Re: [dpdk-dev] [PATCH] app/testpmd: fix RSS key

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

On 1/18/2021 8:59 AM, Zhang,Alvin wrote:
> From: Alvin Zhang <alvinx.zhang@intel.com>
> 
> Since the patch '1848b117' has set the value of key in 'struct
> rte_flow_action_rss' to NULL, the PMD cannot get the RSS key now.
> 
> This patch sets offset and size of the key pointer as the first
> parameter of the token 'key' and copies the start address of the
> 'HEX' data to the location specified by the first parameter of
> the token.
> 

Can you please put the rte_flow command that enables reproducing this defect, it 
may help in the future?

> Fixes: 1848b117cca1 ("app/testpmd: fix RSS key for flow API RSS rule")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Alvin Zhang <alvinx.zhang@intel.com>
> ---
>   app/test-pmd/cmdline_flow.c | 24 +++++++++++++-----------
>   1 file changed, 13 insertions(+), 11 deletions(-)
> 
> diff --git a/app/test-pmd/cmdline_flow.c b/app/test-pmd/cmdline_flow.c
> index 585cab9..6eb46d3 100644
> --- a/app/test-pmd/cmdline_flow.c
> +++ b/app/test-pmd/cmdline_flow.c
> @@ -3403,7 +3403,10 @@ static int comp_set_sample_index(struct context *, const struct token *,
>   		.name = "key",
>   		.help = "RSS hash key",
>   		.next = NEXT(action_rss, NEXT_ENTRY(HEX)),
> -		.args = ARGS(ARGS_ENTRY_ARB(0, 0),
> +		.args = ARGS(ARGS_ENTRY_ARB
> +			     (offsetof(struct action_rss_data, conf) +
> +			      offsetof(struct rte_flow_action_rss, key),
> +			      sizeof(((struct rte_flow_action_rss *)0)->key)),


+1, it is required to write the address, and I confirm this enables getting 
'key' value to the PMD.

>   			     ARGS_ENTRY_ARB
>   			     (offsetof(struct action_rss_data, conf) +
>   			      offsetof(struct rte_flow_action_rss, key_len),
> @@ -6495,19 +6498,18 @@ static int comp_set_sample_index(struct context *, const struct token *,
>   	if (ctx->objmask)
>   		memset((uint8_t *)ctx->objmask + arg_data->offset,
>   					0xff, hexlen);
> +
>   	/* Save address if requested. */
>   	if (arg_addr->size) {
> -		memcpy((uint8_t *)ctx->object + arg_addr->offset,
> -		       (void *[]){
> -			(uint8_t *)ctx->object + arg_data->offset
> -		       },
> -		       arg_addr->size);
> +		if (arg_addr->size < sizeof(void *))
> +			goto error;

Above two lines seems only actual change in this function, others are 
refactoring the assignment.

1) why this check required, I think we can ignore it.
2) What do you think to remove the refactoring to reduce the change to the 
actual fix?

> +
> +		*(void **)((uint8_t *)ctx->object + arg_addr->offset) =
> +				(uint8_t *)ctx->object + arg_data->offset;
> +
>   		if (ctx->objmask)
> -			memcpy((uint8_t *)ctx->objmask + arg_addr->offset,
> -			       (void *[]){
> -				(uint8_t *)ctx->objmask + arg_data->offset
> -			       },
> -			       arg_addr->size);
> +			*(void **)((uint8_t *)ctx->objmask + arg_addr->offset) =
> +				(uint8_t *)ctx->objmask + arg_data->offset;
>   	}
>   	return len;
>   error:
>