[xdp-hints] Re: [RFC bpf-next v2 10/14] ice: Support rx timestamp metadata for xdp

[Alexander Lobakin <alexandr.lobakin@intel.com>]

From: Stanislav Fomichev <sdf@google.com>
Date: Thu,3 Nov 2022 20:25:28 -0700

> COMPILE-TESTED ONLY!
> 
> Cc: John Fastabend <john.fastabend@gmail.com>
> Cc: David Ahern <dsahern@gmail.com>
> Cc: Martin KaFai Lau <martin.lau@linux.dev>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Willem de Bruijn <willemb@google.com>
> Cc: Jesper Dangaard Brouer <brouer@redhat.com>
> Cc: Anatoly Burakov <anatoly.burakov@intel.com>
> Cc: Alexander Lobakin <alexandr.lobakin@intel.com>
> Cc: Magnus Karlsson <magnus.karlsson@gmail.com>
> Cc: Maryam Tahhan <mtahhan@redhat.com>
> Cc: xdp-hints@xdp-project.net
> Cc: netdev@vger.kernel.org
> Signed-off-by: Stanislav Fomichev <sdf@google.com>
> ---
>  drivers/net/ethernet/intel/ice/ice.h      |  5 ++
>  drivers/net/ethernet/intel/ice/ice_main.c |  1 +
>  drivers/net/ethernet/intel/ice/ice_txrx.c | 75 +++++++++++++++++++++++
>  3 files changed, 81 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h
> index f88ee051e71c..c51a392d64a4 100644
> --- a/drivers/net/ethernet/intel/ice/ice.h
> +++ b/drivers/net/ethernet/intel/ice/ice.h
> @@ -925,6 +925,11 @@ int ice_open_internal(struct net_device *netdev);
>  int ice_stop(struct net_device *netdev);
>  void ice_service_task_schedule(struct ice_pf *pf);
>  
> +struct bpf_insn;
> +struct bpf_patch;
> +void ice_unroll_kfunc(const struct bpf_prog *prog, u32 func_id,
> +		      struct bpf_patch *patch);
> +
>  /**
>   * ice_set_rdma_cap - enable RDMA support
>   * @pf: PF struct
> diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
> index 1f27dc20b4f1..8ddc6851ef86 100644
> --- a/drivers/net/ethernet/intel/ice/ice_main.c
> +++ b/drivers/net/ethernet/intel/ice/ice_main.c
> @@ -9109,4 +9109,5 @@ static const struct net_device_ops ice_netdev_ops = {
>  	.ndo_xdp_xmit = ice_xdp_xmit,
>  	.ndo_xsk_wakeup = ice_xsk_wakeup,
>  	.ndo_get_devlink_port = ice_get_devlink_port,
> +	.ndo_unroll_kfunc = ice_unroll_kfunc,
>  };
> diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.c b/drivers/net/ethernet/intel/ice/ice_txrx.c
> index 1b6afa168501..e9b5e883753e 100644
> --- a/drivers/net/ethernet/intel/ice/ice_txrx.c
> +++ b/drivers/net/ethernet/intel/ice/ice_txrx.c
> @@ -7,6 +7,7 @@
>  #include <linux/netdevice.h>
>  #include <linux/prefetch.h>
>  #include <linux/bpf_trace.h>
> +#include <linux/bpf_patch.h>
>  #include <net/dsfield.h>
>  #include <net/mpls.h>
>  #include <net/xdp.h>
> @@ -1098,8 +1099,80 @@ ice_is_non_eop(struct ice_rx_ring *rx_ring, union ice_32b_rx_flex_desc *rx_desc)
>  
>  struct ice_xdp_buff {
>  	struct xdp_buff xdp;
> +	struct ice_rx_ring *rx_ring;
> +	union ice_32b_rx_flex_desc *rx_desc;
>  };
>  
> +void ice_unroll_kfunc(const struct bpf_prog *prog, u32 func_id,
> +		      struct bpf_patch *patch)
> +{
> +	if (func_id == xdp_metadata_kfunc_id(XDP_METADATA_KFUNC_EXPORT_TO_SKB)) {
> +		return xdp_metadata_export_to_skb(prog, patch);

Hey,

FYI, our team wants to write a follow-up patch with ice support
added, not like a draft, more of a mature code. I'm thinking of
calling ice C function which would process Rx descriptors from
that BPF code from the unrolling callback -- otherwise,
implementing a couple hundred C code lines from ice_txrx_lib.c
would be a bit too much :D

> +	} else if (func_id == xdp_metadata_kfunc_id(XDP_METADATA_KFUNC_RX_TIMESTAMP_SUPPORTED)) {
> +		/* return true; */
> +		bpf_patch_append(patch, BPF_MOV64_IMM(BPF_REG_0, 1));
> +	} else if (func_id == xdp_metadata_kfunc_id(XDP_METADATA_KFUNC_RX_TIMESTAMP)) {

[...]

> -- 
> 2.38.1.431.g37b22c650d-goog

Thanks,
Olek