From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6BB37C433E0 for ; Wed, 15 Jul 2020 17:53:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 422B920663 for ; Wed, 15 Jul 2020 17:53:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="qW5AXC2Y" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725882AbgGORxE (ORCPT ); Wed, 15 Jul 2020 13:53:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725861AbgGORxD (ORCPT ); Wed, 15 Jul 2020 13:53:03 -0400 Received: from mail-lf1-x143.google.com (mail-lf1-x143.google.com [IPv6:2a00:1450:4864:20::143]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9304CC061755; Wed, 15 Jul 2020 10:53:03 -0700 (PDT) Received: by mail-lf1-x143.google.com with SMTP id g139so1543123lfd.10; Wed, 15 Jul 2020 10:53:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Kzxx9RCldh3DF2JWeX19dZw4RjKkD4KoJuSfX3PHNJQ=; b=qW5AXC2Yja3W1A52gYUqCskX1FKrCdiGVWVNMlxPUBjnPRwxvtff4mZwg1L9SpEveC Qd9WuJkImx2UkE9WoLAeC/xt90kYdvlnYqJ85anwQek1YJ+HMuh8AvJE2oOgnltweKGf X4uU8Uok/qkEv5fs9u8TvLfuzCfyXt2XGj/VMCmAuc9UuGVpH5+Dih9Bnpp19w3jZotM OonXlr/J4Nt3RxxEKTSmqbnuI6NvRcY/NVEKtt22KilDY0pzxGRnQkashBBjJ7puNLYR xM9Bb/+hNPuUFtrBVnPZlSiurBb5NxGOUvgo1U8//1obKXoZ5mZIjb2gaIQsPxvMbJrb FxOQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Kzxx9RCldh3DF2JWeX19dZw4RjKkD4KoJuSfX3PHNJQ=; b=kmVgpxXRDg6JTAKKo3Z7V8Jk7zxbStQXLql0YKqPGVN4oAgX+yJB3dxsXnRCQrQr5Y n9ZRPsBDfM+KjZIwOE4MoyQfBYivVMZHezBmWl864Q5OfnBKI4nQFe8jmToCzk7UA3Cm JCVAGg1gX/dzFDxXf+LX9rcfUGT/L1sii+FCcPjEAKPNwBUos1lMRvAomHPgjTXz5y1y JJ/s1uKKiouyzmYRFJXsC8/kn6Y8OAsEgfH8bZWbtKaIrDTlgiG99ykIHC8mitWv6K0t WP1hNXRS/t67YzUPSQYLU2tEgKMWhhkxjn9fdBag1lfmqbS3yPMJzSELf2mo1VeKyRmj xoQQ== X-Gm-Message-State: AOAM531jtRKfa3/hVUKoVCO21zUAzcGLnilV7TSKNVCsK2KQtKGAj1rw oC+Ddep/z7OCnM3k+XvhoJceAyZ7J9GwtHP+WaI= X-Google-Smtp-Source: ABdhPJxeXRyiSlooQK4CZ0BwYELn9wcNO6PMpKVr0ehAqhKnTARZVOCc3oCHuE2p+cWx+UVz2bWL8Vck7IoMJMq4LDY= X-Received: by 2002:a19:a95:: with SMTP id 143mr109682lfk.174.1594835581993; Wed, 15 Jul 2020 10:53:01 -0700 (PDT) MIME-Version: 1.0 References: <20200713161739.3076283-1-yhs@fb.com> <20200713161742.3076597-1-yhs@fb.com> <20200713232545.mmocpqgqpiapcdvg@ast-mbp.dhcp.thefacebook.com> <2b641c41-fd6e-b1fa-4043-02b92776140e@fb.com> In-Reply-To: <2b641c41-fd6e-b1fa-4043-02b92776140e@fb.com> From: Alexei Starovoitov Date: Wed, 15 Jul 2020 10:52:50 -0700 Message-ID: Subject: Re: [PATCH bpf-next 03/13] bpf: support readonly buffer in verifier To: Yonghong Song Cc: bpf , Network Development , Alexei Starovoitov , Daniel Borkmann , Kernel Team , Martin KaFai Lau Content-Type: text/plain; charset="UTF-8" Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Wed, Jul 15, 2020 at 10:48 AM Yonghong Song wrote: > > > PTR_TO_TP_BUFFER was a quick hack for tiny scratch area. > > Here I think the verifier should be smart from the start. > > > The next patch populates bpf_ctx_arg_aux with hardcoded 0 and 1. > > imo that's too hacky. Helper definitions shouldn't be in business > > of poking into such verifier internals. > > The reason I am using 0/1 so later on I can easily correlate > which rdonly_buf access size corresponds to key or value. I guess > I can have a verifier callback to given an ctx argument index to > get the access size. I see. Hardcoding key vs value in some way is necessary, of course. Some #define for that with clear name would be good. I was pointing out that 0/1 were used beyond that need.