iommufd: Allow hwpt_id to carry viommu_id for IOMMU_HWPT_INVALIDATE

With a vIOMMU object, use space can flush any IOMMU related cache that can
be directed via a vIOMMU object. It is similar to the IOMMU_HWPT_INVALIDATE
uAPI, but can cover a wider range than IOTLB, e.g. device/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. Drivers
can define different structures for vIOMMU invalidations v.s. HWPT ones.

Since both the HWPT-based and vIOMMU-based invalidation pathways check own
cache invalidation op, remove the WARN_ON_ONCE in the allocator.

Update the uAPI, kdoc, and selftest case accordingly.

Link: https://patch.msgid.link/r/b411e2245e303b8a964f39f49453a5dff280968f.1730836308.git.nicolinc@nvidia.com
Reviewed-by: Jason Gunthorpe <[email protected]>
Reviewed-by: Kevin Tian <[email protected]>
Signed-off-by: Nicolin Chen <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>

Author: nicolinc

drivers/iommu/iommufd/hw_pagetable.c

@@ -251,8 +251,7 @@ iommufd_hwpt_nested_alloc(struct iommufd_ctx *ictx,
 	}
 	hwpt->domain->owner = ops;
 
-	if (WARN_ON_ONCE(hwpt->domain->type != IOMMU_DOMAIN_NESTED ||
-			 !hwpt->domain->ops->cache_invalidate_user)) {
+	if (WARN_ON_ONCE(hwpt->domain->type != IOMMU_DOMAIN_NESTED)) {
 		rc = -EINVAL;
 		goto out_abort;
 	}
@@ -483,7 +482,7 @@ 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;
 
@@ -497,17 +496,40 @@ 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);
+
+		if (!hwpt->domain->ops ||
+		    !hwpt->domain->ops->cache_invalidate_user) {
+			rc = -EOPNOTSUPP;
+			goto out_put_pt;
+		}
+		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)))

include/uapi/linux/iommufd.h

@@ -700,7 +700,7 @@ 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 a 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
@@ -711,8 +711,11 @@ 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.
  *

tools/testing/selftests/iommu/iommufd.c

@@ -367,9 +367,9 @@ 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);