[net-next 06/14] net/mlx5: E-switch, Add checking for flow rule destinations

[Saeed Mahameed <saeed@kernel.org>]

From: Jianbo Liu <jianbol@nvidia.com>

Firmware doesn't allow flow rules in FDB to do header rewrite and send
packets to both internal and uplink vports. The following syndrome
will be generated when trying to offload such kind of rules:

mlx5_core 0000:08:00.0: mlx5_cmd_out_err:803:(pid 23569): SET_FLOW_TABLE_ENTRY(0x936) op_mod(0x0) failed, status bad parameter(0x3), syndrome (0x8c8f08), err(-22)

To avoid this syndrome, add a checking before creating FTE. If a rule
with header rewrite action forwards packets to both VF and PF, an
error is returned directly.

Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
---
 .../mellanox/mlx5/core/eswitch_offloads.c     | 31 +++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
index e391535e1ab1..46b8c60ac39a 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
@@ -535,6 +535,28 @@ esw_src_port_rewrite_supported(struct mlx5_eswitch *esw)
 	       MLX5_CAP_ESW_FLOWTABLE_FDB(esw->dev, ignore_flow_level);
 }
 
+static bool
+esw_dests_to_vf_pf_vports(struct mlx5_flow_destination *dests, int max_dest)
+{
+	bool vf_dest = false, pf_dest = false;
+	int i;
+
+	for (i = 0; i < max_dest; i++) {
+		if (dests[i].type != MLX5_FLOW_DESTINATION_TYPE_VPORT)
+			continue;
+
+		if (dests[i].vport.num == MLX5_VPORT_UPLINK)
+			pf_dest = true;
+		else
+			vf_dest = true;
+
+		if (vf_dest && pf_dest)
+			return true;
+	}
+
+	return false;
+}
+
 static int
 esw_setup_dests(struct mlx5_flow_destination *dest,
 		struct mlx5_flow_act *flow_act,
@@ -671,6 +693,15 @@ mlx5_eswitch_add_offloaded_rule(struct mlx5_eswitch *esw,
 			rule = ERR_PTR(err);
 			goto err_create_goto_table;
 		}
+
+		/* Header rewrite with combined wire+loopback in FDB is not allowed */
+		if ((flow_act.action & MLX5_FLOW_CONTEXT_ACTION_MOD_HDR) &&
+		    esw_dests_to_vf_pf_vports(dest, i)) {
+			esw_warn(esw->dev,
+				 "FDB: Header rewrite with forwarding to both PF and VF is not allowed\n");
+			rule = ERR_PTR(-EINVAL);
+			goto err_esw_get;
+		}
 	}
 
 	if (esw_attr->decap_pkt_reformat)
-- 
2.41.0