From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Zyngier Subject: Re: [PATCH v10 07/12] ARM/ARM64: KVM: Emulate PSCI v0.2 SYSTEM_OFF and SYSTEM_RESET Date: Mon, 28 Apr 2014 15:34:14 +0100 Message-ID: <87d2g1tteh.fsf@approximate.cambridge.arm.com> References: <1398085206-30555-1-git-send-email-anup.patel@linaro.org> <1398085206-30555-8-git-send-email-anup.patel@linaro.org> Mime-Version: 1.0 Content-Type: text/plain Cc: "kvmarm\@lists.cs.columbia.edu" , "kvm\@vger.kernel.org" , "linux-arm-kernel\@lists.infradead.org" , "linaro-kernel\@lists.linaro.org" , "patches\@apm.com" , Christoffer Dall , "rob.herring\@linaro.org" , Pranavkumar Sawargaonkar , Ashwin Chaugule To: Anup Patel Return-path: Received: from fw-tnat.austin.arm.com ([217.140.110.23]:20168 "EHLO collaborate-mta1.arm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751635AbaD1OeR (ORCPT ); Mon, 28 Apr 2014 10:34:17 -0400 In-Reply-To: <1398085206-30555-8-git-send-email-anup.patel@linaro.org> (Anup Patel's message of "Mon, 21 Apr 2014 14:00:01 +0100") Sender: kvm-owner@vger.kernel.org List-ID: On Mon, Apr 21 2014 at 2:00:01 pm BST, Anup Patel wrote: > The PSCI v0.2 SYSTEM_OFF and SYSTEM_RESET functions are system-level > functions hence cannot be fully emulated by in-kernel PSCI emulation code. > > To tackle this, we forward PSCI v0.2 SYSTEM_OFF and SYSTEM_RESET function > calls from vcpu to user space (i.e. QEMU or KVMTOOL) via kvm_run structure > using KVM_EXIT_SYSTEM_EVENT exit reasons. > > Signed-off-by: Anup Patel > Signed-off-by: Pranavkumar Sawargaonkar > Reviewed-by: Christoffer Dall > --- > arch/arm/kvm/psci.c | 32 +++++++++++++++++++++++++++++--- > 1 file changed, 29 insertions(+), 3 deletions(-) > > diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c > index 14e6fa6..4486d0f 100644 > --- a/arch/arm/kvm/psci.c > +++ b/arch/arm/kvm/psci.c > @@ -85,6 +85,23 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu) > return PSCI_RET_SUCCESS; > } > > +static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type) > +{ > + memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event)); > + vcpu->run->system_event.type = type; > + vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT; > +} > + > +static void kvm_psci_system_off(struct kvm_vcpu *vcpu) > +{ > + kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN); > +} > + > +static void kvm_psci_system_reset(struct kvm_vcpu *vcpu) > +{ > + kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET); > +} > + > int kvm_psci_version(struct kvm_vcpu *vcpu) > { > if (test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features)) > @@ -95,6 +112,7 @@ int kvm_psci_version(struct kvm_vcpu *vcpu) > > static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) > { > + int ret = 1; > unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0); > unsigned long val; > > @@ -114,13 +132,21 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) > case PSCI_0_2_FN64_CPU_ON: > val = kvm_psci_vcpu_on(vcpu); > break; > + case PSCI_0_2_FN_SYSTEM_OFF: > + kvm_psci_system_off(vcpu); > + val = PSCI_RET_INTERNAL_FAILURE; > + ret = 0; > + break; > + case PSCI_0_2_FN_SYSTEM_RESET: > + kvm_psci_system_reset(vcpu); > + val = PSCI_RET_INTERNAL_FAILURE; > + ret = 0; > + break; Maybe add a comment about why we set INTERNAL_FAILURE here (we shouldn't be able to come back from such a PSCI call). > case PSCI_0_2_FN_CPU_SUSPEND: > case PSCI_0_2_FN_AFFINITY_INFO: > case PSCI_0_2_FN_MIGRATE: > case PSCI_0_2_FN_MIGRATE_INFO_TYPE: > case PSCI_0_2_FN_MIGRATE_INFO_UP_CPU: > - case PSCI_0_2_FN_SYSTEM_OFF: > - case PSCI_0_2_FN_SYSTEM_RESET: > case PSCI_0_2_FN64_CPU_SUSPEND: > case PSCI_0_2_FN64_AFFINITY_INFO: > case PSCI_0_2_FN64_MIGRATE: > @@ -132,7 +158,7 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) > } > > *vcpu_reg(vcpu, 0) = val; > - return 1; > + return ret; > } > > static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu) Aside from this minor comment: Acked-by: Marc Zyngier M. -- Jazz is not dead. It just smells funny.