On Thu, 10 Jul 2025 15:35:32 +0000 Song, Yoong Siang wrote: > Would it be advisable to update the documentation to indicate that > drivers are expected to copy any device-reserved metadata from the > metadata area? This would ensure that xdp_buff->data_meta is equal > to xdp_buff->data before a BPF program is executed. This approach > would allow BPF programs to freely manipulate the metadata area > in XDP_REDIRECT scenarios. Documenting sounds good. > Additionally, I am uncertain about the need to overriding metadata in > XDP_PASS scenarios. Should BPF programs refrain from overriding the > metadata in this case? IIRC XDP_PASS was the initial use case for the metadata area. The driver needs to evacuate any HW metadata before handing over to the XDP program.
