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 4F54FC10DC1 for ; Mon, 4 Dec 2023 11:04:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Subject:Cc:To:From:Message-ID:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=J99IZ7MRHT6krurwzPSwkwB7NdOH4xCTJBVPi0e5rYQ=; b=BoTrWZ9HhGc6fD vtLVubG0PQ3k6WiduMgIIh66hN1RePCoOXAJ0QaBdr9BQLw9zjJdl80LGe286Rdf2EUoC1MCA1Rqu V1+Y38aPXth5tP6Qax0sKh240d1TVhDHX5Z1kjyAoH3oHwawvI87MYB0cTTFvOO4887OEk15WRDs2 PD99eBEAru5JVMIJDw3GqI7NbYFd0TvHZZltZ2+8EnB2SUnbbynl4Jo34mpgQkC7yYVJRWpISY+nj abHS0q+/zCxk8DR655eHjPUK/+v4z5EP0QglIgNgJY8ZaI6iaTMUagNcbLiJg3NiFaGzx0Up8g2ba cgcH9GBtKaaC3mbRJWBw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rA6jg-003cXq-0a; Mon, 04 Dec 2023 11:03:36 +0000 Received: from sin.source.kernel.org ([145.40.73.55]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1rA6jc-003cVB-0a for linux-arm-kernel@lists.infradead.org; Mon, 04 Dec 2023 11:03:34 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id A4C5ACE0F22; Mon, 4 Dec 2023 11:03:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C2FDCC433C7; Mon, 4 Dec 2023 11:03:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1701687808; bh=td2FHNFbaEBhn6/pKvODA/OD7GSweig2jmUFrnTj5ag=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=r7zJ1vDrsKNETcUBXXgqaZq6Wk03L1ZzHpvEGkz45riz5nQZDIo72NUTT4HuGntNq qX2pr4CDP/8s4bgsQoMq4tozF/fmyCc9PcQFTWg8qOQaFuYlSFogTROx3mSkFluwUr 5iF/pvd1gsO1yM25oy1txVw6llgnbmNecrEAVQYV9k5FsGTdZBpwC/cM55E5/WgI6y ghEBkvTEPbGSddIoNGtHhp9fsLL/gepQTyGFXEaZxrA4+mbXYZhsTTT/cRARv1pFYR Pre5QK1QcG8Osh9+gpDvHtwA12ZK69rJh15eFjEcEhChLi10Ua+NQ+BKcmoteS7s54 kN08CJrkDgEWQ== 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 1rA6jV-001CFD-VG; Mon, 04 Dec 2023 11:03:26 +0000 Date: Mon, 04 Dec 2023 11:03:24 +0000 Message-ID: <86jzpub56r.wl-maz@kernel.org> From: Marc Zyngier To: Joey Gouly Cc: linux-arm-kernel@lists.infradead.org, akpm@linux-foundation.org, aneesh.kumar@linux.ibm.com, broonie@kernel.org, catalin.marinas@arm.com, dave.hansen@linux.intel.com, oliver.upton@linux.dev, shuah@kernel.org, will@kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, James Morse , Suzuki K Poulose , Zenghui Yu Subject: Re: [PATCH v3 00/25] Permission Overlay Extension In-Reply-To: <20231124163510.1835740-1-joey.gouly@arm.com> References: <20231124163510.1835740-1-joey.gouly@arm.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/29.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: joey.gouly@arm.com, linux-arm-kernel@lists.infradead.org, akpm@linux-foundation.org, aneesh.kumar@linux.ibm.com, broonie@kernel.org, catalin.marinas@arm.com, dave.hansen@linux.intel.com, oliver.upton@linux.dev, shuah@kernel.org, will@kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com 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-20231204_030332_695561_287C4EB4 X-CRM114-Status: GOOD ( 16.65 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Joey, On Fri, 24 Nov 2023 16:34:45 +0000, Joey Gouly wrote: > > Hello everyone, > > This series implements the Permission Overlay Extension introduced in 2022 > VMSA enhancements [1]. It is based on v6.7-rc2. > > Changes since v2[2]: > # Added ptrace support and selftest > # Add missing POR_EL0 initialisation in fork/clone > # Rebase onto v6.7-rc2 > # Add r-bs > > The Permission Overlay Extension allows to constrain permissions on memory > regions. This can be used from userspace (EL0) without a system call or TLB > invalidation. I have given this series a few more thoughts, and came to the conclusion that is it still incomplete on the KVM front: * FEAT_S1POE often comes together with FEAT_S2POE. For obvious reasons, we cannot afford to let the guest play with S2POR_EL1, nor do we want to advertise FEAT_S2POE to the guest. You will need to add some additional FGT for this, and mask out FEAT_S2POE from the guest's view of the ID registers. * letting the guest play with POE comes with some interesting strings attached: a guest that has started on a POE-enabled host cannot be migrated to one that doesn't have POE. which means that the POE registers should only be visible to the host userspace if enabled in the guest's ID registers, and thus only context-switched in these conditions. They should otherwise UNDEF. Thanks, M. -- Without deviation from the norm, progress is not possible. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel