Stop accessing driver->caps directly in QEMU driver

The 'driver->caps' pointer can be changed on the fly. Accessing
it currently requires the global driver lock. Isolate this
access in a single helper, so a future patch can relax the
locking constraints.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

src/qemu/qemu_command.c

@@ -4396,7 +4396,7 @@ qemuBuildCpuArgStr(const virQEMUDriverPtr driver,
                    bool *hasHwVirt,
                    bool migrating)
 {
-    const virCPUDefPtr host = driver->caps->host.cpu;
+    virCPUDefPtr host = NULL;
     virCPUDefPtr guest = NULL;
     virCPUDefPtr cpu = NULL;
     size_t ncpus = 0;
@@ -4408,9 +4408,15 @@ qemuBuildCpuArgStr(const virQEMUDriverPtr driver,
     int ret = -1;
     virBuffer buf = VIR_BUFFER_INITIALIZER;
     int i;
+    virCapsPtr caps = NULL;
 
     *hasHwVirt = false;
 
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
+
+    host = caps->host.cpu;
+
     if (def->os.arch == VIR_ARCH_I686)
         default_model = "qemu32";
     else
@@ -4595,7 +4601,7 @@ cleanup:
         cpuDataFree(host->arch, data);
     virCPUDefFree(guest);
     virCPUDefFree(cpu);
-
+    virObjectUnref(caps);
     return ret;
 
 no_memory:

src/qemu/qemu_conf.c

@@ -526,6 +526,106 @@ virQEMUDriverConfigPtr virQEMUDriverGetConfig(virQEMUDriverPtr driver)
     return virObjectRef(driver->config);
 }
 
+
+virCapsPtr virQEMUDriverCreateCapabilities(virQEMUDriverPtr driver)
+{
+    size_t i;
+    virCapsPtr caps;
+    virSecurityManagerPtr *sec_managers = NULL;
+    /* Security driver data */
+    const char *doi, *model;
+    virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+
+    /* Basic host arch / guest machine capabilities */
+    if (!(caps = virQEMUCapsInit(driver->qemuCapsCache))) {
+        virReportOOMError();
+        virObjectUnref(cfg);
+        return NULL;
+    }
+
+    if (cfg->allowDiskFormatProbing) {
+        caps->defaultDiskDriverName = NULL;
+        caps->defaultDiskDriverType = VIR_STORAGE_FILE_AUTO;
+    } else {
+        caps->defaultDiskDriverName = "qemu";
+        caps->defaultDiskDriverType = VIR_STORAGE_FILE_RAW;
+    }
+
+    qemuDomainSetPrivateDataHooks(caps);
+    qemuDomainSetNamespaceHooks(caps);
+
+    if (virGetHostUUID(caps->host.host_uuid)) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       "%s", _("cannot get the host uuid"));
+        goto err_exit;
+    }
+
+    /* access sec drivers and create a sec model for each one */
+    sec_managers = virSecurityManagerGetNested(driver->securityManager);
+    if (sec_managers == NULL) {
+        goto err_exit;
+    }
+
+    /* calculate length */
+    for (i = 0; sec_managers[i]; i++)
+        ;
+    caps->host.nsecModels = i;
+
+    if (VIR_ALLOC_N(caps->host.secModels, caps->host.nsecModels) < 0)
+        goto no_memory;
+
+    for (i = 0; sec_managers[i]; i++) {
+        doi = virSecurityManagerGetDOI(sec_managers[i]);
+        model = virSecurityManagerGetModel(sec_managers[i]);
+        if (!(caps->host.secModels[i].model = strdup(model)))
+            goto no_memory;
+        if (!(caps->host.secModels[i].doi = strdup(doi)))
+            goto no_memory;
+        VIR_DEBUG("Initialized caps for security driver \"%s\" with "
+                  "DOI \"%s\"", model, doi);
+    }
+    VIR_FREE(sec_managers);
+
+    virObjectUnref(cfg);
+    return caps;
+
+no_memory:
+    virReportOOMError();
+err_exit:
+    VIR_FREE(sec_managers);
+    virObjectUnref(caps);
+    virObjectUnref(cfg);
+    return NULL;
+}
+
+
+/**
+ * virQEMUDriverGetCapabilities:
+ *
+ * Get a reference to the virCapsPtr instance for the
+ * driver. If @refresh is true, the capabilities will be
+ * rebuilt first
+ *
+ * The caller must release the reference with virObjetUnref
+ *
+ * Returns: a reference to a virCapsPtr instance or NULL
+ */
+virCapsPtr virQEMUDriverGetCapabilities(virQEMUDriverPtr driver,
+                                        bool refresh)
+{
+    if (refresh) {
+        virCapsPtr caps = NULL;
+        if ((caps = virQEMUDriverCreateCapabilities(driver)) == NULL)
+            return NULL;
+
+        virObjectUnref(driver->caps);
+        driver->caps = caps;
+    }
+
+    return virObjectRef(driver->caps);
+}
+
+
 static void
 qemuDriverCloseCallbackFree(void *payload,
                             const void *name ATTRIBUTE_UNUSED)

src/qemu/qemu_conf.h

@@ -183,7 +183,9 @@ struct _virQEMUDriver {
     /* Immutable pointer, lockless APIs. Pointless abstraction */
     ebtablesContext *ebtables;
 
-    /* Require lock while using. Unsafe. XXX */
+    /* Require lock to get a reference on the object,
+     * lockless access thereafter
+     */
     virCapsPtr caps;
 
     /* Immutable pointer, self-locking APIs */
@@ -244,6 +246,10 @@ int virQEMUDriverConfigLoadFile(virQEMUDriverConfigPtr cfg,
 
 virQEMUDriverConfigPtr virQEMUDriverGetConfig(virQEMUDriverPtr driver);
 
+virCapsPtr virQEMUDriverCreateCapabilities(virQEMUDriverPtr driver);
+virCapsPtr virQEMUDriverGetCapabilities(virQEMUDriverPtr driver,
+                                        bool refresh);
+
 struct qemuDomainDiskInfo {
     bool removable;
     bool locked;

src/qemu/qemu_domain.c

@@ -664,13 +664,19 @@ static void
 qemuDomainObjSaveJob(virQEMUDriverPtr driver, virDomainObjPtr obj)
 {
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virCapsPtr caps = NULL;
+
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
 
     if (virDomainObjIsActive(obj)) {
-        if (virDomainSaveStatus(driver->caps, cfg->stateDir, obj) < 0)
+        if (virDomainSaveStatus(caps, cfg->stateDir, obj) < 0)
             VIR_WARN("Failed to save status on vm %s", obj->def->name);
     }
 
+cleanup:
     virObjectUnref(cfg);
+    virObjectUnref(caps);
 }
 
 void
@@ -1244,21 +1250,24 @@ qemuDomainDefFormatBuf(virQEMUDriverPtr driver,
     virCPUDefPtr def_cpu = def->cpu;
     virDomainControllerDefPtr *controllers = NULL;
     int ncontrollers = 0;
+    virCapsPtr caps = NULL;
+
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
 
     /* Update guest CPU requirements according to host CPU */
     if ((flags & VIR_DOMAIN_XML_UPDATE_CPU) &&
         def_cpu &&
         (def_cpu->mode != VIR_CPU_MODE_CUSTOM || def_cpu->model)) {
-        if (!driver->caps ||
+        if (!caps->host.cpu ||
-            !driver->caps->host.cpu ||
+            !caps->host.cpu->model) {
-            !driver->caps->host.cpu->model) {
             virReportError(VIR_ERR_OPERATION_FAILED,
                            "%s", _("cannot get host CPU capabilities"));
             goto cleanup;
         }
 
         if (!(cpu = virCPUDefCopy(def_cpu)) ||
-            cpuUpdate(cpu, driver->caps->host.cpu) < 0)
+            cpuUpdate(cpu, caps->host.cpu) < 0)
             goto cleanup;
         def->cpu = cpu;
     }
@@ -1310,6 +1319,7 @@ cleanup:
         def->controllers = controllers;
         def->ncontrollers = ncontrollers;
     }
+    virObjectUnref(caps);
     return ret;
 }
 
@@ -1888,16 +1898,22 @@ qemuDomainSetFakeReboot(virQEMUDriverPtr driver,
 {
     qemuDomainObjPrivatePtr priv = vm->privateData;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virCapsPtr caps = NULL;
+
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
 
     if (priv->fakeReboot == value)
-        return;
+        goto cleanup;
 
     priv->fakeReboot = value;
 
-    if (virDomainSaveStatus(driver->caps, cfg->stateDir, vm) < 0)
+    if (virDomainSaveStatus(caps, cfg->stateDir, vm) < 0)
         VIR_WARN("Failed to save status on vm %s", vm->def->name);
 
+cleanup:
     virObjectUnref(cfg);
+    virObjectUnref(caps);
 }
 
 int

src/qemu/qemu_migration.c

@@ -742,9 +742,13 @@ qemuMigrationCookieXMLParse(qemuMigrationCookiePtr mig,
                             unsigned int flags)
 {
     char uuidstr[VIR_UUID_STRING_BUFLEN];
-    char *tmp;
+    char *tmp = NULL;
     xmlNodePtr *nodes = NULL;
     int i, n;
+    virCapsPtr caps = NULL;
+
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto error;
 
     /* We don't store the uuid, name, hostname, or hostuuid
      * values. We just compare them to local data to do some
@@ -870,7 +874,7 @@ qemuMigrationCookieXMLParse(qemuMigrationCookiePtr mig,
                            n);
             goto error;
         }
-        mig->persistent = virDomainDefParseNode(driver->caps, doc, nodes[0],
+        mig->persistent = virDomainDefParseNode(caps, doc, nodes[0],
                                                 -1, VIR_DOMAIN_XML_INACTIVE);
         if (!mig->persistent) {
             /* virDomainDefParseNode already reported
@@ -885,11 +889,13 @@ qemuMigrationCookieXMLParse(qemuMigrationCookiePtr mig,
         (!(mig->network = qemuMigrationCookieNetworkXMLParse(ctxt))))
         goto error;
 
+    virObjectUnref(caps);
     return 0;
 
 error:
     VIR_FREE(tmp);
     VIR_FREE(nodes);
+    virObjectUnref(caps);
     return -1;
 }
 
@@ -1434,12 +1440,16 @@ char *qemuMigrationBegin(virQEMUDriverPtr driver,
     qemuMigrationCookiePtr mig = NULL;
     virDomainDefPtr def = NULL;
     qemuDomainObjPrivatePtr priv = vm->privateData;
+    virCapsPtr caps = NULL;
 
     VIR_DEBUG("driver=%p, vm=%p, xmlin=%s, dname=%s,"
               " cookieout=%p, cookieoutlen=%p, flags=%lx",
               driver, vm, NULLSTR(xmlin), NULLSTR(dname),
               cookieout, cookieoutlen, flags);
 
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
+
     /* Only set the phase if we are inside QEMU_ASYNC_JOB_MIGRATION_OUT.
      * Otherwise we will start the async job later in the perform phase losing
      * change protection.
@@ -1484,7 +1494,7 @@ char *qemuMigrationBegin(virQEMUDriverPtr driver,
     }
 
     if (xmlin) {
-        if (!(def = virDomainDefParseString(driver->caps, xmlin,
+        if (!(def = virDomainDefParseString(caps, xmlin,
                                             QEMU_EXPECTED_VIRT_TYPES,
                                             VIR_DOMAIN_XML_INACTIVE)))
             goto cleanup;
@@ -1505,6 +1515,7 @@ char *qemuMigrationBegin(virQEMUDriverPtr driver,
 
 cleanup:
     qemuMigrationCookieFree(mig);
+    virObjectUnref(caps);
     virDomainDefFree(def);
     return rv;
 }
@@ -1555,6 +1566,7 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
     char *origname = NULL;
     char *xmlout = NULL;
     unsigned int cookieFlags;
+    virCapsPtr caps = NULL;
 
     if (virTimeMillisNow(&now) < 0)
         return -1;
@@ -1581,7 +1593,10 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
         }
     }
 
-    if (!(def = virDomainDefParseString(driver->caps, dom_xml,
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
+
+    if (!(def = virDomainDefParseString(caps, dom_xml,
                                         QEMU_EXPECTED_VIRT_TYPES,
                                         VIR_DOMAIN_XML_INACTIVE)))
         goto cleanup;
@@ -1622,7 +1637,7 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
                 virDomainDefPtr newdef;
 
                 VIR_DEBUG("Using hook-filtered domain XML: %s", xmlout);
-                newdef = virDomainDefParseString(driver->caps, xmlout,
+                newdef = virDomainDefParseString(caps, xmlout,
                                                  QEMU_EXPECTED_VIRT_TYPES,
                                                  VIR_DOMAIN_XML_INACTIVE);
                 if (!newdef)
@@ -1640,7 +1655,7 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
     }
 
     if (!(vm = virDomainObjListAdd(driver->domains,
-                                   driver->caps,
+                                   caps,
                                    def,
                                    VIR_DOMAIN_OBJ_LIST_ADD_LIVE |
                                    VIR_DOMAIN_OBJ_LIST_ADD_CHECK_LIVE,
@@ -1760,6 +1775,7 @@ cleanup:
     if (event)
         qemuDomainEventQueue(driver, event);
     qemuMigrationCookieFree(mig);
+    virObjectUnref(caps);
     return ret;
 
 endjob:
@@ -3323,12 +3339,16 @@ qemuMigrationFinish(virQEMUDriverPtr driver,
     int cookie_flags = 0;
     qemuDomainObjPrivatePtr priv = vm->privateData;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virCapsPtr caps = NULL;
 
     VIR_DEBUG("driver=%p, dconn=%p, vm=%p, cookiein=%s, cookieinlen=%d, "
               "cookieout=%p, cookieoutlen=%p, flags=%lx, retcode=%d",
               driver, dconn, vm, NULLSTR(cookiein), cookieinlen,
               cookieout, cookieoutlen, flags, retcode);
 
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
+
     if (!qemuMigrationJobIsActive(vm, QEMU_ASYNC_JOB_MIGRATION_IN))
         goto cleanup;
 
@@ -3379,7 +3399,7 @@ qemuMigrationFinish(virQEMUDriverPtr driver,
             if (mig->persistent)
                 vm->newDef = vmdef = mig->persistent;
             else
-                vmdef = virDomainObjGetPersistentDef(driver->caps, vm);
+                vmdef = virDomainObjGetPersistentDef(caps, vm);
             if (!vmdef || virDomainSaveConfig(cfg->configDir, vmdef) < 0) {
                 /* Hmpf.  Migration was successful, but making it persistent
                  * was not.  If we report successful, then when this domain
@@ -3474,7 +3494,7 @@ qemuMigrationFinish(virQEMUDriverPtr driver,
         }
 
         if (virDomainObjIsActive(vm) &&
-            virDomainSaveStatus(driver->caps, cfg->stateDir, vm) < 0) {
+            virDomainSaveStatus(caps, cfg->stateDir, vm) < 0) {
             VIR_WARN("Failed to save status on vm %s", vm->def->name);
             goto endjob;
         }
@@ -3513,6 +3533,7 @@ cleanup:
         virSetError(orig_err);
         virFreeError(orig_err);
     }
+    virObjectUnref(caps);
     virObjectUnref(cfg);
     return dom;
 }
@@ -3530,6 +3551,7 @@ int qemuMigrationConfirm(virQEMUDriverPtr driver,
     virDomainEventPtr event = NULL;
     int rv = -1;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virCapsPtr caps = NULL;
 
     VIR_DEBUG("driver=%p, conn=%p, vm=%p, cookiein=%s, cookieinlen=%d, "
               "flags=%x, retcode=%d",
@@ -3538,6 +3560,9 @@ int qemuMigrationConfirm(virQEMUDriverPtr driver,
 
     virCheckFlags(QEMU_MIGRATION_FLAGS, -1);
 
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
+
     qemuMigrationJobSetPhase(driver, vm,
                              retcode == 0
                              ? QEMU_MIGRATION_PHASE_CONFIRM3
@@ -3578,7 +3603,7 @@ int qemuMigrationConfirm(virQEMUDriverPtr driver,
         event = virDomainEventNewFromObj(vm,
                                          VIR_DOMAIN_EVENT_RESUMED,
                                          VIR_DOMAIN_EVENT_RESUMED_MIGRATED);
-        if (virDomainSaveStatus(driver->caps, cfg->stateDir, vm) < 0) {
+        if (virDomainSaveStatus(caps, cfg->stateDir, vm) < 0) {
             VIR_WARN("Failed to save status on vm %s", vm->def->name);
             goto cleanup;
         }
@@ -3591,6 +3616,7 @@ done:
 cleanup:
     if (event)
         qemuDomainEventQueue(driver, event);
+    virObjectUnref(caps);
     virObjectUnref(cfg);
     return rv;
 }

src/qemu/qemu_process.c

@@ -660,9 +660,13 @@ qemuProcessHandleShutdown(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
     qemuDomainObjPrivatePtr priv;
     virDomainEventPtr event = NULL;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virCapsPtr caps = NULL;
 
     VIR_DEBUG("vm=%p", vm);
 
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
+
     virObjectLock(vm);
 
     priv = vm->privateData;
@@ -686,7 +690,7 @@ qemuProcessHandleShutdown(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
                                      VIR_DOMAIN_EVENT_SHUTDOWN,
                                      VIR_DOMAIN_EVENT_SHUTDOWN_FINISHED);
 
-    if (virDomainSaveStatus(driver->caps, cfg->stateDir, vm) < 0) {
+    if (virDomainSaveStatus(caps, cfg->stateDir, vm) < 0) {
         VIR_WARN("Unable to save status on vm %s after state change",
                  vm->def->name);
     }
@@ -698,12 +702,13 @@ qemuProcessHandleShutdown(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
 
 unlock:
     virObjectUnlock(vm);
-
+cleanup:
     if (event) {
         qemuDriverLock(driver);
         qemuDomainEventQueue(driver, event);
         qemuDriverUnlock(driver);
     }
+    virObjectUnref(caps);
     virObjectUnref(cfg);
 
     return 0;
@@ -717,6 +722,10 @@ qemuProcessHandleStop(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
     virQEMUDriverPtr driver = qemu_driver;
     virDomainEventPtr event = NULL;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virCapsPtr caps = NULL;
+
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
 
     virObjectLock(vm);
     if (virDomainObjGetState(vm, NULL) == VIR_DOMAIN_RUNNING) {
@@ -740,7 +749,7 @@ qemuProcessHandleStop(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
             VIR_WARN("Unable to release lease on %s", vm->def->name);
         VIR_DEBUG("Preserving lock state '%s'", NULLSTR(priv->lockState));
 
-        if (virDomainSaveStatus(driver->caps, cfg->stateDir, vm) < 0) {
+        if (virDomainSaveStatus(caps, cfg->stateDir, vm) < 0) {
             VIR_WARN("Unable to save status on vm %s after state change",
                      vm->def->name);
         }
@@ -749,11 +758,13 @@ qemuProcessHandleStop(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
 unlock:
     virObjectUnlock(vm);
 
+cleanup:
     if (event) {
         qemuDriverLock(driver);
         qemuDomainEventQueue(driver, event);
         qemuDriverUnlock(driver);
     }
+    virObjectUnref(caps);
     virObjectUnref(cfg);
 
     return 0;
@@ -767,6 +778,10 @@ qemuProcessHandleResume(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
     virQEMUDriverPtr driver = qemu_driver;
     virDomainEventPtr event = NULL;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virCapsPtr caps = NULL;
+
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
 
     virObjectLock(vm);
     if (virDomainObjGetState(vm, NULL) == VIR_DOMAIN_PAUSED) {
@@ -797,7 +812,7 @@ qemuProcessHandleResume(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
         }
         VIR_FREE(priv->lockState);
 
-        if (virDomainSaveStatus(driver->caps, cfg->stateDir, vm) < 0) {
+        if (virDomainSaveStatus(caps, cfg->stateDir, vm) < 0) {
             VIR_WARN("Unable to save status on vm %s after state change",
                      vm->def->name);
         }
@@ -805,12 +820,13 @@ qemuProcessHandleResume(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
 
 unlock:
     virObjectUnlock(vm);
-
+cleanup:
     if (event) {
         qemuDriverLock(driver);
         qemuDomainEventQueue(driver, event);
         qemuDriverUnlock(driver);
     }
+    virObjectUnref(caps);
     virObjectUnref(cfg);
     return 0;
 }
@@ -822,8 +838,12 @@ qemuProcessHandleRTCChange(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
                            long long offset)
 {
     virQEMUDriverPtr driver = qemu_driver;
-    virDomainEventPtr event;
+    virDomainEventPtr event = NULL;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virCapsPtr caps = NULL;
+
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
 
     virObjectLock(vm);
     event = virDomainEventRTCChangeNewFromObj(vm, offset);
@@ -831,17 +851,18 @@ qemuProcessHandleRTCChange(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
     if (vm->def->clock.offset == VIR_DOMAIN_CLOCK_OFFSET_VARIABLE)
         vm->def->clock.data.variable.adjustment = offset;
 
-    if (virDomainSaveStatus(driver->caps, cfg->stateDir, vm) < 0)
+    if (virDomainSaveStatus(caps, cfg->stateDir, vm) < 0)
         VIR_WARN("unable to save domain status with RTC change");
 
     virObjectUnlock(vm);
 
+cleanup:
     if (event) {
         qemuDriverLock(driver);
         qemuDomainEventQueue(driver, event);
         qemuDriverUnlock(driver);
     }
-
+    virObjectUnref(caps);
     virObjectUnref(cfg);
     return 0;
 }
@@ -856,6 +877,10 @@ qemuProcessHandleWatchdog(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
     virDomainEventPtr watchdogEvent = NULL;
     virDomainEventPtr lifecycleEvent = NULL;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virCapsPtr caps = NULL;
+
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
 
     virObjectLock(vm);
     watchdogEvent = virDomainEventWatchdogNewFromObj(vm, action);
@@ -875,7 +900,7 @@ qemuProcessHandleWatchdog(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
             VIR_WARN("Unable to release lease on %s", vm->def->name);
         VIR_DEBUG("Preserving lock state '%s'", NULLSTR(priv->lockState));
 
-        if (virDomainSaveStatus(driver->caps, cfg->stateDir, vm) < 0) {
+        if (virDomainSaveStatus(caps, cfg->stateDir, vm) < 0) {
             VIR_WARN("Unable to save status on vm %s after watchdog event",
                      vm->def->name);
         }
@@ -903,6 +928,7 @@ qemuProcessHandleWatchdog(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
     if (vm)
         virObjectUnlock(vm);
 
+cleanup:
     if (watchdogEvent || lifecycleEvent) {
         qemuDriverLock(driver);
         if (watchdogEvent)
@@ -912,6 +938,7 @@ qemuProcessHandleWatchdog(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
         qemuDriverUnlock(driver);
     }
 
+    virObjectUnref(caps);
     virObjectUnref(cfg);
     return 0;
 }
@@ -932,6 +959,10 @@ qemuProcessHandleIOError(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
     const char *devAlias;
     virDomainDiskDefPtr disk;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virCapsPtr caps = NULL;
+
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
 
     virObjectLock(vm);
     disk = qemuProcessFindDomainDiskByAlias(vm, diskAlias);
@@ -962,11 +993,12 @@ qemuProcessHandleIOError(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
             VIR_WARN("Unable to release lease on %s", vm->def->name);
         VIR_DEBUG("Preserving lock state '%s'", NULLSTR(priv->lockState));
 
-        if (virDomainSaveStatus(driver->caps, cfg->stateDir, vm) < 0)
+        if (virDomainSaveStatus(caps, cfg->stateDir, vm) < 0)
             VIR_WARN("Unable to save status on vm %s after IO error", vm->def->name);
     }
     virObjectUnlock(vm);
 
+cleanup:
     if (ioErrorEvent || ioErrorEvent2 || lifecycleEvent) {
         qemuDriverLock(driver);
         if (ioErrorEvent)
@@ -977,7 +1009,7 @@ qemuProcessHandleIOError(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
             qemuDomainEventQueue(driver, lifecycleEvent);
         qemuDriverUnlock(driver);
     }
-
+    virObjectUnref(caps);
     virObjectUnref(cfg);
     return 0;
 }
@@ -1134,6 +1166,10 @@ qemuProcessHandleTrayChange(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
     virDomainEventPtr event = NULL;
     virDomainDiskDefPtr disk;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virCapsPtr caps = NULL;
+
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
 
     virObjectLock(vm);
     disk = qemuProcessFindDomainDiskByAlias(vm, devAlias);
@@ -1148,19 +1184,20 @@ qemuProcessHandleTrayChange(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
         else if (reason == VIR_DOMAIN_EVENT_TRAY_CHANGE_CLOSE)
             disk->tray_status = VIR_DOMAIN_DISK_TRAY_CLOSED;
 
-        if (virDomainSaveStatus(driver->caps, cfg->stateDir, vm) < 0) {
+        if (virDomainSaveStatus(caps, cfg->stateDir, vm) < 0) {
             VIR_WARN("Unable to save status on vm %s after tray moved event",
                      vm->def->name);
         }
     }
 
     virObjectUnlock(vm);
-
+cleanup:
     if (event) {
         qemuDriverLock(driver);
         qemuDomainEventQueue(driver, event);
         qemuDriverUnlock(driver);
     }
+    virObjectUnref(caps);
     virObjectUnref(cfg);
     return 0;
 }
@@ -1173,6 +1210,10 @@ qemuProcessHandlePMWakeup(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
     virDomainEventPtr event = NULL;
     virDomainEventPtr lifecycleEvent = NULL;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virCapsPtr caps = NULL;
+
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
 
     virObjectLock(vm);
     event = virDomainEventPMWakeupNewFromObj(vm);
@@ -1190,7 +1231,7 @@ qemuProcessHandlePMWakeup(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
                                                   VIR_DOMAIN_EVENT_STARTED,
                                                   VIR_DOMAIN_EVENT_STARTED_WAKEUP);
 
-        if (virDomainSaveStatus(driver->caps, cfg->stateDir, vm) < 0) {
+        if (virDomainSaveStatus(caps, cfg->stateDir, vm) < 0) {
             VIR_WARN("Unable to save status on vm %s after wakeup event",
                      vm->def->name);
         }
@@ -1198,6 +1239,7 @@ qemuProcessHandlePMWakeup(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
 
     virObjectUnlock(vm);
 
+cleanup:
     if (event || lifecycleEvent) {
         qemuDriverLock(driver);
         if (event)
@@ -1206,7 +1248,7 @@ qemuProcessHandlePMWakeup(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
             qemuDomainEventQueue(driver, lifecycleEvent);
         qemuDriverUnlock(driver);
     }
-
+    virObjectUnref(caps);
     virObjectUnref(cfg);
     return 0;
 }
@@ -1219,6 +1261,10 @@ qemuProcessHandlePMSuspend(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
     virDomainEventPtr event = NULL;
     virDomainEventPtr lifecycleEvent = NULL;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virCapsPtr caps = NULL;
+
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
 
     virObjectLock(vm);
     event = virDomainEventPMSuspendNewFromObj(vm);
@@ -1235,7 +1281,7 @@ qemuProcessHandlePMSuspend(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
                                      VIR_DOMAIN_EVENT_PMSUSPENDED,
                                      VIR_DOMAIN_EVENT_PMSUSPENDED_MEMORY);
 
-        if (virDomainSaveStatus(driver->caps, cfg->stateDir, vm) < 0) {
+        if (virDomainSaveStatus(caps, cfg->stateDir, vm) < 0) {
             VIR_WARN("Unable to save status on vm %s after suspend event",
                      vm->def->name);
         }
@@ -1246,6 +1292,7 @@ qemuProcessHandlePMSuspend(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
 
     virObjectUnlock(vm);
 
+cleanup:
     if (event || lifecycleEvent) {
         qemuDriverLock(driver);
         if (event)
@@ -1254,6 +1301,7 @@ qemuProcessHandlePMSuspend(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
             qemuDomainEventQueue(driver, lifecycleEvent);
         qemuDriverUnlock(driver);
     }
+    virObjectUnref(caps);
     virObjectUnref(cfg);
     return 0;
 }
@@ -1264,8 +1312,12 @@ qemuProcessHandleBalloonChange(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
                                unsigned long long actual)
 {
     virQEMUDriverPtr driver = qemu_driver;
-    virDomainEventPtr event;
+    virDomainEventPtr event = NULL;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virCapsPtr caps = NULL;
+
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
 
     virObjectLock(vm);
     event = virDomainEventBalloonChangeNewFromObj(vm, actual);
@@ -1274,17 +1326,18 @@ qemuProcessHandleBalloonChange(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
               vm->def->mem.cur_balloon, actual);
     vm->def->mem.cur_balloon = actual;
 
-    if (virDomainSaveStatus(driver->caps, cfg->stateDir, vm) < 0)
+    if (virDomainSaveStatus(caps, cfg->stateDir, vm) < 0)
         VIR_WARN("unable to save domain status with balloon change");
 
     virObjectUnlock(vm);
 
+cleanup:
     if (event) {
         qemuDriverLock(driver);
         qemuDomainEventQueue(driver, event);
         qemuDriverUnlock(driver);
     }
-
+    virObjectUnref(caps);
     virObjectUnref(cfg);
     return 0;
 }
@@ -1297,6 +1350,10 @@ qemuProcessHandlePMSuspendDisk(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
     virDomainEventPtr event = NULL;
     virDomainEventPtr lifecycleEvent = NULL;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virCapsPtr caps = NULL;
+
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
 
     virObjectLock(vm);
     event = virDomainEventPMSuspendDiskNewFromObj(vm);
@@ -1313,7 +1370,7 @@ qemuProcessHandlePMSuspendDisk(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
                                      VIR_DOMAIN_EVENT_PMSUSPENDED,
                                      VIR_DOMAIN_EVENT_PMSUSPENDED_DISK);
 
-        if (virDomainSaveStatus(driver->caps,cfg->stateDir, vm) < 0) {
+        if (virDomainSaveStatus(caps, cfg->stateDir, vm) < 0) {
             VIR_WARN("Unable to save status on vm %s after suspend event",
                      vm->def->name);
         }
@@ -1324,6 +1381,7 @@ qemuProcessHandlePMSuspendDisk(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
 
     virObjectUnlock(vm);
 
+cleanup:
     if (event || lifecycleEvent) {
         qemuDriverLock(driver);
         if (event)
@@ -1332,7 +1390,7 @@ qemuProcessHandlePMSuspendDisk(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
             qemuDomainEventQueue(driver, lifecycleEvent);
         qemuDriverUnlock(driver);
     }
-
+    virObjectUnref(caps);
     virObjectUnref(cfg);
 
     return 0;
@@ -2029,6 +2087,7 @@ qemuPrepareCpumap(virQEMUDriverPtr driver,
 {
     int i, hostcpus, maxcpu = QEMUD_CPUMASK_LEN;
     virBitmapPtr cpumap = NULL;
+    virCapsPtr caps = NULL;
 
     /* setaffinity fails if you set bits for CPUs which
      * aren't present, so we have to limit ourselves */
@@ -2044,24 +2103,33 @@ qemuPrepareCpumap(virQEMUDriverPtr driver,
     }
 
     if (nodemask) {
-        for (i = 0; i < driver->caps->host.nnumaCell; i++) {
+        if (!(caps = virQEMUDriverGetCapabilities(driver, false))) {
+            virBitmapFree(cpumap);
+            cpumap = NULL;
+            goto cleanup;
+        }
+
+        for (i = 0; i < caps->host.nnumaCell; i++) {
             int j;
-            int cur_ncpus = driver->caps->host.numaCell[i]->ncpus;
+            int cur_ncpus = caps->host.numaCell[i]->ncpus;
             bool result;
             if (virBitmapGetBit(nodemask, i, &result) < 0) {
                 virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                                _("Failed to convert nodeset to cpuset"));
                 virBitmapFree(cpumap);
-                return NULL;
+                cpumap = NULL;
+                goto cleanup;
             }
             if (result) {
                 for (j = 0; j < cur_ncpus; j++)
                     ignore_value(virBitmapSetBit(cpumap,
-                                                 driver->caps->host.numaCell[i]->cpus[j].id));
+                                                 caps->host.numaCell[i]->cpus[j].id));
             }
         }
     }
 
+cleanup:
+    virObjectUnref(caps);
     return cpumap;
 }
 
@@ -3185,6 +3253,7 @@ qemuProcessReconnect(void *opaque)
     int state;
     int reason;
     virQEMUDriverConfigPtr cfg;
+    virCapsPtr caps = NULL;
 
     memcpy(&oldjob, &data->oldjob, sizeof(oldjob));
 
@@ -3205,6 +3274,9 @@ qemuProcessReconnect(void *opaque)
      * deleted if qemuConnectMonitor() failed */
     virObjectRef(obj);
 
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto error;
+
     /* XXX check PID liveliness & EXE path */
     if (qemuConnectMonitor(driver, obj) < 0)
         goto error;
@@ -3275,7 +3347,7 @@ qemuProcessReconnect(void *opaque)
         goto error;
 
     /* update domain state XML with possibly updated state in virDomainObj */
-    if (virDomainSaveStatus(driver->caps, cfg->stateDir, obj) < 0)
+    if (virDomainSaveStatus(caps, cfg->stateDir, obj) < 0)
         goto error;
 
     /* Run an hook to allow admins to do some magic */
@@ -3310,6 +3382,7 @@ endjob:
 
     virConnectClose(conn);
     virObjectUnref(cfg);
+    virObjectUnref(caps);
 
     return;
 
@@ -3348,8 +3421,8 @@ error:
         }
     }
     qemuDriverUnlock(driver);
-
     virConnectClose(conn);
+    virObjectUnref(caps);
     virObjectUnref(cfg);
 }
 
@@ -3550,6 +3623,7 @@ int qemuProcessStart(virConnectPtr conn,
     virBitmapPtr nodemask = NULL;
     unsigned int stop_flags;
     virQEMUDriverConfigPtr cfg;
+    virCapsPtr caps = NULL;
 
     /* Okay, these are just internal flags,
      * but doesn't hurt to check */
@@ -3578,12 +3652,15 @@ int qemuProcessStart(virConnectPtr conn,
         return -1;
     }
 
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
+
     /* Do this upfront, so any part of the startup process can add
      * runtime state to vm->def that won't be persisted. This let's us
      * report implicit runtime defaults in the XML, like vnc listen/socket
      */
     VIR_DEBUG("Setting current domain def as transient");
-    if (virDomainObjSetDefTransient(driver->caps, vm, true) < 0)
+    if (virDomainObjSetDefTransient(caps, vm, true) < 0)
         goto cleanup;
 
     vm->def->id = qemuDriverAllocateID(driver);
@@ -3925,7 +4002,7 @@ int qemuProcessStart(virConnectPtr conn,
     }
 
     VIR_DEBUG("Writing early domain status to disk");
-    if (virDomainSaveStatus(driver->caps, cfg->stateDir, vm) < 0) {
+    if (virDomainSaveStatus(caps, cfg->stateDir, vm) < 0) {
         goto cleanup;
     }
 
@@ -4076,7 +4153,7 @@ int qemuProcessStart(virConnectPtr conn,
         goto cleanup;
 
     VIR_DEBUG("Writing domain status to disk");
-    if (virDomainSaveStatus(driver->caps, cfg->stateDir, vm) < 0)
+    if (virDomainSaveStatus(caps, cfg->stateDir, vm) < 0)
         goto cleanup;
 
     /* finally we can call the 'started' hook script if any */
@@ -4099,6 +4176,7 @@ int qemuProcessStart(virConnectPtr conn,
     virCommandFree(cmd);
     VIR_FORCE_CLOSE(logfile);
     virObjectUnref(cfg);
+    virObjectUnref(caps);
 
     return 0;
 
@@ -4112,6 +4190,7 @@ cleanup:
     VIR_FORCE_CLOSE(logfile);
     qemuProcessStop(driver, vm, VIR_DOMAIN_SHUTOFF_FAILED, stop_flags);
     virObjectUnref(cfg);
+    virObjectUnref(caps);
 
     return -1;
 }
@@ -4420,6 +4499,7 @@ int qemuProcessAttach(virConnectPtr conn ATTRIBUTE_UNUSED,
     virSecurityManagerPtr* sec_managers = NULL;
     const char *model;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virCapsPtr caps = NULL;
 
     VIR_DEBUG("Beginning VM attach process");
 
@@ -4430,12 +4510,15 @@ int qemuProcessAttach(virConnectPtr conn ATTRIBUTE_UNUSED,
         return -1;
     }
 
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
+
     /* Do this upfront, so any part of the startup process can add
      * runtime state to vm->def that won't be persisted. This let's us
      * report implicit runtime defaults in the XML, like vnc listen/socket
      */
     VIR_DEBUG("Setting current domain def as transient");
-    if (virDomainObjSetDefTransient(driver->caps, vm, true) < 0)
+    if (virDomainObjSetDefTransient(caps, vm, true) < 0)
         goto cleanup;
 
     vm->def->id = qemuDriverAllocateID(driver);
@@ -4580,7 +4663,7 @@ int qemuProcessAttach(virConnectPtr conn ATTRIBUTE_UNUSED,
         virDomainObjSetState(vm, VIR_DOMAIN_PAUSED, reason);
 
     VIR_DEBUG("Writing domain status to disk");
-    if (virDomainSaveStatus(driver->caps, cfg->stateDir, vm) < 0)
+    if (virDomainSaveStatus(caps, cfg->stateDir, vm) < 0)
         goto cleanup;
 
     /* Run an hook to allow admins to do some magic */
@@ -4604,6 +4687,7 @@ int qemuProcessAttach(virConnectPtr conn ATTRIBUTE_UNUSED,
     VIR_FREE(seclabel);
     VIR_FREE(sec_managers);
     virObjectUnref(cfg);
+    virObjectUnref(caps);
 
     return 0;
 
@@ -4618,6 +4702,7 @@ cleanup:
     VIR_FREE(sec_managers);
     virDomainChrSourceDefFree(monConfig);
     virObjectUnref(cfg);
+    virObjectUnref(caps);
     return -1;
 }