From patchwork Thu Jul 9 13:13:32 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gleb Natapov X-Patchwork-Id: 34812 Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n69DDvHZ006215 for ; Thu, 9 Jul 2009 13:13:57 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759143AbZGINNf (ORCPT ); Thu, 9 Jul 2009 09:13:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759660AbZGINNf (ORCPT ); Thu, 9 Jul 2009 09:13:35 -0400 Received: from mx2.redhat.com ([66.187.237.31]:56923 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759070AbZGINNf (ORCPT ); Thu, 9 Jul 2009 09:13:35 -0400 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n69DDY4l022350 for ; Thu, 9 Jul 2009 09:13:34 -0400 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n69DDXDm032752; Thu, 9 Jul 2009 09:13:34 -0400 Received: from dhcp-1-237.tlv.redhat.com (dhcp-1-237.tlv.redhat.com [10.35.1.237]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id n69DDWSM011010; Thu, 9 Jul 2009 09:13:33 -0400 Received: by dhcp-1-237.tlv.redhat.com (Postfix, from userid 13519) id 64FDB18D479; Thu, 9 Jul 2009 16:13:32 +0300 (IDT) Date: Thu, 9 Jul 2009 16:13:32 +0300 From: Gleb Natapov To: avi@redhat.com Cc: kvm@vger.kernel.org Subject: [PATCH] Move irq routing data structure to rcu locking Message-ID: <20090709131332.GW28046@redhat.com> MIME-Version: 1.0 Content-Disposition: inline X-Scanned-By: MIMEDefang 2.58 on 172.16.27.26 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Change it from list to array to make RCU handling simpler. Signed-off-by: Gleb Natapov --- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index f54a0d3..12d8d2b 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -161,7 +161,8 @@ struct kvm { struct mutex irq_lock; #ifdef CONFIG_HAVE_KVM_IRQCHIP - struct list_head irq_routing; /* of kvm_kernel_irq_routing_entry */ + struct kvm_kernel_irq_routing_entry *irq_routing; + spinlock_t irq_routing_lock; struct hlist_head mask_notifier_list; #endif diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c index 7af18b8..a87f8ac 100644 --- a/virt/kvm/irq_comm.c +++ b/virt/kvm/irq_comm.c @@ -148,7 +148,8 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level) * IOAPIC. So set the bit in both. The guest will ignore * writes to the unused one. */ - list_for_each_entry(e, &kvm->irq_routing, link) + rcu_read_lock(); + for (e = rcu_dereference(kvm->irq_routing); e && e->set; e++) { if (e->gsi == irq) { int r = e->set(e, kvm, sig_level); if (r < 0) @@ -156,6 +157,8 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level) ret = r + ((ret < 0) ? 0 : ret); } + } + rcu_read_unlock(); return ret; } @@ -168,12 +171,15 @@ void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin) trace_kvm_ack_irq(irqchip, pin); - list_for_each_entry(e, &kvm->irq_routing, link) + rcu_read_lock(); + for (e = rcu_dereference(kvm->irq_routing); e && e->set; e++) { if (e->irqchip.irqchip == irqchip && e->irqchip.pin == pin) { gsi = e->gsi; break; } + } + rcu_read_unlock(); hlist_for_each_entry(kian, n, &kvm->arch.irq_ack_notifier_list, link) if (kian->gsi == gsi) @@ -264,19 +270,11 @@ void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask) kimn->func(kimn, mask); } -static void __kvm_free_irq_routing(struct list_head *irq_routing) -{ - struct kvm_kernel_irq_routing_entry *e, *n; - - list_for_each_entry_safe(e, n, irq_routing, link) - kfree(e); -} - void kvm_free_irq_routing(struct kvm *kvm) { - mutex_lock(&kvm->irq_lock); - __kvm_free_irq_routing(&kvm->irq_routing); - mutex_unlock(&kvm->irq_lock); + /* Called only during vm destruction. Nobody can use the pointer + at this stage */ + kfree(kvm->irq_routing); } static int setup_routing_entry(struct kvm_kernel_irq_routing_entry *e, @@ -326,43 +324,39 @@ int kvm_set_irq_routing(struct kvm *kvm, unsigned nr, unsigned flags) { - struct list_head irq_list = LIST_HEAD_INIT(irq_list); - struct list_head tmp = LIST_HEAD_INIT(tmp); - struct kvm_kernel_irq_routing_entry *e = NULL; + struct kvm_kernel_irq_routing_entry *new, *old; unsigned i; int r; + /* last element is left zeroed and indicates the end of the array */ + new = kzalloc(sizeof(*new) * (nr + 1), GFP_KERNEL); + + if (!new) + return -ENOMEM; + for (i = 0; i < nr; ++i) { r = -EINVAL; if (ue->gsi >= KVM_MAX_IRQ_ROUTES) goto out; if (ue->flags) goto out; - r = -ENOMEM; - e = kzalloc(sizeof(*e), GFP_KERNEL); - if (!e) - goto out; - r = setup_routing_entry(e, ue); + r = setup_routing_entry(new + i, ue); if (r) goto out; ++ue; - list_add(&e->link, &irq_list); - e = NULL; } - mutex_lock(&kvm->irq_lock); - list_splice(&kvm->irq_routing, &tmp); - INIT_LIST_HEAD(&kvm->irq_routing); - list_splice(&irq_list, &kvm->irq_routing); - INIT_LIST_HEAD(&irq_list); - list_splice(&tmp, &irq_list); - mutex_unlock(&kvm->irq_lock); + spin_lock(&kvm->irq_routing_lock); + old = kvm->irq_routing; + rcu_assign_pointer(kvm->irq_routing, new); + spin_unlock(&kvm->irq_routing_lock); + synchronize_rcu(); r = 0; + new = old; out: - kfree(e); - __kvm_free_irq_routing(&irq_list); + kfree(new); return r; } diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index cf20dc1..8e3fd3f 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -945,7 +945,7 @@ static struct kvm *kvm_create_vm(void) if (IS_ERR(kvm)) goto out; #ifdef CONFIG_HAVE_KVM_IRQCHIP - INIT_LIST_HEAD(&kvm->irq_routing); + spin_lock_init(&kvm->irq_routing_lock); INIT_HLIST_HEAD(&kvm->mask_notifier_list); #endif