[PATCH 1/2] net/mlx4: fix Rx after updating number of queues

[PATCH 1/2] net/mlx4: fix Rx after updating number of queues

[Adrien Mazarguil]

When not in isolated mode, internal flow rules are automatically maintained
by the PMD to receive traffic according to global device settings (MAC,
VLAN, promiscuous mode and so on).

Since RSS support was added to the mix, it must also check whether Rx queue
configuration has changed when refreshing flow rules to prevent the
following from happening:

- With a smaller number of Rx queues, traffic is implicitly dropped since
  the existing RSS context cannot be re-applied.
- With a larger number of Rx queues, traffic remains balanced within the
  original (smaller) set of queues.

One workaround before this commit was to temporarily enter/leave isolated
mode to make it regenerate internal flow rules.

Fixes: 7d8675956f57 ("net/mlx4: add RSS support outside flow API")

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
---
 drivers/net/mlx4/mlx4_flow.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/net/mlx4/mlx4_flow.c b/drivers/net/mlx4/mlx4_flow.c
index 7a6097f..86bac1b 100644
--- a/drivers/net/mlx4/mlx4_flow.c
+++ b/drivers/net/mlx4/mlx4_flow.c
@@ -1342,6 +1342,7 @@ mlx4_flow_internal(struct priv *priv, struct rte_flow_error *error)
 			assert(flow->ibv_attr->type == IBV_FLOW_ATTR_NORMAL);
 			assert(flow->ibv_attr->num_of_specs == 1);
 			assert(eth->type == IBV_FLOW_SPEC_ETH);
+			assert(flow->rss);
 			if (rule_vlan &&
 			    (eth->val.vlan_tag != *rule_vlan ||
 			     eth->mask.vlan_tag != RTE_BE16(0x0fff)))
@@ -1354,8 +1355,13 @@ mlx4_flow_internal(struct priv *priv, struct rte_flow_error *error)
 				    eth->val.src_mac[j] != UINT8_C(0x00) ||
 				    eth->mask.src_mac[j] != UINT8_C(0x00))
 					break;
-			if (j == sizeof(mac->addr_bytes))
-				break;
+			if (j != sizeof(mac->addr_bytes))
+				continue;
+			if (flow->rss->queues != queues ||
+			    memcmp(flow->rss->queue_id, rss_conf->queue,
+				   queues * sizeof(flow->rss->queue_id[0])))
+				continue;
+			break;
 		}
 		if (!flow || !flow->internal) {
 			/* Not found, create a new flow rule. */
@@ -1389,6 +1395,13 @@ mlx4_flow_internal(struct priv *priv, struct rte_flow_error *error)
 					break;
 			}
 		}
+		if (flow && flow->internal) {
+			assert(flow->rss);
+			if (flow->rss->queues != queues ||
+			    memcmp(flow->rss->queue_id, rss_conf->queue,
+				   queues * sizeof(flow->rss->queue_id[0])))
+				flow = NULL;
+		}
 		if (!flow || !flow->internal) {
 			/* Not found, create a new flow rule. */
 			if (priv->dev->data->promiscuous) {
-- 
2.1.4

[PATCH 2/2] net/mlx4: fix queue index check on flow rules

[Adrien Mazarguil]

Users are not prevented from creating flow rules targeting nonexistent
queues, which silently makes such rules drop-like.

While it can be thought as a feature, reporting an error instead is
actually far more useful in order to catch common mistakes.

Fixes: 078b8b452e6b ("net/mlx4: add RSS flow rule action support")

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
---
 drivers/net/mlx4/mlx4_flow.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/net/mlx4/mlx4_flow.c b/drivers/net/mlx4/mlx4_flow.c
index 86bac1b..8b87b29 100644
--- a/drivers/net/mlx4/mlx4_flow.c
+++ b/drivers/net/mlx4/mlx4_flow.c
@@ -734,6 +734,11 @@ mlx4_flow_prepare(struct priv *priv,
 			if (flow->rss)
 				break;
 			queue = action->conf;
+			if (queue->index >= priv->dev->data->nb_rx_queues) {
+				msg = "queue target index beyond number of"
+					" configured Rx queues";
+				goto exit_action_not_supported;
+			}
 			flow->rss = mlx4_rss_get
 				(priv, 0, mlx4_rss_hash_key_default, 1,
 				 &queue->index);
@@ -760,6 +765,15 @@ mlx4_flow_prepare(struct priv *priv,
 						   ETH_RSS_NONFRAG_IPV6_TCP),
 				};
 			/* Sanity checks. */
+			for (i = 0; i < rss->num; ++i)
+				if (rss->queue[i] >=
+				    priv->dev->data->nb_rx_queues)
+					break;
+			if (i != rss->num) {
+				msg = "queue index target beyond number of"
+					" configured Rx queues";
+				goto exit_action_not_supported;
+			}
 			if (!rte_is_power_of_2(rss->num)) {
 				msg = "for RSS, mlx4 requires the number of"
 					" queues to be a power of two";
-- 
2.1.4