Beyond rings 0 and 3


#1

Though most general-use operating systems use only rings 0 and 3, there are many other that use rings 1 and 2 as well. An example is IBM’s OS/2 Warp. It uses ring 2 for certain device drivers rather than ring 0 so that if they crash, they won’t impact the kernel. This seems like a good idea! With that, it seems KVM needs to be able to support the additional privilege rings on the Intel/AMD processors.

Is there anybody out there that has done any work adding this capability to KVM?