Re: [Qemu-devel] [PATCH] vhost-scsi: Update 'ioeventfd_started' with host notifiers

[Paolo Bonzini]

On 07/11/2016 18:26, Felipe Franciosi wrote:
> > @@ -95,6 +95,7 @@ static int vhost_scsi_start(VHostSCSI *s)
> >     if (ret < 0) {
> >         return ret;
> >     }
> > +    VIRTIO_BUS(qbus)->ioeventfd_started = true;
> 
> I'm not sure if it's safe to do this from
> vhost_dev_disable/enable_notifiers() directly. If you'd rather this
> is fixed there, please let me know and I'll send a v2. This e-mail is
> basically to flag a problem which I recently came across when working
> on vhost-user-scsi. Basically my code stopped working and I didn't
> know why, so I rolled back to test a traditional vhost-scsi on master
> and found this.
> 
> I have also not tested vhost-sock, but I imagine it might suffer from
> the same issue (even if it doesn't manifest itself this easily). Any
> other cases you can think of?

Hi Felipe,

can you try overriding start_ioeventfd and stop_ioeventfd (like
ad07cd69ecaffbaa015459a46975ab32e50df805 for regular virtio-scsi), so
that they point to vhost_scsi_start and vhost_scsi_stop?  You should not
even need vhost_scsi_set_status anymore.

I'm not sure however why vhost-vsock checks vdev->vm_running, but
otherwise the same should apply to vhost-vsock as well.

Thanks,

Paolo