Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Feedback-ID: id4a34324:Fastmail
Date:   Sat, 2 Jul 2022 20:14:56 -0700
From:   Andres Freund <andres@anarazel.de>
To:     Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc:     Song Liu <song@kernel.org>, bpf <bpf@vger.kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Kernel Team <kernel-team@fb.com>,
        Peter Zijlstra <peterz@infradead.org>, X86 ML <x86@kernel.org>,
        Ilya Leoshkevich <iii@linux.ibm.com>,
        Song Liu <songliubraving@fb.com>
Subject: Re: [PATCH v9 bpf-next 9/9] bpf, x86_64: use
 bpf_jit_binary_pack_alloc
Message-ID: <20220703031456.rsj4ruqmcr34mnsd@alap3.anarazel.de>
References: <20220204185742.271030-1-song@kernel.org>
 <20220204185742.271030-10-song@kernel.org>
 <20220703030210.pmjft7qc2eajzi6c@alap3.anarazel.de>
 <CAADnVQJmHTTri-s7dvFbLCXKZsZXopnVNFCpkmeHPYg2h6LkZg@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAADnVQJmHTTri-s7dvFbLCXKZsZXopnVNFCpkmeHPYg2h6LkZg@mail.gmail.com>
Precedence: bulk

Hi,

On 2022-07-02 20:03:56 -0700, Alexei Starovoitov wrote:
> On Sat, Jul 2, 2022 at 8:02 PM Andres Freund <andres@anarazel.de> wrote:
> > On 2022-02-04 10:57:42 -0800, Song Liu wrote:
> > > From: Song Liu <songliubraving@fb.com>
> > >
> > > Use bpf_jit_binary_pack_alloc in x86_64 jit. The jit engine first writes
> > > the program to the rw buffer. When the jit is done, the program is copied
> > > to the final location with bpf_jit_binary_pack_finalize.
> > >
> > > Note that we need to do bpf_tail_call_direct_fixup after finalize.
> > > Therefore, the text_live = false logic in __bpf_arch_text_poke is no
> > > longer needed.
> >
> > I think this broke bpf_jit_enable = 2.
> 
> Good. We need to remove that knob.
> It's been wrong for a long time.

Fine with me - I've never used it before trying to verify I am not breaking
tools/bpf/bpf_jit_disasm...

And yea, it does look like it bpf_jit_dump() was called too early before that
commit as well, just not as consequentially so.

Greetings,

Andres Freund