Hi Lorenzo,
On 2023-01-18 00:45:44 +0100, Lorenzo Bianconi wrote:
> > Hi Lorenzo and Marek,
> >
> > Thanks for your work.
> >
> > On 2023-01-14 16:54:32 +0100, Lorenzo Bianconi wrote:
> >
> > [...]
> >
> > >
> > > Turn 'hw-offload' feature flag on for:
> > > - netronome (nfp)
> > > - netdevsim.
> >
> > Is there a definition of the 'hw-offload' written down somewhere? From
> > reading this series I take it is the ability to offload a BPF program?
>
> correct
>
> > It would also be interesting to read documentation for the other flags
> > added in this series.
>
> maybe we can add definitions in Documentation/netlink/specs/netdev.yaml?
>
> >
> > [...]
> >
> > > diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
> > > b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
> > > index 18fc9971f1c8..5a8ddeaff74d 100644
> > > --- a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
> > > +++ b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
> > > @@ -2529,10 +2529,14 @@ static void nfp_net_netdev_init(struct nfp_net *nn)
> > > netdev->features &= ~NETIF_F_HW_VLAN_STAG_RX;
> > > nn->dp.ctrl &= ~NFP_NET_CFG_CTRL_RXQINQ;
> > >
> > > + nn->dp.netdev->xdp_features = NETDEV_XDP_ACT_BASIC |
> > > + NETDEV_XDP_ACT_HW_OFFLOAD;
> >
> > If my assumption about the 'hw-offload' flag above is correct I think
> > NETDEV_XDP_ACT_HW_OFFLOAD should be conditioned on that the BPF firmware
> > flavor is in use.
> >
> > nn->dp.netdev->xdp_features = NETDEV_XDP_ACT_BASIC;
> >
> > if (nn->app->type->id == NFP_APP_BPF_NIC)
> > nn->dp.netdev->xdp_features |= NETDEV_XDP_ACT_HW_OFFLOAD;
>
> ack, I will fix it.
Thanks. I have just been informed from Yinjun Zhang that this check is
not enough as this function is reused for VF where nn->app is not set. I
think a better check would be
if (nn->app && nn->app->type->id == NFP_APP_BPF_NIC)
Yinjun also informed me that you can make this code a bit neater by,
s/nn->dp.netdev->xdp_features/netdev->xdp_features/
Thanks again for your work.
>
> >
> > > +
> > > /* Finalise the netdev setup */
> > > switch (nn->dp.ops->version) {
> > > case NFP_NFD_VER_NFD3:
> > > netdev->netdev_ops = &nfp_nfd3_netdev_ops;
> > > + nn->dp.netdev->xdp_features |= NETDEV_XDP_ACT_XSK_ZEROCOPY;
> > > break;
> > > case NFP_NFD_VER_NFDK:
> > > netdev->netdev_ops = &nfp_nfdk_netdev_ops;
> >
> > This is also a wrinkle I would like to understand. Currently NFP support
> > zero-copy on NFD3, but not for offloaded BPF programs. But with the BPF
> > firmware flavor running the device can still support zero-copy for
> > non-offloaded programs.
> >
> > Is it a problem that the driver advertises support for both
> > hardware-offload _and_ zero-copy at the same time, even if they can't be
> > used together but separately?
>
> xdp_features should export NIC supported features in the current
> configuration and it is expected they can be used concurrently.
>
> Regards,
> Lorenzo
>
> >
> > --
> > Kind Regards,
> > Niklas Söderlund
--
Kind Regards,
Niklas Söderlund
