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 C998AC433F5 for ; Mon, 7 Mar 2022 17:13:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233763AbiCGROU (ORCPT ); Mon, 7 Mar 2022 12:14:20 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41694 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231767AbiCGROT (ORCPT ); Mon, 7 Mar 2022 12:14:19 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id DEF1641324 for ; Mon, 7 Mar 2022 09:13:24 -0800 (PST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A2F87153B; Mon, 7 Mar 2022 09:13:24 -0800 (PST) Received: from monolith.localdoman (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 585883FA45; Mon, 7 Mar 2022 09:13:21 -0800 (PST) Date: Mon, 7 Mar 2022 17:13:50 +0000 From: Alexandru Elisei To: Marc Zyngier Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Andre Przywara , Christoffer Dall , Jintack Lim , Haibo Xu , Ganapatrao Kulkarni , Chase Conklin , "Russell King (Oracle)" , James Morse , Suzuki K Poulose , karl.heubaum@oracle.com, mihai.carabas@oracle.com, miguel.luis@oracle.com, kernel-team@android.com Subject: Re: [PATCH v6 43/64] KVM: arm64: nv: arch_timer: Support hyp timer emulation Message-ID: References: <20220128121912.509006-1-maz@kernel.org> <20220128121912.509006-44-maz@kernel.org> <8735jt1z9c.wl-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8735jt1z9c.wl-maz@kernel.org> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hi, On Mon, Mar 07, 2022 at 04:52:15PM +0000, Marc Zyngier wrote: > On Mon, 07 Mar 2022 16:28:44 +0000, > Alexandru Elisei wrote: > > > > Hi, > > > > On Mon, Mar 07, 2022 at 03:48:19PM +0000, Marc Zyngier wrote: > > > On 2022-03-07 14:52, Alexandru Elisei wrote: > > > > Hi, > > > > > > > > I was under the impression that KVM's nested virtualization doesn't > > > > support > > > > AArch32 in the guest, why is the subject about hyp mode aarch32 timers? > > > > > > Where did you see *ANY* mention of AArch32? > > > > I saw an implicit mention of aarch32 when the commit message used > > the term "hyp", which is the name of an aarch32 execution mode. > > > > > > > > Or is that a very roundabout way to object to the 'hyp' name? > > > > Bingo. > > > > > If that's the case, just apply a mental 's/hyp/el2/' substitution. > > > > I'm a bit confused about that. Is that something that anyone reading > > the patch should apply mentally when reading the patch, or is it > > something that you plan to change in the commit subject? > > Big picture: > > maz@hot-poop:~/arm-platforms$ git grep -i hyp arch/arm64/|wc -l > 1701 > maz@hot-poop:~/arm-platforms$ git grep -i el2 arch/arm64/|wc -l > 1008 > > Are we going to also repaint all these 'hyp' references? I didn't say, nor suggest that. I suggested that *this* commit could be changed to use the architectural terminology, which I assumed it's the most natural terminology to use in a patch series which has the goal to emulate the architectural EL2. Obviously, opinions vary. > > I really appreciate all the hard work you are putting in carefully > reviewing the code. I *really* do. But bickering on this really > doesn't help, and I know you understand exactly what this subject line > means (you've been reviewing KVM code for long enough, and won't fool > anyone). > > The point you are trying to make really is moot. Everybody understands > that HYP means EL2. I'd even argue that it is clearer than EL2, > because it indicates that we're running at EL2 with the role of a > hypervisor, which isn't that clear with running with VHE. So HYP means EL2 or EL2 with the role of a hypervisor? Because when booting KVM on a machine without FEAT_VHE, dmesg uses "hyp mode" to refer to EL2 without FEAT_VHE. And is_hyp_ctxt(), which this series adds, refers to EL0 with HCR_EL2.TGE set. I've given these examples before (and others), in the end it's up to you how precise you want the terminology to be and how easy to understand you want to make the code. Thanks, Alex