[xdp-hints] Re: [PATCH RESEND bpf-next 07/15] ice: Support RX hash XDP hint

[Larysa Zaremba <larysa.zaremba@intel.com>]

On Fri, May 12, 2023 at 11:22:05AM -0700, Stanislav Fomichev wrote:
> On 05/12, Larysa Zaremba wrote:
> > RX hash XDP hint requests both hash value and type.
> > Type is XDP-specific, so we need a separate way to map
> > these values to the hardware ptypes, so create a lookup table.
> > 
> > Instead of creating a new long list, reuse contents
> > of ice_decode_rx_desc_ptype[] through preprocessor.
> > 
> > Current hash type enum does not contain ICMP packet type,
> > but ice devices support it, so also add a new type into core code.
> > 
> > Then use previously refactored code and create a function
> > that allows XDP code to read RX hash.
> > 
> > Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
> > ---
> >  .../net/ethernet/intel/ice/ice_lan_tx_rx.h    | 412 +++++++++---------
> >  drivers/net/ethernet/intel/ice/ice_txrx_lib.c |  72 +++
> >  include/net/xdp.h                             |   3 +
> >  3 files changed, 283 insertions(+), 204 deletions(-)
> > 
> > diff --git a/drivers/net/ethernet/intel/ice/ice_lan_tx_rx.h b/drivers/net/ethernet/intel/ice/ice_lan_tx_rx.h
> > index 89f986a75cc8..d384ddfcb83e 100644
> > --- a/drivers/net/ethernet/intel/ice/ice_lan_tx_rx.h
> > +++ b/drivers/net/ethernet/intel/ice/ice_lan_tx_rx.h
> > @@ -673,6 +673,212 @@ struct ice_tlan_ctx {
> >   *      Use the enum ice_rx_l2_ptype to decode the packet type
> >   * ENDIF
> >   */
> > +#define ICE_PTYPES								\
> > +	/* L2 Packet types */							\
> > +	ICE_PTT_UNUSED_ENTRY(0),						\
> > +	ICE_PTT(1, L2, NONE, NOF, NONE, NONE, NOF, NONE, PAY2),			\
> > +	ICE_PTT_UNUSED_ENTRY(2),						\

[...]

> > + * @eop_desc: End of Packet descriptor
> > + */
> > +static enum xdp_rss_hash_type
> > +ice_xdp_rx_hash_type(union ice_32b_rx_flex_desc *eop_desc)
> > +{
> > +	u16 ptype = ice_get_ptype(eop_desc);
> > +
> > +	if (unlikely(ptype >= ICE_NUM_DEFINED_PTYPES))
> > +		return 0;
> > +
> > +	return ice_ptype_to_xdp_hash[ptype];
> > +}
> > +
> > +/**
> > + * ice_xdp_rx_hash - RX hash XDP hint handler
> > + * @ctx: XDP buff pointer
> > + * @hash: hash destination address
> > + * @rss_type: XDP hash type destination address
> > + *
> > + * Copy RX hash (if available) and its type to the destination address.
> > + */
> > +static int ice_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
> > +			   enum xdp_rss_hash_type *rss_type)
> > +{
> > +	const struct ice_xdp_buff *xdp_ext = (void *)ctx;
> > +
> > +	*rss_type = ice_xdp_rx_hash_type(xdp_ext->eop_desc);
> > +	if (!ice_copy_rx_hash_from_desc(xdp_ext->eop_desc, hash))
> > +		return -EOPNOTSUPP;
> 
> Same here? See the following for the context:
> https://lore.kernel.org/bpf/167940675120.2718408.8176058626864184420.stgit@firesoul/

Thanks! Will fix.