When __iommu_map() fails (as expected for MMIO in iommufd modes), the
test proceeds to call __iommu_unmap() for cleanup.

The behavior of unmapping a non-existent range differs between iommufd
native and compat modes:
- Native iommufd returns -ENOENT (failure).
- Compat iommufd returns 0 (success), mimicking legacy VFIO behavior.

The previous code asserted that __iommu_unmap() always fails, which
caused test failures in compat mode. Fix this by checking the return
value based on the iommufd mode.

Signed-off-by: Yi Lai <yi1.lai@intel.com>
---
 .../testing/selftests/vfio/vfio_dma_mapping_mmio_test.c  | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/vfio/vfio_dma_mapping_mmio_test.c b/tools/testing/selftests/vfio/vfio_dma_mapping_mmio_test.c
index 4f7ecdca0215..e6a2b2ff91f0 100644
--- a/tools/testing/selftests/vfio/vfio_dma_mapping_mmio_test.c
+++ b/tools/testing/selftests/vfio/vfio_dma_mapping_mmio_test.c
@@ -101,7 +101,14 @@ static void do_mmio_map_test(struct iommu *iommu,
 		iommu_unmap(iommu, &region);
 	} else {
 		VFIO_ASSERT_NE(__iommu_map(iommu, &region), 0);
-		VFIO_ASSERT_NE(__iommu_unmap(iommu, &region, NULL), 0);
+		/*
+		 * Native IOMMUFD returns -ENOENT and Compat IOMMUFD returns 0
+		 * for unmapping a non-existent range.
+		 */
+		if (!strcmp(iommu->mode->name, MODE_IOMMUFD))
+			VFIO_ASSERT_NE(__iommu_unmap(iommu, &region, NULL), 0);
+		else
+			VFIO_ASSERT_EQ(__iommu_unmap(iommu, &region, NULL), 0);
 	}
 }
 
-- 
2.43.0