Re: [dpdk-dev] [PATCH] net/i40e: force promiscuous state after VF reset

[Eelco Chaudron]

On 1 Nov 2019, at 9:12, Eelco Chaudron wrote:

<SNIP>

+       /*
+        * Even though the device reset is successful disabling
promiscuous
+        * mode might not always succeed, causing enabling it after
reset
to

I think we need to root cause why fail to disable promiscuous mode

and
try to fix it first.

I’ve copied in Xiao who helped me identify the issue in your
driver.

The issue is because the change from kernel pf was not synced to DPDK

vf during

the closing period of reset, so we get this failure. Xiao can you add

more details?

The root cause is when kernel pf generate DPDK vf reset event, the
flag

vf->promisc_unicast_enabled will not be cleared but promiscuous mode

is

disabled. When trying to enable promiscuous mode next time by calling

i40evf_dev_promiscuous_enable won't work because it will check the
vf->promisc_unicast_enabled flag first.

static int
i40evf_dev_promiscuous_enable(struct rte_eth_dev *dev)
{
...
    /* If enabled, just return */
    if (vf->promisc_unicast_enabled)
        return 0;
...
}

Hi Eelco,

I think you may need add more detailed message in the commit log or
comments.

My interpretation of the request was that Beilei wanted to know why

disabling promiscuous mode in HW was failing. Beilei can you comment, is

the additional description from Xiao enough?

Yes, promisc_unicast_enabled flag is not cleared during vf reset because fail to disable promiscuous mode, So I think we need to root cause why fail to disable promiscuous mode first.

This patch looks like a workaround but not a fix.

This was debugged together with Xiao and from what I understand is that DPDK fails to reset promiscuous mode in hardware as PF and VF operations are not synced between kernel and DPDK.

Xiao told me this could not be fixed in another way, Xiao can you comment?

Xiao any update you can add to this so it’s more clear for Beilei?

Thanks,

Eelco