From patchwork Tue Dec 18 07:56:47 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amit Daniel Kachhap X-Patchwork-Id: 10734991 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 067126C2 for ; Tue, 18 Dec 2018 07:59:29 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E9F222A47B for ; Tue, 18 Dec 2018 07:59:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DDB352A486; Tue, 18 Dec 2018 07:59:28 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 3E63D2A47B for ; Tue, 18 Dec 2018 07:59:28 +0000 (UTC) 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:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=kyX/orDSyXdoRqmzIoXQp20n4HNsyhJym4nMqtovHoI=; b=H5ww+8nNJ7RHZ6xUdF2vi/G8Z6 lnoWqMknNKBcW2iVZCOkVcd+fI57+zhj0dC04av6/l7I5kgLgfmeZU2qQB40/cSzPMWZ85iLu/BBa yT83gwFVRNHFfoKcncE3IBfD0B39Qfh6Lw6X15yeoXdQMVOStrmRMDB4Y6Vu7lz3WtqXKjV6VrjYZ US434zb3k85NyARYgIcsa5BHpqdQ3XWyFNHYRsQ21krvrInxEBovKMfno4bygHaqWDiW2CdGx6JqS GLUJKRReMQcbJgZfuWJlI4BVX+dmN+OAGIXKLjq/IjUvfUva5Sau9mJQ8XDC9OcojqglaNNU1hY9D t5IF7jRQ==; 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 1gZAHj-00037X-GN; Tue, 18 Dec 2018 07:59:23 +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 1gZAFy-0001a5-Nx for linux-arm-kernel@lists.infradead.org; Tue, 18 Dec 2018 07:57:39 +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 1FF4480D; Mon, 17 Dec 2018 23:57:29 -0800 (PST) Received: from a75553-lin.blr.arm.com (a75553-lin.blr.arm.com [10.162.0.175]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 4ACCE3F575; Mon, 17 Dec 2018 23:57:25 -0800 (PST) From: Amit Daniel Kachhap To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v4 3/6] arm64/kvm: add a userspace option to enable pointer authentication Date: Tue, 18 Dec 2018 13:26:47 +0530 Message-Id: <1545119810-12182-4-git-send-email-amit.kachhap@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1545119810-12182-1-git-send-email-amit.kachhap@arm.com> References: <1545119810-12182-1-git-send-email-amit.kachhap@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181217_235734_832875_EF246462 X-CRM114-Status: GOOD ( 19.32 ) 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 , Marc Zyngier , Catalin Marinas , Will Deacon , Christoffer Dall , Kristina Martsenko , kvmarm@lists.cs.columbia.edu, Ramana Radhakrishnan , Amit Daniel Kachhap , Dave Martin , linux-kernel@vger.kernel.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP 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 select 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/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 | 2 +- arch/arm64/kvm/hyp/ptrauth-sr.c | 16 ++++++++++++++++ arch/arm64/kvm/reset.c | 3 +++ include/uapi/linux/kvm.h | 1 + 9 files changed, 39 insertions(+), 8 deletions(-) diff --git a/Documentation/arm64/pointer-authentication.txt b/Documentation/arm64/pointer-authentication.txt index 5baca42..8c0f338 100644 --- a/Documentation/arm64/pointer-authentication.txt +++ b/Documentation/arm64/pointer-authentication.txt @@ -87,7 +87,8 @@ used to get and set the keys for a thread. 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 cd209f7..e20583a 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -2634,6 +2634,10 @@ 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. 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 02d9bfc..62a85d9 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -352,6 +352,10 @@ 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_config(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 629712d..f853a95 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_check_sve_has_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_config(struct kvm_vcpu *vcpu) { /* Disable ptrauth and use it in a lazy context via traps */ - if (has_vhe() && system_supports_ptrauth()) + if (has_vhe() && system_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 5c47a8f47..3394028 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -180,7 +180,7 @@ static int handle_sve(struct kvm_vcpu *vcpu, struct kvm_run *run) */ void kvm_arm_vcpu_ptrauth_trap(struct kvm_vcpu *vcpu) { - if (system_supports_ptrauth()) + if (system_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 1bfaf74..03999bb 100644 --- a/arch/arm64/kvm/hyp/ptrauth-sr.c +++ b/arch/arm64/kvm/hyp/ptrauth-sr.c @@ -71,3 +71,19 @@ void __hyp_text __ptrauth_switch_to_host(struct kvm_vcpu *vcpu, __ptrauth_save_state(guest_ctxt); __ptrauth_restore_state(host_ctxt); } + +/** + * 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) +{ + if (test_bit(KVM_ARM_VCPU_PTRAUTH, vcpu->arch.features)) + return true; + else + return false; +} diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index b72a3dd..4656070 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 = system_supports_ptrauth(); + break; default: r = 0; } diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 2b7a652..fa48660 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -975,6 +975,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_HYPERV_ENLIGHTENED_VMCS 163 #define KVM_CAP_EXCEPTION_PAYLOAD 164 #define KVM_CAP_ARM_VM_IPA_SIZE 165 +#define KVM_CAP_ARM_PTRAUTH 166 #ifdef KVM_CAP_IRQ_ROUTING