From patchwork Wed Feb 17 19:14:50 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= X-Patchwork-Id: 8342651 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 08C68C0553 for ; Wed, 17 Feb 2016 19:18:15 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 034E6202EB for ; Wed, 17 Feb 2016 19:18:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B096A20270 for ; Wed, 17 Feb 2016 19:18:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161726AbcBQTP2 (ORCPT ); Wed, 17 Feb 2016 14:15:28 -0500 Received: from mx1.redhat.com ([209.132.183.28]:60650 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423766AbcBQTP0 (ORCPT ); Wed, 17 Feb 2016 14:15:26 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (Postfix) with ESMTPS id 4F422C0A8484; Wed, 17 Feb 2016 19:15:26 +0000 (UTC) Received: from potion ([10.34.1.163]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with SMTP id u1HJFNoT029707; Wed, 17 Feb 2016 14:15:24 -0500 Received: by potion (sSMTP sendmail emulation); Wed, 17 Feb 2016 20:15:23 +0100 From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= To: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org, Paolo Bonzini , Yuki Shibuya Subject: [PATCH v2 08/14] KVM: x86: remove notifiers from PIT discard policy Date: Wed, 17 Feb 2016 20:14:50 +0100 Message-Id: <1455736496-374-9-git-send-email-rkrcmar@redhat.com> In-Reply-To: <1455736496-374-1-git-send-email-rkrcmar@redhat.com> References: <1455736496-374-1-git-send-email-rkrcmar@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-5.9 required=5.0 tests=BAYES_00,HK_RANDOM_FROM, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Discard policy doesn't rely on information from notifiers, so we don't need to register notifiers unconditionally. We kept correct counts in case userspace switched between policies during runtime, but that can be avoided by reseting the state. Signed-off-by: Radim Kr?má? --- v2: * lock the ioctl * rebase arch/x86/kvm/i8254.c | 38 +++++++++++++++++++++++++++----------- arch/x86/kvm/i8254.h | 1 + arch/x86/kvm/x86.c | 12 ++++++++++-- 3 files changed, 38 insertions(+), 13 deletions(-) diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index 01f9c70ebc21..e514f7fa0093 100644 --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -225,7 +225,7 @@ static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian) * inc(pending) in pit_timer_fn and xchg(irq_ack, 0) in pit_do_work. */ smp_mb(); - if (atomic_dec_if_positive(&ps->pending) > 0 && ps->reinject) + if (atomic_dec_if_positive(&ps->pending) > 0) queue_kthread_work(&ps->pit->worker, &ps->pit->expired); } @@ -301,6 +301,27 @@ static inline void kvm_pit_reset_reinject(struct kvm_pit *pit) atomic_set(&pit->pit_state.irq_ack, 1); } +void kvm_pit_set_reinject(struct kvm_pit *pit, bool reinject) +{ + struct kvm_kpit_state *ps = &pit->pit_state; + struct kvm *kvm = pit->kvm; + + if (ps->reinject == reinject) + return; + + if (reinject) { + /* The initial state is preserved while ps->reinject == 0. */ + kvm_pit_reset_reinject(pit); + kvm_register_irq_ack_notifier(kvm, &ps->irq_ack_notifier); + kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier); + } else { + kvm_unregister_irq_ack_notifier(kvm, &ps->irq_ack_notifier); + kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier); + } + + ps->reinject = reinject; +} + static void create_pit_timer(struct kvm_pit *pit, u32 val, int is_period) { struct kvm_kpit_state *ps = &pit->pit_state; @@ -681,15 +702,14 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags) pit_state = &pit->pit_state; pit_state->pit = pit; hrtimer_init(&pit_state->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); + pit_state->irq_ack_notifier.gsi = 0; pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq; - kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier); - pit_state->reinject = true; + pit->mask_notifier.func = pit_mask_notifer; kvm_pit_reset(pit); - pit->mask_notifier.func = pit_mask_notifer; - kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier); + kvm_pit_set_reinject(pit, true); kvm_iodevice_init(&pit->dev, &pit_dev_ops); ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, KVM_PIT_BASE_ADDRESS, @@ -712,8 +732,7 @@ fail_unregister: kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev); fail: - kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier); - kvm_unregister_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier); + kvm_pit_set_reinject(pit, false); kvm_free_irq_source_id(kvm, pit->irq_source_id); kthread_stop(pit->worker_task); kfree(pit); @@ -728,10 +747,7 @@ void kvm_free_pit(struct kvm *kvm) kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &kvm->arch.vpit->dev); kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &kvm->arch.vpit->speaker_dev); - kvm_unregister_irq_mask_notifier(kvm, 0, - &kvm->arch.vpit->mask_notifier); - kvm_unregister_irq_ack_notifier(kvm, - &kvm->arch.vpit->pit_state.irq_ack_notifier); + kvm_pit_set_reinject(kvm->arch.vpit, false); timer = &kvm->arch.vpit->pit_state.timer; hrtimer_cancel(timer); flush_kthread_work(&kvm->arch.vpit->expired); diff --git a/arch/x86/kvm/i8254.h b/arch/x86/kvm/i8254.h index 568d87ec3698..47a96e803aab 100644 --- a/arch/x86/kvm/i8254.h +++ b/arch/x86/kvm/i8254.h @@ -63,5 +63,6 @@ void kvm_free_pit(struct kvm *kvm); void kvm_pit_load_count(struct kvm_pit *pit, int channel, u32 val, int hpet_legacy_start); +void kvm_pit_set_reinject(struct kvm_pit *pit, bool reinject); #endif diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index f2f7ba74da6b..785cc781673d 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3683,10 +3683,18 @@ static int kvm_vm_ioctl_set_pit2(struct kvm *kvm, struct kvm_pit_state2 *ps) static int kvm_vm_ioctl_reinject(struct kvm *kvm, struct kvm_reinject_control *control) { - if (!kvm->arch.vpit) + struct kvm_pit *pit = kvm->arch.vpit; + + if (!pit) return -ENXIO; - kvm->arch.vpit->pit_state.reinject = control->pit_reinject; + /* pit->pit_state.lock was overloaded to prevent userspace from getting + * an inconsistent state after running multiple KVM_REINJECT_CONTROL + * ioctls in parallel. Use a separate lock if that ioctl isn't rare. + */ + mutex_lock(&pit->pit_state.lock); + kvm_pit_set_reinject(pit, control->pit_reinject); + mutex_unlock(&pit->pit_state.lock); return 0; }