From patchwork Wed Jun 16 21:11:11 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Lalancette X-Patchwork-Id: 106564 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter.kernel.org (8.14.3/8.14.3) with ESMTP id o5GLDcos018263 for ; Wed, 16 Jun 2010 21:13:38 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752034Ab0FPVNf (ORCPT ); Wed, 16 Jun 2010 17:13:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43216 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750728Ab0FPVNe (ORCPT ); Wed, 16 Jun 2010 17:13:34 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o5GLDYPX005750 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 16 Jun 2010 17:13:34 -0400 Received: from localhost.localdomain (vpn-9-133.rdu.redhat.com [10.11.9.133]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o5GLDW57022077; Wed, 16 Jun 2010 17:13:33 -0400 From: Chris Lalancette To: kvm@vger.kernel.org Cc: Chris Lalancette Subject: [PATCH v3 1/3] Introduce a workqueue to deliver PIT timer interrupts. Date: Wed, 16 Jun 2010 17:11:11 -0400 Message-Id: <1276722673-19011-2-git-send-email-clalance@redhat.com> In-Reply-To: <1276722673-19011-1-git-send-email-clalance@redhat.com> References: <1276722673-19011-1-git-send-email-clalance@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.12 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter.kernel.org [140.211.167.41]); Wed, 16 Jun 2010 21:13:39 +0000 (UTC) diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index 188d827..467cc47 100644 --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -34,6 +34,7 @@ #include #include +#include #include "irq.h" #include "i8254.h" @@ -244,11 +245,22 @@ static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian) { struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state, irq_ack_notifier); - raw_spin_lock(&ps->inject_lock); - if (atomic_dec_return(&ps->pit_timer.pending) < 0) + int value; + + spin_lock(&ps->inject_lock); + value = atomic_dec_return(&ps->pit_timer.pending); + if (value < 0) + /* spurious acks can be generated if, for example, the + * PIC is being reset. Handle it gracefully here + */ atomic_inc(&ps->pit_timer.pending); + else if (value > 0) + /* in this case, we had multiple outstanding pit interrupts + * that we needed to inject. Reinject + */ + queue_work(ps->pit->wq, &ps->pit->expired); ps->irq_ack = 1; - raw_spin_unlock(&ps->inject_lock); + spin_unlock(&ps->inject_lock); } void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu) @@ -264,10 +276,10 @@ void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu) hrtimer_start_expires(timer, HRTIMER_MODE_ABS); } -static void destroy_pit_timer(struct kvm_timer *pt) +static void destroy_pit_timer(struct kvm_pit *pit) { - pr_debug("execute del timer!\n"); - hrtimer_cancel(&pt->timer); + hrtimer_cancel(&pit->pit_state.pit_timer.timer); + cancel_work_sync(&pit->expired); } static bool kpit_is_periodic(struct kvm_timer *ktimer) @@ -281,6 +293,60 @@ static struct kvm_timer_ops kpit_ops = { .is_periodic = kpit_is_periodic, }; +static void pit_do_work(struct work_struct *work) +{ + struct kvm_pit *pit = container_of(work, struct kvm_pit, expired); + struct kvm *kvm = pit->kvm; + struct kvm_vcpu *vcpu; + int i; + struct kvm_kpit_state *ps = &pit->pit_state; + int inject = 0; + + /* Try to inject pending interrupts when + * last one has been acked. + */ + spin_lock(&ps->inject_lock); + if (ps->irq_ack) { + ps->irq_ack = 0; + inject = 1; + } + spin_unlock(&ps->inject_lock); + if (inject) { + kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1); + kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0); + + /* + * Provides NMI watchdog support via Virtual Wire mode. + * The route is: PIT -> PIC -> LVT0 in NMI mode. + * + * Note: Our Virtual Wire implementation is simplified, only + * propagating PIT interrupts to all VCPUs when they have set + * LVT0 to NMI delivery. Other PIC interrupts are just sent to + * VCPU0, and only if its LVT0 is in EXTINT mode. + */ + if (kvm->arch.vapics_in_nmi_mode > 0) + kvm_for_each_vcpu(i, vcpu, kvm) + kvm_apic_nmi_wd_deliver(vcpu); + } +} + +static enum hrtimer_restart pit_timer_fn(struct hrtimer *data) +{ + struct kvm_timer *ktimer = container_of(data, struct kvm_timer, timer); + struct kvm_pit *pt = ktimer->kvm->arch.vpit; + + if (ktimer->reinject || !atomic_read(&ktimer->pending)) { + atomic_inc(&ktimer->pending); + queue_work(pt->wq, &pt->expired); + } + + if (ktimer->t_ops->is_periodic(ktimer)) { + hrtimer_add_expires_ns(&ktimer->timer, ktimer->period); + return HRTIMER_RESTART; + } else + return HRTIMER_NORESTART; +} + static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period) { struct kvm_timer *pt = &ps->pit_timer; @@ -292,13 +358,13 @@ static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period) /* TODO The new value only affected after the retriggered */ hrtimer_cancel(&pt->timer); + cancel_work_sync(&ps->pit->expired); pt->period = interval; ps->is_periodic = is_period; - pt->timer.function = kvm_timer_fn; + pt->timer.function = pit_timer_fn; pt->t_ops = &kpit_ops; pt->kvm = ps->pit->kvm; - pt->vcpu = pt->kvm->bsp_vcpu; atomic_set(&pt->pending, 0); ps->irq_ack = 1; @@ -347,7 +413,7 @@ static void pit_load_count(struct kvm *kvm, int channel, u32 val) } break; default: - destroy_pit_timer(&ps->pit_timer); + destroy_pit_timer(kvm->arch.vpit); } } @@ -626,7 +692,14 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags) mutex_init(&pit->pit_state.lock); mutex_lock(&pit->pit_state.lock); - raw_spin_lock_init(&pit->pit_state.inject_lock); + spin_lock_init(&pit->pit_state.inject_lock); + + pit->wq = create_singlethread_workqueue("kvm-pit-wq"); + if (!pit->wq) { + kfree(pit); + return NULL; + } + INIT_WORK(&pit->expired, pit_do_work); kvm->arch.vpit = pit; pit->kvm = kvm; @@ -685,54 +758,10 @@ void kvm_free_pit(struct kvm *kvm) mutex_lock(&kvm->arch.vpit->pit_state.lock); timer = &kvm->arch.vpit->pit_state.pit_timer.timer; hrtimer_cancel(timer); + cancel_work_sync(&kvm->arch.vpit->expired); kvm_free_irq_source_id(kvm, kvm->arch.vpit->irq_source_id); mutex_unlock(&kvm->arch.vpit->pit_state.lock); + destroy_workqueue(kvm->arch.vpit->wq); kfree(kvm->arch.vpit); } } - -static void __inject_pit_timer_intr(struct kvm *kvm) -{ - struct kvm_vcpu *vcpu; - int i; - - kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1); - kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0); - - /* - * Provides NMI watchdog support via Virtual Wire mode. - * The route is: PIT -> PIC -> LVT0 in NMI mode. - * - * Note: Our Virtual Wire implementation is simplified, only - * propagating PIT interrupts to all VCPUs when they have set - * LVT0 to NMI delivery. Other PIC interrupts are just sent to - * VCPU0, and only if its LVT0 is in EXTINT mode. - */ - if (kvm->arch.vapics_in_nmi_mode > 0) - kvm_for_each_vcpu(i, vcpu, kvm) - kvm_apic_nmi_wd_deliver(vcpu); -} - -void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu) -{ - struct kvm_pit *pit = vcpu->kvm->arch.vpit; - struct kvm *kvm = vcpu->kvm; - struct kvm_kpit_state *ps; - - if (pit) { - int inject = 0; - ps = &pit->pit_state; - - /* Try to inject pending interrupts when - * last one has been acked. - */ - raw_spin_lock(&ps->inject_lock); - if (atomic_read(&ps->pit_timer.pending) && ps->irq_ack) { - ps->irq_ack = 0; - inject = 1; - } - raw_spin_unlock(&ps->inject_lock); - if (inject) - __inject_pit_timer_intr(kvm); - } -} diff --git a/arch/x86/kvm/i8254.h b/arch/x86/kvm/i8254.h index 900d6b0..46d08ca 100644 --- a/arch/x86/kvm/i8254.h +++ b/arch/x86/kvm/i8254.h @@ -27,7 +27,7 @@ struct kvm_kpit_state { u32 speaker_data_on; struct mutex lock; struct kvm_pit *pit; - raw_spinlock_t inject_lock; + spinlock_t inject_lock; unsigned long irq_ack; struct kvm_irq_ack_notifier irq_ack_notifier; }; @@ -40,6 +40,8 @@ struct kvm_pit { struct kvm_kpit_state pit_state; int irq_source_id; struct kvm_irq_mask_notifier mask_notifier; + struct workqueue_struct *wq; + struct work_struct expired; }; #define KVM_PIT_BASE_ADDRESS 0x40 diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c index 0f4e488..2095a04 100644 --- a/arch/x86/kvm/irq.c +++ b/arch/x86/kvm/irq.c @@ -90,7 +90,6 @@ EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt); void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu) { kvm_inject_apic_timer_irqs(vcpu); - kvm_inject_pit_timer_irqs(vcpu); /* TODO: PIT, RTC etc. */ } EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs);