On 10/14/2011 08:07 PM, Jan Kiszka wrote: > On 2011-10-14 13:59, Sasha Levin wrote: >> On Fri, 2011-10-14 at 17:51 +0800, Lai Jiangshan wrote: >>> Currently, NMI interrupt is blindly sent to all the vCPUs when NMI >>> button event happens. This doesn't properly emulate real hardware on >>> which NMI button event triggers LINT1. Because of this, NMI is sent to >>> the processor even when LINT1 is masked in LVT. For example, this >>> causes the problem that kdump initiated by NMI sometimes doesn't work >>> on KVM, because kdump assumes NMI is masked on CPUs other than CPU0. >>> >>> With this patch, we introduce introduce KVM_SET_LINT1, >>> and we can use KVM_SET_LINT1 to correctly emulate NMI button >>> without change the old KVM_NMI behavior. >>> >>> Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx> >>> Reported-by: Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx> >>> --- >> >> It could use a documentation update as well. >> >>> arch/x86/kvm/irq.h | 1 + >>> arch/x86/kvm/lapic.c | 7 +++++++ >>> arch/x86/kvm/x86.c | 8 ++++++++ >>> include/linux/kvm.h | 3 +++ >>> 4 files changed, 19 insertions(+), 0 deletions(-) >>> diff --git a/arch/x86/kvm/irq.h b/arch/x86/kvm/irq.h >>> index 53e2d08..0c96315 100644 >>> --- a/arch/x86/kvm/irq.h >>> +++ b/arch/x86/kvm/irq.h >>> @@ -95,6 +95,7 @@ void kvm_pic_reset(struct kvm_kpic_state *s); >>> void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu); >>> void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu); >>> void kvm_apic_nmi_wd_deliver(struct kvm_vcpu *vcpu); >>> +void kvm_apic_lint1_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 57dcbd4..87fe36a 100644 >>> --- a/arch/x86/kvm/lapic.c >>> +++ b/arch/x86/kvm/lapic.c >>> @@ -1039,6 +1039,13 @@ void kvm_apic_nmi_wd_deliver(struct kvm_vcpu *vcpu) >>> kvm_apic_local_deliver(apic, APIC_LVT0); >>> } >>> >>> +void kvm_apic_lint1_deliver(struct kvm_vcpu *vcpu) >>> +{ >>> + struct kvm_lapic *apic = vcpu->arch.apic; >>> + >>> + kvm_apic_local_deliver(apic, APIC_LVT1); >>> +} >>> + >>> static struct kvm_timer_ops lapic_timer_ops = { >>> .is_periodic = lapic_is_periodic, >>> }; >>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >>> index 84a28ea..fccd094 100644 >>> --- a/arch/x86/kvm/x86.c >>> +++ b/arch/x86/kvm/x86.c >>> @@ -2077,6 +2077,7 @@ int kvm_dev_ioctl_check_extension(long ext) >>> case KVM_CAP_XSAVE: >>> case KVM_CAP_ASYNC_PF: >>> case KVM_CAP_GET_TSC_KHZ: >>> + case KVM_CAP_SET_LINT1: >>> r = 1; >>> break; >>> case KVM_CAP_COALESCED_MMIO: >>> @@ -3264,6 +3265,13 @@ long kvm_arch_vcpu_ioctl(struct file *filp, >>> >>> goto out; >>> } >>> + case KVM_SET_LINT1: { >>> + r = -EINVAL; >>> + if (!irqchip_in_kernel(vcpu->kvm)) >>> + goto out; >>> + r = 0; >>> + kvm_apic_lint1_deliver(vcpu); >> >> We simply ignore the return value of kvm_apic_local_deliver() and assume >> it always works. why? >> > > Hmm, I suddenly realized that we switched from enhancing the KVM_NMI > IOCTL to adding KVM_SET_LINT1 - what motivated this? Enhancing the KVM_NMI directly fixes the problem and matches the real hard ware more, but it changes API bahavior.(we preferred to this one) >From the previous mails, I found you and Avi prefer to SET_LINT1 which keep old behavior and it is also OK for us. But I found it is hard to be implemented before, and I switched this one when you told me the clue. > > ( Maybe we should let the kernel part settle first before iterating > through user space changes. ) > Yes, you are right, we should settle the kernel-site at first, But I need you and Avi's suggestions. Thanks, Lai -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html