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=-12.0 required=3.0 tests=BAYES_00,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 646BFC433DB for ; Mon, 11 Jan 2021 13:29:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3EFC821919 for ; Mon, 11 Jan 2021 13:29:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733111AbhAKN3M (ORCPT ); Mon, 11 Jan 2021 08:29:12 -0500 Received: from mail.kernel.org ([198.145.29.99]:41728 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732732AbhAKN3C (ORCPT ); Mon, 11 Jan 2021 08:29:02 -0500 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 97B0021919; Mon, 11 Jan 2021 13:28:21 +0000 (UTC) Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1kyxF5-006gPD-Gd; Mon, 11 Jan 2021 13:28:19 +0000 From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org Cc: Catalin Marinas , Will Deacon , Mark Rutland , David Brazdil , Alexandru Elisei , Ard Biesheuvel , Jing Zhang , Ajay Patil , Prasad Sodagudi , Srinivas Ramana , James Morse , Julien Thierry , Suzuki K Poulose , kernel-team@android.com Subject: [PATCH v3 00/21] arm64: Early CPU feature override, and applications to VHE, BTI and PAuth Date: Mon, 11 Jan 2021 13:27:50 +0000 Message-Id: <20210111132811.2455113-1-maz@kernel.org> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, dbrazdil@google.com, alexandru.elisei@arm.com, ardb@kernel.org, jingzhangos@google.com, pajay@qti.qualcomm.com, psodagud@codeaurora.org, sramana@codeaurora.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.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 It recently came to light that there is a need to be able to override some CPU features very early on, before the kernel is fully up and running. The reasons for this range from specific feature support (such as using Protected KVM on VHE HW, which is the main motivation for this work) to errata workaround (a feature is broken on a CPU and needs to be turned off, or rather not enabled). This series tries to offer a limited framework for this kind of problems, by allowing a set of options to be passed on the command-line and altering the feature set that the cpufeature subsystem exposes to the rest of the kernel. Note that this doesn't change anything for code that directly uses the CPU ID registers. The series completely changes the way a VHE-capable system boots, by *always* booting non-VHE first, and then upgrading to VHE when deemed capable. Although it sounds scary, this is actually simple to implement (and I wish I had done that five years ago). The "upgrade to VHE" path is then conditioned on the VHE feature not being disabled from the command-line. Said command-line parsing borrows a lot from the kaslr code, and subsequently allows the "nokaslr" option to be moved to the new infrastructure (though it all looks a bit... odd). Further patches now add support for disabling BTI and PAuth, the latter being based on an initial series by Srinivas Ramana[0]. This has been tested on multiple VHE and non-VHE systems. * From v2 [2]: - Simplify the VHE_RESTART stub - Fixed a number of spelling mistakes, and hopefully introduced a few more - Override features in __read_sysreg_by_encoding() - Allow both BTI and PAuth to be overridden on the command line - Rebased on -rc3 * From v1 [1]: - Fix SPE init on VHE when EL2 doesn't own SPE - Fix re-init when KASLR is used - Handle the resume path - Rebased to 5.11-rc2 [0] https://lore.kernel.org/r/1610152163-16554-1-git-send-email-sramana@codeaurora.org [1] https://lore.kernel.org/r/20201228104958.1848833-1-maz@kernel.org [2] https://lore.kernel.org/r/20210104135011.2063104-1-maz@kernel.org Marc Zyngier (20): arm64: Fix labels in el2_setup macros arm64: Fix outdated TCR setup comment arm64: Turn the MMU-on sequence into a macro arm64: Provide an 'upgrade to VHE' stub hypercall arm64: Initialise as nVHE before switching to VHE arm64: Move VHE-specific SPE setup to mutate_to_vhe() arm64: Simplify init_el2_state to be non-VHE only arm64: Move SCTLR_EL1 initialisation to EL-agnostic code arm64: cpufeature: Add global feature override facility arm64: cpufeature: Use IDreg override in __read_sysreg_by_encoding() arm64: Extract early FDT mapping from kaslr_early_init() arm64: cpufeature: Add an early command-line cpufeature override facility arm64: Allow ID_AA64MMFR1_EL1.VH to be overridden from the command line arm64: Honor VHE being disabled from the command-line arm64: Add an aliasing facility for the idreg override arm64: Make kvm-arm.mode={nvhe,protected} an alias of id_aa64mmfr1.vh=0 KVM: arm64: Document HVC_VHE_RESTART stub hypercall arm64: Move "nokaslr" over to the early cpufeature infrastructure arm64: cpufeatures: Allow disabling of BTI from the command-line arm64: cpufeatures: Allow disabling of Pointer Auth from the command-line Srinivas Ramana (1): arm64: Defer enabling pointer authentication on boot core .../admin-guide/kernel-parameters.txt | 9 + Documentation/virt/kvm/arm/hyp-abi.rst | 9 + arch/arm64/include/asm/assembler.h | 17 ++ arch/arm64/include/asm/cpufeature.h | 10 + arch/arm64/include/asm/el2_setup.h | 60 ++---- arch/arm64/include/asm/pointer_auth.h | 10 + arch/arm64/include/asm/setup.h | 11 + arch/arm64/include/asm/stackprotector.h | 1 + arch/arm64/include/asm/virt.h | 7 +- arch/arm64/kernel/Makefile | 2 +- arch/arm64/kernel/cpufeature.c | 57 ++++- arch/arm64/kernel/head.S | 75 ++----- arch/arm64/kernel/hyp-stub.S | 124 ++++++++++- arch/arm64/kernel/idreg-override.c | 199 ++++++++++++++++++ arch/arm64/kernel/kaslr.c | 44 +--- arch/arm64/kernel/setup.c | 15 ++ arch/arm64/kernel/sleep.S | 1 + arch/arm64/kvm/arm.c | 3 + arch/arm64/kvm/hyp/nvhe/hyp-init.S | 2 +- arch/arm64/mm/mmu.c | 2 +- arch/arm64/mm/proc.S | 16 +- 21 files changed, 505 insertions(+), 169 deletions(-) create mode 100644 arch/arm64/include/asm/setup.h create mode 100644 arch/arm64/kernel/idreg-override.c -- 2.29.2