Re: [Qemu-devel] [PATCH v10 01/18] Add kvm_eventfds_enabled function

[Paolo Bonzini <pbonzini@redhat.com>]

Il 27/05/2014 14:03, Nikolay Nikolaev ha scritto:
> Add a function to check if the eventfd capability is present in KVM in
> the host kernel.
>
> Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
> Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
> ---
>  include/sysemu/kvm.h |   11 +++++++++++
>  kvm-all.c            |    4 ++++
>  kvm-stub.c           |    1 +
>  3 files changed, 16 insertions(+)
>
> diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
> index e7ad9d1..1c7f5f6 100644
> --- a/include/sysemu/kvm.h
> +++ b/include/sysemu/kvm.h
> @@ -43,6 +43,7 @@ extern bool kvm_allowed;
>  extern bool kvm_kernel_irqchip;
>  extern bool kvm_async_interrupts_allowed;
>  extern bool kvm_halt_in_kernel_allowed;
> +extern bool kvm_eventfds_allowed;
>  extern bool kvm_irqfds_allowed;
>  extern bool kvm_msi_via_irqfd_allowed;
>  extern bool kvm_gsi_routing_allowed;
> @@ -83,6 +84,15 @@ extern bool kvm_readonly_mem_allowed;
>  #define kvm_halt_in_kernel() (kvm_halt_in_kernel_allowed)
>
>  /**
> + * kvm_eventfds_enabled:
> + *
> + * Returns: true if we can use eventfds to receive notifications
> + * from a KVM CPU (ie the kernel supports eventds and we are running
> + * with a configuration where it is meaningful to use them).
> + */
> +#define kvm_eventfds_enabled() (kvm_eventfds_allowed)
> +
> +/**
>   * kvm_irqfds_enabled:
>   *
>   * Returns: true if we can use irqfds to inject interrupts into
> @@ -128,6 +138,7 @@ extern bool kvm_readonly_mem_allowed;
>  #define kvm_irqchip_in_kernel() (false)
>  #define kvm_async_interrupts_enabled() (false)
>  #define kvm_halt_in_kernel() (false)
> +#define kvm_eventfds_enabled() (false)
>  #define kvm_irqfds_enabled() (false)
>  #define kvm_msi_via_irqfd_enabled() (false)
>  #define kvm_gsi_routing_allowed() (false)
> diff --git a/kvm-all.c b/kvm-all.c
> index a343ede..9649cd3 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -112,6 +112,7 @@ KVMState *kvm_state;
>  bool kvm_kernel_irqchip;
>  bool kvm_async_interrupts_allowed;
>  bool kvm_halt_in_kernel_allowed;
> +bool kvm_eventfds_allowed;
>  bool kvm_irqfds_allowed;
>  bool kvm_msi_via_irqfd_allowed;
>  bool kvm_gsi_routing_allowed;
> @@ -1504,6 +1505,9 @@ int kvm_init(MachineClass *mc)
>          (kvm_check_extension(s, KVM_CAP_READONLY_MEM) > 0);
>  #endif
>
> +    kvm_eventfds_allowed =
> +        (kvm_check_extension(s, KVM_CAP_IOEVENTFD) > 0);
> +
>      ret = kvm_arch_init(s);
>      if (ret < 0) {
>          goto err;
> diff --git a/kvm-stub.c b/kvm-stub.c
> index 8acda86..3fb17f2 100644
> --- a/kvm-stub.c
> +++ b/kvm-stub.c
> @@ -22,6 +22,7 @@
>  KVMState *kvm_state;
>  bool kvm_kernel_irqchip;
>  bool kvm_async_interrupts_allowed;
> +bool kvm_eventfds_allowed;
>  bool kvm_irqfds_allowed;
>  bool kvm_msi_via_irqfd_allowed;
>  bool kvm_gsi_routing_allowed;
>

Acked-by: Paolo Bonzini <pbonzini@redhat.com>