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=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 9A87FC43381 for ; Thu, 28 Feb 2019 09:25:18 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 674962184A for ; Thu, 28 Feb 2019 09:25:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="o/JCpjwL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 674962184A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=HslDwCXje7jME8e5gsIKgIYdYmgty6dOnuYCQy9LprU=; b=o/JCpjwLsyHm8v9T8K/2KTUpv u9MF7py3/WMqHup9HjSyxZ8GMpPo0FTi51q7Triv8BhMsSZzn+XFVWw7P43Jzu8ETijQXdjDfBqJZ bDagOzdY/1O7sVtXEceO8yKHsAck6vRTONemdL0w2AD0+u4vFA8tGtwrzUFv9gMObHYxs8A/cp50y K2jo+2IMpvGu8jRc24cc7yUx27qZbAFN5t+SdhsJ+DPGE7UQfDVksTeTpqYEJuR2pu8u2JZj4PACQ TFy/6W4nTTmO8Gz8LcM1eZV3jcOBRthloI1ImiytLN1jTV0bZhF0xAWDKbWuM4+5ktS8CljAj2ZNk hwwIYb0kQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gzHwH-0008T3-0w; Thu, 28 Feb 2019 09:25:13 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gzHwE-0008SJ-8Z for linux-arm-kernel@lists.infradead.org; Thu, 28 Feb 2019 09:25:11 +0000 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 25AFDEBD; Thu, 28 Feb 2019 01:25:08 -0800 (PST) Received: from [10.162.0.144] (a075553-lin.blr.arm.com [10.162.0.144]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4F2663F738; Thu, 28 Feb 2019 01:25:04 -0800 (PST) Subject: Re: [PATCH v6 4/6] arm64/kvm: add a userspace option to enable pointer authentication To: Mark Rutland References: <1550568271-5319-1-git-send-email-amit.kachhap@arm.com> <1550568271-5319-5-git-send-email-amit.kachhap@arm.com> <20190221123416.GD33673@lakrids.cambridge.arm.com> From: Amit Daniel Kachhap Message-ID: Date: Thu, 28 Feb 2019 14:55:02 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190221123416.GD33673@lakrids.cambridge.arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190228_012510_315354_7401E6D6 X-CRM114-Status: GOOD ( 20.61 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andrew Jones , linux-kernel@vger.kernel.org, Julien Thierry , Marc Zyngier , Catalin Marinas , Will Deacon , Christoffer Dall , Kristina Martsenko , kvmarm@lists.cs.columbia.edu, James Morse , Ramana Radhakrishnan , Dave Martin , linux-arm-kernel@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, On 2/21/19 6:04 PM, Mark Rutland wrote: > On Tue, Feb 19, 2019 at 02:54:29PM +0530, Amit Daniel Kachhap wrote: >> This feature will allow the KVM guest to allow the handling of >> pointer authentication instructions or to treat them as undefined >> if not set. It uses the existing vcpu API KVM_ARM_VCPU_INIT to >> supply this parameter instead of creating a new API. >> >> A new register is not created to pass this parameter via >> SET/GET_ONE_REG interface as just a flag (KVM_ARM_VCPU_PTRAUTH) >> supplied is enough to enable this feature. >> >> Signed-off-by: Amit Daniel Kachhap >> Cc: Mark Rutland >> Cc: Marc Zyngier >> Cc: Christoffer Dall >> Cc: kvmarm@lists.cs.columbia.edu >> --- >> Documentation/arm64/pointer-authentication.txt | 9 +++++---- >> Documentation/virtual/kvm/api.txt | 4 ++++ >> arch/arm64/include/asm/kvm_host.h | 3 ++- >> arch/arm64/include/uapi/asm/kvm.h | 1 + >> arch/arm64/kvm/handle_exit.c | 2 +- >> arch/arm64/kvm/hyp/ptrauth-sr.c | 16 +++++++++++++++- >> arch/arm64/kvm/reset.c | 3 +++ >> arch/arm64/kvm/sys_regs.c | 26 +++++++++++++------------- >> include/uapi/linux/kvm.h | 1 + >> 9 files changed, 45 insertions(+), 20 deletions(-) >> >> diff --git a/Documentation/arm64/pointer-authentication.txt b/Documentation/arm64/pointer-authentication.txt >> index a25cd21..0529a7d 100644 >> --- a/Documentation/arm64/pointer-authentication.txt >> +++ b/Documentation/arm64/pointer-authentication.txt >> @@ -82,7 +82,8 @@ pointers). >> Virtualization >> -------------- >> >> -Pointer authentication is not currently supported in KVM guests. KVM >> -will mask the feature bits from ID_AA64ISAR1_EL1, and attempted use of >> -the feature will result in an UNDEFINED exception being injected into >> -the guest. >> +Pointer authentication is enabled in KVM guest when virtual machine is >> +created by passing a flag (KVM_ARM_VCPU_PTRAUTH) requesting this feature >> +to be enabled. Without this flag, pointer authentication is not enabled >> +in KVM guests and attempted use of the feature will result in an UNDEFINED >> +exception being injected into the guest. >> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt >> index 356156f..1e646fb 100644 >> --- a/Documentation/virtual/kvm/api.txt >> +++ b/Documentation/virtual/kvm/api.txt >> @@ -2642,6 +2642,10 @@ Possible features: >> Depends on KVM_CAP_ARM_PSCI_0_2. >> - KVM_ARM_VCPU_PMU_V3: Emulate PMUv3 for the CPU. >> Depends on KVM_CAP_ARM_PMU_V3. >> + - KVM_ARM_VCPU_PTRAUTH: Emulate Pointer authentication for the CPU. >> + Depends on KVM_CAP_ARM_PTRAUTH and only on arm64 architecture. If >> + set, then the KVM guest allows the execution of pointer authentication >> + instructions. Otherwise, KVM treats these instructions as undefined. > > I think that we should have separate flags for address auth and generic > auth, to match the ID register split. > > For now, we can have KVM only support the case where both are set, but > it gives us freedom to support either in isolation if we have to in > future, without an ABI break. yes agree with you about having two address and generic ptrauth flags. Will add in next iteration. Thanks, Amit D > > Thanks, > Mark. > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel