[PATCH iwl-net] iavf: fix wrong VLAN mask for legacy Rx descriptors L2TAG2

[Petr Oros <poros@redhat.com>]

The IAVF_RXD_LEGACY_L2TAG2_M mask was incorrectly defined as
GENMASK_ULL(63, 32), extracting 32 bits from qw2 instead of the
16-bit VLAN tag. In the legacy Rx descriptor layout, the 2nd L2TAG2
(VLAN tag) occupies bits 63:48 of qw2, not 63:32.

The oversized mask causes FIELD_GET to return a 32-bit value where the
actual VLAN tag sits in bits 31:16. When this value is passed to
iavf_receive_skb() as a u16 parameter, it gets truncated to the lower
16 bits (which contain the 1st L2TAG2, typically zero). As a result,
__vlan_hwaccel_put_tag() is never called and software VLAN interfaces
on VFs receive no traffic.

This affects VFs behind ice PF (VIRTCHNL VLAN v2) when the PF
advertises VLAN stripping into L2TAG2_2 and legacy descriptors are
used.

The flex descriptor path already uses the correct mask
(IAVF_RXD_FLEX_L2TAG2_2_M = GENMASK_ULL(63, 48)).

Fixes: 2dc8e7c36d80 ("iavf: refactor iavf_clean_rx_irq to support legacy and flex descriptors")
Signed-off-by: Petr Oros <poros@redhat.com>
---
 drivers/net/ethernet/intel/iavf/iavf_type.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/iavf/iavf_type.h b/drivers/net/ethernet/intel/iavf/iavf_type.h
index 1d8cf29cb65ac5..5bb1de1cfd33b1 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_type.h
+++ b/drivers/net/ethernet/intel/iavf/iavf_type.h
@@ -277,7 +277,7 @@ struct iavf_rx_desc {
 /* L2 Tag 2 Presence */
 #define IAVF_RXD_LEGACY_L2TAG2P_M		BIT(0)
 /* Stripped S-TAG VLAN from the receive packet */
-#define IAVF_RXD_LEGACY_L2TAG2_M		GENMASK_ULL(63, 32)
+#define IAVF_RXD_LEGACY_L2TAG2_M		GENMASK_ULL(63, 48)
 /* Stripped S-TAG VLAN from the receive packet */
 #define IAVF_RXD_FLEX_L2TAG2_2_M		GENMASK_ULL(63, 48)
 /* The packet is a UDP tunneled packet */
-- 
2.52.0