This only checks that it was available from the CPU.
To be complete an additional check should be made to show that it
was actually enabled from the firmware.
This will require a kernel modification though because MSR access
will be forbidden from userland while in kernel lockdown.
New enough hardware to have this feature isn't going to be in the marketplace
for a while. To use that newer hardware requires a very recent kernel (5.6 at
least, although it will probably be at least 5.9 by the time the hardware is
released).
The CET status will be used in future functionality.
