xen-netback: add support for IPv6 checksum offload to guest

Check xenstore flag feature-ipv6-csum-offload to determine if a
guest is happy to accept IPv6 packets with only partial checksum.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 15 insertions, 5 deletions

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 5715318d6bab..b4a9a3c844b2 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -153,7 +153,8 @@ struct xenvif {
         u8 can_sg:1;
         u8 gso:1;
         u8 gso_prefix:1;
-        u8 csum:1;
+        u8 ip_csum:1;
+        u8 ipv6_csum:1;
 
         /* Internal feature information. */
         u8 can_queue:1;     /* can queue packets for receiver? */
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 01bb854c7f62..8e927838652c 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -216,8 +216,10 @@ static netdev_features_t xenvif_fix_features(struct net_device *dev,
                 features &= ~NETIF_F_SG;
         if (!vif->gso && !vif->gso_prefix)
                 features &= ~NETIF_F_TSO;
-        if (!vif->csum)
+        if (!vif->ip_csum)
                 features &= ~NETIF_F_IP_CSUM;
+        if (!vif->ipv6_csum)
+                features &= ~NETIF_F_IPV6_CSUM;
 
         return features;
 }
@@ -306,7 +308,7 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
         vif->domid  = domid;
         vif->handle = handle;
         vif->can_sg = 1;
-        vif->csum = 1;
+        vif->ip_csum = 1;
         vif->dev = dev;
 
         vif->credit_bytes = vif->remaining_credit = ~0UL;
@@ -316,7 +318,9 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
         vif->credit_timeout.expires = jiffies;
 
         dev->netdev_ops = &xenvif_netdev_ops;
-        dev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO;
+        dev->hw_features = NETIF_F_SG |
+                NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
+                NETIF_F_TSO;
         dev->features = dev->hw_features;
         SET_ETHTOOL_OPS(dev, &xenvif_ethtool_ops);
 
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 1b08d8798372..ad27b15242cd 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -574,7 +574,12 @@ static int connect_rings(struct backend_info *be)
         if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload",
                          "%d", &val) < 0)
                 val = 0;
-        vif->csum = !val;
+        vif->ip_csum = !val;
+
+        if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-ipv6-csum-offload",
+                         "%d", &val) < 0)
+                val = 0;
+        vif->ipv6_csum = !!val;
 
         /* Map the shared frame, irq etc. */
         err = xenvif_connect(vif, tx_ring_ref, rx_ring_ref,