From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6BDC3273D91; Thu, 10 Jul 2025 15:47:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752162447; cv=none; b=NNLBrd54ohbEF6MY088slpn/qAU+PheTcGR7mzqKrmbD0Os2PXweJK+7umafLdCctl6moMxIdMOKpctIIwr4vF/mpFnOGCfhnCxAqofW6deQlzePdz7SIJzMjF5a5q1mfjUH2b8znq6XbFUKHK63wg+2RhNknuwboTQLHFmeRak= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752162447; c=relaxed/simple; bh=CG10AydbLDKiz7iLm8kpbdO5TAZItghs/0FO7lh9rLU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=g9pN9hpSgFZY67Bxmjj7kHkk8w1uqZei50vZhyKspu/m6Zoe1uhbL4NSlEMckSopWco4iCV/hnewoU3uGdyIvU7EWoR6+q3PT+nmyCqCeCg7kvtiBXyeOsxTSP56YbchjaGmryF1Udx2/s9UnR8pYKxumTkHbFX0FwfHYMdDHHw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=Smmq2eq8; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Smmq2eq8" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=bZxu+DQfctNogwYpaOLz3JI+YiDCl8GgvQ6csZ2gybM=; b=Smmq2eq8bLmDm8uRIhrsL1Iz+i KDfeleHWzqJbwBBqrzQw8bqxlDE3NNE+UH5P9hCLxdYEkm2uenfLix3GBBM5cJAi4xifIlZb5RGX4 qp/6ggvpcg+pspjWyCcGZm9BFrgKIEc1rNSckMye0oibhVr8SyHjv2YuMS8Tur+gMoiVE/zGFR7ae OmutweWxlh7yvdVHcv16t6DNs7rWFQQTL2qoPAuTix1NsYkTQyXDetxhVA/kuXT3e2k5N/zKNFT1G ngUJqDsD5rORXZxA1Nwsl6POiRzriZcdONDtiC4Xv1vKvdr2+QDSwvw6B5vtbl+/DDdkOSSf8zx6I iSkVuDDg==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1uZtUI-00000009438-0aQX; Thu, 10 Jul 2025 15:47:06 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 05E1B30023C; Thu, 10 Jul 2025 17:47:05 +0200 (CEST) Date: Thu, 10 Jul 2025 17:47:04 +0200 From: Peter Zijlstra To: Borislav Petkov Cc: Sean Christopherson , Thomas Gleixner , Ingo Molnar , Dave Hansen , x86@kernel.org, Paolo Bonzini , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, dri-devel@lists.freedesktop.org, Kevin Loughlin , Tom Lendacky , Kai Huang , Ingo Molnar , Zheyun Shen , Mingwei Zhang , Francesco Lavra Subject: Re: [PATCH v3 3/8] x86, lib: Add WBNOINVD helper functions Message-ID: <20250710154704.GJ1613633@noisy.programming.kicks-ass.net> References: <20250522233733.3176144-1-seanjc@google.com> <20250522233733.3176144-4-seanjc@google.com> <20250710112902.GCaG-j_l-K6LYRzZsb@fat_crate.local> <20250710143729.GL1613200@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250710143729.GL1613200@noisy.programming.kicks-ass.net> On Thu, Jul 10, 2025 at 04:37:29PM +0200, Peter Zijlstra wrote: > On Thu, Jul 10, 2025 at 01:29:02PM +0200, Borislav Petkov wrote: > > On Thu, May 22, 2025 at 04:37:27PM -0700, Sean Christopherson wrote: > > > diff --git a/arch/x86/lib/cache-smp.c b/arch/x86/lib/cache-smp.c > > > index 079c3f3cd32c..1789db5d8825 100644 > > > --- a/arch/x86/lib/cache-smp.c > > > +++ b/arch/x86/lib/cache-smp.c > > > @@ -19,3 +19,14 @@ void wbinvd_on_all_cpus(void) > > > on_each_cpu(__wbinvd, NULL, 1); > > > } > > > EXPORT_SYMBOL(wbinvd_on_all_cpus); > > > + > > > +static void __wbnoinvd(void *dummy) > > > +{ > > > + wbnoinvd(); > > > +} > > > + > > > +void wbnoinvd_on_all_cpus(void) > > > +{ > > > + on_each_cpu(__wbnoinvd, NULL, 1); > > > +} > > > +EXPORT_SYMBOL(wbnoinvd_on_all_cpus); > > > > If there's no particular reason for the non-GPL export besides being > > consistent with the rest - yes, I did the change for wbinvd_on_all_cpus() but > > that was loooong time ago - I'd simply make this export _GPL. > > Uhhhh, how about we use this fancy export to known modules only thing > for this? > > These are typical things we do *NOT* want people to actually use. So kvm-amd is the SEV stuff, AGPGART is the ancient crap nobody cares about, CCP is more SEV stuff, DRM actually does CLFLUSH loops, but has a WBINVD fallback. i915 is rude and actually does WBINVD. Could they pretty please also do CLFLUSH loops? Anyway, the below seems to survive an allmodconfig. --- diff --git a/arch/x86/lib/cache-smp.c b/arch/x86/lib/cache-smp.c index c5c60d07308c..ac3cc32a4054 100644 --- a/arch/x86/lib/cache-smp.c +++ b/arch/x86/lib/cache-smp.c @@ -12,19 +12,19 @@ void wbinvd_on_cpu(int cpu) { smp_call_function_single(cpu, __wbinvd, NULL, 1); } -EXPORT_SYMBOL(wbinvd_on_cpu); +EXPORT_SYMBOL_GPL_FOR_MODULES(wbinvd_on_cpu, "kvm-amd,agpgart,ccp,drm,i915"); void wbinvd_on_all_cpus(void) { on_each_cpu(__wbinvd, NULL, 1); } -EXPORT_SYMBOL(wbinvd_on_all_cpus); +EXPORT_SYMBOL_GPL_FOR_MODULES(wbinvd_on_all_cpus, "kvm-amd,agpgart,ccp,drm,i915,intel-gtt"); void wbinvd_on_cpus_mask(struct cpumask *cpus) { on_each_cpu_mask(cpus, __wbinvd, NULL, 1); } -EXPORT_SYMBOL_GPL(wbinvd_on_cpus_mask); +EXPORT_SYMBOL_GPL_FOR_MODULES(wbinvd_on_cpus_mask, "kvm,kvm-amd,agpgart,ccp,drm,i915"); static void __wbnoinvd(void *dummy) { @@ -35,10 +35,10 @@ void wbnoinvd_on_all_cpus(void) { on_each_cpu(__wbnoinvd, NULL, 1); } -EXPORT_SYMBOL_GPL(wbnoinvd_on_all_cpus); +EXPORT_SYMBOL_GPL_FOR_MODULES(wbnoinvd_on_all_cpus, "kvm-amd,agpgart,ccp,drm,i915"); void wbnoinvd_on_cpus_mask(struct cpumask *cpus) { on_each_cpu_mask(cpus, __wbnoinvd, NULL, 1); } -EXPORT_SYMBOL_GPL(wbnoinvd_on_cpus_mask); +EXPORT_SYMBOL_GPL_FOR_MODULES(wbnoinvd_on_cpus_mask, "kvm-amd,agpgart,ccp,drm,i915");