With all the pieces now in place, turn CET-IBT on when available.
MSR_S_CET, like SMEP/SMAP, controls Ring1 meaning that ENDBR_EN can't be
enabled for Xen independently of PV32 kernels. As we already disable PV32 for
CET-SS, extend this to all CET, adjusting the documentation/comments as
appropriate.
Introduce a cet=no-ibt command line option to allow the admin to disable IBT
even when everything else is configured correctly.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Andrew Cooper
cdbe2b0a1a