> -----Original Message----- > From: kvm-owner@xxxxxxxxxxxxxxx [mailto:kvm-owner@xxxxxxxxxxxxxxx] > On Behalf Of Wanpeng Li > Sent: Friday, August 01, 2014 4:12 PM > To: Paolo Bonzini; Jan Kiszka > Cc: Marcelo Tosatti; Gleb Natapov; Bandan Das; Zhang, Yang Z; > kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Wanpeng Li > Subject: [PATCH 2/2] KVM: nVMX: fix acknowledge interrupt on exit when > APICv is in use > > After commit 77b0f5d (KVM: nVMX: Ack and write vector info to intr_info if > L1 asks us to), "Acknowledge interrupt on exit" behavior can be emulated. To > do so, KVM will ask the APIC for the interrupt vector if during a nested > vmexit if VM_EXIT_ACK_INTR_ON_EXIT is set. With APICv, > kvm_get_apic_interrupt would return -1 and give the following WARNING: > > Call Trace: > [<ffffffff81493563>] dump_stack+0x49/0x5e [<ffffffff8103f0eb>] > warn_slowpath_common+0x7c/0x96 [<ffffffffa059709a>] ? > nested_vmx_vmexit+0xa4/0x233 [kvm_intel] [<ffffffff8103f11a>] > warn_slowpath_null+0x15/0x17 [<ffffffffa059709a>] > nested_vmx_vmexit+0xa4/0x233 [kvm_intel] [<ffffffffa0594295>] ? > nested_vmx_exit_handled+0x6a/0x39e [kvm_intel] [<ffffffffa0537931>] ? > kvm_apic_has_interrupt+0x80/0xd5 [kvm] [<ffffffffa05972ec>] > vmx_check_nested_events+0xc3/0xd3 [kvm_intel] [<ffffffffa051ebe9>] > inject_pending_event+0xd0/0x16e [kvm] [<ffffffffa051efa0>] > vcpu_enter_guest+0x319/0x704 [kvm] > > If enabling APIC-v, all interrupts to L1 are delivered through APIC-v. > But when L2 is running, external interrupt will casue L1 vmexit with reason > external interrupt. Then L1 will pick up the interrupt through vmcs12. when > L1 ack the interrupt, since the APIC-v is enabled when > L1 is running, so APIC-v hardware still will do vEOI updating. The problem is > that the interrupt is delivered not through APIC-v hardware, this means > SVI/RVI/vPPR are not setting, but hardware required them when doing vEOI > updating. The solution is that, when L1 tried to pick up the interrupt from > vmcs12, then hypervisor will help to update the SVI/RVI/vPPR to make sure > the following vEOI updating and vPPR updating corrently. > > Also, since interrupt is delivered through vmcs12, so APIC-v hardware will not > cleare vIRR and hypervisor need to clear it before L1 running. > > Suggested-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> > Suggested-by: "Zhang, Yang Z" <yang.z.zhang@xxxxxxxxx> > Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx> Tested-by: Liu, RongrongX <rongrongx.liu@xxxxxxxxx> > --- > arch/x86/kvm/lapic.c | 18 ++++++++++++++++++ arch/x86/kvm/lapic.h | 1 > + > arch/x86/kvm/vmx.c | 10 ++++++++++ > 3 files changed, 29 insertions(+) > > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index > 3855103..06942b9 100644 > --- a/arch/x86/kvm/lapic.c > +++ b/arch/x86/kvm/lapic.c > @@ -534,6 +534,24 @@ static void apic_set_tpr(struct kvm_lapic *apic, u32 > tpr) > apic_update_ppr(apic); > } > > +int kvm_lapic_ack_apicv(struct kvm_vcpu *vcpu) { > + struct kvm_lapic *apic = vcpu->arch.apic; > + int vec; > + > + vec = kvm_apic_has_interrupt(vcpu); > + > + if (vec == -1) > + return vec; > + > + apic_set_vector(vec, apic->regs + APIC_ISR); > + apic_update_ppr(apic); > + apic_clear_vector(vec, apic->regs + APIC_IRR); > + > + return vec; > +} > +EXPORT_SYMBOL_GPL(kvm_lapic_ack_apicv); > + > int kvm_apic_match_physical_addr(struct kvm_lapic *apic, u16 dest) { > return dest == 0xff || kvm_apic_id(apic) == dest; diff --git > a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h index 6a11845..ead1392 > 100644 > --- a/arch/x86/kvm/lapic.h > +++ b/arch/x86/kvm/lapic.h > @@ -169,5 +169,6 @@ static inline bool kvm_apic_has_events(struct > kvm_vcpu *vcpu) } > > bool kvm_apic_pending_eoi(struct kvm_vcpu *vcpu, int vector); > +int kvm_lapic_ack_apicv(struct kvm_vcpu *vcpu); > > #endif > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index > b8122b3..c604f3c 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -8766,6 +8766,16 @@ static void nested_vmx_vmexit(struct kvm_vcpu > *vcpu, u32 exit_reason, > if ((exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT) > && nested_exit_intr_ack_set(vcpu)) { > int irq = kvm_cpu_get_interrupt(vcpu); > + > + if (irq < 0 && kvm_apic_vid_enabled(vcpu->kvm)) { > + irq = kvm_lapic_ack_apicv(vcpu); > + if (irq >= 0) { > + vmx_hwapic_isr_update(vcpu->kvm, irq); > + /* try to update RVI */ > + kvm_make_request(KVM_REQ_EVENT, > vcpu); > + } > + } > + > WARN_ON(irq < 0); > vmcs12->vm_exit_intr_info = irq | > INTR_INFO_VALID_MASK | INTR_TYPE_EXT_INTR; > -- > 1.9.1 > > -- > 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 -- 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
