diff --git a/tools/testing/selftests/iommu/iommufd_utils.h b/tools/testing/selftests/iommu/iommufd_utils.h
index 72f6636e5d90..a5d4cbd089ba 100644
--- a/tools/testing/selftests/iommu/iommufd_utils.h
+++ b/tools/testing/selftests/iommu/iommufd_utils.h
@@ -897,7 +897,8 @@ static int _test_cmd_trigger_iopf(int fd, __u32 device_id, __u32 pasid,
 					    pasid, fault_fd))
 
 static int _test_cmd_viommu_alloc(int fd, __u32 device_id, __u32 hwpt_id,
-				  __u32 type, __u32 flags, __u32 *viommu_id)
+				  __u32 flags, __u32 type, void *data,
+				  __u32 data_len, __u32 *viommu_id)
 {
 	struct iommu_viommu_alloc cmd = {
 		.size = sizeof(cmd),
@@ -905,6 +906,8 @@ static int _test_cmd_viommu_alloc(int fd, __u32 device_id, __u32 hwpt_id,
 		.type = type,
 		.dev_id = device_id,
 		.hwpt_id = hwpt_id,
+		.data_uptr = (uint64_t)data,
+		.data_len = data_len,
 	};
 	int ret;
 
@@ -916,13 +919,15 @@ static int _test_cmd_viommu_alloc(int fd, __u32 device_id, __u32 hwpt_id,
 	return 0;
 }
 
-#define test_cmd_viommu_alloc(device_id, hwpt_id, type, viommu_id)        \
-	ASSERT_EQ(0, _test_cmd_viommu_alloc(self->fd, device_id, hwpt_id, \
-					    type, 0, viommu_id))
-#define test_err_viommu_alloc(_errno, device_id, hwpt_id, type, viommu_id) \
-	EXPECT_ERRNO(_errno,                                               \
-		     _test_cmd_viommu_alloc(self->fd, device_id, hwpt_id,  \
-					    type, 0, viommu_id))
+#define test_cmd_viommu_alloc(device_id, hwpt_id, type, data, data_len,      \
+			      viommu_id)                                     \
+	ASSERT_EQ(0, _test_cmd_viommu_alloc(self->fd, device_id, hwpt_id, 0, \
+					    type, data, data_len, viommu_id))
+#define test_err_viommu_alloc(_errno, device_id, hwpt_id, type, data,        \
+			      data_len, viommu_id)                           \
+	EXPECT_ERRNO(_errno,                                                 \
+		     _test_cmd_viommu_alloc(self->fd, device_id, hwpt_id, 0, \
+					    type, data, data_len, viommu_id))
 
 static int _test_cmd_vdevice_alloc(int fd, __u32 viommu_id, __u32 idev_id,
 				   __u64 virt_id, __u32 *vdev_id)
diff --git a/tools/testing/selftests/iommu/iommufd.c b/tools/testing/selftests/iommu/iommufd.c
index 1a8e85afe9aa..f22388dfacad 100644
--- a/tools/testing/selftests/iommu/iommufd.c
+++ b/tools/testing/selftests/iommu/iommufd.c
@@ -2688,7 +2688,7 @@ FIXTURE_SETUP(iommufd_viommu)
 
 		/* Allocate a vIOMMU taking refcount of the parent hwpt */
 		test_cmd_viommu_alloc(self->device_id, self->hwpt_id,
-				      IOMMU_VIOMMU_TYPE_SELFTEST,
+				      IOMMU_VIOMMU_TYPE_SELFTEST, NULL, 0,
 				      &self->viommu_id);
 
 		/* Allocate a regular nested hwpt */
@@ -2727,24 +2727,27 @@ TEST_F(iommufd_viommu, viommu_negative_tests)
 	if (self->device_id) {
 		/* Negative test -- invalid hwpt (hwpt_id=0) */
 		test_err_viommu_alloc(ENOENT, device_id, 0,
-				      IOMMU_VIOMMU_TYPE_SELFTEST, NULL);
+				      IOMMU_VIOMMU_TYPE_SELFTEST, NULL, 0,
+				      NULL);
 
 		/* Negative test -- not a nesting parent hwpt */
 		test_cmd_hwpt_alloc(device_id, ioas_id, 0, &hwpt_id);
 		test_err_viommu_alloc(EINVAL, device_id, hwpt_id,
-				      IOMMU_VIOMMU_TYPE_SELFTEST, NULL);
+				      IOMMU_VIOMMU_TYPE_SELFTEST, NULL, 0,
+				      NULL);
 		test_ioctl_destroy(hwpt_id);
 
 		/* Negative test -- unsupported viommu type */
 		test_err_viommu_alloc(EOPNOTSUPP, device_id, self->hwpt_id,
-				      0xdead, NULL);
+				      0xdead, NULL, 0, NULL);
 		EXPECT_ERRNO(EBUSY,
 			     _test_ioctl_destroy(self->fd, self->hwpt_id));
 		EXPECT_ERRNO(EBUSY,
 			     _test_ioctl_destroy(self->fd, self->viommu_id));
 	} else {
 		test_err_viommu_alloc(ENOENT, self->device_id, self->hwpt_id,
-				      IOMMU_VIOMMU_TYPE_SELFTEST, NULL);
+				      IOMMU_VIOMMU_TYPE_SELFTEST, NULL, 0,
+				      NULL);
 	}
 }
 
@@ -2791,6 +2794,20 @@ TEST_F(iommufd_viommu, viommu_alloc_nested_iopf)
 	}
 }
 
+TEST_F(iommufd_viommu, viommu_alloc_with_data)
+{
+	struct iommu_viommu_selftest data = {
+		.in_data = 0xbeef,
+	};
+
+	if (self->device_id) {
+		test_cmd_viommu_alloc(self->device_id, self->hwpt_id,
+				      IOMMU_VIOMMU_TYPE_SELFTEST, &data,
+				      sizeof(data), &self->viommu_id);
+		ASSERT_EQ(data.out_data, data.in_data);
+	}
+}
+
 TEST_F(iommufd_viommu, vdevice_alloc)
 {
 	uint32_t viommu_id = self->viommu_id;
@@ -3105,8 +3122,7 @@ TEST_F(iommufd_device_pasid, pasid_attach)
 
 	/* Allocate a regular nested hwpt based on viommu */
 	test_cmd_viommu_alloc(self->device_id, parent_hwpt_id,
-			      IOMMU_VIOMMU_TYPE_SELFTEST,
-			      &viommu_id);
+			      IOMMU_VIOMMU_TYPE_SELFTEST, NULL, 0, &viommu_id);
 	test_cmd_hwpt_alloc_nested(self->device_id, viommu_id,
 				   IOMMU_HWPT_ALLOC_PASID,
 				   &nested_hwpt_id[2],
diff --git a/tools/testing/selftests/iommu/iommufd_fail_nth.c b/tools/testing/selftests/iommu/iommufd_fail_nth.c
index e11ec4b121fc..f7ccf1822108 100644
--- a/tools/testing/selftests/iommu/iommufd_fail_nth.c
+++ b/tools/testing/selftests/iommu/iommufd_fail_nth.c
@@ -688,8 +688,9 @@ TEST_FAIL_NTH(basic_fail_nth, device)
 				 IOMMU_HWPT_DATA_NONE, 0, 0))
 		return -1;
 
-	if (_test_cmd_viommu_alloc(self->fd, idev_id, hwpt_id,
-				   IOMMU_VIOMMU_TYPE_SELFTEST, 0, &viommu_id))
+	if (_test_cmd_viommu_alloc(self->fd, idev_id, hwpt_id, 0,
+				   IOMMU_VIOMMU_TYPE_SELFTEST, NULL, 0,
+				   &viommu_id))
 		return -1;
 
 	if (_test_cmd_vdevice_alloc(self->fd, viommu_id, idev_id, 0, &vdev_id))
