net/mlx4_core: Disable mlx4_QP_ATTACH calls from guests if the host uses flow steering

Guests kernels may not correctly detect if DMFS (device-enabled flow steering) is
activated by the host. If DMFS is activated, the master should return error to guests
which try to use the B0-steering flow calls (mlx4_QP_ATTACH).
Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/resource_tracker.c

@@ -2990,6 +2990,9 @@ int mlx4_QP_ATTACH_wrapper(struct mlx4_dev *dev, int slave,
 	u8 steer_type_mask = 2;
 	enum mlx4_steer_type type = (gid[7] & steer_type_mask) >> 1;
 
+	if (dev->caps.steering_mode != MLX4_STEERING_MODE_B0)
+		return -EINVAL;
+
 	qpn = vhcr->in_modifier & 0xffffff;
 	err = get_res(dev, slave, qpn, RES_QP, &rqp);
 	if (err)