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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7D61C433F5 for ; Fri, 13 May 2022 23:22:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 54C586B0073; Fri, 13 May 2022 19:22:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4FAE46B0075; Fri, 13 May 2022 19:22:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 39AEA6B0078; Fri, 13 May 2022 19:22:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 287EB6B0073 for ; Fri, 13 May 2022 19:22:49 -0400 (EDT) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id D1C1B32C1F for ; Fri, 13 May 2022 23:22:48 +0000 (UTC) X-FDA: 79462296816.14.BE26A19 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by imf05.hostedemail.com (Postfix) with ESMTP id 2FB37100009 for ; Fri, 13 May 2022 23:22:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1652484168; x=1684020168; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=KyCPdSxq6CFmcl2pjIuOEIvI0ilyCrZM3eYSgEPizRA=; b=glHUH6N7dK6I2+YFL0H0th2jSMASnrmlkSWCm1P5RWlY+XPHGDOI3Hpp HzhcST71f+xNwNsVOCMfy1c+An0I4Mn4cXXtY1Qf7OTjdEf9tGiWIP2o7 KZwviDCGxZS5ygN51pwrmYGurnpIB10hEhkRY6N5EZSw6La4HgqtH+D6h pGAA23+H5Ef/4f5tUDU/IlF//cm+SsLtlru9+mIWvelD89Yzd7PksN5h7 ZlLUFIysGadV2WeyeBNADVVTQO67iZC/wzQXgxOyTwxgK+4RBh/tNghRq 2gr0AUyUPW5a3RjfIIbWp3whs/SGJjgPxv1HgJHiCUPavzYGEcPQ9v2/o Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10346"; a="270105568" X-IronPort-AV: E=Sophos;i="5.91,223,1647327600"; d="scan'208";a="270105568" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 May 2022 16:22:47 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.91,223,1647327600"; d="scan'208";a="815595889" Received: from black.fi.intel.com ([10.237.72.28]) by fmsmga006.fm.intel.com with ESMTP; 13 May 2022 16:22:43 -0700 Received: by black.fi.intel.com (Postfix, from userid 1000) id EBD60A8; Sat, 14 May 2022 02:22:42 +0300 (EEST) Date: Sat, 14 May 2022 02:22:42 +0300 From: "Kirill A. Shutemov" To: Thomas Gleixner Cc: Dave Hansen , Andy Lutomirski , Peter Zijlstra , x86@kernel.org, Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , "H . J . Lu" , Andi Kleen , Rick Edgecombe , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFCv2 08/10] x86/mm: Make LAM_U48 and mappings above 47-bits mutually exclusive Message-ID: <20220513232242.7ac7herw7iyfkd2h@black.fi.intel.com> References: <20220511022751.65540-1-kirill.shutemov@linux.intel.com> <20220511022751.65540-10-kirill.shutemov@linux.intel.com> <875ymax480.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <875ymax480.ffs@tglx> X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 2FB37100009 X-Stat-Signature: c7zskrrpj75sxwpg1di1unz3a9ohhrfn X-Rspam-User: Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=glHUH6N7; spf=none (imf05.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 134.134.136.24) smtp.mailfrom=kirill.shutemov@linux.intel.com; dmarc=pass (policy=none) header.from=intel.com X-HE-Tag: 1652484147-33167 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, May 12, 2022 at 03:36:31PM +0200, Thomas Gleixner wrote: > On Wed, May 11 2022 at 05:27, Kirill A. Shutemov wrote: > > LAM_U48 steals bits above 47-bit for tags and makes it impossible for > > userspace to use full address space on 5-level paging machine. > > > Make these features mutually exclusive: whichever gets enabled first > > blocks the othe one. > > So this patch prevents a mapping above 47bit when LAM48 is enabled, but > I fail to spot how an already existing mapping above 47bit would prevent > LAM48 from being enabled. > > Maybe I'm missing something which makes this magically mutually > exclusive. It is in 09/10. See lam_u48_allowed() -- Kirill A. Shutemov