From e93e4a6363b8f812cb89f2b2d97cbaf017a3d7f8 Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Fri, 27 Feb 2026 11:25:37 -0400 Subject: [PATCH] iommu/riscv: Disable SADE In terms of the iommu subystem the SADE/GADE feature "3.4. IOMMU updating of PTE accessed (A) and dirty (D) updates" is called dirty tracking. There is no reason to enable HW support for this, and the HW cost associated with it, unless dirty tracking is actually enabled through iommufd. It should be a dynamic feature linked to user request. Further, without implementing the read dirty ops the whole thing is pointless. Do not set DC.tc.SADE just because the HW has support for dirty tracking. Tested-by: Vincent Chen Acked-by: Paul Walmsley # arch/riscv Reviewed-by: Tomasz Jeznach Tested-by: Tomasz Jeznach Signed-off-by: Jason Gunthorpe Signed-off-by: Joerg Roedel --- drivers/iommu/riscv/iommu.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/drivers/iommu/riscv/iommu.c b/drivers/iommu/riscv/iommu.c index fa2ebfd2f912..0b2903372470 100644 --- a/drivers/iommu/riscv/iommu.c +++ b/drivers/iommu/riscv/iommu.c @@ -810,7 +810,6 @@ struct riscv_iommu_domain { struct list_head bonds; spinlock_t lock; /* protect bonds list updates. */ int pscid; - bool amo_enabled; int numa_node; unsigned int pgd_mode; unsigned long *pgd_root; @@ -1201,8 +1200,6 @@ static int riscv_iommu_map_pages(struct iommu_domain *iommu_domain, if (!(prot & IOMMU_WRITE)) pte_prot = _PAGE_BASE | _PAGE_READ; - else if (domain->amo_enabled) - pte_prot = _PAGE_BASE | _PAGE_READ | _PAGE_WRITE; else pte_prot = _PAGE_BASE | _PAGE_READ | _PAGE_WRITE | _PAGE_DIRTY; @@ -1387,7 +1384,6 @@ static struct iommu_domain *riscv_iommu_alloc_paging_domain(struct device *dev) INIT_LIST_HEAD_RCU(&domain->bonds); spin_lock_init(&domain->lock); domain->numa_node = dev_to_node(iommu->dev); - domain->amo_enabled = !!(iommu->caps & RISCV_IOMMU_CAPABILITIES_AMO_HWAD); domain->pgd_mode = pgd_mode; domain->pgd_root = iommu_alloc_pages_node_sz(domain->numa_node, GFP_KERNEL_ACCOUNT, SZ_4K); @@ -1512,8 +1508,6 @@ static struct iommu_device *riscv_iommu_probe_device(struct device *dev) * the device directory. Do not mark the context valid yet. */ tc = 0; - if (iommu->caps & RISCV_IOMMU_CAPABILITIES_AMO_HWAD) - tc |= RISCV_IOMMU_DC_TC_SADE; for (i = 0; i < fwspec->num_ids; i++) { dc = riscv_iommu_get_dc(iommu, fwspec->ids[i]); if (!dc) {