[Intel-wired-lan] [PATCH iwl-net v2] i40e: Fix handling changed priv flags

[Pucha, HimasekharX Reddy]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces at osuosl.org> On Behalf Of pegro at friiks.de
> Sent: 30 October 2024 22:52
> To: intel-wired-lan at lists.osuosl.org; Paul Menzel <pmenzel at molgen.mpg.de>; Nguyen, Anthony L <anthony.l.nguyen at intel.com>; Kitszel, Przemyslaw <przemyslaw.kitszel at intel.com>
> Cc: netdev at vger.kernel.org; Peter Große <pegro at friiks.de>
> Subject: [Intel-wired-lan] [PATCH iwl-net v2] i40e: Fix handling changed priv flags
>
> From: Peter Große <pegro at friiks.de>
>
> After assembling the new private flags on a PF, the operation to determine the changed flags uses the wrong bitmaps. Instead of xor-ing orig_flags with new_flags, it uses the still unchanged pf->flags, thus changed_flags is always 0.
>
> Fix it by using the correct bitmaps.
>
> The issue was discovered while debugging why disabling source pruning stopped working with release 6.7. Although the new flags will be copied to
> pf->flags later on in that function, disabling source pruning requires
> a reset of the PF, which was skipped due to this bug.
>
> Disabling source pruning:
> $ sudo ethtool --set-priv-flags eno1 disable-source-pruning on $ sudo ethtool --show-priv-flags eno1 Private flags for eno1:
> MFP                   : off
> total-port-shutdown   : off
> LinkPolling           : off
> flow-director-atr     : on
> veb-stats             : off
> hw-atr-eviction       : off
> link-down-on-close    : off
> legacy-rx             : off
> disable-source-pruning: on
> disable-fw-lldp       : off
> rs-fec                : off
> base-r-fec            : off
> vf-vlan-pruning       : off
>
> Regarding reproducing:
>
> I observed the issue with a rather complicated lab setup, where
>  * two VLAN interfaces are created on eno1
>  * each with a different MAC address assigned
>  * each moved into a separate namespace
>  * both VLANs are bridged externally, so they form a single layer 2 network
>
> The external bridge is done via a channel emulator adding packet loss and delay and the application in the namespaces tries to send/receive traffic and measure the performance. Sender and receiver are > separated by namespaces, yet the network card "sees its own traffic" send back to it.
> To make that work, source pruning has to be disabled.
>
> Fixes: 70756d0a4727 ("i40e: Use DECLARE_BITMAP for flags and hw_features fields in i40e_pf")
> Signed-off-by: Peter Große <pegro at friiks.de>
> ---
>  drivers/net/ethernet/intel/i40e/i40e_ethtool.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>

Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha at intel.com> (A Contingent worker at Intel)