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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 C461AC43381 for ; Tue, 26 Mar 2019 18:01:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8FFD12082F for ; Tue, 26 Mar 2019 18:01:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732367AbfCZSBt (ORCPT ); Tue, 26 Mar 2019 14:01:49 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:41730 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732069AbfCZSBs (ORCPT ); Tue, 26 Mar 2019 14:01:48 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 685501596; Tue, 26 Mar 2019 11:01:48 -0700 (PDT) Received: from [10.1.197.21] (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CC9713F614; Tue, 26 Mar 2019 11:01:45 -0700 (PDT) Subject: Re: [PATCH v7 7/10] KVM: arm/arm64: context-switch ptrauth registers To: Amit Daniel Kachhap , linux-arm-kernel@lists.infradead.org Cc: Christoffer Dall , Marc Zyngier , Catalin Marinas , Will Deacon , Andrew Jones , Dave Martin , Ramana Radhakrishnan , kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, Mark Rutland , James Morse , Julien Thierry References: <1552984243-7689-1-git-send-email-amit.kachhap@arm.com> <1552984243-7689-8-git-send-email-amit.kachhap@arm.com> <64505666-8a1f-cf64-7067-4b2dd53b0b40@arm.com> From: Kristina Martsenko Message-ID: <949327ae-081c-0964-3315-ac2695243b5f@arm.com> Date: Tue, 26 Mar 2019 18:01:44 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 26/03/2019 04:03, Amit Daniel Kachhap wrote: > Hi, > > On 3/26/19 1:34 AM, Kristina Martsenko wrote: >> On 19/03/2019 08:30, Amit Daniel Kachhap wrote: >>> From: Mark Rutland >>> >>> When pointer authentication is supported, a guest may wish to use it. >>> This patch adds the necessary KVM infrastructure for this to work, with >>> a semi-lazy context switch of the pointer auth state. >> >> [...] >> >>> +    if (test_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, vcpu->arch.features) || >>> +        test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, vcpu->arch.features)) { >>> +        /* Verify that KVM startup matches the conditions for ptrauth */ >>> +        if (WARN_ON(!vcpu_has_ptrauth(vcpu))) >>> +            return -EINVAL; >>> +    } >> >> I think this now needs to have "goto out;" instead of "return -EINVAL;", >> since 5.1-rcX contains commit e761a927bc9a ("KVM: arm/arm64: Reset the >> VCPU without preemption and vcpu state loaded") which changed some of >> this code. > ok missed the changes for this commit. One more thing - I think the WARN_ON() here should be removed. Otherwise if panic_on_warn is set then userspace can panic the kernel. I think WARN_ON is only for internal kernel errors (see comment in include/asm-generic/bug.h). Thanks, Kristina