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/lapic.c | 34 +++++++++++++++++++++++++++++----- 1 file changed, 29 insertions(+), 5 deletions(-) (limited to 'arch/x86/kvm/lapic.c') diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 0fc3cab4894..206cc11a1c9 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -380,6 +380,14 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode, } break; + case APIC_DM_EXTINT: + /* + * Should only be called by kvm_apic_local_deliver() with LVT0, + * before NMI watchdog was enabled. Already handled by + * kvm_apic_accept_pic_intr(). + */ + break; + default: printk(KERN_ERR "TODO: unsupported delivery mode %x\n", delivery_mode); @@ -743,10 +751,13 @@ static void apic_mmio_write(struct kvm_io_device *this, apic_set_reg(apic, APIC_ICR2, val & 0xff000000); 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); case APIC_LVTT: case APIC_LVTTHMR: case APIC_LVTPC: - case APIC_LVT0: case APIC_LVT1: case APIC_LVTERR: /* TODO: Check vector */ @@ -961,12 +972,25 @@ int apic_has_pending_timer(struct kvm_vcpu *vcpu) return 0; } -static int __inject_apic_timer_irq(struct kvm_lapic *apic) +int kvm_apic_local_deliver(struct kvm_vcpu *vcpu, int lvt_type) { - int vector; + struct kvm_lapic *apic = vcpu->arch.apic; + int vector, mode, trig_mode; + u32 reg; + + if (apic && apic_enabled(apic)) { + reg = apic_get_reg(apic, lvt_type); + vector = reg & APIC_VECTOR_MASK; + mode = reg & APIC_MODE_MASK; + trig_mode = reg & APIC_LVT_LEVEL_TRIGGER; + return __apic_accept_irq(apic, mode, vector, 1, trig_mode); + } + return 0; +} - vector = apic_lvt_vector(apic, APIC_LVTT); - return __apic_accept_irq(apic, APIC_DM_FIXED, vector, 1, 0); +static inline int __inject_apic_timer_irq(struct kvm_lapic *apic) +{ + return kvm_apic_local_deliver(apic->vcpu, APIC_LVTT); } static enum hrtimer_restart apic_timer_fn(struct hrtimer *data) -- cgit v1.2.3-70-g09d2 From 26df99c6c5807115f06d4e1abae397b7f5f3e00c Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Fri, 26 Sep 2008 09:30:54 +0200 Subject: KVM: Kick NMI receiving VCPU Kick the NMI receiving VCPU in case the triggering caller runs in a different context. Signed-off-by: Jan Kiszka Signed-off-by: Avi Kivity --- arch/x86/kvm/lapic.c | 1 + virt/kvm/ioapic.c | 1 + 2 files changed, 2 insertions(+) (limited to 'arch/x86/kvm/lapic.c') diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 206cc11a1c9..304f9ddbdd5 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -354,6 +354,7 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode, case APIC_DM_NMI: kvm_inject_nmi(vcpu); + kvm_vcpu_kick(vcpu); break; case APIC_DM_INIT: diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c index 53772bb4632..c8f939c5507 100644 --- a/virt/kvm/ioapic.c +++ b/virt/kvm/ioapic.c @@ -150,6 +150,7 @@ static int ioapic_inj_irq(struct kvm_ioapic *ioapic, static void ioapic_inj_nmi(struct kvm_vcpu *vcpu) { kvm_inject_nmi(vcpu); + kvm_vcpu_kick(vcpu); } static u32 ioapic_get_delivery_bitmask(struct kvm_ioapic *ioapic, u8 dest, -- cgit v1.2.3-70-g09d2 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 +++++++++------ arch/x86/kvm/irq.h | 2 +- arch/x86/kvm/lapic.c | 20 ++++++++++---------- 3 files changed, 20 insertions(+), 17 deletions(-) (limited to 'arch/x86/kvm/lapic.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); } } diff --git a/arch/x86/kvm/irq.h b/arch/x86/kvm/irq.h index 71e37a530cf..b9e9051650e 100644 --- a/arch/x86/kvm/irq.h +++ b/arch/x86/kvm/irq.h @@ -87,7 +87,7 @@ void kvm_pic_reset(struct kvm_kpic_state *s); void kvm_timer_intr_post(struct kvm_vcpu *vcpu, int vec); void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu); void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu); -int kvm_apic_local_deliver(struct kvm_vcpu *vcpu, int lvt_type); +void kvm_apic_nmi_wd_deliver(struct kvm_vcpu *vcpu); void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu); void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu); void __kvm_migrate_timers(struct kvm_vcpu *vcpu); diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 304f9ddbdd5..0b0d413f0af 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -973,14 +973,12 @@ int apic_has_pending_timer(struct kvm_vcpu *vcpu) return 0; } -int kvm_apic_local_deliver(struct kvm_vcpu *vcpu, int lvt_type) +static int kvm_apic_local_deliver(struct kvm_lapic *apic, int lvt_type) { - struct kvm_lapic *apic = vcpu->arch.apic; + u32 reg = apic_get_reg(apic, lvt_type); int vector, mode, trig_mode; - u32 reg; - if (apic && apic_enabled(apic)) { - reg = apic_get_reg(apic, lvt_type); + if (apic_hw_enabled(apic) && !(reg & APIC_LVT_MASKED)) { vector = reg & APIC_VECTOR_MASK; mode = reg & APIC_MODE_MASK; trig_mode = reg & APIC_LVT_LEVEL_TRIGGER; @@ -989,9 +987,12 @@ int kvm_apic_local_deliver(struct kvm_vcpu *vcpu, int lvt_type) return 0; } -static inline int __inject_apic_timer_irq(struct kvm_lapic *apic) +void kvm_apic_nmi_wd_deliver(struct kvm_vcpu *vcpu) { - return kvm_apic_local_deliver(apic->vcpu, APIC_LVTT); + struct kvm_lapic *apic = vcpu->arch.apic; + + if (apic) + kvm_apic_local_deliver(apic, APIC_LVT0); } static enum hrtimer_restart apic_timer_fn(struct hrtimer *data) @@ -1086,9 +1087,8 @@ void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu) { struct kvm_lapic *apic = vcpu->arch.apic; - if (apic && apic_lvt_enabled(apic, APIC_LVTT) && - atomic_read(&apic->timer.pending) > 0) { - if (__inject_apic_timer_irq(apic)) + if (apic && atomic_read(&apic->timer.pending) > 0) { + if (kvm_apic_local_deliver(apic, APIC_LVTT)) atomic_dec(&apic->timer.pending); } } -- cgit v1.2.3-70-g09d2 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/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(-) (limited to 'arch/x86/kvm/lapic.c') diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 59c3ae10de6..09e6c56572c 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 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) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 0b0d413f0af..afac68c0815 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: -- cgit v1.2.3-70-g09d2