[PATCH v3 1/4] x86/spec-ctrl: Use a taint for CET without MSR_SPEC_CTRL

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Reword the comment for 'S' to include an incompatbile set of features on the
same core.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>

v3:
 * New
---
 xen/arch/x86/spec_ctrl.c | 3 +++
 xen/common/kernel.c      | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/spec_ctrl.c b/xen/arch/x86/spec_ctrl.c
index cd5ea6aa52d9..05b86edf73d3 100644
--- a/xen/arch/x86/spec_ctrl.c
+++ b/xen/arch/x86/spec_ctrl.c
@@ -1132,7 +1132,10 @@ void __init init_speculation_mitigations(void)
     if ( read_cr4() & X86_CR4_CET )
     {
         if ( !has_spec_ctrl )
+        {
             printk(XENLOG_WARNING "?!? CET active, but no MSR_SPEC_CTRL?\n");
+            add_taint(TAINT_CPU_OUT_OF_SPEC);
+        }
         else if ( opt_ibrs == -1 )
             opt_ibrs = ibrs = true;
 
diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index fd975ae21ebc..719b08d6c76a 100644
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -373,7 +373,7 @@ unsigned int tainted;
  *  'H' - HVM forced emulation prefix is permitted.
  *  'I' - Platform is insecure (usually due to an errata on the platform).
  *  'M' - Machine had a machine check experience.
- *  'S' - Out of spec CPU (One core has a feature incompatible with others).
+ *  'S' - Out of spec CPU (Incompatible features on one or more cores).
  *
  *      The string is overwritten by the next call to print_taint().
  */
-- 
2.30.2