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	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33
34	#include <linux/module.h>
35	#include <linux/kernel.h>
36	#include <linux/netdevice.h>
37	#include <linux/etherdevice.h>
38	#include <linux/skbuff.h>
39	#include <linux/ethtool.h>
40	#include <linux/if_ether.h>
41	#include <net/tcp.h>
42	#include <linux/udp.h>
43	#include <linux/moduleparam.h>
44	#include <linux/mm.h>
45	#include <linux/slab.h>
46	#include <net/ip.h>
47	#include <linux/bpf.h>
48	#include <net/page_pool/types.h>
49	#include <linux/bpf_trace.h>
50
51	#include <xen/xen.h>
52	#include <xen/xenbus.h>
53	#include <xen/events.h>
54	#include <xen/page.h>
55	#include <xen/platform_pci.h>
56	#include <xen/grant_table.h>
57
58	#include <xen/interface/io/netif.h>
59	#include <xen/interface/memory.h>
60	#include <xen/interface/grant_table.h>
61
62	/* Module parameters */
63	#define MAX_QUEUES_DEFAULT 8
64	static unsigned int xennet_max_queues;
65	module_param_named(max_queues, xennet_max_queues, uint, 0644);
66	MODULE_PARM_DESC(max_queues,
67	"Maximum number of queues per virtual interface");
68
69	static bool __read_mostly xennet_trusted = true;
70	module_param_named(trusted, xennet_trusted, bool, 0644);
71	MODULE_PARM_DESC(trusted, "Is the backend trusted");
72
73	#define XENNET_TIMEOUT (5 * HZ)
74
75	static const struct ethtool_ops xennet_ethtool_ops;
76
77	struct netfront_cb {
78	int pull_to;
79	};
80
81	#define NETFRONT_SKB_CB(skb) ((struct netfront_cb *)((skb)->cb))
82
83	#define RX_COPY_THRESHOLD 256
84
85	#define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, XEN_PAGE_SIZE)
86	#define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, XEN_PAGE_SIZE)
87
88	/* Minimum number of Rx slots (includes slot for GSO metadata). */
89	#define NET_RX_SLOTS_MIN (XEN_NETIF_NR_SLOTS_MIN + 1)
90
91	/* Queue name is interface name with "-qNNN" appended */
92	#define QUEUE_NAME_SIZE (IFNAMSIZ + 6)
93
94	/* IRQ name is queue name with "-tx" or "-rx" appended */
95	#define IRQ_NAME_SIZE (QUEUE_NAME_SIZE + 3)
96
97	static DECLARE_WAIT_QUEUE_HEAD(module_wq);
98
99	struct netfront_stats {
100	u64 packets;
101	u64 bytes;
102	struct u64_stats_sync syncp;
103	};
104
105	struct netfront_info;
106
107	struct netfront_queue {
108	unsigned int id; /* Queue ID, 0-based */
109	char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
110	struct netfront_info *info;
111
112	struct bpf_prog __rcu *xdp_prog;
113
114	struct napi_struct napi;
115
116	/* Split event channels support, tx_* == rx_* when using
117	* single event channel.
118	*/
119	unsigned int tx_evtchn, rx_evtchn;
120	unsigned int tx_irq, rx_irq;
121	/* Only used when split event channels support is enabled */
122	char tx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-tx */
123	char rx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-rx */
124
125	spinlock_t tx_lock;
126	struct xen_netif_tx_front_ring tx;
127	int tx_ring_ref;
128
129	/*
130	* {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
131	* are linked from tx_skb_freelist through tx_link.
132	*/
133	struct sk_buff *tx_skbs[NET_TX_RING_SIZE];
134	unsigned short tx_link[NET_TX_RING_SIZE];
135	#define TX_LINK_NONE 0xffff
136	#define TX_PENDING 0xfffe
137	grant_ref_t gref_tx_head;
138	grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
139	struct page *grant_tx_page[NET_TX_RING_SIZE];
140	unsigned tx_skb_freelist;
141	unsigned int tx_pend_queue;
142
143	spinlock_t rx_lock ____cacheline_aligned_in_smp;
144	struct xen_netif_rx_front_ring rx;
145	int rx_ring_ref;
146
147	struct timer_list rx_refill_timer;
148
149	struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
150	grant_ref_t gref_rx_head;
151	grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
152
153	unsigned int rx_rsp_unconsumed;
154	spinlock_t rx_cons_lock;
155
156	struct page_pool *page_pool;
157	struct xdp_rxq_info xdp_rxq;
158	};
159
160	struct netfront_info {
161	struct list_head list;
162	struct net_device *netdev;
163
164	struct xenbus_device *xbdev;
165
166	/* Multi-queue support */
167	struct netfront_queue *queues;
168
169	/* Statistics */
170	struct netfront_stats __percpu *rx_stats;
171	struct netfront_stats __percpu *tx_stats;
172
173	/* XDP state */
174	bool netback_has_xdp_headroom;
175	bool netfront_xdp_enabled;
176
177	/* Is device behaving sane? */
178	bool broken;
179
180	/* Should skbs be bounced into a zeroed buffer? */
181	bool bounce;
182
183	atomic_t rx_gso_checksum_fixup;
184	};
185
186	struct netfront_rx_info {
187	struct xen_netif_rx_response rx;
188	struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
189	};
190
191	/*
192	* Access macros for acquiring freeing slots in tx_skbs[].
193	*/
194
195	static void add_id_to_list(unsigned *head, unsigned short *list,
196	unsigned short id)
197	{
198	list[id] = *head;
199	*head = id;
200	}
201
202	static unsigned short get_id_from_list(unsigned *head, unsigned short *list)
203	{
204	unsigned int id = *head;
205
206	if (id != TX_LINK_NONE) {
207	*head = list[id];
208	list[id] = TX_LINK_NONE;
209	}
210	return id;
211	}
212
213	static int xennet_rxidx(RING_IDX idx)
214	{
215	return idx & (NET_RX_RING_SIZE - 1);
216	}
217
218	static struct sk_buff *xennet_get_rx_skb(struct netfront_queue *queue,
219	RING_IDX ri)
220	{
221	int i = xennet_rxidx(idx: ri);
222	struct sk_buff *skb = queue->rx_skbs[i];
223	queue->rx_skbs[i] = NULL;
224	return skb;
225	}
226
227	static grant_ref_t xennet_get_rx_ref(struct netfront_queue *queue,
228	RING_IDX ri)
229	{
230	int i = xennet_rxidx(idx: ri);
231	grant_ref_t ref = queue->grant_rx_ref[i];
232	queue->grant_rx_ref[i] = INVALID_GRANT_REF;
233	return ref;
234	}
235
236	#ifdef CONFIG_SYSFS
237	static const struct attribute_group xennet_dev_group;
238	#endif
239
240	static bool xennet_can_sg(struct net_device *dev)
241	{
242	return dev->features & NETIF_F_SG;
243	}
244
245
246	static void rx_refill_timeout(struct timer_list *t)
247	{
248	struct netfront_queue *queue = from_timer(queue, t, rx_refill_timer);
249	napi_schedule(n: &queue->napi);
250	}
251
252	static int netfront_tx_slot_available(struct netfront_queue *queue)
253	{
254	return (queue->tx.req_prod_pvt - queue->tx.rsp_cons) <
255	(NET_TX_RING_SIZE - XEN_NETIF_NR_SLOTS_MIN - 1);
256	}
257
258	static void xennet_maybe_wake_tx(struct netfront_queue *queue)
259	{
260	struct net_device *dev = queue->info->netdev;
261	struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, index: queue->id);
262
263	if (unlikely(netif_tx_queue_stopped(dev_queue)) &&
264	netfront_tx_slot_available(queue) &&
265	likely(netif_running(dev)))
266	netif_tx_wake_queue(dev_queue: netdev_get_tx_queue(dev, index: queue->id));
267	}
268
269
270	static struct sk_buff *xennet_alloc_one_rx_buffer(struct netfront_queue *queue)
271	{
272	struct sk_buff *skb;
273	struct page *page;
274
275	skb = __netdev_alloc_skb(dev: queue->info->netdev,
276	RX_COPY_THRESHOLD + NET_IP_ALIGN,
277	GFP_ATOMIC | __GFP_NOWARN);
278	if (unlikely(!skb))
279	return NULL;
280
281	page = page_pool_alloc_pages(pool: queue->page_pool,
282	GFP_ATOMIC | __GFP_NOWARN | __GFP_ZERO);
283	if (unlikely(!page)) {
284	kfree_skb(skb);
285	return NULL;
286	}
287	skb_add_rx_frag(skb, i: 0, page, off: 0, size: 0, PAGE_SIZE);
288	skb_mark_for_recycle(skb);
289
290	/* Align ip header to a 16 bytes boundary */
291	skb_reserve(skb, NET_IP_ALIGN);
292	skb->dev = queue->info->netdev;
293
294	return skb;
295	}
296
297
298	static void xennet_alloc_rx_buffers(struct netfront_queue *queue)
299	{
300	RING_IDX req_prod = queue->rx.req_prod_pvt;
301	int notify;
302	int err = 0;
303
304	if (unlikely(!netif_carrier_ok(queue->info->netdev)))
305	return;
306
307	for (req_prod = queue->rx.req_prod_pvt;
308	req_prod - queue->rx.rsp_cons < NET_RX_RING_SIZE;
309	req_prod++) {
310	struct sk_buff *skb;
311	unsigned short id;
312	grant_ref_t ref;
313	struct page *page;
314	struct xen_netif_rx_request *req;
315
316	skb = xennet_alloc_one_rx_buffer(queue);
317	if (!skb) {
318	err = -ENOMEM;
319	break;
320	}
321
322	id = xennet_rxidx(idx: req_prod);
323
324	BUG_ON(queue->rx_skbs[id]);
325	queue->rx_skbs[id] = skb;
326
327	ref = gnttab_claim_grant_reference(pprivate_head: &queue->gref_rx_head);
328	WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref));
329	queue->grant_rx_ref[id] = ref;
330
331	page = skb_frag_page(frag: &skb_shinfo(skb)->frags[0]);
332
333	req = RING_GET_REQUEST(&queue->rx, req_prod);
334	gnttab_page_grant_foreign_access_ref_one(ref,
335	domid: queue->info->xbdev->otherend_id,
336	page,
337	readonly: 0);
338	req->id = id;
339	req->gref = ref;
340	}
341
342	queue->rx.req_prod_pvt = req_prod;
343
344	/* Try again later if there are not enough requests or skb allocation
345	* failed.
346	* Enough requests is quantified as the sum of newly created slots and
347	* the unconsumed slots at the backend.
348	*/
349	if (req_prod - queue->rx.rsp_cons < NET_RX_SLOTS_MIN ||
350	unlikely(err)) {
351	mod_timer(timer: &queue->rx_refill_timer, expires: jiffies + (HZ/10));
352	return;
353	}
354
355	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->rx, notify);
356	if (notify)
357	notify_remote_via_irq(irq: queue->rx_irq);
358	}
359
360	static int xennet_open(struct net_device *dev)
361	{
362	struct netfront_info *np = netdev_priv(dev);
363	unsigned int num_queues = dev->real_num_tx_queues;
364	unsigned int i = 0;
365	struct netfront_queue *queue = NULL;
366
367	if (!np->queues || np->broken)
368	return -ENODEV;
369
370	for (i = 0; i < num_queues; ++i) {
371	queue = &np->queues[i];
372	napi_enable(n: &queue->napi);
373
374	spin_lock_bh(lock: &queue->rx_lock);
375	if (netif_carrier_ok(dev)) {
376	xennet_alloc_rx_buffers(queue);
377	queue->rx.sring->rsp_event = queue->rx.rsp_cons + 1;
378	if (RING_HAS_UNCONSUMED_RESPONSES(&queue->rx))
379	napi_schedule(n: &queue->napi);
380	}
381	spin_unlock_bh(lock: &queue->rx_lock);
382	}
383
384	netif_tx_start_all_queues(dev);
385
386	return 0;
387	}
388
389	static bool xennet_tx_buf_gc(struct netfront_queue *queue)
390	{
391	RING_IDX cons, prod;
392	unsigned short id;
393	struct sk_buff *skb;
394	bool more_to_do;
395	bool work_done = false;
396	const struct device *dev = &queue->info->netdev->dev;
397
398	BUG_ON(!netif_carrier_ok(queue->info->netdev));
399
400	do {
401	prod = queue->tx.sring->rsp_prod;
402	if (RING_RESPONSE_PROD_OVERFLOW(&queue->tx, prod)) {
403	dev_alert(dev, "Illegal number of responses %u\n",
404	prod - queue->tx.rsp_cons);
405	goto err;
406	}
407	rmb(); /* Ensure we see responses up to 'rp'. */
408
409	for (cons = queue->tx.rsp_cons; cons != prod; cons++) {
410	struct xen_netif_tx_response txrsp;
411
412	work_done = true;
413
414	RING_COPY_RESPONSE(&queue->tx, cons, &txrsp);
415	if (txrsp.status == XEN_NETIF_RSP_NULL)
416	continue;
417
418	id = txrsp.id;
419	if (id >= RING_SIZE(&queue->tx)) {
420	dev_alert(dev,
421	"Response has incorrect id (%u)\n",
422	id);
423	goto err;
424	}
425	if (queue->tx_link[id] != TX_PENDING) {
426	dev_alert(dev,
427	"Response for inactive request\n");
428	goto err;
429	}
430
431	queue->tx_link[id] = TX_LINK_NONE;
432	skb = queue->tx_skbs[id];
433	queue->tx_skbs[id] = NULL;
434	if (unlikely(!gnttab_end_foreign_access_ref(
435	queue->grant_tx_ref[id]))) {
436	dev_alert(dev,
437	"Grant still in use by backend domain\n");
438	goto err;
439	}
440	gnttab_release_grant_reference(
441	private_head: &queue->gref_tx_head, release: queue->grant_tx_ref[id]);
442	queue->grant_tx_ref[id] = INVALID_GRANT_REF;
443	queue->grant_tx_page[id] = NULL;
444	add_id_to_list(head: &queue->tx_skb_freelist, list: queue->tx_link, id);
445	dev_kfree_skb_irq(skb);
446	}
447
448	queue->tx.rsp_cons = prod;
449
450	RING_FINAL_CHECK_FOR_RESPONSES(&queue->tx, more_to_do);
451	} while (more_to_do);
452
453	xennet_maybe_wake_tx(queue);
454
455	return work_done;
456
457	err:
458	queue->info->broken = true;
459	dev_alert(dev, "Disabled for further use\n");
460
461	return work_done;
462	}
463
464	struct xennet_gnttab_make_txreq {
465	struct netfront_queue *queue;
466	struct sk_buff *skb;
467	struct page *page;
468	struct xen_netif_tx_request *tx; /* Last request on ring page */
469	struct xen_netif_tx_request tx_local; /* Last request local copy*/
470	unsigned int size;
471	};
472
473	static void xennet_tx_setup_grant(unsigned long gfn, unsigned int offset,
474	unsigned int len, void *data)
475	{
476	struct xennet_gnttab_make_txreq *info = data;
477	unsigned int id;
478	struct xen_netif_tx_request *tx;
479	grant_ref_t ref;
480	/* convenient aliases */
481	struct page *page = info->page;
482	struct netfront_queue *queue = info->queue;
483	struct sk_buff *skb = info->skb;
484
485	id = get_id_from_list(head: &queue->tx_skb_freelist, list: queue->tx_link);
486	tx = RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
487	ref = gnttab_claim_grant_reference(pprivate_head: &queue->gref_tx_head);
488	WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref));
489
490	gnttab_grant_foreign_access_ref(ref, domid: queue->info->xbdev->otherend_id,
491	frame: gfn, GNTMAP_readonly);
492
493	queue->tx_skbs[id] = skb;
494	queue->grant_tx_page[id] = page;
495	queue->grant_tx_ref[id] = ref;
496
497	info->tx_local.id = id;
498	info->tx_local.gref = ref;
499	info->tx_local.offset = offset;
500	info->tx_local.size = len;
501	info->tx_local.flags = 0;
502
503	*tx = info->tx_local;
504
505	/*
506	* Put the request in the pending queue, it will be set to be pending
507	* when the producer index is about to be raised.
508	*/
509	add_id_to_list(head: &queue->tx_pend_queue, list: queue->tx_link, id);
510
511	info->tx = tx;
512	info->size += info->tx_local.size;
513	}
514
515	static struct xen_netif_tx_request *xennet_make_first_txreq(
516	struct xennet_gnttab_make_txreq *info,
517	unsigned int offset, unsigned int len)
518	{
519	info->size = 0;
520
521	gnttab_for_one_grant(page: info->page, offset, len, fn: xennet_tx_setup_grant, data: info);
522
523	return info->tx;
524	}
525
526	static void xennet_make_one_txreq(unsigned long gfn, unsigned int offset,
527	unsigned int len, void *data)
528	{
529	struct xennet_gnttab_make_txreq *info = data;
530
531	info->tx->flags |= XEN_NETTXF_more_data;
532	skb_get(skb: info->skb);
533	xennet_tx_setup_grant(gfn, offset, len, data);
534	}
535
536	static void xennet_make_txreqs(
537	struct xennet_gnttab_make_txreq *info,
538	struct page *page,
539	unsigned int offset, unsigned int len)
540	{
541	/* Skip unused frames from start of page */
542	page += offset >> PAGE_SHIFT;
543	offset &= ~PAGE_MASK;
544
545	while (len) {
546	info->page = page;
547	info->size = 0;
548
549	gnttab_foreach_grant_in_range(page, offset, len,
550	fn: xennet_make_one_txreq,
551	data: info);
552
553	page++;
554	offset = 0;
555	len -= info->size;
556	}
557	}
558
559	/*
560	* Count how many ring slots are required to send this skb. Each frag
561	* might be a compound page.
562	*/
563	static int xennet_count_skb_slots(struct sk_buff *skb)
564	{
565	int i, frags = skb_shinfo(skb)->nr_frags;
566	int slots;
567
568	slots = gnttab_count_grant(offset_in_page(skb->data),
569	len: skb_headlen(skb));
570
571	for (i = 0; i < frags; i++) {
572	skb_frag_t *frag = skb_shinfo(skb)->frags + i;
573	unsigned long size = skb_frag_size(frag);
574	unsigned long offset = skb_frag_off(frag);
575
576	/* Skip unused frames from start of page */
577	offset &= ~PAGE_MASK;
578
579	slots += gnttab_count_grant(start: offset, len: size);
580	}
581
582	return slots;
583	}
584
585	static u16 xennet_select_queue(struct net_device *dev, struct sk_buff *skb,
586	struct net_device *sb_dev)
587	{
588	unsigned int num_queues = dev->real_num_tx_queues;
589	u32 hash;
590	u16 queue_idx;
591
592	/* First, check if there is only one queue */
593	if (num_queues == 1) {
594	queue_idx = 0;
595	} else {
596	hash = skb_get_hash(skb);
597	queue_idx = hash % num_queues;
598	}
599
600	return queue_idx;
601	}
602
603	static void xennet_mark_tx_pending(struct netfront_queue *queue)
604	{
605	unsigned int i;
606
607	while ((i = get_id_from_list(head: &queue->tx_pend_queue, list: queue->tx_link)) !=
608	TX_LINK_NONE)
609	queue->tx_link[i] = TX_PENDING;
610	}
611
612	static int xennet_xdp_xmit_one(struct net_device *dev,
613	struct netfront_queue *queue,
614	struct xdp_frame *xdpf)
615	{
616	struct netfront_info *np = netdev_priv(dev);
617	struct netfront_stats *tx_stats = this_cpu_ptr(np->tx_stats);
618	struct xennet_gnttab_make_txreq info = {
619	.queue = queue,
620	.skb = NULL,
621	.page = virt_to_page(xdpf->data),
622	};
623	int notify;
624
625	xennet_make_first_txreq(info: &info,
626	offset_in_page(xdpf->data),
627	len: xdpf->len);
628
629	xennet_mark_tx_pending(queue);
630
631	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
632	if (notify)
633	notify_remote_via_irq(irq: queue->tx_irq);
634
635	u64_stats_update_begin(syncp: &tx_stats->syncp);
636	tx_stats->bytes += xdpf->len;
637	tx_stats->packets++;
638	u64_stats_update_end(syncp: &tx_stats->syncp);
639
640	xennet_tx_buf_gc(queue);
641
642	return 0;
643	}
644
645	static int xennet_xdp_xmit(struct net_device *dev, int n,
646	struct xdp_frame **frames, u32 flags)
647	{
648	unsigned int num_queues = dev->real_num_tx_queues;
649	struct netfront_info *np = netdev_priv(dev);
650	struct netfront_queue *queue = NULL;
651	unsigned long irq_flags;
652	int nxmit = 0;
653	int i;
654
655	if (unlikely(np->broken))
656	return -ENODEV;
657	if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
658	return -EINVAL;
659
660	queue = &np->queues[smp_processor_id() % num_queues];
661
662	spin_lock_irqsave(&queue->tx_lock, irq_flags);
663	for (i = 0; i < n; i++) {
664	struct xdp_frame *xdpf = frames[i];
665
666	if (!xdpf)
667	continue;
668	if (xennet_xdp_xmit_one(dev, queue, xdpf))
669	break;
670	nxmit++;
671	}
672	spin_unlock_irqrestore(lock: &queue->tx_lock, flags: irq_flags);
673
674	return nxmit;
675	}
676
677	static struct sk_buff *bounce_skb(const struct sk_buff *skb)
678	{
679	unsigned int headerlen = skb_headroom(skb);
680	/* Align size to allocate full pages and avoid contiguous data leaks */
681	unsigned int size = ALIGN(skb_end_offset(skb) + skb->data_len,
682	XEN_PAGE_SIZE);
683	struct sk_buff *n = alloc_skb(size, GFP_ATOMIC | __GFP_ZERO);
684
685	if (!n)
686	return NULL;
687
688	if (!IS_ALIGNED((uintptr_t)n->head, XEN_PAGE_SIZE)) {
689	WARN_ONCE(1, "misaligned skb allocated\n");
690	kfree_skb(skb: n);
691	return NULL;
692	}
693
694	/* Set the data pointer */
695	skb_reserve(skb: n, len: headerlen);
696	/* Set the tail pointer and length */
697	skb_put(skb: n, len: skb->len);
698
699	BUG_ON(skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len));
700
701	skb_copy_header(new: n, old: skb);
702	return n;
703	}
704
705	#define MAX_XEN_SKB_FRAGS (65536 / XEN_PAGE_SIZE + 1)
706
707	static netdev_tx_t xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
708	{
709	struct netfront_info *np = netdev_priv(dev);
710	struct netfront_stats *tx_stats = this_cpu_ptr(np->tx_stats);
711	struct xen_netif_tx_request *first_tx;
712	unsigned int i;
713	int notify;
714	int slots;
715	struct page *page;
716	unsigned int offset;
717	unsigned int len;
718	unsigned long flags;
719	struct netfront_queue *queue = NULL;
720	struct xennet_gnttab_make_txreq info = { };
721	unsigned int num_queues = dev->real_num_tx_queues;
722	u16 queue_index;
723	struct sk_buff *nskb;
724
725	/* Drop the packet if no queues are set up */
726	if (num_queues < 1)
727	goto drop;
728	if (unlikely(np->broken))
729	goto drop;
730	/* Determine which queue to transmit this SKB on */
731	queue_index = skb_get_queue_mapping(skb);
732	queue = &np->queues[queue_index];
733
734	/* If skb->len is too big for wire format, drop skb and alert
735	* user about misconfiguration.
736	*/
737	if (unlikely(skb->len > XEN_NETIF_MAX_TX_SIZE)) {
738	net_alert_ratelimited(
739	"xennet: skb->len = %u, too big for wire format\n",
740	skb->len);
741	goto drop;
742	}
743
744	slots = xennet_count_skb_slots(skb);
745	if (unlikely(slots > MAX_XEN_SKB_FRAGS + 1)) {
746	net_dbg_ratelimited("xennet: skb rides the rocket: %d slots, %d bytes\n",
747	slots, skb->len);
748	if (skb_linearize(skb))
749	goto drop;
750	}
751
752	page = virt_to_page(skb->data);
753	offset = offset_in_page(skb->data);
754
755	/* The first req should be at least ETH_HLEN size or the packet will be
756	* dropped by netback.
757	*
758	* If the backend is not trusted bounce all data to zeroed pages to
759	* avoid exposing contiguous data on the granted page not belonging to
760	* the skb.
761	*/
762	if (np->bounce || unlikely(PAGE_SIZE - offset < ETH_HLEN)) {
763	nskb = bounce_skb(skb);
764	if (!nskb)
765	goto drop;
766	dev_consume_skb_any(skb);
767	skb = nskb;
768	page = virt_to_page(skb->data);
769	offset = offset_in_page(skb->data);
770	}
771
772	len = skb_headlen(skb);
773
774	spin_lock_irqsave(&queue->tx_lock, flags);
775
776	if (unlikely(!netif_carrier_ok(dev) ||
777	(slots > 1 && !xennet_can_sg(dev)) ||
778	netif_needs_gso(skb, netif_skb_features(skb)))) {
779	spin_unlock_irqrestore(lock: &queue->tx_lock, flags);
780	goto drop;
781	}
782
783	/* First request for the linear area. */
784	info.queue = queue;
785	info.skb = skb;
786	info.page = page;
787	first_tx = xennet_make_first_txreq(info: &info, offset, len);
788	offset += info.tx_local.size;
789	if (offset == PAGE_SIZE) {
790	page++;
791	offset = 0;
792	}
793	len -= info.tx_local.size;
794
795	if (skb->ip_summed == CHECKSUM_PARTIAL)
796	/* local packet? */
797	first_tx->flags |= XEN_NETTXF_csum_blank |
798	XEN_NETTXF_data_validated;
799	else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
800	/* remote but checksummed. */
801	first_tx->flags |= XEN_NETTXF_data_validated;
802
803	/* Optional extra info after the first request. */
804	if (skb_shinfo(skb)->gso_size) {
805	struct xen_netif_extra_info *gso;
806
807	gso = (struct xen_netif_extra_info *)
808	RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
809
810	first_tx->flags |= XEN_NETTXF_extra_info;
811
812	gso->u.gso.size = skb_shinfo(skb)->gso_size;
813	gso->u.gso.type = (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) ?
814	XEN_NETIF_GSO_TYPE_TCPV6 :
815	XEN_NETIF_GSO_TYPE_TCPV4;
816	gso->u.gso.pad = 0;
817	gso->u.gso.features = 0;
818
819	gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
820	gso->flags = 0;
821	}
822
823	/* Requests for the rest of the linear area. */
824	xennet_make_txreqs(info: &info, page, offset, len);
825
826	/* Requests for all the frags. */
827	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
828	skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
829	xennet_make_txreqs(info: &info, page: skb_frag_page(frag),
830	offset: skb_frag_off(frag),
831	len: skb_frag_size(frag));
832	}
833
834	/* First request has the packet length. */
835	first_tx->size = skb->len;
836
837	/* timestamp packet in software */
838	skb_tx_timestamp(skb);
839
840	xennet_mark_tx_pending(queue);
841
842	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
843	if (notify)
844	notify_remote_via_irq(irq: queue->tx_irq);
845
846	u64_stats_update_begin(syncp: &tx_stats->syncp);
847	tx_stats->bytes += skb->len;
848	tx_stats->packets++;
849	u64_stats_update_end(syncp: &tx_stats->syncp);
850
851	/* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
852	xennet_tx_buf_gc(queue);
853
854	if (!netfront_tx_slot_available(queue))
855	netif_tx_stop_queue(dev_queue: netdev_get_tx_queue(dev, index: queue->id));
856
857	spin_unlock_irqrestore(lock: &queue->tx_lock, flags);
858
859	return NETDEV_TX_OK;
860
861	drop:
862	dev->stats.tx_dropped++;
863	dev_kfree_skb_any(skb);
864	return NETDEV_TX_OK;
865	}
866
867	static int xennet_close(struct net_device *dev)
868	{
869	struct netfront_info *np = netdev_priv(dev);
870	unsigned int num_queues = dev->real_num_tx_queues;
871	unsigned int i;
872	struct netfront_queue *queue;
873	netif_tx_stop_all_queues(dev: np->netdev);
874	for (i = 0; i < num_queues; ++i) {
875	queue = &np->queues[i];
876	napi_disable(n: &queue->napi);
877	}
878	return 0;
879	}
880
881	static void xennet_destroy_queues(struct netfront_info *info)
882	{
883	unsigned int i;
884
885	for (i = 0; i < info->netdev->real_num_tx_queues; i++) {
886	struct netfront_queue *queue = &info->queues[i];
887
888	if (netif_running(dev: info->netdev))
889	napi_disable(n: &queue->napi);
890	netif_napi_del(napi: &queue->napi);
891	}
892
893	kfree(objp: info->queues);
894	info->queues = NULL;
895	}
896
897	static void xennet_uninit(struct net_device *dev)
898	{
899	struct netfront_info *np = netdev_priv(dev);
900	xennet_destroy_queues(info: np);
901	}
902
903	static void xennet_set_rx_rsp_cons(struct netfront_queue *queue, RING_IDX val)
904	{
905	unsigned long flags;
906
907	spin_lock_irqsave(&queue->rx_cons_lock, flags);
908	queue->rx.rsp_cons = val;
909	queue->rx_rsp_unconsumed = XEN_RING_NR_UNCONSUMED_RESPONSES(&queue->rx);
910	spin_unlock_irqrestore(lock: &queue->rx_cons_lock, flags);
911	}
912
913	static void xennet_move_rx_slot(struct netfront_queue *queue, struct sk_buff *skb,
914	grant_ref_t ref)
915	{
916	int new = xennet_rxidx(idx: queue->rx.req_prod_pvt);
917
918	BUG_ON(queue->rx_skbs[new]);
919	queue->rx_skbs[new] = skb;
920	queue->grant_rx_ref[new] = ref;
921	RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->id = new;
922	RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->gref = ref;
923	queue->rx.req_prod_pvt++;
924	}
925
926	static int xennet_get_extras(struct netfront_queue *queue,
927	struct xen_netif_extra_info *extras,
928	RING_IDX rp)
929
930	{
931	struct xen_netif_extra_info extra;
932	struct device *dev = &queue->info->netdev->dev;
933	RING_IDX cons = queue->rx.rsp_cons;
934	int err = 0;
935
936	do {
937	struct sk_buff *skb;
938	grant_ref_t ref;
939
940	if (unlikely(cons + 1 == rp)) {
941	if (net_ratelimit())
942	dev_warn(dev, "Missing extra info\n");
943	err = -EBADR;
944	break;
945	}
946
947	RING_COPY_RESPONSE(&queue->rx, ++cons, &extra);
948
949	if (unlikely(!extra.type ||
950	extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
951	if (net_ratelimit())
952	dev_warn(dev, "Invalid extra type: %d\n",
953	extra.type);
954	err = -EINVAL;
955	} else {
956	extras[extra.type - 1] = extra;
957	}
958
959	skb = xennet_get_rx_skb(queue, ri: cons);
960	ref = xennet_get_rx_ref(queue, ri: cons);
961	xennet_move_rx_slot(queue, skb, ref);
962	} while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
963
964	xennet_set_rx_rsp_cons(queue, val: cons);
965	return err;
966	}
967
968	static u32 xennet_run_xdp(struct netfront_queue *queue, struct page *pdata,
969	struct xen_netif_rx_response *rx, struct bpf_prog *prog,
970	struct xdp_buff *xdp, bool *need_xdp_flush)
971	{
972	struct xdp_frame *xdpf;
973	u32 len = rx->status;
974	u32 act;
975	int err;
976
977	xdp_init_buff(xdp, XEN_PAGE_SIZE - XDP_PACKET_HEADROOM,
978	rxq: &queue->xdp_rxq);
979	xdp_prepare_buff(xdp, page_address(pdata), XDP_PACKET_HEADROOM,
980	data_len: len, meta_valid: false);
981
982	act = bpf_prog_run_xdp(prog, xdp);
983	switch (act) {
984	case XDP_TX:
985	get_page(page: pdata);
986	xdpf = xdp_convert_buff_to_frame(xdp);
987	err = xennet_xdp_xmit(dev: queue->info->netdev, n: 1, frames: &xdpf, flags: 0);
988	if (unlikely(!err))
989	xdp_return_frame_rx_napi(xdpf);
990	else if (unlikely(err < 0))
991	trace_xdp_exception(dev: queue->info->netdev, xdp: prog, act);
992	break;
993	case XDP_REDIRECT:
994	get_page(page: pdata);
995	err = xdp_do_redirect(dev: queue->info->netdev, xdp, prog);
996	*need_xdp_flush = true;
997	if (unlikely(err))
998	trace_xdp_exception(dev: queue->info->netdev, xdp: prog, act);
999	break;
1000	case XDP_PASS:
1001	case XDP_DROP:
1002	break;
1003
1004	case XDP_ABORTED:
1005	trace_xdp_exception(dev: queue->info->netdev, xdp: prog, act);
1006	break;
1007
1008	default:
1009	bpf_warn_invalid_xdp_action(dev: queue->info->netdev, prog, act);
1010	}
1011
1012	return act;
1013	}
1014
1015	static int xennet_get_responses(struct netfront_queue *queue,
1016	struct netfront_rx_info *rinfo, RING_IDX rp,
1017	struct sk_buff_head *list,
1018	bool *need_xdp_flush)
1019	{
1020	struct xen_netif_rx_response *rx = &rinfo->rx, rx_local;
1021	int max = XEN_NETIF_NR_SLOTS_MIN + (rx->status <= RX_COPY_THRESHOLD);
1022	RING_IDX cons = queue->rx.rsp_cons;
1023	struct sk_buff *skb = xennet_get_rx_skb(queue, ri: cons);
1024	struct xen_netif_extra_info *extras = rinfo->extras;
1025	grant_ref_t ref = xennet_get_rx_ref(queue, ri: cons);
1026	struct device *dev = &queue->info->netdev->dev;
1027	struct bpf_prog *xdp_prog;
1028	struct xdp_buff xdp;
1029	int slots = 1;
1030	int err = 0;
1031	u32 verdict;
1032
1033	if (rx->flags & XEN_NETRXF_extra_info) {
1034	err = xennet_get_extras(queue, extras, rp);
1035	if (!err) {
1036	if (extras[XEN_NETIF_EXTRA_TYPE_XDP - 1].type) {
1037	struct xen_netif_extra_info *xdp;
1038
1039	xdp = &extras[XEN_NETIF_EXTRA_TYPE_XDP - 1];
1040	rx->offset = xdp->u.xdp.headroom;
1041	}
1042	}
1043	cons = queue->rx.rsp_cons;
1044	}
1045
1046	for (;;) {
1047	/*
1048	* This definitely indicates a bug, either in this driver or in
1049	* the backend driver. In future this should flag the bad
1050	* situation to the system controller to reboot the backend.
1051	*/
1052	if (ref == INVALID_GRANT_REF) {
1053	if (net_ratelimit())
1054	dev_warn(dev, "Bad rx response id %d.\n",
1055	rx->id);
1056	err = -EINVAL;
1057	goto next;
1058	}
1059
1060	if (unlikely(rx->status < 0 ||
1061	rx->offset + rx->status > XEN_PAGE_SIZE)) {
1062	if (net_ratelimit())
1063	dev_warn(dev, "rx->offset: %u, size: %d\n",
1064	rx->offset, rx->status);
1065	xennet_move_rx_slot(queue, skb, ref);
1066	err = -EINVAL;
1067	goto next;
1068	}
1069
1070	if (!gnttab_end_foreign_access_ref(ref)) {
1071	dev_alert(dev,
1072	"Grant still in use by backend domain\n");
1073	queue->info->broken = true;
1074	dev_alert(dev, "Disabled for further use\n");
1075	return -EINVAL;
1076	}
1077
1078	gnttab_release_grant_reference(private_head: &queue->gref_rx_head, release: ref);
1079
1080	rcu_read_lock();
1081	xdp_prog = rcu_dereference(queue->xdp_prog);
1082	if (xdp_prog) {
1083	if (!(rx->flags & XEN_NETRXF_more_data)) {
1084	/* currently only a single page contains data */
1085	verdict = xennet_run_xdp(queue,
1086	pdata: skb_frag_page(frag: &skb_shinfo(skb)->frags[0]),
1087	rx, prog: xdp_prog, xdp: &xdp, need_xdp_flush);
1088	if (verdict != XDP_PASS)
1089	err = -EINVAL;
1090	} else {
1091	/* drop the frame */
1092	err = -EINVAL;
1093	}
1094	}
1095	rcu_read_unlock();
1096
1097	__skb_queue_tail(list, newsk: skb);
1098
1099	next:
1100	if (!(rx->flags & XEN_NETRXF_more_data))
1101	break;
1102
1103	if (cons + slots == rp) {
1104	if (net_ratelimit())
1105	dev_warn(dev, "Need more slots\n");
1106	err = -ENOENT;
1107	break;
1108	}
1109
1110	RING_COPY_RESPONSE(&queue->rx, cons + slots, &rx_local);
1111	rx = &rx_local;
1112	skb = xennet_get_rx_skb(queue, ri: cons + slots);
1113	ref = xennet_get_rx_ref(queue, ri: cons + slots);
1114	slots++;
1115	}
1116
1117	if (unlikely(slots > max)) {
1118	if (net_ratelimit())
1119	dev_warn(dev, "Too many slots\n");
1120	err = -E2BIG;
1121	}
1122
1123	if (unlikely(err))
1124	xennet_set_rx_rsp_cons(queue, val: cons + slots);
1125
1126	return err;
1127	}
1128
1129	static int xennet_set_skb_gso(struct sk_buff *skb,
1130	struct xen_netif_extra_info *gso)
1131	{
1132	if (!gso->u.gso.size) {
1133	if (net_ratelimit())
1134	pr_warn("GSO size must not be zero\n");
1135	return -EINVAL;
1136	}
1137
1138	if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4 &&
1139	gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV6) {
1140	if (net_ratelimit())
1141	pr_warn("Bad GSO type %d\n", gso->u.gso.type);
1142	return -EINVAL;
1143	}
1144
1145	skb_shinfo(skb)->gso_size = gso->u.gso.size;
1146	skb_shinfo(skb)->gso_type =
1147	(gso->u.gso.type == XEN_NETIF_GSO_TYPE_TCPV4) ?
1148	SKB_GSO_TCPV4 :
1149	SKB_GSO_TCPV6;
1150
1151	/* Header must be checked, and gso_segs computed. */
1152	skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1153	skb_shinfo(skb)->gso_segs = 0;
1154
1155	return 0;
1156	}
1157
1158	static int xennet_fill_frags(struct netfront_queue *queue,
1159	struct sk_buff *skb,
1160	struct sk_buff_head *list)
1161	{
1162	RING_IDX cons = queue->rx.rsp_cons;
1163	struct sk_buff *nskb;
1164
1165	while ((nskb = __skb_dequeue(list))) {
1166	struct xen_netif_rx_response rx;
1167	skb_frag_t *nfrag = &skb_shinfo(nskb)->frags[0];
1168
1169	RING_COPY_RESPONSE(&queue->rx, ++cons, &rx);
1170
1171	if (skb_shinfo(skb)->nr_frags == MAX_SKB_FRAGS) {
1172	unsigned int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
1173
1174	BUG_ON(pull_to < skb_headlen(skb));
1175	__pskb_pull_tail(skb, delta: pull_to - skb_headlen(skb));
1176	}
1177	if (unlikely(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS)) {
1178	xennet_set_rx_rsp_cons(queue,
1179	val: ++cons + skb_queue_len(list_: list));
1180	kfree_skb(skb: nskb);
1181	return -ENOENT;
1182	}
1183
1184	skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
1185	page: skb_frag_page(frag: nfrag),
1186	off: rx.offset, size: rx.status, PAGE_SIZE);
1187
1188	skb_shinfo(nskb)->nr_frags = 0;
1189	kfree_skb(skb: nskb);
1190	}
1191
1192	xennet_set_rx_rsp_cons(queue, val: cons);
1193
1194	return 0;
1195	}
1196
1197	static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
1198	{
1199	bool recalculate_partial_csum = false;
1200
1201	/*
1202	* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1203	* peers can fail to set NETRXF_csum_blank when sending a GSO
1204	* frame. In this case force the SKB to CHECKSUM_PARTIAL and
1205	* recalculate the partial checksum.
1206	*/
1207	if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1208	struct netfront_info *np = netdev_priv(dev);
1209	atomic_inc(v: &np->rx_gso_checksum_fixup);
1210	skb->ip_summed = CHECKSUM_PARTIAL;
1211	recalculate_partial_csum = true;
1212	}
1213
1214	/* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1215	if (skb->ip_summed != CHECKSUM_PARTIAL)
1216	return 0;
1217
1218	return skb_checksum_setup(skb, recalculate: recalculate_partial_csum);
1219	}
1220
1221	static int handle_incoming_queue(struct netfront_queue *queue,
1222	struct sk_buff_head *rxq)
1223	{
1224	struct netfront_stats *rx_stats = this_cpu_ptr(queue->info->rx_stats);
1225	int packets_dropped = 0;
1226	struct sk_buff *skb;
1227
1228	while ((skb = __skb_dequeue(list: rxq)) != NULL) {
1229	int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
1230
1231	if (pull_to > skb_headlen(skb))
1232	__pskb_pull_tail(skb, delta: pull_to - skb_headlen(skb));
1233
1234	/* Ethernet work: Delayed to here as it peeks the header. */
1235	skb->protocol = eth_type_trans(skb, dev: queue->info->netdev);
1236	skb_reset_network_header(skb);
1237
1238	if (checksum_setup(dev: queue->info->netdev, skb)) {
1239	kfree_skb(skb);
1240	packets_dropped++;
1241	queue->info->netdev->stats.rx_errors++;
1242	continue;
1243	}
1244
1245	u64_stats_update_begin(syncp: &rx_stats->syncp);
1246	rx_stats->packets++;
1247	rx_stats->bytes += skb->len;
1248	u64_stats_update_end(syncp: &rx_stats->syncp);
1249
1250	/* Pass it up. */
1251	napi_gro_receive(napi: &queue->napi, skb);
1252	}
1253
1254	return packets_dropped;
1255	}
1256
1257	static int xennet_poll(struct napi_struct *napi, int budget)
1258	{
1259	struct netfront_queue *queue = container_of(napi, struct netfront_queue, napi);
1260	struct net_device *dev = queue->info->netdev;
1261	struct sk_buff *skb;
1262	struct netfront_rx_info rinfo;
1263	struct xen_netif_rx_response *rx = &rinfo.rx;
1264	struct xen_netif_extra_info *extras = rinfo.extras;
1265	RING_IDX i, rp;
1266	int work_done;
1267	struct sk_buff_head rxq;
1268	struct sk_buff_head errq;
1269	struct sk_buff_head tmpq;
1270	int err;
1271	bool need_xdp_flush = false;
1272
1273	spin_lock(lock: &queue->rx_lock);
1274
1275	skb_queue_head_init(list: &rxq);
1276	skb_queue_head_init(list: &errq);
1277	skb_queue_head_init(list: &tmpq);
1278
1279	rp = queue->rx.sring->rsp_prod;
1280	if (RING_RESPONSE_PROD_OVERFLOW(&queue->rx, rp)) {
1281	dev_alert(&dev->dev, "Illegal number of responses %u\n",
1282	rp - queue->rx.rsp_cons);
1283	queue->info->broken = true;
1284	spin_unlock(lock: &queue->rx_lock);
1285	return 0;
1286	}
1287	rmb(); /* Ensure we see queued responses up to 'rp'. */
1288
1289	i = queue->rx.rsp_cons;
1290	work_done = 0;
1291	while ((i != rp) && (work_done < budget)) {
1292	RING_COPY_RESPONSE(&queue->rx, i, rx);
1293	memset(extras, 0, sizeof(rinfo.extras));
1294
1295	err = xennet_get_responses(queue, rinfo: &rinfo, rp, list: &tmpq,
1296	need_xdp_flush: &need_xdp_flush);
1297
1298	if (unlikely(err)) {
1299	if (queue->info->broken) {
1300	spin_unlock(lock: &queue->rx_lock);
1301	return 0;
1302	}
1303	err:
1304	while ((skb = __skb_dequeue(list: &tmpq)))
1305	__skb_queue_tail(list: &errq, newsk: skb);
1306	dev->stats.rx_errors++;
1307	i = queue->rx.rsp_cons;
1308	continue;
1309	}
1310
1311	skb = __skb_dequeue(list: &tmpq);
1312
1313	if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1314	struct xen_netif_extra_info *gso;
1315	gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1316
1317	if (unlikely(xennet_set_skb_gso(skb, gso))) {
1318	__skb_queue_head(list: &tmpq, newsk: skb);
1319	xennet_set_rx_rsp_cons(queue,
1320	val: queue->rx.rsp_cons +
1321	skb_queue_len(list_: &tmpq));
1322	goto err;
1323	}
1324	}
1325
1326	NETFRONT_SKB_CB(skb)->pull_to = rx->status;
1327	if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD)
1328	NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD;
1329
1330	skb_frag_off_set(frag: &skb_shinfo(skb)->frags[0], offset: rx->offset);
1331	skb_frag_size_set(frag: &skb_shinfo(skb)->frags[0], size: rx->status);
1332	skb->data_len = rx->status;
1333	skb->len += rx->status;
1334
1335	if (unlikely(xennet_fill_frags(queue, skb, &tmpq)))
1336	goto err;
1337
1338	if (rx->flags & XEN_NETRXF_csum_blank)
1339	skb->ip_summed = CHECKSUM_PARTIAL;
1340	else if (rx->flags & XEN_NETRXF_data_validated)
1341	skb->ip_summed = CHECKSUM_UNNECESSARY;
1342
1343	__skb_queue_tail(list: &rxq, newsk: skb);
1344
1345	i = queue->rx.rsp_cons + 1;
1346	xennet_set_rx_rsp_cons(queue, val: i);
1347	work_done++;
1348	}
1349	if (need_xdp_flush)
1350	xdp_do_flush();
1351
1352	__skb_queue_purge(list: &errq);
1353
1354	work_done -= handle_incoming_queue(queue, rxq: &rxq);
1355
1356	xennet_alloc_rx_buffers(queue);
1357
1358	if (work_done < budget) {
1359	int more_to_do = 0;
1360
1361	napi_complete_done(n: napi, work_done);
1362
1363	RING_FINAL_CHECK_FOR_RESPONSES(&queue->rx, more_to_do);
1364	if (more_to_do)
1365	napi_schedule(n: napi);
1366	}
1367
1368	spin_unlock(lock: &queue->rx_lock);
1369
1370	return work_done;
1371	}
1372
1373	static int xennet_change_mtu(struct net_device *dev, int mtu)
1374	{
1375	int max = xennet_can_sg(dev) ? XEN_NETIF_MAX_TX_SIZE : ETH_DATA_LEN;
1376
1377	if (mtu > max)
1378	return -EINVAL;
1379	dev->mtu = mtu;
1380	return 0;
1381	}
1382
1383	static void xennet_get_stats64(struct net_device *dev,
1384	struct rtnl_link_stats64 *tot)
1385	{
1386	struct netfront_info *np = netdev_priv(dev);
1387	int cpu;
1388
1389	for_each_possible_cpu(cpu) {
1390	struct netfront_stats *rx_stats = per_cpu_ptr(np->rx_stats, cpu);
1391	struct netfront_stats *tx_stats = per_cpu_ptr(np->tx_stats, cpu);
1392	u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
1393	unsigned int start;
1394
1395	do {
1396	start = u64_stats_fetch_begin(syncp: &tx_stats->syncp);
1397	tx_packets = tx_stats->packets;
1398	tx_bytes = tx_stats->bytes;
1399	} while (u64_stats_fetch_retry(syncp: &tx_stats->syncp, start));
1400
1401	do {
1402	start = u64_stats_fetch_begin(syncp: &rx_stats->syncp);
1403	rx_packets = rx_stats->packets;
1404	rx_bytes = rx_stats->bytes;
1405	} while (u64_stats_fetch_retry(syncp: &rx_stats->syncp, start));
1406
1407	tot->rx_packets += rx_packets;
1408	tot->tx_packets += tx_packets;
1409	tot->rx_bytes += rx_bytes;
1410	tot->tx_bytes += tx_bytes;
1411	}
1412
1413	tot->rx_errors = dev->stats.rx_errors;
1414	tot->tx_dropped = dev->stats.tx_dropped;
1415	}
1416
1417	static void xennet_release_tx_bufs(struct netfront_queue *queue)
1418	{
1419	struct sk_buff *skb;
1420	int i;
1421
1422	for (i = 0; i < NET_TX_RING_SIZE; i++) {
1423	/* Skip over entries which are actually freelist references */
1424	if (!queue->tx_skbs[i])
1425	continue;
1426
1427	skb = queue->tx_skbs[i];
1428	queue->tx_skbs[i] = NULL;
1429	get_page(page: queue->grant_tx_page[i]);
1430	gnttab_end_foreign_access(ref: queue->grant_tx_ref[i],
1431	page: queue->grant_tx_page[i]);
1432	queue->grant_tx_page[i] = NULL;
1433	queue->grant_tx_ref[i] = INVALID_GRANT_REF;
1434	add_id_to_list(head: &queue->tx_skb_freelist, list: queue->tx_link, id: i);
1435	dev_kfree_skb_irq(skb);
1436	}
1437	}
1438
1439	static void xennet_release_rx_bufs(struct netfront_queue *queue)
1440	{
1441	int id, ref;
1442
1443	spin_lock_bh(lock: &queue->rx_lock);
1444
1445	for (id = 0; id < NET_RX_RING_SIZE; id++) {
1446	struct sk_buff *skb;
1447	struct page *page;
1448
1449	skb = queue->rx_skbs[id];
1450	if (!skb)
1451	continue;
1452
1453	ref = queue->grant_rx_ref[id];
1454	if (ref == INVALID_GRANT_REF)
1455	continue;
1456
1457	page = skb_frag_page(frag: &skb_shinfo(skb)->frags[0]);
1458
1459	/* gnttab_end_foreign_access() needs a page ref until
1460	* foreign access is ended (which may be deferred).
1461	*/
1462	get_page(page);
1463	gnttab_end_foreign_access(ref, page);
1464	queue->grant_rx_ref[id] = INVALID_GRANT_REF;
1465
1466	kfree_skb(skb);
1467	}
1468
1469	spin_unlock_bh(lock: &queue->rx_lock);
1470	}
1471
1472	static netdev_features_t xennet_fix_features(struct net_device *dev,
1473	netdev_features_t features)
1474	{
1475	struct netfront_info *np = netdev_priv(dev);
1476
1477	if (features & NETIF_F_SG &&
1478	!xenbus_read_unsigned(dir: np->xbdev->otherend, node: "feature-sg", default_val: 0))
1479	features &= ~NETIF_F_SG;
1480
1481	if (features & NETIF_F_IPV6_CSUM &&
1482	!xenbus_read_unsigned(dir: np->xbdev->otherend,
1483	node: "feature-ipv6-csum-offload", default_val: 0))
1484	features &= ~NETIF_F_IPV6_CSUM;
1485
1486	if (features & NETIF_F_TSO &&
1487	!xenbus_read_unsigned(dir: np->xbdev->otherend, node: "feature-gso-tcpv4", default_val: 0))
1488	features &= ~NETIF_F_TSO;
1489
1490	if (features & NETIF_F_TSO6 &&
1491	!xenbus_read_unsigned(dir: np->xbdev->otherend, node: "feature-gso-tcpv6", default_val: 0))
1492	features &= ~NETIF_F_TSO6;
1493
1494	return features;
1495	}
1496
1497	static int xennet_set_features(struct net_device *dev,
1498	netdev_features_t features)
1499	{
1500	if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN) {
1501	netdev_info(dev, format: "Reducing MTU because no SG offload");
1502	dev->mtu = ETH_DATA_LEN;
1503	}
1504
1505	return 0;
1506	}
1507
1508	static bool xennet_handle_tx(struct netfront_queue *queue, unsigned int *eoi)
1509	{
1510	unsigned long flags;
1511
1512	if (unlikely(queue->info->broken))
1513	return false;
1514
1515	spin_lock_irqsave(&queue->tx_lock, flags);
1516	if (xennet_tx_buf_gc(queue))
1517	*eoi = 0;
1518	spin_unlock_irqrestore(lock: &queue->tx_lock, flags);
1519
1520	return true;
1521	}
1522
1523	static irqreturn_t xennet_tx_interrupt(int irq, void *dev_id)
1524	{
1525	unsigned int eoiflag = XEN_EOI_FLAG_SPURIOUS;
1526
1527	if (likely(xennet_handle_tx(dev_id, &eoiflag)))
1528	xen_irq_lateeoi(irq, eoi_flags: eoiflag);
1529
1530	return IRQ_HANDLED;
1531	}
1532
1533	static bool xennet_handle_rx(struct netfront_queue *queue, unsigned int *eoi)
1534	{
1535	unsigned int work_queued;
1536	unsigned long flags;
1537
1538	if (unlikely(queue->info->broken))
1539	return false;
1540
1541	spin_lock_irqsave(&queue->rx_cons_lock, flags);
1542	work_queued = XEN_RING_NR_UNCONSUMED_RESPONSES(&queue->rx);
1543	if (work_queued > queue->rx_rsp_unconsumed) {
1544	queue->rx_rsp_unconsumed = work_queued;
1545	*eoi = 0;
1546	} else if (unlikely(work_queued < queue->rx_rsp_unconsumed)) {
1547	const struct device *dev = &queue->info->netdev->dev;
1548
1549	spin_unlock_irqrestore(lock: &queue->rx_cons_lock, flags);
1550	dev_alert(dev, "RX producer index going backwards\n");
1551	dev_alert(dev, "Disabled for further use\n");
1552	queue->info->broken = true;
1553	return false;
1554	}
1555	spin_unlock_irqrestore(lock: &queue->rx_cons_lock, flags);
1556
1557	if (likely(netif_carrier_ok(queue->info->netdev) && work_queued))
1558	napi_schedule(n: &queue->napi);
1559
1560	return true;
1561	}
1562
1563	static irqreturn_t xennet_rx_interrupt(int irq, void *dev_id)
1564	{
1565	unsigned int eoiflag = XEN_EOI_FLAG_SPURIOUS;
1566
1567	if (likely(xennet_handle_rx(dev_id, &eoiflag)))
1568	xen_irq_lateeoi(irq, eoi_flags: eoiflag);
1569
1570	return IRQ_HANDLED;
1571	}
1572
1573	static irqreturn_t xennet_interrupt(int irq, void *dev_id)
1574	{
1575	unsigned int eoiflag = XEN_EOI_FLAG_SPURIOUS;
1576
1577	if (xennet_handle_tx(queue: dev_id, eoi: &eoiflag) &&
1578	xennet_handle_rx(queue: dev_id, eoi: &eoiflag))
1579	xen_irq_lateeoi(irq, eoi_flags: eoiflag);
1580
1581	return IRQ_HANDLED;
1582	}
1583
1584	#ifdef CONFIG_NET_POLL_CONTROLLER
1585	static void xennet_poll_controller(struct net_device *dev)
1586	{
1587	/* Poll each queue */
1588	struct netfront_info *info = netdev_priv(dev);
1589	unsigned int num_queues = dev->real_num_tx_queues;
1590	unsigned int i;
1591
1592	if (info->broken)
1593	return;
1594
1595	for (i = 0; i < num_queues; ++i)
1596	xennet_interrupt(irq: 0, dev_id: &info->queues[i]);
1597	}
1598	#endif
1599
1600	#define NETBACK_XDP_HEADROOM_DISABLE 0
1601	#define NETBACK_XDP_HEADROOM_ENABLE 1
1602
1603	static int talk_to_netback_xdp(struct netfront_info *np, int xdp)
1604	{
1605	int err;
1606	unsigned short headroom;
1607
1608	headroom = xdp ? XDP_PACKET_HEADROOM : 0;
1609	err = xenbus_printf(XBT_NIL, dir: np->xbdev->nodename,
1610	node: "xdp-headroom", fmt: "%hu",
1611	headroom);
1612	if (err)
1613	pr_warn("Error writing xdp-headroom\n");
1614
1615	return err;
1616	}
1617
1618	static int xennet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1619	struct netlink_ext_ack *extack)
1620	{
1621	unsigned long max_mtu = XEN_PAGE_SIZE - XDP_PACKET_HEADROOM;
1622	struct netfront_info *np = netdev_priv(dev);
1623	struct bpf_prog *old_prog;
1624	unsigned int i, err;
1625
1626	if (dev->mtu > max_mtu) {
1627	netdev_warn(dev, format: "XDP requires MTU less than %lu\n", max_mtu);
1628	return -EINVAL;
1629	}
1630
1631	if (!np->netback_has_xdp_headroom)
1632	return 0;
1633
1634	xenbus_switch_state(dev: np->xbdev, new_state: XenbusStateReconfiguring);
1635
1636	err = talk_to_netback_xdp(np, xdp: prog ? NETBACK_XDP_HEADROOM_ENABLE :
1637	NETBACK_XDP_HEADROOM_DISABLE);
1638	if (err)
1639	return err;
1640
1641	/* avoid the race with XDP headroom adjustment */
1642	wait_event(module_wq,
1643	xenbus_read_driver_state(np->xbdev->otherend) ==
1644	XenbusStateReconfigured);
1645	np->netfront_xdp_enabled = true;
1646
1647	old_prog = rtnl_dereference(np->queues[0].xdp_prog);
1648
1649	if (prog)
1650	bpf_prog_add(prog, i: dev->real_num_tx_queues);
1651
1652	for (i = 0; i < dev->real_num_tx_queues; ++i)
1653	rcu_assign_pointer(np->queues[i].xdp_prog, prog);
1654
1655	if (old_prog)
1656	for (i = 0; i < dev->real_num_tx_queues; ++i)
1657	bpf_prog_put(prog: old_prog);
1658
1659	xenbus_switch_state(dev: np->xbdev, new_state: XenbusStateConnected);
1660
1661	return 0;
1662	}
1663
1664	static int xennet_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1665	{
1666	struct netfront_info *np = netdev_priv(dev);
1667
1668	if (np->broken)
1669	return -ENODEV;
1670
1671	switch (xdp->command) {
1672	case XDP_SETUP_PROG:
1673	return xennet_xdp_set(dev, prog: xdp->prog, extack: xdp->extack);
1674	default:
1675	return -EINVAL;
1676	}
1677	}
1678
1679	static const struct net_device_ops xennet_netdev_ops = {
1680	.ndo_uninit = xennet_uninit,
1681	.ndo_open = xennet_open,
1682	.ndo_stop = xennet_close,
1683	.ndo_start_xmit = xennet_start_xmit,
1684	.ndo_change_mtu = xennet_change_mtu,
1685	.ndo_get_stats64 = xennet_get_stats64,
1686	.ndo_set_mac_address = eth_mac_addr,
1687	.ndo_validate_addr = eth_validate_addr,
1688	.ndo_fix_features = xennet_fix_features,
1689	.ndo_set_features = xennet_set_features,
1690	.ndo_select_queue = xennet_select_queue,
1691	.ndo_bpf = xennet_xdp,
1692	.ndo_xdp_xmit = xennet_xdp_xmit,
1693	#ifdef CONFIG_NET_POLL_CONTROLLER
1694	.ndo_poll_controller = xennet_poll_controller,
1695	#endif
1696	};
1697
1698	static void xennet_free_netdev(struct net_device *netdev)
1699	{
1700	struct netfront_info *np = netdev_priv(dev: netdev);
1701
1702	free_percpu(pdata: np->rx_stats);
1703	free_percpu(pdata: np->tx_stats);
1704	free_netdev(dev: netdev);
1705	}
1706
1707	static struct net_device *xennet_create_dev(struct xenbus_device *dev)
1708	{
1709	int err;
1710	struct net_device *netdev;
1711	struct netfront_info *np;
1712
1713	netdev = alloc_etherdev_mq(sizeof(struct netfront_info), xennet_max_queues);
1714	if (!netdev)
1715	return ERR_PTR(error: -ENOMEM);
1716
1717	np = netdev_priv(dev: netdev);
1718	np->xbdev = dev;
1719
1720	np->queues = NULL;
1721
1722	err = -ENOMEM;
1723	np->rx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1724	if (np->rx_stats == NULL)
1725	goto exit;
1726	np->tx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1727	if (np->tx_stats == NULL)
1728	goto exit;
1729
1730	netdev->netdev_ops = &xennet_netdev_ops;
1731
1732	netdev->features = NETIF_F_IP_CSUM | NETIF_F_RXCSUM |
1733	NETIF_F_GSO_ROBUST;
1734	netdev->hw_features = NETIF_F_SG |
1735	NETIF_F_IPV6_CSUM |
1736	NETIF_F_TSO | NETIF_F_TSO6;
1737
1738	/*
1739	* Assume that all hw features are available for now. This set
1740	* will be adjusted by the call to netdev_update_features() in
1741	* xennet_connect() which is the earliest point where we can
1742	* negotiate with the backend regarding supported features.
1743	*/
1744	netdev->features |= netdev->hw_features;
1745	netdev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
1746	NETDEV_XDP_ACT_NDO_XMIT;
1747
1748	netdev->ethtool_ops = &xennet_ethtool_ops;
1749	netdev->min_mtu = ETH_MIN_MTU;
1750	netdev->max_mtu = XEN_NETIF_MAX_TX_SIZE;
1751	SET_NETDEV_DEV(netdev, &dev->dev);
1752
1753	np->netdev = netdev;
1754	np->netfront_xdp_enabled = false;
1755
1756	netif_carrier_off(dev: netdev);
1757
1758	do {
1759	xenbus_switch_state(dev, new_state: XenbusStateInitialising);
1760	err = wait_event_timeout(module_wq,
1761	xenbus_read_driver_state(dev->otherend) !=
1762	XenbusStateClosed &&
1763	xenbus_read_driver_state(dev->otherend) !=
1764	XenbusStateUnknown, XENNET_TIMEOUT);
1765	} while (!err);
1766
1767	return netdev;
1768
1769	exit:
1770	xennet_free_netdev(netdev);
1771	return ERR_PTR(error: err);
1772	}
1773
1774	/*
1775	* Entry point to this code when a new device is created. Allocate the basic
1776	* structures and the ring buffers for communication with the backend, and
1777	* inform the backend of the appropriate details for those.
1778	*/
1779	static int netfront_probe(struct xenbus_device *dev,
1780	const struct xenbus_device_id *id)
1781	{
1782	int err;
1783	struct net_device *netdev;
1784	struct netfront_info *info;
1785
1786	netdev = xennet_create_dev(dev);
1787	if (IS_ERR(ptr: netdev)) {
1788	err = PTR_ERR(ptr: netdev);
1789	xenbus_dev_fatal(dev, err, fmt: "creating netdev");
1790	return err;
1791	}
1792
1793	info = netdev_priv(dev: netdev);
1794	dev_set_drvdata(dev: &dev->dev, data: info);
1795	#ifdef CONFIG_SYSFS
1796	info->netdev->sysfs_groups[0] = &xennet_dev_group;
1797	#endif
1798
1799	return 0;
1800	}
1801
1802	static void xennet_end_access(int ref, void *page)
1803	{
1804	/* This frees the page as a side-effect */
1805	if (ref != INVALID_GRANT_REF)
1806	gnttab_end_foreign_access(ref, virt_to_page(page));
1807	}
1808
1809	static void xennet_disconnect_backend(struct netfront_info *info)
1810	{
1811	unsigned int i = 0;
1812	unsigned int num_queues = info->netdev->real_num_tx_queues;
1813
1814	netif_carrier_off(dev: info->netdev);
1815
1816	for (i = 0; i < num_queues && info->queues; ++i) {
1817	struct netfront_queue *queue = &info->queues[i];
1818
1819	del_timer_sync(timer: &queue->rx_refill_timer);
1820
1821	if (queue->tx_irq && (queue->tx_irq == queue->rx_irq))
1822	unbind_from_irqhandler(irq: queue->tx_irq, dev_id: queue);
1823	if (queue->tx_irq && (queue->tx_irq != queue->rx_irq)) {
1824	unbind_from_irqhandler(irq: queue->tx_irq, dev_id: queue);
1825	unbind_from_irqhandler(irq: queue->rx_irq, dev_id: queue);
1826	}
1827	queue->tx_evtchn = queue->rx_evtchn = 0;
1828	queue->tx_irq = queue->rx_irq = 0;
1829
1830	if (netif_running(dev: info->netdev))
1831	napi_synchronize(n: &queue->napi);
1832
1833	xennet_release_tx_bufs(queue);
1834	xennet_release_rx_bufs(queue);
1835	gnttab_free_grant_references(head: queue->gref_tx_head);
1836	gnttab_free_grant_references(head: queue->gref_rx_head);
1837
1838	/* End access and free the pages */
1839	xennet_end_access(ref: queue->tx_ring_ref, page: queue->tx.sring);
1840	xennet_end_access(ref: queue->rx_ring_ref, page: queue->rx.sring);
1841
1842	queue->tx_ring_ref = INVALID_GRANT_REF;
1843	queue->rx_ring_ref = INVALID_GRANT_REF;
1844	queue->tx.sring = NULL;
1845	queue->rx.sring = NULL;
1846
1847	page_pool_destroy(pool: queue->page_pool);
1848	}
1849	}
1850
1851	/*
1852	* We are reconnecting to the backend, due to a suspend/resume, or a backend
1853	* driver restart. We tear down our netif structure and recreate it, but
1854	* leave the device-layer structures intact so that this is transparent to the
1855	* rest of the kernel.
1856	*/
1857	static int netfront_resume(struct xenbus_device *dev)
1858	{
1859	struct netfront_info *info = dev_get_drvdata(dev: &dev->dev);
1860
1861	dev_dbg(&dev->dev, "%s\n", dev->nodename);
1862
1863	netif_tx_lock_bh(dev: info->netdev);
1864	netif_device_detach(dev: info->netdev);
1865	netif_tx_unlock_bh(dev: info->netdev);
1866
1867	xennet_disconnect_backend(info);
1868
1869	rtnl_lock();
1870	if (info->queues)
1871	xennet_destroy_queues(info);
1872	rtnl_unlock();
1873
1874	return 0;
1875	}
1876
1877	static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
1878	{
1879	char *s, *e, *macstr;
1880	int i;
1881
1882	macstr = s = xenbus_read(XBT_NIL, dir: dev->nodename, node: "mac", NULL);
1883	if (IS_ERR(macstr))
1884	return PTR_ERR(macstr);
1885
1886	for (i = 0; i < ETH_ALEN; i++) {
1887	mac[i] = simple_strtoul(s, &e, 16);
1888	if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
1889	kfree(macstr);
1890	return -ENOENT;
1891	}
1892	s = e+1;
1893	}
1894
1895	kfree(macstr);
1896	return 0;
1897	}
1898
1899	static int setup_netfront_single(struct netfront_queue *queue)
1900	{
1901	int err;
1902
1903	err = xenbus_alloc_evtchn(dev: queue->info->xbdev, port: &queue->tx_evtchn);
1904	if (err < 0)
1905	goto fail;
1906
1907	err = bind_evtchn_to_irqhandler_lateeoi(evtchn: queue->tx_evtchn,
1908	handler: xennet_interrupt, irqflags: 0,
1909	devname: queue->info->netdev->name,
1910	dev_id: queue);
1911	if (err < 0)
1912	goto bind_fail;
1913	queue->rx_evtchn = queue->tx_evtchn;
1914	queue->rx_irq = queue->tx_irq = err;
1915
1916	return 0;
1917
1918	bind_fail:
1919	xenbus_free_evtchn(dev: queue->info->xbdev, port: queue->tx_evtchn);
1920	queue->tx_evtchn = 0;
1921	fail:
1922	return err;
1923	}
1924
1925	static int setup_netfront_split(struct netfront_queue *queue)
1926	{
1927	int err;
1928
1929	err = xenbus_alloc_evtchn(dev: queue->info->xbdev, port: &queue->tx_evtchn);
1930	if (err < 0)
1931	goto fail;
1932	err = xenbus_alloc_evtchn(dev: queue->info->xbdev, port: &queue->rx_evtchn);
1933	if (err < 0)
1934	goto alloc_rx_evtchn_fail;
1935
1936	snprintf(buf: queue->tx_irq_name, size: sizeof(queue->tx_irq_name),
1937	fmt: "%s-tx", queue->name);
1938	err = bind_evtchn_to_irqhandler_lateeoi(evtchn: queue->tx_evtchn,
1939	handler: xennet_tx_interrupt, irqflags: 0,
1940	devname: queue->tx_irq_name, dev_id: queue);
1941	if (err < 0)
1942	goto bind_tx_fail;
1943	queue->tx_irq = err;
1944
1945	snprintf(buf: queue->rx_irq_name, size: sizeof(queue->rx_irq_name),
1946	fmt: "%s-rx", queue->name);
1947	err = bind_evtchn_to_irqhandler_lateeoi(evtchn: queue->rx_evtchn,
1948	handler: xennet_rx_interrupt, irqflags: 0,
1949	devname: queue->rx_irq_name, dev_id: queue);
1950	if (err < 0)
1951	goto bind_rx_fail;
1952	queue->rx_irq = err;
1953
1954	return 0;
1955
1956	bind_rx_fail:
1957	unbind_from_irqhandler(irq: queue->tx_irq, dev_id: queue);
1958	queue->tx_irq = 0;
1959	bind_tx_fail:
1960	xenbus_free_evtchn(dev: queue->info->xbdev, port: queue->rx_evtchn);
1961	queue->rx_evtchn = 0;
1962	alloc_rx_evtchn_fail:
1963	xenbus_free_evtchn(dev: queue->info->xbdev, port: queue->tx_evtchn);
1964	queue->tx_evtchn = 0;
1965	fail:
1966	return err;
1967	}
1968
1969	static int setup_netfront(struct xenbus_device *dev,
1970	struct netfront_queue *queue, unsigned int feature_split_evtchn)
1971	{
1972	struct xen_netif_tx_sring *txs;
1973	struct xen_netif_rx_sring *rxs;
1974	int err;
1975
1976	queue->tx_ring_ref = INVALID_GRANT_REF;
1977	queue->rx_ring_ref = INVALID_GRANT_REF;
1978	queue->rx.sring = NULL;
1979	queue->tx.sring = NULL;
1980
1981	err = xenbus_setup_ring(dev, GFP_NOIO | __GFP_HIGH, vaddr: (void **)&txs,
1982	nr_pages: 1, grefs: &queue->tx_ring_ref);
1983	if (err)
1984	goto fail;
1985
1986	XEN_FRONT_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);
1987
1988	err = xenbus_setup_ring(dev, GFP_NOIO | __GFP_HIGH, vaddr: (void **)&rxs,
1989	nr_pages: 1, grefs: &queue->rx_ring_ref);
1990	if (err)
1991	goto fail;
1992
1993	XEN_FRONT_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
1994
1995	if (feature_split_evtchn)
1996	err = setup_netfront_split(queue);
1997	/* setup single event channel if
1998	* a) feature-split-event-channels == 0
1999	* b) feature-split-event-channels == 1 but failed to setup
2000	*/
2001	if (!feature_split_evtchn || err)
2002	err = setup_netfront_single(queue);
2003
2004	if (err)
2005	goto fail;
2006
2007	return 0;
2008
2009	fail:
2010	xenbus_teardown_ring(vaddr: (void **)&queue->rx.sring, nr_pages: 1, grefs: &queue->rx_ring_ref);
2011	xenbus_teardown_ring(vaddr: (void **)&queue->tx.sring, nr_pages: 1, grefs: &queue->tx_ring_ref);
2012
2013	return err;
2014	}
2015
2016	/* Queue-specific initialisation
2017	* This used to be done in xennet_create_dev() but must now
2018	* be run per-queue.
2019	*/
2020	static int xennet_init_queue(struct netfront_queue *queue)
2021	{
2022	unsigned short i;
2023	int err = 0;
2024	char *devid;
2025
2026	spin_lock_init(&queue->tx_lock);
2027	spin_lock_init(&queue->rx_lock);
2028	spin_lock_init(&queue->rx_cons_lock);
2029
2030	timer_setup(&queue->rx_refill_timer, rx_refill_timeout, 0);
2031
2032	devid = strrchr(queue->info->xbdev->nodename, '/') + 1;
2033	snprintf(buf: queue->name, size: sizeof(queue->name), fmt: "vif%s-q%u",
2034	devid, queue->id);
2035
2036	/* Initialise tx_skb_freelist as a free chain containing every entry. */
2037	queue->tx_skb_freelist = 0;
2038	queue->tx_pend_queue = TX_LINK_NONE;
2039	for (i = 0; i < NET_TX_RING_SIZE; i++) {
2040	queue->tx_link[i] = i + 1;
2041	queue->grant_tx_ref[i] = INVALID_GRANT_REF;
2042	queue->grant_tx_page[i] = NULL;
2043	}
2044	queue->tx_link[NET_TX_RING_SIZE - 1] = TX_LINK_NONE;
2045
2046	/* Clear out rx_skbs */
2047	for (i = 0; i < NET_RX_RING_SIZE; i++) {
2048	queue->rx_skbs[i] = NULL;
2049	queue->grant_rx_ref[i] = INVALID_GRANT_REF;
2050	}
2051
2052	/* A grant for every tx ring slot */
2053	if (gnttab_alloc_grant_references(NET_TX_RING_SIZE,
2054	pprivate_head: &queue->gref_tx_head) < 0) {
2055	pr_alert("can't alloc tx grant refs\n");
2056	err = -ENOMEM;
2057	goto exit;
2058	}
2059
2060	/* A grant for every rx ring slot */
2061	if (gnttab_alloc_grant_references(NET_RX_RING_SIZE,
2062	pprivate_head: &queue->gref_rx_head) < 0) {
2063	pr_alert("can't alloc rx grant refs\n");
2064	err = -ENOMEM;
2065	goto exit_free_tx;
2066	}
2067
2068	return 0;
2069
2070	exit_free_tx:
2071	gnttab_free_grant_references(head: queue->gref_tx_head);
2072	exit:
2073	return err;
2074	}
2075
2076	static int write_queue_xenstore_keys(struct netfront_queue *queue,
2077	struct xenbus_transaction *xbt, int write_hierarchical)
2078	{
2079	/* Write the queue-specific keys into XenStore in the traditional
2080	* way for a single queue, or in a queue subkeys for multiple
2081	* queues.
2082	*/
2083	struct xenbus_device *dev = queue->info->xbdev;
2084	int err;
2085	const char *message;
2086	char *path;
2087	size_t pathsize;
2088
2089	/* Choose the correct place to write the keys */
2090	if (write_hierarchical) {
2091	pathsize = strlen(dev->nodename) + 10;
2092	path = kzalloc(size: pathsize, GFP_KERNEL);
2093	if (!path) {
2094	err = -ENOMEM;
2095	message = "out of memory while writing ring references";
2096	goto error;
2097	}
2098	snprintf(buf: path, size: pathsize, fmt: "%s/queue-%u",
2099	dev->nodename, queue->id);
2100	} else {
2101	path = (char *)dev->nodename;
2102	}
2103
2104	/* Write ring references */
2105	err = xenbus_printf(t: *xbt, dir: path, node: "tx-ring-ref", fmt: "%u",
2106	queue->tx_ring_ref);
2107	if (err) {
2108	message = "writing tx-ring-ref";
2109	goto error;
2110	}
2111
2112	err = xenbus_printf(t: *xbt, dir: path, node: "rx-ring-ref", fmt: "%u",
2113	queue->rx_ring_ref);
2114	if (err) {
2115	message = "writing rx-ring-ref";
2116	goto error;
2117	}
2118
2119	/* Write event channels; taking into account both shared
2120	* and split event channel scenarios.
2121	*/
2122	if (queue->tx_evtchn == queue->rx_evtchn) {
2123	/* Shared event channel */
2124	err = xenbus_printf(t: *xbt, dir: path,
2125	node: "event-channel", fmt: "%u", queue->tx_evtchn);
2126	if (err) {
2127	message = "writing event-channel";
2128	goto error;
2129	}
2130	} else {
2131	/* Split event channels */
2132	err = xenbus_printf(t: *xbt, dir: path,
2133	node: "event-channel-tx", fmt: "%u", queue->tx_evtchn);
2134	if (err) {
2135	message = "writing event-channel-tx";
2136	goto error;
2137	}
2138
2139	err = xenbus_printf(t: *xbt, dir: path,
2140	node: "event-channel-rx", fmt: "%u", queue->rx_evtchn);
2141	if (err) {
2142	message = "writing event-channel-rx";
2143	goto error;
2144	}
2145	}
2146
2147	if (write_hierarchical)
2148	kfree(objp: path);
2149	return 0;
2150
2151	error:
2152	if (write_hierarchical)
2153	kfree(objp: path);
2154	xenbus_dev_fatal(dev, err, fmt: "%s", message);
2155	return err;
2156	}
2157
2158
2159
2160	static int xennet_create_page_pool(struct netfront_queue *queue)
2161	{
2162	int err;
2163	struct page_pool_params pp_params = {
2164	.order = 0,
2165	.flags = 0,
2166	.pool_size = NET_RX_RING_SIZE,
2167	.nid = NUMA_NO_NODE,
2168	.dev = &queue->info->netdev->dev,
2169	.offset = XDP_PACKET_HEADROOM,
2170	.max_len = XEN_PAGE_SIZE - XDP_PACKET_HEADROOM,
2171	};
2172
2173	queue->page_pool = page_pool_create(params: &pp_params);
2174	if (IS_ERR(ptr: queue->page_pool)) {
2175	err = PTR_ERR(ptr: queue->page_pool);
2176	queue->page_pool = NULL;
2177	return err;
2178	}
2179
2180	err = xdp_rxq_info_reg(xdp_rxq: &queue->xdp_rxq, dev: queue->info->netdev,
2181	queue_index: queue->id, napi_id: 0);
2182	if (err) {
2183	netdev_err(dev: queue->info->netdev, format: "xdp_rxq_info_reg failed\n");
2184	goto err_free_pp;
2185	}
2186
2187	err = xdp_rxq_info_reg_mem_model(xdp_rxq: &queue->xdp_rxq,
2188	type: MEM_TYPE_PAGE_POOL, allocator: queue->page_pool);
2189	if (err) {
2190	netdev_err(dev: queue->info->netdev, format: "xdp_rxq_info_reg_mem_model failed\n");
2191	goto err_unregister_rxq;
2192	}
2193	return 0;
2194
2195	err_unregister_rxq:
2196	xdp_rxq_info_unreg(xdp_rxq: &queue->xdp_rxq);
2197	err_free_pp:
2198	page_pool_destroy(pool: queue->page_pool);
2199	queue->page_pool = NULL;
2200	return err;
2201	}
2202
2203	static int xennet_create_queues(struct netfront_info *info,
2204	unsigned int *num_queues)
2205	{
2206	unsigned int i;
2207	int ret;
2208
2209	info->queues = kcalloc(n: *num_queues, size: sizeof(struct netfront_queue),
2210	GFP_KERNEL);
2211	if (!info->queues)
2212	return -ENOMEM;
2213
2214	for (i = 0; i < *num_queues; i++) {
2215	struct netfront_queue *queue = &info->queues[i];
2216
2217	queue->id = i;
2218	queue->info = info;
2219
2220	ret = xennet_init_queue(queue);
2221	if (ret < 0) {
2222	dev_warn(&info->xbdev->dev,
2223	"only created %d queues\n", i);
2224	*num_queues = i;
2225	break;
2226	}
2227
2228	/* use page pool recycling instead of buddy allocator */
2229	ret = xennet_create_page_pool(queue);
2230	if (ret < 0) {
2231	dev_err(&info->xbdev->dev, "can't allocate page pool\n");
2232	*num_queues = i;
2233	return ret;
2234	}
2235
2236	netif_napi_add(dev: queue->info->netdev, napi: &queue->napi, poll: xennet_poll);
2237	if (netif_running(dev: info->netdev))
2238	napi_enable(n: &queue->napi);
2239	}
2240
2241	netif_set_real_num_tx_queues(dev: info->netdev, txq: *num_queues);
2242
2243	if (*num_queues == 0) {
2244	dev_err(&info->xbdev->dev, "no queues\n");
2245	return -EINVAL;
2246	}
2247	return 0;
2248	}
2249
2250	/* Common code used when first setting up, and when resuming. */
2251	static int talk_to_netback(struct xenbus_device *dev,
2252	struct netfront_info *info)
2253	{
2254	const char *message;
2255	struct xenbus_transaction xbt;
2256	int err;
2257	unsigned int feature_split_evtchn;
2258	unsigned int i = 0;
2259	unsigned int max_queues = 0;
2260	struct netfront_queue *queue = NULL;
2261	unsigned int num_queues = 1;
2262	u8 addr[ETH_ALEN];
2263
2264	info->netdev->irq = 0;
2265
2266	/* Check if backend is trusted. */
2267	info->bounce = !xennet_trusted ||
2268	!xenbus_read_unsigned(dir: dev->nodename, node: "trusted", default_val: 1);
2269
2270	/* Check if backend supports multiple queues */
2271	max_queues = xenbus_read_unsigned(dir: info->xbdev->otherend,
2272	node: "multi-queue-max-queues", default_val: 1);
2273	num_queues = min(max_queues, xennet_max_queues);
2274
2275	/* Check feature-split-event-channels */
2276	feature_split_evtchn = xenbus_read_unsigned(dir: info->xbdev->otherend,
2277	node: "feature-split-event-channels", default_val: 0);
2278
2279	/* Read mac addr. */
2280	err = xen_net_read_mac(dev, mac: addr);
2281	if (err) {
2282	xenbus_dev_fatal(dev, err, fmt: "parsing %s/mac", dev->nodename);
2283	goto out_unlocked;
2284	}
2285	eth_hw_addr_set(dev: info->netdev, addr);
2286
2287	info->netback_has_xdp_headroom = xenbus_read_unsigned(dir: info->xbdev->otherend,
2288	node: "feature-xdp-headroom", default_val: 0);
2289	if (info->netback_has_xdp_headroom) {
2290	/* set the current xen-netfront xdp state */
2291	err = talk_to_netback_xdp(np: info, xdp: info->netfront_xdp_enabled ?
2292	NETBACK_XDP_HEADROOM_ENABLE :
2293	NETBACK_XDP_HEADROOM_DISABLE);
2294	if (err)
2295	goto out_unlocked;
2296	}
2297
2298	rtnl_lock();
2299	if (info->queues)
2300	xennet_destroy_queues(info);
2301
2302	/* For the case of a reconnect reset the "broken" indicator. */
2303	info->broken = false;
2304
2305	err = xennet_create_queues(info, num_queues: &num_queues);
2306	if (err < 0) {
2307	xenbus_dev_fatal(dev, err, fmt: "creating queues");
2308	kfree(objp: info->queues);
2309	info->queues = NULL;
2310	goto out;
2311	}
2312	rtnl_unlock();
2313
2314	/* Create shared ring, alloc event channel -- for each queue */
2315	for (i = 0; i < num_queues; ++i) {
2316	queue = &info->queues[i];
2317	err = setup_netfront(dev, queue, feature_split_evtchn);
2318	if (err)
2319	goto destroy_ring;
2320	}
2321
2322	again:
2323	err = xenbus_transaction_start(t: &xbt);
2324	if (err) {
2325	xenbus_dev_fatal(dev, err, fmt: "starting transaction");
2326	goto destroy_ring;
2327	}
2328
2329	if (xenbus_exists(XBT_NIL,
2330	dir: info->xbdev->otherend, node: "multi-queue-max-queues")) {
2331	/* Write the number of queues */
2332	err = xenbus_printf(xbt, dev->nodename,
2333	"multi-queue-num-queues", "%u", num_queues);
2334	if (err) {
2335	message = "writing multi-queue-num-queues";
2336	goto abort_transaction_no_dev_fatal;
2337	}
2338	}
2339
2340	if (num_queues == 1) {
2341	err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */
2342	if (err)
2343	goto abort_transaction_no_dev_fatal;
2344	} else {
2345	/* Write the keys for each queue */
2346	for (i = 0; i < num_queues; ++i) {
2347	queue = &info->queues[i];
2348	err = write_queue_xenstore_keys(queue, &xbt, 1); /* hierarchical */
2349	if (err)
2350	goto abort_transaction_no_dev_fatal;
2351	}
2352	}
2353
2354	/* The remaining keys are not queue-specific */
2355	err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
2356	1);
2357	if (err) {
2358	message = "writing request-rx-copy";
2359	goto abort_transaction;
2360	}
2361
2362	err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1);
2363	if (err) {
2364	message = "writing feature-rx-notify";
2365	goto abort_transaction;
2366	}
2367
2368	err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1);
2369	if (err) {
2370	message = "writing feature-sg";
2371	goto abort_transaction;
2372	}
2373
2374	err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1);
2375	if (err) {
2376	message = "writing feature-gso-tcpv4";
2377	goto abort_transaction;
2378	}
2379
2380	err = xenbus_write(xbt, dev->nodename, "feature-gso-tcpv6", "1");
2381	if (err) {
2382	message = "writing feature-gso-tcpv6";
2383	goto abort_transaction;
2384	}
2385
2386	err = xenbus_write(xbt, dev->nodename, "feature-ipv6-csum-offload",
2387	"1");
2388	if (err) {
2389	message = "writing feature-ipv6-csum-offload";
2390	goto abort_transaction;
2391	}
2392
2393	err = xenbus_transaction_end(xbt, 0);
2394	if (err) {
2395	if (err == -EAGAIN)
2396	goto again;
2397	xenbus_dev_fatal(dev, err, "completing transaction");
2398	goto destroy_ring;
2399	}
2400
2401	return 0;
2402
2403	abort_transaction:
2404	xenbus_dev_fatal(dev, err, "%s", message);
2405	abort_transaction_no_dev_fatal:
2406	xenbus_transaction_end(xbt, 1);
2407	destroy_ring:
2408	xennet_disconnect_backend(info);
2409	rtnl_lock();
2410	xennet_destroy_queues(info);
2411	out:
2412	rtnl_unlock();
2413	out_unlocked:
2414	device_unregister(&dev->dev);
2415	return err;
2416	}
2417
2418	static int xennet_connect(struct net_device *dev)
2419	{
2420	struct netfront_info *np = netdev_priv(dev);
2421	unsigned int num_queues = 0;
2422	int err;
2423	unsigned int j = 0;
2424	struct netfront_queue *queue = NULL;
2425
2426	if (!xenbus_read_unsigned(dir: np->xbdev->otherend, node: "feature-rx-copy", default_val: 0)) {
2427	dev_info(&dev->dev,
2428	"backend does not support copying receive path\n");
2429	return -ENODEV;
2430	}
2431
2432	err = talk_to_netback(dev: np->xbdev, info: np);
2433	if (err)
2434	return err;
2435	if (np->netback_has_xdp_headroom)
2436	pr_info("backend supports XDP headroom\n");
2437	if (np->bounce)
2438	dev_info(&np->xbdev->dev,
2439	"bouncing transmitted data to zeroed pages\n");
2440
2441	/* talk_to_netback() sets the correct number of queues */
2442	num_queues = dev->real_num_tx_queues;
2443
2444	if (dev->reg_state == NETREG_UNINITIALIZED) {
2445	err = register_netdev(dev);
2446	if (err) {
2447	pr_warn("%s: register_netdev err=%d\n", __func__, err);
2448	device_unregister(dev: &np->xbdev->dev);
2449	return err;
2450	}
2451	}
2452
2453	rtnl_lock();
2454	netdev_update_features(dev);
2455	rtnl_unlock();
2456
2457	/*
2458	* All public and private state should now be sane. Get
2459	* ready to start sending and receiving packets and give the driver
2460	* domain a kick because we've probably just requeued some
2461	* packets.
2462	*/
2463	netif_tx_lock_bh(dev: np->netdev);
2464	netif_device_attach(dev: np->netdev);
2465	netif_tx_unlock_bh(dev: np->netdev);
2466
2467	netif_carrier_on(dev: np->netdev);
2468	for (j = 0; j < num_queues; ++j) {
2469	queue = &np->queues[j];
2470
2471	notify_remote_via_irq(irq: queue->tx_irq);
2472	if (queue->tx_irq != queue->rx_irq)
2473	notify_remote_via_irq(irq: queue->rx_irq);
2474
2475	spin_lock_bh(lock: &queue->rx_lock);
2476	xennet_alloc_rx_buffers(queue);
2477	spin_unlock_bh(lock: &queue->rx_lock);
2478	}
2479
2480	return 0;
2481	}
2482
2483	/*
2484	* Callback received when the backend's state changes.
2485	*/
2486	static void netback_changed(struct xenbus_device *dev,
2487	enum xenbus_state backend_state)
2488	{
2489	struct netfront_info *np = dev_get_drvdata(dev: &dev->dev);
2490	struct net_device *netdev = np->netdev;
2491
2492	dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));
2493
2494	wake_up_all(&module_wq);
2495
2496	switch (backend_state) {
2497	case XenbusStateInitialising:
2498	case XenbusStateInitialised:
2499	case XenbusStateReconfiguring:
2500	case XenbusStateReconfigured:
2501	case XenbusStateUnknown:
2502	break;
2503
2504	case XenbusStateInitWait:
2505	if (dev->state != XenbusStateInitialising)
2506	break;
2507	if (xennet_connect(dev: netdev) != 0)
2508	break;
2509	xenbus_switch_state(dev, new_state: XenbusStateConnected);
2510	break;
2511
2512	case XenbusStateConnected:
2513	netdev_notify_peers(dev: netdev);
2514	break;
2515
2516	case XenbusStateClosed:
2517	if (dev->state == XenbusStateClosed)
2518	break;
2519	fallthrough; /* Missed the backend's CLOSING state */
2520	case XenbusStateClosing:
2521	xenbus_frontend_closed(dev);
2522	break;
2523	}
2524	}
2525
2526	static const struct xennet_stat {
2527	char name[ETH_GSTRING_LEN];
2528	u16 offset;
2529	} xennet_stats[] = {
2530	{
2531	"rx_gso_checksum_fixup",
2532	offsetof(struct netfront_info, rx_gso_checksum_fixup)
2533	},
2534	};
2535
2536	static int xennet_get_sset_count(struct net_device *dev, int string_set)
2537	{
2538	switch (string_set) {
2539	case ETH_SS_STATS:
2540	return ARRAY_SIZE(xennet_stats);
2541	default:
2542	return -EINVAL;
2543	}
2544	}
2545
2546	static void xennet_get_ethtool_stats(struct net_device *dev,
2547	struct ethtool_stats *stats, u64 * data)
2548	{
2549	void *np = netdev_priv(dev);
2550	int i;
2551
2552	for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2553	data[i] = atomic_read(v: (atomic_t *)(np + xennet_stats[i].offset));
2554	}
2555
2556	static void xennet_get_strings(struct net_device *dev, u32 stringset, u8 * data)
2557	{
2558	int i;
2559
2560	switch (stringset) {
2561	case ETH_SS_STATS:
2562	for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2563	memcpy(data + i * ETH_GSTRING_LEN,
2564	xennet_stats[i].name, ETH_GSTRING_LEN);
2565	break;
2566	}
2567	}
2568
2569	static const struct ethtool_ops xennet_ethtool_ops =
2570	{
2571	.get_link = ethtool_op_get_link,
2572
2573	.get_sset_count = xennet_get_sset_count,
2574	.get_ethtool_stats = xennet_get_ethtool_stats,
2575	.get_strings = xennet_get_strings,
2576	.get_ts_info = ethtool_op_get_ts_info,
2577	};
2578
2579	#ifdef CONFIG_SYSFS
2580	static ssize_t show_rxbuf(struct device *dev,
2581	struct device_attribute *attr, char *buf)
2582	{
2583	return sprintf(buf, fmt: "%lu\n", NET_RX_RING_SIZE);
2584	}
2585
2586	static ssize_t store_rxbuf(struct device *dev,
2587	struct device_attribute *attr,
2588	const char *buf, size_t len)
2589	{
2590	char *endp;
2591
2592	if (!capable(CAP_NET_ADMIN))
2593	return -EPERM;
2594
2595	simple_strtoul(buf, &endp, 0);
2596	if (endp == buf)
2597	return -EBADMSG;
2598
2599	/* rxbuf_min and rxbuf_max are no longer configurable. */
2600
2601	return len;
2602	}
2603
2604	static DEVICE_ATTR(rxbuf_min, 0644, show_rxbuf, store_rxbuf);
2605	static DEVICE_ATTR(rxbuf_max, 0644, show_rxbuf, store_rxbuf);
2606	static DEVICE_ATTR(rxbuf_cur, 0444, show_rxbuf, NULL);
2607
2608	static struct attribute *xennet_dev_attrs[] = {
2609	&dev_attr_rxbuf_min.attr,
2610	&dev_attr_rxbuf_max.attr,
2611	&dev_attr_rxbuf_cur.attr,
2612	NULL
2613	};
2614
2615	static const struct attribute_group xennet_dev_group = {
2616	.attrs = xennet_dev_attrs
2617	};
2618	#endif /* CONFIG_SYSFS */
2619
2620	static void xennet_bus_close(struct xenbus_device *dev)
2621	{
2622	int ret;
2623
2624	if (xenbus_read_driver_state(path: dev->otherend) == XenbusStateClosed)
2625	return;
2626	do {
2627	xenbus_switch_state(dev, new_state: XenbusStateClosing);
2628	ret = wait_event_timeout(module_wq,
2629	xenbus_read_driver_state(dev->otherend) ==
2630	XenbusStateClosing ||
2631	xenbus_read_driver_state(dev->otherend) ==
2632	XenbusStateClosed ||
2633	xenbus_read_driver_state(dev->otherend) ==
2634	XenbusStateUnknown,
2635	XENNET_TIMEOUT);
2636	} while (!ret);
2637
2638	if (xenbus_read_driver_state(path: dev->otherend) == XenbusStateClosed)
2639	return;
2640
2641	do {
2642	xenbus_switch_state(dev, new_state: XenbusStateClosed);
2643	ret = wait_event_timeout(module_wq,
2644	xenbus_read_driver_state(dev->otherend) ==
2645	XenbusStateClosed ||
2646	xenbus_read_driver_state(dev->otherend) ==
2647	XenbusStateUnknown,
2648	XENNET_TIMEOUT);
2649	} while (!ret);
2650	}
2651
2652	static void xennet_remove(struct xenbus_device *dev)
2653	{
2654	struct netfront_info *info = dev_get_drvdata(dev: &dev->dev);
2655
2656	xennet_bus_close(dev);
2657	xennet_disconnect_backend(info);
2658
2659	if (info->netdev->reg_state == NETREG_REGISTERED)
2660	unregister_netdev(dev: info->netdev);
2661
2662	if (info->queues) {
2663	rtnl_lock();
2664	xennet_destroy_queues(info);
2665	rtnl_unlock();
2666	}
2667	xennet_free_netdev(netdev: info->netdev);
2668	}
2669
2670	static const struct xenbus_device_id netfront_ids[] = {
2671	{ "vif" },
2672	{ "" }
2673	};
2674
2675	static struct xenbus_driver netfront_driver = {
2676	.ids = netfront_ids,
2677	.probe = netfront_probe,
2678	.remove = xennet_remove,
2679	.resume = netfront_resume,
2680	.otherend_changed = netback_changed,
2681	};
2682
2683	static int __init netif_init(void)
2684	{
2685	if (!xen_domain())
2686	return -ENODEV;
2687
2688	if (!xen_has_pv_nic_devices())
2689	return -ENODEV;
2690
2691	pr_info("Initialising Xen virtual ethernet driver\n");
2692
2693	/* Allow as many queues as there are CPUs inut max. 8 if user has not
2694	* specified a value.
2695	*/
2696	if (xennet_max_queues == 0)
2697	xennet_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
2698	num_online_cpus());
2699
2700	return xenbus_register_frontend(&netfront_driver);
2701	}
2702	module_init(netif_init);
2703
2704
2705	static void __exit netif_exit(void)
2706	{
2707	xenbus_unregister_driver(drv: &netfront_driver);
2708	}
2709	module_exit(netif_exit);
2710
2711	MODULE_DESCRIPTION("Xen virtual network device frontend");
2712	MODULE_LICENSE("GPL");
2713	MODULE_ALIAS("xen:vif");
2714	MODULE_ALIAS("xennet");
2715