From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 80827C433EF for ; Thu, 6 Jan 2022 19:25:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243298AbiAFTZr (ORCPT ); Thu, 6 Jan 2022 14:25:47 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:56524 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243233AbiAFTZn (ORCPT ); Thu, 6 Jan 2022 14:25:43 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3FB6461CDB for ; Thu, 6 Jan 2022 19:25:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9AA28C36AE3; Thu, 6 Jan 2022 19:25:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1641497142; bh=e+zVGMdRgQtMmKwfhtdxBIqK2ceC0hG3GaW4NSts81k=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=N6lS+k87Foi9gULzBKkVaNpb1rKzSA6ZSqxu5sxJUliLChxFU7dtu7ziNZows8PaR IeyjwiemV08HZKUMNxF16jhi8nywYmaKBy0hQmVtdr8sVg2QXoCBXsrGD82LezIiJ8 C0ec5YT9AnniTBJNhrqh3nBIfdDiuH1ljryFtKS4tRr2qg9U6Qp/ToYgKBY/jJmODo VztzWl4wseoNyb/SJW407mZLj+uE/jjbRpxuX9QguRZJbjeP9CgUhZFRAtASXEtnZx rcs4VQ2ZyoAyfz636VYoRXiTtGdrUAvEQdZrXVPiTt1ZKxzPgZJtZ4B4QZs31sXt95 /sxYgSoRpwHYA== Received: from sofa.misterjones.org ([185.219.108.64] helo=wait-a-minute.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1n5YOK-00GPzM-Lm; Thu, 06 Jan 2022 19:25:40 +0000 Date: Thu, 06 Jan 2022 19:25:42 +0000 Message-ID: <874k6gzmx5.wl-maz@kernel.org> From: Marc Zyngier To: Richard Henderson Cc: qemu-devel@nongnu.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, kernel-team@android.com, Eric Auger , Andrew Jones , Peter Maydell Subject: Re: [PATCH v2] hw/arm/virt: KVM: Enable PAuth when supported by the host In-Reply-To: <364fc879-4b13-cf37-53e0-628a843c7bfa@linaro.org> References: <20220103180507.2190429-1-maz@kernel.org> <87czl5usvb.wl-maz@kernel.org> <3db95713-2f05-3c70-82b1-7e12c579d3e2@linaro.org> <875yqwvkm1.wl-maz@kernel.org> <364fc879-4b13-cf37-53e0-628a843c7bfa@linaro.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: richard.henderson@linaro.org, qemu-devel@nongnu.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, kernel-team@android.com, eric.auger@redhat.com, drjones@redhat.com, peter.maydell@linaro.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Thu, 06 Jan 2022 18:26:29 +0000, Richard Henderson wrote: > > Mm. It does beg the question of why KVM exposes multiple bits. If > they must be tied, then it only serves to make the interface more > complicated than necessary. We would be better served to have a > single bit to control all of PAuth. In hindsight, there is a lot I would change in the KVM userspace ABI, and a lot I should have pushed back on. Unfortunately, there is little we can do now to fix it (userspace expecting this behaviour has been in the wild for almost 3 years already). M. -- Without deviation from the norm, progress is not possible.