... disabled by default. There is a lot of work before FRED can be enabled by
default.
One part of FRED, the LKGS (Load Kernel GS) instruction, is enumerated
separately but expected to be mandatory as FRED disallows the SWAPGS
instruction. Normally, we'd have to check both CPUID bits, but Xen does not
use GS like most other software, and can manage without LKGS.
FRED formally removes the use of Ring1 and Ring2, meaning we cannot run 32bit
PV guests. As already done with CET, disable PV32 if using FRED, except in
shim mode where FRED is disabled by default.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Andrew Cooper
743fd27306