diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
index 097796df72..717f2621e2 100644
--- a/docs/formatdomain.rst
+++ b/docs/formatdomain.rst
@@ -1820,7 +1820,7 @@ Hypervisors may allow certain CPU / machine features to be toggled on/off.
      <apic/>
      <hap/>
      <privnet/>
-     <hyperv>
+     <hyperv mode='custom'>
        <relaxed state='on'/>
        <vapic state='on'/>
        <spinlocks state='on' retries='4096'/>
@@ -1922,6 +1922,14 @@ are:
    evmcs           Enable Enlightened VMCS                                                on, off                                      :since:`4.10.0 (QEMU 3.1)`
    =============== ====================================================================== ============================================ =======================================================
 
+   :since:`Since 8.0.0` , the hypervisor can be configured further by setting
+   the ``mode`` attribute to one of the following values:
+
+   ``custom``
+      Set exactly the specified features.
+
+   The ``mode`` attribute can be omitted and will default to ``custom``.
+
 ``pvspinlock``
    Notify the guest that the host supports paravirtual spinlocks for example by
    exposing the pvticketlocks mechanism. This feature can be explicitly disabled