[PATCH bpf-next 0/2] BPF kselftest cross-build/RISC-V fixes

[Björn Töpel]

Daniel Borkmann <daniel at iogearbox.net> writes:

> On 7/5/23 1:39 PM, Björn Töpel wrote:
>> From: Björn Töpel <bjorn at rivosinc.com>
>> 
>> This series has two minor fixes, found when cross-compiling for the
>> RISC-V architecture.
>> 
>> Some RISC-V systems do not define HAVE_EFFICIENT_UNALIGNED_ACCESS,
>> which made some of tests bail out. Fix the failing tests by adding
>> F_NEEDS_EFFICIENT_UNALIGNED_ACCESS.
>> 
>> ...and some RISC-V systems *do* define
>> HAVE_EFFICIENT_UNALIGNED_ACCESS. In this case the autoconf.h was not
>> correctly picked up by the build system.
>
> Looks good, applied thanks! 

Thank you!

> Any plans on working towards integrating riscv into upstream BPF CI?
> Would love to see that happening. :)

Yes! I started hacking a bit on that some time back:

  https://github.com/libbpf/ci/pull/87
  https://github.com/kernel-patches/vmtest/pull/194

(TL;DR: I'll continuing that work at some point.)

RISC-V still needs cross-compilation, and testing on qemu/TCG (on
typically x86-hosts), which puts some constraints on the
rootfs/cross-compilation host; For RISC-V Debian Bullseye is way too old
(a lot packages are missing/broken). Typically for BPF it would be
Ubuntu Kinetic (or later), or some Debian Sid snapshot.

The rootfs, the host, and the host foreign arch would need to be the
same for "no-hassle cross-compilation on Debian derivatives" -- and at
least younger than "Ubuntu Kinetic"-age.

AFAIU, there are some issues with rootfs version and build host
versioning for other archs as well: https://github.com/libbpf/ci/pull/83


Björn