Subject: [PATCH v7 2/4] KVM: introduce kvm_arch_intc_initialized and use it in irqfd

From: [email-masked] (André Przywara)
Date: Fri, 16 Jan 2015 09:35:39 +0000

Hi Eric,

On 01/15/2015 02:47 PM, Eric Auger wrote:
> Introduce __KVM_HAVE_ARCH_INTC_INITIALIZED define and
> associated kvm_arch_intc_initialized function. This latter
> allows to test whether the virtual interrupt controller is initialized
> and ready to accept virtual IRQ injection. On some architectures,
> the virtual interrupt controller is dynamically instantiated, justifying
> that kind of check.
> 
> The new function can now be used by irqfd to check whether the
> virtual interrupt controller is ready on KVM_IRQFD request. If not,
> KVM_IRQFD returns -EAGAIN.
> 
> Signed-off-by: Eric Auger <[email-masked]>
> Acked-by: Christoffer Dall <[email-masked]>
> 
> ---
> v6 -> v7:
> - From now on, kvm_irqfd_assign calls kvm_arch_intc_initialized
>   (previously introduced in subsequent patch file).
> - add Christoffer's ack
> 
> v5 -> v6:
> - rename function name and macro
> - add kvm_arch_intc_initialized declaration in case the archi defines
>   the macro
> ---
>  include/linux/kvm_host.h | 14 ++++++++++++++
>  virt/kvm/eventfd.c       |  3 +++
>  2 files changed, 17 insertions(+)
> 
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 26f1060..702036a 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -706,6 +706,20 @@ static inline wait_queue_head_t *kvm_arch_vcpu_wq(struct kvm_vcpu *vcpu)
>  #endif
>  }
>  
> +#ifdef __KVM_HAVE_ARCH_INTC_INITIALIZED
> +/*
> + * returns trues if the virtual interrupt controller is initialized and

Nit:          true

Other than that:
Reviewed-by: Andre Przywara <[email-masked]>

Cheers,
Andre.

> + * ready to accept virtual IRQ. On some architectures the virtual interrupt
> + * controller is dynamically instantiated and this is not always true.
> + */
> +bool kvm_arch_intc_initialized(struct kvm *kvm);
> +#else
> +static inline bool kvm_arch_intc_initialized(struct kvm *kvm)
> +{
> +	return true;
> +}
> +#endif
> +
>  int kvm_arch_init_vm(struct kvm *kvm, unsigned long type);
>  void kvm_arch_destroy_vm(struct kvm *kvm);
>  void kvm_arch_sync_events(struct kvm *kvm);
> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
> index 148b239..fc5f43e 100644
> --- a/virt/kvm/eventfd.c
> +++ b/virt/kvm/eventfd.c
> @@ -311,6 +311,9 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
>  	unsigned int events;
>  	int idx;
>  
> +	if (!kvm_arch_intc_initialized(kvm))
> +		return -EAGAIN;
> +
>  	irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL);
>  	if (!irqfd)
>  		return -ENOMEM;
>