linux-kernel - Re: [Patch v5 09/16] x86/smt: Convert cpu_smt_control check to cpu_smt

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Message-ID: <alpine.DEB.2.21.1811191358210.1537@nanos.tec.linutronix.de>
Date:   Mon, 19 Nov 2018 13:59:29 +0100 (CET)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Tim Chen <tim.c.chen@...ux.intel.com>
cc:     Jiri Kosina <jikos@...nel.org>,
        Tom Lendacky <thomas.lendacky@....com>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        David Woodhouse <dwmw@...zon.co.uk>,
        Andi Kleen <ak@...ux.intel.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Casey Schaufler <casey.schaufler@...el.com>,
        Asit Mallick <asit.k.mallick@...el.com>,
        Arjan van de Ven <arjan@...ux.intel.com>,
        Jon Masters <jcm@...hat.com>,
        Waiman Long <longman9394@...il.com>,
        LKML <linux-kernel@...r.kernel.org>, x86@...nel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [Patch v5 09/16] x86/smt: Convert cpu_smt_control check to
 cpu_smt_enabled static key

On Mon, 19 Nov 2018, Thomas Gleixner wrote:

> Tim,
> 
> On Fri, 16 Nov 2018, Tim Chen wrote:
> >  
> > +static char *l1tf_show_smt_vulnerable(void)
> > +{
> > +	if (static_branch_likely(&cpu_smt_enabled))
> > +		return "vulnerable";
> > +	else
> > +		return "disabled";
> 
> so an UP kernel will now report vulnerable.

Actually it will not do that because the UP build fails in the linker
stage.

arch/x86/Kconfig:       select HOTPLUG_SMT                      if SMP

Thanks,

	tglx