From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sudeep Holla Subject: Re: [PATCH 1/6] ARM: kvm: psci: fix handling of unimplemented functions Date: Fri, 29 May 2015 14:04:49 +0100 Message-ID: <556863F1.10902@arm.com> References: <1432901799-18359-1-git-send-email-lorenzo.pieralisi@arm.com> <1432901799-18359-2-git-send-email-lorenzo.pieralisi@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1432901799-18359-2-git-send-email-lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Lorenzo Pieralisi , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" Cc: Sudeep Holla , Christoffer Dall , Anup Patel , Marc Zyngier , Will Deacon , Catalin Marinas , Mark Rutland List-Id: devicetree@vger.kernel.org On 29/05/15 13:16, Lorenzo Pieralisi wrote: > 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. > > Signed-off-by: Lorenzo Pieralisi > Reported-by: Sudeep Holla > Cc: Christoffer Dall > Cc: Anup Patel > Cc: Marc Zyngier > --- > arch/arm/kvm/psci.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c > index 7e9398c..ec5943b 100644 > --- a/arch/arm/kvm/psci.c > +++ b/arch/arm/kvm/psci.c > @@ -273,7 +273,8 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) > ret = 0; > break; > default: > - return -EINVAL; > + val = PSCI_RET_NOT_SUPPORTED; > + break; IMO we can remove all the other optional non-implemented PSCI functions (e.g. KVM_PSCI_FN_MIGRATE, KVM_PSCI_FN_CPU_SUSPEND, ..etc) returning PSCI_RET_NOT_SUPPORTED here as they will be then automatically covered by default case. Otherwise looks good to me: Acked-by: Sudeep Holla Regards, Sudeep -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: sudeep.holla@arm.com (Sudeep Holla) Date: Fri, 29 May 2015 14:04:49 +0100 Subject: [PATCH 1/6] ARM: kvm: psci: fix handling of unimplemented functions In-Reply-To: <1432901799-18359-2-git-send-email-lorenzo.pieralisi@arm.com> References: <1432901799-18359-1-git-send-email-lorenzo.pieralisi@arm.com> <1432901799-18359-2-git-send-email-lorenzo.pieralisi@arm.com> Message-ID: <556863F1.10902@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 29/05/15 13:16, Lorenzo Pieralisi wrote: > 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. > > Signed-off-by: Lorenzo Pieralisi > Reported-by: Sudeep Holla > Cc: Christoffer Dall > Cc: Anup Patel > Cc: Marc Zyngier > --- > arch/arm/kvm/psci.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c > index 7e9398c..ec5943b 100644 > --- a/arch/arm/kvm/psci.c > +++ b/arch/arm/kvm/psci.c > @@ -273,7 +273,8 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) > ret = 0; > break; > default: > - return -EINVAL; > + val = PSCI_RET_NOT_SUPPORTED; > + break; IMO we can remove all the other optional non-implemented PSCI functions (e.g. KVM_PSCI_FN_MIGRATE, KVM_PSCI_FN_CPU_SUSPEND, ..etc) returning PSCI_RET_NOT_SUPPORTED here as they will be then automatically covered by default case. Otherwise looks good to me: Acked-by: Sudeep Holla Regards, Sudeep