On Mon, Jun 28, 2021 at 06:45:23AM +0000, Tian, Kevin wrote: > 7) Unbinding detaches the device from the block_dma domain and > re-attach it to the default domain. From now on the user should > be denied from accessing the device. vfio should tear down the > MMIO mapping at this point. I think we should just forbid this, so long as the device_fd is open the iommu_fd cannot be destroyed and there is no way to detact a device other than closing its Fd. revoke is tricky enough to implement we should avoid it. > It's still an open whether we want to further allow devices within a group > attached to different IOASIDs in case that the source devices are reliably > identifiable. This is an usage not supported by existing vfio and might be > not worthwhile due to improved isolation over time. The main decision here is to decide if the uAPI should have some way to indicate that a device does not have its own unique IOASID but is sharing with the group Jason
