qemu: format intel-iommu on the command line

<devices>
  <iommu model='intel'/>
</devices>

results in:

-device intel-iommu

https://bugzilla.redhat.com/show_bug.cgi?id=1235580

src/qemu/qemu_command.c

@@ -6163,6 +6163,38 @@ qemuBuildBootCommandLine(virCommandPtr cmd,
 }
 
 
+static int
+qemuBuildIOMMUCommandLine(virCommandPtr cmd,
+                          const virDomainDef *def,
+                          virQEMUCapsPtr qemuCaps)
+{
+    if (!def->iommu)
+        return 0;
+
+    switch (def->iommu->model) {
+    case VIR_DOMAIN_IOMMU_MODEL_INTEL:
+        if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_INTEL_IOMMU)) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                           _("IOMMU device: '%s' is not supported with "
+                             "this QEMU binary"),
+                           virDomainIOMMUModelTypeToString(def->iommu->model));
+            return -1;
+        }
+        if (!qemuDomainMachineIsQ35(def)) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                           _("IOMMU device: '%s' is only supported with "
+                             "Q35 machines"),
+                           virDomainIOMMUModelTypeToString(def->iommu->model));
+            return -1;
+        }
+        virCommandAddArgList(cmd, "-device", "intel-iommu", NULL);
+    case VIR_DOMAIN_IOMMU_MODEL_LAST:
+        break;
+    }
+    return 0;
+}
+
+
 static int
 qemuBuildGlobalControllerCommandLine(virCommandPtr cmd,
                                      const virDomainDef *def,
@@ -9236,6 +9268,9 @@ qemuBuildCommandLine(virQEMUDriverPtr driver,
     if (qemuBuildBootCommandLine(cmd, def, qemuCaps) < 0)
         goto error;
 
+    if (qemuBuildIOMMUCommandLine(cmd, def, qemuCaps) < 0)
+        goto error;
+
     if (qemuBuildGlobalControllerCommandLine(cmd, def, qemuCaps) < 0)
         goto error;
 

tests/qemuxml2argvdata/qemuxml2argv-intel-iommu.args

@@ -0,0 +1,22 @@
+LC_ALL=C \
+PATH=/bin \
+HOME=/home/test \
+USER=test \
+LOGNAME=test \
+QEMU_AUDIO_DRV=none \
+/usr/bin/qemu \
+-name QEMUGuest1 \
+-S \
+-M q35 \
+-m 214 \
+-smp 1,sockets=1,cores=1,threads=1 \
+-uuid c7a5fdbd-edaf-9455-926a-d65c16db1809 \
+-nographic \
+-nodefaults \
+-monitor unix:/tmp/lib/domain--1-QEMUGuest1/monitor.sock,server,nowait \
+-no-acpi \
+-boot c \
+-device intel-iommu \
+-device i82801b11-bridge,id=pci.1,bus=pcie.0,addr=0x1e \
+-device pci-bridge,chassis_nr=2,id=pci.2,bus=pci.1,addr=0x0 \
+-device virtio-balloon-pci,id=balloon0,bus=pci.2,addr=0x1

tests/qemuxml2argvtest.c

@@ -2027,6 +2027,8 @@ mymain(void)
                               QEMU_CAPS_NODEFCONFIG, QEMU_CAPS_USB_HUB);
 
     DO_TEST("acpi-table", NONE);
+    DO_TEST("intel-iommu", QEMU_CAPS_DEVICE_PCI_BRIDGE,
+            QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE, QEMU_CAPS_DEVICE_INTEL_IOMMU);
 
     qemuTestDriverFree(&driver);