[Xen-devel] [PATCH net-next 4/8] xen-netback: accept an L4 or L3 skb hash value from the frontend

[Paul Durrant <paul.durrant@xxxxxxxxxx>]

This patch adds an indication that netback is capable of handling hash
values passed from the frontend (see netif.h for details), and the code
necessary to process the additional xen_netif_extra_info segment and
set a hash on the skb.

Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 drivers/net/xen-netback/netback.c | 25 +++++++++++++++++++++++++
 drivers/net/xen-netback/xenbus.c  |  8 ++++++++
 2 files changed, 33 insertions(+)

diff --git a/drivers/net/xen-netback/netback.c 
b/drivers/net/xen-netback/netback.c
index 9f0c9f5..3799b5a 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1383,6 +1383,28 @@ static void xenvif_tx_build_gops(struct xenvif_queue 
*queue,
                        }
                }
 
+               if (extras[XEN_NETIF_EXTRA_TYPE_HASH - 1].type) {
+                       struct xen_netif_extra_info *extra;
+                       u32 hash = *(u32 *)extra->u.hash.value;
+
+                       extra = &extras[XEN_NETIF_EXTRA_TYPE_HASH - 1];
+
+                       switch (extra->u.hash.type) {
+                       case XEN_NETIF_HASH_TYPE_TCPV4:
+                       case XEN_NETIF_HASH_TYPE_TCPV6:
+                               skb_set_hash(skb, hash, PKT_HASH_TYPE_L4);
+                               break;
+
+                       case XEN_NETIF_HASH_TYPE_IPV4:
+                       case XEN_NETIF_HASH_TYPE_IPV6:
+                               skb_set_hash(skb, hash, PKT_HASH_TYPE_L3);
+                               break;
+
+                       default:
+                               break;
+                       }
+               }
+
                XENVIF_TX_CB(skb)->pending_idx = pending_idx;
 
                __skb_put(skb, data_len);
@@ -1416,6 +1438,9 @@ static void xenvif_tx_build_gops(struct xenvif_queue 
*queue,
                if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type)
                        queue->pending_tx_info[pending_idx].extra_count++;
 
+               if (extras[XEN_NETIF_EXTRA_TYPE_HASH - 1].type)
+                       queue->pending_tx_info[pending_idx].extra_count++;
+
                queue->pending_cons++;
 
                gop = xenvif_get_requests(queue, skb, txfrags, gop,
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 929a6e7..2fa8a16 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -335,6 +335,14 @@ static int netback_probe(struct xenbus_device *dev,
                        goto abort_transaction;
                }
 
+               /* We support hash values. */
+               err = xenbus_printf(xbt, dev->nodename,
+                                   "feature-hash", "%d", 1);
+               if (err) {
+                       message = "writing feature-hash";
+                       goto abort_transaction;
+               }
+
                err = xenbus_transaction_end(xbt, 0);
        } while (err == -EAGAIN);
 
-- 
2.1.4


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