[mywittyname]

> Quoting ARM and AMD is really a bit pathetic too, IMHO, especially if it turns out that AMD chips are immune to the flaw.

The official fix for this in the Linux kernel has a comment that literally says to assume all x86 processors suffer from the same issue and will disable KPTI for all x86 processors, including AMD.

There's an AMD-specific patch that I saw floating around that keeps the setting enabled for AMD processors, but I'm not sure if it made it into the mainline.

[betterunix2]

https://lkml.org/lkml/2017/12/27/2

It makes reference to the nature of the bug and explains why AMD's chips are not affected (from an AMD engineer).

[mywittyname]

I was making reference to this [1].

The original fix had a comment that literally said, "/* Assume for now that ALL x86 CPUs are insecure */" They've since added a check to exclude AMD processors.

[1] https://kernel.googlesource.com/pub/scm/linux/kernel/git/tip...

[betterunix2]

Same patch I think.

[cesarb]

That patch would be this git commit: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/...

Not yet on the mainline AFAIK, but I'd guess that whole branch will be merged soon (before the next release candidate).

[qubex]

I don't know if it's possible to see who contributed that patch (yet), but I’m cynical enough to half-expect that the “assume all x86 processors are insecure” patch might come from an Intel engineer...

[mywittyname]

I would not be surprised at all, considering the patch I saw for the AMD processors was literally a one-line if statement around the set cpu insecure flag that added a check for AMD processors.

Google is failing me or I'd post a link.

[omeid2]

the patch was by Thomas Gleixner[0], who is not an Intel Engineer.

AMD has since pushed a patch to "not enable PTI on AMD processors" [1]

[0] https://patchwork.kernel.org/patch/10138833/

[1] https://patchwork.kernel.org/patch/10142563/

[GalacticDomin8r]

You might mean this one:

https://lkml.org/lkml/2017/12//27/2

[mywittyname]

Yeah.

I just found it in their git repo, looks like it was added today. https://kernel.googlesource.com/pub/scm/linux/kernel/git/tip...

[angelsl]

You mean enable KPTI.