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 X-Spam-Level: X-Spam-Status: No, score=-14.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CFD29C07E9D for ; Mon, 19 Jul 2021 12:55:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B5F26610A5 for ; Mon, 19 Jul 2021 12:55:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237092AbhGSMPK (ORCPT ); Mon, 19 Jul 2021 08:15:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:45522 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231282AbhGSMPF (ORCPT ); Mon, 19 Jul 2021 08:15:05 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 458F56100C; Mon, 19 Jul 2021 12:55:45 +0000 (UTC) Received: from sofa.misterjones.org ([185.219.108.64] helo=why.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 1m5SoB-00EDHx-4s; Mon, 19 Jul 2021 13:55:43 +0100 Date: Mon, 19 Jul 2021 13:55:29 +0100 Message-ID: <87im16jwe6.wl-maz@kernel.org> From: Marc Zyngier To: Quentin Perret Cc: james.morse@arm.com, alexandru.elisei@arm.com, suzuki.poulose@arm.com, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, ardb@kernel.org, qwandor@google.com, tabba@google.com, dbrazdil@google.com, kernel-team@android.com Subject: Re: [PATCH 05/14] KVM: arm64: Don't overwrite ignored bits with owner id In-Reply-To: <20210719104735.3681732-6-qperret@google.com> References: <20210719104735.3681732-1-qperret@google.com> <20210719104735.3681732-6-qperret@google.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/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: qperret@google.com, james.morse@arm.com, alexandru.elisei@arm.com, suzuki.poulose@arm.com, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, ardb@kernel.org, qwandor@google.com, tabba@google.com, dbrazdil@google.com, kernel-team@android.com 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: linux-kernel@vger.kernel.org On Mon, 19 Jul 2021 11:47:26 +0100, Quentin Perret wrote: > > The nVHE protected mode uses invalid mappings in the host stage-2 > page-table to track the owner of each page in the system. In order to > allow the usage of ignored bits (a.k.a. software bits) in these > mappings, move the owner encoding away from the top bits. But that's exactly what the current situation is allowing: the use of the SW bits. I am guessing that what you really mean is that you want to *preserve* the SW bits from an existing mapping and use other bits when the mapping is invalid? Thanks, M. > > Signed-off-by: Quentin Perret > --- > arch/arm64/kvm/hyp/pgtable.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c > index a60653cbd8e5..a0ac8c2bc174 100644 > --- a/arch/arm64/kvm/hyp/pgtable.c > +++ b/arch/arm64/kvm/hyp/pgtable.c > @@ -50,7 +50,7 @@ > KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | \ > KVM_PTE_LEAF_ATTR_HI_S2_XN) > > -#define KVM_INVALID_PTE_OWNER_MASK GENMASK(63, 56) > +#define KVM_INVALID_PTE_OWNER_MASK GENMASK(9, 2) > #define KVM_MAX_OWNER_ID 1 > > struct kvm_pgtable_walk_data { > -- > 2.32.0.402.g57bb445576-goog > > -- Without deviation from the norm, progress is not possible.