[PATCH 04/15] net/enic: allow flow mark ID 0

[Hyong Youb Kim <hyonkim@cisco.com>]

The driver currently accepts mark ID 0 but does not report it in
matching packet's mbuf. For example, the following testpmd command
succeeds. But, the mbuf of a matching IPv4 UDP packet does not have
PKT_RX_FDIR_ID set.

flow create 0 ingress pattern ... actions mark id 0 / queue index 0 / end

The problem has to do with mapping mark IDs (32-bit) to NIC filter
IDs. Filter ID is currently 16-bit, so values greater than 0xffff are
rejected. The firmware reserves filter ID 0 for filters that do not
mark (e.g. steer w/o mark). And, the driver reserves 0xffff for the
flag action. This leaves 1...0xfffe for app use.

It is possible to simply reject mark ID 0 as unsupported. But, 0 is
commonly used (e.g. OVS-DPDK and VPP). So, when adding a filter, set
filter ID = mark ID + 1 to support mark ID 0. The receive handler
subtracts 1 from filter ID to get back the original mark ID.

Fixes: dfbd6a9cb504 ("net/enic: extend flow director support for 1300 series")
Cc: stable@dpdk.org

Signed-off-by: Hyong Youb Kim <hyonkim@cisco.com>
Reviewed-by: John Daley <johndale@cisco.com>
---
 drivers/net/enic/enic_flow.c        | 15 +++++++++++----
 drivers/net/enic/enic_rxtx_common.h |  3 ++-
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/net/enic/enic_flow.c b/drivers/net/enic/enic_flow.c
index 55d8d50a1..e12a6ec73 100644
--- a/drivers/net/enic/enic_flow.c
+++ b/drivers/net/enic/enic_flow.c
@@ -1081,12 +1081,18 @@ enic_copy_action_v2(const struct rte_flow_action actions[],
 			if (overlap & MARK)
 				return ENOTSUP;
 			overlap |= MARK;
-			/* ENIC_MAGIC_FILTER_ID is reserved and is the highest
-			 * in the range of allows mark ids.
+			/*
+			 * Map mark ID (32-bit) to filter ID (16-bit):
+			 * - Reject values > 16 bits
+			 * - Filter ID 0 is reserved for filters that steer
+			 *   but not mark. So add 1 to the mark ID to avoid
+			 *   using 0.
+			 * - Filter ID (ENIC_MAGIC_FILTER_ID = 0xffff) is
+			 *   reserved for the "flag" action below.
 			 */
-			if (mark->id >= ENIC_MAGIC_FILTER_ID)
+			if (mark->id >= ENIC_MAGIC_FILTER_ID - 1)
 				return EINVAL;
-			enic_action->filter_id = mark->id;
+			enic_action->filter_id = mark->id + 1;
 			enic_action->flags |= FILTER_ACTION_FILTER_ID_FLAG;
 			break;
 		}
@@ -1094,6 +1100,7 @@ enic_copy_action_v2(const struct rte_flow_action actions[],
 			if (overlap & MARK)
 				return ENOTSUP;
 			overlap |= MARK;
+			/* ENIC_MAGIC_FILTER_ID is reserved for flagging */
 			enic_action->filter_id = ENIC_MAGIC_FILTER_ID;
 			enic_action->flags |= FILTER_ACTION_FILTER_ID_FLAG;
 			break;
diff --git a/drivers/net/enic/enic_rxtx_common.h b/drivers/net/enic/enic_rxtx_common.h
index bfbb4909e..66f631dfe 100644
--- a/drivers/net/enic/enic_rxtx_common.h
+++ b/drivers/net/enic/enic_rxtx_common.h
@@ -226,7 +226,8 @@ enic_cq_rx_to_pkt_flags(struct cq_desc *cqd, struct rte_mbuf *mbuf)
 		if (filter_id) {
 			pkt_flags |= PKT_RX_FDIR;
 			if (filter_id != ENIC_MAGIC_FILTER_ID) {
-				mbuf->hash.fdir.hi = clsf_cqd->filter_id;
+				/* filter_id = mark id + 1, so subtract 1 */
+				mbuf->hash.fdir.hi = filter_id - 1;
 				pkt_flags |= PKT_RX_FDIR_ID;
 			}
 		}
-- 
2.16.2