Re: [RFC KVM 18/27] kvm/isolation: function to copy page table entries for percpu buffer

From: Peter Zijlstra
Date: Tue May 14 2019 - 03:11:29 EST

On Mon, May 13, 2019 at 11:18:41AM -0700, Andy Lutomirski wrote:
> On Mon, May 13, 2019 at 7:39 AM Alexandre Chartre
> <alexandre.chartre@xxxxxxxxxx> wrote:
> >
> > pcpu_base_addr is already mapped to the KVM address space, but this
> > represents the first percpu chunk. To access a per-cpu buffer not
> > allocated in the first chunk, add a function which maps all cpu
> > buffers corresponding to that per-cpu buffer.
> >
> > Also add function to clear page table entries for a percpu buffer.
> >
> This needs some kind of clarification so that readers can tell whether
> you're trying to map all percpu memory or just map a specific
> variable. In either case, you're making a dubious assumption that
> percpu memory contains no secrets.

I'm thinking the per-cpu random pool is a secrit. IOW, it demonstrably
does contain secrits, invalidating that premise.