From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Zyngier Subject: Re: [PATCH v4 18/21] KVM: ARM64: Add PMU overflow interrupt routing Date: Mon, 30 Nov 2015 18:22:58 +0000 Message-ID: <20151130182258.684c9df6@arm.com> References: <1446186123-11548-1-git-send-email-zhaoshenglong@huawei.com> <1446186123-11548-19-git-send-email-zhaoshenglong@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: , , , , , , , , , To: Shannon Zhao Return-path: Received: from foss.arm.com ([217.140.101.70]:58984 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754655AbbK3SXI (ORCPT ); Mon, 30 Nov 2015 13:23:08 -0500 In-Reply-To: <1446186123-11548-19-git-send-email-zhaoshenglong@huawei.com> Sender: kvm-owner@vger.kernel.org List-ID: On Fri, 30 Oct 2015 14:22:00 +0800 Shannon Zhao wrote: > From: Shannon Zhao > > When calling perf_event_create_kernel_counter to create perf_event, > assign a overflow handler. Then when perf event overflows, set > irq_pending and call kvm_vcpu_kick() to sync the interrupt. > > Signed-off-by: Shannon Zhao > --- > arch/arm/kvm/arm.c | 4 +++ > include/kvm/arm_pmu.h | 4 +++ > virt/kvm/arm/pmu.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++- > 3 files changed, 83 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c > index 78b2869..9c0fec4 100644 > --- a/arch/arm/kvm/arm.c > +++ b/arch/arm/kvm/arm.c > @@ -28,6 +28,7 @@ > #include > #include > #include > +#include > > #define CREATE_TRACE_POINTS > #include "trace.h" > @@ -551,6 +552,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) > > if (ret <= 0 || need_new_vmid_gen(vcpu->kvm)) { > local_irq_enable(); > + kvm_pmu_sync_hwstate(vcpu); This is very weird. Are you only injecting interrupts when a signal is pending? I don't understand how this works... > kvm_vgic_sync_hwstate(vcpu); > preempt_enable(); > kvm_timer_sync_hwstate(vcpu); > @@ -598,6 +600,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) > kvm_guest_exit(); > trace_kvm_exit(kvm_vcpu_trap_get_class(vcpu), *vcpu_pc(vcpu)); > > + kvm_pmu_post_sync_hwstate(vcpu); > + > kvm_vgic_sync_hwstate(vcpu); > > preempt_enable(); > diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h > index acd025a..5e7f943 100644 > --- a/include/kvm/arm_pmu.h > +++ b/include/kvm/arm_pmu.h > @@ -39,6 +39,8 @@ struct kvm_pmu { > }; > > #ifdef CONFIG_KVM_ARM_PMU > +void kvm_pmu_sync_hwstate(struct kvm_vcpu *vcpu); > +void kvm_pmu_post_sync_hwstate(struct kvm_vcpu *vcpu); Please follow the current terminology: _flush_ on VM entry, _sync_ on VM exit. > unsigned long kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u32 select_idx); > void kvm_pmu_disable_counter(struct kvm_vcpu *vcpu, u32 val); > void kvm_pmu_enable_counter(struct kvm_vcpu *vcpu, u32 val, bool all_enable); > @@ -49,6 +51,8 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u32 data, > u32 select_idx); > void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u32 val); > #else > +void kvm_pmu_sync_hwstate(struct kvm_vcpu *vcpu) {} > +void kvm_pmu_post_sync_hwstate(struct kvm_vcpu *vcpu) {} > unsigned long kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u32 select_idx) > { > return 0; > diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c > index 11d1bfb..6d48d9a 100644 > --- a/virt/kvm/arm/pmu.c > +++ b/virt/kvm/arm/pmu.c > @@ -21,6 +21,7 @@ > #include > #include > #include > +#include > > /** > * kvm_pmu_get_counter_value - get PMU counter value > @@ -69,6 +70,78 @@ static void kvm_pmu_stop_counter(struct kvm_pmc *pmc) > } > > /** > + * kvm_pmu_sync_hwstate - sync pmu state for cpu > + * @vcpu: The vcpu pointer > + * > + * Inject virtual PMU IRQ if IRQ is pending for this cpu. > + */ > +void kvm_pmu_sync_hwstate(struct kvm_vcpu *vcpu) > +{ > + struct kvm_pmu *pmu = &vcpu->arch.pmu; > + u32 overflow; > + > + if (!vcpu_mode_is_32bit(vcpu)) > + overflow = vcpu_sys_reg(vcpu, PMOVSSET_EL0); > + else > + overflow = vcpu_cp15(vcpu, c9_PMOVSSET); > + > + if ((pmu->irq_pending || overflow != 0) && (pmu->irq_num != -1)) > + kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id, pmu->irq_num, 1); > + > + pmu->irq_pending = false; > +} > + > +/** > + * kvm_pmu_post_sync_hwstate - post sync pmu state for cpu > + * @vcpu: The vcpu pointer > + * > + * Inject virtual PMU IRQ if IRQ is pending for this cpu when back from guest. > + */ > +void kvm_pmu_post_sync_hwstate(struct kvm_vcpu *vcpu) > +{ > + struct kvm_pmu *pmu = &vcpu->arch.pmu; > + > + if (pmu->irq_pending && (pmu->irq_num != -1)) > + kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id, pmu->irq_num, 1); > + > + pmu->irq_pending = false; > +} > + > +/** > + * When perf event overflows, set irq_pending and call kvm_vcpu_kick() to inject > + * the interrupt. > + */ > +static void kvm_pmu_perf_overflow(struct perf_event *perf_event, > + struct perf_sample_data *data, > + struct pt_regs *regs) > +{ > + struct kvm_pmc *pmc = perf_event->overflow_handler_context; > + struct kvm_vcpu *vcpu = pmc->vcpu; > + struct kvm_pmu *pmu = &vcpu->arch.pmu; > + int idx = pmc->idx; > + > + if (!vcpu_mode_is_32bit(vcpu)) { > + if ((vcpu_sys_reg(vcpu, PMINTENSET_EL1) >> idx) & 0x1) { > + __set_bit(idx, > + (unsigned long *)&vcpu_sys_reg(vcpu, PMOVSSET_EL0)); > + __set_bit(idx, > + (unsigned long *)&vcpu_sys_reg(vcpu, PMOVSCLR_EL0)); > + pmu->irq_pending = true; > + kvm_vcpu_kick(vcpu); > + } > + } else { > + if ((vcpu_cp15(vcpu, c9_PMINTENSET) >> idx) & 0x1) { > + __set_bit(idx, > + (unsigned long *)&vcpu_cp15(vcpu, c9_PMOVSSET)); > + __set_bit(idx, > + (unsigned long *)&vcpu_cp15(vcpu, c9_PMOVSCLR)); > + pmu->irq_pending = true; > + kvm_vcpu_kick(vcpu); There is some obvious code factorization that can be done here. > + } > + } > +} > + > +/** > * kvm_pmu_enable_counter - enable selected PMU counter > * @vcpu: The vcpu pointer > * @val: the value guest writes to PMCNTENSET register > @@ -293,7 +366,8 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u32 data, > /* The initial sample period (overflow count) of an event. */ > attr.sample_period = (-counter) & pmc->bitmask; > > - event = perf_event_create_kernel_counter(&attr, -1, current, NULL, pmc); > + event = perf_event_create_kernel_counter(&attr, -1, current, > + kvm_pmu_perf_overflow, pmc); > if (IS_ERR(event)) { > printk_once("kvm: pmu event creation failed %ld\n", > PTR_ERR(event)); Thanks, M. -- Jazz is not dead. It just smells funny.