1be8d8537SStefan Hajnoczi /* 2be8d8537SStefan Hajnoczi * Event loop thread 3be8d8537SStefan Hajnoczi * 4c3033fd3SEric Blake * Copyright Red Hat Inc., 2013, 2020 5be8d8537SStefan Hajnoczi * 6be8d8537SStefan Hajnoczi * Authors: 7be8d8537SStefan Hajnoczi * Stefan Hajnoczi <stefanha@redhat.com> 8be8d8537SStefan Hajnoczi * 9be8d8537SStefan Hajnoczi * This work is licensed under the terms of the GNU GPL, version 2 or later. 10be8d8537SStefan Hajnoczi * See the COPYING file in the top-level directory. 11be8d8537SStefan Hajnoczi * 12be8d8537SStefan Hajnoczi */ 13be8d8537SStefan Hajnoczi 14d38ea87aSPeter Maydell #include "qemu/osdep.h" 15be8d8537SStefan Hajnoczi #include "qom/object.h" 16be8d8537SStefan Hajnoczi #include "qom/object_interfaces.h" 17be8d8537SStefan Hajnoczi #include "qemu/module.h" 18be8d8537SStefan Hajnoczi #include "block/aio.h" 19d16341faSPaolo Bonzini #include "block/block.h" 20be8d8537SStefan Hajnoczi #include "sysemu/iothread.h" 21e688df6bSMarkus Armbruster #include "qapi/error.h" 22112ed241SMarkus Armbruster #include "qapi/qapi-commands-misc.h" 232f78e491SChrysostomos Nanakos #include "qemu/error-report.h" 24ab28bd23SPaolo Bonzini #include "qemu/rcu.h" 25e4370165SPaolo Bonzini #include "qemu/main-loop.h" 26be8d8537SStefan Hajnoczi 27be8d8537SStefan Hajnoczi typedef ObjectClass IOThreadClass; 28be8d8537SStefan Hajnoczi 298110fa1dSEduardo Habkost DECLARE_CLASS_CHECKERS(IOThreadClass, IOTHREAD, 308110fa1dSEduardo Habkost TYPE_IOTHREAD) 31be8d8537SStefan Hajnoczi 3290c558beSPeter Xu #ifdef CONFIG_POSIX 33cdd7abfdSStefan Hajnoczi /* Benchmark results from 2016 on NVMe SSD drives show max polling times around 34cdd7abfdSStefan Hajnoczi * 16-32 microseconds yield IOPS improvements for both iodepth=1 and iodepth=32 35cdd7abfdSStefan Hajnoczi * workloads. 36cdd7abfdSStefan Hajnoczi */ 37cdd7abfdSStefan Hajnoczi #define IOTHREAD_POLL_MAX_NS_DEFAULT 32768ULL 3890c558beSPeter Xu #else 3990c558beSPeter Xu #define IOTHREAD_POLL_MAX_NS_DEFAULT 0ULL 4090c558beSPeter Xu #endif 41cdd7abfdSStefan Hajnoczi 42be8d8537SStefan Hajnoczi static void *iothread_run(void *opaque) 43be8d8537SStefan Hajnoczi { 44be8d8537SStefan Hajnoczi IOThread *iothread = opaque; 45be8d8537SStefan Hajnoczi 46ab28bd23SPaolo Bonzini rcu_register_thread(); 47b60ec76aSPeter Xu /* 48b60ec76aSPeter Xu * g_main_context_push_thread_default() must be called before anything 49b60ec76aSPeter Xu * in this new thread uses glib. 50b60ec76aSPeter Xu */ 51b60ec76aSPeter Xu g_main_context_push_thread_default(iothread->worker_context); 52*5f50be9bSPaolo Bonzini qemu_set_current_aio_context(iothread->ctx); 5388eb7c29SStefan Hajnoczi iothread->thread_id = qemu_get_thread_id(); 5421c4d15bSPeter Xu qemu_sem_post(&iothread->init_done_sem); 5588eb7c29SStefan Hajnoczi 562362a28eSStefan Hajnoczi while (iothread->running) { 576ca20620SPeter Xu /* 586ca20620SPeter Xu * Note: from functional-wise the g_main_loop_run() below can 596ca20620SPeter Xu * already cover the aio_poll() events, but we can't run the 606ca20620SPeter Xu * main loop unconditionally because explicit aio_poll() here 616ca20620SPeter Xu * is faster than g_main_loop_run() when we do not need the 626ca20620SPeter Xu * gcontext at all (e.g., pure block layer iothreads). In 636ca20620SPeter Xu * other words, when we want to run the gcontext with the 646ca20620SPeter Xu * iothread we need to pay some performance for functionality. 656ca20620SPeter Xu */ 6665c1b5b6SPaolo Bonzini aio_poll(iothread->ctx, true); 67329163cbSWang Yong 686c95363dSPeter Xu /* 696c95363dSPeter Xu * We must check the running state again in case it was 706c95363dSPeter Xu * changed in previous aio_poll() 716c95363dSPeter Xu */ 72d73415a3SStefan Hajnoczi if (iothread->running && qatomic_read(&iothread->run_gcontext)) { 73329163cbSWang Yong g_main_loop_run(iothread->main_loop); 74329163cbSWang Yong } 75be8d8537SStefan Hajnoczi } 76ab28bd23SPaolo Bonzini 77b60ec76aSPeter Xu g_main_context_pop_thread_default(iothread->worker_context); 78ab28bd23SPaolo Bonzini rcu_unregister_thread(); 79be8d8537SStefan Hajnoczi return NULL; 80be8d8537SStefan Hajnoczi } 81be8d8537SStefan Hajnoczi 822362a28eSStefan Hajnoczi /* Runs in iothread_run() thread */ 832362a28eSStefan Hajnoczi static void iothread_stop_bh(void *opaque) 842362a28eSStefan Hajnoczi { 852362a28eSStefan Hajnoczi IOThread *iothread = opaque; 862362a28eSStefan Hajnoczi 872362a28eSStefan Hajnoczi iothread->running = false; /* stop iothread_run() */ 882362a28eSStefan Hajnoczi 892362a28eSStefan Hajnoczi if (iothread->main_loop) { 902362a28eSStefan Hajnoczi g_main_loop_quit(iothread->main_loop); 912362a28eSStefan Hajnoczi } 922362a28eSStefan Hajnoczi } 932362a28eSStefan Hajnoczi 9482d90705SPeter Xu void iothread_stop(IOThread *iothread) 95be8d8537SStefan Hajnoczi { 9682d90705SPeter Xu if (!iothread->ctx || iothread->stopping) { 9782d90705SPeter Xu return; 982f78e491SChrysostomos Nanakos } 99be8d8537SStefan Hajnoczi iothread->stopping = true; 1002362a28eSStefan Hajnoczi aio_bh_schedule_oneshot(iothread->ctx, iothread_stop_bh, iothread); 101be8d8537SStefan Hajnoczi qemu_thread_join(&iothread->thread); 10282d90705SPeter Xu } 10382d90705SPeter Xu 104cdd7abfdSStefan Hajnoczi static void iothread_instance_init(Object *obj) 105cdd7abfdSStefan Hajnoczi { 106cdd7abfdSStefan Hajnoczi IOThread *iothread = IOTHREAD(obj); 107cdd7abfdSStefan Hajnoczi 108cdd7abfdSStefan Hajnoczi iothread->poll_max_ns = IOTHREAD_POLL_MAX_NS_DEFAULT; 10914a2d118SMarc-André Lureau iothread->thread_id = -1; 11021c4d15bSPeter Xu qemu_sem_init(&iothread->init_done_sem, 0); 111b506e0f1SPeter Xu /* By default, we don't run gcontext */ 112d73415a3SStefan Hajnoczi qatomic_set(&iothread->run_gcontext, 0); 113cdd7abfdSStefan Hajnoczi } 114cdd7abfdSStefan Hajnoczi 115dce8921bSFam Zheng static void iothread_instance_finalize(Object *obj) 116dce8921bSFam Zheng { 117dce8921bSFam Zheng IOThread *iothread = IOTHREAD(obj); 118dce8921bSFam Zheng 11982d90705SPeter Xu iothread_stop(iothread); 12014a2d118SMarc-André Lureau 12115544349SPeter Xu /* 12215544349SPeter Xu * Before glib2 2.33.10, there is a glib2 bug that GSource context 12315544349SPeter Xu * pointer may not be cleared even if the context has already been 12415544349SPeter Xu * destroyed (while it should). Here let's free the AIO context 12515544349SPeter Xu * earlier to bypass that glib bug. 12615544349SPeter Xu * 12715544349SPeter Xu * We can remove this comment after the minimum supported glib2 12815544349SPeter Xu * version boosts to 2.33.10. Before that, let's free the 12915544349SPeter Xu * GSources first before destroying any GMainContext. 13015544349SPeter Xu */ 13115544349SPeter Xu if (iothread->ctx) { 13215544349SPeter Xu aio_context_unref(iothread->ctx); 13315544349SPeter Xu iothread->ctx = NULL; 13415544349SPeter Xu } 1355b3ac23fSPeter Xu if (iothread->worker_context) { 1365b3ac23fSPeter Xu g_main_context_unref(iothread->worker_context); 1375b3ac23fSPeter Xu iothread->worker_context = NULL; 1380bd2d233SPeter Xu g_main_loop_unref(iothread->main_loop); 1390bd2d233SPeter Xu iothread->main_loop = NULL; 1405b3ac23fSPeter Xu } 14121c4d15bSPeter Xu qemu_sem_destroy(&iothread->init_done_sem); 142be8d8537SStefan Hajnoczi } 143be8d8537SStefan Hajnoczi 144b506e0f1SPeter Xu static void iothread_init_gcontext(IOThread *iothread) 145b506e0f1SPeter Xu { 146b506e0f1SPeter Xu GSource *source; 147b506e0f1SPeter Xu 148b506e0f1SPeter Xu iothread->worker_context = g_main_context_new(); 149b506e0f1SPeter Xu source = aio_get_g_source(iothread_get_aio_context(iothread)); 150b506e0f1SPeter Xu g_source_attach(source, iothread->worker_context); 151b506e0f1SPeter Xu g_source_unref(source); 1520bd2d233SPeter Xu iothread->main_loop = g_main_loop_new(iothread->worker_context, TRUE); 153b506e0f1SPeter Xu } 154b506e0f1SPeter Xu 155be8d8537SStefan Hajnoczi static void iothread_complete(UserCreatable *obj, Error **errp) 156be8d8537SStefan Hajnoczi { 1572f78e491SChrysostomos Nanakos Error *local_error = NULL; 158be8d8537SStefan Hajnoczi IOThread *iothread = IOTHREAD(obj); 1597a309cc9SMarkus Armbruster char *thread_name; 160be8d8537SStefan Hajnoczi 161be8d8537SStefan Hajnoczi iothread->stopping = false; 1622362a28eSStefan Hajnoczi iothread->running = true; 163668f62ecSMarkus Armbruster iothread->ctx = aio_context_new(errp); 1642f78e491SChrysostomos Nanakos if (!iothread->ctx) { 1652f78e491SChrysostomos Nanakos return; 1662f78e491SChrysostomos Nanakos } 16788eb7c29SStefan Hajnoczi 168b506e0f1SPeter Xu /* 169b506e0f1SPeter Xu * Init one GMainContext for the iothread unconditionally, even if 170b506e0f1SPeter Xu * it's not used 171b506e0f1SPeter Xu */ 172b506e0f1SPeter Xu iothread_init_gcontext(iothread); 173b506e0f1SPeter Xu 1745e5db499SStefan Hajnoczi aio_context_set_poll_params(iothread->ctx, 1755e5db499SStefan Hajnoczi iothread->poll_max_ns, 1765e5db499SStefan Hajnoczi iothread->poll_grow, 1775e5db499SStefan Hajnoczi iothread->poll_shrink, 1780d9d86fbSStefan Hajnoczi &local_error); 1790d9d86fbSStefan Hajnoczi if (local_error) { 1800d9d86fbSStefan Hajnoczi error_propagate(errp, local_error); 1810d9d86fbSStefan Hajnoczi aio_context_unref(iothread->ctx); 1820d9d86fbSStefan Hajnoczi iothread->ctx = NULL; 1830d9d86fbSStefan Hajnoczi return; 1840d9d86fbSStefan Hajnoczi } 1850d9d86fbSStefan Hajnoczi 186be8d8537SStefan Hajnoczi /* This assumes we are called from a thread with useful CPU affinity for us 187be8d8537SStefan Hajnoczi * to inherit. 188be8d8537SStefan Hajnoczi */ 1897a309cc9SMarkus Armbruster thread_name = g_strdup_printf("IO %s", 1907a309cc9SMarkus Armbruster object_get_canonical_path_component(OBJECT(obj))); 191d21e8776SPaolo Bonzini qemu_thread_create(&iothread->thread, thread_name, iothread_run, 192be8d8537SStefan Hajnoczi iothread, QEMU_THREAD_JOINABLE); 193d21e8776SPaolo Bonzini g_free(thread_name); 19488eb7c29SStefan Hajnoczi 19588eb7c29SStefan Hajnoczi /* Wait for initialization to complete */ 19688eb7c29SStefan Hajnoczi while (iothread->thread_id == -1) { 19721c4d15bSPeter Xu qemu_sem_wait(&iothread->init_done_sem); 19888eb7c29SStefan Hajnoczi } 199be8d8537SStefan Hajnoczi } 200be8d8537SStefan Hajnoczi 2015e5db499SStefan Hajnoczi typedef struct { 2025e5db499SStefan Hajnoczi const char *name; 2035e5db499SStefan Hajnoczi ptrdiff_t offset; /* field's byte offset in IOThread struct */ 2045e5db499SStefan Hajnoczi } PollParamInfo; 2055e5db499SStefan Hajnoczi 2065e5db499SStefan Hajnoczi static PollParamInfo poll_max_ns_info = { 2075e5db499SStefan Hajnoczi "poll-max-ns", offsetof(IOThread, poll_max_ns), 2085e5db499SStefan Hajnoczi }; 2095e5db499SStefan Hajnoczi static PollParamInfo poll_grow_info = { 2105e5db499SStefan Hajnoczi "poll-grow", offsetof(IOThread, poll_grow), 2115e5db499SStefan Hajnoczi }; 2125e5db499SStefan Hajnoczi static PollParamInfo poll_shrink_info = { 2135e5db499SStefan Hajnoczi "poll-shrink", offsetof(IOThread, poll_shrink), 2145e5db499SStefan Hajnoczi }; 2155e5db499SStefan Hajnoczi 2165e5db499SStefan Hajnoczi static void iothread_get_poll_param(Object *obj, Visitor *v, 2170d9d86fbSStefan Hajnoczi const char *name, void *opaque, Error **errp) 2180d9d86fbSStefan Hajnoczi { 2190d9d86fbSStefan Hajnoczi IOThread *iothread = IOTHREAD(obj); 2205e5db499SStefan Hajnoczi PollParamInfo *info = opaque; 2215e5db499SStefan Hajnoczi int64_t *field = (void *)iothread + info->offset; 2220d9d86fbSStefan Hajnoczi 2235e5db499SStefan Hajnoczi visit_type_int64(v, name, field, errp); 2240d9d86fbSStefan Hajnoczi } 2250d9d86fbSStefan Hajnoczi 2265e5db499SStefan Hajnoczi static void iothread_set_poll_param(Object *obj, Visitor *v, 2270d9d86fbSStefan Hajnoczi const char *name, void *opaque, Error **errp) 2280d9d86fbSStefan Hajnoczi { 2290d9d86fbSStefan Hajnoczi IOThread *iothread = IOTHREAD(obj); 2305e5db499SStefan Hajnoczi PollParamInfo *info = opaque; 2315e5db499SStefan Hajnoczi int64_t *field = (void *)iothread + info->offset; 2320d9d86fbSStefan Hajnoczi int64_t value; 2330d9d86fbSStefan Hajnoczi 234668f62ecSMarkus Armbruster if (!visit_type_int64(v, name, &value, errp)) { 235dcfe4805SMarkus Armbruster return; 2360d9d86fbSStefan Hajnoczi } 2370d9d86fbSStefan Hajnoczi 2380d9d86fbSStefan Hajnoczi if (value < 0) { 239dcfe4805SMarkus Armbruster error_setg(errp, "%s value must be in range [0, %" PRId64 "]", 2405e5db499SStefan Hajnoczi info->name, INT64_MAX); 241dcfe4805SMarkus Armbruster return; 2420d9d86fbSStefan Hajnoczi } 2430d9d86fbSStefan Hajnoczi 2445e5db499SStefan Hajnoczi *field = value; 2450d9d86fbSStefan Hajnoczi 2460d9d86fbSStefan Hajnoczi if (iothread->ctx) { 2475e5db499SStefan Hajnoczi aio_context_set_poll_params(iothread->ctx, 2485e5db499SStefan Hajnoczi iothread->poll_max_ns, 2495e5db499SStefan Hajnoczi iothread->poll_grow, 2505e5db499SStefan Hajnoczi iothread->poll_shrink, 251dcfe4805SMarkus Armbruster errp); 2520d9d86fbSStefan Hajnoczi } 2530d9d86fbSStefan Hajnoczi } 2540d9d86fbSStefan Hajnoczi 255be8d8537SStefan Hajnoczi static void iothread_class_init(ObjectClass *klass, void *class_data) 256be8d8537SStefan Hajnoczi { 257be8d8537SStefan Hajnoczi UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass); 258be8d8537SStefan Hajnoczi ucc->complete = iothread_complete; 2590d9d86fbSStefan Hajnoczi 2600d9d86fbSStefan Hajnoczi object_class_property_add(klass, "poll-max-ns", "int", 2615e5db499SStefan Hajnoczi iothread_get_poll_param, 2625e5db499SStefan Hajnoczi iothread_set_poll_param, 263d2623129SMarkus Armbruster NULL, &poll_max_ns_info); 2645e5db499SStefan Hajnoczi object_class_property_add(klass, "poll-grow", "int", 2655e5db499SStefan Hajnoczi iothread_get_poll_param, 2665e5db499SStefan Hajnoczi iothread_set_poll_param, 267d2623129SMarkus Armbruster NULL, &poll_grow_info); 2685e5db499SStefan Hajnoczi object_class_property_add(klass, "poll-shrink", "int", 2695e5db499SStefan Hajnoczi iothread_get_poll_param, 2705e5db499SStefan Hajnoczi iothread_set_poll_param, 271d2623129SMarkus Armbruster NULL, &poll_shrink_info); 272be8d8537SStefan Hajnoczi } 273be8d8537SStefan Hajnoczi 274be8d8537SStefan Hajnoczi static const TypeInfo iothread_info = { 275be8d8537SStefan Hajnoczi .name = TYPE_IOTHREAD, 276be8d8537SStefan Hajnoczi .parent = TYPE_OBJECT, 277be8d8537SStefan Hajnoczi .class_init = iothread_class_init, 278be8d8537SStefan Hajnoczi .instance_size = sizeof(IOThread), 279cdd7abfdSStefan Hajnoczi .instance_init = iothread_instance_init, 280be8d8537SStefan Hajnoczi .instance_finalize = iothread_instance_finalize, 281be8d8537SStefan Hajnoczi .interfaces = (InterfaceInfo[]) { 282be8d8537SStefan Hajnoczi {TYPE_USER_CREATABLE}, 283be8d8537SStefan Hajnoczi {} 284be8d8537SStefan Hajnoczi }, 285be8d8537SStefan Hajnoczi }; 286be8d8537SStefan Hajnoczi 287be8d8537SStefan Hajnoczi static void iothread_register_types(void) 288be8d8537SStefan Hajnoczi { 289be8d8537SStefan Hajnoczi type_register_static(&iothread_info); 290be8d8537SStefan Hajnoczi } 291be8d8537SStefan Hajnoczi 292be8d8537SStefan Hajnoczi type_init(iothread_register_types) 293be8d8537SStefan Hajnoczi 294be8d8537SStefan Hajnoczi char *iothread_get_id(IOThread *iothread) 295be8d8537SStefan Hajnoczi { 2967a309cc9SMarkus Armbruster return g_strdup(object_get_canonical_path_component(OBJECT(iothread))); 297be8d8537SStefan Hajnoczi } 298be8d8537SStefan Hajnoczi 299be8d8537SStefan Hajnoczi AioContext *iothread_get_aio_context(IOThread *iothread) 300be8d8537SStefan Hajnoczi { 301be8d8537SStefan Hajnoczi return iothread->ctx; 302be8d8537SStefan Hajnoczi } 303dc3dd0d2SStefan Hajnoczi 304dc3dd0d2SStefan Hajnoczi static int query_one_iothread(Object *object, void *opaque) 305dc3dd0d2SStefan Hajnoczi { 306c3033fd3SEric Blake IOThreadInfoList ***tail = opaque; 307dc3dd0d2SStefan Hajnoczi IOThreadInfo *info; 308dc3dd0d2SStefan Hajnoczi IOThread *iothread; 309dc3dd0d2SStefan Hajnoczi 310dc3dd0d2SStefan Hajnoczi iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD); 311dc3dd0d2SStefan Hajnoczi if (!iothread) { 312dc3dd0d2SStefan Hajnoczi return 0; 313dc3dd0d2SStefan Hajnoczi } 314dc3dd0d2SStefan Hajnoczi 315dc3dd0d2SStefan Hajnoczi info = g_new0(IOThreadInfo, 1); 316dc3dd0d2SStefan Hajnoczi info->id = iothread_get_id(iothread); 317dc3dd0d2SStefan Hajnoczi info->thread_id = iothread->thread_id; 3185fc00480SPavel Hrdina info->poll_max_ns = iothread->poll_max_ns; 3195fc00480SPavel Hrdina info->poll_grow = iothread->poll_grow; 3205fc00480SPavel Hrdina info->poll_shrink = iothread->poll_shrink; 321dc3dd0d2SStefan Hajnoczi 322c3033fd3SEric Blake QAPI_LIST_APPEND(*tail, info); 323dc3dd0d2SStefan Hajnoczi return 0; 324dc3dd0d2SStefan Hajnoczi } 325dc3dd0d2SStefan Hajnoczi 326dc3dd0d2SStefan Hajnoczi IOThreadInfoList *qmp_query_iothreads(Error **errp) 327dc3dd0d2SStefan Hajnoczi { 328dc3dd0d2SStefan Hajnoczi IOThreadInfoList *head = NULL; 329dc3dd0d2SStefan Hajnoczi IOThreadInfoList **prev = &head; 330bc2256c4SDaniel P. Berrange Object *container = object_get_objects_root(); 331dc3dd0d2SStefan Hajnoczi 332dc3dd0d2SStefan Hajnoczi object_child_foreach(container, query_one_iothread, &prev); 333dc3dd0d2SStefan Hajnoczi return head; 334dc3dd0d2SStefan Hajnoczi } 335dce8921bSFam Zheng 336329163cbSWang Yong GMainContext *iothread_get_g_main_context(IOThread *iothread) 337329163cbSWang Yong { 338d73415a3SStefan Hajnoczi qatomic_set(&iothread->run_gcontext, 1); 339b506e0f1SPeter Xu aio_notify(iothread->ctx); 340329163cbSWang Yong return iothread->worker_context; 341329163cbSWang Yong } 3420173e21bSPeter Xu 3430173e21bSPeter Xu IOThread *iothread_create(const char *id, Error **errp) 3440173e21bSPeter Xu { 3450173e21bSPeter Xu Object *obj; 3460173e21bSPeter Xu 3470173e21bSPeter Xu obj = object_new_with_props(TYPE_IOTHREAD, 3480173e21bSPeter Xu object_get_internal_root(), 3490173e21bSPeter Xu id, errp, NULL); 3500173e21bSPeter Xu 3510173e21bSPeter Xu return IOTHREAD(obj); 3520173e21bSPeter Xu } 3530173e21bSPeter Xu 3540173e21bSPeter Xu void iothread_destroy(IOThread *iothread) 3550173e21bSPeter Xu { 3560173e21bSPeter Xu object_unparent(OBJECT(iothread)); 3570173e21bSPeter Xu } 358fbcc6923SStefan Hajnoczi 359fbcc6923SStefan Hajnoczi /* Lookup IOThread by its id. Only finds user-created objects, not internal 360fbcc6923SStefan Hajnoczi * iothread_create() objects. */ 361fbcc6923SStefan Hajnoczi IOThread *iothread_by_id(const char *id) 362fbcc6923SStefan Hajnoczi { 363fbcc6923SStefan Hajnoczi return IOTHREAD(object_resolve_path_type(id, TYPE_IOTHREAD, NULL)); 364fbcc6923SStefan Hajnoczi } 365ad22c308SElena Ufimtseva 366ad22c308SElena Ufimtseva bool qemu_in_iothread(void) 367ad22c308SElena Ufimtseva { 368ad22c308SElena Ufimtseva return qemu_get_current_aio_context() == qemu_get_aio_context() ? 369ad22c308SElena Ufimtseva false : true; 370ad22c308SElena Ufimtseva } 371