Re: [Qemu-devel] [PATCH 1/6] kvm: encapsulate HAS_DEVICE for vm attrs

[Paolo Bonzini <pbonzini@redhat.com>]

On 12/03/2015 13:53, Jens Freimann wrote:
> From: Dominik Dingel <dingel@linux.vnet.ibm.com>
> 
> More and more virtual machine specifics between kvm and qemu will be
> transferred with vm attributes.
> So we encapsulate the common logic in a generic function.
> 
> Additionally we need only to check during initialization if kvm supports
> virtual machine attributes.
> 
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Suggested-by: Thomas Huth <thuth@linux.vnet.ibm.com>
> Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
> Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
> Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
> ---
>  include/sysemu/kvm.h | 12 ++++++++++++
>  kvm-all.c            | 21 +++++++++++++++++++++
>  2 files changed, 33 insertions(+)
> 
> diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
> index 30cb84d..1fcde16 100644
> --- a/include/sysemu/kvm.h
> +++ b/include/sysemu/kvm.h
> @@ -225,6 +225,18 @@ int kvm_vcpu_ioctl(CPUState *cpu, int type, ...);
>  int kvm_device_ioctl(int fd, int type, ...);
>  
>  /**
> + * kvm_vm_check_attr - check for existence of a specific vm attribute
> + * @s: The KVMState pointer
> + * @group: the group
> + * @attr: the attribute of that group to query for
> + *
> + * Returns: 1 if the attribute exists
> + *          0 if the attribute either does not exist or if the vm device
> + *            interface is unavailable
> + */
> +int kvm_vm_check_attr(KVMState *s, uint32_t group, uint64_t attr);
> +
> +/**
>   * kvm_create_device - create a KVM device for the device control API
>   * @KVMState: The KVMState pointer
>   * @type: The KVM device type (see Documentation/virtual/kvm/devices in the
> diff --git a/kvm-all.c b/kvm-all.c
> index 05a79c2..e1ca8e0 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -126,6 +126,7 @@ bool kvm_gsi_routing_allowed;
>  bool kvm_gsi_direct_mapping;
>  bool kvm_allowed;
>  bool kvm_readonly_mem_allowed;
> +bool kvm_vm_attributes_allowed;
>  
>  static const KVMCapabilityInfo kvm_required_capabilites[] = {
>      KVM_CAP_INFO(USER_MEMORY),
> @@ -1598,6 +1599,9 @@ static int kvm_init(MachineState *ms)
>      kvm_resamplefds_allowed =
>          (kvm_check_extension(s, KVM_CAP_IRQFD_RESAMPLE) > 0);
>  
> +    kvm_vm_attributes_allowed =
> +        (kvm_check_extension(s, KVM_CAP_VM_ATTRIBUTES) > 0);
> +
>      ret = kvm_arch_init(s);
>      if (ret < 0) {
>          goto err;
> @@ -1936,6 +1940,23 @@ int kvm_device_ioctl(int fd, int type, ...)
>      return ret;
>  }
>  
> +int kvm_vm_check_attr(KVMState *s, uint32_t group, uint64_t attr)
> +{
> +    int ret;
> +    struct kvm_device_attr attribute = {
> +        .group = group,
> +        .attr = attr,
> +    };
> +
> +    if (!kvm_vm_attributes_allowed) {
> +        return 0;
> +    }
> +
> +    ret = kvm_vm_ioctl(s, KVM_HAS_DEVICE_ATTR, &attribute);
> +    /* kvm returns 0 on success for HAS_DEVICE_ATTR */
> +    return ret ? 0 : 1;
> +}
> +
>  int kvm_has_sync_mmu(void)
>  {
>      return kvm_check_extension(kvm_state, KVM_CAP_SYNC_MMU);
> 

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