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: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 3492ae0..73f01db 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -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. */

diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
index 1456f7b..1ea3351 100644 (file)
--- a/include/linux/virtio_net.h
+++ b/include/linux/virtio_net.h
@@ -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 */