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 A90C6C19F2D for ; Tue, 9 Aug 2022 16:49:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244907AbiHIQti (ORCPT ); Tue, 9 Aug 2022 12:49:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33686 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243303AbiHIQte (ORCPT ); Tue, 9 Aug 2022 12:49:34 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 236D422528 for ; Tue, 9 Aug 2022 09:49:34 -0700 (PDT) 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 ams.source.kernel.org (Postfix) with ESMTPS id CF40DB81630 for ; Tue, 9 Aug 2022 16:49:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7762FC433D6; Tue, 9 Aug 2022 16:49:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660063771; bh=vmvrp06z/9E5ewruB9hgQbojabCvvAtIPWajE3UadeQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=t6I4JlIFvjmcpGC/JHRBo44PJ98DBijbD1LNg2Lxhc2dEh+ewO/2gHhfRBpY+mwef Ezn2QdoavHmJ2ClgL6pTJdVpyCemhpD0Uhjgsap7HhuXj1ufnvvBA5ruxmRNIiA5Cn axNCCEHzXR5h1rF/Cx76nvVV1TwuONnumgYLjOY8FIe3pBFjapwsaobMq8k8SM1/Eq m0vrO0qAATlK62IFwTuguL114cVlr5jN0IeiI/uIQxBNydTgVxvDMJqyxNVJmFdgdv MjjVHNC/Vx45kE/2mHI81wEjCJHcOW1jtDsF39ltDyxK7ugW1NRPBaYNPF3OA2Tcuq kaPWRPYTOxqXw== 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 4.95) (envelope-from ) id 1oLSQ5-001xDr-6g; Tue, 09 Aug 2022 17:49:29 +0100 Date: Tue, 09 Aug 2022 17:49:28 +0100 Message-ID: <87v8r1uztz.wl-maz@kernel.org> From: Marc Zyngier To: Evgenii Stepanov Cc: Catalin Marinas , Will Deacon , Peter Collingbourne , Vincenzo Frascino , Andrey Konovalov , Mark Brown , Linux ARM , LKML Subject: Re: [PATCH] mte: Follow arm64.nomte override in MMU setup. In-Reply-To: References: <20220805214734.1937451-1-eugenis@google.com> <875yj1x0k0.wl-maz@kernel.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: eugenis@google.com, catalin.marinas@arm.com, will@kernel.org, pcc@google.com, vincenzo.frascino@arm.com, andreyknvl@gmail.com, broonie@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.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: linux-kernel@vger.kernel.org On Tue, 09 Aug 2022 17:41:28 +0100, Evgenii Stepanov wrote: > > On Tue, Aug 9, 2022 at 1:50 AM Marc Zyngier wrote: > > How comes such memory is being used? How comes it is in the linear > > map? > > > > arm64.nomte is affecting the use of MTE feature on the platform. It > > doesn't guard the use of a MTE carve-out, and doesn't allow it to be > > used in any shape or form. > > > > To use this memory, you should remove the MTE configuration > > altogether, as you cannot infer what the CPU is doing with it. > > This can be used to enable MTE in TZ but not in the NS memory. In which case what is the tag memory doing in the linear map? Shouldn't it be marked as reserved, not mapped, and in general completely ignored by the NS OS? M. -- Without deviation from the norm, progress is not possible.