From a22fa321d13b0264976cbbc1d22f4c27c41d3642 Mon Sep 17 00:00:00 2001 From: Amit Daniel Kachhap Date: Tue, 23 Apr 2019 10:12:36 +0530 Subject: KVM: arm64: Add userspace flag to enable pointer authentication 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 Signed-off-by: Marc Zyngier --- arch/arm64/kvm/reset.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) (limited to 'arch/arm64/kvm') diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index 3402543fdcd3..028d0c604652 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)) { -- cgit v1.2.3