Re: [PATCH 5/7] x86/bugs: Only harden syscalls when needed

[Ingo Molnar]

* Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:

> > [...]
> > > @@ -1720,6 +1744,7 @@ static void __init spectre_v2_select_mitigation(void)
> > >  
> > >  	case SPECTRE_V2_CMD_RETPOLINE_LFENCE:
> > >  		pr_err(SPECTRE_V2_LFENCE_MSG);
> > > +		setup_clear_cpu_cap(X86_FEATURE_INDIRECT_SAFE);
> > 
> > I don't know if it intentional, this seems to be the duplicate of
> > X86_FEATURE_INDIRECT_SAFE clear later in SPECTRE_V2_LFENCE mode. Also it
> > seems a bit odd to do this here in SPECTRE_V2_CMD handling.
> 
> Yeah, I accidentally left that in from an earlier implementation.  It's 
> harmless but I'll clean that up too with a new patch unless Ingo wants to 
> remove that line.

Lemme remove it entirely from x86/urgent, so that you can submit an updated 
patch with all feedback included.

In addition to the above line, Pawan's suggestion of doing it in C via 
cpu_feature_enabled() looks quite a bit simpler and easier to read & argue 
about, right?

Thanks,

	Ingo