[PULL 17/28] vfio: add vfio_attach_device_by_iommu_type()

["Cédric Le Goater" <clg@redhat.com>]

From: John Levon <john.levon@nutanix.com>

Allow attachment by explicitly passing a TYPE_VFIO_IOMMU_* string;
vfio-user will use this later.

Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: John Levon <john.levon@nutanix.com>
Link: https://lore.kernel.org/qemu-devel/20250507152020.1254632-4-john.levon@nutanix.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 include/hw/vfio/vfio-device.h |  3 +++
 hw/vfio/device.c              | 22 +++++++++++++++-------
 2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/include/hw/vfio/vfio-device.h b/include/hw/vfio/vfio-device.h
index 342c4ba3bfec8d143a297203dbfa0e6f6fae3535..8b1437ba6654d08f65740f42dc3a50775d7f5cc1 100644
--- a/include/hw/vfio/vfio-device.h
+++ b/include/hw/vfio/vfio-device.h
@@ -127,6 +127,9 @@ bool vfio_device_hiod_create_and_realize(VFIODevice *vbasedev,
                                          const char *typename, Error **errp);
 bool vfio_device_attach(char *name, VFIODevice *vbasedev,
                         AddressSpace *as, Error **errp);
+bool vfio_device_attach_by_iommu_type(const char *iommu_type, char *name,
+                                      VFIODevice *vbasedev, AddressSpace *as,
+                                      Error **errp);
 void vfio_device_detach(VFIODevice *vbasedev);
 VFIODevice *vfio_get_vfio_device(Object *obj);
 
diff --git a/hw/vfio/device.c b/hw/vfio/device.c
index 31c441a3dfffdf459994407904ab78b1798bf979..9673b0717ead435e117d8084720fde4ba3a13dd8 100644
--- a/hw/vfio/device.c
+++ b/hw/vfio/device.c
@@ -376,21 +376,29 @@ VFIODevice *vfio_get_vfio_device(Object *obj)
     }
 }
 
-bool vfio_device_attach(char *name, VFIODevice *vbasedev,
-                        AddressSpace *as, Error **errp)
+bool vfio_device_attach_by_iommu_type(const char *iommu_type, char *name,
+                                      VFIODevice *vbasedev, AddressSpace *as,
+                                      Error **errp)
 {
     const VFIOIOMMUClass *ops =
-        VFIO_IOMMU_CLASS(object_class_by_name(TYPE_VFIO_IOMMU_LEGACY));
-
-    if (vbasedev->iommufd) {
-        ops = VFIO_IOMMU_CLASS(object_class_by_name(TYPE_VFIO_IOMMU_IOMMUFD));
-    }
+        VFIO_IOMMU_CLASS(object_class_by_name(iommu_type));
 
     assert(ops);
 
     return ops->attach_device(name, vbasedev, as, errp);
 }
 
+bool vfio_device_attach(char *name, VFIODevice *vbasedev,
+                        AddressSpace *as, Error **errp)
+{
+    const char *iommu_type = vbasedev->iommufd ?
+                             TYPE_VFIO_IOMMU_IOMMUFD :
+                             TYPE_VFIO_IOMMU_LEGACY;
+
+    return vfio_device_attach_by_iommu_type(iommu_type, name, vbasedev,
+                                            as, errp);
+}
+
 void vfio_device_detach(VFIODevice *vbasedev)
 {
     if (!vbasedev->bcontainer) {
-- 
2.49.0