diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 4c3707384bd9..744e4e6b8d72 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -2204,6 +2204,8 @@ __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, attr |= DMA_FL_PTE_DIRTY; } + domain->has_mappings = true; + pteval = ((phys_addr_t)phys_pfn << VTD_PAGE_SHIFT) | attr; while (nr_pages > 0) { @@ -4309,7 +4311,8 @@ static bool intel_iommu_enforce_cache_coherency(struct iommu_domain *domain) return true; spin_lock_irqsave(&dmar_domain->lock, flags); - if (!domain_support_force_snooping(dmar_domain)) { + if (!domain_support_force_snooping(dmar_domain) || + (!dmar_domain->use_first_level && dmar_domain->has_mappings)) { spin_unlock_irqrestore(&dmar_domain->lock, flags); return false; } diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h index 7dac94f62b4e..e6a3e7065616 100644 --- a/drivers/iommu/intel/iommu.h +++ b/drivers/iommu/intel/iommu.h @@ -592,6 +592,9 @@ struct dmar_domain { * otherwise, goes through the second * level. */ + u8 has_mappings:1; /* Has mappings configured through + * iommu_map() interface. + */ spinlock_t lock; /* Protect device tracking lists */ struct list_head devices; /* all devices' list */