From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-x442.google.com ([2607:f8b0:4864:20::442]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iPLh9-0008Cl-Vg for linux-um@lists.infradead.org; Tue, 29 Oct 2019 07:13:37 +0000 Received: by mail-pf1-x442.google.com with SMTP id c13so8891732pfp.5 for ; Tue, 29 Oct 2019 00:13:35 -0700 (PDT) Date: Tue, 29 Oct 2019 16:13:28 +0900 Message-ID: From: Hajime Tazaki Subject: Re: [RFC PATCH 03/47] lkl: architecture skeleton for Linux kernel library In-Reply-To: References: <0b1464dd4904ee2b049fef624895ead3fe6aa555.1571798507.git.thehajime@gmail.com> MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: jiangshanlai@gmail.com Cc: levex@linux.com, mattator@gmail.com, cem@freebsd.org, richard.weinberger@gmail.com, staal1978@gmail.com, motomuman@gmail.com, linux-um@lists.infradead.org, retrage01@gmail.com, petrosagg@gmail.com, tavi.purdila@gmail.com, xiaoj@google.com, mark@stillwell.me, edisonmcastro@hotmail.com, pscollins@google.com, phh@phh.me, sigmaepsilon92@gmail.com, luca.dariz@gmail.com, liuyuan@google.com Hello Lai, On Tue, 29 Oct 2019 13:04:59 +0900, Lai Jiangshan wrote: > > Hello, Hajime > > I can't get how UML&LKL is going to unify even I read > the cover-letter of the patchset. After quick glance, what I > understand is that the patchset just puts LKL under > arch/um/lkl rather than arch/lkl. It is still separated "arch" for me. > > Could you put me in more detail of the plan to unify them please? Thanks for the comment. You're right: current patchset only share Makefile(s) between UML and LKL. This is the first step toward the unification in my plan, described in the milestone of the cover letter (copy-pasted below). > Milestone > ========= > (snip) > 1. Put LKL code under arch/um (arch/um/lkl), and build it in a > separate way from UML. > 2. Share common parts of implementation between UML and LKL. > 3. Reimplement UML features with LKL API (if we wish) For the step 2, [PATCH 46/47] and [47/47] are the kind of examples for this level of unification (sorry for the very dirty code). For the step 3, I don't have any WIP code nor detailed plan. Implementing ptrace-based (or similar) syscall interception would be one of the development (I believe there are more). Offering UML feature-sets, keeping compatibility, while benefiting from LKL (e.g., various underlying environment support) would be very high-level goal since there are many users of UML (various test tool projects, including coming Kunit). Having similar archs in Linux kernel is not likely to happen; that was feedback after RFC email of LKL (in 2015). This motivates us to upstream the LKL code into arch/um. -- Hajime _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um