[PATCH 03/18] IB/mlx5: Enable Eth VFs to query their min-inline value for user-space

[Talat Batheesh]

From: Or Gerlitz <ogerlitz at mellanox.com>

BugLink: https://bugs.launchpad.net/ubuntu/1668019

For some mlx5 HW models (CX4, CX4Lx), the VF driver needs to put part
of the packet headers on the TX descriptor so the e-switch can do proper
matching and steering. This is called "min-inline", it's advertized to
the VF by the FW and also enforced on them by the HW, such that if they
don't obey, their packets are dropped.

SRIOV VF libmlx5 instances should take into account the min-inline
value of their vports. For that end, we provide this value through
the vendor response part of init_ucontext command.

The min inline value is reported in a way which will let newer libmlx5
instances realize that they are running over an older kernel and act
accordingly (e.g apply some educated guess).

Signed-off-by: Or Gerlitz <ogerlitz at mellanox.com>
Reviewed-by: Matan Barak <matanb at mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm at mellanox.com>
(cherry picked from commit 7898489880f55a9c3a954cd5660a0fb4fd81b625)
Signed-off-by: Talat Batheesh <talatb at mellanox.com>
---
 drivers/infiniband/hw/mlx5/main.c |  9 +++++++++
 include/uapi/rdma/mlx5-abi.h      | 14 +++++++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index d566f67..1cce06f 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -53,6 +53,7 @@
 #include <linux/in.h>
 #include <linux/etherdevice.h>
 #include <linux/mlx5/fs.h>
+#include <linux/mlx5/vport.h>
 #include "mlx5_ib.h"
 
 #define DRIVER_NAME "mlx5_ib"
@@ -1135,6 +1136,14 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev,
 		resp.response_length += sizeof(resp.cmds_supp_uhw);
 	}
 
+	if (field_avail(typeof(resp), eth_min_inline, udata->outlen)) {
+		if (mlx5_ib_port_link_layer(ibdev, 1) == IB_LINK_LAYER_ETHERNET) {
+			mlx5_query_min_inline(dev->mdev, &resp.eth_min_inline);
+			resp.eth_min_inline++;
+		}
+		resp.response_length += sizeof(resp.eth_min_inline);
+	}
+
 	/*
 	 * We don't want to expose information from the PCI bar that is located
 	 * after 4096 bytes, so if the arch only supports larger pages, let's
diff --git a/include/uapi/rdma/mlx5-abi.h b/include/uapi/rdma/mlx5-abi.h
index fae6cda..844d288 100644
--- a/include/uapi/rdma/mlx5-abi.h
+++ b/include/uapi/rdma/mlx5-abi.h
@@ -85,6 +85,17 @@ enum mlx5_user_cmds_supp_uhw {
 	MLX5_USER_CMDS_SUPP_UHW_CREATE_AH    = 1 << 1,
 };
 
+/* The eth_min_inline response value is set to off-by-one vs the FW
+ * returned value to allow user-space to deal with older kernels.
+ */
+enum mlx5_user_inline_mode {
+	MLX5_USER_INLINE_MODE_NA,
+	MLX5_USER_INLINE_MODE_NONE,
+	MLX5_USER_INLINE_MODE_L2,
+	MLX5_USER_INLINE_MODE_IP,
+	MLX5_USER_INLINE_MODE_TCP_UDP,
+};
+
 struct mlx5_ib_alloc_ucontext_resp {
 	__u32	qp_tab_size;
 	__u32	bf_reg_size;
@@ -101,7 +112,8 @@ struct mlx5_ib_alloc_ucontext_resp {
 	__u32	response_length;
 	__u8	cqe_version;
 	__u8	cmds_supp_uhw;
-	__u16	reserved2;
+	__u8	eth_min_inline;
+	__u8	reserved2;
 	__u64	hca_core_clock_offset;
 };
 
-- 
2.5.0