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From: Daniel Borkmann <daniel@iogearbox.net>
To: "Luke Nelson" <lukenels@cs.washington.edu>,
	"Björn Töpel" <bjorn.topel@gmail.com>
Cc: Netdev <netdev@vger.kernel.org>,
	linux-riscv@lists.infradead.org, bpf <bpf@vger.kernel.org>,
	Alexei Starovoitov <ast@kernel.org>, Xi Wang <xi.wang@gmail.com>
Subject: Re: [PATCH bpf-next 2/8] riscv, bpf: add support for far branching
Date: Mon, 9 Dec 2019 22:27:27 +0100	[thread overview]
Message-ID: <2d5d1f2d-d4ab-2449-37c6-e5b319a778d6@iogearbox.net> (raw)
In-Reply-To: <CADasFoDOyJA0nDVCyA6EY78dHSSxxV+EXS=xUyLDW4_VhJvBkQ@mail.gmail.com>

On 12/9/19 10:08 PM, Luke Nelson wrote:
[...]
> We have been developing a formal verification tool for BPF JIT
> compilers, which we have used in the past to find bugs in the RV64
> and x32 BPF JITs:
> 
> https://unsat.cs.washington.edu/projects/serval/
> 
> Recently I added support for verifying the JIT for branch and jump
> instructions, and thought it a good opportunity to verify these
> patches that add support for far jumps and branching.
> 
> I ported these patches to our tool and ran verification, which
> didn't find any bugs according to our specification of BPF and
> RISC-V.
> 
> The tool and code are publicly available, and you can read a more
> detailed writeup of the results here:
> 
> https://github.com/uw-unsat/bpf-jit-verif/tree/far-jump-review
> 
> Currently the tool works on a manually translated version of the
> JIT from C to Rosette, but we are experimenting with ways of making
> this process more automated.

This is awesome work! Did you also check for other architectures aside
from riscv and x86-32, e.g. x86-64 or arm64?

It would be great if we could add such verification tool under tools/bpf/
which would then take the in-tree JIT-code as-is for its analysis and
potentially even trigger a run out of BPF selftests. Any thoughts whether
such path would be feasible wrt serval?

> Reviewed-by: Luke Nelson <lukenels@cs.washington.edu>
> Cc: Xi Wang <xi.wang@gmail.com>

Thanks,
Daniel


  reply	other threads:[~2019-12-09 21:27 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-09 17:31 [PATCH bpf-next 0/8] riscv: BPF JIT fix, optimizations and far jumps support Björn Töpel
2019-12-09 17:31 ` [PATCH bpf-next 1/8] riscv, bpf: fix broken BPF tail calls Björn Töpel
2019-12-09 17:31 ` [PATCH bpf-next 2/8] riscv, bpf: add support for far branching Björn Töpel
2019-12-09 21:08   ` Luke Nelson
2019-12-09 21:27     ` Daniel Borkmann [this message]
2019-12-10  7:02       ` Luke Nelson
2019-12-10  5:32     ` Björn Töpel
2019-12-10  5:31   ` Björn Töpel
2019-12-09 17:31 ` [PATCH bpf-next 3/8] riscv, bpf: add support for far jumps and exits Björn Töpel
2019-12-09 21:15   ` Luke Nelson
2019-12-09 17:31 ` [PATCH bpf-next 4/8] riscv, bpf: optimize BPF tail calls Björn Töpel
2019-12-09 17:31 ` [PATCH bpf-next 5/8] riscv, bpf: provide RISC-V specific JIT image alloc/free Björn Töpel
2019-12-09 17:31 ` [PATCH bpf-next 6/8] riscv, bpf: optimize calls Björn Töpel
2019-12-09 17:31 ` [PATCH bpf-next 7/8] riscv, bpf: add missing uapi header for BPF_PROG_TYPE_PERF_EVENT programs Björn Töpel
2019-12-09 17:31 ` [PATCH bpf-next 8/8] riscv, perf: add arch specific perf_arch_bpf_user_pt_regs Björn Töpel
2019-12-19 21:59 ` [PATCH bpf-next 1/8] riscv, bpf: fix broken BPF tail calls Palmer Dabbelt

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