Commit baa28a53 authored by Oliver Upton's avatar Oliver Upton
Browse files

KVM: arm64: Hoist PAuth checks into KVM_ARM_VCPU_INIT ioctl 

Test for feature support in the ioctl handler rather than
kvm_reset_vcpu(). Continue to uphold our all-or-nothing policy with
address and generic pointer authentication.

Link: https://lore.kernel.org/r/20230920195036.1169791-5-oliver.upton@linux.dev


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent be9c0c01

arch/arm64/kvm/arm.c

+13 −0
Original line number Diff line number Diff line
@@ -1203,6 +1203,11 @@ static unsigned long system_supported_vcpu_features(void) 
	if (!system_supports_sve())

		clear_bit(KVM_ARM_VCPU_SVE, &features);



	if (!system_has_full_ptr_auth()) {

		clear_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, &features);

		clear_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, &features);

	}



	return features;

}
@@ -1223,6 +1228,14 @@ static int kvm_vcpu_init_check_features(struct kvm_vcpu *vcpu, 
	if (features & ~system_supported_vcpu_features())

		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, &features) !=

	    test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, &features))

		return -EINVAL;



	if (!test_bit(KVM_ARM_VCPU_EL1_32BIT, &features))

		return 0;

arch/arm64/kvm/reset.c

+3 −18
Original line number Diff line number Diff line
@@ -165,20 +165,9 @@ 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)

static void kvm_vcpu_enable_ptrauth(struct kvm_vcpu *vcpu)

{

	/*

	 * For now make sure that both address/generic pointer authentication

	 * features are requested by the userspace together and the system

	 * supports these capabilities.

	 */

	if (!test_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, vcpu->arch.features) ||

	    !test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, vcpu->arch.features) ||

	    !system_has_full_ptr_auth())

		return -EINVAL;



	vcpu_set_flag(vcpu, GUEST_HAS_PTRAUTH);

	return 0;

}



/**
@@ -233,12 +222,8 @@ int kvm_reset_vcpu(struct kvm_vcpu *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)) {

			ret = -EINVAL;

			goto out;

		}

	}

	    test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, vcpu->arch.features))

		kvm_vcpu_enable_ptrauth(vcpu);



	if (vcpu_el1_is_32bit(vcpu))

		pstate = VCPU_RESET_PSTATE_SVC;