[PATCH for-9.0 v2 04/10] vfio/container: Introduce a VFIOIOMMU QOM interface

["Cédric Le Goater" <clg@redhat.com>]

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>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 v2: - Removed superfluous define and struct definitions
     - Improved comments and commit log
     
 include/hw/vfio/vfio-container-base.h | 23 +++++++++++++++++++----
 hw/vfio/common.c                      |  2 +-
 hw/vfio/container-base.c              | 12 +++++++++++-
 hw/vfio/pci.c                         |  2 +-
 4 files changed, 32 insertions(+), 7 deletions(-)

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 1874ec1aba987cac6cb83f86650e7a5e1968c327..d84a9e73a65de4e4c1cdaf65619a700bd8d6b802 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);
 }
-- 
2.43.0