Re: [PATCH 1/3] Add prctl commands PR_GET_TSC and PR_SET_TSC

[H. Peter Anvin]

Andi Kleen wrote:
> > I think what Erik is trying to do is to make it possible to disable as
> > many of these in the kernel as possible; I/O is easy, it's off by
> > default; RDTSC and RDPMC can be disabled in the kernel, and I think
> > even XSTORE can be disabled.
>
> I'm a little sceptical it will work reliably, but we'll see.
>
> There's also LSL (forgot that earlier). It is used by the vgetcpu()
> because it's faster than CPUID or RDTSCP. Kernel
> sets a magic segment up which has different limits for different CPUs.

Yeah, that's unlikely to be found in code that isn't actively looking 
for it, though.

	-hpa
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