Re: [PATCH v26 06/17] vfio: Add migration state change notifier

[Cornelia Huck]

On Mon, 19 Oct 2020 11:57:47 -0600
Alex Williamson <alex.williamson@redhat.com> wrote:

> On Sun, 18 Oct 2020 02:05:03 +0530
> Kirti Wankhede <kwankhede@nvidia.com> wrote:
> 
> > On 9/26/2020 1:50 AM, Alex Williamson wrote:  
> > > On Wed, 23 Sep 2020 04:54:08 +0530
> > > Kirti Wankhede <kwankhede@nvidia.com> wrote:

> > >> diff --git a/include/hw/vfio/vfio-common.h 
> > >> b/include/hw/vfio/vfio-common.h
> > >> index 25e3b1a3b90a..49c7c7a0e29a 100644
> > >> --- a/include/hw/vfio/vfio-common.h
> > >> +++ b/include/hw/vfio/vfio-common.h
> > >> @@ -123,6 +123,7 @@ typedef struct VFIODevice {
> > >>       VMChangeStateEntry *vm_state;
> > >>       uint32_t device_state;
> > >>       int vm_running;
> > >> +    Notifier migration_state;    
> > > 
> > > Can this live in VFIOMigration?  Thanks,
> > >     
> > 
> > No, callback vfio_migration_state_notifier() has notifier argument and 
> > to reach its corresponding device structure as below, its should be in 
> > VFIODevice.
> > 
> > VFIODevice *vbasedev = container_of(notifier, VFIODevice, migration_state); 
> >  
> 
> An alternative would be to place migration_state within VFIOMigration,
> along with a pointer back to vbasedev (like we do in VFIORegion) then
> the notifier could use container_of to get the VFIOMigration structure,
> from which we could get to the VFIODevice via the vbasedev pointer.
> This would better compartmentalize the migration related data into a
> single structure.  Thanks,
> 
> Alex

+1, I think having everything in VFIOMigration would be nicer.