diff --git a/xen/arch/x86/spec_ctrl.c b/xen/arch/x86/spec_ctrl.c
index 7ded6ecba1..1e226102d3 100644
--- a/xen/arch/x86/spec_ctrl.c
+++ b/xen/arch/x86/spec_ctrl.c
@@ -919,13 +919,14 @@ void __init init_speculation_mitigations(void)
                      boot_cpu_has(X86_FEATURE_IBRS));
 
     /*
-     * First, disable the use of retpolines if Xen is using shadow stacks, as
-     * they are incompatible.
+     * First, disable the use of retpolines if Xen is using CET.  Retpolines
+     * are a ROP gadget so incompatbile with Shadow Stacks, while IBT depends
+     * on executing indirect branches for the safety properties to apply.
      *
      * In the absence of retpolines, IBRS needs to be used for speculative
      * safety.  All CET-capable hardware has efficient IBRS.
      */
-    if ( cpu_has_xen_shstk )
+    if ( read_cr4() & X86_CR4_CET )
     {
         if ( !has_spec_ctrl )
             printk(XENLOG_WARNING "?!? CET active, but no MSR_SPEC_CTRL?\n");