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 22213C282C8 for ; Mon, 28 Jan 2019 14:35:31 +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 D9F9C21738 for ; Mon, 28 Jan 2019 14:35:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Ho5yMAsr" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D9F9C21738 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=Nko+KwavpVfsPdsXK2FXh+Ow+of4v2mVp0/uI01K1T4=; b=Ho5yMAsriNtZqa trC4RxSCkYuqaJSzyHESJ2bYN5ibKSS7pYPuq4dLoq9fKuaHmyq8coeANXXcm06n9vGDBNybQdNVg hwCl6igDpb+YAL2mVdvaI2xOmiZTNAEF5e7pZo1IrrIxhn5/Mu3ir+DxE+mTcgrTjfcfjo8OHX2ja 3QnSoNUmd3rB/AOEzIz0dePtTXTqdhAAKO0txPYGKiCeik+n0bMY8ljYKCapLpMEZxStpbNmoXzzV 1xl1/3ZPrWXRRjJMhjeaW9F7+lfuMOviWWTA3WaQzfAamm1+NkKVOAff7NkvZLQ2C3l8TmcLztrNh uNnpGM1q9Ao51S09Hl6A==; 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 1go80V-0004B5-EI; Mon, 28 Jan 2019 14:35:27 +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 1go80R-0004Al-Qk for linux-arm-kernel@lists.infradead.org; Mon, 28 Jan 2019 14:35:25 +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 3232180D; Mon, 28 Jan 2019 06:35:23 -0800 (PST) Received: from [10.1.197.45] (e112298-lin.cambridge.arm.com [10.1.197.45]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 866533F589; Mon, 28 Jan 2019 06:35:21 -0800 (PST) Subject: Re: [PATCH v5 4/5] arm64/kvm: add a userspace option to enable pointer authentication To: Amit Daniel Kachhap , linux-arm-kernel@lists.infradead.org References: <1548658727-14271-1-git-send-email-amit.kachhap@arm.com> <1548658727-14271-5-git-send-email-amit.kachhap@arm.com> From: Julien Thierry Message-ID: Date: Mon, 28 Jan 2019 14:35:19 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <1548658727-14271-5-git-send-email-amit.kachhap@arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190128_063523_916698_E70376E5 X-CRM114-Status: GOOD ( 27.58 ) 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: Marc Zyngier , Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, Kristina Martsenko , Dave Martin , Ramana Radhakrishnan , kvmarm@lists.cs.columbia.edu 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 28/01/2019 06:58, 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. > I had a bit of trouble parsing this last sentence. I'd suggest rewording it as "No additional register is created for the SET/GET_ONE_REG API, instead just pass this parameter as a flag". > Signed-off-by: Amit Daniel Kachhap > Cc: Mark Rutland > Cc: Marc Zyngier > Cc: Christoffer Dall > Cc: Kristina Martsenko > Cc: kvmarm@lists.cs.columbia.edu > Cc: Ramana Radhakrishnan > Cc: Will Deacon > --- > Documentation/arm64/pointer-authentication.txt | 9 +++++---- > Documentation/virtual/kvm/api.txt | 4 ++++ > arch/arm/include/asm/kvm_host.h | 4 ++++ > arch/arm64/include/asm/kvm_host.h | 7 ++++--- > arch/arm64/include/uapi/asm/kvm.h | 1 + > arch/arm64/kvm/handle_exit.c | 3 ++- > arch/arm64/kvm/hyp/ptrauth-sr.c | 13 +++++++++++++ > arch/arm64/kvm/reset.c | 3 +++ > include/uapi/linux/kvm.h | 1 + > 9 files changed, 37 insertions(+), 8 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 or treats them as undefined if not set. I'd suggest "then the KVM guest allows the execution of pointer authentication instructions. Otherwise, KVM treats these instructions as undefined." > > > 4.83 KVM_ARM_PREFERRED_TARGET > diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h > index b200c14..b6950df 100644 > --- a/arch/arm/include/asm/kvm_host.h > +++ b/arch/arm/include/asm/kvm_host.h > @@ -346,6 +346,10 @@ static inline int kvm_arm_have_ssbd(void) > static inline void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu) {} > static inline void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu) {} > static inline void kvm_arm_vcpu_ptrauth_reset(struct kvm_vcpu *vcpu) {} > +static inline bool kvm_arm_vcpu_ptrauth_allowed(struct kvm_vcpu *vcpu) > +{ > + return false; > +} > > #define __KVM_HAVE_ARCH_VM_ALLOC > struct kvm *kvm_arch_alloc_vm(void); > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index c798d0c..4a6ec40 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -43,7 +43,7 @@ > > #define KVM_MAX_VCPUS VGIC_V3_MAX_CPUS > > -#define KVM_VCPU_MAX_FEATURES 4 > +#define KVM_VCPU_MAX_FEATURES 5 > > #define KVM_REQ_SLEEP \ > KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) > @@ -453,14 +453,15 @@ static inline bool kvm_arch_requires_vhe(void) > > void kvm_arm_vcpu_ptrauth_enable(struct kvm_vcpu *vcpu); > void kvm_arm_vcpu_ptrauth_disable(struct kvm_vcpu *vcpu); > +bool kvm_arm_vcpu_ptrauth_allowed(struct kvm_vcpu *vcpu); > > static inline void kvm_arm_vcpu_ptrauth_reset(struct kvm_vcpu *vcpu) > { > /* Disable ptrauth and use it in a lazy context via traps */ > - if (has_vhe() && kvm_supports_ptrauth()) > + if (has_vhe() && kvm_supports_ptrauth() > + && kvm_arm_vcpu_ptrauth_allowed(vcpu)) > kvm_arm_vcpu_ptrauth_disable(vcpu); > } > - > void kvm_arm_vcpu_ptrauth_trap(struct kvm_vcpu *vcpu); > > static inline void kvm_arch_hardware_unsetup(void) {} > 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 */ > > struct kvm_vcpu_init { > __u32 target; > diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c > index 5b980e7..c0e5dcd 100644 > --- a/arch/arm64/kvm/handle_exit.c > +++ b/arch/arm64/kvm/handle_exit.c > @@ -179,7 +179,8 @@ static int handle_sve(struct kvm_vcpu *vcpu, struct kvm_run *run) > */ > void kvm_arm_vcpu_ptrauth_trap(struct kvm_vcpu *vcpu) > { > - if (has_vhe() && kvm_supports_ptrauth()) > + if (has_vhe() && kvm_supports_ptrauth() > + && kvm_arm_vcpu_ptrauth_allowed(vcpu)) > kvm_arm_vcpu_ptrauth_enable(vcpu); > else > kvm_inject_undefined(vcpu); > diff --git a/arch/arm64/kvm/hyp/ptrauth-sr.c b/arch/arm64/kvm/hyp/ptrauth-sr.c > index 0576c01..369624f 100644 > --- a/arch/arm64/kvm/hyp/ptrauth-sr.c > +++ b/arch/arm64/kvm/hyp/ptrauth-sr.c > @@ -42,3 +42,16 @@ void __no_ptrauth __hyp_text __ptrauth_switch_to_host(struct kvm_vcpu *vcpu, > ptrauth_keys_store((struct ptrauth_keys *) &guest_ctxt->sys_regs[APIAKEYLO_EL1]); > ptrauth_keys_switch((struct ptrauth_keys *) &host_ctxt->sys_regs[APIAKEYLO_EL1]); > } > + > +/** > + * kvm_arm_vcpu_ptrauth_allowed - checks if ptrauth feature is present in vcpu > + * > + * @vcpu: The VCPU pointer > + * > + * This function will be used to enable/disable ptrauth in guest as configured > + * by the KVM userspace API. > + */ > +bool kvm_arm_vcpu_ptrauth_allowed(struct kvm_vcpu *vcpu) Nit: I find the "allowed" a bit strange. Maybe something like "kvm_arm_vcpu_has_ptrauth()" ? > +{ > + return test_bit(KVM_ARM_VCPU_PTRAUTH, vcpu->arch.features); > +} > diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c > index b72a3dd..987e0c3c 100644 > --- a/arch/arm64/kvm/reset.c > +++ b/arch/arm64/kvm/reset.c > @@ -91,6 +91,9 @@ int kvm_arch_vm_ioctl_check_extension(struct kvm *kvm, long ext) > case KVM_CAP_ARM_VM_IPA_SIZE: > r = kvm_ipa_limit; > break; > + case KVM_CAP_ARM_PTRAUTH: > + r = kvm_supports_ptrauth(); Even if we don't have VHE? Cheers, -- Julien Thierry _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel