Re: About the instance_finalize callback in VFIO PCI

[Yang Zhong]

On Wed, Mar 22, 2023 at 01:56:13PM +0100, Cédric Le Goater wrote:
> On 3/22/23 13:28, Yang Zhong wrote:
> > On Tue, Mar 21, 2023 at 06:30:14PM +0100, Cédric Le Goater wrote:
> > > 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.
> > > 
> >     Thanks Cédric, i can use device_del command in the monitor to
> >     trigger this instance_finalize callback function in the VFIO PCI.
> >     thanks!
> 
> yes. I think that in the shutdown case, QEMU simply relies on exit() to
> do the cleanup. On the kernel side, unmaps, fds being closed trigger any
> allocated resources.
> 
> Out of curiosity, what were you trying to achieve in the finalize op ?
> 
 
 We are doing one new feature, which need this callback to do some
 cleanup work with VFIO/iommufd kernel module. thanks!

 Yang


> Thanks,
> 
> C.