From 23930f9521c9c4d4aa96cdb9d1e1703f3782bb94 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Fri, 26 Sep 2008 09:30:52 +0200 Subject: KVM: x86: Enable NMI Watchdog via in-kernel PIT source LINT0 of the LAPIC can be used to route PIT events as NMI watchdog ticks into the guest. This patch aligns the in-kernel irqchip emulation with the user space irqchip with already supports this feature. The trick is to route PIT interrupts to all LAPIC's LVT0 lines. Rebased and slightly polished patch originally posted by Sheng Yang. Signed-off-by: Jan Kiszka Signed-off-by: Sheng Yang Signed-off-by: Avi Kivity --- arch/x86/kvm/i8254.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'arch/x86/kvm/i8254.c') diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index 59ebd37ad79..580cc1d01c7 100644 --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -603,10 +603,25 @@ void kvm_free_pit(struct kvm *kvm) static void __inject_pit_timer_intr(struct kvm *kvm) { + struct kvm_vcpu *vcpu; + int i; + mutex_lock(&kvm->lock); kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1); kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0); mutex_unlock(&kvm->lock); + + /* + * Provides NMI watchdog support in IOAPIC mode. + * The route is: PIT -> PIC -> LVT0 in NMI mode, + * timer IRQs will continue to flow through the IOAPIC. + */ + for (i = 0; i < KVM_MAX_VCPUS; ++i) { + vcpu = kvm->vcpus[i]; + if (!vcpu) + continue; + kvm_apic_local_deliver(vcpu, APIC_LVT0); + } } void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu) -- cgit v1.2.3 From 8fdb2351d51b040146f10a624387bbd102d851c0 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Mon, 20 Oct 2008 10:20:02 +0200 Subject: KVM: x86: Fix and refactor NMI watchdog emulation This patch refactors the NMI watchdog delivery patch, consolidating tests and providing a proper API for delivering watchdog events. An included micro-optimization is to check only for apic_hw_enabled in kvm_apic_local_deliver (the test for LVT mask is covering the soft-disabled case already). Signed-off-by: Jan Kiszka Acked-by: Sheng Yang Signed-off-by: Avi Kivity --- arch/x86/kvm/i8254.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) (limited to 'arch/x86/kvm/i8254.c') diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index 580cc1d01c7..b6fcf5a9e50 100644 --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -612,15 +612,18 @@ static void __inject_pit_timer_intr(struct kvm *kvm) mutex_unlock(&kvm->lock); /* - * Provides NMI watchdog support in IOAPIC mode. - * The route is: PIT -> PIC -> LVT0 in NMI mode, - * timer IRQs will continue to flow through the IOAPIC. + * 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. */ for (i = 0; i < KVM_MAX_VCPUS; ++i) { vcpu = kvm->vcpus[i]; - if (!vcpu) - continue; - kvm_apic_local_deliver(vcpu, APIC_LVT0); + if (vcpu) + kvm_apic_nmi_wd_deliver(vcpu); } } -- cgit v1.2.3 From cc6e462cd54e64858ea25816df87d033229efe56 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Mon, 20 Oct 2008 10:20:03 +0200 Subject: KVM: x86: Optimize NMI watchdog delivery 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/kvm/i8254.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'arch/x86/kvm/i8254.c') diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index b6fcf5a9e50..e665d1c623c 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) -- cgit v1.2.3