Re: [PATCH bpf-next v2 1/2] bpf: Add some description about BPF_JIT_ALWAYS_ON in Kconfig

[Song Liu]

On Fri, Feb 18, 2022 at 7:15 PM Tiezhu Yang <yangtiezhu@xxxxxxxxxxx> wrote:
>
> When CONFIG_BPF_JIT_ALWAYS_ON is enabled, /proc/sys/net/core/bpf_jit_enable
> is permanently set to 1 and setting any other value than that will return
> in failure.
>
> Add the above description in the help text of config BPF_JIT_ALWAYS_ON, and
> then we can distinguish between BPF_JIT_ALWAYS_ON and BPF_JIT_DEFAULT_ON.
>
> Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
> ---
>  kernel/bpf/Kconfig | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/kernel/bpf/Kconfig b/kernel/bpf/Kconfig
> index d24d518..cbf3f65 100644
> --- a/kernel/bpf/Kconfig
> +++ b/kernel/bpf/Kconfig
> @@ -58,6 +58,10 @@ config BPF_JIT_ALWAYS_ON
>           Enables BPF JIT and removes BPF interpreter to avoid speculative
>           execution of BPF instructions by the interpreter.
>
> +         When CONFIG_BPF_JIT_ALWAYS_ON is enabled, /proc/sys/net/core/bpf_jit_enable
> +         is permanently set to 1 and setting any other value than that will return
> +         in failure.

nit: "return failure" (no "in").

Other than this,

Acked-by: Song Liu <songliubraving@xxxxxx>

> +
>  config BPF_JIT_DEFAULT_ON
>         def_bool ARCH_WANT_DEFAULT_BPF_JIT || BPF_JIT_ALWAYS_ON
>         depends on HAVE_EBPF_JIT && BPF_JIT
> --
> 2.1.0
>