HostIOMMUDevice: Store the VFIO/VDPA agent

Store the agent device (VFIO or VDPA) in the host IOMMU device.
This will allow easy access to some of its resources.

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

hw/vfio/container.c

@@ -1145,6 +1145,7 @@ static bool hiod_legacy_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
 
     hiod->name = g_strdup(vdev->name);
     hiod->caps.aw_bits = vfio_device_get_aw_bits(vdev);
+    hiod->agent = opaque;
 
     return true;
 }

hw/vfio/iommufd.c

@@ -631,6 +631,8 @@ static bool hiod_iommufd_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
         struct iommu_hw_info_vtd vtd;
     } data;
 
+    hiod->agent = opaque;
+
     if (!iommufd_backend_get_device_info(vdev->iommufd, vdev->devid,
                                          &type, &data, sizeof(data), errp)) {
         return false;

include/sysemu/host_iommu_device.h

@@ -34,6 +34,7 @@ struct HostIOMMUDevice {
     Object parent_obj;
 
     char *name;
+    void *agent; /* pointer to agent device, ie. VFIO or VDPA device */
     HostIOMMUDeviceCaps caps;
 };