diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index 9e30d97743..bd892198c0 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -859,17 +859,23 @@ static void __update_vcpu_system_time(struct vcpu *v, int force)
         v->arch.pv_vcpu.pending_system_time = _u;
 }
 
-bool_t update_secondary_system_time(const struct vcpu *v,
+bool_t update_secondary_system_time(struct vcpu *v,
                                     struct vcpu_time_info *u)
 {
     XEN_GUEST_HANDLE(vcpu_time_info_t) user_u = v->arch.time_info_guest;
+    smap_check_policy_t saved_policy;
 
     if ( guest_handle_is_null(user_u) )
         return 1;
 
+    saved_policy = smap_policy_change(v, SMAP_CHECK_ENABLED);
+
     /* 1. Update userspace version. */
     if ( __copy_field_to_guest(user_u, u, version) == sizeof(u->version) )
+    {
+        smap_policy_change(v, saved_policy);
         return 0;
+    }
     wmb();
     /* 2. Update all other userspace fields. */
     __copy_to_guest(user_u, u, 1);
@@ -878,6 +884,8 @@ bool_t update_secondary_system_time(const struct vcpu *v,
     u->version = version_update_end(u->version);
     __copy_field_to_guest(user_u, u, version);
 
+    smap_policy_change(v, saved_policy);
+
     return 1;
 }
 
diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h
index 112d0b1637..83329ed3bc 100644
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -468,7 +468,7 @@ smap_check_policy_t smap_policy_change(struct vcpu *v,
 #define hvm_svm         hvm_vcpu.u.svm
 
 bool_t update_runstate_area(struct vcpu *);
-bool_t update_secondary_system_time(const struct vcpu *,
+bool_t update_secondary_system_time(struct vcpu *,
                                     struct vcpu_time_info *);
 
 void vcpu_show_execution_state(struct vcpu *);