On Tue, Oct 4, 2022 at 5:59 PM Jakub Kicinski <kuba@xxxxxxxxxx> wrote: > > On Tue, 4 Oct 2022 17:25:51 -0700 Martin KaFai Lau wrote: > > A intentionally wild question, what does it take for the driver to return the > > hints. Is the rx_desc and rx_queue enough? When the xdp prog is calling a > > kfunc/bpf-helper, like 'hwtstamp = bpf_xdp_get_hwtstamp()', can the driver > > replace it with some inline bpf code (like how the inline code is generated for > > the map_lookup helper). The xdp prog can then store the hwstamp in the meta > > area in any layout it wants. > > Since you mentioned it... FWIW that was always my preference rather than > the BTF magic :) The jited image would have to be per-driver like we > do for BPF offload but that's easy to do from the technical > perspective (I doubt many deployments bind the same prog to multiple > HW devices).. +1, sounds like a good alternative (got your reply while typing) I'm not too versed in the rx_desc/rx_queue area, but seems like worst case that bpf_xdp_get_hwtstamp can probably receive a xdp_md ctx and parse it out from the pre-populated metadata? Btw, do we also need to think about the redirect case? What happens when I redirect one frame from a device A with one metadata format to a device B with another?
