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=-4.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=no 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 1CFD5C433E0 for ; Thu, 4 Jun 2020 13:34:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E705D20823 for ; Thu, 4 Jun 2020 13:34:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591277646; bh=rcP0ID3sZv+j+DKkPTrcUriG90Uun00qknLwobPg9EU=; h=From:To:Cc:Subject:Date:List-ID:From; b=ut0JTnpAELeZFy7u2Ug7+/AIMp5n704HyXFbIe1qv2IiyLQ9XOYbmDZg90SXVjj7y wZswsc5Fy9x/k+dLVL0N/N2Gp4thv3fkgKbzM49KHBs0aZs9vR1L0mG/HhEG/kCrFH b3oyvMq/8ggCHHyNX+z573P2FBpqCNXDs5uTO2AA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728607AbgFDNeG (ORCPT ); Thu, 4 Jun 2020 09:34:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:36164 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728550AbgFDNeF (ORCPT ); Thu, 4 Jun 2020 09:34:05 -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 099E120772; Thu, 4 Jun 2020 13:34:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591277645; bh=rcP0ID3sZv+j+DKkPTrcUriG90Uun00qknLwobPg9EU=; h=From:To:Cc:Subject:Date:From; b=PNA+5znUqtVizpteIx5iiQH+oJlxiDqad2kOGfq9Qemb6XNvFMSy8+8BhCaCxVeYF DuC1RWChGU82A86yA3iGVXIOGL7Ke90uWaxbkMVFnsbCI86sf594bpQ2s6Wy1we3xu 1LTE4mL0vo8yyu7tdIuAujVsdbNWI+0X6xczLYIk= 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:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jgq0R-000G3O-GP; Thu, 04 Jun 2020 14:34:03 +0100 From: Marc Zyngier To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Cc: James Morse , Julien Thierry , Suzuki K Poulose , Will Deacon , Catalin Marinas , Mark Rutland , kernel-team@android.com Subject: [PATCH 0/3] kvm: arm64: Pointer Authentication handling fixes Date: Thu, 4 Jun 2020 14:33:51 +0100 Message-Id: <20200604133354.1279412-1-maz@kernel.org> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, will@kernel.org, catalin.marinas@arm.com, mark.rutland@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 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org I recently discovered that the Pointer Authentication (PtrAuth) handling code in KVM is busted, and has been for a while. The main issue is that the we save the host's keys from a preemptible context. Things will go wrong at some point. In order to address this, the first patch move the saving of the host's keys to vcpu_load(). It is done eagerly, which is a bore, but is at least safe. This is definitely stable material. The following two patches are adding an optimisation and a fix for a corner case: we handle key saving and HCR massaging as a fixup, much like the FPSIMD code. This subsequently allows us to deal with the ugly case of a guest enabling PtrAuth despite it not being advertised, resulting in PAC instructions UNDEF'ing while they should be NOPs. This has been very lightly tested on a model. Marc Zyngier (3): KVM: arm64: Save the host's PtrAuth keys in non-preemptible context KVM: arm64: Handle PtrAuth traps early KVM: arm64: Enforce PtrAuth being disabled if not advertized arch/arm64/include/asm/kvm_emulate.h | 6 --- arch/arm64/kvm/arm.c | 3 +- arch/arm64/kvm/handle_exit.c | 38 --------------- arch/arm64/kvm/hyp/switch.c | 73 ++++++++++++++++++++++++++++ arch/arm64/kvm/sys_regs.c | 13 ++--- 5 files changed, 80 insertions(+), 53 deletions(-) -- 2.26.2