Re: [PATCH v2 2/3] KVM: nVMX: Ack and write vector info to intr_info if L1 asks us to

[Marcelo Tosatti <mtosatti@redhat.com>]

On Mon, Mar 31, 2014 at 05:00:24PM -0400, Bandan Das wrote:
> This feature emulates the "Acknowledge interrupt on exit" behavior.
> We can safely emulate it for L1 to run L2 even if L0 itself has it
> disabled (to run L1).
> 
> Signed-off-by: Bandan Das <bsd@redhat.com>
> ---
>  arch/x86/kvm/irq.c |  1 +
>  arch/x86/kvm/vmx.c | 19 +++++++++++++++++++
>  2 files changed, 20 insertions(+)
> 
> diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c
> index 484bc87..bd0da43 100644
> --- a/arch/x86/kvm/irq.c
> +++ b/arch/x86/kvm/irq.c
> @@ -113,6 +113,7 @@ int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
>  
>  	return kvm_get_apic_interrupt(v);	/* APIC */
>  }
> +EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
>  
>  void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
>  {
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 3e7f60c..bdc8f2d 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -4489,6 +4489,18 @@ static bool nested_exit_on_intr(struct kvm_vcpu *vcpu)
>  		PIN_BASED_EXT_INTR_MASK;
>  }
>  
> +/*
> + * In nested virtualization, check if L1 has enabled
> + * interrupt acknowledgement that writes the interrupt vector
> + * info on vmexit
> + * 
> + */
> +static bool nested_exit_intr_ack_set(struct kvm_vcpu *vcpu)
> +{
> +	return get_vmcs12(vcpu)->vm_exit_controls &
> +		VM_EXIT_ACK_INTR_ON_EXIT;
> +}
> +
>  static bool nested_exit_on_nmi(struct kvm_vcpu *vcpu)
>  {
>  	return get_vmcs12(vcpu)->pin_based_vm_exec_control &
> @@ -8442,6 +8454,13 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
>  	prepare_vmcs12(vcpu, vmcs12, exit_reason, exit_intr_info,
>  		       exit_qualification);
>  
> +	if ((exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT)
> +	    && nested_exit_intr_ack_set(vcpu)) {
> +		int irq = kvm_cpu_get_interrupt(vcpu);

Can irq be -1 ?

> +		vmcs12->vm_exit_intr_info = irq |
> +			INTR_INFO_VALID_MASK | INTR_TYPE_EXT_INTR;
> +	}
> +
>  	trace_kvm_nested_vmexit_inject(vmcs12->vm_exit_reason,
>  				       vmcs12->exit_qualification,
>  				       vmcs12->idt_vectoring_info_field,
> -- 
> 1.8.3.1
> 
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