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 Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 45A77C433EF for ; Wed, 6 Jul 2022 02:59:59 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id C25AD60AED; Wed, 6 Jul 2022 02:59:58 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp3.osuosl.org C25AD60AED Authentication-Results: smtp3.osuosl.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=FVx1bso/ X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id lJPKv4AcofAj; Wed, 6 Jul 2022 02:59:57 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp3.osuosl.org (Postfix) with ESMTPS id 722B860F4D; Wed, 6 Jul 2022 02:59:57 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp3.osuosl.org 722B860F4D Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 4AB40C0071; Wed, 6 Jul 2022 02:59:57 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id ECA82C0070 for ; Wed, 6 Jul 2022 02:59:55 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id D27B5400FE for ; Wed, 6 Jul 2022 02:59:54 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org D27B5400FE Authentication-Results: smtp2.osuosl.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=FVx1bso/ X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id oOjVfWi7-s2C for ; Wed, 6 Jul 2022 02:59:54 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org 113C6405BA Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by smtp2.osuosl.org (Postfix) with ESMTPS id 113C6405BA for ; Wed, 6 Jul 2022 02:59:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1657076394; x=1688612394; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=RglkaDn/jOyxV3iDLdnwbZrQLmp90jV1b+cWCbFzid4=; b=FVx1bso/bIZqsJtratcjZqTTeTBgxJOZ/xm4bPZWeZ8B/VVf0rDzLCzP PjdAJy1ObNc4cImWaU8WMoniOw26hWVRwrcgFMIshayPwx2UCyDcqvCUw /VZv75+dFvJ68qL+LYFu7fzOBaA+xGHalPTX/PdenPcGiG4PMmzLhlCkn 1rHdG2XJ3FTsYDehyXVpLtG9+gjAIEWI8E+icED1Oxgu2v1BqudW/+dRq eJBcFZYh2QGO0wCB0y+Gfq5iDtfnQoQt67cLDKNNLB2xe7yu8lB9C2cpe h1wo52/Z/v34Wgg0SXAycvxUIJj+defD4K66j51FJXVomitCbOeV5hlaF A==; X-IronPort-AV: E=McAfee;i="6400,9594,10399"; a="272409525" X-IronPort-AV: E=Sophos;i="5.92,248,1650956400"; d="scan'208";a="272409525" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jul 2022 19:59:53 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.92,248,1650956400"; d="scan'208";a="567874761" Received: from allen-box.sh.intel.com ([10.239.159.48]) by orsmga006.jf.intel.com with ESMTP; 05 Jul 2022 19:59:51 -0700 From: Lu Baolu To: iommu@lists.linux-foundation.org, iommu@lists.linux.dev Subject: [PATCH v4 01/11] iommu/vt-d: debugfs: Remove device_domain_lock usage Date: Wed, 6 Jul 2022 10:55:14 +0800 Message-Id: <20220706025524.2904370-2-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220706025524.2904370-1-baolu.lu@linux.intel.com> References: <20220706025524.2904370-1-baolu.lu@linux.intel.com> MIME-Version: 1.0 Cc: Kevin Tian , Ashok Raj , linux-kernel@vger.kernel.org, Jacob jun Pan 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" The domain_translation_struct debugfs node is used to dump the DMAR page tables for the PCI devices. It potentially races with setting domains to devices. The existing code uses the global spinlock device_domain_lock to avoid the races. This removes the use of device_domain_lock outside of iommu.c by replacing it with the group mutex lock. Using the group mutex lock is cleaner and more compatible to following cleanups. Signed-off-by: Lu Baolu Reviewed-by: Kevin Tian --- drivers/iommu/intel/iommu.h | 1 - drivers/iommu/intel/debugfs.c | 43 +++++++++++++++++++++++++---------- drivers/iommu/intel/iommu.c | 2 +- 3 files changed, 32 insertions(+), 14 deletions(-) diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h index 8285fcfa5fea..8deb745d8b36 100644 --- a/drivers/iommu/intel/iommu.h +++ b/drivers/iommu/intel/iommu.h @@ -480,7 +480,6 @@ enum { #define VTD_FLAG_SVM_CAPABLE (1 << 2) extern int intel_iommu_sm; -extern spinlock_t device_domain_lock; #define sm_supported(iommu) (intel_iommu_sm && ecap_smts((iommu)->ecap)) #define pasid_supported(iommu) (sm_supported(iommu) && \ diff --git a/drivers/iommu/intel/debugfs.c b/drivers/iommu/intel/debugfs.c index d927ef10641b..6e1a3f88abc8 100644 --- a/drivers/iommu/intel/debugfs.c +++ b/drivers/iommu/intel/debugfs.c @@ -342,13 +342,13 @@ static void pgtable_walk_level(struct seq_file *m, struct dma_pte *pde, } } -static int show_device_domain_translation(struct device *dev, void *data) +static int __show_device_domain_translation(struct device *dev, void *data) { - struct device_domain_info *info = dev_iommu_priv_get(dev); - struct dmar_domain *domain = info->domain; + struct dmar_domain *domain; struct seq_file *m = data; u64 path[6] = { 0 }; + domain = to_dmar_domain(iommu_get_domain_for_dev(dev)); if (!domain) return 0; @@ -359,20 +359,39 @@ static int show_device_domain_translation(struct device *dev, void *data) pgtable_walk_level(m, domain->pgd, domain->agaw + 2, 0, path); seq_putc(m, '\n'); - return 0; + /* Don't iterate */ + return 1; } -static int domain_translation_struct_show(struct seq_file *m, void *unused) +static int show_device_domain_translation(struct device *dev, void *data) { - unsigned long flags; - int ret; + struct iommu_group *group; - spin_lock_irqsave(&device_domain_lock, flags); - ret = bus_for_each_dev(&pci_bus_type, NULL, m, - show_device_domain_translation); - spin_unlock_irqrestore(&device_domain_lock, flags); + group = iommu_group_get(dev); + if (group) { + /* + * The group->mutex is held across the callback, which will + * block calls to iommu_attach/detach_group/device. Hence, + * the domain of the device will not change during traversal. + * + * All devices in an iommu group share a single domain, hence + * we only dump the domain of the first device. Even though, + * this code still possibly races with the iommu_unmap() + * interface. This could be solved by RCU-freeing the page + * table pages in the iommu_unmap() path. + */ + iommu_group_for_each_dev(group, data, + __show_device_domain_translation); + iommu_group_put(group); + } - return ret; + return 0; +} + +static int domain_translation_struct_show(struct seq_file *m, void *unused) +{ + return bus_for_each_dev(&pci_bus_type, NULL, m, + show_device_domain_translation); } DEFINE_SHOW_ATTRIBUTE(domain_translation_struct); diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 10bda4bec8fe..3b6571681bdd 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -314,7 +314,7 @@ static int iommu_skip_te_disable; #define IDENTMAP_GFX 2 #define IDENTMAP_AZALIA 4 -DEFINE_SPINLOCK(device_domain_lock); +static DEFINE_SPINLOCK(device_domain_lock); static LIST_HEAD(device_domain_list); const struct iommu_ops intel_iommu_ops; -- 2.25.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4C26917EF for ; Wed, 6 Jul 2022 03:00:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1657076405; x=1688612405; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=RglkaDn/jOyxV3iDLdnwbZrQLmp90jV1b+cWCbFzid4=; b=epmdikPR6YBEmhRmeyuGfhfJ3pQDdCZc3LPDDzD7ENtrXCeG4GY+Jqub rsQASpg2QQ15sWuC6p7HvAllKucUjzgg0ufZAchy/kvDK0yJ05AWtk/Wb Ofya2OjdpfaFOK6kYCnsBYugqHqsS/iqg1rouTIbkAhtBIjiwHuFEaOzW yEdtKdc4nt/tnkjWyatnz1YJuH6c/9AxLxDHz+rZ6dt0KTI4dpuv1PKi/ dKM6cU39WYnlbs+bmTtN7QEmeeNcFfe98OHZQIdB+kP/2mLBrVGEToZ7w jQhe+9ur9oFEaGk4xI4WWbpRfbiibKILwmUuo9r/s+1lNbe2yjA9az9LD Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10399"; a="283650845" X-IronPort-AV: E=Sophos;i="5.92,248,1650956400"; d="scan'208";a="283650845" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jul 2022 20:00:04 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.92,248,1650956400"; d="scan'208";a="567874761" Received: from allen-box.sh.intel.com ([10.239.159.48]) by orsmga006.jf.intel.com with ESMTP; 05 Jul 2022 19:59:51 -0700 From: Lu Baolu To: iommu@lists.linux-foundation.org, iommu@lists.linux.dev Cc: Kevin Tian , Ashok Raj , Liu Yi L , Jacob jun Pan , linux-kernel@vger.kernel.org, Lu Baolu Subject: [PATCH v4 01/11] iommu/vt-d: debugfs: Remove device_domain_lock usage Date: Wed, 6 Jul 2022 10:55:14 +0800 Message-ID: <20220706025524.2904370-2-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220706025524.2904370-1-baolu.lu@linux.intel.com> References: <20220706025524.2904370-1-baolu.lu@linux.intel.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID: <20220706025514.irlAS9VZoaWOh1pOv_ehgvHU6RL-wsfrjjvOU0J_Uw4@z> The domain_translation_struct debugfs node is used to dump the DMAR page tables for the PCI devices. It potentially races with setting domains to devices. The existing code uses the global spinlock device_domain_lock to avoid the races. This removes the use of device_domain_lock outside of iommu.c by replacing it with the group mutex lock. Using the group mutex lock is cleaner and more compatible to following cleanups. Signed-off-by: Lu Baolu Reviewed-by: Kevin Tian --- drivers/iommu/intel/iommu.h | 1 - drivers/iommu/intel/debugfs.c | 43 +++++++++++++++++++++++++---------- drivers/iommu/intel/iommu.c | 2 +- 3 files changed, 32 insertions(+), 14 deletions(-) diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h index 8285fcfa5fea..8deb745d8b36 100644 --- a/drivers/iommu/intel/iommu.h +++ b/drivers/iommu/intel/iommu.h @@ -480,7 +480,6 @@ enum { #define VTD_FLAG_SVM_CAPABLE (1 << 2) extern int intel_iommu_sm; -extern spinlock_t device_domain_lock; #define sm_supported(iommu) (intel_iommu_sm && ecap_smts((iommu)->ecap)) #define pasid_supported(iommu) (sm_supported(iommu) && \ diff --git a/drivers/iommu/intel/debugfs.c b/drivers/iommu/intel/debugfs.c index d927ef10641b..6e1a3f88abc8 100644 --- a/drivers/iommu/intel/debugfs.c +++ b/drivers/iommu/intel/debugfs.c @@ -342,13 +342,13 @@ static void pgtable_walk_level(struct seq_file *m, struct dma_pte *pde, } } -static int show_device_domain_translation(struct device *dev, void *data) +static int __show_device_domain_translation(struct device *dev, void *data) { - struct device_domain_info *info = dev_iommu_priv_get(dev); - struct dmar_domain *domain = info->domain; + struct dmar_domain *domain; struct seq_file *m = data; u64 path[6] = { 0 }; + domain = to_dmar_domain(iommu_get_domain_for_dev(dev)); if (!domain) return 0; @@ -359,20 +359,39 @@ static int show_device_domain_translation(struct device *dev, void *data) pgtable_walk_level(m, domain->pgd, domain->agaw + 2, 0, path); seq_putc(m, '\n'); - return 0; + /* Don't iterate */ + return 1; } -static int domain_translation_struct_show(struct seq_file *m, void *unused) +static int show_device_domain_translation(struct device *dev, void *data) { - unsigned long flags; - int ret; + struct iommu_group *group; - spin_lock_irqsave(&device_domain_lock, flags); - ret = bus_for_each_dev(&pci_bus_type, NULL, m, - show_device_domain_translation); - spin_unlock_irqrestore(&device_domain_lock, flags); + group = iommu_group_get(dev); + if (group) { + /* + * The group->mutex is held across the callback, which will + * block calls to iommu_attach/detach_group/device. Hence, + * the domain of the device will not change during traversal. + * + * All devices in an iommu group share a single domain, hence + * we only dump the domain of the first device. Even though, + * this code still possibly races with the iommu_unmap() + * interface. This could be solved by RCU-freeing the page + * table pages in the iommu_unmap() path. + */ + iommu_group_for_each_dev(group, data, + __show_device_domain_translation); + iommu_group_put(group); + } - return ret; + return 0; +} + +static int domain_translation_struct_show(struct seq_file *m, void *unused) +{ + return bus_for_each_dev(&pci_bus_type, NULL, m, + show_device_domain_translation); } DEFINE_SHOW_ATTRIBUTE(domain_translation_struct); diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 10bda4bec8fe..3b6571681bdd 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -314,7 +314,7 @@ static int iommu_skip_te_disable; #define IDENTMAP_GFX 2 #define IDENTMAP_AZALIA 4 -DEFINE_SPINLOCK(device_domain_lock); +static DEFINE_SPINLOCK(device_domain_lock); static LIST_HEAD(device_domain_list); const struct iommu_ops intel_iommu_ops; -- 2.25.1