AMD FW13 BIOS disable SMT option

Hi developers,

I hope you all are doing well.
Currently, AMD and Intel processors are plagued with security issues with regards to Simultaneous Multithreading (SMT).

Of course, the solution would be to disable SMT. However, I haven’t been able to find any option for Windows to disable SMT.
The next step would be to disable SMT through BIOS. We then run into another problem; AMD FW13 does not have an option to disable SMT.

I wonder if it would be possible to include an option to disable SMT on all FW laptops.

Cheers

Is this worse than Intel management engine?

You mean SQUIP from 2 years ago or something new? That one doesn’t seem like a huge deal to me since non constant time crypto has so many other side-channel attack vectors, this one is just potentially a little faster.

You should be able to disable smt using smokeless if it’s really important to you but I do think it would be neat if framework added this very basic setting to the bios.

As in there are actual proof of concepts for using it, yes, though they are 2 very different things.

For a long time I’ve not been a fan of SMT, but let’s skip over the details of why. I’m running linux so I found I can add nosmt=force to kernel args. And it worked great, the laptop was responsive, etc. But it turned out that this setting made s2idle not work right, and taking that setting back out dramatically decreased battery usage during suspend. So I’ve just accepted using SMT on this system, it’s how it was designed and debugged (and operating systems are pretty good at avoiding most of the SMT weaknesses by now).

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