Re: [dpdk-dev] [PATCH] ethdev: limit maximum number of queues

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 11/27/2019 1:42 PM, Thomas Monjalon wrote:
> A buffer overflow happens in testpmd with some drivers
> since the queue arrays are limited to RTE_MAX_QUEUES_PER_PORT.
> 
> The advertised capabilities of mlx4, mlx5 and softnic
> for the number of queues were the maximum number: UINT16_MAX.
> They must be limited by the configured RTE_MAX_QUEUES_PER_PORT
> that applications expect to be respected.
> 
> The limitation is applied in above drivers having no limitation,
> and at ethdev level (function rte_eth_dev_info_get), in order
> to force the configured limit for all drivers.

The limit is not device limit, should we reflect it into PMDs?
Why not keep the limit only in the ethdev?

> 
> Fixes: 7fae69eeff13 ("mlx4: new poll mode driver")
> Fixes: e60fbd5b24fc ("mlx5: add device configure/start/stop")
> Fixes: cc6d421574fe ("net/softnic: add softnic PMD")
> Fixes: 9e6b36c34ce9 ("app/testpmd: reduce memory consumption")
> Cc: stable@dpdk.org
> 
> Reported-by: Raslan Darawsheh <rasland@mellanox.com>
> Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> ---
>  drivers/net/mlx4/mlx4_ethdev.c        | 4 +---
>  drivers/net/mlx5/mlx5_ethdev.c        | 4 +---
>  drivers/net/softnic/rte_eth_softnic.c | 4 ++--
>  lib/librte_ethdev/rte_ethdev.c        | 6 ++++++
>  4 files changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/mlx4/mlx4_ethdev.c b/drivers/net/mlx4/mlx4_ethdev.c
> index dfb24c22d0..a18a66cb4a 100644
> --- a/drivers/net/mlx4/mlx4_ethdev.c
> +++ b/drivers/net/mlx4/mlx4_ethdev.c
> @@ -646,9 +646,7 @@ mlx4_dev_infos_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *info)
>  	 */
>  	max = ((priv->device_attr.max_cq > priv->device_attr.max_qp) ?
>  	       priv->device_attr.max_qp : priv->device_attr.max_cq);
> -	/* If max >= 65535 then max = 0, max_rx_queues is uint16_t. */
> -	if (max >= 65535)
> -		max = 65535;
> +	max = RTE_MIN(max, (unsigned int)RTE_MAX_QUEUES_PER_PORT);
>  	info->max_rx_queues = max;
>  	info->max_tx_queues = max;
>  	info->max_mac_addrs = RTE_DIM(priv->mac);
> diff --git a/drivers/net/mlx5/mlx5_ethdev.c b/drivers/net/mlx5/mlx5_ethdev.c
> index d80ae458bc..045dae6b5a 100644
> --- a/drivers/net/mlx5/mlx5_ethdev.c
> +++ b/drivers/net/mlx5/mlx5_ethdev.c
> @@ -617,9 +617,7 @@ mlx5_dev_infos_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *info)
>  	 */
>  	max = RTE_MIN(priv->sh->device_attr.orig_attr.max_cq,
>  		      priv->sh->device_attr.orig_attr.max_qp);
> -	/* If max >= 65535 then max = 0, max_rx_queues is uint16_t. */
> -	if (max >= 65535)
> -		max = 65535;
> +	max = RTE_MIN(max, (unsigned int)RTE_MAX_QUEUES_PER_PORT);
>  	info->max_rx_queues = max;
>  	info->max_tx_queues = max;
>  	info->max_mac_addrs = MLX5_MAX_UC_MAC_ADDRESSES;
> diff --git a/drivers/net/softnic/rte_eth_softnic.c b/drivers/net/softnic/rte_eth_softnic.c
> index 11723778fd..1065cbf847 100644
> --- a/drivers/net/softnic/rte_eth_softnic.c
> +++ b/drivers/net/softnic/rte_eth_softnic.c
> @@ -91,8 +91,8 @@ pmd_dev_infos_get(struct rte_eth_dev *dev __rte_unused,
>  	struct rte_eth_dev_info *dev_info)
>  {
>  	dev_info->max_rx_pktlen = UINT32_MAX;
> -	dev_info->max_rx_queues = UINT16_MAX;
> -	dev_info->max_tx_queues = UINT16_MAX;
> +	dev_info->max_rx_queues = RTE_MAX_QUEUES_PER_PORT;
> +	dev_info->max_tx_queues = RTE_MAX_QUEUES_PER_PORT;
>  
>  	return 0;
>  }
> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
> index 8d2ce31a81..6e9cb243ea 100644
> --- a/lib/librte_ethdev/rte_ethdev.c
> +++ b/lib/librte_ethdev/rte_ethdev.c
> @@ -2986,6 +2986,12 @@ rte_eth_dev_info_get(uint16_t port_id, struct rte_eth_dev_info *dev_info)
>  		return eth_err(port_id, diag);
>  	}
>  
> +	/* Maximum number of queues should be <= RTE_MAX_QUEUES_PER_PORT */
> +	dev_info->max_rx_queues = RTE_MIN(dev_info->max_rx_queues,
> +			RTE_MAX_QUEUES_PER_PORT);
> +	dev_info->max_tx_queues = RTE_MIN(dev_info->max_tx_queues,
> +			RTE_MAX_QUEUES_PER_PORT);
> +
>  	dev_info->driver_name = dev->device->driver->name;
>  	dev_info->nb_rx_queues = dev->data->nb_rx_queues;
>  	dev_info->nb_tx_queues = dev->data->nb_tx_queues;
>