Re: [RFC PATCH 00/16] PTI support for x86-32

From: Alan Cox
Date: Tue Jan 23 2018 - 09:59:59 EST


On Mon, 22 Jan 2018 09:56:25 +0100
Joerg Roedel <joro@xxxxxxxxxx> wrote:

> Hey Nadav,
>
> On Sun, Jan 21, 2018 at 03:46:24PM -0800, Nadav Amit wrote:
> > It does seem that segmentation provides sufficient protection from Meltdown.
>
> Thanks for testing this, if this turns out to be true for all affected
> uarchs it would be a great and better way of protection than enabling
> PTI.
>
> But I'd like an official statement from Intel on that one, as their
> recommended fix is still to use PTI.
>
> And as you said, if it turns out that this works only on some Intel
> uarchs, we can also detect it at runtime and then chose the fasted
> meltdown protection mechanism.

I'll follow this up and get an official statement.

Alan