Re: [dpdk-dev] [PATCH v2 0/7] add Intel DCF PMD support

["Wang, Haiyue" <haiyue.wang@intel.com>]

> -----Original Message-----
> From: Stillwell Jr, Paul M <paul.m.stillwell.jr@intel.com>
> Sent: Tuesday, March 17, 2020 02:55
> To: Zhang, Qi Z <qi.z.zhang@intel.com>; Wang, Haiyue <haiyue.wang@intel.com>; dev@dpdk.org; Ye,
> Xiaolong <xiaolong.ye@intel.com>; Yang, Qiming <qiming.yang@intel.com>; Xing, Beilei
> <beilei.xing@intel.com>
> Cc: Zhao1, Wei <wei.zhao1@intel.com>; Wang, Haiyue <haiyue.wang@intel.com>; Liang, Cunming
> <cunming.liang@intel.com>; Wu, Jingjing <jingjing.wu@intel.com>
> Subject: RE: [dpdk-dev] [PATCH v2 0/7] add Intel DCF PMD support
> 
> See my responses inline.
> 
> Paul
> 
> > -----Original Message-----
> > From: Zhang, Qi Z <qi.z.zhang@intel.com>
> > Sent: Saturday, March 14, 2020 6:50 PM
> > To: Stillwell Jr, Paul M <paul.m.stillwell.jr@intel.com>; Wang, Haiyue
> > <haiyue.wang@intel.com>; dev@dpdk.org; Ye, Xiaolong
> > <xiaolong.ye@intel.com>; Yang, Qiming <qiming.yang@intel.com>; Xing,
> > Beilei <beilei.xing@intel.com>
> > Cc: Zhao1, Wei <wei.zhao1@intel.com>; Wang, Haiyue
> > <haiyue.wang@intel.com>; Liang, Cunming <cunming.liang@intel.com>; Wu,
> > Jingjing <jingjing.wu@intel.com>
> > Subject: RE: [dpdk-dev] [PATCH v2 0/7] add Intel DCF PMD support
> >
> > Hi Paul:
> >
> > > -----Original Message-----
> > > From: Stillwell Jr, Paul M <paul.m.stillwell.jr@intel.com>
> > > Sent: Saturday, March 14, 2020 12:19 AM
> > > To: Wang, Haiyue <haiyue.wang@intel.com>; dev@dpdk.org; Ye, Xiaolong
> > > <xiaolong.ye@intel.com>; Zhang, Qi Z <qi.z.zhang@intel.com>; Yang,
> > > Qiming <qiming.yang@intel.com>; Xing, Beilei <beilei.xing@intel.com>
> > > Cc: Zhao1, Wei <wei.zhao1@intel.com>; Wang, Haiyue
> > > <haiyue.wang@intel.com>
> > > Subject: RE: [dpdk-dev] [PATCH v2 0/7] add Intel DCF PMD support
> > >
> > > I'm confused. Shouldn't the DCF be a separate driver since it is a VF,
> > > not part of a PF? You are starting to combine PF/VF code and I'm not
> > > sure if that is the correct way to go.
> >
> > From DPDK's view, DCF is NOT a VF driver, actually it behaves like a PF driver
> > with control path only and it share most exist PF driver's API implementation
> 
> It *is* a VF. The only way this will work is if the VF has the trust flag set and then it can become
> the DCF. You can't set the trust flag on a PF I don't think. That's the only way this will work
> because the kernel driver code has checks on the admin queue messages to see if the message is from a
> VF. If it's not a message from a specific VF, then the message will get rejected.
> 

This is absolutely right, and this is added into the guide about how to enable DCF. ;-)

And one important thing is that : VF with DCF capability is only bound to ice/kernel
driver, so we can't add it into the generic iavf VF PMD, since it works on i40e/ice etc.
And the main task about DCF is flow control, the AdminQ is implemented in ice PF PMD, and
it just uses these AdminQ API to runs on VF hardware, not ice PF hardware.


> > , That's why we combined it with exist PF driver, so when the module
> > driver/net/ice is compiled into a library, it can be probed as a PF driver or DCF
> > base on device ID at runtime.
> > And the is not special in DPDK, for example, the module in driver/net/i40e
> > can be probed as i40e pf driver or i40e vf driver.
> > DCF take SR-IOV's mailbox as a message channel to communicate with the
> > backend kernel driver, so iavf virtual channel is reused here, so we also need
> > to link iavf share code.
> >
> > And I agree, its always better if we can separate 2 different things while
> > decouple all the common code into a share library to avoid duplicate code
> > copy (just like we did on iavf share code) But in this case, a lot of code
> > refectory is required , so far we just take the simple way, we may improve
> > this in future.
> >
> > Thanks
> > Qi
> >
> > >
> > > Paul
> > >
> > > > -----Original Message-----
> > > > From: dev <dev-bounces@dpdk.org> On Behalf Of Haiyue Wang
> > > > Sent: Monday, March 9, 2020 11:50 PM
> > > > To: dev@dpdk.org; Ye, Xiaolong <xiaolong.ye@intel.com>; Zhang, Qi Z
> > > > <qi.z.zhang@intel.com>; Yang, Qiming <qiming.yang@intel.com>; Xing,
> > > > Beilei <beilei.xing@intel.com>
> > > > Cc: Zhao1, Wei <wei.zhao1@intel.com>; Wang, Haiyue
> > > > <haiyue.wang@intel.com>
> > > > Subject: [dpdk-dev] [PATCH v2 0/7] add Intel DCF PMD support
> > > >
> > > > A DCF (Device Config Function) based approach is proposed where a
> > > > device bound to the device's VF0 can act as a sole controlling
> > > > entity to exercise advance functionality (such as switch, ACL) for rest of
> > the VFs.
> > > >
> > > > The DCF works as a standalone PMD to support this function, which
> > > > shares the ice PMD flow control core function and the iavf virtchnl
> > > > mailbox core module.
> > > >
> > > > This patchset is based on:
> > > > [1] https://patchwork.dpdk.org/cover/66417/ : update ice base code
> > > > [2] https://patchwork.dpdk.org/cover/66472/ : iavf share code update
> > > >
> > > > Depends-on: series-8843
> > > > Depends-on: series-8855
> > > >
> > > > v2:
> > > >    1. update the iavf patchset link.
> > > >    2. split more patches for making this work be more understandable
> > > >    3. fix the log function usage, devargs checking from v1.
> > > >
> > > > Haiyue Wang (7):
> > > >   net/iavf: stop the PCI probe in DCF mode
> > > >   net/ice: add the DCF hardware initialization
> > > >   net/ice: initiate to acquire the DCF capability
> > > >   net/ice: handle the AdminQ command by DCF
> > > >   net/ice: export the DDP definition symbols
> > > >   net/ice: handle the PF initialization by DCF
> > > >   net/ice: get the VF hardware index in DCF
> > > >
> > > >  doc/guides/nics/ice.rst                |  47 ++
> > > >  doc/guides/nics/img/ice_dcf.png        | Bin 0 -> 39168 bytes
> > > >  doc/guides/rel_notes/release_20_05.rst |   5 +
> > > >  drivers/common/Makefile                |   1 +
> > > >  drivers/net/iavf/iavf_ethdev.c         |  43 ++
> > > >  drivers/net/ice/Makefile               |   6 +
> > > >  drivers/net/ice/ice_dcf.c              | 651
> > > +++++++++++++++++++++++++
> > > >  drivers/net/ice/ice_dcf.h              |  61 +++
> > > >  drivers/net/ice/ice_dcf_ethdev.c       | 321 ++++++++++++
> > > >  drivers/net/ice/ice_dcf_ethdev.h       |  33 ++
> > > >  drivers/net/ice/ice_dcf_parent.c       | 344 +++++++++++++
> > > >  drivers/net/ice/ice_ethdev.c           |   9 +-
> > > >  drivers/net/ice/ice_ethdev.h           |   8 +
> > > >  drivers/net/ice/meson.build            |   8 +-
> > > >  mk/rte.app.mk                          |   1 +
> > > >  15 files changed, 1528 insertions(+), 10 deletions(-)  create mode
> > > > 100644 doc/guides/nics/img/ice_dcf.png  create mode 100644
> > > > drivers/net/ice/ice_dcf.c  create mode 100644
> > > > drivers/net/ice/ice_dcf.h create mode 100644
> > > > drivers/net/ice/ice_dcf_ethdev.c  create mode 100644
> > > > drivers/net/ice/ice_dcf_ethdev.h  create mode 100644
> > > > drivers/net/ice/ice_dcf_parent.c
> > > >
> > > > --
> > > > 2.25.1
> > >
> >
>