diff options
Diffstat (limited to 'hw/virtio/virtio.c')
-rw-r--r-- | hw/virtio/virtio.c | 36 |
1 files changed, 28 insertions, 8 deletions
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 138a414cbe..1af2de2714 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -1330,13 +1330,6 @@ static void virtio_set_isr(VirtIODevice *vdev, int value) } } -void virtio_irq(VirtQueue *vq) -{ - trace_virtio_irq(vq); - virtio_set_isr(vq->vdev, 0x1); - virtio_notify_vector(vq->vdev, vq->vector); -} - bool virtio_should_notify(VirtIODevice *vdev, VirtQueue *vq) { uint16_t old, new; @@ -1360,6 +1353,33 @@ bool virtio_should_notify(VirtIODevice *vdev, VirtQueue *vq) return !v || vring_need_event(vring_get_used_event(vq), new, old); } +void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq) +{ + if (!virtio_should_notify(vdev, vq)) { + return; + } + + trace_virtio_notify_irqfd(vdev, vq); + + /* + * virtio spec 1.0 says ISR bit 0 should be ignored with MSI, but + * windows drivers included in virtio-win 1.8.0 (circa 2015) are + * incorrectly polling this bit during crashdump and hibernation + * in MSI mode, causing a hang if this bit is never updated. + * Recent releases of Windows do not really shut down, but rather + * log out and hibernate to make the next startup faster. Hence, + * this manifested as a more serious hang during shutdown with + * + * Next driver release from 2016 fixed this problem, so working around it + * is not a must, but it's easy to do so let's do it here. + * + * Note: it's safe to update ISR from any thread as it was switched + * to an atomic operation. + */ + virtio_set_isr(vq->vdev, 0x1); + event_notifier_set(&vq->guest_notifier); +} + void virtio_notify(VirtIODevice *vdev, VirtQueue *vq) { if (!virtio_should_notify(vdev, vq)) { @@ -1994,7 +2014,7 @@ static void virtio_queue_guest_notifier_read(EventNotifier *n) { VirtQueue *vq = container_of(n, VirtQueue, guest_notifier); if (event_notifier_test_and_clear(n)) { - virtio_irq(vq); + virtio_notify_vector(vq->vdev, vq->vector); } } |