[dpdk-dev] [PATCH] net/vdev_netvsc: print warning if Mellanox devices are not configured

[Ferruh Yigit]

On 5/23/2019 11:01 PM, Stephen Hemminger wrote:
> Several users have run into problems where the MLX drivers were not
> enabled in their build. And then trying to run their DPDK
> application on Azure. What happens is that all packets
> go over the slow path, and failsafe repeatedly probes for never
> existing sub-device.
> 
> Both Mellanox drivers should be checked. MLX4 for current versions,
> and MLX5 for future upgrades. This code is only called if Hyper-V/Azure
> is detected.
> 
> Signed-off-by: Stephen Hemminger <sthemmin at microsoft.com>
> ---
>  drivers/net/vdev_netvsc/vdev_netvsc.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/net/vdev_netvsc/vdev_netvsc.c b/drivers/net/vdev_netvsc/vdev_netvsc.c
> index 801f54c96e01..64f9dbf66e18 100644
> --- a/drivers/net/vdev_netvsc/vdev_netvsc.c
> +++ b/drivers/net/vdev_netvsc/vdev_netvsc.c
> @@ -812,6 +812,13 @@ vdev_netvsc_scan_callback(__rte_unused void *arg)
>  	struct rte_devargs *devargs;
>  	struct rte_bus *vbus = rte_bus_find_by_name("vdev");
>  
> +#ifndef RTE_LIBRTE_MLX4_PMD
> +	DRV_LOG(WARNING, "Mellanox MLX4 not configured.");
> +#endif
> +#ifndef RTE_LIBRTE_MLX5_PMD
> +	DRV_LOG(WARNING, "Mellanox MLX5 not configured.");
> +#endif

Is it OK a virtual PMD being this much aware of another PMD?
Can it be an option to add this check into build system? And if there is direct
dependency perhaps even don't compile the 'vdev_netvsc' when none mlx PMD is
enabled.

> +
>  	RTE_EAL_DEVARGS_FOREACH("vdev", devargs)
>  		if (!strncmp(devargs->name, VDEV_NETVSC_DRIVER_NAME,
>  			     VDEV_NETVSC_DRIVER_NAME_LEN))
>