[PULL,04/17] vfio/container: Introduce a VFIOIOMMU QOM interface

diff --git a/include/hw/vfio/vfio-container-base.h b/include/hw/vfio/vfio-container-base.h
index 5c9594b6c77681e5593236e711e7e391e5f2bdff..d6147b4aeef26b6075c88579108e566720f58ebb 100644
--- a/include/hw/vfio/vfio-container-base.h
+++ b/include/hw/vfio/vfio-container-base.h
@@ -16,7 +16,8 @@ 
 #include "exec/memory.h"
 
 typedef struct VFIODevice VFIODevice;
-typedef struct VFIOIOMMUOps VFIOIOMMUOps;
+typedef struct VFIOIOMMUClass VFIOIOMMUClass;
+#define VFIOIOMMUOps VFIOIOMMUClass /* To remove */
 
 typedef struct {
     unsigned long *bitmap;
@@ -34,7 +35,7 @@  typedef struct VFIOAddressSpace {
  * This is the base object for vfio container backends
  */
 typedef struct VFIOContainerBase {
-    const VFIOIOMMUOps *ops;
+    const VFIOIOMMUClass *ops;
     VFIOAddressSpace *space;
     MemoryListener listener;
     Error *error;
@@ -88,10 +89,24 @@  int vfio_container_query_dirty_bitmap(const VFIOContainerBase *bcontainer,
 
 void vfio_container_init(VFIOContainerBase *bcontainer,
                          VFIOAddressSpace *space,
-                         const VFIOIOMMUOps *ops);
+                         const VFIOIOMMUClass *ops);
 void vfio_container_destroy(VFIOContainerBase *bcontainer);
 
-struct VFIOIOMMUOps {
+
+#define TYPE_VFIO_IOMMU "vfio-iommu"
+
+/*
+ * VFIOContainerBase is not an abstract QOM object because it felt
+ * unnecessary to expose all the IOMMU backends to the QEMU machine
+ * and human interface. However, we can still abstract the IOMMU
+ * backend handlers using a QOM interface class. This provides more
+ * flexibility when referencing the various implementations.
+ */
+DECLARE_CLASS_CHECKERS(VFIOIOMMUClass, VFIO_IOMMU, TYPE_VFIO_IOMMU)
+
+struct VFIOIOMMUClass {
+    InterfaceClass parent_class;
+
     /* basic feature */
     int (*dma_map)(const VFIOContainerBase *bcontainer,
                    hwaddr iova, ram_addr_t size,
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 08a3e576725b1fc9f2f7e425375df3b827c4fe56..49dab41566f07ba7be1100fed1973e028d34467c 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -1503,7 +1503,7 @@  retry:
 int vfio_attach_device(char *name, VFIODevice *vbasedev,
                        AddressSpace *as, Error **errp)
 {
-    const VFIOIOMMUOps *ops = &vfio_legacy_ops;
+    const VFIOIOMMUClass *ops = &vfio_legacy_ops;
 
 #ifdef CONFIG_IOMMUFD
     if (vbasedev->iommufd) {
diff --git a/hw/vfio/container-base.c b/hw/vfio/container-base.c
index 1ffd25bbfa8bd3d404e43b96357273b95f5a0031..913ae49077c4f09b7b27517c1231cfbe4befb7fb 100644
--- a/hw/vfio/container-base.c
+++ b/hw/vfio/container-base.c
@@ -72,7 +72,7 @@  int vfio_container_query_dirty_bitmap(const VFIOContainerBase *bcontainer,
 }
 
 void vfio_container_init(VFIOContainerBase *bcontainer, VFIOAddressSpace *space,
-                         const VFIOIOMMUOps *ops)
+                         const VFIOIOMMUClass *ops)
 {
     bcontainer->ops = ops;
     bcontainer->space = space;
@@ -99,3 +99,13 @@  void vfio_container_destroy(VFIOContainerBase *bcontainer)
 
     g_list_free_full(bcontainer->iova_ranges, g_free);
 }
+
+static const TypeInfo types[] = {
+    {
+        .name = TYPE_VFIO_IOMMU,
+        .parent = TYPE_INTERFACE,
+        .class_size = sizeof(VFIOIOMMUClass),
+    },
+};
+
+DEFINE_TYPES(types)
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 9f838978bea11cacf95b0907c76ac0879a6313bf..d7fe06715c4b9cde66a68c31aaf405315921b0d6 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -2488,7 +2488,7 @@  int vfio_pci_get_pci_hot_reset_info(VFIOPCIDevice *vdev,
 static int vfio_pci_hot_reset(VFIOPCIDevice *vdev, bool single)
 {
     VFIODevice *vbasedev = &vdev->vbasedev;
-    const VFIOIOMMUOps *ops = vbasedev->bcontainer->ops;
+    const VFIOIOMMUClass *ops = vbasedev->bcontainer->ops;
 
     return ops->pci_hot_reset(vbasedev, single);
 }