1 /* A simple network driver using virtio.
3 * Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 #include <linux/netdevice.h>
21 #include <linux/etherdevice.h>
22 #include <linux/ethtool.h>
23 #include <linux/module.h>
24 #include <linux/virtio.h>
25 #include <linux/virtio_net.h>
26 #include <linux/scatterlist.h>
28 static int napi_weight
= 128;
29 module_param(napi_weight
, int, 0444);
31 static int csum
= 1, gso
= 1;
32 module_param(csum
, bool, 0444);
33 module_param(gso
, bool, 0444);
35 /* FIXME: MTU in config. */
36 #define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN)
40 struct virtio_device
*vdev
;
41 struct virtqueue
*rvq
, *svq
;
42 struct net_device
*dev
;
43 struct napi_struct napi
;
45 /* The skb we couldn't send because buffers were full. */
46 struct sk_buff
*last_xmit_skb
;
48 /* If we need to free in a timer, this is it. */
49 struct timer_list xmit_free_timer
;
51 /* Number of input buffers, and max we've ever had. */
52 unsigned int num
, max
;
54 /* For cleaning up after transmission. */
55 struct tasklet_struct tasklet
;
58 /* Receive & send queues. */
59 struct sk_buff_head recv
;
60 struct sk_buff_head send
;
63 static inline struct virtio_net_hdr
*skb_vnet_hdr(struct sk_buff
*skb
)
65 return (struct virtio_net_hdr
*)skb
->cb
;
68 static inline void vnet_hdr_to_sg(struct scatterlist
*sg
, struct sk_buff
*skb
)
70 sg_init_one(sg
, skb_vnet_hdr(skb
), sizeof(struct virtio_net_hdr
));
73 static void skb_xmit_done(struct virtqueue
*svq
)
75 struct virtnet_info
*vi
= svq
->vdev
->priv
;
77 /* Suppress further interrupts. */
78 svq
->vq_ops
->disable_cb(svq
);
80 /* We were probably waiting for more output buffers. */
81 netif_wake_queue(vi
->dev
);
83 /* Make sure we re-xmit last_xmit_skb: if there are no more packets
84 * queued, start_xmit won't be called. */
85 tasklet_schedule(&vi
->tasklet
);
88 static void receive_skb(struct net_device
*dev
, struct sk_buff
*skb
,
91 struct virtio_net_hdr
*hdr
= skb_vnet_hdr(skb
);
93 if (unlikely(len
< sizeof(struct virtio_net_hdr
) + ETH_HLEN
)) {
94 pr_debug("%s: short packet %i\n", dev
->name
, len
);
95 dev
->stats
.rx_length_errors
++;
98 len
-= sizeof(struct virtio_net_hdr
);
99 BUG_ON(len
> MAX_PACKET_LEN
);
103 dev
->stats
.rx_bytes
+= skb
->len
;
104 dev
->stats
.rx_packets
++;
106 if (hdr
->flags
& VIRTIO_NET_HDR_F_NEEDS_CSUM
) {
107 pr_debug("Needs csum!\n");
108 if (!skb_partial_csum_set(skb
,hdr
->csum_start
,hdr
->csum_offset
))
112 skb
->protocol
= eth_type_trans(skb
, dev
);
113 pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
114 ntohs(skb
->protocol
), skb
->len
, skb
->pkt_type
);
116 if (hdr
->gso_type
!= VIRTIO_NET_HDR_GSO_NONE
) {
118 switch (hdr
->gso_type
& ~VIRTIO_NET_HDR_GSO_ECN
) {
119 case VIRTIO_NET_HDR_GSO_TCPV4
:
120 skb_shinfo(skb
)->gso_type
= SKB_GSO_TCPV4
;
122 case VIRTIO_NET_HDR_GSO_UDP
:
123 skb_shinfo(skb
)->gso_type
= SKB_GSO_UDP
;
125 case VIRTIO_NET_HDR_GSO_TCPV6
:
126 skb_shinfo(skb
)->gso_type
= SKB_GSO_TCPV6
;
130 printk(KERN_WARNING
"%s: bad gso type %u.\n",
131 dev
->name
, hdr
->gso_type
);
135 if (hdr
->gso_type
& VIRTIO_NET_HDR_GSO_ECN
)
136 skb_shinfo(skb
)->gso_type
|= SKB_GSO_TCP_ECN
;
138 skb_shinfo(skb
)->gso_size
= hdr
->gso_size
;
139 if (skb_shinfo(skb
)->gso_size
== 0) {
141 printk(KERN_WARNING
"%s: zero gso size.\n",
146 /* Header must be checked, and gso_segs computed. */
147 skb_shinfo(skb
)->gso_type
|= SKB_GSO_DODGY
;
148 skb_shinfo(skb
)->gso_segs
= 0;
151 netif_receive_skb(skb
);
155 dev
->stats
.rx_frame_errors
++;
160 static void try_fill_recv(struct virtnet_info
*vi
)
163 struct scatterlist sg
[2+MAX_SKB_FRAGS
];
166 sg_init_table(sg
, 2+MAX_SKB_FRAGS
);
168 skb
= netdev_alloc_skb(vi
->dev
, MAX_PACKET_LEN
);
172 skb_put(skb
, MAX_PACKET_LEN
);
173 vnet_hdr_to_sg(sg
, skb
);
174 num
= skb_to_sgvec(skb
, sg
+1, 0, skb
->len
) + 1;
175 skb_queue_head(&vi
->recv
, skb
);
177 err
= vi
->rvq
->vq_ops
->add_buf(vi
->rvq
, sg
, 0, num
, skb
);
179 skb_unlink(skb
, &vi
->recv
);
185 if (unlikely(vi
->num
> vi
->max
))
187 vi
->rvq
->vq_ops
->kick(vi
->rvq
);
190 static void skb_recv_done(struct virtqueue
*rvq
)
192 struct virtnet_info
*vi
= rvq
->vdev
->priv
;
193 /* Schedule NAPI, Suppress further interrupts if successful. */
194 if (netif_rx_schedule_prep(vi
->dev
, &vi
->napi
)) {
195 rvq
->vq_ops
->disable_cb(rvq
);
196 __netif_rx_schedule(vi
->dev
, &vi
->napi
);
200 static int virtnet_poll(struct napi_struct
*napi
, int budget
)
202 struct virtnet_info
*vi
= container_of(napi
, struct virtnet_info
, napi
);
203 struct sk_buff
*skb
= NULL
;
204 unsigned int len
, received
= 0;
207 while (received
< budget
&&
208 (skb
= vi
->rvq
->vq_ops
->get_buf(vi
->rvq
, &len
)) != NULL
) {
209 __skb_unlink(skb
, &vi
->recv
);
210 receive_skb(vi
->dev
, skb
, len
);
215 /* FIXME: If we oom and completely run out of inbufs, we need
216 * to start a timer trying to fill more. */
217 if (vi
->num
< vi
->max
/ 2)
220 /* Out of packets? */
221 if (received
< budget
) {
222 netif_rx_complete(vi
->dev
, napi
);
223 if (unlikely(!vi
->rvq
->vq_ops
->enable_cb(vi
->rvq
))
224 && napi_schedule_prep(napi
)) {
225 vi
->rvq
->vq_ops
->disable_cb(vi
->rvq
);
226 __netif_rx_schedule(vi
->dev
, napi
);
234 static void free_old_xmit_skbs(struct virtnet_info
*vi
)
239 while ((skb
= vi
->svq
->vq_ops
->get_buf(vi
->svq
, &len
)) != NULL
) {
240 pr_debug("Sent skb %p\n", skb
);
241 __skb_unlink(skb
, &vi
->send
);
242 vi
->dev
->stats
.tx_bytes
+= skb
->len
;
243 vi
->dev
->stats
.tx_packets
++;
248 /* If the virtio transport doesn't always notify us when all in-flight packets
249 * are consumed, we fall back to using this function on a timer to free them. */
250 static void xmit_free(unsigned long data
)
252 struct virtnet_info
*vi
= (void *)data
;
254 netif_tx_lock(vi
->dev
);
256 free_old_xmit_skbs(vi
);
258 if (!skb_queue_empty(&vi
->send
))
259 mod_timer(&vi
->xmit_free_timer
, jiffies
+ (HZ
/10));
261 netif_tx_unlock(vi
->dev
);
264 static int xmit_skb(struct virtnet_info
*vi
, struct sk_buff
*skb
)
267 struct scatterlist sg
[2+MAX_SKB_FRAGS
];
268 struct virtio_net_hdr
*hdr
;
269 const unsigned char *dest
= ((struct ethhdr
*)skb
->data
)->h_dest
;
271 sg_init_table(sg
, 2+MAX_SKB_FRAGS
);
273 pr_debug("%s: xmit %p " MAC_FMT
"\n", vi
->dev
->name
, skb
,
274 dest
[0], dest
[1], dest
[2],
275 dest
[3], dest
[4], dest
[5]);
277 /* Encode metadata header at front. */
278 hdr
= skb_vnet_hdr(skb
);
279 if (skb
->ip_summed
== CHECKSUM_PARTIAL
) {
280 hdr
->flags
= VIRTIO_NET_HDR_F_NEEDS_CSUM
;
281 hdr
->csum_start
= skb
->csum_start
- skb_headroom(skb
);
282 hdr
->csum_offset
= skb
->csum_offset
;
285 hdr
->csum_offset
= hdr
->csum_start
= 0;
288 if (skb_is_gso(skb
)) {
289 hdr
->hdr_len
= skb_transport_header(skb
) - skb
->data
;
290 hdr
->gso_size
= skb_shinfo(skb
)->gso_size
;
291 if (skb_shinfo(skb
)->gso_type
& SKB_GSO_TCPV4
)
292 hdr
->gso_type
= VIRTIO_NET_HDR_GSO_TCPV4
;
293 else if (skb_shinfo(skb
)->gso_type
& SKB_GSO_TCPV6
)
294 hdr
->gso_type
= VIRTIO_NET_HDR_GSO_TCPV6
;
295 else if (skb_shinfo(skb
)->gso_type
& SKB_GSO_UDP
)
296 hdr
->gso_type
= VIRTIO_NET_HDR_GSO_UDP
;
299 if (skb_shinfo(skb
)->gso_type
& SKB_GSO_TCP_ECN
)
300 hdr
->gso_type
|= VIRTIO_NET_HDR_GSO_ECN
;
302 hdr
->gso_type
= VIRTIO_NET_HDR_GSO_NONE
;
303 hdr
->gso_size
= hdr
->hdr_len
= 0;
306 vnet_hdr_to_sg(sg
, skb
);
307 num
= skb_to_sgvec(skb
, sg
+1, 0, skb
->len
) + 1;
309 err
= vi
->svq
->vq_ops
->add_buf(vi
->svq
, sg
, num
, 0, skb
);
310 if (!err
&& !vi
->free_in_tasklet
)
311 mod_timer(&vi
->xmit_free_timer
, jiffies
+ (HZ
/10));
316 static void xmit_tasklet(unsigned long data
)
318 struct virtnet_info
*vi
= (void *)data
;
320 netif_tx_lock_bh(vi
->dev
);
321 if (vi
->last_xmit_skb
&& xmit_skb(vi
, vi
->last_xmit_skb
) == 0) {
322 vi
->svq
->vq_ops
->kick(vi
->svq
);
323 vi
->last_xmit_skb
= NULL
;
325 if (vi
->free_in_tasklet
)
326 free_old_xmit_skbs(vi
);
327 netif_tx_unlock_bh(vi
->dev
);
330 static int start_xmit(struct sk_buff
*skb
, struct net_device
*dev
)
332 struct virtnet_info
*vi
= netdev_priv(dev
);
335 /* Free up any pending old buffers before queueing new ones. */
336 free_old_xmit_skbs(vi
);
338 /* If we has a buffer left over from last time, send it now. */
339 if (unlikely(vi
->last_xmit_skb
) &&
340 xmit_skb(vi
, vi
->last_xmit_skb
) != 0)
343 vi
->last_xmit_skb
= NULL
;
345 /* Put new one in send queue and do transmit */
347 __skb_queue_head(&vi
->send
, skb
);
348 if (xmit_skb(vi
, skb
) != 0) {
349 vi
->last_xmit_skb
= skb
;
355 vi
->svq
->vq_ops
->kick(vi
->svq
);
359 pr_debug("%s: virtio not prepared to send\n", dev
->name
);
360 netif_stop_queue(dev
);
362 /* Activate callback for using skbs: if this returns false it
363 * means some were used in the meantime. */
364 if (unlikely(!vi
->svq
->vq_ops
->enable_cb(vi
->svq
))) {
365 vi
->svq
->vq_ops
->disable_cb(vi
->svq
);
366 netif_start_queue(dev
);
370 /* Drop this skb: we only queue one. */
371 vi
->dev
->stats
.tx_dropped
++;
377 #ifdef CONFIG_NET_POLL_CONTROLLER
378 static void virtnet_netpoll(struct net_device
*dev
)
380 struct virtnet_info
*vi
= netdev_priv(dev
);
382 napi_schedule(&vi
->napi
);
386 static int virtnet_open(struct net_device
*dev
)
388 struct virtnet_info
*vi
= netdev_priv(dev
);
390 napi_enable(&vi
->napi
);
392 /* If all buffers were filled by other side before we napi_enabled, we
393 * won't get another interrupt, so process any outstanding packets
394 * now. virtnet_poll wants re-enable the queue, so we disable here.
395 * We synchronize against interrupts via NAPI_STATE_SCHED */
396 if (netif_rx_schedule_prep(dev
, &vi
->napi
)) {
397 vi
->rvq
->vq_ops
->disable_cb(vi
->rvq
);
398 __netif_rx_schedule(dev
, &vi
->napi
);
403 static int virtnet_close(struct net_device
*dev
)
405 struct virtnet_info
*vi
= netdev_priv(dev
);
407 napi_disable(&vi
->napi
);
412 static int virtnet_set_tx_csum(struct net_device
*dev
, u32 data
)
414 struct virtnet_info
*vi
= netdev_priv(dev
);
415 struct virtio_device
*vdev
= vi
->vdev
;
417 if (data
&& !virtio_has_feature(vdev
, VIRTIO_NET_F_CSUM
))
420 return ethtool_op_set_tx_hw_csum(dev
, data
);
423 static struct ethtool_ops virtnet_ethtool_ops
= {
424 .set_tx_csum
= virtnet_set_tx_csum
,
425 .set_sg
= ethtool_op_set_sg
,
428 static int virtnet_probe(struct virtio_device
*vdev
)
431 struct net_device
*dev
;
432 struct virtnet_info
*vi
;
434 /* Allocate ourselves a network device with room for our info */
435 dev
= alloc_etherdev(sizeof(struct virtnet_info
));
439 /* Set up network device as normal. */
440 dev
->open
= virtnet_open
;
441 dev
->stop
= virtnet_close
;
442 dev
->hard_start_xmit
= start_xmit
;
443 dev
->features
= NETIF_F_HIGHDMA
;
444 #ifdef CONFIG_NET_POLL_CONTROLLER
445 dev
->poll_controller
= virtnet_netpoll
;
447 SET_ETHTOOL_OPS(dev
, &virtnet_ethtool_ops
);
448 SET_NETDEV_DEV(dev
, &vdev
->dev
);
450 /* Do we support "hardware" checksums? */
451 if (csum
&& virtio_has_feature(vdev
, VIRTIO_NET_F_CSUM
)) {
452 /* This opens up the world of extra features. */
453 dev
->features
|= NETIF_F_HW_CSUM
|NETIF_F_SG
|NETIF_F_FRAGLIST
;
454 if (gso
&& virtio_has_feature(vdev
, VIRTIO_NET_F_GSO
)) {
455 dev
->features
|= NETIF_F_TSO
| NETIF_F_UFO
456 | NETIF_F_TSO_ECN
| NETIF_F_TSO6
;
458 /* Individual feature bits: what can host handle? */
459 if (gso
&& virtio_has_feature(vdev
, VIRTIO_NET_F_HOST_TSO4
))
460 dev
->features
|= NETIF_F_TSO
;
461 if (gso
&& virtio_has_feature(vdev
, VIRTIO_NET_F_HOST_TSO6
))
462 dev
->features
|= NETIF_F_TSO6
;
463 if (gso
&& virtio_has_feature(vdev
, VIRTIO_NET_F_HOST_ECN
))
464 dev
->features
|= NETIF_F_TSO_ECN
;
465 if (gso
&& virtio_has_feature(vdev
, VIRTIO_NET_F_HOST_UFO
))
466 dev
->features
|= NETIF_F_UFO
;
469 /* Configuration may specify what MAC to use. Otherwise random. */
470 if (virtio_has_feature(vdev
, VIRTIO_NET_F_MAC
)) {
471 vdev
->config
->get(vdev
,
472 offsetof(struct virtio_net_config
, mac
),
473 dev
->dev_addr
, dev
->addr_len
);
475 random_ether_addr(dev
->dev_addr
);
477 /* Set up our device-specific information */
478 vi
= netdev_priv(dev
);
479 netif_napi_add(dev
, &vi
->napi
, virtnet_poll
, napi_weight
);
484 /* If they give us a callback when all buffers are done, we don't need
486 vi
->free_in_tasklet
= virtio_has_feature(vdev
,VIRTIO_F_NOTIFY_ON_EMPTY
);
488 /* We expect two virtqueues, receive then send. */
489 vi
->rvq
= vdev
->config
->find_vq(vdev
, 0, skb_recv_done
);
490 if (IS_ERR(vi
->rvq
)) {
491 err
= PTR_ERR(vi
->rvq
);
495 vi
->svq
= vdev
->config
->find_vq(vdev
, 1, skb_xmit_done
);
496 if (IS_ERR(vi
->svq
)) {
497 err
= PTR_ERR(vi
->svq
);
501 /* Initialize our empty receive and send queues. */
502 skb_queue_head_init(&vi
->recv
);
503 skb_queue_head_init(&vi
->send
);
505 tasklet_init(&vi
->tasklet
, xmit_tasklet
, (unsigned long)vi
);
507 if (!vi
->free_in_tasklet
)
508 setup_timer(&vi
->xmit_free_timer
, xmit_free
, (unsigned long)vi
);
510 err
= register_netdev(dev
);
512 pr_debug("virtio_net: registering device failed\n");
516 /* Last of all, set up some receive buffers. */
519 /* If we didn't even get one input buffer, we're useless. */
525 pr_debug("virtnet: registered device %s\n", dev
->name
);
529 unregister_netdev(dev
);
531 vdev
->config
->del_vq(vi
->svq
);
533 vdev
->config
->del_vq(vi
->rvq
);
539 static void virtnet_remove(struct virtio_device
*vdev
)
541 struct virtnet_info
*vi
= vdev
->priv
;
544 /* Stop all the virtqueues. */
545 vdev
->config
->reset(vdev
);
547 if (!vi
->free_in_tasklet
)
548 del_timer_sync(&vi
->xmit_free_timer
);
550 /* Free our skbs in send and recv queues, if any. */
551 while ((skb
= __skb_dequeue(&vi
->recv
)) != NULL
) {
555 __skb_queue_purge(&vi
->send
);
557 BUG_ON(vi
->num
!= 0);
559 vdev
->config
->del_vq(vi
->svq
);
560 vdev
->config
->del_vq(vi
->rvq
);
561 unregister_netdev(vi
->dev
);
562 free_netdev(vi
->dev
);
565 static struct virtio_device_id id_table
[] = {
566 { VIRTIO_ID_NET
, VIRTIO_DEV_ANY_ID
},
570 static unsigned int features
[] = {
571 VIRTIO_NET_F_CSUM
, VIRTIO_NET_F_GUEST_CSUM
,
572 VIRTIO_NET_F_GSO
, VIRTIO_NET_F_MAC
,
573 VIRTIO_NET_F_HOST_TSO4
, VIRTIO_NET_F_HOST_UFO
, VIRTIO_NET_F_HOST_TSO6
,
574 VIRTIO_NET_F_HOST_ECN
, VIRTIO_F_NOTIFY_ON_EMPTY
,
577 static struct virtio_driver virtio_net
= {
578 .feature_table
= features
,
579 .feature_table_size
= ARRAY_SIZE(features
),
580 .driver
.name
= KBUILD_MODNAME
,
581 .driver
.owner
= THIS_MODULE
,
582 .id_table
= id_table
,
583 .probe
= virtnet_probe
,
584 .remove
= __devexit_p(virtnet_remove
),
587 static int __init
init(void)
589 return register_virtio_driver(&virtio_net
);
592 static void __exit
fini(void)
594 unregister_virtio_driver(&virtio_net
);
599 MODULE_DEVICE_TABLE(virtio
, id_table
);
600 MODULE_DESCRIPTION("Virtio network driver");
601 MODULE_LICENSE("GPL");