RE: [Intel-wired-lan] [PATCH iwl-net v2] iavf: fix wrong VLAN mask for legacy Rx descriptors L2TAG2

[Romanowski, Rafal]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@xxxxxxxxxx> On Behalf Of Jacob
> Keller
> Sent: Tuesday, March 24, 2026 12:07 AM
> To: Oros, Petr <poros@xxxxxxxxxx>; netdev@xxxxxxxxxxxxxxx
> Cc: Paul Menzel <pmenzel@xxxxxxxxxxxxx>; Kitszel, Przemyslaw
> <przemyslaw.kitszel@xxxxxxxxx>; Eric Dumazet <edumazet@xxxxxxxxxx>; linux-
> kernel@xxxxxxxxxxxxxxx; Loktionov, Aleksandr <aleksandr.loktionov@xxxxxxxxx>;
> Andrew Lunn <andrew+netdev@xxxxxxx>; Nguyen, Anthony L
> <anthony.l.nguyen@xxxxxxxxx>; Mateusz Polchlopek
> <mateusz.polchlopek@xxxxxxxxx>; Jakub Kicinski <kuba@xxxxxxxxxx>; Paolo
> Abeni <pabeni@xxxxxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>; intel-
> wired-lan@xxxxxxxxxxxxxxxx
> Subject: Re: [Intel-wired-lan] [PATCH iwl-net v2] iavf: fix wrong VLAN mask for
> legacy Rx descriptors L2TAG2
> 
> On 3/23/2026 3:15 AM, Petr Oros wrote:
> > The reproducer requires legacy Rx descriptors. On modern ice + iavf
> > with full PTP support, flex descriptors are always negotiated and the
> > buggy legacy path is never reached. Flex descriptors require all of:
> >  - CONFIG_PTP_1588_CLOCK enabled
> >  - VIRTCHNL_VF_OFFLOAD_RX_FLEX_DESC granted by PF
> >  - PTP capabilities negotiated (VIRTCHNL_VF_CAP_PTP)
> >  - VIRTCHNL_1588_PTP_CAP_RX_TSTAMP supported
> >  - VIRTCHNL_RXDID_2_FLEX_SQ_NIC present in DDP profile
> >
> > If any condition is not met, iavf_select_rx_desc_format() falls back
> > to legacy descriptors (RXDID=1) and the wrong L2TAG2 mask is hit.
> >
> 
> > Fixes: 2dc8e7c36d80 ("iavf: refactor iavf_clean_rx_irq to support
> > legacy and flex descriptors")
> 
> Sure enough, this commit changed the legacy version to:
> +/* Stripped S-TAG VLAN from the receive packet */
> +#define IAVF_RXD_LEGACY_L2TAG2_M               GENMASK_ULL(63, 32)
> 
> I guess since we basically always negotiated flexible descriptors after this that we
> never caught it.
> 
> Thanks for the fix.
> 
> Reviewed-by: Jacob Keller <jacob.e.keller@xxxxxxxxx>
> 
> Regards,
> Jake

Tested-by: Rafal Romanowski <rafal.romanowski@xxxxxxxxx>