[dpdk-users] CX4-Lx VF link status in Azure

Mark Bloch markb at mellanox.com
Thu Mar 26 21:09:57 CET 2020

On 3/26/2020 12:00, Benoit Ganne (bganne) wrote:
>> Pasting back this important info:
>> "
>> Note that ethtool and '/sys/class/net/<iface>/speed' also fails
>> to report the link speed (but not the link status).
>> "
>> 26/03/2020 19:27, Benoit Ganne (bganne):
>>> Yes everything is initialized correctly. The netdev itself is configured
>> and usable from Linux (ping etc.). Just removing the over-strict check in
>> mlx5 PMD is enough for everything to work fine:
>> https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgerrit.fd.io%2Fr%2Fc%2Fvpp%2F%2B%2F26152%2F1%2Fbuild%2Fexternal%2Fpatches%2Fdpdk_20.02%2F0&data=02%7C01%7Cmarkb%40mellanox.com%7Ccf7438ae7d924c03b03308d7d1b7fd83%7Ca652971c7d2e4d9ba6a4d149256f461b%7C0%7C0%7C637208460478847341&sdata=fV4wrAvzmHNM88mfCr6lxFXG0ANVOP0rBjfovZii84c%3D&reserved=0
>> 002-mlx5-azure-workaround.patch
>>> The link speed is unknown but this is not issue, and link state and
>> other link info are correctly reported.
>>> Thomas, any input regarding this behavior in mlx5 PMD?
>> I am not aware about the lack of link speed info.
>> It is probably not specific to ConnectX-4 Lx.
>> I guess it happens only with Hyper-V?

Should be fixed by those 3 commits (last 1 one is just cosmetic):



> For me there are 2 separate issues:
>  1) Linux kernel driver does not report link speed in Azure for CX4-Lx in Ubuntu 18.04
>  2) mlx5 PMD enforce that both link speed is defined and link is up to update interface state
> If (1) is fixed, (2) should work, but to me (2) is too strict for no good reason: we do not really care about reported link speed, esp in a virtual environment it usually does not mean much, but we do care about link state.
> ben

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