RE: [PATCH v2] net/iavf: fix mismatch between rx_pkt_burst and RX descriptor

["Zhang, Qi Z" <qi.z.zhang@intel.com>]

> -----Original Message-----
> From: Zhang, Qi Z <qi.z.zhang@intel.com>
> Sent: Wednesday, May 11, 2022 8:04 AM
> To: Zhang, Qi Z <qi.z.zhang@intel.com>; Zhou, YidingX
> <yidingx.zhou@intel.com>; dev@dpdk.org; Wu, Jingjing
> <jingjing.wu@intel.com>; Xing, Beilei <beilei.xing@intel.com>
> Cc: Yang, Qiming <qiming.yang@intel.com>; stable@dpdk.org; Yeleswarapu,
> Ramamani <ramamani.yeleswarapu@intel.com>
> Subject: RE: [PATCH v2] net/iavf: fix mismatch between rx_pkt_burst and RX
> descriptor
> 
> 
> 
> > -----Original Message-----
> > From: Zhang, Qi Z <qi.z.zhang@intel.com>
> > Sent: Monday, May 9, 2022 10:05 AM
> > To: Zhou, YidingX <yidingx.zhou@intel.com>; dev@dpdk.org; Wu, Jingjing
> > <jingjing.wu@intel.com>; Xing, Beilei <beilei.xing@intel.com>
> > Cc: Yang, Qiming <qiming.yang@intel.com>; stable@dpdk.org;
> > Yeleswarapu, Ramamani <ramamani.yeleswarapu@intel.com>
> > Subject: RE: [PATCH v2] net/iavf: fix mismatch between rx_pkt_burst
> > and RX descriptor
> >
> >
> >
> > > -----Original Message-----
> > > From: Zhou, YidingX <yidingx.zhou@intel.com>
> > > Sent: Sunday, May 8, 2022 3:53 AM
> > > To: dev@dpdk.org; Wu, Jingjing <jingjing.wu@intel.com>; Xing, Beilei
> > > <beilei.xing@intel.com>
> > > Cc: Yang, Qiming <qiming.yang@intel.com>; Zhang, Qi Z
> > > <qi.z.zhang@intel.com>; stable@dpdk.org; Yeleswarapu, Ramamani
> > > <ramamani.yeleswarapu@intel.com>
> > > Subject: [PATCH v2] net/iavf: fix mismatch between rx_pkt_burst and
> > > RX descriptor
> 
> Refined the title to " fix wrong data path selection which cause segment fault"
> In dpdk-next-net-intel to make it clear what it is going to fix.

Further refine the commit log in dpdk-next-net-intel as below base on Thomas's comment:

If PF driver don't support a flex Rx descriptor that required by VF,
legacy descriptor format will be negotiated to configure the hardware
queue.

The patch fixes the issue when an Rx data path that handle flexible
descriptor  (e.g.:
iavf_recv_scattered_pkts_vec_avx512_flex_rxd) is selected while the
actual hardware queues are configured as legacy due to above scenario,
which will cause following coredump.

> 
> > >
> > > Some kernel drivers return the capability
> > > VIRTCHNL_VF_OFFLOAD_RX_FLEX_DESC when
> IAVF_RXDID_COMMS_OVS_1
> > is not
> > > supported. This causes PMD to use rx_pkt_burst that handles the Flex
> > > Receive Descriptor format, but actually configures the RXDID into
> > > IAVF_RXDID_LEGACY_1, then the fields of rte_mbuf Will be filled with
> > > wrong values in rx_pkt_burst, which will eventually lead to coredump.
> > >
> > > This patch fixes mismatch between rx_pkt_burst and rx descriptor.
> > >
> > > Fixes: 12b435bf8f2f ("net/iavf: support flex desc metadata
> > > extraction")
> > > Cc: stable@dpdk.org
> > >
> > > Signed-off-by: Yiding Zhou <yidingx.zhou@intel.com>
> >
> > Acked-by: Qi Zhang <qi.z.zhang@intel.com>
> >
> > Applied to dpdk-next-net-intel.
> >
> > Thanks
> > Qi