Is hyper-threading still an issue

[ticojohn]

I hate to beat an old horse but am wondering if the latest intel-microcode mitigates the issues with what I think Microsoft calls MDS.
I am running Buster on one drive and Bullseye on two other drives. I have hyper-threading turned off in the bios on my Gigabyte motherboard and implemented mitigations=auto,nosmt in grub on my Intel NUC. I don't play "games" and use the NUC mostly for watching videos. I don't seem to have any issues streaming videos but just wonder if it is safe to enable hyper-threading, and even more would I really benefit from doing so?

[stevepusser]

Experts worry mostly about attacks coming over the Net. If you're not connected, there's not much to worry about.

Many consider it inherently insecure if you are connected, though.

[Head_on_a_Stick]

wondering if the latest intel-microcode mitigates the issues with what I think Microsoft calls MDS

Enable SMT from the firmware ("BIOS") setting and ask the kernel what it thinks:

Code: Select all

cat /sys/devices/system/cpu/vulnerabilities/mds

But it's probably worth noting that SMT is a potential source for other, as yet undiscovered, vulnerabilities. The OpenBSD developers decided to disable SMT by default for this exact reason when Metldown & Spectre were first announced and they were proved right when MDS was found later.

https://www.mail-archive.com/source-cha ... 99141.html

[ticojohn]

Enable SMT from the firmware ("BIOS") setting and ask the kernel what it thinks:

Code: Select all

cat /sys/devices/system/cpu/vulnerabilities/mds

Yep, it's an issue. Hyper-threading was already enabled in the BIOS, I disabled it in grub using mitigations=auto,nosmt.
Why did I do it that way? Because it is a pain in the backside to get into BIOS on my NUC. The NUC BIOS only supports a 1024x768 screen resolution and my non-smart TV does not support that resolution.

As always, thanks for your feedback.