qemu: setup infrastructure to handle NIC_RX_FILTER_CHANGED event

NIC_RX_FILTER_CHANGED is sent by qemu any time a NIC driver in the
guest modified the NIC's RX Filter (for example, if the MAC address of
the NIC is changed by the guest).

This patch doesn't do anything useful with that event; it just sets up
all the plumbing to get news of the event into a worker thread with
all proper locking/reference counting, and provide an easy place to
add in desired functionality.

See src/qemu/EVENTHANDLERS.txt for information/instructions on adding
a libvirt-internal handler for a qemu event (using
NIC_RX_FILTER_CHANGED as an example).

src/qemu/qemu_domain.h

@@ -195,6 +195,7 @@ typedef enum {
     QEMU_PROCESS_EVENT_WATCHDOG = 0,
     QEMU_PROCESS_EVENT_GUESTPANIC,
     QEMU_PROCESS_EVENT_DEVICE_DELETED,
+    QEMU_PROCESS_EVENT_NIC_RX_FILTER_CHANGED,
 
     QEMU_PROCESS_EVENT_LAST
 } qemuProcessEventType;

src/qemu/qemu_driver.c

@@ -4146,6 +4146,58 @@ processDeviceDeletedEvent(virQEMUDriverPtr driver,
 }
 
 
+static void
+processNicRxFilterChangedEvent(virQEMUDriverPtr driver,
+                               virDomainObjPtr vm,
+                               char *devAlias)
+{
+    virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virDomainDeviceDef dev;
+    virDomainNetDefPtr def;
+
+    VIR_DEBUG("Received NIC_RX_FILTER_CHANGED event for device %s "
+              "from domain %p %s",
+              devAlias, vm, vm->def->name);
+
+    if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0)
+        goto cleanup;
+
+    if (!virDomainObjIsActive(vm)) {
+        VIR_DEBUG("Domain is not running");
+        goto endjob;
+    }
+
+    if (virDomainDefFindDevice(vm->def, devAlias, &dev, true) < 0) {
+        VIR_WARN("NIC_RX_FILTER_CHANGED event received for "
+                 "non-existent device %s in domain %s",
+                 devAlias, vm->def->name);
+        goto endjob;
+    }
+    if (dev.type != VIR_DOMAIN_DEVICE_NET) {
+        VIR_WARN("NIC_RX_FILTER_CHANGED event received for "
+                 "non-network device %s in domain %s",
+                 devAlias, vm->def->name);
+        goto endjob;
+    }
+    def = dev.data.net;
+
+    /* handle the event - send query-rx-filter and respond to it. */
+
+    VIR_DEBUG("process NIC_RX_FILTER_CHANGED event for network "
+              "device %s in domain %s", def->info.alias, vm->def->name);
+
+ endjob:
+    /* We had an extra reference to vm before starting a new job so ending the
+     * job is guaranteed not to remove the last reference.
+     */
+    ignore_value(qemuDomainObjEndJob(driver, vm));
+
+ cleanup:
+    VIR_FREE(devAlias);
+    virObjectUnref(cfg);
+}
+
+
 static void qemuProcessEventHandler(void *data, void *opaque)
 {
     struct qemuProcessEvent *processEvent = data;
@@ -4166,6 +4218,9 @@ static void qemuProcessEventHandler(void *data, void *opaque)
     case QEMU_PROCESS_EVENT_DEVICE_DELETED:
         processDeviceDeletedEvent(driver, vm, processEvent->data);
         break;
+    case QEMU_PROCESS_EVENT_NIC_RX_FILTER_CHANGED:
+        processNicRxFilterChangedEvent(driver, vm, processEvent->data);
+        break;
     case QEMU_PROCESS_EVENT_LAST:
         break;
     }

src/qemu/qemu_monitor.c

@@ -1387,6 +1387,19 @@ qemuMonitorEmitDeviceDeleted(qemuMonitorPtr mon,
 }
 
 
+int
+qemuMonitorEmitNicRxFilterChanged(qemuMonitorPtr mon,
+                                  const char *devAlias)
+{
+    int ret = -1;
+    VIR_DEBUG("mon=%p", mon);
+
+    QEMU_MONITOR_CALLBACK(mon, ret, domainNicRxFilterChanged, mon->vm, devAlias);
+
+    return ret;
+}
+
+
 int qemuMonitorSetCapabilities(qemuMonitorPtr mon)
 {
     int ret;

src/qemu/qemu_monitor.h

@@ -171,6 +171,10 @@ typedef int (*qemuMonitorDomainDeviceDeletedCallback)(qemuMonitorPtr mon,
                                                       virDomainObjPtr vm,
                                                       const char *devAlias,
                                                       void *opaque);
+typedef int (*qemuMonitorDomainNicRxFilterChangedCallback)(qemuMonitorPtr mon,
+                                                           virDomainObjPtr vm,
+                                                           const char *devAlias,
+                                                           void *opaque);
 
 typedef struct _qemuMonitorCallbacks qemuMonitorCallbacks;
 typedef qemuMonitorCallbacks *qemuMonitorCallbacksPtr;
@@ -197,6 +201,7 @@ struct _qemuMonitorCallbacks {
     qemuMonitorDomainPMSuspendDiskCallback domainPMSuspendDisk;
     qemuMonitorDomainGuestPanicCallback domainGuestPanic;
     qemuMonitorDomainDeviceDeletedCallback domainDeviceDeleted;
+    qemuMonitorDomainNicRxFilterChangedCallback domainNicRxFilterChanged;
 };
 
 char *qemuMonitorEscapeArg(const char *in);
@@ -285,6 +290,8 @@ int qemuMonitorEmitPMSuspendDisk(qemuMonitorPtr mon);
 int qemuMonitorEmitGuestPanic(qemuMonitorPtr mon);
 int qemuMonitorEmitDeviceDeleted(qemuMonitorPtr mon,
                                  const char *devAlias);
+int qemuMonitorEmitNicRxFilterChanged(qemuMonitorPtr mon,
+                                      const char *devAlias);
 
 int qemuMonitorStartCPUs(qemuMonitorPtr mon,
                          virConnectPtr conn);

src/qemu/qemu_monitor_json.c

@@ -81,6 +81,7 @@ static void qemuMonitorJSONHandleBalloonChange(qemuMonitorPtr mon, virJSONValueP
 static void qemuMonitorJSONHandlePMSuspendDisk(qemuMonitorPtr mon, virJSONValuePtr data);
 static void qemuMonitorJSONHandleGuestPanic(qemuMonitorPtr mon, virJSONValuePtr data);
 static void qemuMonitorJSONHandleDeviceDeleted(qemuMonitorPtr mon, virJSONValuePtr data);
+static void qemuMonitorJSONHandleNicRxFilterChanged(qemuMonitorPtr mon, virJSONValuePtr data);
 
 typedef struct {
     const char *type;
@@ -96,6 +97,7 @@ static qemuEventHandler eventHandlers[] = {
     { "DEVICE_DELETED", qemuMonitorJSONHandleDeviceDeleted, },
     { "DEVICE_TRAY_MOVED", qemuMonitorJSONHandleTrayChange, },
     { "GUEST_PANICKED", qemuMonitorJSONHandleGuestPanic, },
+    { "NIC_RX_FILTER_CHANGED", qemuMonitorJSONHandleNicRxFilterChanged, },
     { "POWERDOWN", qemuMonitorJSONHandlePowerdown, },
     { "RESET", qemuMonitorJSONHandleReset, },
     { "RESUME", qemuMonitorJSONHandleResume, },
@@ -1037,6 +1039,21 @@ qemuMonitorJSONHandleDeviceDeleted(qemuMonitorPtr mon, virJSONValuePtr data)
     qemuMonitorEmitDeviceDeleted(mon, device);
 }
 
+
+static void
+qemuMonitorJSONHandleNicRxFilterChanged(qemuMonitorPtr mon, virJSONValuePtr data)
+{
+    const char *name;
+
+    if (!(name = virJSONValueObjectGetString(data, "name"))) {
+        VIR_WARN("missing device in NIC_RX_FILTER_CHANGED event");
+        return;
+    }
+
+    qemuMonitorEmitNicRxFilterChanged(mon, name);
+}
+
+
 int
 qemuMonitorJSONHumanCommandWithFd(qemuMonitorPtr mon,
                                   const char *cmd_str,

src/qemu/qemu_process.c

@@ -1489,6 +1489,47 @@ qemuProcessHandleDeviceDeleted(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
 }
 
 
+static int
+qemuProcessHandleNicRxFilterChanged(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
+                                    virDomainObjPtr vm,
+                                    const char *devAlias,
+                                    void *opaque)
+{
+    virQEMUDriverPtr driver = opaque;
+    struct qemuProcessEvent *processEvent = NULL;
+    char *data;
+
+    virObjectLock(vm);
+
+    VIR_DEBUG("Device %s RX Filter changed in domain %p %s",
+              devAlias, vm, vm->def->name);
+
+    if (VIR_ALLOC(processEvent) < 0)
+        goto error;
+
+    processEvent->eventType = QEMU_PROCESS_EVENT_NIC_RX_FILTER_CHANGED;
+    if (VIR_STRDUP(data, devAlias) < 0)
+        goto error;
+    processEvent->data = data;
+    processEvent->vm = vm;
+
+    virObjectRef(vm);
+    if (virThreadPoolSendJob(driver->workerPool, 0, processEvent) < 0) {
+        ignore_value(virObjectUnref(vm));
+        goto error;
+    }
+
+ cleanup:
+    virObjectUnlock(vm);
+    return 0;
+ error:
+    if (processEvent)
+        VIR_FREE(processEvent->data);
+    VIR_FREE(processEvent);
+    goto cleanup;
+}
+
+
 static qemuMonitorCallbacks monitorCallbacks = {
     .eofNotify = qemuProcessHandleMonitorEOF,
     .errorNotify = qemuProcessHandleMonitorError,
@@ -1510,6 +1551,7 @@ static qemuMonitorCallbacks monitorCallbacks = {
     .domainPMSuspendDisk = qemuProcessHandlePMSuspendDisk,
     .domainGuestPanic = qemuProcessHandleGuestPanic,
     .domainDeviceDeleted = qemuProcessHandleDeviceDeleted,
+    .domainNicRxFilterChanged = qemuProcessHandleNicRxFilterChanged,
 };
 
 static int