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

From: André Przywara
Date: Fri Jan 16 2015 - 04:35:49 EST


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 <eric.auger@xxxxxxxxxx>
> Acked-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
>
> ---
> 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 <andre.przywara@xxxxxxx>

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;
>

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