[$] Binary portability for BPF programs

The BPF virtual machine is the same on all architectures where it is
supported; architecture-specific code takes care of translating BPF to
something the local processor can understand. So one might be tempted to
think that BPF programs would be portable across architectures but, in many
cases, that turns out not to be true. During the BPF microconference at the
Linux Plumbers
Conference, Alexei Starovoitov (assisted by Yonghong Song, who has done
much of the work described) explained
the problem and the work that has
been done toward 'compile once, run everywhere' BPF.