IOMMUFDDevice represents a device in iommufd and can be used as
a communication interface between devices (i.e., VFIO, VDPA) and
vIOMMU.

Currently it includes only public iommufd handle and device id
which could be used by vIOMMU to get hw IOMMU information.

There will also be some elements in private field in future,
i.e., capability bits for dirty tracking; when nested translation
is supported in future, vIOMMU is going to have more iommufd related
operations like allocate hwpt for a device, attach/detach hwpt, etc.
So IOMMUFDDevice will be further extended with those needs.

IOMMUFDDevice is willingly not a QOM object because we don't want
it to be visible from the user interface.

Introduce a helper iommufd_device_init to initialize IOMMUFDDevice.

Originally-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
---
 include/sysemu/iommufd.h | 14 ++++++++++++++
 backends/iommufd.c       |  6 ++++++
 2 files changed, 20 insertions(+)

diff --git a/include/sysemu/iommufd.h b/include/sysemu/iommufd.h
index 9af27ebd6c..c3f3469760 100644
--- a/include/sysemu/iommufd.h
+++ b/include/sysemu/iommufd.h
@@ -4,6 +4,7 @@
 #include "qom/object.h"
 #include "exec/hwaddr.h"
 #include "exec/cpu-common.h"
+#include "sysemu/host_iommu_device.h"
 
 #define TYPE_IOMMUFD_BACKEND "iommufd"
 OBJECT_DECLARE_TYPE(IOMMUFDBackend, IOMMUFDBackendClass, IOMMUFD_BACKEND)
@@ -33,4 +34,17 @@ int iommufd_backend_map_dma(IOMMUFDBackend *be, uint32_t ioas_id, hwaddr iova,
                             ram_addr_t size, void *vaddr, bool readonly);
 int iommufd_backend_unmap_dma(IOMMUFDBackend *be, uint32_t ioas_id,
                               hwaddr iova, ram_addr_t size);
+
+
+/* Abstraction of host IOMMUFD device */
+typedef struct IOMMUFDDevice {
+    HostIOMMUDevice base;
+    /* private: */
+
+    /* public: */
+    IOMMUFDBackend *iommufd;
+    uint32_t devid;
+} IOMMUFDDevice;
+
+void iommufd_device_init(IOMMUFDDevice *idev);
 #endif
diff --git a/backends/iommufd.c b/backends/iommufd.c
index 1ef683c7b0..d92791bba9 100644
--- a/backends/iommufd.c
+++ b/backends/iommufd.c
@@ -231,3 +231,9 @@ static void register_types(void)
 }
 
 type_init(register_types);
+
+void iommufd_device_init(IOMMUFDDevice *idev)
+{
+    host_iommu_base_device_init(&idev->base, HID_IOMMUFD,
+                                sizeof(IOMMUFDDevice));
+}
-- 
2.34.1