> On 02/10, Lorenzo Bianconi wrote: > > > On 09/26, Jesper Dangaard Brouer wrote: > > > > > > > > > > > > On 26/09/2025 06.20, Stanislav Fomichev wrote: > > > > > On 09/25, Lorenzo Bianconi wrote: > > > > > > Introduce XDP RX checksum capability to XDP metadata specs. XDP RX > > > > > > checksum will be use by devices capable of exposing receive checksum > > > > > > result via bpf_xdp_metadata_rx_checksum(). > > > > > > Moreover, introduce xmo_rx_checksum netdev callback in order allow > > > > > > the > > > > > > eBPF program bounded to the device to retrieve the RX checksum > > > > > > result > > > > > > computed by the hw NIC. > > > > > > > > > > > > Signed-off-by: Lorenzo Bianconi <[email protected]> > > > > > > --- > > > > > > Documentation/netlink/specs/netdev.yaml | 5 +++++ > > > > > > include/net/xdp.h | 14 ++++++++++++++ > > > > > > net/core/xdp.c | 29 > > > > > > +++++++++++++++++++++++++++++ > > > > > > 3 files changed, 48 insertions(+) > > > > > > > > > > > > diff --git a/Documentation/netlink/specs/netdev.yaml > > > > > > b/Documentation/netlink/specs/netdev.yaml > > > > > > index > > > > > > e00d3fa1c152d7165e9485d6d383a2cc9cef7cfd..00699bf4a7fdb67c6b9ee3548098b0c933fd39a4 > > > > > > 100644 > > > > > > --- a/Documentation/netlink/specs/netdev.yaml > > > > > > +++ b/Documentation/netlink/specs/netdev.yaml > > > > > > @@ -61,6 +61,11 @@ definitions: > > > > > > doc: | > > > > > > Device is capable of exposing receive packet VLAN tag > > > > > > via > > > > > > bpf_xdp_metadata_rx_vlan_tag(). > > > > > > + - > > > > > > + name: checksum > > > > > > + doc: | > > > > > > + Device is capable of exposing receive checksum result via > > > > > > + bpf_xdp_metadata_rx_checksum(). > > > > > > - > > > > > > type: flags > > > > > > name: xsk-flags > > > > > > diff --git a/include/net/xdp.h b/include/net/xdp.h > > > > > > index > > > > > > aa742f413c358575396530879af4570dc3fc18de..9ab9ac10ae2074b70618a9d4f32544d8b9a30b63 > > > > > > 100644 > > > > > > --- a/include/net/xdp.h > > > > > > +++ b/include/net/xdp.h > > > > > > @@ -586,6 +586,10 @@ void xdp_attachment_setup(struct > > > > > > xdp_attachment_info *info, > > > > > > NETDEV_XDP_RX_METADATA_VLAN_TAG, \ > > > > > > bpf_xdp_metadata_rx_vlan_tag, \ > > > > > > xmo_rx_vlan_tag) \ > > > > > > + XDP_METADATA_KFUNC(XDP_METADATA_KFUNC_RX_CHECKSUM, \ > > > > > > + NETDEV_XDP_RX_METADATA_CHECKSUM, \ > > > > > > + bpf_xdp_metadata_rx_checksum, \ > > > > > > + xmo_rx_checksum) > > > > > > enum xdp_rx_metadata { > > > > > > #define XDP_METADATA_KFUNC(name, _, __, ___) name, > > > > > > @@ -643,12 +647,22 @@ enum xdp_rss_hash_type { > > > > > > XDP_RSS_TYPE_L4_IPV6_SCTP_EX = XDP_RSS_TYPE_L4_IPV6_SCTP | > > > > > > XDP_RSS_L3_DYNHDR, > > > > > > }; > > > > > > +enum xdp_checksum { > > > > > > + XDP_CHECKSUM_NONE = CHECKSUM_NONE, > > > > > > + XDP_CHECKSUM_UNNECESSARY = CHECKSUM_UNNECESSARY, > > > > > > + XDP_CHECKSUM_COMPLETE = CHECKSUM_COMPLETE, > > > > > > + XDP_CHECKSUM_PARTIAL = CHECKSUM_PARTIAL, > > > > > > +}; > > > > > > > > > > Btw, might be worth mentioning, awhile ago we had settled on a > > > > > smaller set of > > > > > exposed types: > > > > > > > > > > https://lore.kernel.org/netdev/[email protected]/ > > > > > > > > > > Maybe go through the previous postings and check if the arguments are > > > > > still relevant? (or explain why we want more checksum now) > > > > > > > > IHMO the linked proposal reduced the types too much. > > > > > > IIRC, PARTIAL was removed because it's mostly (or only) a TX feature? > > > So no real need to expose it as an rx hint. And I think empty > > > xdp_csum_status > > > in that proposal might have indicated NONE? > > > > Sorry for the (very) late reply. According to [0] CHECKSUM_PARTIAL can be > > used > > even on Rx side, right? > > So is this for virtio (which I don't think you need)? Or something else?
I forgot to mention before CHECKSUM_PARTIAL is used for the veth use-case when the packet is coming from the networking stack. > Can we start with the "easy" cases of UNNECESSARY/COMPLETE/NONE? I'm not even > sure we need to expose the csum_level (start with level=0 and handle > encap if/when there is a real usecase). With kfuncs we should be able to > change/extend the API when needed. ack, I am fine to drop csum_level for the moment but I am not sure if it can be useful for the use-case described by Jesper. @Jesper: any input on it? Regards, Lorenzo > > (for PARTIAL, not even sure what the BPF prog is supposed to do with it)
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