That's because the virtual vm clock is enabled at initialization. It doesn't need to wait for invoking vm_start() to fire. 发件人：Dr. David Alan Gilbert 收件人：龚磊, 抄送：Paolo Bonzini,Jan Kiszka,Amit Shah,Juan Quintela,黄伟栋,qemu-devel@nongnu.org,k...@vger.kernel.org, 时间：2016-08-08 22:18:15 主题:Re: [Qemu-devel] [Question] virtio-serial misses irq delivery on migration?
* Gonglei (Arei) (arei.gong...@huawei.com) wrote: > Hi Dave, > > > > -----Original Message----- > > From: Dr. David Alan Gilbert [mailto:dgilb...@redhat.com] > > Sent: Monday, August 08, 2016 8:13 PM > > To: Gonglei (Arei) > > Cc: Paolo Bonzini; jan.kis...@siemens.com; amit.s...@redhat.com; > > quint...@redhat.com; Huangweidong (C); qemu-devel@nongnu.org; > > k...@vger.kernel.org > > Subject: Re: [Qemu-devel] [Question] virtio-serial misses irq delivery on > > migration? > > > > * Gonglei (Arei) (arei.gong...@huawei.com) wrote: > > > Hi all, > > > > > > I might catch the bug. Now, we rely on a vm_clock timer to assure that the > > vcpus are started > > > before we invoke send_control_event(),which queue a message in the virtio > > ring and trigger a irq. > > > > > > In actually, we can't attach our initial intention under a special > > > situation: > > > > > > 1. the process of migration destination is in a coroutine > > > Commit 82a4da79fd6 > > > 2. The corountine will yiled the cpu (calling > > > yield_until_fd_readable(s->fd)) > > > if the Qemu encounter a EAGIN while reading QEMUFile. > > > commit 595ab64169b > > > > > > static ssize_t socket_get_buffer(void *opaque, uint8_t *buf, int64_t pos, > > > size_t size) > > > { > > > QEMUFileSocket *s = opaque; > > > ssize_t len; > > > > > > for (;;) { > > > len = qemu_recv(s->fd, buf, size, 0); > > > if (len != -1) { > > > break; > > > } > > > if (socket_error() == EAGAIN) { > > > yield_until_fd_readable(s->fd); > > > } else if (socket_error() != EINTR) { > > > break; > > > } > > > } > > > > > > if (len == -1) { > > > len = -socket_error(); > > > } > > > return len; > > > } > > > > > > 3. The main thread can get the cpu and timer will run, asumes that we get > > EAGIN > > > after invoking fetch_active_ports_list(). > > > > I don't understand the details of this interrupt injection, or why the timer > > will run if we're still not finished migration; it doesn't sound right that > > a > > QEMU_CLOCK_VIRTUAL > > timer should trigger while we're still receiving the VM and the guest is > > paused. > > > > Because the migration coroutine will yiled cpu if it get a EAGAIN error from > unix socket. > You can see the above step 2) > > For the upstream qemu, you can see the hander of QIO_CHANNEL_ERR_BLOCK in > channel_get_buffer() > > static ssize_t channel_get_buffer(void *opaque, > uint8_t *buf, > int64_t pos, > size_t size) > { > QIOChannel *ioc = QIO_CHANNEL(opaque); > ssize_t ret; > > do { > ret = qio_channel_read(ioc, (char *)buf, size, NULL); > if (ret < 0) { > if (ret == QIO_CHANNEL_ERR_BLOCK) { > qio_channel_yield(ioc, G_IO_IN); // yiled cpu > } else { > /* XXX handle Error * object */ > return -EIO; > } > } > } while (ret == QIO_CHANNEL_ERR_BLOCK); > > return ret; > } Yes, I understand it yields; but I would have expected the timer code not to fire virtual timers while the VM is in paused state. > > However, would it be fixed by using a vm_change_state_handler like > > ui/spice-core.c does? > > > > I'll check this method, thanks! > Dave > Regards, > -Gonglei > > > Dave > > > > > > > 4. reproduce the problem by fault injection. > > > > > > The debug logs: > > > > > > [2016-08-06 16:52:56] handle_qmp_command:5106 qmp_cmd_name: > > query-migrate-capabilities > > > [2016-08-06 16:52:56] handle_qmp_command:5116 qmp_cmd_name: > > migrate-set-capabilities, qmp_cmd_arguments: {"capabilities": [{"state": > > false, > > "capability": "xbzrle"}]} > > > [2016-08-06 16:52:56] handle_qmp_command:5106 qmp_cmd_name: > > query-migrate-capabilities > > > [2016-08-06 16:52:56] handle_qmp_command:5116 qmp_cmd_name: > > migrate-set-capabilities, qmp_cmd_arguments: {"capabilities": [{"state": > > false, > > "capability": "rdma-pin-all"}]} > > > [2016-08-06 16:52:56] process_incoming_migration_co:170 gonglei: enter > > process_incoming_migration_co() // Enter corountine > > > [2016-08-06 16:53:01] apic_dispatch_post_load:370 gonglei: > > apic_dispatch_post_load > > > [2016-08-06 16:53:01] apic_dispatch_post_load:370 gonglei: > > apic_dispatch_post_load > > > [2016-08-06 16:53:01] apic_dispatch_post_load:370 gonglei: > > apic_dispatch_post_load > > > [2016-08-06 16:53:01] apic_dispatch_post_load:370 gonglei: > > apic_dispatch_post_load > > > [2016-08-06 16:53:01] apic_dispatch_post_load:370 gonglei: > > apic_dispatch_post_load > > > [2016-08-06 16:53:01] apic_dispatch_post_load:370 gonglei: > > apic_dispatch_post_load > > > [2016-08-06 16:53:01] apic_dispatch_post_load:370 gonglei: > > apic_dispatch_post_load > > > [2016-08-06 16:53:01] apic_dispatch_post_load:370 gonglei: > > apic_dispatch_post_load > > > [2016-08-06 16:53:01] kvm_ioapic_put:97 gonglei: kvm_ioapic_put > > > [2016-08-06 16:53:01] virtio_serial_load:745 gonglei: virtio_serial_load > > > will > > init virtqueue > > > [2016-08-06 16:53:01] fetch_active_ports_list:735 gonglei: ************** > > begin to inject debug ********** // fault injection begin, migration > > coroutine yiled cpu > > > [2016-08-06 16:53:01] timerlist_run_timers:496 gonglei: expire_time: 1, > > current_time: 9750771061592 //vm_clock timer boom > > > [2016-08-06 16:53:01] virtio_serial_post_load_timer_cb:658 gonglei: > > virtio_serial_post_load_timer_cb //calling the timer callback > > > [2016-08-06 16:53:01] send_control_event:225 virtio serial port 1 send > > control message event = 6, value = 0 // send a message to the guest, raise > > the > > irq line. > > > [2016-08-06 16:53:01] virtio_serial_post_load_timer_cb:669 gonglei: > > port->host_connected: 0 > > > [2016-08-06 16:53:01] monitor_qapi_event_emit:483 {"timestamp": > > {"seconds": 1470473581, "microseconds": 64056}, "event": > > "VSERPORT_CHANGE", "data": {"open": true, "id": "channel0"}} > > > [2016-08-06 16:53:01] send_control_event:225 virtio serial port 3 send > > control message event = 6, value = 0 > > > [2016-08-06 16:53:01] virtio_serial_post_load_timer_cb:669 gonglei: > > port->host_connected: 0 > > > [2016-08-06 16:53:01] timerlist_run_timers:496 gonglei: expire_time: > > 9750770788478, current_time: 9750771061592 > > > [2016-08-06 16:53:01] kvm_put_apic_state:32 gonglei: kvm_put_apic_state > > //Enter migration coroutine again, and the restore the lapic register, the > > previous lapic's info will be covered :( > > > [2016-08-06 16:53:01] kvm_put_apic_state:32 gonglei: kvm_put_apic_state > > > [2016-08-06 16:53:01] kvm_put_apic_state:32 gonglei: kvm_put_apic_state > > > [2016-08-06 16:53:01] kvm_put_apic_state:32 gonglei: kvm_put_apic_state > > > [2016-08-06 16:53:01] kvm_put_apic_state:32 gonglei: kvm_put_apic_state > > > [2016-08-06 16:53:01] kvm_put_apic_state:32 gonglei: kvm_put_apic_state > > > [2016-08-06 16:53:01] kvm_put_apic_state:32 gonglei: kvm_put_apic_state > > > [2016-08-06 16:53:01] kvm_put_apic_state:32 gonglei: kvm_put_apic_state > > > [2016-08-06 16:53:01] handle_qmp_command:5106 qmp_cmd_name: cont > > > [2016-08-06 16:53:01] qmp_cont:189 qmp cont is received and vm is started > > > [2016-08-06 16:53:01] vm_start:981 gonglei: enter vm_start > > //enter vm_start here > > > [2016-08-06 16:53:01] virtio_set_status:522 virtio-net device status is 7 > > > that > > means DRIVER OK > > > [2016-08-06 16:53:01] virtio_set_status:522 virtio-serial device status > > > is 7 > > that means DRIVER OK > > > [2016-08-06 16:53:01] virtio_set_status:522 virtio-scsi device status is > > > 7 that > > means DRIVER OK > > > [2016-08-06 16:53:01] vm_start:1000 vm_state-notify:23ms > > > [2016-08-06 16:53:01] qemu_clock_enable:163 gonglei: type: 1, enabled: 1, > > old: 1 > > > [2016-08-06 16:53:01] monitor_qapi_event_emit:483 {"timestamp": > > {"seconds": 1470473581, "microseconds": 112191}, "event": "RESUME"} > > > [2016-08-06 16:53:01] timerlist_run_timers:496 gonglei: expire_time: > > 9750772061592, current_time: 9750794269805 > > > [2016-08-06 16:53:01] send_control_event:225 virtio serial port 1 send > > control message event = 6, value = 1 > > > [2016-08-06 16:53:01] timerlist_run_timers:496 gonglei: expire_time: > > 9750795284148, current_time: 9750795312685 > > > [2016-08-06 16:53:01] send_control_event:225 virtio serial port 3 send > > control message event = 6, value = 1 > > > [2016-08-06 16:53:01] timerlist_run_timers:496 gonglei: expire_time: > > 9750796329656, current_time: 9750796369458 > > > [2016-08-06 16:53:01] timerlist_run_timers:496 gonglei: expire_time: > > 9750797396208, current_time: 9750797426752 > > > [2016-08-06 16:53:01] timerlist_run_timers:496 gonglei: expire_time: > > 9750798445707, current_time: 9750798477520 > > > [2016-08-06 16:53:01] timerlist_run_timers:496 gonglei: expire_time: > > 9750799496162, current_time: 9750799532183 > > > [2016-08-06 16:53:01] timerlist_run_timers:496 gonglei: expire_time: > > 9750800556817, current_time: 9750800588741 > > > [2016-08-06 16:53:01] timerlist_run_timers:496 gonglei: expire_time: > > 9750801606596, current_time: 9750801637961 > > > > > > > > > The below is my debugging diff (Not based on the newest master branch) > > > > > > diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c > > > index 6a45af9..a00b02f 100644 > > > --- a/hw/char/virtio-serial-bus.c > > > +++ b/hw/char/virtio-serial-bus.c > > > @@ -654,6 +654,7 @@ static void virtio_serial_post_load_timer_cb(void > > *opaque) > > > if (!s->post_load) { > > > return; > > > } > > > + QEMU_LOG("gonglei: virtio_serial_post_load_timer_cb\n"); > > > for (i = 0 ; i < s->post_load->nr_active_ports; ++i) { > > > port = s->post_load->connected[i].port; > > > host_connected = s->post_load->connected[i].host_connected; > > > @@ -664,6 +665,7 @@ static void virtio_serial_post_load_timer_cb(void > > *opaque) > > > */ > > > send_control_event(s, port->id, > > VIRTIO_CONSOLE_PORT_OPEN, > > > port->host_connected); > > > + QEMU_LOG("gonglei: port->host_connected: %u\n", > > port->host_connected); > > > } > > > vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port); > > > if (vsc->set_guest_connected) { > > > @@ -729,6 +731,8 @@ static int fetch_active_ports_list(QEMUFile *f, int > > version_id, > > > } > > > } > > > timer_mod(s->post_load->timer, 1); > > > + QEMU_LOG("gonglei: ************** begin to inject debug > > **********\n"); > > > + yield_until_fd_readable(qemu_get_fd(f)); > > > return 0; > > > } > > > > > > @@ -737,7 +741,7 @@ static int virtio_serial_load(QEMUFile *f, void > > *opaque, int version_id) > > > if (version_id > 3) { > > > return -EINVAL; > > > } > > > - > > > + QEMU_LOG("gonglei: virtio_serial_load will init virtqueue\n"); > > > /* The virtio device */ > > > return virtio_load(VIRTIO_DEVICE(opaque), f, version_id); > > > } > > > diff --git a/hw/i386/kvm/apic.c b/hw/i386/kvm/apic.c > > > index 5b47056..2d988cb 100644 > > > --- a/hw/i386/kvm/apic.c > > > +++ b/hw/i386/kvm/apic.c > > > @@ -29,7 +29,7 @@ void kvm_put_apic_state(DeviceState *dev, struct > > kvm_lapic_state *kapic) > > > { > > > APICCommonState *s = APIC_COMMON(dev); > > > int i; > > > - > > > + QEMU_LOG("gonglei: kvm_put_apic_state\n"); > > > memset(kapic, 0, sizeof(*kapic)); > > > kvm_apic_set_reg(kapic, 0x2, s->id << 24); > > > kvm_apic_set_reg(kapic, 0x8, s->tpr); > > > diff --git a/hw/i386/kvm/ioapic.c b/hw/i386/kvm/ioapic.c > > > index d2a6c4c..07699ec 100644 > > > --- a/hw/i386/kvm/ioapic.c > > > +++ b/hw/i386/kvm/ioapic.c > > > @@ -94,7 +94,7 @@ static void kvm_ioapic_put(IOAPICCommonState *s) > > > > > > chip.chip_id = KVM_IRQCHIP_IOAPIC; > > > kioapic = &chip.chip.ioapic; > > > - > > > + QEMU_LOG("gonglei: kvm_ioapic_put\n"); > > > kioapic->id = s->id; > > > kioapic->ioregsel = s->ioregsel; > > > kioapic->base_address = s->busdev.mmio[0].addr; > > > diff --git a/hw/intc/apic_common.c b/hw/intc/apic_common.c > > > index 042e960..110be20 100644 > > > --- a/hw/intc/apic_common.c > > > +++ b/hw/intc/apic_common.c > > > @@ -366,6 +366,7 @@ static int apic_dispatch_post_load(void *opaque, int > > version_id) > > > if (info->post_load) { > > > info->post_load(s); > > > } > > > + QEMU_LOG("gonglei: apic_dispatch_post_load\n"); > > > return 0; > > > } > > > > > > diff --git a/migration/migration.c b/migration/migration.c > > > index 92c1427..d074c0a 100644 > > > --- a/migration/migration.c > > > +++ b/migration/migration.c > > > @@ -167,7 +167,7 @@ static void process_incoming_migration_co(void > > *opaque) > > > const char *arpGuestCMD = > > "{\"execute\":\"guest-write-flag-arp\"}\n"; > > > const char *portName = "charchannel1"; > > > size_t uRet; > > > - > > > + QEMU_LOG("gonglei: enter process_incoming_migration_co()\n"); > > > ret = qemu_loadvm_state(f); > > > qemu_fclose(f); > > > free_xbzrle_decoded_buf(); > > > diff --git a/qemu-timer.c b/qemu-timer.c > > > index 5741f0d..dd36bc9 100644 > > > --- a/qemu-timer.c > > > +++ b/qemu-timer.c > > > @@ -160,6 +160,7 @@ void qemu_clock_enable(QEMUClockType type, bool > > enabled) > > > QEMUTimerList *tl; > > > bool old = clock->enabled; > > > clock->enabled = enabled; > > > + QEMU_LOG("gonglei: type: %u, enabled: %u, old: %u\n", type, enabled, > > old); > > > if (enabled && !old) { > > > qemu_clock_notify(type); > > > } else if (!enabled && old) { > > > @@ -475,6 +476,7 @@ bool timerlist_run_timers(QEMUTimerList > > *timer_list) > > > bool progress = false; > > > QEMUTimerCB *cb; > > > void *opaque; > > > + static int count = 10; > > > > > > qemu_event_reset(&timer_list->timers_done_ev); > > > if (!timer_list->clock->enabled) { > > > @@ -489,7 +491,10 @@ bool timerlist_run_timers(QEMUTimerList > > *timer_list) > > > qemu_mutex_unlock(&timer_list->active_timers_lock); > > > break; > > > } > > > - > > > + if (timer_list->clock->type == QEMU_CLOCK_VIRTUAL && count-- > 0) { > > > + QEMU_LOG("gonglei: expire_time: %lld, current_time: %lld\n", > > > + ts->expire_time, current_time); > > > + } > > > /* remove timer from the list before calling the callback */ > > > timer_list->active_timers = ts->next; > > > ts->next = NULL; > > > diff --git a/vl.c b/vl.c > > > index 06f34fe..824b246 100644 > > > --- a/vl.c > > > +++ b/vl.c > > > @@ -978,7 +978,7 @@ void vm_start(void) > > > { > > > RunState requested; > > > int64_t start_time, end_time; > > > - > > > + QEMU_LOG("gonglei: enter vm_start\n"); > > > qemu_vmstop_requested(&requested); > > > if (runstate_is_running() && requested == RUN_STATE_MAX) { > > > return; > > > > > > > > > Can we wait looply the migration process finished when EAGAIN? > > > > > > Regards, > > > -Gonglei > > > > > > > > > > -----Original Message----- > > > > From: Gonglei (Arei) > > > > Sent: Friday, August 05, 2016 5:14 PM > > > > To: Paolo Bonzini; 'jan.kis...@siemens.com'; 'amit.s...@redhat.com' > > > > Cc: qemu-devel@nongnu.org; k...@vger.kernel.org; Huangweidong (C) > > > > Subject: [Question] virtio-serial misses irq delivery on migration? > > > > > > > > Hi Paolo , Jan, Amit > > > > > > > > Recently we encountered a problem that the virtio-serial can't work > > > > after > > > > Migration in RH5.5 VM. The bigger problem is, I can't reproduce it. :( > > > > > > > > It's phenomenon was much like BZ 867366, the usb-table mouse didn't work > > > > because > > > > the uhci and virtio-serial shard the irq line (using IOAPIC, not MSI). > > > > The new > > > > interrupt > > > > can't be injected to VM because the irq line bit had been set to 1, but > > > > the > > > > frontend > > > > driver never handle it or never know it. > > > > > > > > Bug 867366 - virtio-serial misses irq delivery on migration > > > > https://bugzilla.redhat.com/show_bug.cgi?id=867366 > > > > > > > > But my qemu is the newest qemu, Both commit > > 80dcfb8532"virtio-serial-bus: > > > > post_load > > > > send_event when vm is running" and commit bc6b815d9e " virtio-serial: > > > > propagate > > > > guest_connected to the port on post_load" are applied. > > > > > > > > I noticed that Paolo posted another problem maybe have a pertential > > problem > > > > about > > > > apic in Comment 23. But this patch > > > > https://bugzilla.redhat.com/attachment.cgi?id=635535&action=diff > > > > haven't merged into qemu master. > > > > > > > > Would you give me some clues please? Thanks! > > > > > > > > Regards, > > > > -Gonglei > > > > > > > > > > > > -- > > Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
