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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 488E3C433E0 for ; Mon, 15 Jun 2020 14:53:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 274922078A for ; Mon, 15 Jun 2020 14:53:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730802AbgFOOxu (ORCPT ); Mon, 15 Jun 2020 10:53:50 -0400 Received: from mga14.intel.com ([192.55.52.115]:56331 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730794AbgFOOxr (ORCPT ); Mon, 15 Jun 2020 10:53:47 -0400 IronPort-SDR: KRkTTQpRPRnNfosc8UQgW3KrfRvn/lBBmEVSTkTKhBeNeg4uxmvomxGXylLzZEisvgSisEAJ3H 8dWEsIe+MxPg== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2020 07:53:46 -0700 IronPort-SDR: hBkuUtQL8+lhTWXLYi651EBCBrGOEnQVfzIuldPKgK9Hg1HqC5sQmkx3kq2cejv4s2HjL2N4xD LCQ6U6PgIXpQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,514,1583222400"; d="scan'208";a="382567032" Received: from romley-ivt3.sc.intel.com ([172.25.110.60]) by fmsmga001.fm.intel.com with ESMTP; 15 Jun 2020 07:53:46 -0700 Date: Mon, 15 Jun 2020 07:53:46 -0700 From: Fenghua Yu To: Peter Zijlstra Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , H Peter Anvin , David Woodhouse , Lu Baolu , Frederic Barrat , Andrew Donnellan , Felix Kuehling , Joerg Roedel , Dave Hansen , Tony Luck , Ashok Raj , Jacob Jun Pan , Dave Jiang , Yu-cheng Yu , Sohil Mehta , Ravi V Shankar , linux-kernel , x86 , iommu@lists.linux-foundation.org, amd-gfx , linuxppc-dev Subject: Re: [PATCH v2 00/12] x86: tag application address space for devices Message-ID: <20200615145345.GA13792@romley-ivt3.sc.intel.com> References: <1592008893-9388-1-git-send-email-fenghua.yu@intel.com> <20200615075202.GI2497@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200615075202.GI2497@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Peter, On Mon, Jun 15, 2020 at 09:52:02AM +0200, Peter Zijlstra wrote: > On Fri, Jun 12, 2020 at 05:41:21PM -0700, Fenghua Yu wrote: > > > This series only provides simple and basic support for ENQCMD and the MSR: > > 1. Clean up type definitions (patch 1-3). These patches can be in a > > separate series. > > - Define "pasid" as "unsigned int" consistently (patch 1 and 2). > > - Define "flags" as "unsigned int" > > 2. Explain different various technical terms used in the series (patch 4). > > 3. Enumerate support for ENQCMD in the processor (patch 5). > > 4. Handle FPU PASID state and the MSR during context switch (patches 6-7). > > 5. Define "pasid" in mm_struct (patch 8). > > 5. Clear PASID state for new mm and forked and cloned thread (patch 9-10). > > 6. Allocate and free PASID for a process (patch 11). > > 7. Fix up the PASID MSR in #GP handler when one thread in a process > > executes ENQCMD for the first time (patches 12). > > If this is per mm, should not switch_mm() update the MSR ? I'm not > seeing that, nor do I see it explained why not. PASID value is per mm and all threads in a process have the same PASID value in the MSR. However, the MSR is per thread and is context switched by XSAVES/XRSTROS in patches 6-7. Thanks. -Fenghua