Re: [PATCH bpf-next 0/2] Clarify and Enhance XDP Rx Metadata Handling

[Jakub Kicinski]

On Tue,  1 Jul 2025 12:29:38 +0800 Song Yoong Siang wrote:
>                         |<---sizeof(xdp_meta)--|
>                         |                      |
>                  struct xdp_meta               rx_desc->address
>                         ^                      ^
>                         |                      |
> +----------+----------------------+------------+------+
> | headroom |    custom metadata   |  reserved  | data |
> +----------+----------------------+------------+------+
>            ^                      ^            ^
>            |                      |            |
>     struct xdp_meta     xdp_buff->data_meta    xdp_buff->data
>            |                      |
>            |<---sizeof(xdp_meta)--|

Huh. Did AF_XDP maintainers explicitly sign off on this or it's just how
IGC implementation works and nobody noticed?

For normal XDP my understanding is that its the driver's responsibility
to move the "reserved" stuff out of place before presenting the frame to
program.