qemu: Prevent two threshold events when it was registered with index

Remember whether the user passed an explicit index when registering the
event so that we can avoid the top level event when it isn't needed.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

src/qemu/qemu_driver.c

@@ -19623,6 +19623,10 @@ qemuDomainSetBlockThreshold(virDomainPtr dom,
     if (qemuDomainObjExitMonitor(driver, vm) < 0 || rc < 0)
         goto endjob;
 
+    /* we need to remember whether the threshold was registered with an explicit
+     * index to fire the correct event */
+    src->thresholdEventWithIndex = !!strchr(dev, '[');
+
     ret = 0;
 
  endjob:

src/qemu/qemu_process.c

@@ -1487,7 +1487,8 @@ qemuProcessHandleBlockThreshold(qemuMonitor *mon G_GNUC_UNUSED,
         if (virStorageSourceIsLocalStorage(src))
             path = src->path;
 
-        if (src == disk->src) {
+        if (src == disk->src &&
+            !src->thresholdEventWithIndex) {
             g_autofree char *dev = qemuDomainDiskBackingStoreGetName(disk, 0);
 
             eventDevice = virDomainEventBlockThresholdNewFromObj(vm, dev, path,