iommufd/selftest: Add a selftest for iommufd_device_attach() with a hwpt argument

This can now be covered since we have a full struct device.

Link: https://lore.kernel.org/r/12-v3-ae9c2975a131+2e1e8-iommufd_hwpt_jgg@nvidia.com
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

Author: jgunthorpe

tools/testing/selftests/iommu/iommufd.c

@@ -187,6 +187,7 @@ FIXTURE(iommufd_ioas)
 	int fd;
 	uint32_t ioas_id;
 	uint32_t stdev_id;
+	uint32_t hwpt_id;
 	uint64_t base_iova;
 };
 
@@ -212,7 +213,8 @@ FIXTURE_SETUP(iommufd_ioas)
 	}
 
 	for (i = 0; i != variant->mock_domains; i++) {
-		test_cmd_mock_domain(self->ioas_id, &self->stdev_id, NULL);
+		test_cmd_mock_domain(self->ioas_id, &self->stdev_id,
+				     &self->hwpt_id);
 		self->base_iova = MOCK_APERTURE_START;
 	}
 }
@@ -259,6 +261,16 @@ TEST_F(iommufd_ioas, ioas_destroy)
 	}
 }
 
+TEST_F(iommufd_ioas, hwpt_attach)
+{
+	/* Create a device attached directly to a hwpt */
+	if (self->stdev_id) {
+		test_cmd_mock_domain(self->hwpt_id, NULL, NULL);
+	} else {
+		test_err_mock_domain(ENOENT, self->hwpt_id, NULL, NULL);
+	}
+}
+
 TEST_F(iommufd_ioas, ioas_area_destroy)
 {
 	/* Adding an area does not change ability to destroy */