Re: [dpdk-dev] [PATCH v4] app/testpmd: fix the default RSS key configuration

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

On 9/24/2020 2:45 PM, Lijun Ou wrote:
> It use the NIC valid default RSS key instead of the testpmd
> dummy RSS key in the flow configuration when the RSS key is
> not specified in the flow rule. If the NIC RSS key is
> invalid, it will use testpmd dummy RSS key as the default
> key.

Can you please describe the impact, what fails without this fix?

> 
> Fixes: ac8d22de2394 ("ethdev: flatten RSS configuration in flow API")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Lijun Ou <oulijun@huawei.com>
> ---
> V3->V4:
> -fix checkpatch warning and shorter commit content.
> 
> V2->V3:
> -fix checkpatch warning.
> 
> V1->V2:
> -fix the commit.
> ---
>   app/test-pmd/cmdline_flow.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
> 
> diff --git a/app/test-pmd/cmdline_flow.c b/app/test-pmd/cmdline_flow.c
> index 6263d30..e6648da 100644
> --- a/app/test-pmd/cmdline_flow.c
> +++ b/app/test-pmd/cmdline_flow.c
> @@ -4312,6 +4312,7 @@ parse_vc_action_rss(struct context *ctx, const struct token *token,
>   		action_rss_data->queue[i] = i;
>   	if (!port_id_is_invalid(ctx->port, DISABLED_WARN) &&
>   	    ctx->port != (portid_t)RTE_PORT_ALL) {
> +		struct rte_eth_rss_conf rss_conf = {0};
>   		struct rte_eth_dev_info info;
>   		int ret2;
>   
> @@ -4322,6 +4323,13 @@ parse_vc_action_rss(struct context *ctx, const struct token *token,
>   		action_rss_data->conf.key_len =
>   			RTE_MIN(sizeof(action_rss_data->key),
>   				info.hash_key_size);
> +
> +		rss_conf.rss_key_len = sizeof(action_rss_data->key);
> +		rss_conf.rss_key = action_rss_data->key;

'rss_conf.rss_key_len' is the input parameter, it looks like it has been used as 
the size of the 'rss_key', but as far as I can see it is not.

Because of this if 'info.hash_key_size' is bigger than 
'sizeof(action_rss_data->key)', won't PMD overwrite the stack for the remaining 
bytes?

Can you please check?

> +		ret2 = rte_eth_dev_rss_hash_conf_get(ctx->port, &rss_conf);
> +		if (ret2 != 0)
> +			return ret2;

If PMD not implemented the 'rss_hash_conf_get' dev_ops, should it fail the RSS 
action?

> +		action_rss_data->conf.key = rss_conf.rss_key;
>   	}
>   	action->conf = &action_rss_data->conf;
>   	return ret;
>