Hi Tejun, On Wed, 3 Mar 2021 10:44:28 -0500, Tejun Heo <tj@xxxxxxxxxx> wrote: > On Sat, Feb 27, 2021 at 02:01:23PM -0800, Jacob Pan wrote: > > IOASIDs are used to associate DMA requests with virtual address spaces. > > They are a system-wide limited resource made available to the userspace > > applications. Let it be VMs or user-space device drivers. > > > > This RFC patch introduces a cgroup controller to address the following > > problems: > > 1. Some user applications exhaust all the available IOASIDs thus > > depriving others of the same host. > > 2. System admins need to provision VMs based on their needs for IOASIDs, > > e.g. the number of VMs with assigned devices that perform DMA requests > > with PASID. > > Please take a look at the proposed misc controller: > > http://lkml.kernel.org/r/20210302081705.1990283-2-vipinsh@xxxxxxxxxx > > Would that fit your bill? The interface definitely can be reused. But IOASID has a different behavior in terms of migration and ownership checking. I guess SEV key IDs are not tied to a process whereas IOASIDs are. Perhaps this can be solved by adding + .can_attach = ioasids_can_attach, + .cancel_attach = ioasids_cancel_attach, Let me give it a try and come back. Thanks for the pointer. Jacob > > Thanks. > Thanks, Jacob
