The default cpu version is changed from v1 to v3 in llvm version 20. See [1] for more detailed reasoning. Update bpf_devel_QA.rst so developers can find such information easily. [1] https://github.com/llvm/llvm-project/pull/107008 Signed-off-by: Yonghong Song <yonghong.song@xxxxxxxxx> --- Documentation/bpf/bpf_devel_QA.rst | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) NOTE: Timo Beckers from cilium made suggestion at https://github.com/cilium/ebpf/pull/1800#issuecomment-2959458764 diff --git a/Documentation/bpf/bpf_devel_QA.rst b/Documentation/bpf/bpf_devel_QA.rst index 0acb4c9b8d90..45bc5c5cd793 100644 --- a/Documentation/bpf/bpf_devel_QA.rst +++ b/Documentation/bpf/bpf_devel_QA.rst @@ -611,9 +611,10 @@ Q: I have added a new BPF instruction to the kernel, how can I integrate it into LLVM? A: LLVM has a ``-mcpu`` selector for the BPF back end in order to allow -the selection of BPF instruction set extensions. By default the -``generic`` processor target is used, which is the base instruction set -(v1) of BPF. +the selection of BPF instruction set extensions. Before llvm version 20, +the ``generic`` processor target is used, which is the base instruction +set (v1) of BPF. Since llvm 20, the default processor target has changed +to instruction set v3. LLVM has an option to select ``-mcpu=probe`` where it will probe the host kernel for supported BPF instruction set extensions and selects the -- 2.47.1
