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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1309BC4332F for ; Wed, 5 Oct 2022 11:34:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230106AbiJELey (ORCPT ); Wed, 5 Oct 2022 07:34:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35596 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229997AbiJELeS (ORCPT ); Wed, 5 Oct 2022 07:34:18 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 45BA8760EC; Wed, 5 Oct 2022 04:33:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=IfD4r/Qnubl/ZXrWJ/hqbcL8YwiA7Xmp7ErQUUoOr/8=; b=gsBoeSTnoX+6nNnHosNB3RX2Wm 2KEAZ9IKZ6OFskIwRx4wlx1XDS5f6QKQwxVbR7IEnPXs8WAqjkYjcUmjmD7DHrI27myjjTcWSR4L0 EQAO5RE/1ivJ/IS+G684FlDnjJeT7th1V7fEqLtmbqJYWRPwOFtMKBPaRoHUhXV4kgQAlq/yriK+4 UJsZvNlFIXt9nSU6fX9RzUOYWIqlF67OhnS4+fd+dfHaR0cwVwcRhMSrnb0Db1/ODuryYNf7oxY0a lUkfz/Efv4zbhc47OmDtOlhzmhj6SttDkG3sf6YcYKhp96HsB/gw3aAUP0iQ00IPapI3xFEkiwYIK NLOHHI1A==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1og2eB-000K0k-A8; Wed, 05 Oct 2022 11:33:07 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id AA0493004A1; Wed, 5 Oct 2022 13:33:02 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 90FCA29982FC3; Wed, 5 Oct 2022 13:33:02 +0200 (CEST) Date: Wed, 5 Oct 2022 13:33:02 +0200 From: Peter Zijlstra To: Rick Edgecombe Cc: x86@kernel.org, "H . Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H . J . Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Randy Dunlap , "Ravi V . Shankar" , Weijiang Yang , "Kirill A . Shutemov" , joao.moreira@intel.com, John Allen , kcc@google.com, eranian@google.com, rppt@kernel.org, jamorris@linux.microsoft.com, dethoma@microsoft.com, Yu-cheng Yu Subject: Re: [PATCH v2 10/39] x86/mm: Introduce _PAGE_COW Message-ID: References: <20220929222936.14584-1-rick.p.edgecombe@intel.com> <20220929222936.14584-11-rick.p.edgecombe@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220929222936.14584-11-rick.p.edgecombe@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 29, 2022 at 03:29:07PM -0700, Rick Edgecombe wrote: Mucho confusion here: > (a) (Write=0,Cow=1,Dirty=0) A modified, copy-on-write (COW) page. > (b) (Write=0,Cow=1,Dirty=0) A R/O page that has been COW'ed. The user page > (d) (Write=0,Cow=1,Dirty=0) A shared shadow stack PTE. When a shadow stack are all identical cases; > (c) (Write=0,Cow=0,Dirty=1) A shadow stack PTE. > (e) (Write=0,Cow=0,Dirty=1) A Cow PTE created when a processor without as are these.