vfio/iommufd: Implement HostIOMMUDeviceClass::realize() handler

It calls iommufd_backend_get_device_info() to get host IOMMU
related information and translate it into HostIOMMUDeviceCaps
for query with .get_cap().

For aw_bits, use the same way as legacy backend by calling
vfio_device_get_aw_bits() which is common for different vendor
IOMMU.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

hw/vfio/iommufd.c

@@ -619,6 +619,35 @@ static void vfio_iommu_iommufd_class_init(ObjectClass *klass, void *data)
     vioc->pci_hot_reset = iommufd_cdev_pci_hot_reset;
 };
 
+static bool hiod_iommufd_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
+                                      Error **errp)
+{
+    VFIODevice *vdev = opaque;
+    HostIOMMUDeviceCaps *caps = &hiod->caps;
+    enum iommu_hw_info_type type;
+    union {
+        struct iommu_hw_info_vtd vtd;
+    } data;
+
+    if (!iommufd_backend_get_device_info(vdev->iommufd, vdev->devid,
+                                         &type, &data, sizeof(data), errp)) {
+        return false;
+    }
+
+    hiod->name = g_strdup(vdev->name);
+    caps->type = type;
+    caps->aw_bits = vfio_device_get_aw_bits(vdev);
+
+    return true;
+}
+
+static void hiod_iommufd_vfio_class_init(ObjectClass *oc, void *data)
+{
+    HostIOMMUDeviceClass *hiodc = HOST_IOMMU_DEVICE_CLASS(oc);
+
+    hiodc->realize = hiod_iommufd_vfio_realize;
+};
+
 static const TypeInfo types[] = {
     {
         .name = TYPE_VFIO_IOMMU_IOMMUFD,
@@ -627,6 +656,7 @@ static const TypeInfo types[] = {
     }, {
         .name = TYPE_HOST_IOMMU_DEVICE_IOMMUFD_VFIO,
         .parent = TYPE_HOST_IOMMU_DEVICE_IOMMUFD,
+        .class_init = hiod_iommufd_vfio_class_init,
     }
 };