Re: [Qemu-devel] [PATCH] KVM_CAP_IRQFD and KVM_CAP_IRQFD_RESAMPLE checks

[Paolo Bonzini <pbonzini@redhat.com>]

Il 29/08/2014 19:38, Eric Auger ha scritto:
> Compute kvm_irqfds_allowed by checking the KVM_CAP_IRQFD extension.
> Remove direct settings in architecture specific files.
> 
> Add a new kvm_resamplefds_allowed variable, initialized by
> checking the KVM_CAP_IRQFD_RESAMPLE extension. Add a corresponding
> kvm_resamplefds_enabled() function.

Please add a user too (in hw/misc/vfio.c).

Otherwise looks good, thanks!

Paolo

> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> 
> ---
> 
> in practice KVM_CAP_IRQFD_RESAMPLE seems to be always enabled
> as soon as kernel has HAVE_KVM_IRQFD so the resamplefd check
> may be unnecessary.
> ---
>  hw/intc/openpic_kvm.c |  1 -
>  hw/intc/xics_kvm.c    |  1 -
>  include/sysemu/kvm.h  | 10 ++++++++++
>  kvm-all.c             |  7 +++++++
>  target-i386/kvm.c     |  1 -
>  target-s390x/kvm.c    |  1 -
>  6 files changed, 17 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/intc/openpic_kvm.c b/hw/intc/openpic_kvm.c
> index e3bce04..6cef3b1 100644
> --- a/hw/intc/openpic_kvm.c
> +++ b/hw/intc/openpic_kvm.c
> @@ -229,7 +229,6 @@ static void kvm_openpic_realize(DeviceState *dev, Error **errp)
>          kvm_irqchip_add_irq_route(kvm_state, i, 0, i);
>      }
>  
> -    kvm_irqfds_allowed = true;
>      kvm_msi_via_irqfd_allowed = true;
>      kvm_gsi_routing_allowed = true;
>  
> diff --git a/hw/intc/xics_kvm.c b/hw/intc/xics_kvm.c
> index 20b19e9..c15453f 100644
> --- a/hw/intc/xics_kvm.c
> +++ b/hw/intc/xics_kvm.c
> @@ -448,7 +448,6 @@ static void xics_kvm_realize(DeviceState *dev, Error **errp)
>      }
>  
>      kvm_kernel_irqchip = true;
> -    kvm_irqfds_allowed = true;
>      kvm_msi_via_irqfd_allowed = true;
>      kvm_gsi_direct_mapping = true;
>  
> diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
> index 174ea36..69c4d0f 100644
> --- a/include/sysemu/kvm.h
> +++ b/include/sysemu/kvm.h
> @@ -45,6 +45,7 @@ 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_resamplefds_allowed;
>  extern bool kvm_msi_via_irqfd_allowed;
>  extern bool kvm_gsi_routing_allowed;
>  extern bool kvm_gsi_direct_mapping;
> @@ -102,6 +103,15 @@ extern bool kvm_readonly_mem_allowed;
>  #define kvm_irqfds_enabled() (kvm_irqfds_allowed)
>  
>  /**
> + * kvm_resamplefds_enabled:
> + *
> + * Returns: true if we can use resamplefds to inject interrupts into
> + * a KVM CPU (ie the kernel supports resamplefds and we are running
> + * with a configuration where it is meaningful to use them).
> + */
> +#define kvm_resamplefds_enabled() (kvm_resamplefds_allowed)
> +
> +/**
>   * kvm_msi_via_irqfd_enabled:
>   *
>   * Returns: true if we can route a PCI MSI (Message Signaled Interrupt)
> diff --git a/kvm-all.c b/kvm-all.c
> index 1402f4f..fdc97d6 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -116,6 +116,7 @@ bool kvm_async_interrupts_allowed;
>  bool kvm_halt_in_kernel_allowed;
>  bool kvm_eventfds_allowed;
>  bool kvm_irqfds_allowed;
> +bool kvm_resamplefds_allowed;
>  bool kvm_msi_via_irqfd_allowed;
>  bool kvm_gsi_routing_allowed;
>  bool kvm_gsi_direct_mapping;
> @@ -1548,6 +1549,12 @@ int kvm_init(MachineClass *mc)
>      kvm_eventfds_allowed =
>          (kvm_check_extension(s, KVM_CAP_IOEVENTFD) > 0);
>  
> +    kvm_irqfds_allowed =
> +        (kvm_check_extension(s, KVM_CAP_IRQFD) > 0);
> +
> +    kvm_resamplefds_allowed =
> +        (kvm_check_extension(s, KVM_CAP_IRQFD_RESAMPLE) > 0);
> +
>      ret = kvm_arch_init(s);
>      if (ret < 0) {
>          goto err;
> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> index 097fe11..4bc2d80 100644
> --- a/target-i386/kvm.c
> +++ b/target-i386/kvm.c
> @@ -2447,7 +2447,6 @@ void kvm_arch_init_irq_routing(KVMState *s)
>       * irqchip, so we can use irqfds, and on x86 we know
>       * we can use msi via irqfd and GSI routing.
>       */
> -    kvm_irqfds_allowed = true;
>      kvm_msi_via_irqfd_allowed = true;
>      kvm_gsi_routing_allowed = true;
>  }
> diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
> index a32d91a..4d2bca6 100644
> --- a/target-s390x/kvm.c
> +++ b/target-s390x/kvm.c
> @@ -1281,7 +1281,6 @@ void kvm_arch_init_irq_routing(KVMState *s)
>       * have to override the common code kvm_halt_in_kernel_allowed setting.
>       */
>      if (kvm_check_extension(s, KVM_CAP_IRQ_ROUTING)) {
> -        kvm_irqfds_allowed = true;
>          kvm_gsi_routing_allowed = true;
>          kvm_halt_in_kernel_allowed = false;
>      }
>