Re: [PATCH V4 05/18] iommu/ioasid: Redefine IOASID set and allocation APIs

From: Jason Gunthorpe
Date: Fri Apr 16 2021 - 13:54:44 EST


On Fri, Apr 16, 2021 at 10:23:32AM -0700, Jacob Pan wrote:

> Perhaps similar to cgroup v1 vs v2, it took a long time and with known
> limitations in v1.

cgroup v2 is still having transition problems, if anything it is a
cautionary tale to think really hard about uAPI because transitioning
can be really hard.

It might be very wise to make /dev/ioasid and /dev/vfio ioctl
compatible in some way so existing software has a smoother upgrade
path.

For instance by defining a default IOASID

Jason