Re: [PATCH] virtio_net: validate device stats reply records before use

On Sat, Jul 11, 2026 at 11:29:56AM -0400, Michael Bommarito wrote:
> On Sat, Jul 11, 2026 at 11:20 AM Michael S. Tsirkin <[email protected]> wrote:
> > Why does it "matter most", or at all, there?
> > Host can always deny guest service. In fact, this is how cloud vendors
> > charge their clients, by denying service to whoever did not pay them.
> ...
> > I'm all for making things easier to debug even when the device is buggy.
> > But I'm not inclined to add tons of hard to maintain code to
> > that end, and I would be worried broken hosts will come to
> > rely on drivers working around them.
> 
> I am always confused by the CoCo threat model to be honest,

Confidential computing? It's vague at points, given the term covers a
lot of different hardware. But one thing is clear - it's about
confidentiality.  DoS by host is empathically outside the threat model.
On any virtualization platform I know without exception,
host can just exit the VM, done, service denied.

> since it
> seems like some people care a lot about maximalist reliance on the
> contract and other people are more practical about how many other
> vectors exist anyway.

I don't really know what "vectors" or "the contract" are here.

Making a guest recover from a misbehaving device has as much a chance
to reduce security as increase it. So the only benefit is
robustness for users/developers, not security. And that
has to be weighted against the maintainance cost of the change.
This one is too costly, I judge.

>  No hard feelings if you want to NACK, but at
> least it's documented publicly now for people to consider.
> 
> Thanks,
> Mike