vfio/container: Introduce a VFIOIOMMU QOM interface

VFIOContainerBase was not introduced as 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.

Simply transform the VFIOIOMMUOps struct in an InterfaceClass and do
some initial name replacements. Next changes will start converting
VFIOIOMMUOps.

Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Tested-by: Eric Farman <farman@linux.ibm.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>

4 files changed, 32 insertions, 7 deletions

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 08a3e57672..49dab41566 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 1ffd25bbfa..913ae49077 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 9f838978be..d7fe06715c 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);
 }
diff --git a/include/hw/vfio/vfio-container-base.h b/include/hw/vfio/vfio-container-base.h
index 5c9594b6c7..d6147b4aee 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,