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=-5.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_1 autolearn=no 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 45EEAC2D0A3 for ; Mon, 16 Nov 2020 20:19:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F199E21D7E for ; Mon, 16 Nov 2020 20:19:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="OaZMygvS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732327AbgKPUTX (ORCPT ); Mon, 16 Nov 2020 15:19:23 -0500 Received: from aserp2120.oracle.com ([141.146.126.78]:40480 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727849AbgKPUTW (ORCPT ); Mon, 16 Nov 2020 15:19:22 -0500 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0AGKE7FC184017; Mon, 16 Nov 2020 20:18:47 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2020-01-29; bh=BYnJRTZcs0oaUzlPY8WjSL5rSKEpZDv+xiUp4uldaUo=; b=OaZMygvS4nsU1iJVGY1OS8MDUKL4YHc3INxFzS7U9kiKGx69Plx5KRM04lnKSOD8R3MX QPH9eq9l4wOSh98GZCu1VuX/QWn4OUTASKPSPNbK1CT4ahzG8g/2TlAfR8IosGGZq7ou kabF9x/HLVIMO27Ft8T48AyDkjnxovEhngV91TeDewJLHKdbNoH2JT4nWWqCk7pwrQZF j/jJcx9kLTI/mny+MGVSxzMToBQcWF7dI0RqHelCkhhhtBkeir9VrZ/xgykM+/IJS2cq QHxjRA88gz551wYrhHT3HaUzD1SNQIO+f3RXbZnhZiMlz6MI2dXFAB9E3OY+1+4fTDgP Wg== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by aserp2120.oracle.com with ESMTP id 34t76kq3su-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 16 Nov 2020 20:18:47 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0AGKAUKS132359; Mon, 16 Nov 2020 20:18:46 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3030.oracle.com with ESMTP id 34ts5v5016-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 16 Nov 2020 20:18:46 +0000 Received: from abhmp0013.oracle.com (abhmp0013.oracle.com [141.146.116.19]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 0AGKIhNg018994; Mon, 16 Nov 2020 20:18:43 GMT Received: from localhost.localdomain (/92.157.91.83) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 16 Nov 2020 12:18:43 -0800 Subject: Re: [RFC][PATCH v2 11/21] x86/pti: Extend PTI user mappings To: Andy Lutomirski Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , X86 ML , Dave Hansen , Peter Zijlstra , LKML , Tom Lendacky , Joerg Roedel , Konrad Rzeszutek Wilk , jan.setjeeilers@oracle.com, Junaid Shahid , oweisse@google.com, Mike Rapoport , Alexander Graf , mgross@linux.intel.com, kuzuno@gmail.com References: <20201116144757.1920077-1-alexandre.chartre@oracle.com> <20201116144757.1920077-12-alexandre.chartre@oracle.com> From: Alexandre Chartre Message-ID: <820278dc-5f8e-6224-71b4-7c61819f68d1@oracle.com> Date: Mon, 16 Nov 2020 21:21:03 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9807 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 spamscore=0 phishscore=0 suspectscore=0 mlxscore=0 malwarescore=0 bulkscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011160117 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9807 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 phishscore=0 adultscore=0 priorityscore=1501 bulkscore=0 clxscore=1015 mlxlogscore=999 malwarescore=0 mlxscore=0 spamscore=0 lowpriorityscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011160117 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/16/20 8:48 PM, Andy Lutomirski wrote: > On Mon, Nov 16, 2020 at 6:49 AM Alexandre Chartre > wrote: >> >> Extend PTI user mappings so that more kernel entry code can be executed >> with the user page-table. To do so, we need to map syscall and interrupt >> entry code, per cpu offsets (__per_cpu_offset, which is used some in >> entry code), the stack canary, and the PTI stack (which is defined per >> task). > > Does anything unmap the PTI stack? Mapping is easy, and unmapping > could be a pretty big mess. > No, there's no unmap. The mapping exists as long as the task page-table does (i.e. as long as the task mm exits). I assume that the task stack and mm are freed at the same time but that's not something I have checked. alex.