qemu: Fix updating device with boot order

Commit v3.7.0-14-gc57f3fd2 prevented adding a <boot order='x'/>
element to an inactive domain with global <boot dev='...'/> element.
However, as a result of that change updating any device with boot order
would fail with 'boot order X is already used by another device', where
"another device" is in fact the device which is being updated.

To fix this we have to ignore the device which we're about to update
when checking for boot order conflicts.

https://bugzilla.redhat.com/show_bug.cgi?id=1546971Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

src/conf/domain_conf.c

@@ -27381,18 +27381,30 @@ virDomainDeviceIsUSB(virDomainDeviceDefPtr dev)
     return false;
 }
 
+
+typedef struct _virDomainCompatibleDeviceData virDomainCompatibleDeviceData;
+typedef virDomainCompatibleDeviceData *virDomainCompatibleDeviceDataPtr;
+struct _virDomainCompatibleDeviceData {
+    virDomainDeviceInfoPtr newInfo;
+    virDomainDeviceInfoPtr oldInfo;
+};
+
 static int
 virDomainDeviceInfoCheckBootIndex(virDomainDefPtr def ATTRIBUTE_UNUSED,
                                   virDomainDeviceDefPtr device ATTRIBUTE_UNUSED,
                                   virDomainDeviceInfoPtr info,
                                   void *opaque)
 {
-    virDomainDeviceInfoPtr newinfo = opaque;
+    virDomainCompatibleDeviceDataPtr data = opaque;
+
+    /* Ignore the device we're about to update */
+    if (data->oldInfo == info)
+        return 0;
 
-    if (info->bootIndex == newinfo->bootIndex) {
+    if (info->bootIndex == data->newInfo->bootIndex) {
         virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                        _("boot order %u is already used by another device"),
-                       newinfo->bootIndex);
+                       data->newInfo->bootIndex);
         return -1;
     }
     return 0;
@@ -27401,9 +27413,12 @@ virDomainDeviceInfoCheckBootIndex(virDomainDefPtr def ATTRIBUTE_UNUSED,
 int
 virDomainDefCompatibleDevice(virDomainDefPtr def,
                              virDomainDeviceDefPtr dev,
-                             virDomainDeviceDefPtr oldDev ATTRIBUTE_UNUSED)
+                             virDomainDeviceDefPtr oldDev)
 {
-    virDomainDeviceInfoPtr info = virDomainDeviceGetInfo(dev);
+    virDomainCompatibleDeviceData data = {
+        .newInfo = virDomainDeviceGetInfo(dev),
+        .oldInfo = virDomainDeviceGetInfo(oldDev),
+    };
 
     if (!virDomainDefHasUSB(def) &&
         def->os.type != VIR_DOMAIN_OSTYPE_EXE &&
@@ -27414,7 +27429,7 @@ virDomainDefCompatibleDevice(virDomainDefPtr def,
         return -1;
     }
 
-    if (info && info->bootIndex > 0) {
+    if (data.newInfo && data.newInfo->bootIndex > 0) {
         if (def->os.nBootDevs > 0) {
             virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
                            _("per-device boot elements cannot be used"
@@ -27423,7 +27438,7 @@ virDomainDefCompatibleDevice(virDomainDefPtr def,
         }
         if (virDomainDeviceInfoIterate(def,
                                        virDomainDeviceInfoCheckBootIndex,
-                                       info) < 0)
+                                       &data) < 0)
             return -1;
     }