> From: Kenneth Lee > Sent: Thursday, August 2, 2018 12:16 PM > > On Thu, Aug 02, 2018 at 03:17:03AM +0000, Tian, Kevin wrote: > > > From: Kenneth Lee > > > Sent: Wednesday, August 1, 2018 6:22 PM > > > > > > From: Kenneth Lee <liguozhu@xxxxxxxxxxxxx> > > > > > > This patch add sharing interface for a iommu_group. The new interface: > > > > > > iommu_group_share_domain() > > > iommu_group_unshare_domain() > > > > > > can be used by some virtual iommu_group (such as iommu_group for > > > spimdev) > > > to share their parent's iommu_group. > > > > > > When the domain of the group is shared, it cannot be changed before > > > unshared. In the future, notification can be added if update is required. > > > > Is it necessary or just asking VFIO to use parent domain directly? > > > Even we add to VFIO, the iommu still need to be changed. We can move > the type1 > part to VFIO if we have agreement in RFC stage. We have similar consideration in IOMMU aware mdev series. Now we are inclined to avoid faked entity within IOMMU layer - leave to caller to figure out right physical entity for any IOMMU ops. That might be leveraged here too after we get a new version. Thanks Kevin