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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 28992C31E57 for ; Mon, 17 Jun 2019 11:01:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E5C14208C0 for ; Mon, 17 Jun 2019 11:01:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727820AbfFQLBo (ORCPT ); Mon, 17 Jun 2019 07:01:44 -0400 Received: from mga04.intel.com ([192.55.52.120]:11211 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727376AbfFQLBo (ORCPT ); Mon, 17 Jun 2019 07:01:44 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Jun 2019 04:01:43 -0700 X-ExtLoop1: 1 Received: from khuang2-desk.gar.corp.intel.com ([10.255.91.82]) by fmsmga006.fm.intel.com with ESMTP; 17 Jun 2019 04:01:39 -0700 Message-ID: <1560769298.5187.16.camel@linux.intel.com> Subject: Re: [PATCH, RFC 20/62] mm/page_ext: Export lookup_page_ext() symbol From: Kai Huang To: Peter Zijlstra , "Kirill A. Shutemov" Cc: "Kirill A. Shutemov" , Andrew Morton , x86@kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Borislav Petkov , Andy Lutomirski , David Howells , Kees Cook , Dave Hansen , Jacob Pan , Alison Schofield , linux-mm@kvack.org, kvm@vger.kernel.org, keyrings@vger.kernel.org, linux-kernel@vger.kernel.org Date: Mon, 17 Jun 2019 23:01:38 +1200 In-Reply-To: <20190617093054.GB3419@hirez.programming.kicks-ass.net> References: <20190508144422.13171-1-kirill.shutemov@linux.intel.com> <20190508144422.13171-21-kirill.shutemov@linux.intel.com> <20190614111259.GA3436@hirez.programming.kicks-ass.net> <20190614224443.qmqolaigu5wnf75p@box> <20190617093054.GB3419@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.24.6 (3.24.6-1.fc26) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2019-06-17 at 11:30 +0200, Peter Zijlstra wrote: > On Sat, Jun 15, 2019 at 01:44:43AM +0300, Kirill A. Shutemov wrote: > > On Fri, Jun 14, 2019 at 01:12:59PM +0200, Peter Zijlstra wrote: > > > On Wed, May 08, 2019 at 05:43:40PM +0300, Kirill A. Shutemov wrote: > > > > page_keyid() is inline funcation that uses lookup_page_ext(). KVM is > > > > going to use page_keyid() and since KVM can be built as a module > > > > lookup_page_ext() has to be exported. > > > > > > I _really_ hate having to export world+dog for KVM. This one might not > > > be a real issue, but I itch every time I see an export for KVM these > > > days. > > > > Is there any better way? Do we need to invent EXPORT_SYMBOL_KVM()? :P > > Or disallow KVM (or parts thereof) from being a module anymore. For this particular symbol expose, I don't think its fair to blame KVM since the fundamental reason is because page_keyid() (which calls lookup_page_ext()) being implemented as static inline function in header file, so essentially having any other module who calls page_keyid() will trigger this problem -- in fact IOMMU driver calls page_keyid() too so even w/o KVM lookup_page_ext() needs to be exposed. Thanks, -Kai