[PATCH v2 4/4] iommufd/selftest: Add coverage for vdevice tombstone

[Xu Yilun <yilun.xu@linux.intel.com>]

This tests the flow to tombstone vdevice when idevice is to be unbound
before vdevice destroy. The expected result is:

 - idevice unbound tombstones vdevice ID, the ID can't be repurposed
   anymore.
 - Even ioctl(IOMMU_DESTROY) can't free it the tombstoned ID.
 - iommufd_fops_release() can still free everything.

Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>
---
 tools/testing/selftests/iommu/iommufd.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/tools/testing/selftests/iommu/iommufd.c b/tools/testing/selftests/iommu/iommufd.c
index 1a8e85afe9aa..092e1344447e 100644
--- a/tools/testing/selftests/iommu/iommufd.c
+++ b/tools/testing/selftests/iommu/iommufd.c
@@ -3014,6 +3014,19 @@ TEST_F(iommufd_viommu, vdevice_cache)
 	}
 }
 
+TEST_F(iommufd_viommu, vdevice_tombstone)
+{
+	uint32_t viommu_id = self->viommu_id;
+	uint32_t dev_id = self->device_id;
+	uint32_t vdev_id = 0;
+
+	if (dev_id) {
+		test_cmd_vdevice_alloc(viommu_id, dev_id, 0x99, &vdev_id);
+		test_ioctl_destroy(self->stdev_id);
+		EXPECT_ERRNO(ENOENT, _test_ioctl_destroy(self->fd, vdev_id));
+	}
+}
+
 FIXTURE(iommufd_device_pasid)
 {
 	int fd;
-- 
2.25.1