Commit aff7cce0 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

KVM: arm64: Allow PtrAuth to be enabled from userspace on non-VHE systems 



Now that the scene is set for enabling PtrAuth on non-VHE, drop
the restrictions preventing userspace from enabling it.

Acked-by: default avatarAndrew Scull <ascull@google.com>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent dfb0589c

arch/arm64/kvm/reset.c

+10 −11
Original line number Diff line number Diff line
@@ -42,6 +42,11 @@ static u32 kvm_ipa_limit; 
#define VCPU_RESET_PSTATE_SVC	(PSR_AA32_MODE_SVC | PSR_AA32_A_BIT | \

				 PSR_AA32_I_BIT | PSR_AA32_F_BIT)



static bool system_has_full_ptr_auth(void)

{

	return system_supports_address_auth() && system_supports_generic_auth();

}



/**

 * kvm_arch_vm_ioctl_check_extension

 *
@@ -80,8 +85,7 @@ int kvm_arch_vm_ioctl_check_extension(struct kvm *kvm, long ext) 
		break;

	case KVM_CAP_ARM_PTRAUTH_ADDRESS:

	case KVM_CAP_ARM_PTRAUTH_GENERIC:

		r = has_vhe() && system_supports_address_auth() &&

				 system_supports_generic_auth();

		r = system_has_full_ptr_auth();

		break;

	default:

		r = 0;
@@ -205,19 +209,14 @@ static void kvm_vcpu_reset_sve(struct kvm_vcpu *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.

	 * 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))

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

	    !system_has_full_ptr_auth())

		return -EINVAL;



	vcpu->arch.flags |= KVM_ARM64_GUEST_HAS_PTRAUTH;