From: Lu Baolu Date: Tue, 12 Jul 2022 00:08:53 +0000 (+0800) Subject: iommu/vt-d: Remove clearing translation data in disable_dmar_iommu() X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=98f7b0db4976690e47701b702ae314375101e327;p=linux.git iommu/vt-d: Remove clearing translation data in disable_dmar_iommu() 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 Reviewed-by: Kevin Tian Link: https://lore.kernel.org/r/20220706025524.2904370-3-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel --- diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 3b6571681bdd9..43aaec5bdd849 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); diff --git a/drivers/iommu/intel/pasid.h b/drivers/iommu/intel/pasid.h index bf5b937848b41..20c54e50f533c 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