Alexei Starovoitov [off-list ref] writes:

On 3/26/21 3:11 AM, Toke Høiland-Jørgensen wrote:

quoted

Martin KaFai Lau [off-list ref] writes:

quoted

On Thu, Mar 25, 2021 at 11:02:23PM +0100, Toke Høiland-Jørgensen wrote:

quoted

Martin KaFai Lau [off-list ref] writes:

quoted

This patch adds support to BPF verifier to allow bpf program calling
kernel function directly.

Hi Martin

This is exciting stuff! :)

Just one quick question about this:

quoted

[ For the future calling function-in-kernel-module support, an array
   of module btf_fds can be passed at the load time and insn->off
   can be used to index into this array. ]

Is adding the support for extending this to modules also on your radar,
or is this more of an "in case someone needs it" comment? :)

It is in my list.  I don't mind someone beats me to it though
if he/she has an immediate use case. ;)

Noted ;)
No promises though, and at the rate you're going you may just get there
first. I'll be sure to ping you if I do start on this so we avoid
duplicating effort!

That's great!
Curious what use cases you have in mind?

Accessing conntrack data from XDP. Needed for OVS, and for building an
XDP-based forwarding fast-path that shares state with the regular kernel
stack. Details TBD, obviously, but we've been blocked on not having
access to anything in modules from BPF, so seeing that there's now a
path to that is delightful! :)

-Toke