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 513E36B03A1 for ; Mon, 10 Jul 2017 02:06:02 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id d62so104544627pfb.13 for ; Sun, 09 Jul 2017 23:06:02 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com. [148.163.156.1]) by mx.google.com with ESMTPS id t1si7255491pfj.130.2017.07.09.23.06.01 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 09 Jul 2017 23:06:01 -0700 (PDT) Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v6A6447q002654 for ; Mon, 10 Jul 2017 02:06:01 -0400 Received: from e15.ny.us.ibm.com (e15.ny.us.ibm.com [129.33.205.205]) by mx0a-001b2d01.pphosted.com with ESMTP id 2bjuj10bte-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 10 Jul 2017 02:06:00 -0400 Received: from localhost by e15.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 10 Jul 2017 02:05:59 -0400 Date: Sun, 9 Jul 2017 23:05:44 -0700 From: Ram Pai Subject: Re: [RFC v5 00/38] powerpc: Memory Protection Keys Reply-To: Ram Pai References: <1499289735-14220-1-git-send-email-linuxram@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Message-Id: <20170710060544.GF5713@ram.oc3035372033.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Anshuman Khandual Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com, dave.hansen@intel.com, hbabu@us.ibm.com, arnd@arndb.de, akpm@linux-foundation.org, corbet@lwn.net, mingo@redhat.com On Mon, Jul 10, 2017 at 11:13:23AM +0530, Anshuman Khandual wrote: > On 07/06/2017 02:51 AM, Ram Pai wrote: > > Memory protection keys enable applications to protect its > > address space from inadvertent access or corruption from > > itself. > > > > The overall idea: > > > > A process allocates a key and associates it with > > an address range within its address space. > > The process then can dynamically set read/write > > permissions on the key without involving the > > kernel. Any code that violates the permissions > > of the address space; as defined by its associated > > key, will receive a segmentation fault. > > > > This patch series enables the feature on PPC64 HPTE > > platform. > > > > ISA3.0 section 5.7.13 describes the detailed specifications. > > > > > > Testing: > > This patch series has passed all the protection key > > tests available in the selftests directory. > > The tests are updated to work on both x86 and powerpc. > > > > version v5: > > (1) reverted back to the old design -- store the > > key in the pte, instead of bypassing it. > > The v4 design slowed down the hash page path. > > (2) detects key violation when kernel is told to > > access user pages. > > (3) further refined the patches into smaller consumable > > units > > (4) page faults handlers captures the faulting key > > from the pte instead of the vma. This closes a > > race between where the key update in the vma and > > a key fault caused cause by the key programmed > > in the pte. > > (5) a key created with access-denied should > > also set it up to deny write. Fixed it. > > (6) protection-key number is displayed in smaps > > the x86 way. > > Hello Ram, > > This patch series has now grown a lot. Do you have this > hosted some where for us to pull and test it out ? BTW https://github.com/rampai/memorykeys.git branch memkey.v5.3 > do you have data points to show the difference in > performance between this version and the last one where > we skipped the bits from PTE and directly programmed the > HPTE entries looking into VMA bits. No. I dont. I am hoping you can help me out with this. RP -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org