On Thu, 2025-03-13 at 18:21 +0100, Luis Gerhorst wrote:
This is required to catch the errors later and fall back to a nospec if on a speculative path.
Move code into do_check_insn(), replace
- "continue" with "return INSN_IDX_MODIFIED"
- "goto process_bpf_exit" with "return PROCESS_BPF_EXIT"
- "do_print_state = " with "*do_print_state = "
Signed-off-by: Luis Gerhorst luis.gerhorst@fau.de Acked-by: Henriette Herzog henriette.herzog@rub.de Cc: Maximilian Ott ott@cs.fau.de Cc: Milan Stephan milan.stephan@fau.de
This refactoring is a long overdue, thank you! A few nits below.
[...]
err = do_check_insn(env, insn, pop_log, &do_print_state, regs, state,&prev_insn_idx);
- `regs` remains declared in do_check(), while nothing prevents pushing its declaration to do_check_insn(). - `state` is `env->cur_state`, so I'd avoid passing it as a parameter (just to reduce count); - `prev_insn_idx` is unused by `do_check_insn`; - `pop_log` is not used by `do_check_insn`; - given that `insn` is presumed to correspond to `env->insn_idx` in many places down the stack not sure about this parameter.
if (err < 0) {return err;} else if (err == INSN_IDX_MODIFIED) {
Also, I'd get rid of `INSN_IDX_MODIFIED` and move `env->insn_idx++` into `do_check_insn()`. This would save a few mental cycles when looking at the code with full patch-set applied:
} else if (err == INSN_IDX_MODIFIED) { continue; } else if (err == PROCESS_BPF_EXIT) { goto process_bpf_exit; } WARN_ON_ONCE(err);
if (state->speculative && cur_aux(env)->nospec_result) { ... bunch of actions ... }
env->insn_idx++;
One needs to stop for a moment and think why "bunch of actions" is performed for regular index increment, but not for INSN_IDX_MODIFIED.
continue;} else if (err == PROCESS_BPF_EXIT) {
[...]