaining_credit -= txreq.size;
1250
1251 work_to_do--;
1252 vif->tx.req_cons = ++idx;
1253
1254 memset(extras, 0, sizeof(extras));
1255 if (txreq.flags & XEN_NETTXF_extra_info) {
1256 work_to_do = xen_netbk_get_extras(vif, extras,
1257 work_to_do);
1258 idx = vif->tx.req_cons;
1259 if (unlikely(work_to_do < 0)) {
1260 netbk_tx_err(vif, &txreq, idx);
1261 continue;
1262 }
1263 }
1264
1265 ret = netbk_count_requests(vif, &txreq, txfrags, work_to_do);
1266 if (unlikely(ret < 0)) {
1267 netbk_tx_err(vif, &txreq, idx - ret);
1268 continue;
1269 }
1270 idx += ret;
1271
1272 if (unlikely(txreq.size < ETH_HLEN)) {
1273 netdev_dbg(vif->dev,
1274 "Bad packet size: %d\n", txreq.size);
1275 netbk_tx_err(vif, &txreq, idx);
1276 continue;
1277 }
1278
1279 /* No crossing a page as the payload mustn't fragment. */
1280 if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
1281 netdev_dbg(vif->dev,
1282 "txreq.offset: %x, size: %u, end: %lu\n",
1283 txreq.offset, txreq.size,
1284 (txreq.offset&~PAGE_MASK) + txreq.size);
1285 netbk_tx_err(vif, &txreq, idx);
1286 continue;
1287 }
1288
1289 index = pending_index(netbk->pending_cons);
1290 pending_idx = netbk->pending_ring[index];
1291
1292 data_len = (txreq.size > PKT_PROT_LEN &&
1293 ret < MAX_SKB_FRAGS) ?
1294 PKT_PROT_LEN : txreq.size;
1295
1296 skb = alloc_skb(data_len + NET_SKB_PAD + NET_IP_ALIGN,
1297 GFP_ATOMIC | __GFP_NOWARN);
1298 if (unlikely(skb == NULL)) {
1299 netdev_dbg(vif->dev,
1300 "Can't allocate a skb in start_xmit.\n");
1301 netbk_tx_err(vif, &txreq, idx);
1302 break;
1303 }
1304
1305 /* Packets passed to netif_rx() must have some headroom. */
1306 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
1307
1308 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1309 struct xen_netif_extra_info *gso;
1310 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1311
1312 if (netbk_set_skb_gso(vif, skb, gso)) {
1313 kfree_skb(skb);
1314 netbk_tx_err(vif, &txreq, idx);
1315 continue;
1316 }
1317 }
1318
1319 /* XXX could copy straight to head */
1320 page = xen_netbk_alloc_page(netbk, skb, pending_idx);
1321 if (!page) {
1322 kfree_skb(skb);
1323 netbk_tx_err(vif, &txreq, idx);
1324 continue;
1325 }
1326
1327 netbk->mmap_pages[pending_idx] = page;
1328
1329 gop->source.u.ref = txreq.gref;
1330 gop->source.domid = vif->domid;
1331 gop->source.offset = txreq.offset;
1332
1333 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
1334 gop->dest.domid = DOMID_SELF;
1335 gop->dest.offset = txreq.offset;
1336
1337 gop->len = txreq.size;
1338 gop->flags = GNTCOPY_source_gref;
1339
1340 gop++;
1341
1342 memcpy(&netbk->pending_tx_info[pending_idx].req,
1343 &txreq, sizeof(txreq));
1344 netbk->pending_tx_info[pending_idx].vif = vif;
1345 *((u16 *)skb->data) = pending_idx;
1346
1347 __skb_put(skb, data_len);
1348
1349 skb_shinfo(skb)->nr_frags = ret;
1350 if (data_len < txreq.size) {
1351 skb_shinfo(skb)->nr_frags++;
1352 skb_shinfo(skb)->frags[0].page =
1353 (void *)(unsigned long)pending_idx;
1354 } else {
1355 /* Discriminate from any valid pending_idx value. */
1356 skb_shinfo(skb)->frags[0].page = (void *)~0UL;
1357 }
1358
1359 __skb_queue_tail(&netbk->tx_queue, skb);
1360
1361 netbk->pending_cons++;
1362
1363 request_gop = xen_netbk_get_requests(netbk, vif,
1364 skb, txfrags, gop);
1365 if (request_gop == NULL) {
1366 kfree_skb(skb);
1367 netbk_tx_err(vif, &txreq, idx);
1368 continue;
1369 }
1370 gop = request_gop;
1371
1372 vif->tx.req_cons = idx;
1373 xen_netbk_check_rx_xenvif(vif);
1374
1375 if ((gop-netbk->tx_copy_ops) >= ARRAY_SIZE(netbk->tx_copy_ops))
1376 break;
1377 }
1378
1379 return gop - netbk->tx_copy_ops;
1380}
1381
1382static void xen_netbk_tx_submit(struct xen_netbk *netbk)
1383{
1384 struct gnttab_copy *gop = netbk->tx_copy_ops;
1385 struct sk_buff *skb;
1386
1387 while ((skb = __skb_dequeue(&netbk->tx_queue)) != NULL) {
1388 struct xen_netif_tx_request *txp;
1389 struct xenvif *vif;
1390 u16 pending_idx;
1391 unsigned data_len;
1392
1393 pending_idx = *((u16 *)skb->data);
1394 vif = netbk->pending_tx_info[pending_idx].vif;
1395 txp = &netbk->pending_tx_info[pending_idx].req;
1396
1397 /* Check the remap error code. */
1398 if (unlikely(xen_netbk_tx_check_gop(netbk, skb, &gop))) {
1399 netdev_dbg(vif->dev, "netback grant failed.\n");
1400 skb_shinfo(skb)->nr_frags = 0;
1401 kfree_skb(skb);
1402 continue;
1403 }
1404
1405 data_len = skb->len;
1406 memcpy(skb->data,
1407 (void *)(idx_to_kaddr(netbk, pending_idx)|txp->offset),
1408 data_len);
1409 if (data_len < txp->size) {
1410 /* Append the packet payload as a fragment. */
1411 txp->offset += data_len;
1412 txp->size -= data_len;
1413 } else {
1414 /* Schedule a response immediately. */
1415 xen_netbk_idx_release(netbk, pending_idx);
1416 }
1417
1418 if (txp->flags & XEN_NETTXF_csum_blank)
1419 skb->ip_summed = CHECKSUM_PARTIAL;
1420 else if (txp->flags & XEN_NETTXF_data_validated)
1421 skb->ip_summed = CHECKSUM_UNNECESSARY;
1422
1423 xen_netbk_fill_frags(netbk, skb);
1424
1425 /*
1426 * If the initial fragment was < PKT_PROT_LEN then
1427 * pull through some bytes from the other fragments to
1428 * increase the linear region to PKT_PROT_LEN bytes.
1429 */
1430 if (skb_headlen(skb) < PKT_PROT_LEN && skb_is_nonlinear(skb)) {
1431 int target = min_t(int, skb->len, PKT_PROT_LEN);
1432 __pskb_pull_tail(skb, target - skb_headlen(skb));
1433 }
1434
1435 skb->dev = vif->dev;
1436 skb->protocol = eth_type_trans(skb, skb->dev);
1437
1438 if (checksum_setup(vif, skb)) {
1439 netdev_dbg(vif->dev,
1440 "Can't setup checksum in net_tx_action\n");
1441 kfree_skb(skb);
1442 continue;
1443 }
1444
1445 vif->dev->stats.rx_bytes += skb->len;
1446 vif->dev->stats.rx_packets++;
1447
1448 xenvif_receive_skb(vif, skb);
1449 }
1450}
1451
1452/* Called after netfront has transmitted */
1453static void xen_netbk_tx_action(struct xen_netbk *netbk)
1454{
1455 unsigned nr_gops;
1456 int ret;
1457
1458 nr_gops = xen_netbk_tx_build_gops(netbk);
1459
1460 if (nr_gops == 0)
1461 return;
1462 ret = HYPERVISOR_grant_table_op(GNTTABOP_copy,
1463 netbk->tx_copy_ops, nr_gops);
1464 BUG_ON(ret);
1465
1466 xen_netbk_tx_submit(netbk);
1467
1468}
1469
1470static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx)
1471{
1472 struct xenvif *vif;
1473 struct pending_tx_info *pending_tx_info;
1474 pending_ring_idx_t index;
1475
1476 /* Already complete? */
1477 if (netbk->mmap_pages[pending_idx] == NULL)
1478 return;
1479
1480 pending_tx_info = &netbk->pending_tx_info[pending_idx];
1481
1482 vif = pending_tx_info->vif;
1483
1484 make_tx_response(vif, &pending_tx_info->req, XEN_NETIF_RSP_OKAY);
1485
1486 index = pending_index(netbk->pending_prod++);
1487 netbk->pending_ring[index] = pending_idx;
1488
1489 xenvif_put(vif);
1490
1491 netbk->mmap_pages[pending_idx]->mapping = 0;
1492 put_page(netbk->mmap_pages[pending_idx]);
1493 netbk->mmap_pages[pending_idx] = NULL;
1494}
1495
1496static void make_tx_response(struct xenvif *vif,
1497 struct xen_netif_tx_request *txp,
1498 s8 st)
1499{
1500 RING_IDX i = vif->tx.rsp_prod_pvt;
1501 struct xen_netif_tx_response *resp;
1502 int notify;
1503
1504 resp = RING_GET_RESPONSE(&vif->tx, i);
1505 resp->id = txp->id;
1506 resp->status = st;
1507
1508 if (txp->flags & XEN_NETTXF_extra_info)
1509 RING_GET_RESPONSE(&vif->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1510
1511 vif->tx.rsp_prod_pvt = ++i;
1512 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->tx, notify);
1513 if (notify)
1514 notify_remote_via_irq(vif->irq);
1515}
1516
1517static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
1518 u16 id,
1519 s8 st,
1520 u16 offset,
1521 u16 size,
1522 u16 flags)
1523{
1524 RING_IDX i = vif->rx.rsp_prod_pvt;
1525 struct xen_netif_rx_response *resp;
1526
1527 resp = RING_GET_RESPONSE(&vif->rx, i);
1528 resp->offset = offset;
1529 resp->flags = flags;
1530 resp->id = id;
1531 resp->status = (s16)size;
1532 if (st < 0)
1533 resp->status = (s16)st;
1534
1535 vif->rx.rsp_prod_pvt = ++i;
1536
1537 return resp;
1538}
1539
1540static inline int rx_work_todo(struct xen_netbk *netbk)
1541{
1542 return !skb_queue_empty(&netbk->rx_queue);
1543}
1544
1545static inline int tx_work_todo(struct xen_netbk *netbk)
1546{
1547
1548 if (((nr_pending_reqs(netbk) + MAX_SKB_FRAGS) < MAX_PENDING_REQS) &&
1549 !list_empty(&netbk->net_schedule_list))
1550 return 1;
1551
1552 return 0;
1553}
1554
1555static int xen_netbk_kthread(void *data)
1556{
1557 struct xen_netbk *netbk = data;
1558 while (!kthread_should_stop()) {
1559 wait_event_interruptible(netbk->wq,
1560 rx_work_todo(netbk) ||
1561 tx_work_todo(netbk) ||
1562 kthread_should_stop());
1563 cond_resched();
1564
1565 if (kthread_should_stop())
1566 break;
1567
1568 if (rx_work_todo(netbk))
1569 xen_netbk_rx_action(netbk);
1570
1571 if (tx_work_todo(netbk))
1572 xen_netbk_tx_action(netbk);
1573 }
1574
1575 return 0;
1576}
1577
1578void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
1579{
1580 struct gnttab_unmap_grant_ref op;
1581
1582 if (vif->tx.sring) {
1583 gnttab_set_unmap_op(&op, (unsigned long)vif->tx_comms_area->addr,
1584 GNTMAP_host_map, vif->tx_shmem_handle);
1585
1586 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
1587 BUG();
1588 }
1589
1590 if (vif->rx.sring) {
1591 gnttab_set_unmap_op(&op, (unsigned long)vif->rx_comms_area->addr,
1592 GNTMAP_host_map, vif->rx_shmem_handle);
1593
1594 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
1595 BUG();
1596 }
1597 if (vif->rx_comms_area)
1598 free_vm_area(vif->rx_comms_area);
1599 if (vif->tx_comms_area)
1600 free_vm_area(vif->tx_comms_area);
1601}
1602
1603int xen_netbk_map_frontend_rings(struct xenvif *vif,
1604 grant_ref_t tx_ring_ref,
1605 grant_ref_t rx_ring_ref)
1606{
1607 struct gnttab_map_grant_ref op;
1608 struct xen_netif_tx_sring *txs;
1609 struct xen_netif_rx_sring *rxs;
1610
1611 int err = -ENOMEM;
1612
1613 vif->tx_comms_area = alloc_vm_area(PAGE_SIZE);
1614 if (vif->tx_comms_area == NULL)
1615 goto err;
1616
1617 vif->rx_comms_area = alloc_vm_area(PAGE_SIZE);
1618 if (vif->rx_comms_area == NULL)
1619 goto err;
1620
1621 gnttab_set_map_op(&op, (unsigned long)vif->tx_comms_area->addr,
1622 GNTMAP_host_map, tx_ring_ref, vif->domid);
1623
1624 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
1625 BUG();
1626
1627 if (op.status) {
1628 netdev_warn(vif->dev,
1629 "failed to map tx ring. err=%d status=%d\n",
1630 err, op.status);
1631 err = op.status;
1632 goto err;
1633 }
1634
1635 vif->tx_shmem_ref = tx_ring_ref;
1636 vif->tx_shmem_handle = op.handle;
1637
1638 txs = (struct xen_netif_tx_sring *)vif->tx_comms_area->addr;
1639 BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
1640
1641 gnttab_set_map_op(&op, (unsigned long)vif->rx_comms_area->addr,
1642 GNTMAP_host_map, rx_ring_ref, vif->domid);
1643
1644 if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
1645 BUG();
1646
1647 if (op.status) {
1648 netdev_warn(vif->dev,
1649 "failed to map rx ring. err=%d status=%d\n",
1650 err, op.status);
1651 err = op.status;
1652 goto err;
1653 }
1654
1655 vif->rx_shmem_ref = rx_ring_ref;
1656 vif->rx_shmem_handle = op.handle;
1657 vif->rx_req_cons_peek = 0;
1658
1659 rxs = (struct xen_netif_rx_sring *)vif->rx_comms_area->addr;
1660 BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
1661
1662 return 0;
1663
1664err:
1665 xen_netbk_unmap_frontend_rings(vif);
1666 return err;
1667}
1668
1669static int __init netback_init(void)
1670{
1671 int i;
1672 int rc = 0;
1673 int group;
1674
1675 if (!xen_pv_domain())
1676 return -ENODEV;
1677
1678 xen_netbk_group_nr = num_online_cpus();
1679 xen_netbk = vzalloc(sizeof(struct xen_netbk) * xen_netbk_group_nr);
1680 if (!xen_netbk) {
1681 printk(KERN_ALERT "%s: out of memory\n", __func__);
1682 return -ENOMEM;
1683 }
1684
1685 for (group = 0; group < xen_netbk_group_nr; group++) {
1686 struct xen_netbk *netbk = &xen_netbk[group];
1687 skb_queue_head_init(&netbk->rx_queue);
1688 skb_queue_head_init(&netbk->tx_queue);
1689
1690 init_timer(&netbk->net_timer);
1691 netbk->net_timer.data = (unsigned long)netbk;
1692 netbk->net_timer.function = xen_netbk_alarm;
1693
1694 netbk->pending_cons = 0;
1695 netbk->pending_prod = MAX_PENDING_REQS;
1696 for (i = 0; i < MAX_PENDING_REQS; i++)
1697 netbk->pending_ring[i] = i;
1698
1699 init_waitqueue_head(&netbk->wq);
1700 netbk->task = kthread_create(xen_netbk_kthread,
1701 (void *)netbk,
1702 "netback/%u", group);
1703
1704 if (IS_ERR(netbk->task)) {
1705 printk(KERN_ALERT "kthread_run() fails at netback\n");
1706 del_timer(&netbk->net_timer);
1707 rc = PTR_ERR(netbk->task);
1708 goto failed_init;
1709 }
1710
1711 kthread_bind(netbk->task, group);
1712
1713 INIT_LIST_HEAD(&netbk->net_schedule_list);
1714
1715 spin_lock_init(&netbk->net_schedule_list_lock);
1716
1717 atomic_set(&netbk->netfront_count, 0);
1718
1719 wake_up_process(netbk->task);
1720 }
1721
1722 rc = xenvif_xenbus_init();
1723 if (rc)
1724 goto failed_init;
1725
1726 return 0;
1727
1728failed_init:
1729 while (--group >= 0) {
1730 struct xen_netbk *netbk = &xen_netbk[group];
1731 for (i = 0; i < MAX_PENDING_REQS; i++) {
1732 if (netbk->mmap_pages[i])
1733 __free_page(netbk->mmap_pages[i]);
1734 }
1735 del_timer(&netbk->net_timer);
1736 kthread_stop(netbk->task);
1737 }
1738 vfree(xen_netbk);
1739 return rc;
1740
1741}
1742
1743module_init(netback_init);
1744
1745MODULE_LICENSE("Dual BSD/GPL");
1746MODULE_ALIAS("xen-backend:vif");