Re: [patch 2/2] x86/tsc: Force TSC_ADJUST register to value >= zero

[Ingo Molnar]

* Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:

> We have two options:
> 
> 1) Disable TSC deadline timer by default and force users with sane machines
>    to enable it on the kernel command line.
> 
>    Upside:   Very small patch
>    
>    Downside: Degrades existing setups on sane machines, keeps TSC unusable
>       	     on affected machines. We have no idea what other hidden side
>       	     effects the TSC_ADJUST tinkering has. If there are any, they
>       	     ain't be nice ones.
> 
> 2) Push the whole TSC_ADJUST sanitizing machinery into stable
> 
>    Upside:   Does not affect sane machines and gives a benefit to users of
>    	     affected machines
> 
>    Downside: Rather large patch, but not that risky either. Needs a few
> 	     eyes and good test coverage though
> 
> Thoughts?

I'd go for #2, because #1 is essentially turning it off for almost everyone.

We can still do #1 and push it back to -stable as well if #2 fails.

But I'd suggest we delay the stable backporting until it's been upstream a bit.

Thanks,

	Ingo