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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 17BDFC10F12 for ; Mon, 15 Apr 2019 11:16:05 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id C669C2087C for ; Mon, 15 Apr 2019 11:16:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C669C2087C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 70E344A4C1; Mon, 15 Apr 2019 07:16:04 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id l4+7wTWP-eCO; Mon, 15 Apr 2019 07:16:02 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id E2BC54A4E5; Mon, 15 Apr 2019 07:16:02 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id ACD154A4B0 for ; Mon, 15 Apr 2019 07:16:01 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id nlwCWQVhY6GX for ; Mon, 15 Apr 2019 07:16:00 -0400 (EDT) Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 8AF8D4A483 for ; Mon, 15 Apr 2019 07:15:59 -0400 (EDT) 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 0BF401684; Mon, 15 Apr 2019 04:15:59 -0700 (PDT) Received: from donnerap.arm.com (donnerap.cambridge.arm.com [10.1.197.44]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1C7383F706; Mon, 15 Apr 2019 04:15:56 -0700 (PDT) From: Andre Przywara To: Marc Zyngier , Christoffer Dall Subject: [PATCH v5 2/3] KVM: arm/arm64: Add save/restore support for firmware workaround state Date: Mon, 15 Apr 2019 12:15:41 +0100 Message-Id: <20190415111542.119788-3-andre.przywara@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190415111542.119788-1-andre.przywara@arm.com> References: <20190415111542.119788-1-andre.przywara@arm.com> Cc: kvm@vger.kernel.org, Jeremy Linton , kvmarm@lists.cs.columbia.edu, Steven Price , Dave Martin , linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu Message-ID: <20190415111541.DyeAhGwxbW2Y3srwf2yGS9qDFbPO4O3pjtwUT0qP0v4@z> KVM implements the firmware interface for mitigating cache speculation vulnerabilities. Guests may use this interface to ensure mitigation is active. If we want to migrate such a guest to a host with a different support level for those workarounds, migration might need to fail, to ensure that critical guests don't loose their protection. Introduce a way for userland to save and restore the workarounds state. On restoring we do checks that make sure we don't downgrade our mitigation level. Signed-off-by: Andre Przywara --- arch/arm/include/asm/kvm_emulate.h | 10 ++ arch/arm/include/uapi/asm/kvm.h | 12 +++ arch/arm64/include/asm/kvm_emulate.h | 14 +++ arch/arm64/include/uapi/asm/kvm.h | 10 ++ virt/kvm/arm/psci.c | 139 ++++++++++++++++++++++++--- 5 files changed, 170 insertions(+), 15 deletions(-) diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h index 8927cae7c966..663a02d7e6f4 100644 --- a/arch/arm/include/asm/kvm_emulate.h +++ b/arch/arm/include/asm/kvm_emulate.h @@ -283,6 +283,16 @@ static inline unsigned long kvm_vcpu_get_mpidr_aff(struct kvm_vcpu *vcpu) return vcpu_cp15(vcpu, c0_MPIDR) & MPIDR_HWID_BITMASK; } +static inline bool kvm_arm_get_vcpu_workaround_2_flag(struct kvm_vcpu *vcpu) +{ + return false; +} + +static inline void kvm_arm_set_vcpu_workaround_2_flag(struct kvm_vcpu *vcpu, + bool flag) +{ +} + static inline void kvm_vcpu_set_be(struct kvm_vcpu *vcpu) { *vcpu_cpsr(vcpu) |= PSR_E_BIT; diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h index 4602464ebdfb..dfce6fdbd03b 100644 --- a/arch/arm/include/uapi/asm/kvm.h +++ b/arch/arm/include/uapi/asm/kvm.h @@ -214,6 +214,18 @@ struct kvm_vcpu_events { #define KVM_REG_ARM_FW_REG(r) (KVM_REG_ARM | KVM_REG_SIZE_U64 | \ KVM_REG_ARM_FW | ((r) & 0xffff)) #define KVM_REG_ARM_PSCI_VERSION KVM_REG_ARM_FW_REG(0) +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1 KVM_REG_ARM_FW_REG(1) + /* Higher values mean better protection. */ +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL 0 +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_AVAIL 1 +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_UNAFFECTED 2 +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2 KVM_REG_ARM_FW_REG(2) + /* Higher values mean better protection. */ +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL 0 +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNKNOWN 1 +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL 2 +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNAFFECTED 3 +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED (1U << 4) /* Device Control API: ARM VGIC */ #define KVM_DEV_ARM_VGIC_GRP_ADDR 0 diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index d3842791e1c4..c00c17c9adb6 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -348,6 +348,20 @@ static inline unsigned long kvm_vcpu_get_mpidr_aff(struct kvm_vcpu *vcpu) return vcpu_read_sys_reg(vcpu, MPIDR_EL1) & MPIDR_HWID_BITMASK; } +static inline bool kvm_arm_get_vcpu_workaround_2_flag(struct kvm_vcpu *vcpu) +{ + return vcpu->arch.workaround_flags & VCPU_WORKAROUND_2_FLAG; +} + +static inline void kvm_arm_set_vcpu_workaround_2_flag(struct kvm_vcpu *vcpu, + bool flag) +{ + if (flag) + vcpu->arch.workaround_flags |= VCPU_WORKAROUND_2_FLAG; + else + vcpu->arch.workaround_flags &= ~VCPU_WORKAROUND_2_FLAG; +} + static inline void kvm_vcpu_set_be(struct kvm_vcpu *vcpu) { if (vcpu_mode_is_32bit(vcpu)) { diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h index 97c3478ee6e7..e75a81a7716f 100644 --- a/arch/arm64/include/uapi/asm/kvm.h +++ b/arch/arm64/include/uapi/asm/kvm.h @@ -225,6 +225,16 @@ struct kvm_vcpu_events { #define KVM_REG_ARM_FW_REG(r) (KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \ KVM_REG_ARM_FW | ((r) & 0xffff)) #define KVM_REG_ARM_PSCI_VERSION KVM_REG_ARM_FW_REG(0) +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1 KVM_REG_ARM_FW_REG(1) +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL 0 +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_AVAIL 1 +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_UNAFFECTED 2 +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2 KVM_REG_ARM_FW_REG(2) +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL 0 +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNKNOWN 1 +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL 2 +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNAFFECTED 3 +#define KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED (1U << 4) /* Device Control API: ARM VGIC */ #define KVM_DEV_ARM_VGIC_GRP_ADDR 0 diff --git a/virt/kvm/arm/psci.c b/virt/kvm/arm/psci.c index 1da53e0e38f7..c82d90aad3ea 100644 --- a/virt/kvm/arm/psci.c +++ b/virt/kvm/arm/psci.c @@ -449,42 +449,103 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu) { - return 1; /* PSCI version */ + return 3; /* PSCI version and two workaround registers */ } int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices) { - if (put_user(KVM_REG_ARM_PSCI_VERSION, uindices)) + if (put_user(KVM_REG_ARM_PSCI_VERSION, uindices++)) + return -EFAULT; + + if (put_user(KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1, uindices++)) + return -EFAULT; + + if (put_user(KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2, uindices++)) return -EFAULT; return 0; } +#define KVM_REG_FEATURE_LEVEL_WIDTH 4 +#define KVM_REG_FEATURE_LEVEL_MASK (BIT(KVM_REG_FEATURE_LEVEL_WIDTH) - 1) + +/* + * Convert the workaround level into an easy-to-compare number, where higher + * values mean better protection. + */ +static int get_kernel_wa_level(u64 regid) +{ + switch (regid) { + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1: + switch (kvm_arm_harden_branch_predictor()) { + case KVM_BP_HARDEN_UNKNOWN: + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL; + case KVM_BP_HARDEN_NEEDED: + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_AVAIL; + case KVM_BP_HARDEN_MITIGATED: + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_UNAFFECTED; + } + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL; + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2: + switch (kvm_arm_have_ssbd()) { + case KVM_SSBD_FORCE_DISABLE: + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL; + case KVM_SSBD_KERNEL: + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL; + case KVM_SSBD_FORCE_ENABLE: + case KVM_SSBD_MITIGATED: + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNAFFECTED; + case KVM_SSBD_UNKNOWN: + default: + return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNKNOWN; + } + } + + return -EINVAL; +} + int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) { - if (reg->id == KVM_REG_ARM_PSCI_VERSION) { - void __user *uaddr = (void __user *)(long)reg->addr; - u64 val; + void __user *uaddr = (void __user *)(long)reg->addr; + u64 val; + switch (reg->id) { + case KVM_REG_ARM_PSCI_VERSION: val = kvm_psci_version(vcpu, vcpu->kvm); - if (copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id))) - return -EFAULT; + break; + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1: + val = get_kernel_wa_level(reg->id) & KVM_REG_FEATURE_LEVEL_MASK; + break; + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2: + val = get_kernel_wa_level(reg->id) & KVM_REG_FEATURE_LEVEL_MASK; - return 0; + if (val == KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL && + kvm_arm_get_vcpu_workaround_2_flag(vcpu)) + val |= KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED; + break; + default: + return -ENOENT; } - return -EINVAL; + if (copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id))) + return -EFAULT; + + return 0; } int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) { - if (reg->id == KVM_REG_ARM_PSCI_VERSION) { - void __user *uaddr = (void __user *)(long)reg->addr; - bool wants_02; - u64 val; + void __user *uaddr = (void __user *)(long)reg->addr; + u64 val; + int wa_level; + + if (copy_from_user(&val, uaddr, KVM_REG_SIZE(reg->id))) + return -EFAULT; - if (copy_from_user(&val, uaddr, KVM_REG_SIZE(reg->id))) - return -EFAULT; + switch (reg->id) { + case KVM_REG_ARM_PSCI_VERSION: + { + bool wants_02; wants_02 = test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features); @@ -501,6 +562,54 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) vcpu->kvm->arch.psci_version = val; return 0; } + break; + } + + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1: + if (val & ~KVM_REG_FEATURE_LEVEL_MASK) + return -EINVAL; + + if (get_kernel_wa_level(reg->id) < val) + return -EINVAL; + + return 0; + + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2: + if (val & ~(KVM_REG_FEATURE_LEVEL_MASK | + KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED)) + return -EINVAL; + + wa_level = val & KVM_REG_FEATURE_LEVEL_MASK; + + if (get_kernel_wa_level(reg->id) < wa_level) + return -EINVAL; + + /* The enabled bit must not be set unless the level is AVAIL. */ + if (wa_level != KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL && + wa_level != val) + return -EINVAL; + + /* Are we finished or do we need to check the enable bit ? */ + if (kvm_arm_have_ssbd() != KVM_SSBD_KERNEL) + return 0; + + /* + * If this kernel supports the workaround to be switched on + * or off, make sure it matches the requested setting. + */ + switch (wa_level) { + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL: + kvm_arm_set_vcpu_workaround_2_flag(vcpu, + val & KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED); + break; + case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNAFFECTED: + kvm_arm_set_vcpu_workaround_2_flag(vcpu, true); + break; + } + + return 0; + default: + return -ENOENT; } return -EINVAL; -- 2.17.1 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm