Re: [v7 0/3] plumb kvm/vfio to notify kvm:group attach/detach

[Alex Williamson <alex.williamson@redhat.com>]

On Tue, 29 Nov 2016 11:02:02 +0800
Jike Song <jike.song@intel.com> wrote:

> On 11/22/2016 02:09 PM, Jike Song wrote:
> > So far KVM and VFIO are mostly transparent to each other.
> > However, there are users who would rely on them both. For
> > example, KVMGT relies on VFIO to mediate device operations,
> > and it also relies on KVM for features such as guest page
> > tracking. To do that, it needs to know which KVM instance
> > a vfio_group is attached to, when it will be detached.
> > 
> > There is already a kvm_vfio device serving for similar
> > purpose, this series extends it to allow users register
> > notifiers on a vfio_group, and notify kvm:group attaching
> > and detaching events to that.
> > 
> > 
> > Changes v7:
> > 	- replace vfio->opened with container user like iommu notifier registration
> > 	- fix a typo
> > Changes v6:
> > 	- only allow registration on already opened vfio_group 
> > 	- moved WARN_ON from vfio_group_release to vfio_group_fops_release
> > 	- remove unnecessary check
> > Changes v5:
> > 	- separate vfio_group and vfio_iommu events from each other
> > 	- force user to specify which type it is interested in, and which events.
> > 	  Register it IFF all required events are supported
> > Changes v4:
> > 	- use a notifier-based implementation in vfio_group
> > 	- combine the notifier along with iommu notifier by Kirti
> > Changes v3:
> > 	- don't touch kvm_put_kvm, vfio won't need it
> > 	- fix a race condition
> > Changes v2:
> > 	- As Paolo suggested, drop the type and get/put ops from
> > 	  vfio, assuming that the data will always be kvm.
> > 
> > 
> > 
> > Jike Song (3):
> >   vfio: vfio_register_notifier: classify iommu notifier
> >   vfio: support notifier chain in vfio_group
> >   kvm: set/clear kvm to/from vfio_group when group add/delete
> > 
> >  drivers/vfio/vfio.c  | 167 ++++++++++++++++++++++++++++++++++++++++++++-------
> >  include/linux/vfio.h |  22 ++++++-
> >  virt/kvm/vfio.c      |  31 ++++++++++
> >  3 files changed, 195 insertions(+), 25 deletions(-)  
> 
> Hi Alex,
> 
> Since Paolo has ACKed a previous version of PATCH [3/3] before, if you have
> no more comments on this series, could you pick them up? Please be aware that
> 1/3 was updated, or I can send a v8 if you prefer :)

Sorry for the delay, I was on holiday.  Please send a v8, particularly
since I noted updates in patch 3/3 as well.  I would prefer to commit
this with a R-b from Kirti since the NVIDIA driver is also affected by
this, but I believe this is the right approach for us long term.  I'm
also having trouble finding an ack from Paolo that's particularly
relevant for the kvm-vfio portion, but I don't think this is a
controversial issue, I feel comfortable that he's onboard with the
idea.  Thanks,

Alex