Re: Reg: Link Bonding of VFs and PF admin down

[Stephen Hemminger <stephen@networkplumber.org>]

On Wed, 29 Mar 2023 12:27:16 +0530
bharath paulraj <bharathpaul@gmail.com> wrote:

> Hello Team,
> 
> I have two X710 NICs in the hypervisor and created the VFs on those NICs.
> PF is managed by the Linux kernel, while the VF is managed by DPDK. I am
> using the "test-pmd" application to test the bonding functionality,
> especially ACTIVE-BACKUP mode.
> I have created the bond interface and added the slaves in such a way that
> the one VFs from each of the PF is added to the bond interface. The goal is
> to achieve uninterrupted traffic flow even when one of the PF is down.
> As part of my testing, I made one of the PF admin down using the command
> "ip link set <interface> down". Even after waiting for a few minutes, the
> link status is not propagated to the VF, and the link bonding still takes
> the PF which is down as the primary slave and tries to send the packet out
> of that interface.
> 
> While debugging I found out that the link status of VF is still up. Is this
> the expected behaviour? As per the link:
> https://www.intel.in/content/www/in/en/support/articles/000036776/ethernet-products.html
> it is the expected behaviour. It may work well if the use case is VF-to-VF
> communication. But if the use case is to communicate to the other system -
> (Switch/Routers), then this behaviour will break the link bonding
> functionality, as the peer's interface would be operationally down, once
> the PF is made admin down.
> 
> 
> My use case:  PF is managed by Linux kernel is connected to the external
> Router, VF is added to the VM, and the DPDK application is supposed to
> send/read the packet from the VF.

Link state is controlled by Linux kernel driver, the DPDK driver
is just reflecting information from the kernel. Talk to the kernel
maintainers and/or Redhat.