conf: add support for Hyper-V PV IPIs

Support Hyper-V PV IPI enlightenment in domain config. QEMU support will
be implemented in the next patch, adding interim VIR_DOMAIN_HYPERV_IPI
cases to src/qemu/* for now.

Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>

docs/formatdomain.html.in

@@ -2007,6 +2007,7 @@
     <frequencies state='on'/>
     <reenlightenment state='on'/>
     <tlbflush state='on'/>
+    <ipi state='on'/>
   </hyperv>
   <kvm>
     <hidden state='on'/>
@@ -2147,6 +2148,12 @@
           <td>on, off</td>
           <td><span class="since">4.7.0 (QEMU 3.0)</span></td>
         </tr>
+        <tr>
+          <td>ipi</td>
+          <td>Enable PV IPI support</td>
+          <td>on, off</td>
+          <td><span class="since">4.10.0 (QEMU 3.1)</span></td>
+        </tr>
       </table>
       </dd>
       <dt><code>pvspinlock</code></dt>

docs/schemas/domaincommon.rng

@@ -5779,6 +5779,11 @@
             <ref name="featurestate"/>
           </element>
         </optional>
+        <optional>
+          <element name="ipi">
+            <ref name="featurestate"/>
+          </element>
+        </optional>
       </interleave>
     </element>
   </define>