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 smtp4.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 smtp.lore.kernel.org (Postfix) with ESMTPS id 0F40FC433EF for ; Wed, 29 Jun 2022 07:51:59 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id EEB7641995; Wed, 29 Jun 2022 07:51:58 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org EEB7641995 Authentication-Results: smtp4.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=K4tRYide X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id XepQk4GWyfqn; Wed, 29 Jun 2022 07:51:57 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp4.osuosl.org (Postfix) with ESMTPS id 18E37409C3; Wed, 29 Jun 2022 07:51:57 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org 18E37409C3 Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id CF7B4C0039; Wed, 29 Jun 2022 07:51:56 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [IPv6:2605:bc80:3010::137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 8C7FDC002D for ; Wed, 29 Jun 2022 07:51:55 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 58BE9409A0 for ; Wed, 29 Jun 2022 07:51:55 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org 58BE9409A0 X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id YhIc-LHUIb5h for ; Wed, 29 Jun 2022 07:51:54 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org 451B1409C3 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by smtp4.osuosl.org (Postfix) with ESMTPS id 451B1409C3 for ; Wed, 29 Jun 2022 07:51:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1656489114; x=1688025114; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=+H3iqUVrNt1aGjueQ2PCPg/gSRm34eU6k9Nmq35zT4I=; b=K4tRYidevQR5KQ3noedBNLpVSzXNOJhjZTmVvCW9q4mdDrw0ZnQxbpV4 96r15ZOogWOjZMjGumHJ91mYy8zg7M6yfFCV5PsXvKHYEcFLCHB7+RCAI RZulqfE8zetsCSQmV2L8i/iAAHnNa+xGdw3A8K3QiCxf5EJUpKcJ/IJJP db8JkBsvd4vvYwKDPEweUVcjjZT/KIDHfKuHP1KNYTSXq3I2oy+qgdJed 3YQLMUYthat/P5NK9Dl6hrW7jRpXjiVeDCels9hrDZgaNoQR59XxHnC8R gR5TQO5Q4lRFRqlYLjPXJHH30n6RQ4Yvul6jVpP+O1MD5vFNTgkTbp1dr A==; X-IronPort-AV: E=McAfee;i="6400,9594,10392"; a="262362914" X-IronPort-AV: E=Sophos;i="5.92,230,1650956400"; d="scan'208";a="262362914" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jun 2022 00:51:53 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.92,230,1650956400"; d="scan'208";a="588209580" Received: from allen-box.sh.intel.com ([10.239.159.48]) by orsmga007.jf.intel.com with ESMTP; 29 Jun 2022 00:51:51 -0700 From: Lu Baolu To: iommu@lists.linux-foundation.org, iommu@lists.linux.dev Subject: [PATCH v3 01/11] iommu/vt-d: debugfs: Remove device_domain_lock usage Date: Wed, 29 Jun 2022 15:47:15 +0800 Message-Id: <20220629074725.2331441-2-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220629074725.2331441-1-baolu.lu@linux.intel.com> References: <20220629074725.2331441-1-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 --- 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 mga04.intel.com (mga04.intel.com [192.55.52.120]) (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 D41737EB for ; Wed, 29 Jun 2022 07:51:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1656489119; x=1688025119; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=+H3iqUVrNt1aGjueQ2PCPg/gSRm34eU6k9Nmq35zT4I=; b=iArYcH3eWb8mO+6hVaLNb9eo5foCtZtAd92n9o6VaO1G3WtpL0VZt0Kk T7G6sj9hmONRRNfSJHE0q15AD1TFpC53imW7JqGJGoyEdSwPkDNXPOtA+ A4bUMTunt2MAtQiLPs2Dqxk/9OZzKdU4ZrEhBS4T2ff3Ik6JXu52VsQqU Pf6MVBS21QnQA8qS3fppRve4GdseDG9HK2WMFoeNbtxQpcjqK3y347RQa xWtugwwUZs6vpEqC4KgaclEo7NKYszBk6hCXWEyW/v5XW/IMYt3fLUtKA IT5+WaxJIC1B/3qEZSZRTtemakGocM8IsrpGBo7AAfKb1+n38VU2NPoG6 g==; X-IronPort-AV: E=McAfee;i="6400,9594,10392"; a="280718498" X-IronPort-AV: E=Sophos;i="5.92,230,1650956400"; d="scan'208";a="280718498" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jun 2022 00:51:54 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.92,230,1650956400"; d="scan'208";a="588209580" Received: from allen-box.sh.intel.com ([10.239.159.48]) by orsmga007.jf.intel.com with ESMTP; 29 Jun 2022 00:51:51 -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 v3 01/11] iommu/vt-d: debugfs: Remove device_domain_lock usage Date: Wed, 29 Jun 2022 15:47:15 +0800 Message-ID: <20220629074725.2331441-2-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220629074725.2331441-1-baolu.lu@linux.intel.com> References: <20220629074725.2331441-1-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: <20220629074715.lTjyumTiAcEXGUkjwLtLLfUg6D8jOX2GO2ce9h-npHw@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 --- 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