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Date: Fri, 19 Apr 2024 15:38:46 +0100
From: Will Deacon <will@kernel.org>
To: Sean Christopherson <seanjc@google.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	Jonathan Corbet <corbet@lwn.net>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Josh Poimboeuf <jpoimboe@kernel.org>, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
	Daniel Sneddon <daniel.sneddon@linux.intel.com>,
	linuxppc-dev@lists.ozlabs.org, linux-arch@vger.kernel.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	Heiko Carstens <hca@linux.ibm.com>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>
Subject: Re: [PATCH 1/3] x86/cpu: Actually turn off mitigations by default
 for SPECULATION_MITIGATIONS=n
Message-ID: <20240419143846.GA3508@willie-the-truck>
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On Fri, Apr 19, 2024 at 07:06:00AM -0700, Sean Christopherson wrote:
> On Fri, Apr 19, 2024, Will Deacon wrote:
> > On Mon, Apr 15, 2024 at 07:31:23AM -0700, Sean Christopherson wrote:
> > > On Mon, Apr 15, 2024, Geert Uytterhoeven wrote:
> > > Oof.  I completely missed that "cpu_mitigations" wasn't x86-only.  I can't think
> > > of better solution than an on-by-default generic Kconfig, though can't that it
> > > more simply be:
> > > 
> > > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
> > > index 2b8fd6bb7da0..5930cb56ee29 100644
> > > --- a/drivers/base/Kconfig
> > > +++ b/drivers/base/Kconfig
> > > @@ -191,6 +191,9 @@ config GENERIC_CPU_AUTOPROBE
> > >  config GENERIC_CPU_VULNERABILITIES
> > >         bool
> > >  
> > > +config SPECULATION_MITIGATIONS
> > > +       def_bool !X86
> > > +
> > >  config SOC_BUS
> > >         bool
> > >         select GLOB
> > 
> > I can't see this in -next yet. Do you plan to post it as a proper patch
> > to collect acks etc?
> 
> Sorry, I neglected to Cc everyone.
> 
> https://lore.kernel.org/all/20240417001507.2264512-2-seanjc@google.com

Ah, thanks. I'll go Ack that...

Will