Net driver using virtio
The network driver uses two virtqueues: one for input packets and one for output packets. This has nice locking properties (ie. we don't do any for recv vs send). TODO: 1) Big packets. 2) Multi-client devices (maybe separate driver?). 3) Resolve freeing of old xmit skbs (Christian Borntraeger) Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: netdev@vger.kernel.org
This commit is contained in:
Rusty Russell
parent
ec3d41c4db
commit
296f96fcfc
|
|
@ -3100,4 +3100,10 @@ config NETPOLL_TRAP
|
|||
config NET_POLL_CONTROLLER
|
||||
def_bool NETPOLL
|
||||
|
||||
config VIRTIO_NET
|
||||
tristate "Virtio network driver (EXPERIMENTAL)"
|
||||
depends on EXPERIMENTAL && VIRTIO
|
||||
---help---
|
||||
This is the virtual network driver for lguest. Say Y or M.
|
||||
|
||||
endif # NETDEVICES
|
||||
|
|
|
|||
|
|
@ -243,3 +243,4 @@ obj-$(CONFIG_FS_ENET) += fs_enet/
|
|||
|
||||
obj-$(CONFIG_NETXEN_NIC) += netxen/
|
||||
obj-$(CONFIG_NIU) += niu.o
|
||||
obj-$(CONFIG_VIRTIO_NET) += virtio_net.o
|
||||
|
|
|
|||
|
|
@ -0,0 +1,435 @@
|
|||
/* A simple network driver using virtio.
|
||||
*
|
||||
* Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License as published by
|
||||
* the Free Software Foundation; either version 2 of the License, or
|
||||
* (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
||||
*/
|
||||
//#define DEBUG
|
||||
#include <linux/netdevice.h>
|
||||
#include <linux/etherdevice.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/virtio.h>
|
||||
#include <linux/virtio_net.h>
|
||||
#include <linux/scatterlist.h>
|
||||
|
||||
/* FIXME: MTU in config. */
|
||||
#define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN)
|
||||
|
||||
struct virtnet_info
|
||||
{
|
||||
struct virtio_device *vdev;
|
||||
struct virtqueue *rvq, *svq;
|
||||
struct net_device *dev;
|
||||
struct napi_struct napi;
|
||||
|
||||
/* Number of input buffers, and max we've ever had. */
|
||||
unsigned int num, max;
|
||||
|
||||
/* Receive & send queues. */
|
||||
struct sk_buff_head recv;
|
||||
struct sk_buff_head send;
|
||||
};
|
||||
|
||||
static inline struct virtio_net_hdr *skb_vnet_hdr(struct sk_buff *skb)
|
||||
{
|
||||
return (struct virtio_net_hdr *)skb->cb;
|
||||
}
|
||||
|
||||
static inline void vnet_hdr_to_sg(struct scatterlist *sg, struct sk_buff *skb)
|
||||
{
|
||||
sg_init_one(sg, skb_vnet_hdr(skb), sizeof(struct virtio_net_hdr));
|
||||
}
|
||||
|
||||
static bool skb_xmit_done(struct virtqueue *rvq)
|
||||
{
|
||||
struct virtnet_info *vi = rvq->vdev->priv;
|
||||
|
||||
/* In case we were waiting for output buffers. */
|
||||
netif_wake_queue(vi->dev);
|
||||
return true;
|
||||
}
|
||||
|
||||
static void receive_skb(struct net_device *dev, struct sk_buff *skb,
|
||||
unsigned len)
|
||||
{
|
||||
struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);
|
||||
|
||||
if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
|
||||
pr_debug("%s: short packet %i\n", dev->name, len);
|
||||
dev->stats.rx_length_errors++;
|
||||
goto drop;
|
||||
}
|
||||
len -= sizeof(struct virtio_net_hdr);
|
||||
BUG_ON(len > MAX_PACKET_LEN);
|
||||
|
||||
skb_trim(skb, len);
|
||||
skb->protocol = eth_type_trans(skb, dev);
|
||||
pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
|
||||
ntohs(skb->protocol), skb->len, skb->pkt_type);
|
||||
dev->stats.rx_bytes += skb->len;
|
||||
dev->stats.rx_packets++;
|
||||
|
||||
if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
|
||||
pr_debug("Needs csum!\n");
|
||||
skb->ip_summed = CHECKSUM_PARTIAL;
|
||||
skb->csum_start = hdr->csum_start;
|
||||
skb->csum_offset = hdr->csum_offset;
|
||||
if (skb->csum_start > skb->len - 2
|
||||
|| skb->csum_offset > skb->len - 2) {
|
||||
if (net_ratelimit())
|
||||
printk(KERN_WARNING "%s: csum=%u/%u len=%u\n",
|
||||
dev->name, skb->csum_start,
|
||||
skb->csum_offset, skb->len);
|
||||
goto frame_err;
|
||||
}
|
||||
}
|
||||
|
||||
if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
|
||||
pr_debug("GSO!\n");
|
||||
switch (hdr->gso_type) {
|
||||
case VIRTIO_NET_HDR_GSO_TCPV4:
|
||||
skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
|
||||
break;
|
||||
case VIRTIO_NET_HDR_GSO_TCPV4_ECN:
|
||||
skb_shinfo(skb)->gso_type = SKB_GSO_TCP_ECN;
|
||||
break;
|
||||
case VIRTIO_NET_HDR_GSO_UDP:
|
||||
skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
|
||||
break;
|
||||
case VIRTIO_NET_HDR_GSO_TCPV6:
|
||||
skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
|
||||
break;
|
||||
default:
|
||||
if (net_ratelimit())
|
||||
printk(KERN_WARNING "%s: bad gso type %u.\n",
|
||||
dev->name, hdr->gso_type);
|
||||
goto frame_err;
|
||||
}
|
||||
|
||||
skb_shinfo(skb)->gso_size = hdr->gso_size;
|
||||
if (skb_shinfo(skb)->gso_size == 0) {
|
||||
if (net_ratelimit())
|
||||
printk(KERN_WARNING "%s: zero gso size.\n",
|
||||
dev->name);
|
||||
goto frame_err;
|
||||
}
|
||||
|
||||
/* Header must be checked, and gso_segs computed. */
|
||||
skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
|
||||
skb_shinfo(skb)->gso_segs = 0;
|
||||
}
|
||||
|
||||
netif_receive_skb(skb);
|
||||
return;
|
||||
|
||||
frame_err:
|
||||
dev->stats.rx_frame_errors++;
|
||||
drop:
|
||||
dev_kfree_skb(skb);
|
||||
}
|
||||
|
||||
static void try_fill_recv(struct virtnet_info *vi)
|
||||
{
|
||||
struct sk_buff *skb;
|
||||
struct scatterlist sg[1+MAX_SKB_FRAGS];
|
||||
int num, err;
|
||||
|
||||
for (;;) {
|
||||
skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
|
||||
if (unlikely(!skb))
|
||||
break;
|
||||
|
||||
skb_put(skb, MAX_PACKET_LEN);
|
||||
vnet_hdr_to_sg(sg, skb);
|
||||
num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
|
||||
skb_queue_head(&vi->recv, skb);
|
||||
|
||||
err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
|
||||
if (err) {
|
||||
skb_unlink(skb, &vi->recv);
|
||||
kfree_skb(skb);
|
||||
break;
|
||||
}
|
||||
vi->num++;
|
||||
}
|
||||
if (unlikely(vi->num > vi->max))
|
||||
vi->max = vi->num;
|
||||
vi->rvq->vq_ops->kick(vi->rvq);
|
||||
}
|
||||
|
||||
static bool skb_recv_done(struct virtqueue *rvq)
|
||||
{
|
||||
struct virtnet_info *vi = rvq->vdev->priv;
|
||||
netif_rx_schedule(vi->dev, &vi->napi);
|
||||
/* Suppress further interrupts. */
|
||||
return false;
|
||||
}
|
||||
|
||||
static int virtnet_poll(struct napi_struct *napi, int budget)
|
||||
{
|
||||
struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
|
||||
struct sk_buff *skb = NULL;
|
||||
unsigned int len, received = 0;
|
||||
|
||||
again:
|
||||
while (received < budget &&
|
||||
(skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
|
||||
__skb_unlink(skb, &vi->recv);
|
||||
receive_skb(vi->dev, skb, len);
|
||||
vi->num--;
|
||||
received++;
|
||||
}
|
||||
|
||||
/* FIXME: If we oom and completely run out of inbufs, we need
|
||||
* to start a timer trying to fill more. */
|
||||
if (vi->num < vi->max / 2)
|
||||
try_fill_recv(vi);
|
||||
|
||||
/* All done? */
|
||||
if (!skb) {
|
||||
netif_rx_complete(vi->dev, napi);
|
||||
if (unlikely(!vi->rvq->vq_ops->restart(vi->rvq))
|
||||
&& netif_rx_reschedule(vi->dev, napi))
|
||||
goto again;
|
||||
}
|
||||
|
||||
return received;
|
||||
}
|
||||
|
||||
static void free_old_xmit_skbs(struct virtnet_info *vi)
|
||||
{
|
||||
struct sk_buff *skb;
|
||||
unsigned int len;
|
||||
|
||||
while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
|
||||
pr_debug("Sent skb %p\n", skb);
|
||||
__skb_unlink(skb, &vi->send);
|
||||
vi->dev->stats.tx_bytes += len;
|
||||
vi->dev->stats.tx_packets++;
|
||||
kfree_skb(skb);
|
||||
}
|
||||
}
|
||||
|
||||
static int start_xmit(struct sk_buff *skb, struct net_device *dev)
|
||||
{
|
||||
struct virtnet_info *vi = netdev_priv(dev);
|
||||
int num, err;
|
||||
struct scatterlist sg[1+MAX_SKB_FRAGS];
|
||||
struct virtio_net_hdr *hdr;
|
||||
const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
|
||||
DECLARE_MAC_BUF(mac);
|
||||
|
||||
pr_debug("%s: xmit %p %s\n", dev->name, skb, print_mac(mac, dest));
|
||||
|
||||
free_old_xmit_skbs(vi);
|
||||
|
||||
/* Encode metadata header at front. */
|
||||
hdr = skb_vnet_hdr(skb);
|
||||
if (skb->ip_summed == CHECKSUM_PARTIAL) {
|
||||
hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
|
||||
hdr->csum_start = skb->csum_start - skb_headroom(skb);
|
||||
hdr->csum_offset = skb->csum_offset;
|
||||
} else {
|
||||
hdr->flags = 0;
|
||||
hdr->csum_offset = hdr->csum_start = 0;
|
||||
}
|
||||
|
||||
if (skb_is_gso(skb)) {
|
||||
hdr->gso_size = skb_shinfo(skb)->gso_size;
|
||||
if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
|
||||
hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4_ECN;
|
||||
else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
|
||||
hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
|
||||
else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
|
||||
hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
|
||||
else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
|
||||
hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
|
||||
else
|
||||
BUG();
|
||||
} else {
|
||||
hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
|
||||
hdr->gso_size = 0;
|
||||
}
|
||||
|
||||
vnet_hdr_to_sg(sg, skb);
|
||||
num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
|
||||
__skb_queue_head(&vi->send, skb);
|
||||
err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
|
||||
if (err) {
|
||||
pr_debug("%s: virtio not prepared to send\n", dev->name);
|
||||
skb_unlink(skb, &vi->send);
|
||||
netif_stop_queue(dev);
|
||||
return NETDEV_TX_BUSY;
|
||||
}
|
||||
vi->svq->vq_ops->kick(vi->svq);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int virtnet_open(struct net_device *dev)
|
||||
{
|
||||
struct virtnet_info *vi = netdev_priv(dev);
|
||||
|
||||
try_fill_recv(vi);
|
||||
|
||||
/* If we didn't even get one input buffer, we're useless. */
|
||||
if (vi->num == 0)
|
||||
return -ENOMEM;
|
||||
|
||||
napi_enable(&vi->napi);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int virtnet_close(struct net_device *dev)
|
||||
{
|
||||
struct virtnet_info *vi = netdev_priv(dev);
|
||||
struct sk_buff *skb;
|
||||
|
||||
napi_disable(&vi->napi);
|
||||
|
||||
/* networking core has neutered skb_xmit_done/skb_recv_done, so don't
|
||||
* worry about races vs. get(). */
|
||||
vi->rvq->vq_ops->shutdown(vi->rvq);
|
||||
while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
|
||||
kfree_skb(skb);
|
||||
vi->num--;
|
||||
}
|
||||
vi->svq->vq_ops->shutdown(vi->svq);
|
||||
while ((skb = __skb_dequeue(&vi->send)) != NULL)
|
||||
kfree_skb(skb);
|
||||
|
||||
BUG_ON(vi->num != 0);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int virtnet_probe(struct virtio_device *vdev)
|
||||
{
|
||||
int err;
|
||||
unsigned int len;
|
||||
struct net_device *dev;
|
||||
struct virtnet_info *vi;
|
||||
void *token;
|
||||
|
||||
/* Allocate ourselves a network device with room for our info */
|
||||
dev = alloc_etherdev(sizeof(struct virtnet_info));
|
||||
if (!dev)
|
||||
return -ENOMEM;
|
||||
|
||||
/* Set up network device as normal. */
|
||||
ether_setup(dev);
|
||||
dev->open = virtnet_open;
|
||||
dev->stop = virtnet_close;
|
||||
dev->hard_start_xmit = start_xmit;
|
||||
dev->features = NETIF_F_HIGHDMA;
|
||||
SET_NETDEV_DEV(dev, &vdev->dev);
|
||||
|
||||
/* Do we support "hardware" checksums? */
|
||||
token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_F, &len);
|
||||
if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_NO_CSUM)) {
|
||||
/* This opens up the world of extra features. */
|
||||
dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
|
||||
if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4))
|
||||
dev->features |= NETIF_F_TSO;
|
||||
if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_UFO))
|
||||
dev->features |= NETIF_F_UFO;
|
||||
if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4_ECN))
|
||||
dev->features |= NETIF_F_TSO_ECN;
|
||||
if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO6))
|
||||
dev->features |= NETIF_F_TSO6;
|
||||
}
|
||||
|
||||
/* Configuration may specify what MAC to use. Otherwise random. */
|
||||
token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_MAC_F, &len);
|
||||
if (token) {
|
||||
dev->addr_len = len;
|
||||
vdev->config->get(vdev, token, dev->dev_addr, len);
|
||||
} else
|
||||
random_ether_addr(dev->dev_addr);
|
||||
|
||||
/* Set up our device-specific information */
|
||||
vi = netdev_priv(dev);
|
||||
netif_napi_add(dev, &vi->napi, virtnet_poll, 16);
|
||||
vi->dev = dev;
|
||||
vi->vdev = vdev;
|
||||
|
||||
/* We expect two virtqueues, receive then send. */
|
||||
vi->rvq = vdev->config->find_vq(vdev, skb_recv_done);
|
||||
if (IS_ERR(vi->rvq)) {
|
||||
err = PTR_ERR(vi->rvq);
|
||||
goto free;
|
||||
}
|
||||
|
||||
vi->svq = vdev->config->find_vq(vdev, skb_xmit_done);
|
||||
if (IS_ERR(vi->svq)) {
|
||||
err = PTR_ERR(vi->svq);
|
||||
goto free_recv;
|
||||
}
|
||||
|
||||
/* Initialize our empty receive and send queues. */
|
||||
skb_queue_head_init(&vi->recv);
|
||||
skb_queue_head_init(&vi->send);
|
||||
|
||||
err = register_netdev(dev);
|
||||
if (err) {
|
||||
pr_debug("virtio_net: registering device failed\n");
|
||||
goto free_send;
|
||||
}
|
||||
pr_debug("virtnet: registered device %s\n", dev->name);
|
||||
vdev->priv = vi;
|
||||
return 0;
|
||||
|
||||
free_send:
|
||||
vdev->config->del_vq(vi->svq);
|
||||
free_recv:
|
||||
vdev->config->del_vq(vi->rvq);
|
||||
free:
|
||||
free_netdev(dev);
|
||||
return err;
|
||||
}
|
||||
|
||||
static void virtnet_remove(struct virtio_device *vdev)
|
||||
{
|
||||
unregister_netdev(vdev->priv);
|
||||
free_netdev(vdev->priv);
|
||||
}
|
||||
|
||||
static struct virtio_device_id id_table[] = {
|
||||
{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
|
||||
{ 0 },
|
||||
};
|
||||
|
||||
static struct virtio_driver virtio_net = {
|
||||
.driver.name = KBUILD_MODNAME,
|
||||
.driver.owner = THIS_MODULE,
|
||||
.id_table = id_table,
|
||||
.probe = virtnet_probe,
|
||||
.remove = __devexit_p(virtnet_remove),
|
||||
};
|
||||
|
||||
static int __init init(void)
|
||||
{
|
||||
return register_virtio_driver(&virtio_net);
|
||||
}
|
||||
|
||||
static void __exit fini(void)
|
||||
{
|
||||
unregister_virtio_driver(&virtio_net);
|
||||
}
|
||||
module_init(init);
|
||||
module_exit(fini);
|
||||
|
||||
MODULE_DEVICE_TABLE(virtio, id_table);
|
||||
MODULE_DESCRIPTION("Virtio network driver");
|
||||
MODULE_LICENSE("GPL");
|
||||
|
|
@ -344,6 +344,7 @@ unifdef-y += utsname.h
|
|||
unifdef-y += videodev2.h
|
||||
unifdef-y += videodev.h
|
||||
unifdef-y += virtio_config.h
|
||||
unifdef-y += virtio_net.h
|
||||
unifdef-y += wait.h
|
||||
unifdef-y += wanrouter.h
|
||||
unifdef-y += watchdog.h
|
||||
|
|
|
|||
|
|
@ -0,0 +1,36 @@
|
|||
#ifndef _LINUX_VIRTIO_NET_H
|
||||
#define _LINUX_VIRTIO_NET_H
|
||||
#include <linux/virtio_config.h>
|
||||
|
||||
/* The ID for virtio_net */
|
||||
#define VIRTIO_ID_NET 1
|
||||
|
||||
/* The bitmap of config for virtio net */
|
||||
#define VIRTIO_CONFIG_NET_F 0x40
|
||||
#define VIRTIO_NET_F_NO_CSUM 0
|
||||
#define VIRTIO_NET_F_TSO4 1
|
||||
#define VIRTIO_NET_F_UFO 2
|
||||
#define VIRTIO_NET_F_TSO4_ECN 3
|
||||
#define VIRTIO_NET_F_TSO6 4
|
||||
|
||||
/* The config defining mac address. */
|
||||
#define VIRTIO_CONFIG_NET_MAC_F 0x41
|
||||
|
||||
/* This is the first element of the scatter-gather list. If you don't
|
||||
* specify GSO or CSUM features, you can simply ignore the header. */
|
||||
struct virtio_net_hdr
|
||||
{
|
||||
#define VIRTIO_NET_HDR_F_NEEDS_CSUM 1 // Use csum_start, csum_offset
|
||||
__u8 flags;
|
||||
#define VIRTIO_NET_HDR_GSO_NONE 0 // Not a GSO frame
|
||||
#define VIRTIO_NET_HDR_GSO_TCPV4 1 // GSO frame, IPv4 TCP (TSO)
|
||||
/* FIXME: Do we need this? If they said they can handle ECN, do they care? */
|
||||
#define VIRTIO_NET_HDR_GSO_TCPV4_ECN 2 // GSO frame, IPv4 TCP w/ ECN
|
||||
#define VIRTIO_NET_HDR_GSO_UDP 3 // GSO frame, IPv4 UDP (UFO)
|
||||
#define VIRTIO_NET_HDR_GSO_TCPV6 4 // GSO frame, IPv6 TCP
|
||||
__u8 gso_type;
|
||||
__u16 gso_size;
|
||||
__u16 csum_start;
|
||||
__u16 csum_offset;
|
||||
};
|
||||
#endif /* _LINUX_VIRTIO_NET_H */
|
||||
Loading…
Reference in New Issue