Re: [PATCH] x86/tsc: Add debugfs entry to mark TSC as unstable after boot

From: Guilherme G. Piccoli
Date: Sun Mar 23 2025 - 15:22:16 EST


On 23/03/2025 15:14, Borislav Petkov wrote:
> On Sun, Mar 23, 2025 at 02:53:05PM -0300, Guilherme G. Piccoli wrote:
>> But what about AMD systems? Even the modern ones apparently lack
>> TSC_ADJUST - or is it changing recently?
>
> Yes, it is.

This is great to hear - is there any starting point model that you know
AMD introduced/is introducing TSC_ADJUST?


>
> The only one I know of is a Zen2 laptop where BIOS botches a perfectly fine
> TSC because those BIOS programmers are soo smart.
>
> If you know of other cases, where are those bug reports?
>

We don't know yet what's going on, some TSC skews reported eventually in
some machines, in a fleet - but "old" processors, Zen 1st gen.
Once things are more clear, definitely could provide a more mature
report of the issue.

Cheers,


Guilherme