Re: l1tf: Kernel suggests I throw away third of my memory. I'd rather not

[Michal Hocko]

On Wed 17-10-18 13:32:26, Pavel Machek wrote:
[...]
> > > Now question is... can we do better? Kernel stores information about
> > > swapped-out pages there, right? That sounds like a cool hack, but
> > > maybe it is time to get rid of that hack?
> > 
> > Patches are welcome.
> 
> Cooperation will be needed if you want to see patches. As
> in... answering the questions above.

The question is whether that is really worth it. L1TF is mostly about
virtual environments. If you are running in a native HW then I wouldn't
lose much sleep over it. a) pfns stored in PROT_NONE entries are
controlled by the OS b) swap based attacks with something interesting in
L1$ colliding with the swap entry is theoretical at best.
-- 
Michal Hocko
SUSE Labs