From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id C9A856B000D for ; Wed, 14 Mar 2018 14:59:33 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id e10so2015714pff.3 for ; Wed, 14 Mar 2018 11:59:33 -0700 (PDT) Received: from mga11.intel.com (mga11.intel.com. [192.55.52.93]) by mx.google.com with ESMTPS id d8si2269446pgt.246.2018.03.14.11.59.32 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 14 Mar 2018 11:59:32 -0700 (PDT) Subject: Re: [PATCH 1/1 v2] x86: pkey-mprotect must allow pkey-0 References: <1521013574-27041-1-git-send-email-linuxram@us.ibm.com> <18b155e3-07e9-5a4b-1f95-e1667078438c@intel.com> <20180314171448.GA1060@ram.oc3035372033.ibm.com> <5027ca9e-63c8-47ab-960d-a9c4466d7075@intel.com> <20180314185452.GB1060@ram.oc3035372033.ibm.com> From: Dave Hansen Message-ID: <3f7c9ee7-46db-723f-177d-7505d0ac1e41@intel.com> Date: Wed, 14 Mar 2018 11:58:29 -0700 MIME-Version: 1.0 In-Reply-To: <20180314185452.GB1060@ram.oc3035372033.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Ram Pai Cc: mingo@redhat.com, mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, x86@kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, benh@kernel.crashing.org, paulus@samba.org, khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com, hbabu@us.ibm.com, mhocko@kernel.org, bauerman@linux.vnet.ibm.com, ebiederm@xmission.com, corbet@lwn.net, arnd@arndb.de, fweimer@redhat.com, msuchanek@suse.com On 03/14/2018 11:54 AM, Ram Pai wrote: >>> (e) it bypasses key-permission checks when assigned. >> I don't think this is necessary. I think the only rule we *need* is: >> >> pkey-0 is allocated implicitly at execve() time. You do not >> need to call pkey_alloc() to allocate it. > And can be explicitly associated with any address range ? Yes, it should ideally be available for use just like any other key when allocated.