RFC: Tainting the kernel on raw I/O access

["H. Peter Anvin" <h.peter.anvin@intel.com>]

In a meeting earlier today, we discussed MSR access and that it could be
used to do bad things.  The same applies to other forms of raw I/O
(/dev/mem, /dev/port, ioperm, iopl, etc.)

This is basically the same problem with which the secure boot people
have been struggling.

Peter Z. suggested we should taint the kernel on raw I/O access, and I
tend to concur.

So what I would like to suggest is that we create a new kernel helper
function which can return an error in secure boot mode and otherwise
taints the kernel with a raw I/O taint.

What do people think?

	-hpa