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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 4CDF1C2D0F1 for ; Mon, 30 Mar 2020 20:38:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2C79E20757 for ; Mon, 30 Mar 2020 20:38:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728817AbgC3UiM (ORCPT ); Mon, 30 Mar 2020 16:38:12 -0400 Received: from mga17.intel.com ([192.55.52.151]:58490 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728594AbgC3UiE (ORCPT ); Mon, 30 Mar 2020 16:38:04 -0400 IronPort-SDR: vqszXeXo7ocMPaC3Kfm7HHfmA1dqlLG+7uNghGeuaSAYSbAy0Vg3y/rGmEoKCZabj0lbNzU6wu h1SQfvhd7F6w== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Mar 2020 13:38:03 -0700 IronPort-SDR: haPA83LUmCXaOVy56e3v+JFkDdVu3y6B6FE7X4vFztwvFpQv4+jjdYqzMMdB7J88eLzXyVu++Y Q2XhKUl3h9/A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,325,1580803200"; d="scan'208";a="242143895" Received: from romley-ivt3.sc.intel.com ([172.25.110.60]) by orsmga008.jf.intel.com with ESMTP; 30 Mar 2020 13:38:02 -0700 From: Fenghua Yu To: "Thomas Gleixner" , "Ingo Molnar" , "Borislav Petkov" , "H Peter Anvin" , "David Woodhouse" , "Lu Baolu" , "Dave Hansen" , "Tony Luck" , "Ashok Raj" , "Jacob Jun Pan" , "Dave Jiang" , "Sohil Mehta" , "Ravi V Shankar" Cc: "linux-kernel" , "x86" , iommu@lists.linux-foundation.org, Fenghua Yu Subject: [PATCH 6/7] x86/traps: Fix up invalid PASID Date: Mon, 30 Mar 2020 12:33:07 -0700 Message-Id: <1585596788-193989-7-git-send-email-fenghua.yu@intel.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1585596788-193989-1-git-send-email-fenghua.yu@intel.com> References: <1585596788-193989-1-git-send-email-fenghua.yu@intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A #GP fault is generated when ENQCMD instruction is executed without a valid PASID value programmed in. The #GP fault handler will initialize the current thread's PASID MSR. The following heuristic is used to avoid decoding the user instructions to determine the precise reason for the #GP fault: 1) If the mm for the process has not been allocated a PASID, this #GP cannot be fixed. 2) If the PASID MSR is already initialized, then the #GP was for some other reason 3) Try initializing the PASID MSR and returning. If the #GP was from an ENQCMD this will fix it. If not, the #GP fault will be repeated and we will hit case "2". Suggested-by: Thomas Gleixner Signed-off-by: Fenghua Yu Reviewed-by: Tony Luck --- arch/x86/include/asm/iommu.h | 1 + arch/x86/kernel/traps.c | 17 +++++++++++++++++ drivers/iommu/intel-svm.c | 37 ++++++++++++++++++++++++++++++++++++ 3 files changed, 55 insertions(+) diff --git a/arch/x86/include/asm/iommu.h b/arch/x86/include/asm/iommu.h index ed41259fe7ac..e9365a5d6f7d 100644 --- a/arch/x86/include/asm/iommu.h +++ b/arch/x86/include/asm/iommu.h @@ -27,5 +27,6 @@ arch_rmrr_sanity_check(struct acpi_dmar_reserved_memory *rmrr) } void __free_pasid(struct mm_struct *mm); +bool __fixup_pasid_exception(void); #endif /* _ASM_X86_IOMMU_H */ diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 6ef00eb6fbb9..369b5ba94635 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -56,6 +56,7 @@ #include #include #include +#include #ifdef CONFIG_X86_64 #include @@ -488,6 +489,16 @@ static enum kernel_gp_hint get_kernel_gp_address(struct pt_regs *regs, return GP_CANONICAL; } +static bool fixup_pasid_exception(void) +{ + if (!IS_ENABLED(CONFIG_INTEL_IOMMU_SVM)) + return false; + if (!static_cpu_has(X86_FEATURE_ENQCMD)) + return false; + + return __fixup_pasid_exception(); +} + #define GPFSTR "general protection fault" dotraplinkage void do_general_protection(struct pt_regs *regs, long error_code) @@ -499,6 +510,12 @@ dotraplinkage void do_general_protection(struct pt_regs *regs, long error_code) int ret; RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU"); + + if (user_mode(regs) && fixup_pasid_exception()) { + cond_local_irq_enable(regs); + return; + } + cond_local_irq_enable(regs); if (static_cpu_has(X86_FEATURE_UMIP)) { diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c index da718a49e91e..5ed39a022adb 100644 --- a/drivers/iommu/intel-svm.c +++ b/drivers/iommu/intel-svm.c @@ -759,3 +759,40 @@ void __free_pasid(struct mm_struct *mm) */ ioasid_free(pasid); } + +/* + * Fix up the PASID MSR if possible. + * + * But if the #GP was due to another reason, a second #GP might be triggered + * to force proper behavior. + */ +bool __fixup_pasid_exception(void) +{ + struct mm_struct *mm; + bool ret = true; + u64 pasid_msr; + int pasid; + + mm = get_task_mm(current); + /* This #GP was triggered from user mode. So mm cannot be NULL. */ + pasid = mm->context.pasid; + /* Ensure this process has been bound to a PASID. */ + if (!pasid) { + ret = false; + goto out; + } + + /* Check to see if the PASID MSR has already been set for this task. */ + rdmsrl(MSR_IA32_PASID, pasid_msr); + if (pasid_msr & MSR_IA32_PASID_VALID) { + ret = false; + goto out; + } + + /* Fix up the MSR. */ + wrmsrl(MSR_IA32_PASID, pasid | MSR_IA32_PASID_VALID); +out: + mmput(mm); + + return ret; +} -- 2.19.1 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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 B6EE5C2BA13 for ; Mon, 30 Mar 2020 20:38:07 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (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 94EB0207FF for ; Mon, 30 Mar 2020 20:38:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 94EB0207FF 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 whitealder.osuosl.org (Postfix) with ESMTP id 7B5E887C51; Mon, 30 Mar 2020 20:38:07 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id VXMfj8RQs9Mi; Mon, 30 Mar 2020 20:38:05 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by whitealder.osuosl.org (Postfix) with ESMTP id 7B5C887CAE; Mon, 30 Mar 2020 20:38:05 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 726C6C1D89; Mon, 30 Mar 2020 20:38:05 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 41A98C1D7E for ; Mon, 30 Mar 2020 20:38:04 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id 2FB7E20416 for ; Mon, 30 Mar 2020 20:38:04 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id g3wrpb8Q9YGR for ; Mon, 30 Mar 2020 20:38:03 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by silver.osuosl.org (Postfix) with ESMTPS id 68B8E22851 for ; Mon, 30 Mar 2020 20:38:03 +0000 (UTC) IronPort-SDR: QTFydAUam5xS401oEoZ+uZrdpGM9VaBMRxJoM8i32ltP1SV8F9TMYlnNVxBkmoTa9LPnOgJn+P +n3wzUJzIkVg== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Mar 2020 13:38:03 -0700 IronPort-SDR: haPA83LUmCXaOVy56e3v+JFkDdVu3y6B6FE7X4vFztwvFpQv4+jjdYqzMMdB7J88eLzXyVu++Y Q2XhKUl3h9/A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,325,1580803200"; d="scan'208";a="242143895" Received: from romley-ivt3.sc.intel.com ([172.25.110.60]) by orsmga008.jf.intel.com with ESMTP; 30 Mar 2020 13:38:02 -0700 From: Fenghua Yu To: "Thomas Gleixner" , "Ingo Molnar" , "Borislav Petkov" , "H Peter Anvin" , "David Woodhouse" , "Lu Baolu" , "Dave Hansen" , "Tony Luck" , "Ashok Raj" , "Jacob Jun Pan" , "Dave Jiang" , "Sohil Mehta" , "Ravi V Shankar" Subject: [PATCH 6/7] x86/traps: Fix up invalid PASID Date: Mon, 30 Mar 2020 12:33:07 -0700 Message-Id: <1585596788-193989-7-git-send-email-fenghua.yu@intel.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1585596788-193989-1-git-send-email-fenghua.yu@intel.com> References: <1585596788-193989-1-git-send-email-fenghua.yu@intel.com> Cc: Fenghua Yu , iommu@lists.linux-foundation.org, x86 , linux-kernel 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" A #GP fault is generated when ENQCMD instruction is executed without a valid PASID value programmed in. The #GP fault handler will initialize the current thread's PASID MSR. The following heuristic is used to avoid decoding the user instructions to determine the precise reason for the #GP fault: 1) If the mm for the process has not been allocated a PASID, this #GP cannot be fixed. 2) If the PASID MSR is already initialized, then the #GP was for some other reason 3) Try initializing the PASID MSR and returning. If the #GP was from an ENQCMD this will fix it. If not, the #GP fault will be repeated and we will hit case "2". Suggested-by: Thomas Gleixner Signed-off-by: Fenghua Yu Reviewed-by: Tony Luck --- arch/x86/include/asm/iommu.h | 1 + arch/x86/kernel/traps.c | 17 +++++++++++++++++ drivers/iommu/intel-svm.c | 37 ++++++++++++++++++++++++++++++++++++ 3 files changed, 55 insertions(+) diff --git a/arch/x86/include/asm/iommu.h b/arch/x86/include/asm/iommu.h index ed41259fe7ac..e9365a5d6f7d 100644 --- a/arch/x86/include/asm/iommu.h +++ b/arch/x86/include/asm/iommu.h @@ -27,5 +27,6 @@ arch_rmrr_sanity_check(struct acpi_dmar_reserved_memory *rmrr) } void __free_pasid(struct mm_struct *mm); +bool __fixup_pasid_exception(void); #endif /* _ASM_X86_IOMMU_H */ diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 6ef00eb6fbb9..369b5ba94635 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -56,6 +56,7 @@ #include #include #include +#include #ifdef CONFIG_X86_64 #include @@ -488,6 +489,16 @@ static enum kernel_gp_hint get_kernel_gp_address(struct pt_regs *regs, return GP_CANONICAL; } +static bool fixup_pasid_exception(void) +{ + if (!IS_ENABLED(CONFIG_INTEL_IOMMU_SVM)) + return false; + if (!static_cpu_has(X86_FEATURE_ENQCMD)) + return false; + + return __fixup_pasid_exception(); +} + #define GPFSTR "general protection fault" dotraplinkage void do_general_protection(struct pt_regs *regs, long error_code) @@ -499,6 +510,12 @@ dotraplinkage void do_general_protection(struct pt_regs *regs, long error_code) int ret; RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU"); + + if (user_mode(regs) && fixup_pasid_exception()) { + cond_local_irq_enable(regs); + return; + } + cond_local_irq_enable(regs); if (static_cpu_has(X86_FEATURE_UMIP)) { diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c index da718a49e91e..5ed39a022adb 100644 --- a/drivers/iommu/intel-svm.c +++ b/drivers/iommu/intel-svm.c @@ -759,3 +759,40 @@ void __free_pasid(struct mm_struct *mm) */ ioasid_free(pasid); } + +/* + * Fix up the PASID MSR if possible. + * + * But if the #GP was due to another reason, a second #GP might be triggered + * to force proper behavior. + */ +bool __fixup_pasid_exception(void) +{ + struct mm_struct *mm; + bool ret = true; + u64 pasid_msr; + int pasid; + + mm = get_task_mm(current); + /* This #GP was triggered from user mode. So mm cannot be NULL. */ + pasid = mm->context.pasid; + /* Ensure this process has been bound to a PASID. */ + if (!pasid) { + ret = false; + goto out; + } + + /* Check to see if the PASID MSR has already been set for this task. */ + rdmsrl(MSR_IA32_PASID, pasid_msr); + if (pasid_msr & MSR_IA32_PASID_VALID) { + ret = false; + goto out; + } + + /* Fix up the MSR. */ + wrmsrl(MSR_IA32_PASID, pasid | MSR_IA32_PASID_VALID); +out: + mmput(mm); + + return ret; +} -- 2.19.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu