Always add 'console' matching the 'serial' device

We have been formatting the first serial device also
as a console device, but only if there were no other consoles.

If there is a <serial> device present in the XML, but no serial
<console>, or if there isn't any <console> at all but the domain
definition hasn't gone through a parse->format->parse round-trip,
the <console> device would not be formatted.

Change the code to always add the stub device for the first
serial device.

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1089914

src/conf/domain_conf.c

@@ -3588,6 +3588,27 @@ virDomainDefPostParseInternal(virDomainDefPtr def,
             def->consoles[0]->deviceType = VIR_DOMAIN_CHR_DEVICE_TYPE_CONSOLE;
             def->consoles[0]->targetType = VIR_DOMAIN_CHR_CONSOLE_TARGET_TYPE_SERIAL;
         }
+    } else if (def->os.type == VIR_DOMAIN_OSTYPE_HVM && def->nserials > 0 &&
+               def->serials[0]->deviceType == VIR_DOMAIN_CHR_DEVICE_TYPE_SERIAL &&
+               def->serials[0]->targetType == VIR_DOMAIN_CHR_SERIAL_TARGET_TYPE_ISA) {
+        /* Create a stub console to match the serial port.
+         * console[0] either does not exist
+         *                or has a different type than SERIAL or NONE.
+         */
+        virDomainChrDefPtr chr;
+        if (VIR_ALLOC(chr) < 0)
+            return -1;
+
+        if (VIR_INSERT_ELEMENT(def->consoles,
+                               0,
+                               def->nconsoles,
+                               chr) < 0) {
+            VIR_FREE(chr);
+            return -1;
+        }
+
+        def->consoles[0]->deviceType = VIR_DOMAIN_CHR_DEVICE_TYPE_CONSOLE;
+        def->consoles[0]->targetType = VIR_DOMAIN_CHR_CONSOLE_TARGET_TYPE_SERIAL;
     }
 
     if (virDomainDefRejectDuplicateControllers(def) < 0)
@@ -21540,6 +21561,10 @@ virDomainDefFormatInternal(virDomainDefPtr def,
         if (virDomainChrDefFormat(buf, &console, flags) < 0)
             goto error;
     }
+    /* The back-compat console device stub is added when parsing the domain XML
+     * and handled above, this is for formatting definitions created via other
+     * means.
+     */
     if (def->os.type == VIR_DOMAIN_OSTYPE_HVM &&
         def->nconsoles == 0 &&
         def->nserials > 0) {

tests/qemuxml2argvdata/qemuxml2argv-console-compat2.xml

@@ -0,0 +1,35 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219100</memory>
+  <currentMemory unit='KiB'>219100</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu</emulator>
+    <disk type='block' device='disk'>
+      <driver name='qemu' type='raw'/>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='hda' bus='ide'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
+    <controller type='usb' index='0'/>
+    <controller type='ide' index='0'/>
+    <controller type='pci' index='0' model='pci-root'/>
+    <controller type='virtio-serial' index='0'/>
+    <serial type='pty'>
+      <target port='0'/>
+    </serial>
+    <console type='pty'>
+      <target type='virtio' port='0'/>
+    </console>
+    <memballoon model='none'/>
+  </devices>
+</domain>

tests/qemuxml2xmloutdata/qemuxml2xmlout-console-compat2.xml

@@ -0,0 +1,38 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219100</memory>
+  <currentMemory unit='KiB'>219100</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu</emulator>
+    <disk type='block' device='disk'>
+      <driver name='qemu' type='raw'/>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='hda' bus='ide'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
+    <controller type='usb' index='0'/>
+    <controller type='ide' index='0'/>
+    <controller type='pci' index='0' model='pci-root'/>
+    <controller type='virtio-serial' index='0'/>
+    <serial type='pty'>
+      <target port='0'/>
+    </serial>
+    <console type='pty'>
+      <target type='serial' port='0'/>
+    </console>
+    <console type='pty'>
+      <target type='virtio' port='0'/>
+    </console>
+    <memballoon model='none'/>
+  </devices>
+</domain>

tests/qemuxml2xmltest.c

@@ -472,6 +472,7 @@ mymain(void)
     DO_TEST("serial-spiceport-nospice");
     DO_TEST("parallel-tcp");
     DO_TEST("console-compat");
+    DO_TEST_DIFFERENT("console-compat2");
     DO_TEST("console-virtio-many");
     DO_TEST("channel-guestfwd");
     DO_TEST("channel-virtio");