Re: [PATCH] bpf: validate bpf_func when BPF_JIT is enabled

From: Sami Tolvanen
Date: Wed Sep 11 2019 - 17:07:57 EST

On Wed, Sep 11, 2019 at 5:09 AM Toke HÃiland-JÃrgensen <toke@xxxxxxxxxx> wrote:
> BjÃrn TÃpel <bjorn.topel@xxxxxxxxx> writes:
> > I ran the "xdp_rxq_info" sample with and without Sami's patch:
> Thanks for doing this!

Yes, thanks for testing this BjÃrn!

> Or (1/22998700 - 1/23923874) * 10**9 == 1.7 nanoseconds of overhead.
> I guess that is not *too* bad; but it's still chipping away at
> performance; anything we could do to lower the overhead?

The check is already rather minimal, but I could move this to a static
inline function to help ensure the compiler doesn't generate an
additional function call for this. I'm also fine with gating this
behind a separate config option, but I'm not sure if that's worth it.
Any thoughts?