Re: [Qemu-devel] [PATCH 3/3] KVM: use KVM_CAP_MAX_VCPU_ID

[David Gibson <david@gibson.dropbear.id.au>]

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On Thu, May 26, 2016 at 10:02:23AM +0200, Greg Kurz wrote:
> As stated in linux/Documentation/virtual/kvm/api.txt:
> 
> The maximum possible value for max_vcpu_id can be retrieved using the
> KVM_CAP_MAX_VCPU_ID of the KVM_CHECK_EXTENSION ioctl() at run-time.
> 
> If the KVM_CAP_MAX_VCPU_ID does not exist, you should assume that
> max_vcpu_id is the same as the value returned from KVM_CAP_MAX_VCPUS.
> 
> Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  kvm-all.c |    8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/kvm-all.c b/kvm-all.c
> index e56f38527815..e74e0c6e2352 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -1459,10 +1459,16 @@ static int kvm_max_vcpus(KVMState *s)
>      return (ret) ? ret : kvm_recommended_vcpus(s);
>  }
>  
> +static int kvm_max_vcpu_id(KVMState *s)
> +{
> +    int ret = kvm_check_extension(s, KVM_CAP_MAX_VCPU_ID);
> +    return (ret) ? ret : kvm_max_vcpus(s);
> +}
> +
>  bool kvm_vcpu_id_is_valid(int vcpu_id)
>  {
>      KVMState *s = KVM_STATE(current_machine->accelerator);
> -    return vcpu_id >= 0 && vcpu_id < kvm_max_vcpus(s);
> +    return vcpu_id >= 0 && vcpu_id < kvm_max_vcpu_id(s);
>  }
>  
>  static int kvm_init(MachineState *ms)
> 

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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