On Tue, Nov 11, 2014 at 09:17:10AM +0800, Ming Lei wrote:
> +static void notify_guest_bh(void *opaque)
> +{
> + VirtIOSCSI *s = opaque;
> + unsigned int qid;
> + uint64_t pending = s->pending_guest_notify;
> +
> + s->pending_guest_notify = 0;
> +
> + while ((qid = ffsl(pending))) {
> + qid--;
> + event_notifier_set(&s->cmd_vrings[qid]->guest_notifier);
> + pending &= ~(1 << qid);
> + }
> +}
Looks like we're not honoring virtio's usual interrupt mitigation
mechanism (e.g. EVENT_IDX) for virtio-scsi. Why is
vring_should_notify() not used?
> +
> static void virtio_scsi_bad_req(void)
> {
> error_report("wrong size for virtio-scsi headers");
> @@ -824,7 +839,12 @@ void virtio_scsi_common_realize(DeviceState *dev, Error
> **errp,
> }
>
> if (s->conf.iothread) {
> - virtio_scsi_set_iothread(VIRTIO_SCSI(s), s->conf.iothread);
> + VirtIOSCSI *vis = VIRTIO_SCSI(s);
> +
> + QEMU_BUILD_BUG_ON(VIRTIO_PCI_QUEUE_MAX > 64);
> + virtio_scsi_set_iothread(vis, s->conf.iothread);
> + vis->pending_guest_notify = 0;
> + vis->guest_notify_bh = aio_bh_new(vis->ctx, notify_guest_bh, vis);
Have you checked state transitions like PCI or virtio reset? They need
to cancel the BH and clear ->pending_guest_notify.
There is also a transition from dataplane to non-dataplane mode for live
migration.
Please make sure no interrupts are dropped or stale data is kept across
these transitions.
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