at 11:18 PM, Stefan Hajnoczi <stefa...@gmail.com> wrote: > I think that is incorrect. QEMU has guest notifier emulation for the > non-KVM (and non-MSI-X PCI) cases. When there is no irqfd support > available, QEMU sets up a regular eventfd and calls > virtio_queue_guest_notifier_read() when it becomes readable.
Thanks Stefan. I finally understand why there is a `with_irqfd` parameter for virtio_queue_set_guest_notifier_fd_handler. But if `with_irqfd` is false, it seems OK to directly call virtio_irq(). Why still bother using an eventfd? Is it for interrupt batching?
