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Commit 34a48579 authored by Rusty Russell's avatar Rusty Russell
Browse files

virtio: Tweak virtio_net defines 



1) Turn GSO on virtio net into an all-or-nothing (keep checksumming
   separate).  Having multiple bits is a pain: if you can't support something
   you should handle it in software, which is still a performance win.

2) Make VIRTIO_NET_HDR_GSO_ECN a flag in the header, so it can apply to
   IPv6 or v4.

3) Rename VIRTIO_NET_F_NO_CSUM to VIRTIO_NET_F_CSUM (ie. means we do
   checksumming).

4) Add csum and gso params to virtio_net to allow more testing.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 50c8ea80

drivers/net/virtio_net.c

+16 −16
Original line number Diff line number Diff line
@@ -24,6 +24,10 @@ 
#include <linux/virtio_net.h>

#include <linux/scatterlist.h>



static int csum = 1, gso = 1;

module_param(csum, bool, 0444);

module_param(gso, bool, 0444);



/* FIXME: MTU in config. */

#define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN)
@@ -88,13 +92,10 @@ static void receive_skb(struct net_device *dev, struct sk_buff *skb, 


	if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {

		pr_debug("GSO!\n");

		switch (hdr->gso_type) {

		switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {

		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;
@@ -108,6 +109,9 @@ static void receive_skb(struct net_device *dev, struct sk_buff *skb, 
			goto frame_err;

		}



		if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)

			skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;



		skb_shinfo(skb)->gso_size = hdr->gso_size;

		if (skb_shinfo(skb)->gso_size == 0) {

			if (net_ratelimit())
@@ -244,9 +248,7 @@ static int start_xmit(struct sk_buff *skb, struct net_device *dev) 
	if (skb_is_gso(skb)) {

		hdr->hdr_len = skb_transport_header(skb) - skb->data;

		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)

		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;
@@ -254,6 +256,8 @@ static int start_xmit(struct sk_buff *skb, struct net_device *dev) 
			hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;

		else

			BUG();

		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)

			hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;

	} else {

		hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;

		hdr->gso_size = hdr->hdr_len = 0;
@@ -330,17 +334,13 @@ static int virtnet_probe(struct virtio_device *vdev) 
	SET_NETDEV_DEV(dev, &vdev->dev);



	/* Do we support "hardware" checksums? */

	if (vdev->config->feature(vdev, VIRTIO_NET_F_NO_CSUM)) {

	if (csum && vdev->config->feature(vdev, VIRTIO_NET_F_CSUM)) {

		/* This opens up the world of extra features. */

		dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;

		if (vdev->config->feature(vdev, VIRTIO_NET_F_TSO4))

			dev->features |= NETIF_F_TSO;

		if (vdev->config->feature(vdev, VIRTIO_NET_F_UFO))

			dev->features |= NETIF_F_UFO;

		if (vdev->config->feature(vdev, VIRTIO_NET_F_TSO4_ECN))

			dev->features |= NETIF_F_TSO_ECN;

		if (vdev->config->feature(vdev, VIRTIO_NET_F_TSO6))

			dev->features |= NETIF_F_TSO6;

		if (gso && vdev->config->feature(vdev, VIRTIO_NET_F_GSO)) {

			dev->features |= NETIF_F_TSO | NETIF_F_UFO

				| NETIF_F_TSO_ECN | NETIF_F_TSO6;

		}

	}



	/* Configuration may specify what MAC to use.  Otherwise random. */

include/linux/virtio_net.h

+4 −8
Original line number Diff line number Diff line
@@ -6,12 +6,9 @@ 
#define VIRTIO_ID_NET	1



/* The feature bitmap for virtio net */

#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

#define VIRTIO_NET_F_MAC	5

#define VIRTIO_NET_F_CSUM	0	/* Can handle pkts w/ partial csum */

#define VIRTIO_NET_F_MAC	5	/* Host has given MAC address. */

#define VIRTIO_NET_F_GSO	6	/* Can handle pkts w/ any GSO type */



struct virtio_net_config

{
@@ -27,10 +24,9 @@ struct virtio_net_hdr 
	__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

#define VIRTIO_NET_HDR_GSO_ECN		0x80	// TCP has ECN set

	__u8 gso_type;

	__u16 hdr_len;		/* Ethernet + IP + tcp/udp hdrs */

	__u16 gso_size;		/* Bytes to append to gso_hdr_len per frame */