Re: [kvm-devel] [patch 2/4] QEMU/KVM: get/set mpstate libkvm interface

[Avi K. <av...@qu...>]

Marcelo Tosatti wrote:
> Add libkvm interface to get/set the mpstate.
>
> Signed-off-by: Marcelo Tosatti <mto...@re...>
>
> Index: marcelo/git/kvm-userspace.io/libkvm/libkvm.c
> ===================================================================
> --- marcelo.orig/git/kvm-userspace.io/libkvm/libkvm.c
> +++ marcelo/git/kvm-userspace.io/libkvm/libkvm.c
> @@ -776,6 +776,32 @@ int kvm_set_sregs(kvm_context_t kvm, int
>      return ioctl(kvm->vcpu_fd[vcpu], KVM_SET_SREGS, sregs);
>  }
>  
> +int kvm_get_mpstate(kvm_context_t kvm, int vcpu, int *mpstate)
> +{
> +    int r;
> +
> +#ifdef KVM_CAP_MP_STATE
> +    r = ioctl(kvm->fd, KVM_CHECK_EXTENSION, KVM_CAP_MP_STATE);
> +    if (r > 0)
> +        return ioctl(kvm->vcpu_fd[vcpu], KVM_GET_MP_STATE, mpstate);
> +#endif
> +    return -1;
> +}
>   

We usually follow the convention of returning -errno in case of error 
instead of -1 in libkvm.

-- 
Any sufficiently difficult bug is indistinguishable from a feature.