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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 737B5C87FD3 for ; Wed, 6 Aug 2025 18:37:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: References:In-Reply-To:Subject:Cc:To:From:Message-ID:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Nf5xRzIvrD/erlICip7y/plqC3VK4lQKuWMoYjmskhY=; b=HpuNMxBzRQfDdyADK2oKTa0YS0 R0Tc6ol+gprJ1T9ghzNHLTag4bXuQ/yWnbfwt8UUdTyvL+qIM86OSd/K/sPU/mB1b07qoa6ByxzzE gTWvDfH8K0ve00AZfX57QUyIAtzDDJWPipIFQPeE2jdvJbpDpA+6Wgi07BQkdrq7c3aEyBEUuzowH FYuJyiOjkZxKtrAdccx9+IwiMVFpGEfTEq2+N7OIrVlGrGo4N16HIl8M4RAdhUsRw1nwkWxGDRUqA EP1+h/KY2sAEnWgzJzGkq8BgE9eHmJ8MHeoHfGEiXNnCNIxyjVSSwySQRHag1rZ9SO3iJQtRX4mL1 yIHae5bA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1ujj0n-0000000G5e8-3Xe0; Wed, 06 Aug 2025 18:37:17 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1ujihy-0000000G2oL-3J3T for linux-arm-kernel@lists.infradead.org; Wed, 06 Aug 2025 18:17:51 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 420FC5C68F7; Wed, 6 Aug 2025 18:17:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DCE12C4CEE7; Wed, 6 Aug 2025 18:17:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754504269; bh=tVIrd2LQ/c5yfLuLbK0Jf7K+0CkcqrpV21ilXh3nK5k=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=rZfFaFrwU6qL+9ZE0ASZ5cNSr6koitnX281KevotnTPKlJE233FzggbjHqabqwmzg 5NLhs5hKzeArAkmK/7swlRbw3dK4PZkemlJSZiqn3LQy870E/EJNjWrZ6gVE+Hp6c/ lBK8n57cR0dC2bu0geA4+XXbK9N6iiNGGiatGJz+N9uU9QLUYQxurXNo1z7YlL/Oxa Ee2qlKpw280FaqWBnqKOX0T4G4KrVEdVnc6keWFE9EsEzhcPFIm1WHm9R28DlcSQ3d L3CoTg+q0OAavRIy9f+KT2LgnEpDScREfHMGjerwd2DMJEdrJRzvNx6W1dqaX8gFYq y+oOJn3Fbwvhg== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1ujihv-004bCc-Ka; Wed, 06 Aug 2025 19:17:47 +0100 Date: Wed, 06 Aug 2025 19:17:47 +0100 Message-ID: <867bzg9uwk.wl-maz@kernel.org> From: Marc Zyngier To: Oliver Upton Cc: Volodymyr Babchuk , "linux-arm-kernel@lists.infradead.org" , "kvmarm@lists.linux.dev" , "linux-kernel@vger.kernel.org" , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon Subject: Re: [PATCH v1 1/2] KVM: arm64: nv: fix S2 translation for nVHE guests In-Reply-To: References: <20250806141707.3479194-1-volodymyr_babchuk@epam.com> <20250806141707.3479194-2-volodymyr_babchuk@epam.com> 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/30.1 (aarch64-unknown-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: oliver.upton@linux.dev, Volodymyr_Babchuk@epam.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250806_111750_902931_0DFAAFB7 X-CRM114-Status: GOOD ( 24.07 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, 06 Aug 2025 18:37:34 +0100, Oliver Upton wrote: > > Hi Volodymyr, > > Thanks for catching this. > > On Wed, Aug 06, 2025 at 02:17:55PM +0000, Volodymyr Babchuk wrote: > > According to ARM architecture specification (ARM DDI 0487 L.a, section > > C5.4.3), Stage 2 translation should be skipped when VHE is active, or, > > in other words, E2H bit is set. Fix the code by inverting both check > > and comment. > > > > Signed-off-by: Volodymyr Babchuk > > --- > > arch/arm64/kvm/at.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c > > index a25be111cd8f8..5e7c3fb01273c 100644 > > --- a/arch/arm64/kvm/at.c > > +++ b/arch/arm64/kvm/at.c > > @@ -1412,10 +1412,10 @@ void __kvm_at_s12(struct kvm_vcpu *vcpu, u32 op, u64 vaddr) > > return; > > > > /* > > - * If we only have a single stage of translation (E2H=0 or > > + * If we only have a single stage of translation (E2H=1 or > > * TGE=1), exit early. Same thing if {VM,DC}=={0,0}. > > */ > > - if (!vcpu_el2_e2h_is_set(vcpu) || vcpu_el2_tge_is_set(vcpu) || > > + if (vcpu_el2_e2h_is_set(vcpu) || vcpu_el2_tge_is_set(vcpu) || > > The check should be HCR_EL2. == '11'. Maybe instead: > > /* > * Exit early if we only have a single stage of translation > * either because we're in the EL2&0 translation regime or > * stage-2 translation is disabled (i.e. HCR_EL2.{VM,DC}=={0,0}). > */ > if (compute_translation_regime(vcpu, op) == TR_EL20 || > !(vcpu_read_sys_reg(vcpu, HCR_EL2) & (HCR_VM | HCR_DC))) > return; Ah, same solution, just way better written! Thanks, M. -- Without deviation from the norm, progress is not possible.