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

[oulijun <oulijun@huawei.com>]

在 2020/9/30 20:57, Ferruh Yigit 写道:
> 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?
> 
Hi, Ferruh
   According to Phil Yang's suggestion, I've put the impact description 
in the cover letter.
    When a user runs a flow create cmd to configure an RSS rule
with specifying the empty rss actions in testpmd, this mean
that the flow gets the default RSS functions from the valid
NIC default RSS hash key. However, the testpmd is not set
the default RSS key incorrectly when RSS key is not specified
in flow create cmd.
    After the testpmd is started, run the flow create cmd without 
specifying the RSS hash key. Ensure that RSS hash key queried after
the RSS flow is configured is the same as the default key after the
testpmd is start.

>>
>> 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.
> 
Yes, rss_key_len and rss_key is configured independently. In fact, when 
the user configures the rss_key， we should know rss_key_len.
> 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?
if info.hash_key_size and action_rss_data->key is set used RSS flow cmd 
when info.hash_key_size is bigger than sizeof(action_rss_data->key)， the 
driver will return an error.
> 
> 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?
Yes, When the RSS hash key is not specified in the RSS flow, ensure that 
the RSS hash key remains unchanged and is the same as that configured in 
the hardware when the testpmd is started.
> 
>> +        action_rss_data->conf.key = rss_conf.rss_key;
>>       }
>>       action->conf = &action_rss_data->conf;
>>       return ret;
>>
> 
> .
>