Re: DEV_RX_OFFLOAD_VLAN_EXTEND offload

[Jerin Jacob <jerin.jacob@caviumnetworks.com>]

-----Original Message-----
> Date: Thu, 1 Nov 2018 09:50:12 +0000
> From: "Zhao1, Wei" <wei.zhao1@intel.com>
> To: Jerin Jacob <jerin.jacob@caviumnetworks.com>, "Yigit, Ferruh"
>  <ferruh.yigit@intel.com>
> CC: "dev@dpdk.org" <dev@dpdk.org>, "thomas@monjalon.net"
>  <thomas@monjalon.net>, "arybchenko@solarflare.com"
>  <arybchenko@solarflare.com>, "olivier.matz@6wind.com"
>  <olivier.matz@6wind.com>, "Zhang, Qi Z" <qi.z.zhang@intel.com>, "Xing,
>  Beilei" <beilei.xing@intel.com>, "Lu, Wenzhuo" <wenzhuo.lu@intel.com>,
>  "Ananyev, Konstantin" <konstantin.ananyev@intel.com>
> Subject: RE: [dpdk-dev] DEV_RX_OFFLOAD_VLAN_EXTEND offload
> 
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Jerin Jacob
> > Sent: Friday, October 26, 2018 10:35 PM
> > To: Yigit, Ferruh <ferruh.yigit@intel.com>
> > Cc: dev@dpdk.org; thomas@monjalon.net; arybchenko@solarflare.com;
> > olivier.matz@6wind.com; Zhang, Qi Z <qi.z.zhang@intel.com>; Xing, Beilei
> > <beilei.xing@intel.com>; Lu, Wenzhuo <wenzhuo.lu@intel.com>; Ananyev,
> > Konstantin <konstantin.ananyev@intel.com>
> > Subject: Re: [dpdk-dev] DEV_RX_OFFLOAD_VLAN_EXTEND offload
> >
> > -----Original Message-----
> > > Date: Fri, 26 Oct 2018 14:40:42 +0100
> > > From: Ferruh Yigit <ferruh.yigit@intel.com>
> > > To: Jerin Jacob <jerin.jacob@caviumnetworks.com>, "dev@dpdk.org"
> > >  <dev@dpdk.org>
> > > CC: "thomas@monjalon.net" <thomas@monjalon.net>,
> > > "arybchenko@solarflare.com" <arybchenko@solarflare.com>,
> > > "olivier.matz@6wind.com" <olivier.matz@6wind.com>,
> > "qi.z.zhang@intel.com"
> > >  <qi.z.zhang@intel.com>, "beilei.xing@intel.com"
> > > <beilei.xing@intel.com>,  Wenzhuo Lu <wenzhuo.lu@intel.com>,
> > > Konstantin Ananyev  <konstantin.ananyev@intel.com>
> > > Subject: Re: [dpdk-dev] DEV_RX_OFFLOAD_VLAN_EXTEND offload
> > > User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0)
> > > Gecko/20100101
> > >  Thunderbird/52.9.1
> > >
> > >
> > > On 10/26/2018 11:56 AM, Jerin Jacob wrote:
> > > >
> > > > Does anyone know the expectation of
> > DEV_RX_OFFLOAD_VLAN_EXTEND
> > > > offload? Does not look like it is documented.
> > > >
> > > > Looks like it is very specific to Intel controllers, Based on 82599
> > > > HRM, it is following, not sure what is the real expectation from NIC
> > > > in normative terms.
> > > >
> > > > Extended VLAN.
> > > > -------------
> > > > When set, all incoming Rx packets are expected to have at least one
> > > > VLAN with the Ether type as defined in EXVET register. The packets
> > > > can have an inner-VLAN that should be used for all filtering
> > > > purposes. All Tx packets are expected to have at least one VLAN
> > > > added to them by the host. In the case of an additional VLAN request
> > > > (VLE), the inner-VLAN is added by the hardware after the outer-VLAN is
> > added by the host.
> > > > This bit should only be reset by a PCIe reset and should only be
> > > > changed while Tx and Rx processes are stopped.
> > > > The exception to this rule are MAC control packets such as flow
> > > > control, 802.1x, LACP, etc. that never carry a VLAN tag of any type
> > > >
> > >
> > > This looks similar to QinQ but it seems not, in ixgbe datasheet it has:
> >
> > Yes. QinQ there is an already an offload called
> > DEV_RX_OFFLOAD_QINQ_STRIP
> 
> Excuse me, I have some thought, is that right?
> maybe DEV_RX_OFFLOAD_QINQ_STRIP and DEV_RX_OFFLOAD_VLAN_EXTEND is just two thing that play a different role each.
> DEV_RX_OFFLOAD_VLAN_EXTEND tell NIC to recognize QinQ PACKETS, it is a filter for NIC.
> DEV_RX_OFFLOAD_QINQ_STRIP tell nic to strip 2 inner and outer vlan head when moving packets from nic to host memory.
> I40e NIC is the normative terms when handling qinq packets.

Yes, it makes sense if the meaning of DEV_RX_OFFLOAD_VLAN_EXTEND is QINQ
filter. But it looks like not, as .vlan_filter_set ethdev callback accepts 
only single vlan id as "uint16_t vlan_id".
If it needs to be treated as QinQ filter then QinQ vlan_ids needs to be
send to driver through some means.


Probably we may need to deprecate these vlan API in long-term and
enable it through rte_flow.

> 
> >
> >
> > >
> > > "
> > > Double VLAN and Single VLAN Support
> > > -----------------------------------
> > > <....>
> > >  This mode is used for systems where the near end switch adds the
> > > outer VLAN header containing switching information.
> > > <...>
> > > "
> > >
> > > And it in this mode hw doesn't insert or strip the outer VLAN, it
> > > expect SW does it. The ethernet type is not 0x88A8 but can be anything
> > > set on EXVET.VET_EXT. So looks like it is to let switch to add custom VLAN
> > tags and NIC to ignore them.