Re: [PATCH v5 5/5] KVM : VMX: Use posted interrupt to deliver virtual interrupt

[Gleb Natapov <gleb@redhat.com>]

On Fri, Mar 08, 2013 at 09:23:21AM +0800, Yang Zhang wrote:
> From: Yang Zhang <yang.z.zhang@Intel.com>
> 
> If posted interrupt is avaliable, then uses it to inject virtual
> interrupt to guest.
> 
> Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
> ---
>  arch/x86/kvm/irq.c   |    2 +-
>  arch/x86/kvm/lapic.c |   16 +++++++++++++---
>  arch/x86/kvm/lapic.h |    1 +
>  arch/x86/kvm/x86.c   |    4 ++++
>  4 files changed, 19 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c
> index 484bc87..93b1fd0 100644
> --- a/arch/x86/kvm/irq.c
> +++ b/arch/x86/kvm/irq.c
> @@ -81,7 +81,7 @@ int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
>  	if (kvm_cpu_has_extint(v))
>  		return 1;
>  
> -	return kvm_apic_has_interrupt(v) != -1;	/* LAPIC */
> +	return (kvm_apic_has_interrupt(v) != -1) || kvm_hwapic_has_interrupt(v);
>  }
>  EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
>  
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index b3ea50e..76c8df4 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -713,7 +713,10 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
>  		} else
>  			apic_clear_vector(vector, apic->regs + APIC_TMR);
>  
So we still touch apic page to update APIC_TMR register while vcpu is in
non-root mode. SDM seams to prohibit it. Can we get clarification about
how it suppose to work? May it cause any problems in practice?

> -		result = !apic_test_and_set_irr(vector, apic);
> +		result = 1;
> +		if (!kvm_x86_ops->deliver_posted_interrupt(vcpu, vector))
> +			result = !apic_test_and_set_irr(vector, apic);
> +
>  		trace_kvm_apic_accept_irq(vcpu->vcpu_id, delivery_mode,
>  					  trig_mode, vector, !result);
>  		if (!result) {
> @@ -723,8 +726,10 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
>  			break;
>  		}
>  
> -		kvm_make_request(KVM_REQ_EVENT, vcpu);
> -		kvm_vcpu_kick(vcpu);
> +		if (!kvm_x86_ops->vm_has_apicv(vcpu->kvm)) {
> +			kvm_make_request(KVM_REQ_EVENT, vcpu);
> +			kvm_vcpu_kick(vcpu);
> +		}
>  		break;
>  
>  	case APIC_DM_REMRD:
> @@ -1604,6 +1609,11 @@ int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu)
>  	return highest_irr;
>  }
>  
> +bool kvm_hwapic_has_interrupt(struct kvm_vcpu *vcpu)
> +{
> +	return kvm_x86_ops->sync_pir_to_irr(vcpu, false);
> +}
> +
>  int kvm_apic_accept_pic_intr(struct kvm_vcpu *vcpu)
>  {
>  	u32 lvt0 = kvm_apic_get_reg(vcpu->arch.apic, APIC_LVT0);
> diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
> index e5327be..c6abc63 100644
> --- a/arch/x86/kvm/lapic.h
> +++ b/arch/x86/kvm/lapic.h
> @@ -37,6 +37,7 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu);
>  void kvm_free_lapic(struct kvm_vcpu *vcpu);
>  
>  int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu);
> +bool kvm_hwapic_has_interrupt(struct kvm_vcpu *vcpu);
>  int kvm_apic_accept_pic_intr(struct kvm_vcpu *vcpu);
>  int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu);
>  void kvm_lapic_reset(struct kvm_vcpu *vcpu);
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 0baa90d..57f8570 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -2679,6 +2679,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
>  static int kvm_vcpu_ioctl_get_lapic(struct kvm_vcpu *vcpu,
>  				    struct kvm_lapic_state *s)
>  {
> +	kvm_x86_ops->sync_pir_to_irr(vcpu, true);
>  	memcpy(s->regs, vcpu->arch.apic->regs, sizeof *s);
>  
>  	return 0;
> @@ -5699,6 +5700,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
>  	}
>  
>  	if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win) {
> +		kvm_x86_ops->sync_pir_to_irr(vcpu, true);
>  		inject_pending_event(vcpu);
>  
>  		/* enable NMI/IRQ window open exits if needed */
> @@ -5741,6 +5743,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
>  
>  	local_irq_disable();
>  
> +	kvm_x86_ops->posted_intr_clear_on(vcpu);
> +
>  	if (vcpu->mode == EXITING_GUEST_MODE || vcpu->requests
>  	    || need_resched() || signal_pending(current)) {
>  		vcpu->mode = OUTSIDE_GUEST_MODE;
> -- 
> 1.7.1

--
			Gleb.