Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756738AbYLHLri (ORCPT ); Mon, 8 Dec 2008 06:47:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753343AbYLHLiW (ORCPT ); Mon, 8 Dec 2008 06:38:22 -0500 Received: from mx2.redhat.com ([66.187.237.31]:48266 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753317AbYLHLhF (ORCPT ); Mon, 8 Dec 2008 06:37:05 -0500 From: Avi Kivity To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jan Kiszka Subject: [PATCH 27/45] KVM: x86: Optimize NMI watchdog delivery Date: Mon, 8 Dec 2008 13:36:38 +0200 Message-Id: <1228736216-15787-28-git-send-email-avi@redhat.com> In-Reply-To: <1228736216-15787-1-git-send-email-avi@redhat.com> References: <1228736216-15787-1-git-send-email-avi@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3490 Lines: 105 From: Jan Kiszka As suggested by Avi, this patch introduces a counter of VCPUs that have LVT0 set to NMI mode. Only if the counter > 0, we push the PIT ticks via all LAPIC LVT0 lines to enable NMI watchdog support. Signed-off-by: Jan Kiszka Acked-by: Sheng Yang Signed-off-by: Avi Kivity --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/i8254.c | 11 ++++++----- arch/x86/kvm/lapic.c | 23 ++++++++++++++++++++--- 3 files changed, 27 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 59c3ae1..09e6c56 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -361,6 +361,7 @@ struct kvm_arch{ struct kvm_ioapic *vioapic; struct kvm_pit *vpit; struct hlist_head irq_ack_notifier_list; + int vapics_in_nmi_mode; int round_robin_prev_vcpu; unsigned int tss_addr; diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index b6fcf5a..e665d1c 100644 --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -620,11 +620,12 @@ static void __inject_pit_timer_intr(struct kvm *kvm) * LVT0 to NMI delivery. Other PIC interrupts are just sent to * VCPU0, and only if its LVT0 is in EXTINT mode. */ - for (i = 0; i < KVM_MAX_VCPUS; ++i) { - vcpu = kvm->vcpus[i]; - if (vcpu) - kvm_apic_nmi_wd_deliver(vcpu); - } + if (kvm->arch.vapics_in_nmi_mode > 0) + for (i = 0; i < KVM_MAX_VCPUS; ++i) { + vcpu = kvm->vcpus[i]; + if (vcpu) + kvm_apic_nmi_wd_deliver(vcpu); + } } void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 0b0d413..afac68c 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -130,6 +130,11 @@ static inline int apic_lvtt_period(struct kvm_lapic *apic) return apic_get_reg(apic, APIC_LVTT) & APIC_LVT_TIMER_PERIODIC; } +static inline int apic_lvt_nmi_mode(u32 lvt_val) +{ + return (lvt_val & (APIC_MODE_MASK | APIC_LVT_MASKED)) == APIC_DM_NMI; +} + static unsigned int apic_lvt_mask[APIC_LVT_NUM] = { LVT_MASK | APIC_LVT_TIMER_PERIODIC, /* LVTT */ LVT_MASK | APIC_MODE_MASK, /* LVTTHMR */ @@ -672,6 +677,20 @@ static void start_apic_timer(struct kvm_lapic *apic) apic->timer.period))); } +static void apic_manage_nmi_watchdog(struct kvm_lapic *apic, u32 lvt0_val) +{ + int nmi_wd_enabled = apic_lvt_nmi_mode(apic_get_reg(apic, APIC_LVT0)); + + if (apic_lvt_nmi_mode(lvt0_val)) { + if (!nmi_wd_enabled) { + apic_debug("Receive NMI setting on APIC_LVT0 " + "for cpu %d\n", apic->vcpu->vcpu_id); + apic->vcpu->kvm->arch.vapics_in_nmi_mode++; + } + } else if (nmi_wd_enabled) + apic->vcpu->kvm->arch.vapics_in_nmi_mode--; +} + static void apic_mmio_write(struct kvm_io_device *this, gpa_t address, int len, const void *data) { @@ -753,9 +772,7 @@ static void apic_mmio_write(struct kvm_io_device *this, break; case APIC_LVT0: - if (val == APIC_DM_NMI) - apic_debug("Receive NMI setting on APIC_LVT0 " - "for cpu %d\n", apic->vcpu->vcpu_id); + apic_manage_nmi_watchdog(apic, val); case APIC_LVTT: case APIC_LVTTHMR: case APIC_LVTPC: -- 1.6.0.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/