Re: [PATCH bpf-next 2/3] selftests/bpf: Enable private stack tests for riscv64

[Chen Pei <cp0613@linux.alibaba.com>]

This one I am not taking: what gates the test is large stack support, a
JIT capability separate from the private stack this series adds.

> [Severity: Medium]
> Was the private_stack_two_frames test in verifier_large_stack.c missed
> in this patch?

> Since the RV64 JIT now supports the private stack, should __arch_riscv64
> be added to this test as well so that the riscv64 architecture receives
> this large stack test coverage?

The test builds a 2048 byte frame. Above MAX_BPF_STACK that is only
accepted when bpf_prog_stack_limit() returns MAX_BPF_STACK_JIT, which
requires bpf_jit_supports_large_stack() in the JIT as well as
bpf_jit_supports_subprog_tailcalls(); the former exists only for x86-64
and arm64. riscv64 rejects the program on the depth with or without a
private stack, which is why it skips behind
is_large_stack_supported(). Adding __arch_riscv64 would turn that skip
into a failure.

The other comments on this set are valid and are taken in v2.

Best regards,
Chen