On Fri, Feb 18, 2022 at 7:15 PM Tiezhu Yang <yangtiezhu@xxxxxxxxxxx> wrote: > > Currently, only x86, arm64 and s390 select ARCH_WANT_DEFAULT_BPF_JIT, > the other archs do not select ARCH_WANT_DEFAULT_BPF_JIT. On the archs > without ARCH_WANT_DEFAULT_BPF_JIT, if we want to set bpf_jit_enable to > 1 by default, the only way is to enable CONFIG_BPF_JIT_ALWAYS_ON, then > the users can not change it to 0 or 2, it seems bad for some users. We > can select ARCH_WANT_DEFAULT_BPF_JIT for those archs if it is proper, > but at least for now, make BPF_JIT_DEFAULT_ON selectable can give them > a chance. > > Additionally, with this patch, under !BPF_JIT_ALWAYS_ON, we can disable > BPF_JIT_DEFAULT_ON on the archs with ARCH_WANT_DEFAULT_BPF_JIT when make > menuconfig, it seems flexible for some developers. > > Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx> > --- > kernel/bpf/Kconfig | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/kernel/bpf/Kconfig b/kernel/bpf/Kconfig > index cbf3f65..461ac60 100644 > --- a/kernel/bpf/Kconfig > +++ b/kernel/bpf/Kconfig > @@ -54,6 +54,7 @@ config BPF_JIT > config BPF_JIT_ALWAYS_ON > bool "Permanently enable BPF JIT and remove BPF interpreter" > depends on BPF_SYSCALL && HAVE_EBPF_JIT && BPF_JIT > + select BPF_JIT_DEFAULT_ON > help > Enables BPF JIT and removes BPF interpreter to avoid speculative > execution of BPF instructions by the interpreter. > @@ -63,8 +64,16 @@ config BPF_JIT_ALWAYS_ON > in failure. > > config BPF_JIT_DEFAULT_ON > - def_bool ARCH_WANT_DEFAULT_BPF_JIT || BPF_JIT_ALWAYS_ON > - depends on HAVE_EBPF_JIT && BPF_JIT > + bool "Defaultly enable BPF JIT and remove BPF interpreter" I think "remove BPF interpreter" is not accurate. I guess we can just say "Enable BPF JIT by default". (also "defaultly" sounds weird to me). > + default y if ARCH_WANT_DEFAULT_BPF_JIT > + depends on BPF_SYSCALL && HAVE_EBPF_JIT && BPF_JIT > + help > + Enables BPF JIT and removes BPF interpreter to avoid speculative > + execution of BPF instructions by the interpreter. > + > + When CONFIG_BPF_JIT_DEFAULT_ON is enabled but CONFIG_BPF_JIT_ALWAYS_ON > + is disabled, /proc/sys/net/core/bpf_jit_enable is set to 1 by default > + and can be changed to 0 or 2. > > config BPF_UNPRIV_DEFAULT_OFF > bool "Disable unprivileged BPF by default" > -- > 2.1.0 >
