From: Lu Baolu <baolu.lu@linux.intel.com> To: iommu@lists.linux-foundation.org, iommu@lists.linux.dev Cc: Kevin Tian <kevin.tian@intel.com>, Ashok Raj <ashok.raj@intel.com>, Liu Yi L <yi.l.liu@intel.com>, Jacob jun Pan <jacob.jun.pan@intel.com>, linux-kernel@vger.kernel.org, Lu Baolu <baolu.lu@linux.intel.com> Subject: [PATCH v4 02/11] iommu/vt-d: Remove clearing translation data in disable_dmar_iommu() Date: Wed, 6 Jul 2022 10:55:15 +0800 [thread overview] Message-ID: <20220706025524.2904370-3-baolu.lu@linux.intel.com> (raw) In-Reply-To: <20220706025524.2904370-1-baolu.lu@linux.intel.com> The disable_dmar_iommu() is called when IOMMU initialization fails or the IOMMU is hot-removed from the system. In both cases, there is no need to clear the IOMMU translation data structures for devices. On the initialization path, the device probing only happens after the IOMMU is initialized successfully, hence there're no translation data structures. On the hot-remove path, there is no real use case where the IOMMU is hot-removed, but the devices that it manages are still alive in the system. The translation data structures were torn down during device release, hence there's no need to repeat it in IOMMU hot-remove path either. This removes the unnecessary code and only leaves a check. Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> --- drivers/iommu/intel/pasid.h | 1 + drivers/iommu/intel/iommu.c | 21 +++++++-------------- 2 files changed, 8 insertions(+), 14 deletions(-) diff --git a/drivers/iommu/intel/pasid.h b/drivers/iommu/intel/pasid.h index bf5b937848b4..20c54e50f533 100644 --- a/drivers/iommu/intel/pasid.h +++ b/drivers/iommu/intel/pasid.h @@ -39,6 +39,7 @@ * only and pass-through transfer modes. */ #define FLPT_DEFAULT_DID 1 +#define NUM_RESERVED_DID 2 /* * The SUPERVISOR_MODE flag indicates a first level translation which diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 3b6571681bdd..43aaec5bdd84 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -1716,23 +1716,16 @@ static int iommu_init_domains(struct intel_iommu *iommu) static void disable_dmar_iommu(struct intel_iommu *iommu) { - struct device_domain_info *info, *tmp; - unsigned long flags; - if (!iommu->domain_ids) return; - spin_lock_irqsave(&device_domain_lock, flags); - list_for_each_entry_safe(info, tmp, &device_domain_list, global) { - if (info->iommu != iommu) - continue; - - if (!info->dev || !info->domain) - continue; - - __dmar_remove_one_dev_info(info); - } - spin_unlock_irqrestore(&device_domain_lock, flags); + /* + * All iommu domains must have been detached from the devices, + * hence there should be no domain IDs in use. + */ + if (WARN_ON(bitmap_weight(iommu->domain_ids, cap_ndoms(iommu->cap)) + > NUM_RESERVED_DID)) + return; if (iommu->gcmd & DMA_GCMD_TE) iommu_disable_translation(iommu); -- 2.25.1
WARNING: multiple messages have this Message-ID (diff)
From: Lu Baolu <baolu.lu@linux.intel.com> To: iommu@lists.linux-foundation.org, iommu@lists.linux.dev Cc: Kevin Tian <kevin.tian@intel.com>, Ashok Raj <ashok.raj@intel.com>, linux-kernel@vger.kernel.org, Jacob jun Pan <jacob.jun.pan@intel.com> Subject: [PATCH v4 02/11] iommu/vt-d: Remove clearing translation data in disable_dmar_iommu() Date: Wed, 6 Jul 2022 10:55:15 +0800 [thread overview] Message-ID: <20220706025524.2904370-3-baolu.lu@linux.intel.com> (raw) In-Reply-To: <20220706025524.2904370-1-baolu.lu@linux.intel.com> The disable_dmar_iommu() is called when IOMMU initialization fails or the IOMMU is hot-removed from the system. In both cases, there is no need to clear the IOMMU translation data structures for devices. On the initialization path, the device probing only happens after the IOMMU is initialized successfully, hence there're no translation data structures. On the hot-remove path, there is no real use case where the IOMMU is hot-removed, but the devices that it manages are still alive in the system. The translation data structures were torn down during device release, hence there's no need to repeat it in IOMMU hot-remove path either. This removes the unnecessary code and only leaves a check. Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> --- drivers/iommu/intel/pasid.h | 1 + drivers/iommu/intel/iommu.c | 21 +++++++-------------- 2 files changed, 8 insertions(+), 14 deletions(-) diff --git a/drivers/iommu/intel/pasid.h b/drivers/iommu/intel/pasid.h index bf5b937848b4..20c54e50f533 100644 --- a/drivers/iommu/intel/pasid.h +++ b/drivers/iommu/intel/pasid.h @@ -39,6 +39,7 @@ * only and pass-through transfer modes. */ #define FLPT_DEFAULT_DID 1 +#define NUM_RESERVED_DID 2 /* * The SUPERVISOR_MODE flag indicates a first level translation which diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 3b6571681bdd..43aaec5bdd84 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -1716,23 +1716,16 @@ static int iommu_init_domains(struct intel_iommu *iommu) static void disable_dmar_iommu(struct intel_iommu *iommu) { - struct device_domain_info *info, *tmp; - unsigned long flags; - if (!iommu->domain_ids) return; - spin_lock_irqsave(&device_domain_lock, flags); - list_for_each_entry_safe(info, tmp, &device_domain_list, global) { - if (info->iommu != iommu) - continue; - - if (!info->dev || !info->domain) - continue; - - __dmar_remove_one_dev_info(info); - } - spin_unlock_irqrestore(&device_domain_lock, flags); + /* + * All iommu domains must have been detached from the devices, + * hence there should be no domain IDs in use. + */ + if (WARN_ON(bitmap_weight(iommu->domain_ids, cap_ndoms(iommu->cap)) + > NUM_RESERVED_DID)) + return; if (iommu->gcmd & DMA_GCMD_TE) iommu_disable_translation(iommu); -- 2.25.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2022-07-06 3:00 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-07-06 2:55 [PATCH v4 00/11] iommu/vt-d: Optimize the use of locks Lu Baolu 2022-07-06 2:55 ` Lu Baolu 2022-07-06 2:55 ` [PATCH v4 01/11] iommu/vt-d: debugfs: Remove device_domain_lock usage Lu Baolu 2022-07-06 2:55 ` Lu Baolu [not found] ` <849557ab-9c1b-a2ff-6fc6-6564f38d1187@linux.intel.com> 2022-07-07 9:18 ` Baolu Lu 2022-07-06 2:55 ` Lu Baolu [this message] 2022-07-06 2:55 ` [PATCH v4 02/11] iommu/vt-d: Remove clearing translation data in disable_dmar_iommu() Lu Baolu 2022-07-07 3:03 ` Tian, Kevin 2022-07-06 2:55 ` [PATCH v4 03/11] iommu/vt-d: Use pci_get_domain_bus_and_slot() in pgtable_walk() Lu Baolu 2022-07-06 2:55 ` Lu Baolu 2022-07-06 2:55 ` [PATCH v4 04/11] iommu/vt-d: Unnecessary spinlock for root table alloc and free Lu Baolu 2022-07-06 2:55 ` Lu Baolu 2022-07-06 2:55 ` [PATCH v4 05/11] iommu/vt-d: Replace spin_lock_irqsave() with spin_lock() Lu Baolu 2022-07-06 2:55 ` Lu Baolu 2022-07-06 2:55 ` [PATCH v4 06/11] iommu/vt-d: Acquiring lock in domain ID allocation helpers Lu Baolu 2022-07-06 2:55 ` Lu Baolu 2022-07-06 2:55 ` [PATCH v4 07/11] iommu/vt-d: Acquiring lock in pasid manipulation helpers Lu Baolu 2022-07-06 2:55 ` Lu Baolu 2022-07-06 2:55 ` [PATCH v4 08/11] iommu/vt-d: Check device list of domain in domain free path Lu Baolu 2022-07-06 2:55 ` Lu Baolu 2022-07-06 2:55 ` [PATCH v4 09/11] iommu/vt-d: Fold __dmar_remove_one_dev_info() into its caller Lu Baolu 2022-07-06 2:55 ` Lu Baolu 2022-07-06 2:55 ` [PATCH v4 10/11] iommu/vt-d: Use device_domain_lock accurately Lu Baolu 2022-07-06 2:55 ` Lu Baolu 2022-07-06 2:55 ` [PATCH v4 11/11] iommu/vt-d: Convert global spinlock into per domain lock Lu Baolu 2022-07-06 2:55 ` Lu Baolu
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