Re: [dpdk-dev] [PATCH v3 18/22] net/ena: move default RSS key to shared mem

[Stanislaw Kardach <kda@semihalf.com>]

On Thu, May 06, 2021 at 04:25:22PM +0200, Michal Krawczyk wrote:
> From: Stanislaw Kardach <kda@semihalf.com>
> 
> Make sure the same random generated RSS key is available to all ENA PMD
> instances in all processes.
> 
> Signed-off-by: Stanislaw Kardach <kda@semihalf.com>
> Reviewed-by: Michal Krawczyk <mk@semihalf.com>
> Reviewed-by: Igor Chauskin <igorch@amazon.com>
> Reviewed-by: Shay Agroskin <shayagr@amazon.com>
> ---
>  drivers/net/ena/ena_ethdev.c | 16 +++++-----------
>  drivers/net/ena/ena_ethdev.h |  1 +
>  2 files changed, 6 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/net/ena/ena_ethdev.c b/drivers/net/ena/ena_ethdev.c
> index 0780e2fee2..5c365e1ab5 100644
> --- a/drivers/net/ena/ena_ethdev.c
> +++ b/drivers/net/ena/ena_ethdev.c
> @@ -276,19 +276,9 @@ static const struct eth_dev_ops ena_dev_ops = {
>  
>  void ena_rss_key_fill(void *key, size_t size)
>  {
> -	static bool key_generated;
> -	static uint8_t default_key[ENA_HASH_KEY_SIZE];
> -	size_t i;
> -
>  	RTE_ASSERT(size <= ENA_HASH_KEY_SIZE);
>  
> -	if (!key_generated) {
> -		for (i = 0; i < ENA_HASH_KEY_SIZE; ++i)
> -			default_key[i] = rte_rand() & 0xff;
> -		key_generated = true;
> -	}
> -
> -	rte_memcpy(key, default_key, size);
> +	rte_memcpy(key, ena_shared_data->default_key, size);
>  }
>  
>  static inline void ena_rx_mbuf_prepare(struct rte_mbuf *mbuf,
> @@ -1758,7 +1748,11 @@ static uint32_t ena_calc_max_io_queue_num(struct ena_com_dev *ena_dev,
>  
>  static void ena_prepare_shared_data(struct ena_shared_data *shared_data)
>  {
> +	size_t i;
> +
>  	memset(shared_data, 0, sizeof(*shared_data));
> +	for (i = 0; i < ENA_HASH_KEY_SIZE; ++i)
> +		shared_data->default_key[i] = rte_rand() & 0xff;
>  }
>  
>  static int ena_shared_data_init(void)
> diff --git a/drivers/net/ena/ena_ethdev.h b/drivers/net/ena/ena_ethdev.h
> index e8858c6118..1f7383dce0 100644
> --- a/drivers/net/ena/ena_ethdev.h
> +++ b/drivers/net/ena/ena_ethdev.h
> @@ -209,6 +209,7 @@ struct ena_offloads {
>  
>  /* Holds data shared between all instances of ENA PMD. */
>  struct ena_shared_data {
> +	uint8_t default_key[ENA_HASH_KEY_SIZE];
Given Ferruh's comments on "[PATCH 17/22] net/ena: support SMP for mz
alloc counter" it is probably a better idea to have this default key
generated per-device and keep it in rte_eth_dev.data. This will allow to
eliminate the shared memory segment (freeing issues) and increase
entropy for the different devices.
>  	/* Each rte_memzone should have unique name.
>  	 * To satisfy it, count number of allocation and add it to name.
>  	 */
> -- 
> 2.25.1
> 

-- 
Best Regards,
Stanislaw Kardach