[PATCH v2 09/19] iommufd: Allow hwpt_id to carry viommu_id for IOMMU_HWPT_INVALIDATE

Nicolin Chen
2024-08-27T17:01:58Z

With a VIOMMU object, use space can flush any IOMMU related cache that can
be directed using the viommu. It is similar to IOMMU_HWPT_INVALIDATE uAPI,
but can cover a wider range than IOTLB, such as device cache or desciprtor
cache.

Allow hwpt_id of the iommu_hwpt_invalidate structure to carry a viommu_id,
and reuse the IOMMU_HWPT_INVALIDATE uAPI for VIOMMU invalidations. Driver
can define a different structure for VIOMMU invalidations v.s. HWPT ones.

Update the uAPI, kdoc, and selftest case accordingly.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
drivers/iommu/iommufd/hw_pagetable.c | 32 +++++++++++++++++++------
include/uapi/linux/iommufd.h | 9 ++++---
tools/testing/selftests/iommu/iommufd.c | 4 ++--
3 files changed, 33 insertions(+), 12 deletions(-)

diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index 06adbcc304bc..6aaec1b32abc 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -432,7 +432,7 @@ int iommufd_hwpt_invalidate(struct iommufd_ucmd *ucmd)
.entry_len = cmd->entry_len,
.entry_num = cmd->entry_num,
};
- struct iommufd_hw_pagetable *hwpt;
+ struct iommufd_object *pt_obj;
u32 done_num = 0;
int rc;

@@ -446,17 +446,35 @@ int iommufd_hwpt_invalidate(struct iommufd_ucmd *ucmd)
goto out;
}

- hwpt = iommufd_get_hwpt_nested(ucmd, cmd->hwpt_id);
- if (IS_ERR(hwpt)) {
- rc = PTR_ERR(hwpt);
+ pt_obj = iommufd_get_object(ucmd->ictx, cmd->hwpt_id, IOMMUFD_OBJ_ANY);
+ if (IS_ERR(pt_obj)) {
+ rc = PTR_ERR(pt_obj);
goto out;
}
+ if (pt_obj->type == IOMMUFD_OBJ_HWPT_NESTED) {
+ struct iommufd_hw_pagetable *hwpt =
+ container_of(pt_obj, struct iommufd_hw_pagetable, obj);
+
+ rc = hwpt->domain->ops->cache_invalidate_user(hwpt->domain,
+ &data_array);
+ } else if (pt_obj->type == IOMMUFD_OBJ_VIOMMU) {
+ struct iommufd_viommu *viommu =
+ container_of(pt_obj, struct iommufd_viommu, obj);
+
+ if (!viommu->ops || !viommu->ops->cache_invalidate) {
+ rc = -EOPNOTSUPP;
+ goto out_put_pt;
+ }
+ rc = viommu->ops->cache_invalidate(viommu, &data_array);
+ } else {
+ rc = -EINVAL;
+ goto out_put_pt;
+ }

- rc = hwpt->domain->ops->cache_invalidate_user(hwpt->domain,
- &data_array);
done_num = data_array.entry_num;

- iommufd_put_object(ucmd->ictx, &hwpt->obj);
+out_put_pt:
+ iommufd_put_object(ucmd->ictx, pt_obj);
out:
cmd->entry_num = done_num;
if (iommufd_ucmd_respond(ucmd, sizeof(*cmd)))
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 1816e89c922d..fd7d16fd441d 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -729,7 +729,7 @@ struct iommu_hwpt_vtd_s1_invalidate {
/**
* struct iommu_hwpt_invalidate - ioctl(IOMMU_HWPT_INVALIDATE)
* @size: sizeof(struct iommu_hwpt_invalidate)
- * @hwpt_id: ID of a nested HWPT for cache invalidation
+ * @hwpt_id: ID of a nested HWPT or VIOMMU, for cache invalidation
* @data_uptr: User pointer to an array of driver-specific cache invalidation
* data.
* @data_type: One of enum iommu_hwpt_invalidate_data_type, defining the data
@@ -740,8 +740,11 @@ struct iommu_hwpt_vtd_s1_invalidate {
* Output the number of requests successfully handled by kernel.
* @__reserved: Must be 0.
*
- * Invalidate the iommu cache for user-managed page table. Modifications on a
- * user-managed page table should be followed by this operation to sync cache.
+ * Invalidate iommu cache for user-managed page table or vIOMMU. Modifications
+ * on a user-managed page table should be followed by this operation, if a HWPT
+ * is passed in via @hwpt_id. Other caches, such as device cache or descriptor
+ * cache can be flushed if a VIOMMU is passed in via the @hwpt_id field.
+ *
* Each ioctl can support one or more cache invalidation requests in the array
* that has a total size of @entry_len * @entry_num.
*
diff --git a/tools/testing/selftests/iommu/iommufd.c b/tools/testing/selftests/iommu/iommufd.c
index f383f3bc7c8b..12b5a8f78d4b 100644
--- a/tools/testing/selftests/iommu/iommufd.c
+++ b/tools/testing/selftests/iommu/iommufd.c
@@ -360,9 +360,9 @@ TEST_F(iommufd_ioas, alloc_hwpt_nested)
EXPECT_ERRNO(EBUSY,
_test_ioctl_destroy(self->fd, parent_hwpt_id));

- /* hwpt_invalidate only supports a user-managed hwpt (nested) */
+ /* hwpt_invalidate does not support a parent hwpt */
num_inv = 1;
- test_err_hwpt_invalidate(ENOENT, parent_hwpt_id, inv_reqs,
+ test_err_hwpt_invalidate(EINVAL, parent_hwpt_id, inv_reqs,
IOMMU_HWPT_INVALIDATE_DATA_SELFTEST,
sizeof(*inv_reqs), &num_inv);
assert(!num_inv);
--
2.43.0