Received: by 2002:a25:4158:0:0:0:0:0 with SMTP id o85csp3164765yba; Mon, 22 Apr 2019 21:46:53 -0700 (PDT) X-Google-Smtp-Source: APXvYqyYE7WIRXltxCVJlvSTXiCZyTZBaUy/VQo9JPLq2FNsdagGbd7UNEn3UfIh40Bq05kpNDc+ X-Received: by 2002:a17:902:29c9:: with SMTP id h67mr24181743plb.114.1555994813855; Mon, 22 Apr 2019 21:46:53 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1555994813; cv=none; d=google.com; s=arc-20160816; b=qYoX850m/+vVD6egFd7HVgfNlcZ+g1kZZs7Ds46IfMR+EWkLZVGEEfQfSkBuvB+BpP n3C5uHkZpVmkfd//82K1Fs7GN+Koxg+bsafacHxLLcL8rXPkHnfPxJeL5ZPetZprmJmP XhoyTf/pLMUD7t1r87SGd34sIL35dtRwBsaTSGge4wJWwKDQlWwONHKT8Y41mi2GTcsj 9rFUMRl+wXGQB8ObzVpCkNRHKscPiCSXYPhilD5kD8Xnt9vw/8hN2Ws/MnA7ho1HHDom 12kPmHl6D4F49aTQDZqIt0Ebht/S28TTo/k+qXZ+8QfPJtFS6fRfNN0fWGHnU3fhvGxD LjgQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from; bh=MFUF3U1RLLqleQKYz7PpCKoOxy1vWJ1Co/Foi0T1LTo=; b=wh8j4DHUnSYbzsDmW9Rq1gth1iXs8mRIMR8wVM4bBnqySov/1Oeu/4Ou1+xLDzF6Of QpEt5KwtPHN8fmGqaUK9AVNK8HIf/ld1dU9SYDi/dcOUXP4maxPjkGsu/yqWjIRpeUCs kWLUeRHRyZpEyiINRXNQ5qVqbIlUwEwTu3qHRLoGxZfu2/mt1uaPadRVmggoAApXzJ7o AKM/MNexd0oMm7l9r/sxB+6fN7xXGOa+IZsWESsHklboHscn0FVs/tkX7p03nuJtbHIr 12zwqxE2e256skbUkdcaVoyWKU+BwuubQhuGMvUiPl934/74XNnMSJKfk1Mp3NzkVavl h0cg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id y12si15467324plp.47.2019.04.22.21.46.38; Mon, 22 Apr 2019 21:46:53 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728183AbfDWEnI (ORCPT + 99 others); Tue, 23 Apr 2019 00:43:08 -0400 Received: from foss.arm.com ([217.140.101.70]:48914 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726135AbfDWEnH (ORCPT ); Tue, 23 Apr 2019 00:43:07 -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 4EE94EBD; Mon, 22 Apr 2019 21:43:07 -0700 (PDT) Received: from a075553-lin.blr.arm.com (a075553-lin.blr.arm.com [10.162.0.144]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 16BFE3F557; Mon, 22 Apr 2019 21:43:02 -0700 (PDT) From: Amit Daniel Kachhap To: 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, Kristina Martsenko , linux-kernel@vger.kernel.org, Amit Daniel Kachhap , Mark Rutland , James Morse , Julien Thierry Subject: [PATCH v10 3/5] KVM: arm64: Add userspace flag to enable pointer authentication Date: Tue, 23 Apr 2019 10:12:36 +0530 Message-Id: <1555994558-26349-4-git-send-email-amit.kachhap@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1555994558-26349-1-git-send-email-amit.kachhap@arm.com> References: <1555994558-26349-1-git-send-email-amit.kachhap@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Now that the building blocks of pointer authentication are present, lets add userspace flags KVM_ARM_VCPU_PTRAUTH_ADDRESS and KVM_ARM_VCPU_PTRAUTH_GENERIC. These flags will enable pointer authentication for the KVM guest on a per-vcpu basis through the ioctl KVM_ARM_VCPU_INIT. This features will allow the KVM guest to allow the handling of pointer authentication instructions or to treat them as undefined if not set. Necessary documentations are added to reflect the changes done. Reviewed-by: Dave Martin Signed-off-by: Amit Daniel Kachhap Cc: Mark Rutland Cc: Marc Zyngier Cc: Christoffer Dall Cc: kvmarm@lists.cs.columbia.edu --- Changed since v9: * Fixed tab alignment at few places [Dave Martin]. * Split the system capability checks [Dave Martin]. Documentation/arm64/pointer-authentication.txt | 22 +++++++++++++++++---- Documentation/virtual/kvm/api.txt | 10 ++++++++++ arch/arm64/include/asm/kvm_host.h | 2 +- arch/arm64/include/uapi/asm/kvm.h | 2 ++ arch/arm64/kvm/reset.c | 27 ++++++++++++++++++++++++++ 5 files changed, 58 insertions(+), 5 deletions(-) diff --git a/Documentation/arm64/pointer-authentication.txt b/Documentation/arm64/pointer-authentication.txt index 5baca42..fc71b33 100644 --- a/Documentation/arm64/pointer-authentication.txt +++ b/Documentation/arm64/pointer-authentication.txt @@ -87,7 +87,21 @@ 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 each virtual cpu is +initialised by passing flags KVM_ARM_VCPU_PTRAUTH_[ADDRESS/GENERIC] and +requesting these two separate cpu features to be enabled. The current KVM +guest implementation works by enabling both features together, so both +these userspace flags are checked before enabling pointer authentication. +The separate userspace flag will allow to have no userspace ABI changes +if support is added in the future to allow these two features to be +enabled independently of one another. + +As Arm Architecture specifies that Pointer Authentication feature is +implemented along with the VHE feature so KVM arm64 ptrauth code relies +on VHE mode to be present. + +Additionally, when these vcpu feature flags are not set then KVM will +filter out the Pointer Authentication system key registers from +KVM_GET/SET_REG_* ioctls and mask those features from cpufeature ID +register. Any attempt to use the Pointer Authentication instructions 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 e410a9f..32afe7f 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -2761,6 +2761,16 @@ Possible features: - KVM_ARM_VCPU_PMU_V3: Emulate PMUv3 for the CPU. Depends on KVM_CAP_ARM_PMU_V3. + - KVM_ARM_VCPU_PTRAUTH_ADDRESS: Enables Address Pointer authentication + for arm64 only. + Both KVM_ARM_VCPU_PTRAUTH_ADDRESS and KVM_ARM_VCPU_PTRAUTH_GENERIC + must be requested or neither must be requested. + + - KVM_ARM_VCPU_PTRAUTH_GENERIC: Enables Generic Pointer authentication + for arm64 only. + Both KVM_ARM_VCPU_PTRAUTH_ADDRESS and KVM_ARM_VCPU_PTRAUTH_GENERIC + must be requested or neither must be requested. + - KVM_ARM_VCPU_SVE: Enables SVE for the CPU (arm64 only). Depends on KVM_CAP_ARM_SVE. Requires KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 7eebea7..f772ac2 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -49,7 +49,7 @@ #define KVM_MAX_VCPUS VGIC_V3_MAX_CPUS -#define KVM_VCPU_MAX_FEATURES 5 +#define KVM_VCPU_MAX_FEATURES 7 #define KVM_REQ_SLEEP \ KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h index edd2db8..7b7ac0f 100644 --- a/arch/arm64/include/uapi/asm/kvm.h +++ b/arch/arm64/include/uapi/asm/kvm.h @@ -104,6 +104,8 @@ struct kvm_regs { #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_SVE 4 /* enable SVE for this CPU */ +#define KVM_ARM_VCPU_PTRAUTH_ADDRESS 5 /* VCPU uses address authentication */ +#define KVM_ARM_VCPU_PTRAUTH_GENERIC 6 /* VCPU uses generic authentication */ struct kvm_vcpu_init { __u32 target; diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index 3402543..028d0c6 100644 --- a/arch/arm64/kvm/reset.c +++ b/arch/arm64/kvm/reset.c @@ -221,6 +221,27 @@ static void kvm_vcpu_reset_sve(struct kvm_vcpu *vcpu) memset(vcpu->arch.sve_state, 0, vcpu_sve_state_size(vcpu)); } +static int kvm_vcpu_enable_ptrauth(struct kvm_vcpu *vcpu) +{ + /* Support ptrauth only if the system supports these capabilities. */ + if (!has_vhe()) + return -EINVAL; + + if (!system_supports_address_auth() || + !system_supports_generic_auth()) + return -EINVAL; + /* + * For now make sure that both address/generic pointer authentication + * features are requested by the userspace together. + */ + if (!test_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, vcpu->arch.features) || + !test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, vcpu->arch.features)) + return -EINVAL; + + vcpu->arch.flags |= KVM_ARM64_GUEST_HAS_PTRAUTH; + return 0; +} + /** * kvm_reset_vcpu - sets core registers and sys_regs to reset value * @vcpu: The VCPU pointer @@ -261,6 +282,12 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu) kvm_vcpu_reset_sve(vcpu); } + if (test_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, vcpu->arch.features) || + test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, vcpu->arch.features)) { + if (kvm_vcpu_enable_ptrauth(vcpu)) + goto out; + } + switch (vcpu->arch.target) { default: if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) { -- 2.7.4