Commit 7e484d27 authored by Oliver Upton's avatar Oliver Upton Committed by Marc Zyngier
Browse files

KVM: arm64: Return NOT_SUPPORTED to guest for unknown PSCI version 



A subsequent change to KVM will allow negative returns from SMCCC
handlers to exit to userspace. Make way for this change by explicitly
returning SMCCC_RET_NOT_SUPPORTED to the guest if the VM is configured
to use an unknown PSCI version. Add a WARN since this is undoubtedly a
KVM bug.

Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230404154050.2270077-11-oliver.upton@linux.dev
parent 821d935c

arch/arm64/kvm/psci.c

+5 −2
Original line number Diff line number Diff line
@@ -435,6 +435,7 @@ static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu) 
int kvm_psci_call(struct kvm_vcpu *vcpu)

{

	u32 psci_fn = smccc_get_function(vcpu);

	int version = kvm_psci_version(vcpu);

	unsigned long val;



	val = kvm_psci_check_allowed_function(vcpu, psci_fn);
@@ -443,7 +444,7 @@ int kvm_psci_call(struct kvm_vcpu *vcpu) 
		return 1;

	}



	switch (kvm_psci_version(vcpu)) {

	switch (version) {

	case KVM_ARM_PSCI_1_1:

		return kvm_psci_1_x_call(vcpu, 1);

	case KVM_ARM_PSCI_1_0:
@@ -453,6 +454,8 @@ int kvm_psci_call(struct kvm_vcpu *vcpu) 
	case KVM_ARM_PSCI_0_1:

		return kvm_psci_0_1_call(vcpu);

	default:

		return -EINVAL;

		WARN_ONCE(1, "Unknown PSCI version %d", version);

		smccc_set_retval(vcpu, SMCCC_RET_NOT_SUPPORTED, 0, 0, 0);

		return 1;

	}

}