Re: Enable IRQ windows after exception injection if there are pending virq

[Gleb Natapov <gleb@redhat.com>]

On Tue, May 12, 2009 at 11:06:39PM +0800, Dong, Eddie wrote:
> 
> I didn't take many test since our PTS system stop working now due to KVM userspace
> build changes. But since the logic is pretty simple, so I want to post here to see comments.
> Thx, eddie
> 
> 
> 
> 
> If there is pending irq after an virtual exception is injected,
> KVM needs to enable IRQ window to trap back earlier once 
> the exception is handled.
> 
I already posted patch to do that http://patchwork.kernel.org/patch/21830/
Is you patch different?

> Signed-off-by: Eddie Dong <eddie.dong@intel.com>
> 
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 308d8e9..f8ceaea 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -3154,15 +3154,18 @@ static void inject_irq(struct kvm_vcpu *vcpu)
>  	}
>  }
>  
> -static void inject_pending_irq(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
> +static void inject_pending_irq(struct kvm_vcpu *vcpu)
>  {
> -	bool req_int_win = !irqchip_in_kernel(vcpu->kvm) &&
> -		kvm_run->request_interrupt_window;
> -
>  	if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
>  		kvm_x86_ops->drop_interrupt_shadow(vcpu);
>  
>  	inject_irq(vcpu);
> +}
> +
> +static void set_pending_virq(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
> +{
> +	bool req_int_win = !irqchip_in_kernel(vcpu->kvm) &&
> +		kvm_run->request_interrupt_window;
>  
>  	/* enable NMI/IRQ window open exits if needed */
>  	if (vcpu->arch.nmi_pending)
> @@ -3229,7 +3232,9 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
>  	if (vcpu->arch.exception.pending)
>  		__queue_exception(vcpu);
>  	else
> -		inject_pending_irq(vcpu, kvm_run);
> +		inject_pending_irq(vcpu);
> +
> +	set_pending_virq(vcpu, kvm_run);
>  
>  	if (kvm_lapic_enabled(vcpu)) {
>  		if (!vcpu->arch.apic->vapic_addr)


--
			Gleb.