[PATCH v5 13/15] vfio/common: Store the parent container in VFIODevice

[Eric Auger <eric.auger@redhat.com>]

From: Zhenzhong Duan <zhenzhong.duan@intel.com>

let's store the parent contaienr within the VFIODevice.
This simplifies the logic in vfio_viommu_preset() and
brings the benefice to hide the group specificity which
is useful for IOMMUFD migration.

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

---
v4 -> v5:
- restore check on !vbasedev->container!

v3 -> v4:
- Dropped check on !vbasedev->container
---
 include/hw/vfio/vfio-common.h | 1 +
 hw/vfio/common.c              | 8 +++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 8ca70dd821..bf12e40667 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -132,6 +132,7 @@ typedef struct VFIODevice {
     QLIST_ENTRY(VFIODevice) next;
     QLIST_ENTRY(VFIODevice) container_next;
     struct VFIOGroup *group;
+    VFIOContainer *container;
     char *sysfsdev;
     char *name;
     DeviceState *dev;
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index ef9dc7c747..55f8a113ea 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -184,7 +184,7 @@ void vfio_unblock_multiple_devices_migration(void)
 
 bool vfio_viommu_preset(VFIODevice *vbasedev)
 {
-    return vbasedev->group->container->space->as != &address_space_memory;
+    return vbasedev->container->space->as != &address_space_memory;
 }
 
 static void vfio_set_migration_error(int err)
@@ -2655,6 +2655,7 @@ int vfio_attach_device(char *name, VFIODevice *vbasedev,
     }
 
     container = group->container;
+    vbasedev->container = container;
     QLIST_INSERT_HEAD(&container->device_list, vbasedev, container_next);
 
     return ret;
@@ -2664,7 +2665,12 @@ void vfio_detach_device(VFIODevice *vbasedev)
 {
     VFIOGroup *group = vbasedev->group;
 
+    if (!vbasedev->container) {
+        return;
+    }
+
     QLIST_REMOVE(vbasedev, container_next);
+    vbasedev->container = NULL;
     trace_vfio_detach_device(vbasedev->name, group->groupid);
     vfio_put_base_device(vbasedev);
     vfio_put_group(group);
-- 
2.41.0