diff --git a/xen/include/public/arch-x86/xen.h b/xen/include/public/arch-x86/xen.h
index 3f68a43c30..ff918310f6 100644
--- a/xen/include/public/arch-x86/xen.h
+++ b/xen/include/public/arch-x86/xen.h
@@ -162,10 +162,12 @@ typedef uint64_t tsc_timestamp_t; /* RDTSC timestamp */
  * The following is all CPU context. Note that the fpu_ctxt block is filled
  * in by FXSAVE if the CPU has feature FXSR; otherwise FSAVE is used.
  *
- * Also note that when calling DOMCTL_setvcpucontext and VCPUOP_initialise for
- * HVM guests, not all information in this structure is updated, the fields
- * read include: fpu_ctxt (if VGCT_I387_VALID is set), flags, user_regs and
- * debugreg[*].
+ * Also note that when calling DOMCTL_setvcpucontext for HVM guests, not all
+ * information in this structure is updated, the fields read include: fpu_ctxt
+ * (if VGCT_I387_VALID is set), flags, user_regs and debugreg[*].
+ *
+ * Note: VCPUOP_initialise for HVM guests is non-symetric with
+ * DOMCTL_setvcpucontext, and uses struct vcpu_hvm_context from hvm/hvm_vcpu.h
  */
 struct vcpu_guest_context {
     /* FPU registers come first so they can be aligned for FXSAVE/FXRSTOR. */