From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757092AbcBCQYA (ORCPT ); Wed, 3 Feb 2016 11:24:00 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54933 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753148AbcBCQX6 (ORCPT ); Wed, 3 Feb 2016 11:23:58 -0500 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 0/4] KVM: x86: change and fix PIT discard tick policy Date: Wed, 3 Feb 2016 17:23:01 +0100 Message-Id: <1454516585-28491-1-git-send-email-rkrcmar@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [3/4] fixes a bug where legacy NMI watchdog doesn't receive NMIs if a CPU that handles PIT interrupts hangs with masked interrupts. Remaining patches try to make the code nicer where necessary. ([1/4] makes you think that it fixes a bug, but that would be fixed by skipping the path in [3/4].) [3/4] only changes the discard policy. A change that allows legacy NMI watchdog with the reinject policy is below, but conscience doesn't allow me to sign it off. # diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c @@ -274,6 +274,10 @@ static void pit_do_work(struct kthread_work *work) int i; struct kvm_kpit_state *ps = &pit->pit_state; + if (atomic_read(&kvm->arch.vapics_in_nmi_mode) > 0) + kvm_for_each_vcpu(i, vcpu, kvm) + kvm_apic_nmi_wd_deliver(vcpu); + if (ps->reinject && !atomic_xchg(&ps->irq_ack, 0)) return; @@ -289,9 +293,6 @@ static void pit_do_work(struct kthread_work *work) * VCPUs and only when LVT0 is in NMI mode. The interrupt can * also be simultaneously delivered through PIC and IOAPIC. */ - if (atomic_read(&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) Radim Krčmář (4): KVM: x86: fix interrupt dropping race in PIT KVM: x86: refactor PIT state inject_lock KVM: x86: change PIT discard tick policy KVM: x86: remove notifiers from PIT discard policy arch/x86/kvm/i8254.c | 122 ++++++++++++++++++++++++++------------------------- arch/x86/kvm/i8254.h | 4 +- arch/x86/kvm/x86.c | 6 +-- 3 files changed, 67 insertions(+), 65 deletions(-) -- 2.7.0