Due to time zone differences, I'll answer for Hyong (below). -john > -----Original Message----- > From: Thomas Monjalon <[email protected]> > Sent: Wednesday, March 13, 2019 1:36 PM > To: Ferruh Yigit <[email protected]>; Hyong Youb Kim (hyonkim) > <[email protected]> > Cc: Andrew Rybchenko <[email protected]>; Qi Zhang > <[email protected]>; [email protected]; John Daley (johndale) > <[email protected]>; Shahaf Shuler <[email protected]>; Jerin Jacob > <[email protected]>; David Marchand > <[email protected]>; Maxime Coquelin > <[email protected]>; Konstantin Ananyev > <[email protected]>; Hemant Agrawal > <[email protected]>; Stephen Hemminger > <[email protected]> > Subject: Re: [PATCH v2] net/enic: add private API to set ingress VLAN rewrite > mode > > 13/03/2019 19:32, Ferruh Yigit: > > On 3/5/2019 7:11 AM, Hyong Youb Kim wrote: > > > The driver currently has a devarg to set the rewrite mode during > > > init. Some apps want to programatically set it after running > > > rte_eal_init() and finding that ports are VIC. Add a private > > > function to support such applications. > > > > It is not good idea to have PMD specific APIs (although we already have > some). > > > > Specific to this case, as far as I can see it is to pass a config > > value and do the action related to it, what would you think having a > > generic key/value set/get API in ethdev for this? Similar to rawdev > get_attr/set_attr [1]? > > > > My concern is it may turn into something like ioctl with many things > > pushed to it, and cause possible duplication ... > > Yes, it is clearly ioctl style. > > Please could you explain more what is the rewrite mode? > Does it apply to the port or the queue? > It applies to a port. By default the Cisco VIC VLAN tags every packet on ingress even if they were untagged coming in on the wire. They are tagged with VLAN 0 or a VLAN id programmed into the NIC depending on the configuration. Its part of the original design, to maintain priority bits, ancient history.
Some apps don't like this (VPP) or take a slower path (OVS). Hyong added a ig-vlan-rewrite=untag devarg to disable this (leave untagged/default vlan packets untagged) during rte_eal_init and this is helpful for OVS, but VPP likes to set the rewrite mode after rte_eal_init() and finding the ports are VIC ports. So that is the reasoning behind the private API call.
