Re: tip/master falls off NOP cliff with KPTI under KVM

[Woodhouse, David]

On Thu, 2018-01-11 at 01:34 +0300, Alexey Dobriyan wrote:
> 
> Bisection points to
> 
> ÂÂÂÂÂÂÂÂf3433c1010c6af61c9897f0f0447f81b991feac1 is the first bad commit
> ÂÂÂÂÂÂÂÂcommit f3433c1010c6af61c9897f0f0447f81b991feac1
> ÂÂÂÂÂÂÂÂAuthor: David Woodhouse <dwmw@xxxxxxxxxxxx>
> ÂÂÂÂÂÂÂÂDate:ÂÂ Tue Jan 9 14:43:11 2018 +0000
> 
> ÂÂÂÂÂÂÂÂÂÂÂ x86/retpoline/entry: Convert entry assembler indirect jumps

Thanks. We've fixed the underlying problem with the alternatives
mechanism, *and* changed the retpoline code not to actually rely on
said fix.

> RETPOLINE is enabled but build system is reporting that compiler doesn't
> support it (Gentoo 6.4.0 p1.1)
> 
> Disabling CONFIG_RETPOLINE fixes boot.
> 
> And build system reports that "system may be insecure" even if RETPOLINE
> is disabled.

That's odd. The warning is *inside* 'ifdef CONFIG_RETPOLINE'...

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