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=-3.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS 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 9B9D1C43381 for ; Tue, 26 Feb 2019 18:33:29 +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 6C9272173C for ; Tue, 26 Feb 2019 18:33:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="uigRLhBi" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6C9272173C 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-Transfer-Encoding:Content-Type: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=veAI5eYa4BTAwzWftFrr5kxHoXwaFrhMvMmXfHh0e1Y=; b=uigRLhBi2czBzw uyYb3VcvkAKfnE3wTLQ/LCJSRahSRNz75vH32IPoiO78c1w1r28cMZmnpVqxT+paoTLbl2QiSEiSt HbKB57k24g8jUG6N3hRBN2Qulg55aePSEsiAQBAfk49+tERGanpwg5c1r1Bb+ZpjxbmB6WqZIgoww SVZSLpUojXRf3DnF2ayan2u0dwfYC6L+gTLShKwDptvc06Of69Rn9frfyUJUgMQvksHF7+axxRdEL MsNPw1E3ebXf9hC7e2sDhU7bUoZbmDbIYrO5fsKHrCckevAdPvhwGM83qnrsbTttk91RrztmZ1yZY dO6tZPmFa7V6LmhbsVkw==; 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 1gyhXf-00057X-Lw; Tue, 26 Feb 2019 18:33:23 +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 1gyhXc-000575-GL for linux-arm-kernel@lists.infradead.org; Tue, 26 Feb 2019 18:33:22 +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 3D29380D; Tue, 26 Feb 2019 10:33:19 -0800 (PST) Received: from [10.1.196.105] (eglon.cambridge.arm.com [10.1.196.105]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 024B73F738; Tue, 26 Feb 2019 10:33:16 -0800 (PST) Subject: Re: [PATCH v6 4/6] arm64/kvm: add a userspace option to enable pointer authentication To: Amit Daniel Kachhap , linux-arm-kernel@lists.infradead.org References: <1550568271-5319-1-git-send-email-amit.kachhap@arm.com> <1550568271-5319-5-git-send-email-amit.kachhap@arm.com> From: James Morse Message-ID: Date: Tue, 26 Feb 2019 18:33:15 +0000 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <1550568271-5319-5-git-send-email-amit.kachhap@arm.com> Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190226_103320_557298_A680DF97 X-CRM114-Status: GOOD ( 24.12 ) 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: Mark Rutland , Andrew Jones , Julien Thierry , Marc Zyngier , Catalin Marinas , Will Deacon , Christoffer Dall , Kristina Martsenko , kvmarm@lists.cs.columbia.edu, Ramana Radhakrishnan , Dave Martin , linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Amit, On 19/02/2019 09:24, 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. and an attempt to restore the id register with the other version would fail. > 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) (This is still mixing VM and VCPU) > + requesting this feature to be enabled. .. on each vcpu? > +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. 'guests' here suggests its a VM property. If you set it on some VCPU but not others KVM will generate undefs instead of enabling the feature. (which is the right thing to do) I think it needs to be clear this is a per-vcpu property. > diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h > index 97c3478..5f82ca1 100644 > --- a/arch/arm64/include/uapi/asm/kvm.h > +++ b/arch/arm64/include/uapi/asm/kvm.h > @@ -102,6 +102,7 @@ struct kvm_regs { > #define KVM_ARM_VCPU_EL1_32BIT 1 /* CPU running a 32bit VM */ > #define KVM_ARM_VCPU_PSCI_0_2 2 /* CPU uses PSCI v0.2 */ > #define KVM_ARM_VCPU_PMU_V3 3 /* Support guest PMUv3 */ > +#define KVM_ARM_VCPU_PTRAUTH 4 /* VCPU uses address authentication */ Just address authentication? I agree with Mark we should have two bits to match what gets exposed to EL0. One would then be address, the other generic. > diff --git a/arch/arm64/kvm/hyp/ptrauth-sr.c b/arch/arm64/kvm/hyp/ptrauth-sr.c > index 528ee6e..6846a23 100644 > --- a/arch/arm64/kvm/hyp/ptrauth-sr.c > +++ b/arch/arm64/kvm/hyp/ptrauth-sr.c > @@ -93,9 +93,23 @@ void kvm_arm_vcpu_ptrauth_reset(struct kvm_vcpu *vcpu) > +/** > + * kvm_arm_vcpu_ptrauth_allowed - checks if ptrauth feature is allowed by user > + * > + * @vcpu: The VCPU pointer > + * > + * This function will be used to check userspace option to have ptrauth or not > + * in the guest kernel. > + */ > +bool kvm_arm_vcpu_ptrauth_allowed(const struct kvm_vcpu *vcpu) > +{ > + return kvm_supports_ptrauth() && > + test_bit(KVM_ARM_VCPU_PTRAUTH, vcpu->arch.features); > +} This isn't used from world-switch, could it be moved to guest.c? > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c > index 12529df..f7bcc60 100644 > --- a/arch/arm64/kvm/sys_regs.c > +++ b/arch/arm64/kvm/sys_regs.c > @@ -1055,7 +1055,7 @@ static bool access_cntp_cval(struct kvm_vcpu *vcpu, > } > > /* Read a sanitised cpufeature ID register by sys_reg_desc */ > -static u64 read_id_reg(struct sys_reg_desc const *r, bool raz) > +static u64 read_id_reg(struct kvm_vcpu *vcpu, struct sys_reg_desc const *r, bool raz) (It might be easier on the reviewer to move these mechanical changes to an earlier patch) Looks good, Thanks, James _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel