[Development] Broken RNG on AMD Ryzen CPUs affect QTemporaryFile, Qt IFW

Thiago Macieira thiago.macieira at intel.com
Wed Feb 19 23:41:24 CET 2020


On Wednesday, 19 February 2020 08:26:56 PST Konstantin Ritt wrote:
> Should we ever try to work around issues caused by broken CPUs? Maybe we
> should warn the user instead (with big red banner) and decline to install
> anything at all?

That was the thinking on the first task. We thought it was a small corner case 
and that it would be simply fixed by the few people with a BIOS upgrade.

When it turned out to be much more widespread and systemd also worked around 
it, we did too.

> > <snip /> (or buy Intel)
> 
> Or let's maybe also try to work around Meltdown and Spectre on i, just for
> symmetry? ;)

a) we don't have to for most of Qt, since the mitigations for them are done in 
the kernel and microcode updates already. The only exception is anything that 
JITs untrusted sources. Namely, qtwebengine. But I believe the mitigations are 
already present in the Chromium sources we use.

b) Spectre (one of the two or both) also affects AMD and ARM and every single 
out-of-order processor system out there. Please see the technical docs for 
more information.


-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel System Software Products





More information about the Development mailing list