[PATCH] net/iavf: fix VLAN offload with AVX512

[Lu, Wenzhuo]

> -----Original Message-----
> From: Michal Schmidt <mschmidt at redhat.com>
> Sent: Monday, March 27, 2023 6:08 PM
> To: dev at dpdk.org
> Cc: Richardson, Bruce <bruce.richardson at intel.com>; Konstantin Ananyev
> <konstantin.v.ananyev at yandex.ru>; Wu, Jingjing <jingjing.wu at intel.com>;
> Xing, Beilei <beilei.xing at intel.com>; Rong, Leyi <leyi.rong at intel.com>; Lu,
> Wenzhuo <wenzhuo.lu at intel.com>; stable at dpdk.org
> Subject: [PATCH] net/iavf: fix VLAN offload with AVX512
> 
> It has been observed that mbufs of some received VLAN packets had the VLAN
> tag correctly set in vlan_tci, but ol_flags were missing the VLAN-indicating
> flags.
> 
> _mm256_shuffle_epi8 operates as two independent 128-bit operations, not as
> a single 256-bit operation. To have the RTE_MBUF_F_RX_VLAN* flags reflected
> in the resulting vlan_flags for all 8 rx descriptors, the input l2tag2_flags_shuf
> must contain the required pattern in both 128-bit halves.
> 
> This fix is for the AVX512 Rx path. The same bug in AVX2 was fixed by commit
> eb24917428a1 ("net/iavf: fix VLAN offload with AVX2").
> 
> Fixes: 4b64ccb328c9 ("net/iavf: fix VLAN extraction in AVX512 path")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Michal Schmidt <mschmidt at redhat.com>
Acked-by: Wenzhuo Lu <wenzhuo.lu at intel.com>