[Intel-wired-lan] [next PATCH 11/11] igb: Add workaround for VLAN tag stripping on 82576

Brown, Aaron F aaron.f.brown at intel.com
Thu Jan 14 03:17:56 UTC 2016


> From: Intel-wired-lan [intel-wired-lan-bounces at lists.osuosl.org] on behalf of Alexander Duyck [aduyck at mirantis.com]
> Sent: Wednesday, January 06, 2016 11:11 PM
> To: intel-wired-lan at lists.osuosl.org
> Subject: [Intel-wired-lan] [next PATCH 11/11] igb: Add workaround for VLAN tag stripping on 82576
> 
> There was a workaround partially implemented for the 82576 that is needed
> in order for VLAN tag stripping to function correctly.  The original code
> had side effects that would make it so the workaround was active on all
> MACs.  I have updated the code so that the workaround is enabled, but
> limited to the 82576, or activated if we exceed the available unicast
> addresses.
> 
> The workaround has a side effect of mirroring all of the traffic outgoing
> from the VFs back to the PF.  As such it is not recommended to use the
> 82576 in promiscuous mode as it will take a performance hit, though this is
> now consistent with the performance as seen on the out-of-tree igb driver.
> 
> I also limited the scope of the UTA bits all being set to only when the
> VMOLR register is enabled.  This should limit the effects of the UTA
> register so that we don't pick up any excess traffic unless promiscuous mode
> has been enabled on the PF, whereas before the PF would have ended up in
> something equivalent to unicast promiscuous mode with VLAN filtering
> otherwise.
> 
> Signed-off-by: Alexander Duyck <aduyck at mirantis.com>
> ---
>  drivers/net/ethernet/intel/igb/e1000_82575.c |    2 ++
>  drivers/net/ethernet/intel/igb/igb_main.c    |   26 ++++++++++++++------------
>  2 files changed, 16 insertions(+), 12 deletions(-)

Tested-by: Aaron Brown <aaron.f.brown at intel.com>


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