Re: [PATCH v3 07/15] KVM: MMU: introduce nulls desc

Gleb Natapov
2013-11-25T10:20:19Z

On Mon, Nov 25, 2013 at 02:11:31PM +0800, Xiao Guangrong wrote:
> >
> > For example, nothing prevents lockless walker to move into some
> > parent_ptes chain, right?
>
> No.
>
> The nulls can help us to detect this case, for parent_ptes, the nulls points
> to "shadow page" but for rmaps, the nulls points to slot.arch.rmap. There
> is no chance that the “rmap" is used as shadow page when slot-lock is held.
>
But meanwhile we will write protect non-last level sptes, no? Better to
create separate slab caches for rmap and parent_ptes lists.

--
Gleb.