On Tue, Feb 07, 2023 at 12:32:50AM +0000, Tian, Kevin wrote: > > From: Jason Gunthorpe <jgg@xxxxxxxxxx> > > Sent: Monday, February 6, 2023 9:25 PM > > > > On Mon, Feb 06, 2023 at 06:57:35AM +0000, Tian, Kevin wrote: > > > > From: Jason Gunthorpe <jgg@xxxxxxxxxx> > > > > Sent: Friday, February 3, 2023 11:03 PM > > > > > > > > On Fri, Feb 03, 2023 at 08:26:44AM +0000, Tian, Kevin wrote: > > > > > > From: Nicolin Chen <nicolinc@xxxxxxxxxx> > > > > > > Sent: Thursday, February 2, 2023 3:05 PM > > > > > > > > > > > > All drivers are already required to support changing between active > > > > > > UNMANAGED domains when using their attach_dev ops. > > > > > > > > > > All drivers which don't have *broken* UNMANAGED domain? > > > > > > > > No, all drivers.. It has always been used by VFIO. > > > > > > existing iommu_attach_group() doesn't support changing between > > > two UNMANAGED domains. only from default->unmanaged or > > > blocking->unmanaged. > > > > Yes, but before we added the blocking domains VFIO was changing > > between unmanaged domains. Blocking domains are so new that no driver > > could have suddenly started to depend on this. > > In legacy VFIO unmanaged domain was 1:1 associated with vfio > container. I didn't say how a group can switch between two > containers w/o going through transition to/from the default > domain, i.e. detach from 1st container and then attach to the 2nd. Yes, in the past we went through the default domain which is basically another unmanaged domain type. So unmanaged -> unmanaged is OK. > > Inside the driver, it can keep track of the domain pointer if > > attach_dev succeeds > > Are you referring to no error unwinding in __iommu_group_for_each_dev() > so if it is failed some devices may have attach_dev succeeds then simply > recovering group->domain in __iommu_attach_group() is insufficient? Yes Jason
