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=-10.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 777E1C433DF for ; Tue, 30 Jun 2020 23:45:30 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5233120781 for ; Tue, 30 Jun 2020 23:45:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5233120781 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 2E6C9876F3; Tue, 30 Jun 2020 23:45:30 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id i1DjIQzFqH92; Tue, 30 Jun 2020 23:45:29 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by fraxinus.osuosl.org (Postfix) with ESMTP id 1B57C876D6; Tue, 30 Jun 2020 23:45:29 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 091DDC08A6; Tue, 30 Jun 2020 23:45:29 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 3EA3FC0865 for ; Tue, 30 Jun 2020 23:45:22 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 2782E87676 for ; Tue, 30 Jun 2020 23:45:22 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id oxlUe_tGDZr0 for ; Tue, 30 Jun 2020 23:45:21 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by fraxinus.osuosl.org (Postfix) with ESMTPS id 344898727C for ; Tue, 30 Jun 2020 23:45:21 +0000 (UTC) IronPort-SDR: 8fdky7bgyZ6u3lfsXZmQ4Qn0rEeyVgpB7/1qs0EsrYen5bFBCMct3J8rw9dI7R4FYuEraqlDBc TWZAth70nYfA== X-IronPort-AV: E=McAfee;i="6000,8403,9668"; a="134710061" X-IronPort-AV: E=Sophos;i="5.75,298,1589266800"; d="scan'208";a="134710061" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Jun 2020 16:45:19 -0700 IronPort-SDR: re0RctowIT+yewnmQ6nNWhZ2y4/niYFMWBcICutZwpRc0G9agiACYu+lIMSxeFO2sCyXdE2lv8 3xNruEX7+8VA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,298,1589266800"; d="scan'208";a="386842574" Received: from romley-ivt3.sc.intel.com ([172.25.110.60]) by fmsmga001.fm.intel.com with ESMTP; 30 Jun 2020 16:44:54 -0700 From: Fenghua Yu To: "Thomas Gleixner" , "Joerg Roedel" , "Ingo Molnar" , "Borislav Petkov" , "Peter Zijlstra" , "H Peter Anvin" , "David Woodhouse" , "Lu Baolu" , "Felix Kuehling" , "Dave Hansen" , "Tony Luck" , "Jean-Philippe Brucker" , "Christoph Hellwig" , "Ashok Raj" , "Jacob Jun Pan" , "Dave Jiang" , "Sohil Mehta" , "Ravi V Shankar" Subject: [PATCH v5 09/12] x86/process: Clear PASID state for a newly forked/cloned thread Date: Tue, 30 Jun 2020 16:44:39 -0700 Message-Id: <1593560682-40814-10-git-send-email-fenghua.yu@intel.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1593560682-40814-1-git-send-email-fenghua.yu@intel.com> References: <1593560682-40814-1-git-send-email-fenghua.yu@intel.com> Cc: Fenghua Yu , iommu@lists.linux-foundation.org, x86 , linux-kernel , amd-gfx X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" The PASID state has to be cleared on forks, since the child has a different address space. The PASID is also cleared for thread clone. While it would be correct to inherit the PASID in this case, it is unknown whether the new task will use ENQCMD. Giving it the PASID "just in case" would have the downside of increased context switch overhead to setting the PASID MSR. Since #GP faults have to be handled on any threads that were created before the PASID was assigned to the mm of the process, newly created threads might as well be treated in a consistent way. Suggested-by: Thomas Gleixner Signed-off-by: Fenghua Yu Reviewed-by: Tony Luck --- v2: - Modify init_task_pasid(). arch/x86/kernel/process.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index f362ce0d5ac0..1b1492e337a6 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -121,6 +121,21 @@ static int set_new_tls(struct task_struct *p, unsigned long tls) return do_set_thread_area_64(p, ARCH_SET_FS, tls); } +/* Initialize the PASID state for the forked/cloned thread. */ +static void init_task_pasid(struct task_struct *task) +{ + struct ia32_pasid_state *ppasid; + + /* + * Initialize the PASID state so that the PASID MSR will be + * initialized to its initial state (0) by XRSTORS when the task is + * scheduled for the first time. + */ + ppasid = get_xsave_addr(&task->thread.fpu.state.xsave, XFEATURE_PASID); + if (ppasid) + ppasid->pasid = INIT_PASID; +} + int copy_thread_tls(unsigned long clone_flags, unsigned long sp, unsigned long arg, struct task_struct *p, unsigned long tls) { @@ -174,6 +189,9 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp, task_user_gs(p) = get_user_gs(current_pt_regs()); #endif + if (static_cpu_has(X86_FEATURE_ENQCMD)) + init_task_pasid(p); + /* Set a new TLS for the child thread? */ if (clone_flags & CLONE_SETTLS) ret = set_new_tls(p, tls); -- 2.19.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu