Re: About the instance_finalize callback in VFIO PCI

[Cédric Le Goater]

On 3/20/23 10:31, Yang Zhong wrote:
> Hello Alex and Paolo,
>
> There is one instance_finalize callback definition in hw/vfio/pci.c, but
> i find this callback(vfio_instance_finalize()) never be called during the
> VM shutdown with close VM or "init 0" command in guest.
>
> The Qemu related command:
>     ......
>     -device vfio-pci,host=d9:00.0
>     ......

well, the finalize op is correctly called for hot unplugged devices, using
device_add.

> static const TypeInfo vfio_pci_dev_info = {
>      .name = TYPE_VFIO_PCI,
>      .parent = TYPE_PCI_DEVICE,
>      .instance_size = sizeof(VFIOPCIDevice),
>      .class_init = vfio_pci_dev_class_init,
>      .instance_init = vfio_instance_init,
>      .instance_finalize = vfio_instance_finalize,
>      .interfaces = (InterfaceInfo[]) {
>          { INTERFACE_PCIE_DEVICE },
>          { INTERFACE_CONVENTIONAL_PCI_DEVICE },
>          { }
>      },
> };
>
> If my test method is wrong, would you please tell me how to trigger to
> this callback when VM shutdown? thanks

I would have thought that user_creatable_cleanup would have taken care
of it. But it's not. This needs some digging.

C.

 
> By the way, i also debugged other instance_finalize callback functions,
> if my understanding is right, all instance_finalize callback should be
> called from object_unref(object) from qemu_cleanup(void) in
> ./softmmu/runstate.c. But there is no VFIO related object_unref() call in
> this cleanup function, So the instance_finalize callback in vfio pci
> should be useless? thanks!
>
> Regards,
> Yang