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iommufd: Disallow allocating nested parent domain with fault ID

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[ 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/bd1655c6-8b2f-4cfa-adb1-badc00d01811@intel.com/

Link: https://patch.msgid.link/r/20250226104012.82079-1-yi.l.liu@intel.com
Suggested-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Yi Liu
2025-02-26 02:40:12 -08:00
committed by Greg Kroah-Hartman
parent af73c8fd73
commit 4176d6f2a6
2 changed files with 7 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/iommu/iommufd/hw_pagetable.c
View File

@@ -122,6 +122,9 @@ 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);

4
tools/testing/selftests/iommu/iommufd.c
View File

@@ -289,6 +289,10 @@ 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,