From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.alien8.de (mail.alien8.de [65.109.113.108]) (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 642E92D0635; Tue, 24 Mar 2026 20:01:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=65.109.113.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774382478; cv=none; b=rVggVaqFMxaGpL9Vm/GRhZ5QbqulXtYeEG9OfbPpnsGYcUWwMj5c1r/T6OkTV/cReDSZo2IRGOkJ/NGCVqtfP0Q2pCypcAWMP3KOwCiK9cStbNcph3wGnkJ5RLxeLR9qNK0E7lVhv5jKS63ROXDTOljLRcpHOl1donPuWRMVdqA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774382478; c=relaxed/simple; bh=MPwNHSpoYjyM16ewI+BxbAdvmJMpRdZDXK7CwZ6QIDw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JszMo7icXkoI528blbv37+KOdUPAFRqyG7/9IkaQuVv5x96MSOZMa3gSOnh5qN7mD+2H29wOwcKu/CLBJn3Cl7Czl95kHz5cQGH2wqnmj3AOv0AcLSQ5V0uJvZNjwWVlHxS+/KDpoZbRfWOfO8UU3S5FQwz76E7as0nng1au57g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de; spf=pass smtp.mailfrom=alien8.de; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b=AmcOTFso; arc=none smtp.client-ip=65.109.113.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=alien8.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b="AmcOTFso" Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTP id 8045540E0222; Tue, 24 Mar 2026 20:01:13 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at mail.alien8.de Authentication-Results: mail.alien8.de (amavisd-new); dkim=pass (4096-bit key) header.d=alien8.de Received: from mail.alien8.de ([127.0.0.1]) by localhost (mail.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id vXkONk_xMsOw; Tue, 24 Mar 2026 20:01:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=alien8; t=1774382463; bh=rrltVfsKaUOz3jKzbq8S1z1BNCaZvfoi0wgXPux+LGo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=AmcOTFsokQCadYhgaodHohkOM+Z+rHYntVaJXympYseSn0bmHzpYLQwX3qjT7BO6V Z6n/zj11uUN3AJXlC8IC9gNJoR2Ukj6qmiI+ysggCuy4t+MrUfJytvpXCwzJSb5PtW ov8I1VmsRIj/fKyefGm7/GkvSzS/mRAPFAoo0VQJK68LX1SO+otT0BX8MQMCCVO3Of 7IlSJtnEtuG9RAOWrviSHwm5ciQsS4o8S5CFGpZrQmqcav3px84M7InZF3+mph25nG HPnPlbwaBfj3RNcPuPzBQo/SSzB6C47ArYDzCckZsrU4lY83D3G7bNv8W1RKuMOZsq Hpfhsv+RV+9+jc90O22I+5ltALhblGl4gEfBNUxBzBVtzh6Dei40gfEBxOgkTcyJix NyVAb1KE50NWOBJdXfEiMghOacFkk4/fOrQfHaXTCwHHl5zSuh9mDFU+m50dLyvxjt jngde1ZkfG6vChR3De2mnBZgrFz/3LUgc3HR0i9LLo2dOtrjSkA+/lX4xQRaZ/a7eq XTcPYn8vIK/HvYwYGfYjzmPk8iTNjc39InYjK7AJ/luScpkVfEy4XsAFaKIbn6MNRv 1quh2qbNUCh+aawylKNXtU6eqxyluGDqHcdRgnjnyCGWD8TbH38IIbOyo1bwWtgAw+ asPjanKnk6HRhk9DezGoMurk= Received: from zn.tnic (p5de8e020.dip0.t-ipconnect.de [93.232.224.32]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-256) server-digest SHA256) (No client certificate requested) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with UTF8SMTPSA id 5730B40E0031; Tue, 24 Mar 2026 20:00:27 +0000 (UTC) Date: Tue, 24 Mar 2026 21:00:26 +0100 From: Borislav Petkov To: Pawan Gupta Cc: Peter Zijlstra , x86@kernel.org, Nikolay Borisov , "H. Peter Anvin" , Josh Poimboeuf , David Kaplan , Sean Christopherson , Dave Hansen , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , KP Singh , Jiri Olsa , "David S. Miller" , David Laight , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , David Ahern , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , Stanislav Fomichev , Hao Luo , Paolo Bonzini , Jonathan Corbet , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Asit Mallick , Tao Zhang , bpf@vger.kernel.org, netdev@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [PATCH v7 07/10] x86/vmscape: Use static_call() for predictor flush Message-ID: <20260324200026.GCacLtWmhGVOmz832E@fat_crate.local> References: <20260319-vmscape-bhb-v7-0-b76a777a98af@linux.intel.com> <20260319-vmscape-bhb-v7-7-b76a777a98af@linux.intel.com> <20260319205802.GJ3738786@noisy.programming.kicks-ass.net> <20260319213421.br6na4dulrjm6eke@desk> <20260319214409.GL3738786@noisy.programming.kicks-ass.net> <20260320062206.bdrnmnvho6lhmejw@desk> <20260320090340.GN3738786@noisy.programming.kicks-ass.net> <20260320113134.GAab0wFqe-hewZc175@fat_crate.local> <20260320182308.ahynqzuswlv34wf6@desk> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260320182308.ahynqzuswlv34wf6@desk> On Fri, Mar 20, 2026 at 11:23:08AM -0700, Pawan Gupta wrote: > I am curious, what problems do you anticipate? There are nearly 50 What's easier when you need to change the underlying implementation: unexport the static key and touch a bunch of places in the process or simply change the accessor's body and all the callers don't notice a thing? -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette