From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:58576 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753581AbeA2UK4 (ORCPT ); Mon, 29 Jan 2018 15:10:56 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Marc Zyngier , Christoffer Dall Subject: [PATCH 3.18 18/52] arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls Date: Mon, 29 Jan 2018 13:56:36 +0100 Message-Id: <20180129123628.992889863@linuxfoundation.org> In-Reply-To: <20180129123628.168904217@linuxfoundation.org> References: <20180129123628.168904217@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Marc Zyngier commit acfb3b883f6d6a4b5d27ad7fdded11f6a09ae6dd upstream. KVM doesn't follow the SMCCC when it comes to unimplemented calls, and inject an UNDEF instead of returning an error. Since firmware calls are now used for security mitigation, they are becoming more common, and the undef is counter productive. Instead, let's follow the SMCCC which states that -1 must be returned to the caller when getting an unknown function number. Signed-off-by: Marc Zyngier Signed-off-by: Christoffer Dall Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kvm/handle_exit.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -34,7 +34,7 @@ static int handle_hvc(struct kvm_vcpu *v ret = kvm_psci_call(vcpu); if (ret < 0) { - kvm_inject_undefined(vcpu); + *vcpu_reg(vcpu, 0) = ~0UL; return 1; } @@ -43,7 +43,7 @@ static int handle_hvc(struct kvm_vcpu *v static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run) { - kvm_inject_undefined(vcpu); + *vcpu_reg(vcpu, 0) = ~0UL; return 1; }