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Root/drivers/net/xen-netfront.c

1	/*
2	* Virtual network driver for conversing with remote driver backends.
3	*
4	* Copyright (c) 2002-2005, K A Fraser
5	* Copyright (c) 2005, XenSource Ltd
6	*
7	* This program is free software; you can redistribute it and/or
8	* modify it under the terms of the GNU General Public License version 2
9	* as published by the Free Software Foundation; or, when distributed
10	* separately from the Linux kernel or incorporated into other
11	* software packages, subject to the following license:
12	*
13	* Permission is hereby granted, free of charge, to any person obtaining a copy
14	* of this source file (the "Software"), to deal in the Software without
15	* restriction, including without limitation the rights to use, copy, modify,
16	* merge, publish, distribute, sublicense, and/or sell copies of the Software,
17	* and to permit persons to whom the Software is furnished to do so, subject to
18	* the following conditions:
19	*
20	* The above copyright notice and this permission notice shall be included in
21	* all copies or substantial portions of the Software.
22	*
23	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
24	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
25	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
26	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
27	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
28	* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
29	* IN THE SOFTWARE.
30	*/
31
32	#include <linux/module.h>
33	#include <linux/kernel.h>
34	#include <linux/netdevice.h>
35	#include <linux/etherdevice.h>
36	#include <linux/skbuff.h>
37	#include <linux/ethtool.h>
38	#include <linux/if_ether.h>
39	#include <linux/tcp.h>
40	#include <linux/udp.h>
41	#include <linux/moduleparam.h>
42	#include <linux/mm.h>
43	#include <net/ip.h>
44
45	#include <xen/xenbus.h>
46	#include <xen/events.h>
47	#include <xen/page.h>
48	#include <xen/grant_table.h>
49
50	#include <xen/interface/io/netif.h>
51	#include <xen/interface/memory.h>
52	#include <xen/interface/grant_table.h>
53
54	static struct ethtool_ops xennet_ethtool_ops;
55
56	struct netfront_cb {
57	struct page *page;
58	unsigned offset;
59	};
60
61	#define NETFRONT_SKB_CB(skb) ((struct netfront_cb *)((skb)->cb))
62
63	#define RX_COPY_THRESHOLD 256
64
65	#define GRANT_INVALID_REF 0
66
67	#define NET_TX_RING_SIZE __RING_SIZE((struct xen_netif_tx_sring *)0, PAGE_SIZE)
68	#define NET_RX_RING_SIZE __RING_SIZE((struct xen_netif_rx_sring *)0, PAGE_SIZE)
69	#define TX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)
70
71	struct netfront_info {
72	struct list_head list;
73	struct net_device *netdev;
74
75	struct napi_struct napi;
76
77	unsigned int evtchn;
78	struct xenbus_device *xbdev;
79
80	spinlock_t tx_lock;
81	struct xen_netif_tx_front_ring tx;
82	int tx_ring_ref;
83
84	/*
85	* {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
86	* are linked from tx_skb_freelist through skb_entry.link.
87	*
88	* NB. Freelist index entries are always going to be less than
89	* PAGE_OFFSET, whereas pointers to skbs will always be equal or
90	* greater than PAGE_OFFSET: we use this property to distinguish
91	* them.
92	*/
93	union skb_entry {
94	struct sk_buff *skb;
95	unsigned long link;
96	} tx_skbs[NET_TX_RING_SIZE];
97	grant_ref_t gref_tx_head;
98	grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
99	unsigned tx_skb_freelist;
100
101	spinlock_t rx_lock ____cacheline_aligned_in_smp;
102	struct xen_netif_rx_front_ring rx;
103	int rx_ring_ref;
104
105	/* Receive-ring batched refills. */
106	#define RX_MIN_TARGET 8
107	#define RX_DFL_MIN_TARGET 64
108	#define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)
109	unsigned rx_min_target, rx_max_target, rx_target;
110	struct sk_buff_head rx_batch;
111
112	struct timer_list rx_refill_timer;
113
114	struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
115	grant_ref_t gref_rx_head;
116	grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
117
118	unsigned long rx_pfn_array[NET_RX_RING_SIZE];
119	struct multicall_entry rx_mcl[NET_RX_RING_SIZE+1];
120	struct mmu_update rx_mmu[NET_RX_RING_SIZE];
121	};
122
123	struct netfront_rx_info {
124	struct xen_netif_rx_response rx;
125	struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
126	};
127
128	static void skb_entry_set_link(union skb_entry *list, unsigned short id)
129	{
130	list->link = id;
131	}
132
133	static int skb_entry_is_link(const union skb_entry *list)
134	{
135	BUILD_BUG_ON(sizeof(list->skb) != sizeof(list->link));
136	return ((unsigned long)list->skb < PAGE_OFFSET);
137	}
138
139	/*
140	* Access macros for acquiring freeing slots in tx_skbs[].
141	*/
142
143	static void add_id_to_freelist(unsigned head, union skb_entry list,
144	unsigned short id)
145	{
146	skb_entry_set_link(&list[id], *head);
147	*head = id;
148	}
149
150	static unsigned short get_id_from_freelist(unsigned *head,
151	union skb_entry *list)
152	{
153	unsigned int id = *head;
154	*head = list[id].link;
155	return id;
156	}
157
158	static int xennet_rxidx(RING_IDX idx)
159	{
160	return idx & (NET_RX_RING_SIZE - 1);
161	}
162
163	static struct sk_buff xennet_get_rx_skb(struct netfront_info np,
164	RING_IDX ri)
165	{
166	int i = xennet_rxidx(ri);
167	struct sk_buff *skb = np->rx_skbs[i];
168	np->rx_skbs[i] = NULL;
169	return skb;
170	}
171
172	static grant_ref_t xennet_get_rx_ref(struct netfront_info *np,
173	RING_IDX ri)
174	{
175	int i = xennet_rxidx(ri);
176	grant_ref_t ref = np->grant_rx_ref[i];
177	np->grant_rx_ref[i] = GRANT_INVALID_REF;
178	return ref;
179	}
180
181	#ifdef CONFIG_SYSFS
182	static int xennet_sysfs_addif(struct net_device *netdev);
183	static void xennet_sysfs_delif(struct net_device *netdev);
184	#else /* !CONFIG_SYSFS */
185	#define xennet_sysfs_addif(dev) (0)
186	#define xennet_sysfs_delif(dev) do { } while (0)
187	#endif
188
189	static int xennet_can_sg(struct net_device *dev)
190	{
191	return dev->features & NETIF_F_SG;
192	}
193
194
195	static void rx_refill_timeout(unsigned long data)
196	{
197	struct net_device dev = (struct net_device )data;
198	struct netfront_info *np = netdev_priv(dev);
199	napi_schedule(&np->napi);
200	}
201
202	static int netfront_tx_slot_available(struct netfront_info *np)
203	{
204	return ((np->tx.req_prod_pvt - np->tx.rsp_cons) <
205	(TX_MAX_TARGET - MAX_SKB_FRAGS - 2));
206	}
207
208	static void xennet_maybe_wake_tx(struct net_device *dev)
209	{
210	struct netfront_info *np = netdev_priv(dev);
211
212	if (unlikely(netif_queue_stopped(dev)) &&
213	netfront_tx_slot_available(np) &&
214	likely(netif_running(dev)))
215	netif_wake_queue(dev);
216	}
217
218	static void xennet_alloc_rx_buffers(struct net_device *dev)
219	{
220	unsigned short id;
221	struct netfront_info *np = netdev_priv(dev);
222	struct sk_buff *skb;
223	struct page *page;
224	int i, batch_target, notify;
225	RING_IDX req_prod = np->rx.req_prod_pvt;
226	grant_ref_t ref;
227	unsigned long pfn;
228	void *vaddr;
229	struct xen_netif_rx_request *req;
230
231	if (unlikely(!netif_carrier_ok(dev)))
232	return;
233
234	/*
235	* Allocate skbuffs greedily, even though we batch updates to the
236	* receive ring. This creates a less bursty demand on the memory
237	* allocator, so should reduce the chance of failed allocation requests
238	* both for ourself and for other kernel subsystems.
239	*/
240	batch_target = np->rx_target - (req_prod - np->rx.rsp_cons);
241	for (i = skb_queue_len(&np->rx_batch); i < batch_target; i++) {
242	skb = __netdev_alloc_skb(dev, RX_COPY_THRESHOLD + NET_IP_ALIGN,
243	GFP_ATOMIC \| __GFP_NOWARN);
244	if (unlikely(!skb))
245	goto no_skb;
246
247	/* Align ip header to a 16 bytes boundary */
248	skb_reserve(skb, NET_IP_ALIGN);
249
250	page = alloc_page(GFP_ATOMIC \| __GFP_NOWARN);
251	if (!page) {
252	kfree_skb(skb);
253	no_skb:
254	/* Any skbuffs queued for refill? Force them out. */
255	if (i != 0)
256	goto refill;
257	/* Could not allocate any skbuffs. Try again later. */
258	mod_timer(&np->rx_refill_timer,
259	jiffies + (HZ/10));
260	break;
261	}
262
263	skb_shinfo(skb)->frags[0].page = page;
264	skb_shinfo(skb)->nr_frags = 1;
265	__skb_queue_tail(&np->rx_batch, skb);
266	}
267
268	/* Is the batch large enough to be worthwhile? */
269	if (i < (np->rx_target/2)) {
270	if (req_prod > np->rx.sring->req_prod)
271	goto push;
272	return;
273	}
274
275	/* Adjust our fill target if we risked running out of buffers. */
276	if (((req_prod - np->rx.sring->rsp_prod) < (np->rx_target / 4)) &&
277	((np->rx_target *= 2) > np->rx_max_target))
278	np->rx_target = np->rx_max_target;
279
280	refill:
281	for (i = 0; ; i++) {
282	skb = __skb_dequeue(&np->rx_batch);
283	if (skb == NULL)
284	break;
285
286	skb->dev = dev;
287
288	id = xennet_rxidx(req_prod + i);
289
290	BUG_ON(np->rx_skbs[id]);
291	np->rx_skbs[id] = skb;
292
293	ref = gnttab_claim_grant_reference(&np->gref_rx_head);
294	BUG_ON((signed short)ref < 0);
295	np->grant_rx_ref[id] = ref;
296
297	pfn = page_to_pfn(skb_shinfo(skb)->frags[0].page);
298	vaddr = page_address(skb_shinfo(skb)->frags[0].page);
299
300	req = RING_GET_REQUEST(&np->rx, req_prod + i);
301	gnttab_grant_foreign_access_ref(ref,
302	np->xbdev->otherend_id,
303	pfn_to_mfn(pfn),
304	0);
305
306	req->id = id;
307	req->gref = ref;
308	}
309
310	wmb(); /* barrier so backend seens requests */
311
312	/* Above is a suitable barrier to ensure backend will see requests. */
313	np->rx.req_prod_pvt = req_prod + i;
314	push:
315	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->rx, notify);
316	if (notify)
317	notify_remote_via_irq(np->netdev->irq);
318	}
319
320	static int xennet_open(struct net_device *dev)
321	{
322	struct netfront_info *np = netdev_priv(dev);
323
324	napi_enable(&np->napi);
325
326	spin_lock_bh(&np->rx_lock);
327	if (netif_carrier_ok(dev)) {
328	xennet_alloc_rx_buffers(dev);
329	np->rx.sring->rsp_event = np->rx.rsp_cons + 1;
330	if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
331	napi_schedule(&np->napi);
332	}
333	spin_unlock_bh(&np->rx_lock);
334
335	netif_start_queue(dev);
336
337	return 0;
338	}
339
340	static void xennet_tx_buf_gc(struct net_device *dev)
341	{
342	RING_IDX cons, prod;
343	unsigned short id;
344	struct netfront_info *np = netdev_priv(dev);
345	struct sk_buff *skb;
346
347	BUG_ON(!netif_carrier_ok(dev));
348
349	do {
350	prod = np->tx.sring->rsp_prod;
351	rmb(); /* Ensure we see responses up to 'rp'. */
352
353	for (cons = np->tx.rsp_cons; cons != prod; cons++) {
354	struct xen_netif_tx_response *txrsp;
355
356	txrsp = RING_GET_RESPONSE(&np->tx, cons);
357	if (txrsp->status == NETIF_RSP_NULL)
358	continue;
359
360	id = txrsp->id;
361	skb = np->tx_skbs[id].skb;
362	if (unlikely(gnttab_query_foreign_access(
363	np->grant_tx_ref[id]) != 0)) {
364	printk(KERN_ALERT "xennet_tx_buf_gc: warning "
365	"-- grant still in use by backend "
366	"domain.\n");
367	BUG();
368	}
369	gnttab_end_foreign_access_ref(
370	np->grant_tx_ref[id], GNTMAP_readonly);
371	gnttab_release_grant_reference(
372	&np->gref_tx_head, np->grant_tx_ref[id]);
373	np->grant_tx_ref[id] = GRANT_INVALID_REF;
374	add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, id);
375	dev_kfree_skb_irq(skb);
376	}
377
378	np->tx.rsp_cons = prod;
379
380	/*
381	* Set a new event, then check for race with update of tx_cons.
382	* Note that it is essential to schedule a callback, no matter
383	* how few buffers are pending. Even if there is space in the
384	* transmit ring, higher layers may be blocked because too much
385	* data is outstanding: in such cases notification from Xen is
386	* likely to be the only kick that we'll get.
387	*/
388	np->tx.sring->rsp_event =
389	prod + ((np->tx.sring->req_prod - prod) >> 1) + 1;
390	mb(); /* update shared area */
391	} while ((cons == prod) && (prod != np->tx.sring->rsp_prod));
392
393	xennet_maybe_wake_tx(dev);
394	}
395
396	static void xennet_make_frags(struct sk_buff skb, struct net_device dev,
397	struct xen_netif_tx_request *tx)
398	{
399	struct netfront_info *np = netdev_priv(dev);
400	char *data = skb->data;
401	unsigned long mfn;
402	RING_IDX prod = np->tx.req_prod_pvt;
403	int frags = skb_shinfo(skb)->nr_frags;
404	unsigned int offset = offset_in_page(data);
405	unsigned int len = skb_headlen(skb);
406	unsigned int id;
407	grant_ref_t ref;
408	int i;
409
410	/* While the header overlaps a page boundary (including being
411	larger than a page), split it it into page-sized chunks. */
412	while (len > PAGE_SIZE - offset) {
413	tx->size = PAGE_SIZE - offset;
414	tx->flags \|= NETTXF_more_data;
415	len -= tx->size;
416	data += tx->size;
417	offset = 0;
418
419	id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
420	np->tx_skbs[id].skb = skb_get(skb);
421	tx = RING_GET_REQUEST(&np->tx, prod++);
422	tx->id = id;
423	ref = gnttab_claim_grant_reference(&np->gref_tx_head);
424	BUG_ON((signed short)ref < 0);
425
426	mfn = virt_to_mfn(data);
427	gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
428	mfn, GNTMAP_readonly);
429
430	tx->gref = np->grant_tx_ref[id] = ref;
431	tx->offset = offset;
432	tx->size = len;
433	tx->flags = 0;
434	}
435
436	/* Grant backend access to each skb fragment page. */
437	for (i = 0; i < frags; i++) {
438	skb_frag_t *frag = skb_shinfo(skb)->frags + i;
439
440	tx->flags \|= NETTXF_more_data;
441
442	id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
443	np->tx_skbs[id].skb = skb_get(skb);
444	tx = RING_GET_REQUEST(&np->tx, prod++);
445	tx->id = id;
446	ref = gnttab_claim_grant_reference(&np->gref_tx_head);
447	BUG_ON((signed short)ref < 0);
448
449	mfn = pfn_to_mfn(page_to_pfn(frag->page));
450	gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
451	mfn, GNTMAP_readonly);
452
453	tx->gref = np->grant_tx_ref[id] = ref;
454	tx->offset = frag->page_offset;
455	tx->size = frag->size;
456	tx->flags = 0;
457	}
458
459	np->tx.req_prod_pvt = prod;
460	}
461
462	static int xennet_start_xmit(struct sk_buff skb, struct net_device dev)
463	{
464	unsigned short id;
465	struct netfront_info *np = netdev_priv(dev);
466	struct xen_netif_tx_request *tx;
467	struct xen_netif_extra_info *extra;
468	char *data = skb->data;
469	RING_IDX i;
470	grant_ref_t ref;
471	unsigned long mfn;
472	int notify;
473	int frags = skb_shinfo(skb)->nr_frags;
474	unsigned int offset = offset_in_page(data);
475	unsigned int len = skb_headlen(skb);
476
477	frags += DIV_ROUND_UP(offset + len, PAGE_SIZE);
478	if (unlikely(frags > MAX_SKB_FRAGS + 1)) {
479	printk(KERN_ALERT "xennet: skb rides the rocket: %d frags\n",
480	frags);
481	dump_stack();
482	goto drop;
483	}
484
485	spin_lock_irq(&np->tx_lock);
486
487	if (unlikely(!netif_carrier_ok(dev) \|\|
488	(frags > 1 && !xennet_can_sg(dev)) \|\|
489	netif_needs_gso(dev, skb))) {
490	spin_unlock_irq(&np->tx_lock);
491	goto drop;
492	}
493
494	i = np->tx.req_prod_pvt;
495
496	id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
497	np->tx_skbs[id].skb = skb;
498
499	tx = RING_GET_REQUEST(&np->tx, i);
500
501	tx->id = id;
502	ref = gnttab_claim_grant_reference(&np->gref_tx_head);
503	BUG_ON((signed short)ref < 0);
504	mfn = virt_to_mfn(data);
505	gnttab_grant_foreign_access_ref(
506	ref, np->xbdev->otherend_id, mfn, GNTMAP_readonly);
507	tx->gref = np->grant_tx_ref[id] = ref;
508	tx->offset = offset;
509	tx->size = len;
510	extra = NULL;
511
512	tx->flags = 0;
513	if (skb->ip_summed == CHECKSUM_PARTIAL)
514	/* local packet? */
515	tx->flags \|= NETTXF_csum_blank \| NETTXF_data_validated;
516	else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
517	/* remote but checksummed. */
518	tx->flags \|= NETTXF_data_validated;
519
520	if (skb_shinfo(skb)->gso_size) {
521	struct xen_netif_extra_info *gso;
522
523	gso = (struct xen_netif_extra_info *)
524	RING_GET_REQUEST(&np->tx, ++i);
525
526	if (extra)
527	extra->flags \|= XEN_NETIF_EXTRA_FLAG_MORE;
528	else
529	tx->flags \|= NETTXF_extra_info;
530
531	gso->u.gso.size = skb_shinfo(skb)->gso_size;
532	gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
533	gso->u.gso.pad = 0;
534	gso->u.gso.features = 0;
535
536	gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
537	gso->flags = 0;
538	extra = gso;
539	}
540
541	np->tx.req_prod_pvt = i + 1;
542
543	xennet_make_frags(skb, dev, tx);
544	tx->size = skb->len;
545
546	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->tx, notify);
547	if (notify)
548	notify_remote_via_irq(np->netdev->irq);
549
550	dev->stats.tx_bytes += skb->len;
551	dev->stats.tx_packets++;
552
553	/* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
554	xennet_tx_buf_gc(dev);
555
556	if (!netfront_tx_slot_available(np))
557	netif_stop_queue(dev);
558
559	spin_unlock_irq(&np->tx_lock);
560
561	return 0;
562
563	drop:
564	dev->stats.tx_dropped++;
565	dev_kfree_skb(skb);
566	return 0;
567	}
568
569	static int xennet_close(struct net_device *dev)
570	{
571	struct netfront_info *np = netdev_priv(dev);
572	netif_stop_queue(np->netdev);
573	napi_disable(&np->napi);
574	return 0;
575	}
576
577	static void xennet_move_rx_slot(struct netfront_info np, struct sk_buff skb,
578	grant_ref_t ref)
579	{
580	int new = xennet_rxidx(np->rx.req_prod_pvt);
581
582	BUG_ON(np->rx_skbs[new]);
583	np->rx_skbs[new] = skb;
584	np->grant_rx_ref[new] = ref;
585	RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->id = new;
586	RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->gref = ref;
587	np->rx.req_prod_pvt++;
588	}
589
590	static int xennet_get_extras(struct netfront_info *np,
591	struct xen_netif_extra_info *extras,
592	RING_IDX rp)
593
594	{
595	struct xen_netif_extra_info *extra;
596	struct device *dev = &np->netdev->dev;
597	RING_IDX cons = np->rx.rsp_cons;
598	int err = 0;
599
600	do {
601	struct sk_buff *skb;
602	grant_ref_t ref;
603
604	if (unlikely(cons + 1 == rp)) {
605	if (net_ratelimit())
606	dev_warn(dev, "Missing extra info\n");
607	err = -EBADR;
608	break;
609	}
610
611	extra = (struct xen_netif_extra_info *)
612	RING_GET_RESPONSE(&np->rx, ++cons);
613
614	if (unlikely(!extra->type \|\|
615	extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
616	if (net_ratelimit())
617	dev_warn(dev, "Invalid extra type: %d\n",
618	extra->type);
619	err = -EINVAL;
620	} else {
621	memcpy(&extras[extra->type - 1], extra,
622	sizeof(*extra));
623	}
624
625	skb = xennet_get_rx_skb(np, cons);
626	ref = xennet_get_rx_ref(np, cons);
627	xennet_move_rx_slot(np, skb, ref);
628	} while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);
629
630	np->rx.rsp_cons = cons;
631	return err;
632	}
633
634	static int xennet_get_responses(struct netfront_info *np,
635	struct netfront_rx_info *rinfo, RING_IDX rp,
636	struct sk_buff_head *list)
637	{
638	struct xen_netif_rx_response *rx = &rinfo->rx;
639	struct xen_netif_extra_info *extras = rinfo->extras;
640	struct device *dev = &np->netdev->dev;
641	RING_IDX cons = np->rx.rsp_cons;
642	struct sk_buff *skb = xennet_get_rx_skb(np, cons);
643	grant_ref_t ref = xennet_get_rx_ref(np, cons);
644	int max = MAX_SKB_FRAGS + (rx->status <= RX_COPY_THRESHOLD);
645	int frags = 1;
646	int err = 0;
647	unsigned long ret;
648
649	if (rx->flags & NETRXF_extra_info) {
650	err = xennet_get_extras(np, extras, rp);
651	cons = np->rx.rsp_cons;
652	}
653
654	for (;;) {
655	if (unlikely(rx->status < 0 \|\|
656	rx->offset + rx->status > PAGE_SIZE)) {
657	if (net_ratelimit())
658	dev_warn(dev, "rx->offset: %x, size: %u\n",
659	rx->offset, rx->status);
660	xennet_move_rx_slot(np, skb, ref);
661	err = -EINVAL;
662	goto next;
663	}
664
665	/*
666	* This definitely indicates a bug, either in this driver or in
667	* the backend driver. In future this should flag the bad
668	* situation to the system controller to reboot the backed.
669	*/
670	if (ref == GRANT_INVALID_REF) {
671	if (net_ratelimit())
672	dev_warn(dev, "Bad rx response id %d.\n",
673	rx->id);
674	err = -EINVAL;
675	goto next;
676	}
677
678	ret = gnttab_end_foreign_access_ref(ref, 0);
679	BUG_ON(!ret);
680
681	gnttab_release_grant_reference(&np->gref_rx_head, ref);
682
683	__skb_queue_tail(list, skb);
684
685	next:
686	if (!(rx->flags & NETRXF_more_data))
687	break;
688
689	if (cons + frags == rp) {
690	if (net_ratelimit())
691	dev_warn(dev, "Need more frags\n");
692	err = -ENOENT;
693	break;
694	}
695
696	rx = RING_GET_RESPONSE(&np->rx, cons + frags);
697	skb = xennet_get_rx_skb(np, cons + frags);
698	ref = xennet_get_rx_ref(np, cons + frags);
699	frags++;
700	}
701
702	if (unlikely(frags > max)) {
703	if (net_ratelimit())
704	dev_warn(dev, "Too many frags\n");
705	err = -E2BIG;
706	}
707
708	if (unlikely(err))
709	np->rx.rsp_cons = cons + frags;
710
711	return err;
712	}
713
714	static int xennet_set_skb_gso(struct sk_buff *skb,
715	struct xen_netif_extra_info *gso)
716	{
717	if (!gso->u.gso.size) {
718	if (net_ratelimit())
719	printk(KERN_WARNING "GSO size must not be zero.\n");
720	return -EINVAL;
721	}
722
723	/* Currently only TCPv4 S.O. is supported. */
724	if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
725	if (net_ratelimit())
726	printk(KERN_WARNING "Bad GSO type %d.\n", gso->u.gso.type);
727	return -EINVAL;
728	}
729
730	skb_shinfo(skb)->gso_size = gso->u.gso.size;
731	skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
732
733	/* Header must be checked, and gso_segs computed. */
734	skb_shinfo(skb)->gso_type \|= SKB_GSO_DODGY;
735	skb_shinfo(skb)->gso_segs = 0;
736
737	return 0;
738	}
739
740	static RING_IDX xennet_fill_frags(struct netfront_info *np,
741	struct sk_buff *skb,
742	struct sk_buff_head *list)
743	{
744	struct skb_shared_info *shinfo = skb_shinfo(skb);
745	int nr_frags = shinfo->nr_frags;
746	RING_IDX cons = np->rx.rsp_cons;
747	skb_frag_t *frag = shinfo->frags + nr_frags;
748	struct sk_buff *nskb;
749
750	while ((nskb = __skb_dequeue(list))) {
751	struct xen_netif_rx_response *rx =
752	RING_GET_RESPONSE(&np->rx, ++cons);
753
754	frag->page = skb_shinfo(nskb)->frags[0].page;
755	frag->page_offset = rx->offset;
756	frag->size = rx->status;
757
758	skb->data_len += rx->status;
759
760	skb_shinfo(nskb)->nr_frags = 0;
761	kfree_skb(nskb);
762
763	frag++;
764	nr_frags++;
765	}
766
767	shinfo->nr_frags = nr_frags;
768	return cons;
769	}
770
771	static int skb_checksum_setup(struct sk_buff *skb)
772	{
773	struct iphdr *iph;
774	unsigned char *th;
775	int err = -EPROTO;
776
777	if (skb->protocol != htons(ETH_P_IP))
778	goto out;
779
780	iph = (void *)skb->data;
781	th = skb->data + 4 * iph->ihl;
782	if (th >= skb_tail_pointer(skb))
783	goto out;
784
785	skb->csum_start = th - skb->head;
786	switch (iph->protocol) {
787	case IPPROTO_TCP:
788	skb->csum_offset = offsetof(struct tcphdr, check);
789	break;
790	case IPPROTO_UDP:
791	skb->csum_offset = offsetof(struct udphdr, check);
792	break;
793	default:
794	if (net_ratelimit())
795	printk(KERN_ERR "Attempting to checksum a non-"
796	"TCP/UDP packet, dropping a protocol"
797	" %d packet", iph->protocol);
798	goto out;
799	}
800
801	if ((th + skb->csum_offset + 2) > skb_tail_pointer(skb))
802	goto out;
803
804	err = 0;
805
806	out:
807	return err;
808	}
809
810	static int handle_incoming_queue(struct net_device *dev,
811	struct sk_buff_head *rxq)
812	{
813	int packets_dropped = 0;
814	struct sk_buff *skb;
815
816	while ((skb = __skb_dequeue(rxq)) != NULL) {
817	struct page *page = NETFRONT_SKB_CB(skb)->page;
818	void *vaddr = page_address(page);
819	unsigned offset = NETFRONT_SKB_CB(skb)->offset;
820
821	memcpy(skb->data, vaddr + offset,
822	skb_headlen(skb));
823
824	if (page != skb_shinfo(skb)->frags[0].page)
825	__free_page(page);
826
827	/* Ethernet work: Delayed to here as it peeks the header. */
828	skb->protocol = eth_type_trans(skb, dev);
829
830	if (skb->ip_summed == CHECKSUM_PARTIAL) {
831	if (skb_checksum_setup(skb)) {
832	kfree_skb(skb);
833	packets_dropped++;
834	dev->stats.rx_errors++;
835	continue;
836	}
837	}
838
839	dev->stats.rx_packets++;
840	dev->stats.rx_bytes += skb->len;
841
842	/* Pass it up. */
843	netif_receive_skb(skb);
844	}
845
846	return packets_dropped;
847	}
848
849	static int xennet_poll(struct napi_struct *napi, int budget)
850	{
851	struct netfront_info *np = container_of(napi, struct netfront_info, napi);
852	struct net_device *dev = np->netdev;
853	struct sk_buff *skb;
854	struct netfront_rx_info rinfo;
855	struct xen_netif_rx_response *rx = &rinfo.rx;
856	struct xen_netif_extra_info *extras = rinfo.extras;
857	RING_IDX i, rp;
858	int work_done;
859	struct sk_buff_head rxq;
860	struct sk_buff_head errq;
861	struct sk_buff_head tmpq;
862	unsigned long flags;
863	unsigned int len;
864	int err;
865
866	spin_lock(&np->rx_lock);
867
868	skb_queue_head_init(&rxq);
869	skb_queue_head_init(&errq);
870	skb_queue_head_init(&tmpq);
871
872	rp = np->rx.sring->rsp_prod;
873	rmb(); /* Ensure we see queued responses up to 'rp'. */
874
875	i = np->rx.rsp_cons;
876	work_done = 0;
877	while ((i != rp) && (work_done < budget)) {
878	memcpy(rx, RING_GET_RESPONSE(&np->rx, i), sizeof(*rx));
879	memset(extras, 0, sizeof(rinfo.extras));
880
881	err = xennet_get_responses(np, &rinfo, rp, &tmpq);
882
883	if (unlikely(err)) {
884	err:
885	while ((skb = __skb_dequeue(&tmpq)))
886	__skb_queue_tail(&errq, skb);
887	dev->stats.rx_errors++;
888	i = np->rx.rsp_cons;
889	continue;
890	}
891
892	skb = __skb_dequeue(&tmpq);
893
894	if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
895	struct xen_netif_extra_info *gso;
896	gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
897
898	if (unlikely(xennet_set_skb_gso(skb, gso))) {
899	__skb_queue_head(&tmpq, skb);
900	np->rx.rsp_cons += skb_queue_len(&tmpq);
901	goto err;
902	}
903	}
904
905	NETFRONT_SKB_CB(skb)->page = skb_shinfo(skb)->frags[0].page;
906	NETFRONT_SKB_CB(skb)->offset = rx->offset;
907
908	len = rx->status;
909	if (len > RX_COPY_THRESHOLD)
910	len = RX_COPY_THRESHOLD;
911	skb_put(skb, len);
912
913	if (rx->status > len) {
914	skb_shinfo(skb)->frags[0].page_offset =
915	rx->offset + len;
916	skb_shinfo(skb)->frags[0].size = rx->status - len;
917	skb->data_len = rx->status - len;
918	} else {
919	skb_shinfo(skb)->frags[0].page = NULL;
920	skb_shinfo(skb)->nr_frags = 0;
921	}
922
923	i = xennet_fill_frags(np, skb, &tmpq);
924
925	/*
926	* Truesize approximates the size of true data plus
927	* any supervisor overheads. Adding hypervisor
928	* overheads has been shown to significantly reduce
929	* achievable bandwidth with the default receive
930	* buffer size. It is therefore not wise to account
931	* for it here.
932	*
933	* After alloc_skb(RX_COPY_THRESHOLD), truesize is set
934	* to RX_COPY_THRESHOLD + the supervisor
935	* overheads. Here, we add the size of the data pulled
936	* in xennet_fill_frags().
937	*
938	* We also adjust for any unused space in the main
939	* data area by subtracting (RX_COPY_THRESHOLD -
940	* len). This is especially important with drivers
941	* which split incoming packets into header and data,
942	* using only 66 bytes of the main data area (see the
943	* e1000 driver for example.) On such systems,
944	* without this last adjustement, our achievable
945	* receive throughout using the standard receive
946	* buffer size was cut by 25%(!!!).
947	*/
948	skb->truesize += skb->data_len - (RX_COPY_THRESHOLD - len);
949	skb->len += skb->data_len;
950
951	if (rx->flags & NETRXF_csum_blank)
952	skb->ip_summed = CHECKSUM_PARTIAL;
953	else if (rx->flags & NETRXF_data_validated)
954	skb->ip_summed = CHECKSUM_UNNECESSARY;
955
956	__skb_queue_tail(&rxq, skb);
957
958	np->rx.rsp_cons = ++i;
959	work_done++;
960	}
961
962	__skb_queue_purge(&errq);
963
964	work_done -= handle_incoming_queue(dev, &rxq);
965
966	/* If we get a callback with very few responses, reduce fill target. */
967	/* NB. Note exponential increase, linear decrease. */
968	if (((np->rx.req_prod_pvt - np->rx.sring->rsp_prod) >
969	((3*np->rx_target) / 4)) &&
970	(--np->rx_target < np->rx_min_target))
971	np->rx_target = np->rx_min_target;
972
973	xennet_alloc_rx_buffers(dev);
974
975	if (work_done < budget) {
976	int more_to_do = 0;
977
978	local_irq_save(flags);
979
980	RING_FINAL_CHECK_FOR_RESPONSES(&np->rx, more_to_do);
981	if (!more_to_do)
982	__napi_complete(napi);
983
984	local_irq_restore(flags);
985	}
986
987	spin_unlock(&np->rx_lock);
988
989	return work_done;
990	}
991
992	static int xennet_change_mtu(struct net_device *dev, int mtu)
993	{
994	int max = xennet_can_sg(dev) ? 65535 - ETH_HLEN : ETH_DATA_LEN;
995
996	if (mtu > max)
997	return -EINVAL;
998	dev->mtu = mtu;
999	return 0;
1000	}
1001
1002	static void xennet_release_tx_bufs(struct netfront_info *np)
1003	{
1004	struct sk_buff *skb;
1005	int i;
1006
1007	for (i = 0; i < NET_TX_RING_SIZE; i++) {
1008	/* Skip over entries which are actually freelist references */
1009	if (skb_entry_is_link(&np->tx_skbs[i]))
1010	continue;
1011
1012	skb = np->tx_skbs[i].skb;
1013	gnttab_end_foreign_access_ref(np->grant_tx_ref[i],
1014	GNTMAP_readonly);
1015	gnttab_release_grant_reference(&np->gref_tx_head,
1016	np->grant_tx_ref[i]);
1017	np->grant_tx_ref[i] = GRANT_INVALID_REF;
1018	add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, i);
1019	dev_kfree_skb_irq(skb);
1020	}
1021	}
1022
1023	static void xennet_release_rx_bufs(struct netfront_info *np)
1024	{
1025	struct mmu_update *mmu = np->rx_mmu;
1026	struct multicall_entry *mcl = np->rx_mcl;
1027	struct sk_buff_head free_list;
1028	struct sk_buff *skb;
1029	unsigned long mfn;
1030	int xfer = 0, noxfer = 0, unused = 0;
1031	int id, ref;
1032
1033	dev_warn(&np->netdev->dev, "%s: fix me for copying receiver.\n",
1034	__func__);
1035	return;
1036
1037	skb_queue_head_init(&free_list);
1038
1039	spin_lock_bh(&np->rx_lock);
1040
1041	for (id = 0; id < NET_RX_RING_SIZE; id++) {
1042	ref = np->grant_rx_ref[id];
1043	if (ref == GRANT_INVALID_REF) {
1044	unused++;
1045	continue;
1046	}
1047
1048	skb = np->rx_skbs[id];
1049	mfn = gnttab_end_foreign_transfer_ref(ref);
1050	gnttab_release_grant_reference(&np->gref_rx_head, ref);
1051	np->grant_rx_ref[id] = GRANT_INVALID_REF;
1052
1053	if (0 == mfn) {
1054	skb_shinfo(skb)->nr_frags = 0;
1055	dev_kfree_skb(skb);
1056	noxfer++;
1057	continue;
1058	}
1059
1060	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
1061	/* Remap the page. */
1062	struct page *page = skb_shinfo(skb)->frags[0].page;
1063	unsigned long pfn = page_to_pfn(page);
1064	void *vaddr = page_address(page);
1065
1066	MULTI_update_va_mapping(mcl, (unsigned long)vaddr,
1067	mfn_pte(mfn, PAGE_KERNEL),
1068	0);
1069	mcl++;
1070	mmu->ptr = ((u64)mfn << PAGE_SHIFT)
1071	\| MMU_MACHPHYS_UPDATE;
1072	mmu->val = pfn;
1073	mmu++;
1074
1075	set_phys_to_machine(pfn, mfn);
1076	}
1077	__skb_queue_tail(&free_list, skb);
1078	xfer++;
1079	}
1080
1081	dev_info(&np->netdev->dev, "%s: %d xfer, %d noxfer, %d unused\n",
1082	__func__, xfer, noxfer, unused);
1083
1084	if (xfer) {
1085	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
1086	/* Do all the remapping work and M2P updates. */
1087	MULTI_mmu_update(mcl, np->rx_mmu, mmu - np->rx_mmu,
1088	NULL, DOMID_SELF);
1089	mcl++;
1090	HYPERVISOR_multicall(np->rx_mcl, mcl - np->rx_mcl);
1091	}
1092	}
1093
1094	__skb_queue_purge(&free_list);
1095
1096	spin_unlock_bh(&np->rx_lock);
1097	}
1098
1099	static void xennet_uninit(struct net_device *dev)
1100	{
1101	struct netfront_info *np = netdev_priv(dev);
1102	xennet_release_tx_bufs(np);
1103	xennet_release_rx_bufs(np);
1104	gnttab_free_grant_references(np->gref_tx_head);
1105	gnttab_free_grant_references(np->gref_rx_head);
1106	}
1107
1108	static const struct net_device_ops xennet_netdev_ops = {
1109	.ndo_open = xennet_open,
1110	.ndo_uninit = xennet_uninit,
1111	.ndo_stop = xennet_close,
1112	.ndo_start_xmit = xennet_start_xmit,
1113	.ndo_change_mtu = xennet_change_mtu,
1114	.ndo_set_mac_address = eth_mac_addr,
1115	.ndo_validate_addr = eth_validate_addr,
1116	};
1117
1118	static struct net_device * __devinit xennet_create_dev(struct xenbus_device *dev)
1119	{
1120	int i, err;
1121	struct net_device *netdev;
1122	struct netfront_info *np;
1123
1124	netdev = alloc_etherdev(sizeof(struct netfront_info));
1125	if (!netdev) {
1126	printk(KERN_WARNING "%s> alloc_etherdev failed.\n",
1127	__func__);
1128	return ERR_PTR(-ENOMEM);
1129	}
1130
1131	np = netdev_priv(netdev);
1132	np->xbdev = dev;
1133
1134	spin_lock_init(&np->tx_lock);
1135	spin_lock_init(&np->rx_lock);
1136
1137	skb_queue_head_init(&np->rx_batch);
1138	np->rx_target = RX_DFL_MIN_TARGET;
1139	np->rx_min_target = RX_DFL_MIN_TARGET;
1140	np->rx_max_target = RX_MAX_TARGET;
1141
1142	init_timer(&np->rx_refill_timer);
1143	np->rx_refill_timer.data = (unsigned long)netdev;
1144	np->rx_refill_timer.function = rx_refill_timeout;
1145
1146	/* Initialise tx_skbs as a free chain containing every entry. */
1147	np->tx_skb_freelist = 0;
1148	for (i = 0; i < NET_TX_RING_SIZE; i++) {
1149	skb_entry_set_link(&np->tx_skbs[i], i+1);
1150	np->grant_tx_ref[i] = GRANT_INVALID_REF;
1151	}
1152
1153	/* Clear out rx_skbs */
1154	for (i = 0; i < NET_RX_RING_SIZE; i++) {
1155	np->rx_skbs[i] = NULL;
1156	np->grant_rx_ref[i] = GRANT_INVALID_REF;
1157	}
1158
1159	/* A grant for every tx ring slot */
1160	if (gnttab_alloc_grant_references(TX_MAX_TARGET,
1161	&np->gref_tx_head) < 0) {
1162	printk(KERN_ALERT "#### netfront can't alloc tx grant refs\n");
1163	err = -ENOMEM;
1164	goto exit;
1165	}
1166	/* A grant for every rx ring slot */
1167	if (gnttab_alloc_grant_references(RX_MAX_TARGET,
1168	&np->gref_rx_head) < 0) {
1169	printk(KERN_ALERT "#### netfront can't alloc rx grant refs\n");
1170	err = -ENOMEM;
1171	goto exit_free_tx;
1172	}
1173
1174	netdev->netdev_ops = &xennet_netdev_ops;
1175
1176	netif_napi_add(netdev, &np->napi, xennet_poll, 64);
1177	netdev->features = NETIF_F_IP_CSUM;
1178
1179	SET_ETHTOOL_OPS(netdev, &xennet_ethtool_ops);
1180	SET_NETDEV_DEV(netdev, &dev->dev);
1181
1182	np->netdev = netdev;
1183
1184	netif_carrier_off(netdev);
1185
1186	return netdev;
1187
1188	exit_free_tx:
1189	gnttab_free_grant_references(np->gref_tx_head);
1190	exit:
1191	free_netdev(netdev);
1192	return ERR_PTR(err);
1193	}
1194
1195	/**
1196	* Entry point to this code when a new device is created. Allocate the basic
1197	* structures and the ring buffers for communication with the backend, and
1198	* inform the backend of the appropriate details for those.
1199	*/
1200	static int __devinit netfront_probe(struct xenbus_device *dev,
1201	const struct xenbus_device_id *id)
1202	{
1203	int err;
1204	struct net_device *netdev;
1205	struct netfront_info *info;
1206
1207	netdev = xennet_create_dev(dev);
1208	if (IS_ERR(netdev)) {
1209	err = PTR_ERR(netdev);
1210	xenbus_dev_fatal(dev, err, "creating netdev");
1211	return err;
1212	}
1213
1214	info = netdev_priv(netdev);
1215	dev_set_drvdata(&dev->dev, info);
1216
1217	err = register_netdev(info->netdev);
1218	if (err) {
1219	printk(KERN_WARNING "%s: register_netdev err=%d\n",
1220	__func__, err);
1221	goto fail;
1222	}
1223
1224	err = xennet_sysfs_addif(info->netdev);
1225	if (err) {
1226	unregister_netdev(info->netdev);
1227	printk(KERN_WARNING "%s: add sysfs failed err=%d\n",
1228	__func__, err);
1229	goto fail;
1230	}
1231
1232	return 0;
1233
1234	fail:
1235	free_netdev(netdev);
1236	dev_set_drvdata(&dev->dev, NULL);
1237	return err;
1238	}
1239
1240	static void xennet_end_access(int ref, void *page)
1241	{
1242	/* This frees the page as a side-effect */
1243	if (ref != GRANT_INVALID_REF)
1244	gnttab_end_foreign_access(ref, 0, (unsigned long)page);
1245	}
1246
1247	static void xennet_disconnect_backend(struct netfront_info *info)
1248	{
1249	/* Stop old i/f to prevent errors whilst we rebuild the state. */
1250	spin_lock_bh(&info->rx_lock);
1251	spin_lock_irq(&info->tx_lock);
1252	netif_carrier_off(info->netdev);
1253	spin_unlock_irq(&info->tx_lock);
1254	spin_unlock_bh(&info->rx_lock);
1255
1256	if (info->netdev->irq)
1257	unbind_from_irqhandler(info->netdev->irq, info->netdev);
1258	info->evtchn = info->netdev->irq = 0;
1259
1260	/* End access and free the pages */
1261	xennet_end_access(info->tx_ring_ref, info->tx.sring);
1262	xennet_end_access(info->rx_ring_ref, info->rx.sring);
1263
1264	info->tx_ring_ref = GRANT_INVALID_REF;
1265	info->rx_ring_ref = GRANT_INVALID_REF;
1266	info->tx.sring = NULL;
1267	info->rx.sring = NULL;
1268	}
1269
1270	/**
1271	* We are reconnecting to the backend, due to a suspend/resume, or a backend
1272	* driver restart. We tear down our netif structure and recreate it, but
1273	* leave the device-layer structures intact so that this is transparent to the
1274	* rest of the kernel.
1275	*/
1276	static int netfront_resume(struct xenbus_device *dev)
1277	{
1278	struct netfront_info *info = dev_get_drvdata(&dev->dev);
1279
1280	dev_dbg(&dev->dev, "%s\n", dev->nodename);
1281
1282	xennet_disconnect_backend(info);
1283	return 0;
1284	}
1285
1286	static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
1287	{
1288	char s, e, *macstr;
1289	int i;
1290
1291	macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
1292	if (IS_ERR(macstr))
1293	return PTR_ERR(macstr);
1294
1295	for (i = 0; i < ETH_ALEN; i++) {
1296	mac[i] = simple_strtoul(s, &e, 16);
1297	if ((s == e) \|\| (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
1298	kfree(macstr);
1299	return -ENOENT;
1300	}
1301	s = e+1;
1302	}
1303
1304	kfree(macstr);
1305	return 0;
1306	}
1307
1308	static irqreturn_t xennet_interrupt(int irq, void *dev_id)
1309	{
1310	struct net_device *dev = dev_id;
1311	struct netfront_info *np = netdev_priv(dev);
1312	unsigned long flags;
1313
1314	spin_lock_irqsave(&np->tx_lock, flags);
1315
1316	if (likely(netif_carrier_ok(dev))) {
1317	xennet_tx_buf_gc(dev);
1318	/* Under tx_lock: protects access to rx shared-ring indexes. */
1319	if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
1320	napi_schedule(&np->napi);
1321	}
1322
1323	spin_unlock_irqrestore(&np->tx_lock, flags);
1324
1325	return IRQ_HANDLED;
1326	}
1327
1328	static int setup_netfront(struct xenbus_device dev, struct netfront_info info)
1329	{
1330	struct xen_netif_tx_sring *txs;
1331	struct xen_netif_rx_sring *rxs;
1332	int err;
1333	struct net_device *netdev = info->netdev;
1334
1335	info->tx_ring_ref = GRANT_INVALID_REF;
1336	info->rx_ring_ref = GRANT_INVALID_REF;
1337	info->rx.sring = NULL;
1338	info->tx.sring = NULL;
1339	netdev->irq = 0;
1340
1341	err = xen_net_read_mac(dev, netdev->dev_addr);
1342	if (err) {
1343	xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
1344	goto fail;
1345	}
1346
1347	txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO \| __GFP_HIGH);
1348	if (!txs) {
1349	err = -ENOMEM;
1350	xenbus_dev_fatal(dev, err, "allocating tx ring page");
1351	goto fail;
1352	}
1353	SHARED_RING_INIT(txs);
1354	FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE);
1355
1356	err = xenbus_grant_ring(dev, virt_to_mfn(txs));
1357	if (err < 0) {
1358	free_page((unsigned long)txs);
1359	goto fail;
1360	}
1361
1362	info->tx_ring_ref = err;
1363	rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO \| __GFP_HIGH);
1364	if (!rxs) {
1365	err = -ENOMEM;
1366	xenbus_dev_fatal(dev, err, "allocating rx ring page");
1367	goto fail;
1368	}
1369	SHARED_RING_INIT(rxs);
1370	FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE);
1371
1372	err = xenbus_grant_ring(dev, virt_to_mfn(rxs));
1373	if (err < 0) {
1374	free_page((unsigned long)rxs);
1375	goto fail;
1376	}
1377	info->rx_ring_ref = err;
1378
1379	err = xenbus_alloc_evtchn(dev, &info->evtchn);
1380	if (err)
1381	goto fail;
1382
1383	err = bind_evtchn_to_irqhandler(info->evtchn, xennet_interrupt,
1384	IRQF_SAMPLE_RANDOM, netdev->name,
1385	netdev);
1386	if (err < 0)
1387	goto fail;
1388	netdev->irq = err;
1389	return 0;
1390
1391	fail:
1392	return err;
1393	}
1394
1395	/* Common code used when first setting up, and when resuming. */
1396	static int talk_to_backend(struct xenbus_device *dev,
1397	struct netfront_info *info)
1398	{
1399	const char *message;
1400	struct xenbus_transaction xbt;
1401	int err;
1402
1403	/* Create shared ring, alloc event channel. */
1404	err = setup_netfront(dev, info);
1405	if (err)
1406	goto out;
1407
1408	again:
1409	err = xenbus_transaction_start(&xbt);
1410	if (err) {
1411	xenbus_dev_fatal(dev, err, "starting transaction");
1412	goto destroy_ring;
1413	}
1414
1415	err = xenbus_printf(xbt, dev->nodename, "tx-ring-ref", "%u",
1416	info->tx_ring_ref);
1417	if (err) {
1418	message = "writing tx ring-ref";
1419	goto abort_transaction;
1420	}
1421	err = xenbus_printf(xbt, dev->nodename, "rx-ring-ref", "%u",
1422	info->rx_ring_ref);
1423	if (err) {
1424	message = "writing rx ring-ref";
1425	goto abort_transaction;
1426	}
1427	err = xenbus_printf(xbt, dev->nodename,
1428	"event-channel", "%u", info->evtchn);
1429	if (err) {
1430	message = "writing event-channel";
1431	goto abort_transaction;
1432	}
1433
1434	err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
1435	1);
1436	if (err) {
1437	message = "writing request-rx-copy";
1438	goto abort_transaction;
1439	}
1440
1441	err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1);
1442	if (err) {
1443	message = "writing feature-rx-notify";
1444	goto abort_transaction;
1445	}
1446
1447	err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1);
1448	if (err) {
1449	message = "writing feature-sg";
1450	goto abort_transaction;
1451	}
1452
1453	err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1);
1454	if (err) {
1455	message = "writing feature-gso-tcpv4";
1456	goto abort_transaction;
1457	}
1458
1459	err = xenbus_transaction_end(xbt, 0);
1460	if (err) {
1461	if (err == -EAGAIN)
1462	goto again;
1463	xenbus_dev_fatal(dev, err, "completing transaction");
1464	goto destroy_ring;
1465	}
1466
1467	return 0;
1468
1469	abort_transaction:
1470	xenbus_transaction_end(xbt, 1);
1471	xenbus_dev_fatal(dev, err, "%s", message);
1472	destroy_ring:
1473	xennet_disconnect_backend(info);
1474	out:
1475	return err;
1476	}
1477
1478	static int xennet_set_sg(struct net_device *dev, u32 data)
1479	{
1480	if (data) {
1481	struct netfront_info *np = netdev_priv(dev);
1482	int val;
1483
1484	if (xenbus_scanf(XBT_NIL, np->xbdev->otherend, "feature-sg",
1485	"%d", &val) < 0)
1486	val = 0;
1487	if (!val)
1488	return -ENOSYS;
1489	} else if (dev->mtu > ETH_DATA_LEN)
1490	dev->mtu = ETH_DATA_LEN;
1491
1492	return ethtool_op_set_sg(dev, data);
1493	}
1494
1495	static int xennet_set_tso(struct net_device *dev, u32 data)
1496	{
1497	if (data) {
1498	struct netfront_info *np = netdev_priv(dev);
1499	int val;
1500
1501	if (xenbus_scanf(XBT_NIL, np->xbdev->otherend,
1502	"feature-gso-tcpv4", "%d", &val) < 0)
1503	val = 0;
1504	if (!val)
1505	return -ENOSYS;
1506	}
1507
1508	return ethtool_op_set_tso(dev, data);
1509	}
1510
1511	static void xennet_set_features(struct net_device *dev)
1512	{
1513	/* Turn off all GSO bits except ROBUST. */
1514	dev->features &= ~NETIF_F_GSO_MASK;
1515	dev->features \|= NETIF_F_GSO_ROBUST;
1516	xennet_set_sg(dev, 0);
1517
1518	/* We need checksum offload to enable scatter/gather and TSO. */
1519	if (!(dev->features & NETIF_F_IP_CSUM))
1520	return;
1521
1522	if (!xennet_set_sg(dev, 1))
1523	xennet_set_tso(dev, 1);
1524	}
1525
1526	static int xennet_connect(struct net_device *dev)
1527	{
1528	struct netfront_info *np = netdev_priv(dev);
1529	int i, requeue_idx, err;
1530	struct sk_buff *skb;
1531	grant_ref_t ref;
1532	struct xen_netif_rx_request *req;
1533	unsigned int feature_rx_copy;
1534
1535	err = xenbus_scanf(XBT_NIL, np->xbdev->otherend,
1536	"feature-rx-copy", "%u", &feature_rx_copy);
1537	if (err != 1)
1538	feature_rx_copy = 0;
1539
1540	if (!feature_rx_copy) {
1541	dev_info(&dev->dev,
1542	"backend does not support copying receive path\n");
1543	return -ENODEV;
1544	}
1545
1546	err = talk_to_backend(np->xbdev, np);
1547	if (err)
1548	return err;
1549
1550	xennet_set_features(dev);
1551
1552	spin_lock_bh(&np->rx_lock);
1553	spin_lock_irq(&np->tx_lock);
1554
1555	/* Step 1: Discard all pending TX packet fragments. */
1556	xennet_release_tx_bufs(np);
1557
1558	/* Step 2: Rebuild the RX buffer freelist and the RX ring itself. */
1559	for (requeue_idx = 0, i = 0; i < NET_RX_RING_SIZE; i++) {
1560	if (!np->rx_skbs[i])
1561	continue;
1562
1563	skb = np->rx_skbs[requeue_idx] = xennet_get_rx_skb(np, i);
1564	ref = np->grant_rx_ref[requeue_idx] = xennet_get_rx_ref(np, i);
1565	req = RING_GET_REQUEST(&np->rx, requeue_idx);
1566
1567	gnttab_grant_foreign_access_ref(
1568	ref, np->xbdev->otherend_id,
1569	pfn_to_mfn(page_to_pfn(skb_shinfo(skb)->
1570	frags->page)),
1571	0);
1572	req->gref = ref;
1573	req->id = requeue_idx;
1574
1575	requeue_idx++;
1576	}
1577
1578	np->rx.req_prod_pvt = requeue_idx;
1579
1580	/*
1581	* Step 3: All public and private state should now be sane. Get
1582	* ready to start sending and receiving packets and give the driver
1583	* domain a kick because we've probably just requeued some
1584	* packets.
1585	*/
1586	netif_carrier_on(np->netdev);
1587	notify_remote_via_irq(np->netdev->irq);
1588	xennet_tx_buf_gc(dev);
1589	xennet_alloc_rx_buffers(dev);
1590
1591	spin_unlock_irq(&np->tx_lock);
1592	spin_unlock_bh(&np->rx_lock);
1593
1594	return 0;
1595	}
1596
1597	/**
1598	* Callback received when the backend's state changes.
1599	*/
1600	static void backend_changed(struct xenbus_device *dev,
1601	enum xenbus_state backend_state)
1602	{
1603	struct netfront_info *np = dev_get_drvdata(&dev->dev);
1604	struct net_device *netdev = np->netdev;
1605
1606	dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));
1607
1608	switch (backend_state) {
1609	case XenbusStateInitialising:
1610	case XenbusStateInitialised:
1611	case XenbusStateConnected:
1612	case XenbusStateUnknown:
1613	case XenbusStateClosed:
1614	break;
1615
1616	case XenbusStateInitWait:
1617	if (dev->state != XenbusStateInitialising)
1618	break;
1619	if (xennet_connect(netdev) != 0)
1620	break;
1621	xenbus_switch_state(dev, XenbusStateConnected);
1622	break;
1623
1624	case XenbusStateClosing:
1625	xenbus_frontend_closed(dev);
1626	break;
1627	}
1628	}
1629
1630	static struct ethtool_ops xennet_ethtool_ops =
1631	{
1632	.set_tx_csum = ethtool_op_set_tx_csum,
1633	.set_sg = xennet_set_sg,
1634	.set_tso = xennet_set_tso,
1635	.get_link = ethtool_op_get_link,
1636	};
1637
1638	#ifdef CONFIG_SYSFS
1639	static ssize_t show_rxbuf_min(struct device *dev,
1640	struct device_attribute attr, char buf)
1641	{
1642	struct net_device *netdev = to_net_dev(dev);
1643	struct netfront_info *info = netdev_priv(netdev);
1644
1645	return sprintf(buf, "%u\n", info->rx_min_target);
1646	}
1647
1648	static ssize_t store_rxbuf_min(struct device *dev,
1649	struct device_attribute *attr,
1650	const char *buf, size_t len)
1651	{
1652	struct net_device *netdev = to_net_dev(dev);
1653	struct netfront_info *np = netdev_priv(netdev);
1654	char *endp;
1655	unsigned long target;
1656
1657	if (!capable(CAP_NET_ADMIN))
1658	return -EPERM;
1659
1660	target = simple_strtoul(buf, &endp, 0);
1661	if (endp == buf)
1662	return -EBADMSG;
1663
1664	if (target < RX_MIN_TARGET)
1665	target = RX_MIN_TARGET;
1666	if (target > RX_MAX_TARGET)
1667	target = RX_MAX_TARGET;
1668
1669	spin_lock_bh(&np->rx_lock);
1670	if (target > np->rx_max_target)
1671	np->rx_max_target = target;
1672	np->rx_min_target = target;
1673	if (target > np->rx_target)
1674	np->rx_target = target;
1675
1676	xennet_alloc_rx_buffers(netdev);
1677
1678	spin_unlock_bh(&np->rx_lock);
1679	return len;
1680	}
1681
1682	static ssize_t show_rxbuf_max(struct device *dev,
1683	struct device_attribute attr, char buf)
1684	{
1685	struct net_device *netdev = to_net_dev(dev);
1686	struct netfront_info *info = netdev_priv(netdev);
1687
1688	return sprintf(buf, "%u\n", info->rx_max_target);
1689	}
1690
1691	static ssize_t store_rxbuf_max(struct device *dev,
1692	struct device_attribute *attr,
1693	const char *buf, size_t len)
1694	{
1695	struct net_device *netdev = to_net_dev(dev);
1696	struct netfront_info *np = netdev_priv(netdev);
1697	char *endp;
1698	unsigned long target;
1699
1700	if (!capable(CAP_NET_ADMIN))
1701	return -EPERM;
1702
1703	target = simple_strtoul(buf, &endp, 0);
1704	if (endp == buf)
1705	return -EBADMSG;
1706
1707	if (target < RX_MIN_TARGET)
1708	target = RX_MIN_TARGET;
1709	if (target > RX_MAX_TARGET)
1710	target = RX_MAX_TARGET;
1711
1712	spin_lock_bh(&np->rx_lock);
1713	if (target < np->rx_min_target)
1714	np->rx_min_target = target;
1715	np->rx_max_target = target;
1716	if (target < np->rx_target)
1717	np->rx_target = target;
1718
1719	xennet_alloc_rx_buffers(netdev);
1720
1721	spin_unlock_bh(&np->rx_lock);
1722	return len;
1723	}
1724
1725	static ssize_t show_rxbuf_cur(struct device *dev,
1726	struct device_attribute attr, char buf)
1727	{
1728	struct net_device *netdev = to_net_dev(dev);
1729	struct netfront_info *info = netdev_priv(netdev);
1730
1731	return sprintf(buf, "%u\n", info->rx_target);
1732	}
1733
1734	static struct device_attribute xennet_attrs[] = {
1735	__ATTR(rxbuf_min, S_IRUGO\|S_IWUSR, show_rxbuf_min, store_rxbuf_min),
1736	__ATTR(rxbuf_max, S_IRUGO\|S_IWUSR, show_rxbuf_max, store_rxbuf_max),
1737	__ATTR(rxbuf_cur, S_IRUGO, show_rxbuf_cur, NULL),
1738	};
1739
1740	static int xennet_sysfs_addif(struct net_device *netdev)
1741	{
1742	int i;
1743	int err;
1744
1745	for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++) {
1746	err = device_create_file(&netdev->dev,
1747	&xennet_attrs[i]);
1748	if (err)
1749	goto fail;
1750	}
1751	return 0;
1752
1753	fail:
1754	while (--i >= 0)
1755	device_remove_file(&netdev->dev, &xennet_attrs[i]);
1756	return err;
1757	}
1758
1759	static void xennet_sysfs_delif(struct net_device *netdev)
1760	{
1761	int i;
1762
1763	for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++)
1764	device_remove_file(&netdev->dev, &xennet_attrs[i]);
1765	}
1766
1767	#endif /* CONFIG_SYSFS */
1768
1769	static struct xenbus_device_id netfront_ids[] = {
1770	{ "vif" },
1771	{ "" }
1772	};
1773
1774
1775	static int __devexit xennet_remove(struct xenbus_device *dev)
1776	{
1777	struct netfront_info *info = dev_get_drvdata(&dev->dev);
1778
1779	dev_dbg(&dev->dev, "%s\n", dev->nodename);
1780
1781	unregister_netdev(info->netdev);
1782
1783	xennet_disconnect_backend(info);
1784
1785	del_timer_sync(&info->rx_refill_timer);
1786
1787	xennet_sysfs_delif(info->netdev);
1788
1789	free_netdev(info->netdev);
1790
1791	return 0;
1792	}
1793
1794	static struct xenbus_driver netfront_driver = {
1795	.name = "vif",
1796	.owner = THIS_MODULE,
1797	.ids = netfront_ids,
1798	.probe = netfront_probe,
1799	.remove = __devexit_p(xennet_remove),
1800	.resume = netfront_resume,
1801	.otherend_changed = backend_changed,
1802	};
1803
1804	static int __init netif_init(void)
1805	{
1806	if (!xen_domain())
1807	return -ENODEV;
1808
1809	if (xen_initial_domain())
1810	return 0;
1811
1812	printk(KERN_INFO "Initialising Xen virtual ethernet driver.\n");
1813
1814	return xenbus_register_frontend(&netfront_driver);
1815	}
1816	module_init(netif_init);
1817
1818
1819	static void __exit netif_exit(void)
1820	{
1821	if (xen_initial_domain())
1822	return;
1823
1824	xenbus_unregister_driver(&netfront_driver);
1825	}
1826	module_exit(netif_exit);
1827
1828	MODULE_DESCRIPTION("Xen virtual network device frontend");
1829	MODULE_LICENSE("GPL");
1830	MODULE_ALIAS("xen:vif");
1831	MODULE_ALIAS("xennet");
1832

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