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

[Jacob Keller <jacob.e.keller@intel.com>]

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@intel.com>

Regards,
Jake