[ovs-dev] [PATCH] netdev-dpdk: add sflow support for vhost-user ports

[Kavanagh, Mark B]

Hi Przemek,

A few review comments inline.

Also, the patch/commit name suggests that sFlow support is only added for vhost-user ports, but it's also added for dpdk_eth ports, right?

Cheers,
Mark

>
>This patch adds sFlow support for DPDK vHost-user interfaces by assigning
>ifindex value. Values of ifindexes for vHost-user interfaces start with 2000
>to avoid overlapping with kernel datapath interfaces.
>
>Patch also fixes issue with 'dpdk0' interface being ignored by sFlow agent,
>because of ifindex 0. Ifindexes values for physical DPDK interfaces start
>with 1000 to avoid overlapping with kernel datapath interfaces.
>
>Signed-off-by: Przemyslaw Lal <przemyslawx.lal at intel.com>
>---
> lib/netdev-dpdk.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 58 insertions(+), 1 deletion(-)
>
>diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
>index 208c5f5..707e1d2 100644
>--- a/lib/netdev-dpdk.c
>+++ b/lib/netdev-dpdk.c
>@@ -115,6 +115,16 @@ static char *vhost_sock_dir = NULL;   /* Location of vhost-user sockets
>*/
>  */
> #define VHOST_ENQ_RETRY_USECS 100
>
>+/* For DPDK ETH interfaces use ifindex values starting with 1000
>+ * to avoid overlapping with kernel-space interfaces.
>+ * Also starting with 0 would cause sFlow to ignore 'dpdk0' interface.
>+ */
>+#define DPDK_PORT_ID_TO_IFINDEX(port_id) ((port_id) + 1000)
>+
>+/* For DPDK vhost-user interfaces use ifindexes starting with 2000.
>+ */
>+#define VHOST_ID_TO_IFINDEX(port_id) ((port_id) + 2000)
>+
> static const struct rte_eth_conf port_conf = {
>     .rxmode = {
>         .mq_mode = ETH_MQ_RX_RSS,
>@@ -149,6 +159,7 @@ enum dpdk_dev_type {
> static int rte_eal_init_ret = ENODEV;
>
> static struct ovs_mutex dpdk_mutex = OVS_MUTEX_INITIALIZER;
>+static struct ovs_mutex vhost_mutex = OVS_MUTEX_INITIALIZER;
>
> /* Quality of Service */
>
>@@ -790,6 +801,45 @@ netdev_dpdk_vhost_cuse_construct(struct netdev *netdev)
>     return err;
> }
>
>+/* Counter for VHOST interfaces as DPDK library doesn't provide mechanism
>+ * similar to rte_eth_dev_count for vhost-user sockets.
>+ */
>+static int vhost_counter OVS_GUARDED_BY(vhost_mutex) = 0;
>+
>+/* Array storing vhost_ids, so their ifindex can be reused after socket
>+ * recreation.
>+ */
>+static char vhost_ids[1024][PATH_MAX] OVS_GUARDED_BY(vhost_mutex);

Consider using a macro for the length of 'vhost_ids', e.g. VHOST_IDS_MAX_LEN - see a later comment on how this could be used.

>+
>+/* Simple lookup in vhost_ids array.
>+ * On success returns id of vhost_id stored in the array,
>+ * otherwise returns -1.
>+ */
>+static int
>+netdev_dpdk_lookup_vhost_id(struct netdev_dpdk *dev) OVS_REQUIRES(vhost_mutex)
>+{
>+    for (int i = 0; i <= vhost_counter; i++) {
>+        if (strncmp(vhost_ids[i], dev->vhost_id, strlen(dev->vhost_id)) == 0) {
>+            return i;
>+        }
>+    }
>+    return -1;
>+}
>+
>+/* Inserts vhost_id at the first free position in the vhost_ids array.
>+ */
>+static void
>+netdev_dpdk_push_vhost_id(struct netdev_dpdk *dev)
>+{
>+    ovs_mutex_lock(&vhost_mutex);
>+    if (netdev_dpdk_lookup_vhost_id(dev) < 0) {

You should perform a bounds check on 'vhost_counter' to ensure that it doesn't stray past the end of 'vhost_ids'.
e.g. if vhost_counter < VHOST_IDS_MAX_LEN, then perform the strncpy, otherwise warn the user that the list is full.

>+        strncpy(vhost_ids[vhost_counter++], dev->vhost_id,
>+                strlen(dev->vhost_id));
>+    }
>+    ovs_mutex_unlock(&vhost_mutex);
>+}
>+
>+

Remove the extraneous blank line, above.

> static int
> netdev_dpdk_vhost_user_construct(struct netdev *netdev)
> {
>@@ -825,6 +875,8 @@ netdev_dpdk_vhost_user_construct(struct netdev *netdev)
>         err = vhost_construct_helper(netdev);
>     }
>
>+    netdev_dpdk_push_vhost_id(dev);
>+
>     ovs_mutex_unlock(&dpdk_mutex);
>     return err;
> }
>@@ -1775,7 +1827,12 @@ netdev_dpdk_get_ifindex(const struct netdev *netdev)
>     int ifindex;
>
>     ovs_mutex_lock(&dev->mutex);
>-    ifindex = dev->port_id;
>+    if (dev->type == DPDK_DEV_ETH) {
>+        ifindex = DPDK_PORT_ID_TO_IFINDEX(dev->port_id);
>+    }
>+    else {
>+        ifindex = VHOST_ID_TO_IFINDEX(netdev_dpdk_lookup_vhost_id(dev));
>+    }
>     ovs_mutex_unlock(&dev->mutex);
>
>     return ifindex;
>--
>2.1.0
>
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