Re: vioif(4) vs. VirtualBox?

[Valery Ushakov <uwe%stderr.spb.ru@localhost>]

On Thu, Feb 15, 2018 at 13:45:39 +0300, Valery Ushakov wrote:

> As far as I can tell what happens is that the first control queue
> reply from the host is missed.  VBox writes the new index (1) for its
> reply and triggers an interrupt, but netbsd in virtio_vq_intr() still
> reads the old (0) value for vq->vq_used->idx and so it blocks in
> vioif_ctrl_rx() waiting for sc_ctrl_wait.
> 
> This used to work.  I last tested it about an year ago when lookig at
> http://gnats.netbsd.org/51132

Turns out VBox no longer enables bus-master by default and our driver
never enables it b/c it's always been enabled by default.

qemu had similar fallout too:
http://lists.gnu.org/archive/html/qemu-devel/2014-09/msg02368.html

-uwe