IB/mlx5: Report mlx5 TSO capabilities when querying device

Enable mlx5 based hardware to report TCP segmentation offload (TSO)
capabilities from kernel to user space. A TSO enabled NIC will accept
big chunks of data with sizes greater than MTU for TCP traffic.  The TSO
engine will break the data into separate packets and will insert headers
automatically.

The capabilities are exposed to user space through query_device by uhw
directly. The following capabilities are reported:

1. The maximum payload size in bytes supported for segmentation by TSO
   engine.
2. Bitmap showing which QP types are supported by TSO operation. The bitmap
   is built by members from 'enmu ib_qp_type'. For example, similar code
   should be performed if UD QP is supported:
	supported_qpts |= 1 << IB_QPT_UD;

To make user-space library aware of whether kernel supports uhw or not, a
new flag: cmds_supp_uhw will be returned back to user-space through
alloc_ucontext.

Signed-off-by: Bodong Wang <bodong@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 36 insertions, 5 deletions

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index 8f832fc20341..a7cc6d74d3b0 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -459,8 +459,17 @@ static int mlx5_ib_query_device(struct ib_device *ibdev,
 	int max_rq_sg;
 	int max_sq_sg;
 	u64 min_page_size = 1ull << MLX5_CAP_GEN(mdev, log_pg_sz);
+	struct mlx5_ib_query_device_resp resp = {};
+	size_t resp_len;
+	u64 max_tso;
 
-	if (uhw->inlen || uhw->outlen)
+	resp_len = sizeof(resp.comp_mask) + sizeof(resp.response_length);
+	if (uhw->outlen && uhw->outlen < resp_len)
+		return -EINVAL;
+	else
+		resp.response_length = resp_len;
+
+	if (uhw->inlen && !ib_is_udata_cleared(uhw, 0, uhw->inlen))
 		return -EINVAL;
 
 	memset(props, 0, sizeof(*props));
@@ -513,10 +522,21 @@ static int mlx5_ib_query_device(struct ib_device *ibdev,
 	if (MLX5_CAP_GEN(mdev, block_lb_mc))
 		props->device_cap_flags |= IB_DEVICE_BLOCK_MULTICAST_LOOPBACK;
 
-	if (MLX5_CAP_GEN(dev->mdev, eth_net_offloads) &&
-	    (MLX5_CAP_ETH(dev->mdev, csum_cap)))
+	if (MLX5_CAP_GEN(dev->mdev, eth_net_offloads)) {
+		if (MLX5_CAP_ETH(mdev, csum_cap))
 			props->device_cap_flags |= IB_DEVICE_RAW_IP_CSUM;
 
+		if (field_avail(typeof(resp), tso_caps, uhw->outlen)) {
+			max_tso = MLX5_CAP_ETH(mdev, max_lso_cap);
+			if (max_tso) {
+				resp.tso_caps.max_tso = 1 << max_tso;
+				resp.tso_caps.supported_qpts |=
+					1 << IB_QPT_RAW_PACKET;
+				resp.response_length += sizeof(resp.tso_caps);
+			}
+		}
+	}
+
 	if (MLX5_CAP_GEN(mdev, ipoib_basic_offloads)) {
 		props->device_cap_flags |= IB_DEVICE_UD_IP_CSUM;
 		props->device_cap_flags |= IB_DEVICE_UD_TSO;
@@ -578,6 +598,13 @@ static int mlx5_ib_query_device(struct ib_device *ibdev,
 	if (!mlx5_core_is_pf(mdev))
 		props->device_cap_flags |= IB_DEVICE_VIRTUAL_FUNCTION;
 
+	if (uhw->outlen) {
+		err = ib_copy_to_udata(uhw, &resp, resp.response_length);
+
+		if (err)
+			return err;
+	}
+
 	return 0;
 }
 
@@ -995,6 +1022,11 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev,
 	if (field_avail(typeof(resp), cqe_version, udata->outlen))
 		resp.response_length += sizeof(resp.cqe_version);
 
+	if (field_avail(typeof(resp), cmds_supp_uhw, udata->outlen)) {
+		resp.cmds_supp_uhw |= MLX5_USER_CMDS_SUPP_UHW_QUERY_DEVICE;
+		resp.response_length += sizeof(resp.cmds_supp_uhw);
+	}
+
 	/*
 	 * 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
@@ -1009,8 +1041,7 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev,
 			offsetof(struct mlx5_init_seg, internal_timer_h) %
 			PAGE_SIZE;
 		resp.response_length += sizeof(resp.hca_core_clock_offset) +
-					sizeof(resp.reserved2) +
-					sizeof(resp.reserved3);
+					sizeof(resp.reserved2);
 	}
 
 	err = ib_copy_to_udata(udata, &resp, resp.response_length);