On 11/4/20 11:39 PM, Thomas Monjalon wrote:
> 04/11/2020 21:19, Ferruh Yigit:
>> On 11/4/2020 5:55 PM, Thomas Monjalon wrote:
>>> 04/11/2020 18:07, Ferruh Yigit:
>>>> On 11/4/2020 4:51 PM, Thomas Monjalon wrote:
>>>>> 03/11/2020 14:29, Ferruh Yigit:
>>>>>> On 11/2/2020 11:48 AM, Ferruh Yigit wrote:
>>>>>>> On 11/2/2020 8:52 AM, SteveX Yang wrote:
>>>>>>>> When the max rx packet length is smaller than the sum of mtu size and
>>>>>>>> ether overhead size, it should be enlarged, otherwise the VLAN packets
>>>>>>>> will be dropped.
>>>>>>>>
>>>>>>>> Fixes: 35b2d13fd6fd ("net: add rte prefix to ether defines")
>>>>>>>>
>>>>>>>> Signed-off-by: SteveX Yang <stevex.y...@intel.com>
>>>>>>>
>>>>>>> Reviewed-by: Ferruh Yigit <ferruh.yi...@intel.com>
>>>>>>
>>>>>> Applied to dpdk-next-net/main, thanks.
>>>>>>
>>>>>> only 1/2 applied since discussion is going on for 2/2.
>>>>>
>>>>> I'm not sure this testpmd change is good.
>>>>>
>>>>> Reminder: testpmd is for testing the PMDs.
>>>>> Don't we want to see VLAN packets dropped in the case described above?
>>>>>
>>>>
>>>> The patch set 'max_rx_pkt_len' in a way to make MTU 1500 for all PMDs,
>>>> otherwise testpmd set hard-coded 'RTE_ETHER_MAX_LEN' value, which makes MTU
>>>> between 1492-1500 depending on PMD.
>>>>
>>>> It is application responsibility to provide correct 'max_rx_pkt_len'.
>>>> I guess the original intention was to set MTU as 1500 but was not correct
>>>> for
>>>> all PMDs and this patch is fixing it.
>>>>
>>>> The same problem in the ethdev, (assuming 'RTE_ETHER_MAX_LEN' will give MTU
>>>> 1500), the other patch in the set is to fix it later.
>>>
>>> OK but the testpmd patch is just hiding the issue, isn't it?
>>>
>>
>> I don't think so, issue was application (testpmd) setting the
>> 'max_rx_pkt_len'
>> wrong.
>>
>> What is hidden?
>
> I was looking for adding a helper in ethdev API.
> But I think I can agree with your way of thinking.
>
The patch breaks running testpmd on Virtio-Net because the
driver populates dev_info.max_rx_pktlen but keeps
dev_info.max_mtu equal to UINT16_MAX as it was filled in by
ethdev. As the result:
Ethdev port_id=0 max_rx_pkt_len 11229 > max valid value 9728
Fail to configure port 0
