conf: Introduce optional startupPolicy attribute for cdrom and floppy

This attribute says what to do with cdrom (or floppy) if
the source is missing. It accepts:
- mandatory - fail if missing for any reason (the default)
- requisite - fail if missing on boot up, drop if missing on
              migrate/restore/revert
- optional  - drop if missing at any start attempt.

However, this patch introduces only XML part of this new
functionality.

docs/formatdomain.html.in

@@ -891,7 +891,7 @@
   <devices>
     <disk type='file' snapshot='external'>
       <driver name="tap" type="aio" cache="default"/>
-      <source file='/var/lib/xen/images/fv0'/>
+      <source file='/var/lib/xen/images/fv0'/ startupPolicy='optional'>
       <target dev='hda' bus='ide'/>
       <boot order='2'/>
       <encryption type='...'>
@@ -962,7 +962,29 @@
         "network", the <code>source</code> may have zero or
         more <code>host</code> sub-elements used to specify the hosts
         to connect.
-        <span class="since">Since 0.0.3</span></dd>
+        <span class="since">Since 0.0.3</span>
+        For "file" disk type which represents cdrom or floppy
+        (the <code>device</code> attribute) it is possible to define
+        policy what to do with disk if source is not accessible.
+        This is done by <code>startupPolicy</code> attribute accepting
+        these values:
+        <table class="top_table">
+          <tr>
+            <td> mandatory </td>
+            <td> fail if missing for any reason (the default) </td>
+          </tr>
+          <tr>
+            <td> requisite </td>
+            <td> fail if missing on boot up,
+                 drop if missing on migrate/restore/revert </td>
+          </tr>
+          <tr>
+            <td> optional </td>
+            <td> drop if missing at any start attempt </td>
+          </tr>
+        </table>
+        <span class="since">Since 0.9.7</span>
+        </dd>
       <dt><code>target</code></dt>
       <dd>The <code>target</code> element controls the bus / device
         under which the disk is exposed to the guest

docs/schemas/domaincommon.rng

@@ -665,6 +665,17 @@
       </interleave>
     </element>
   </define>
+
+  <define name="startupPolicy">
+    <attribute name="startupPolicy">
+      <choice>
+        <value>mandatory</value>
+        <value>requisite</value>
+        <value>optional</value>
+      </choice>
+    </attribute>
+  </define>
+
   <!--
       A disk description can be either of type file or block
       The name of the attribute on the source element depends on the type
@@ -692,9 +703,14 @@
           <interleave>
             <optional>
               <element name="source">
-                <attribute name="file">
-                  <ref name="absFilePath"/>
-                </attribute>
+                <optional>
+                  <attribute name="file">
+                    <ref name="absFilePath"/>
+                  </attribute>
+                </optional>
+                <optional>
+                  <ref name="startupPolicy"/>
+                </optional>
                 <empty/>
               </element>
             </optional>

src/conf/domain_conf.c

@@ -578,6 +578,12 @@ VIR_ENUM_IMPL(virDomainNumatuneMemMode, VIR_DOMAIN_NUMATUNE_MEM_LAST,
               "preferred",
               "interleave");
 
+VIR_ENUM_IMPL(virDomainStartupPolicy, VIR_DOMAIN_STARTUP_POLICY_LAST,
+              "default",
+              "mandatory",
+              "requisite",
+              "optional");
+
 #define virDomainReportError(code, ...)                              \
     virReportErrorHelper(VIR_FROM_DOMAIN, code, __FILE__,            \
                          __FUNCTION__, __LINE__, __VA_ARGS__)
@@ -2319,6 +2325,7 @@ virDomainDiskDefParseXML(virCapsPtr caps,
     char *devaddr = NULL;
     virStorageEncryptionPtr encryption = NULL;
     char *serial = NULL;
+    char *startupPolicy = NULL;
 
     if (VIR_ALLOC(def) < 0) {
         virReportOOMError();
@@ -2347,6 +2354,7 @@ virDomainDiskDefParseXML(virCapsPtr caps,
                 switch (def->type) {
                 case VIR_DOMAIN_DISK_TYPE_FILE:
                     source = virXMLPropString(cur, "file");
+                    startupPolicy = virXMLPropString(cur, "startupPolicy");
                     break;
                 case VIR_DOMAIN_DISK_TYPE_BLOCK:
                     source = virXMLPropString(cur, "dev");
@@ -2646,6 +2654,27 @@ virDomainDiskDefParseXML(virCapsPtr caps,
             goto error;
     }
 
+    if (startupPolicy) {
+        int i;
+
+        if ((i = virDomainStartupPolicyTypeFromString(startupPolicy)) < 0) {
+            virDomainReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                                 _("unknown startupPolicy value '%s'"),
+                                 startupPolicy);
+            goto error;
+        }
+
+        if (def->device != VIR_DOMAIN_DISK_DEVICE_CDROM &&
+            def->device != VIR_DOMAIN_DISK_DEVICE_FLOPPY) {
+            virDomainReportError(VIR_ERR_INVALID_ARG,
+                                 _("Setting disk %s is allowed only for "
+                                   "cdrom or floppy"),
+                                 startupPolicy);
+            goto error;
+        }
+        def->startupPolicy = i;
+    }
+
     def->src = source;
     source = NULL;
     def->dst = target;
@@ -2701,6 +2730,7 @@ cleanup:
     VIR_FREE(devaddr);
     VIR_FREE(serial);
     virStorageEncryptionFree(encryption);
+    VIR_FREE(startupPolicy);
 
     return def;
 
@@ -9176,6 +9206,7 @@ virDomainDiskDefFormat(virBufferPtr buf,
     const char *iomode = virDomainDiskIoTypeToString(def->iomode);
     const char *ioeventfd = virDomainIoEventFdTypeToString(def->ioeventfd);
     const char *event_idx = virDomainVirtioEventIdxTypeToString(def->event_idx);
+    const char *startupPolicy = virDomainStartupPolicyTypeToString(def->startupPolicy);
 
     if (!type) {
         virDomainReportError(VIR_ERR_INTERNAL_ERROR,
@@ -9234,11 +9265,17 @@ virDomainDiskDefFormat(virBufferPtr buf,
         virBufferAsprintf(buf, "/>\n");
     }
 
-    if (def->src || def->nhosts > 0) {
+    if (def->src || def->nhosts > 0 ||
+        def->startupPolicy) {
         switch (def->type) {
         case VIR_DOMAIN_DISK_TYPE_FILE:
-            virBufferEscapeString(buf, "      <source file='%s'/>\n",
-                                  def->src);
+            virBufferAsprintf(buf,"      <source");
+            if (def->src)
+                virBufferEscapeString(buf, " file='%s'", def->src);
+            if (def->startupPolicy)
+                virBufferEscapeString(buf, " startupPolicy='%s'",
+                                      startupPolicy);
+            virBufferAsprintf(buf, "/>\n");
             break;
         case VIR_DOMAIN_DISK_TYPE_BLOCK:
             virBufferEscapeString(buf, "      <source dev='%s'/>\n",

src/conf/domain_conf.h

@@ -269,6 +269,15 @@ enum virDomainSnapshotState {
     VIR_DOMAIN_DISK_SNAPSHOT = VIR_DOMAIN_LAST,
 };
 
+enum virDomainStartupPolicy {
+    VIR_DOMAIN_STARTUP_POLICY_DEFAULT = 0,
+    VIR_DOMAIN_STARTUP_POLICY_MANDATORY,
+    VIR_DOMAIN_STARTUP_POLICY_REQUISITE,
+    VIR_DOMAIN_STARTUP_POLICY_OPTIONAL,
+
+    VIR_DOMAIN_STARTUP_POLICY_LAST
+};
+
 /* Stores the virtual disk configuration */
 typedef struct _virDomainDiskDef virDomainDiskDef;
 typedef virDomainDiskDef *virDomainDiskDefPtr;
@@ -292,6 +301,7 @@ struct _virDomainDiskDef {
     int ioeventfd;
     int event_idx;
     int snapshot; /* enum virDomainDiskSnapshot */
+    int startupPolicy; /* enum virDomainStartupPolicy */
     unsigned int readonly : 1;
     unsigned int shared : 1;
     unsigned int transient : 1;
@@ -1938,4 +1948,5 @@ VIR_ENUM_DECL(virDomainTimerTrack)
 VIR_ENUM_DECL(virDomainTimerTickpolicy)
 VIR_ENUM_DECL(virDomainTimerMode)
 
+VIR_ENUM_DECL(virDomainStartupPolicy)
 #endif /* __DOMAIN_CONF_H */

src/libvirt_private.syms

@@ -430,6 +430,8 @@ virDomainSnapshotUpdateRelations;
 virDomainSoundDefFree;
 virDomainSoundModelTypeFromString;
 virDomainSoundModelTypeToString;
+virDomainStartupPolicyTypeFromString;
+virDomainStartupPolicyTypeToString;
 virDomainStateReasonFromString;
 virDomainStateReasonToString;
 virDomainStateTypeFromString;

tests/qemuxml2xmloutdata/qemuxml2xmlout-disk-cdrom-empty.xml

+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory>219100</memory>
+  <currentMemory>219100</currentMemory>
+  <vcpu>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'>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='hda' bus='ide'/>
+      <address type='drive' controller='0' bus='0' unit='0'/>
+    </disk>
+    <disk type='file' device='cdrom'>
+      <target dev='hdc' bus='ide'/>
+      <source startupPolicy='optional'/>
+      <readonly/>
+      <address type='drive' controller='0' bus='1' unit='0'/>
+    </disk>
+    <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
+  </devices>
+</domain>