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Commit e2d99736 authored by Lorenzo Pieralisi's avatar Lorenzo Pieralisi Committed by Marc Zyngier
Browse files

ARM: kvm: psci: fix handling of unimplemented functions 



According to the PSCI specification and the SMC/HVC calling
convention, PSCI function_ids that are not implemented must
return NOT_SUPPORTED as return value.

Current KVM implementation takes an unhandled PSCI function_id
as an error and injects an undefined instruction into the guest
if PSCI implementation is called with a function_id that is not
handled by the resident PSCI version (ie it is not implemented),
which is not the behaviour expected by a guest when calling a
PSCI function_id that is not implemented.

This patch fixes this issue by returning NOT_SUPPORTED whenever
the kvm PSCI call is executed for a function_id that is not
implemented by the PSCI kvm layer.

Cc: <stable@vger.kernel.org> # 3.18+
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: default avatarSudeep Holla <sudeep.holla@arm.com>
Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 921ef1e1

arch/arm/kvm/psci.c

+3 −13
Original line number Diff line number Diff line
@@ -230,10 +230,6 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) 
	case PSCI_0_2_FN64_AFFINITY_INFO:

		val = kvm_psci_vcpu_affinity_info(vcpu);

		break;

	case PSCI_0_2_FN_MIGRATE:

	case PSCI_0_2_FN64_MIGRATE:

		val = PSCI_RET_NOT_SUPPORTED;

		break;

	case PSCI_0_2_FN_MIGRATE_INFO_TYPE:

		/*

		 * Trusted OS is MP hence does not require migration
@@ -242,10 +238,6 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) 
		 */

		val = PSCI_0_2_TOS_MP;

		break;

	case PSCI_0_2_FN_MIGRATE_INFO_UP_CPU:

	case PSCI_0_2_FN64_MIGRATE_INFO_UP_CPU:

		val = PSCI_RET_NOT_SUPPORTED;

		break;

	case PSCI_0_2_FN_SYSTEM_OFF:

		kvm_psci_system_off(vcpu);

		/*
@@ -271,7 +263,8 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) 
		ret = 0;

		break;

	default:

		return -EINVAL;

		val = PSCI_RET_NOT_SUPPORTED;

		break;

	}



	*vcpu_reg(vcpu, 0) = val;
@@ -291,12 +284,9 @@ static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu) 
	case KVM_PSCI_FN_CPU_ON:

		val = kvm_psci_vcpu_on(vcpu);

		break;

	case KVM_PSCI_FN_CPU_SUSPEND:

	case KVM_PSCI_FN_MIGRATE:

	default:

		val = PSCI_RET_NOT_SUPPORTED;

		break;

	default:

		return -EINVAL;

	}



	*vcpu_reg(vcpu, 0) = val;