> But the helpers seem to be generic. They take "task" as a parameter and > handle the task as non-current case. So the helpers are not for PASID only. > They may be used by others to modify a running task's FPU state. But > It's not safe to do so. > > At least need some comments/restriction for the helpers to be used on > a running task?
Fenghua, Correct. When I add some comments I'll make it very clear that it is the responsibility of the caller to make sure that the task that is targeted cannot run. Earlier in this thread Dave suggested there are two cases where these helpers might be useful: 1) Fork/clone - to set up some xsave state in the child ... but this would be done before the child is allowed to run. 2) ptrace - this is a "maybe" because ptrace already has code to handle all the xsave state as a single entity. Perhaps someone might want to change it to only modify a single feature ... but this seems unlikely. In any case the ptrace code already "stops" the target process while it is reading/writing state. -Tony _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu