Re: [PATCH v3 13/15] vfio/common: Store the parent container in VFIODevice

[Cédric Le Goater]

On 10/3/23 12:14, Eric Auger wrote:

From: Zhenzhong Duan <zhenzhong.d...@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.au...@redhat.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.d...@intel.com>
---
  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;
+    }

Can this happen ? Should it be an assert ?

Thanks,

C.

+
      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);