From: Yi Liu <[email protected]> [ Upstream commit 1062d81086156e42878d701b816d2f368b53a77c ]
Allocating a domain with a fault ID indicates that the domain is faultable. However, there is a gap for the nested parent domain to support PRI. Some hardware lacks the capability to distinguish whether PRI occurs at stage 1 or stage 2. This limitation may require software-based page table walking to resolve. Since no in-tree IOMMU driver currently supports this functionality, it is disallowed. For more details, refer to the related discussion at [1]. [1] https://lore.kernel.org/linux-iommu/[email protected]/ Link: https://patch.msgid.link/r/[email protected] Suggested-by: Lu Baolu <[email protected]> Signed-off-by: Yi Liu <[email protected]> Reviewed-by: Kevin Tian <[email protected]> Reviewed-by: Lu Baolu <[email protected]> Signed-off-by: Jason Gunthorpe <[email protected]> Signed-off-by: Sasha Levin <[email protected]> --- drivers/iommu/iommufd/hw_pagetable.c | 3 +++ tools/testing/selftests/iommu/iommufd.c | 4 ++++ 2 files changed, 7 insertions(+) diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c index 598be26a14e28..9b5b0b8522299 100644 --- a/drivers/iommu/iommufd/hw_pagetable.c +++ b/drivers/iommu/iommufd/hw_pagetable.c @@ -126,6 +126,9 @@ iommufd_hwpt_paging_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas, if ((flags & IOMMU_HWPT_ALLOC_DIRTY_TRACKING) && !device_iommu_capable(idev->dev, IOMMU_CAP_DIRTY_TRACKING)) return ERR_PTR(-EOPNOTSUPP); + if ((flags & IOMMU_HWPT_FAULT_ID_VALID) && + (flags & IOMMU_HWPT_ALLOC_NEST_PARENT)) + return ERR_PTR(-EOPNOTSUPP); hwpt_paging = __iommufd_object_alloc( ictx, hwpt_paging, IOMMUFD_OBJ_HWPT_PAGING, common.obj); diff --git a/tools/testing/selftests/iommu/iommufd.c b/tools/testing/selftests/iommu/iommufd.c index a1b2b657999dc..618c03bb6509b 100644 --- a/tools/testing/selftests/iommu/iommufd.c +++ b/tools/testing/selftests/iommu/iommufd.c @@ -439,6 +439,10 @@ TEST_F(iommufd_ioas, alloc_hwpt_nested) &test_hwpt_id); test_err_hwpt_alloc(EINVAL, self->device_id, self->device_id, 0, &test_hwpt_id); + test_err_hwpt_alloc(EOPNOTSUPP, self->device_id, self->ioas_id, + IOMMU_HWPT_ALLOC_NEST_PARENT | + IOMMU_HWPT_FAULT_ID_VALID, + &test_hwpt_id); test_cmd_hwpt_alloc(self->device_id, self->ioas_id, IOMMU_HWPT_ALLOC_NEST_PARENT, -- 2.39.5
