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

["Cédric Le Goater" <clg@redhat.com>]

On 10/3/23 12:14, Eric Auger wrote:
> 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>
> ---
>   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);