conf: add <driver intremap> to <iommu>

Add a new attribute to control interrupt remapping.

https://bugzilla.redhat.com/show_bug.cgi?id=1427005

docs/formatdomain.html.in

@@ -7396,7 +7396,9 @@ qemu-kvm -net nic,model=? /dev/null
 <pre>
 ...
 &lt;devices&gt;
-  &lt;iommu model='intel'/&gt;
+  &lt;iommu model='intel'&gt;
+    &lt;driver intremap='on'/&gt;
+  &lt;/iommu&gt;
 &lt;/devices&gt;
 ...
 </pre>
@@ -7407,6 +7409,26 @@ qemu-kvm -net nic,model=? /dev/null
           Currently only the <code>intel</code> model is supported.
         </p>
       </dd>
+      <dt><code>driver</code></dt>
+      <dd>
+        <p>
+          The <code>driver</code> subelement can be used to configure
+          additional options:
+        </p>
+        <dl>
+          <dt><code>intremap</code></dt>
+          <dd>
+            <p>
+              The <code>intremap</code> attribute with possible values
+              <code>on</code> and <code>off</code> can be used to
+              turn on interrupt remapping, a part of the VT-d functionality.
+              Currently this requires split I/O APIC
+              (<code>&lt;ioapic driver='qemu'/&gt;</code>).
+              <span class="since">Since 3.4.0</span> (QEMU/KVM only)
+            </p>
+          </dd>
+        </dl>
+      </dd>
     </dl>
 
     <h3><a name="seclabel">Security label</a></h3>

docs/schemas/domaincommon.rng

@@ -3947,6 +3947,15 @@
       <attribute name="model">
         <value>intel</value>
       </attribute>
+      <optional>
+        <element name="driver">
+          <optional>
+            <attribute name="intremap">
+              <ref name="virOnOff"/>
+            </attribute>
+          </optional>
+        </element>
+      </optional>
     </element>
   </define>
 

src/conf/domain_conf.c

@@ -14141,12 +14141,16 @@ virDomainMemoryDefParseXML(xmlNodePtr memdevNode,
 
 
 static virDomainIOMMUDefPtr
-virDomainIOMMUDefParseXML(xmlNodePtr node)
+virDomainIOMMUDefParseXML(xmlNodePtr node,
+                          xmlXPathContextPtr ctxt)
 {
     virDomainIOMMUDefPtr iommu = NULL, ret = NULL;
+    xmlNodePtr save = ctxt->node;
     char *tmp = NULL;
     int val;
 
+    ctxt->node = node;
+
     if (VIR_ALLOC(iommu) < 0)
         goto cleanup;
 
@@ -14163,10 +14167,20 @@ virDomainIOMMUDefParseXML(xmlNodePtr node)
 
     iommu->model = val;
 
+    VIR_FREE(tmp);
+    if ((tmp = virXPathString("string(./driver/@intremap)", ctxt))) {
+        if ((val = virTristateSwitchTypeFromString(tmp)) < 0) {
+            virReportError(VIR_ERR_XML_ERROR, _("unknown intremap value: %s"), tmp);
+            goto cleanup;
+        }
+        iommu->intremap = val;
+    }
+
     ret = iommu;
     iommu = NULL;
 
  cleanup:
+    ctxt->node = save;
     VIR_FREE(iommu);
     VIR_FREE(tmp);
     return ret;
@@ -14319,7 +14333,7 @@ virDomainDeviceDefParse(const char *xmlStr,
             goto error;
         break;
     case VIR_DOMAIN_DEVICE_IOMMU:
-        if (!(dev->data.iommu = virDomainIOMMUDefParseXML(node)))
+        if (!(dev->data.iommu = virDomainIOMMUDefParseXML(node, ctxt)))
             goto error;
         break;
     case VIR_DOMAIN_DEVICE_NONE:
@@ -18449,7 +18463,7 @@ virDomainDefParseXML(xmlDocPtr xml,
     }
 
     if (n > 0) {
-        if (!(def->iommu = virDomainIOMMUDefParseXML(nodes[0])))
+        if (!(def->iommu = virDomainIOMMUDefParseXML(nodes[0], ctxt)))
             goto error;
     }
     VIR_FREE(nodes);
@@ -24125,8 +24139,24 @@ static void
 virDomainIOMMUDefFormat(virBufferPtr buf,
                         const virDomainIOMMUDef *iommu)
 {
-    virBufferAsprintf(buf, "<iommu model='%s'/>\n",
+    virBuffer childBuf = VIR_BUFFER_INITIALIZER;
+
+    virBufferAdjustIndent(&childBuf, virBufferGetIndent(buf, false) + 2);
+
+    if (iommu->intremap != VIR_TRISTATE_SWITCH_ABSENT) {
+        virBufferAsprintf(&childBuf, "<driver intremap='%s'/>\n",
+                          virTristateSwitchTypeToString(iommu->intremap));
+    }
+
+    virBufferAsprintf(buf, "<iommu model='%s'",
                       virDomainIOMMUModelTypeToString(iommu->model));
+    if (virBufferUse(&childBuf)) {
+        virBufferAddLit(buf, ">\n");
+        virBufferAddBuffer(buf, &childBuf);
+        virBufferAddLit(buf, "</iommu>\n");
+    } else {
+        virBufferAddLit(buf, "/>\n");
+    }
 }
 
 

src/conf/domain_conf.h

@@ -2209,6 +2209,7 @@ typedef enum {
 
 struct _virDomainIOMMUDef {
     virDomainIOMMUModel model;
+    virTristateSwitch intremap;
 };
 /*
  * Guest VM main configuration

tests/qemuxml2argvdata/qemuxml2argv-intel-iommu-ioapic.xml

@@ -24,6 +24,8 @@
     <input type='mouse' bus='ps2'/>
     <input type='keyboard' bus='ps2'/>
     <memballoon model='none'/>
-    <iommu model='intel'/>
+    <iommu model='intel'>
+      <driver intremap='on'/>
+    </iommu>
   </devices>
 </domain>