vfio: selftests: Centralize IOMMU mode name definitions

Replace scattered string literals with MODE_* macros in iommu.h. This
provides a single source of truth for IOMMU mode name strings.

Signed-off-by: Alex Mastro <amastro@fb.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Tested-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20260114-map-mmio-test-v3-1-44e036d95e64@fb.com
Signed-off-by: Alex Williamson <alex@shazbot.org>

Author: Alex Mastro

tools/testing/selftests/vfio/lib/include/libvfio/iommu.h

@@ -61,6 +61,12 @@ iova_t iommu_hva2iova(struct iommu *iommu, void *vaddr);
 
 struct iommu_iova_range *iommu_iova_ranges(struct iommu *iommu, u32 *nranges);
 
+#define MODE_VFIO_TYPE1_IOMMU "vfio_type1_iommu"
+#define MODE_VFIO_TYPE1V2_IOMMU "vfio_type1v2_iommu"
+#define MODE_IOMMUFD_COMPAT_TYPE1 "iommufd_compat_type1"
+#define MODE_IOMMUFD_COMPAT_TYPE1V2 "iommufd_compat_type1v2"
+#define MODE_IOMMUFD "iommufd"
+
 /*
  * Generator for VFIO selftests fixture variants that replicate across all
  * possible IOMMU modes. Tests must define FIXTURE_VARIANT_ADD_IOMMU_MODE()

tools/testing/selftests/vfio/lib/iommu.c

@@ -20,32 +20,32 @@
 #include "../../../kselftest.h"
 #include <libvfio.h>
 
-const char *default_iommu_mode = "iommufd";
+const char *default_iommu_mode = MODE_IOMMUFD;
 
 /* Reminder: Keep in sync with FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(). */
 static const struct iommu_mode iommu_modes[] = {
 	{
-		.name = "vfio_type1_iommu",
+		.name = MODE_VFIO_TYPE1_IOMMU,
 		.container_path = "/dev/vfio/vfio",
 		.iommu_type = VFIO_TYPE1_IOMMU,
 	},
 	{
-		.name = "vfio_type1v2_iommu",
+		.name = MODE_VFIO_TYPE1V2_IOMMU,
 		.container_path = "/dev/vfio/vfio",
 		.iommu_type = VFIO_TYPE1v2_IOMMU,
 	},
 	{
-		.name = "iommufd_compat_type1",
+		.name = MODE_IOMMUFD_COMPAT_TYPE1,
 		.container_path = "/dev/iommu",
 		.iommu_type = VFIO_TYPE1_IOMMU,
 	},
 	{
-		.name = "iommufd_compat_type1v2",
+		.name = MODE_IOMMUFD_COMPAT_TYPE1V2,
 		.container_path = "/dev/iommu",
 		.iommu_type = VFIO_TYPE1v2_IOMMU,
 	},
 	{
-		.name = "iommufd",
+		.name = MODE_IOMMUFD,
 	},
 };
 

tools/testing/selftests/vfio/vfio_dma_mapping_test.c

@@ -165,7 +165,7 @@ TEST_F(vfio_dma_mapping_test, dma_map_unmap)
 	 * IOMMUFD compatibility-mode does not support huge mappings when
 	 * using VFIO_TYPE1_IOMMU.
 	 */
-	if (!strcmp(variant->iommu_mode, "iommufd_compat_type1"))
+	if (!strcmp(variant->iommu_mode, MODE_IOMMUFD_COMPAT_TYPE1))
 		mapping_size = SZ_4K;
 
 	ASSERT_EQ(0, rc);