Re: [Qemu-devel] [PATCH 1/1] virtio: fail device if set_event_notifier fails

[Cornelia Huck]

On Fri, 3 Mar 2017 13:43:32 +0100
Halil Pasic <address@hidden> wrote:

> On 03/03/2017 01:21 PM, Cornelia Huck wrote:
> > On Thu,  2 Mar 2017 19:59:42 +0100
> > Halil Pasic <address@hidden> wrote:
> > 
> >> The function virtio_notify_irqfd used to ignore the return code of
> >> event_notifier_set. Let's fail the device should this occur.
> > 
> > I'm wondering if there are reasons for event_notifier_set() to fail
> > beyond "we've hit an internal race and should make an effort to fix
> > that one, or else we have completely messed up in qemu". Marking the
> > device broken tells the guest that there's something wrong with the
> > device, but I think we want qemu bug reports when there's something
> > broken with the irqfd.
> >
> 
> That's why the error is logged. I understand virtio_error like something
> suitable for indicating bugs.
> 
> What do you suggest? Forcing a dump? I would rather leave it to the
> user to figure out how important is the state sitting in the machine
> and the device, and how much effort does (s)he want to put into recovering
> from the failure. 

How likely are those logged messages being brought to attention of the
admin? Does any management software flag machines with such error
messages? (that's more of a general question)

I'd like to have some kind of trigger that rings an alarm bell so that
the admin might consider reporting this, but I don't have a good idea
on how to do that either...