On Thu, Mar 12, 2020 at 02:32:11AM -0400, Michael S. Tsirkin wrote: > On Thu, Mar 12, 2020 at 12:10:49PM +1100, David Gibson wrote: > > On Wed, Mar 11, 2020 at 03:33:59AM -0400, Michael S. Tsirkin wrote: > > > On Wed, Mar 11, 2020 at 12:12:47PM +1100, David Gibson wrote: > > > > I am wondering if we have to introduce an "svm=on" flag anyway. It's > > > > pretty ugly, since all it would be doing is changing defaults here and > > > > there for compatibilty with a possible future SVM transition, but > > > > maybe it's the best we can do :/. > > > > > > Frankly I'm surprised there's no way for the hypervisor to block VM > > > transition to secure mode. To me an inability to disable DRM looks like > > > a security problem. > > > > Uh.. I don't immediately see how it's a security problem, though I'm > > certainly convinced it's a problem in other ways. > > Well for one it breaks introspection, allowing guests to hide > malicious code from hypervisors.
Hm, ok. Is that much used in practice?
(Aside: I don't think I'd call that "introspection" since it's one
thing examining another, not something examining itself).
>
> > > Does not the ultravisor somehow allow
> > > enabling/disabling this functionality from the hypervisor?
> >
> > Not at present, but as mentioned on the other thread, Paul and I came
> > up with a tentative plan to change that.
> >
> > > It would be
> > > even better if the hypervisor could block the guest from poking at the
> > > ultravisor completely but I guess that would be too much to hope for.
> >
> > Yeah, probably :/.
> >
>
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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