On 04.01.2012, at 11:33, Avi Kivity <[email protected]> wrote:
> On 01/03/2012 04:13 PM, Alexander Graf wrote:
>> On 03.01.2012, at 15:01, Avi Kivity wrote:
>>
>>> On 12/31/2011 08:16 AM, Liu Yu wrote:
>>>> Add a new field opt_feature in struct kvm_ppc_pvinfo
>>>> to tell userspace whether it support hcall idle.
>>>>
>>>> diff --git a/include/linux/kvm.h b/include/linux/kvm.h
>>>> index c107fae..5af21f3 100644
>>>> --- a/include/linux/kvm.h
>>>> +++ b/include/linux/kvm.h
>>>> @@ -426,9 +426,12 @@ struct kvm_ppc_pvinfo {
>>>> /* out */
>>>> __u32 flags;
>>>> __u32 hcall[4];
>>>> - __u8 pad[108];
>>>> + __u32 opt_features;
>>>> + __u8 pad[104];
>>>> };
>>>>
>>>> +#define KVM_PPC_PVINFO_HAS_EV_IDLE (1<<0)
>>>> +
>>>>
>>>
>>> Needs to be documented, plus a KVM_CAP so userspace can discover that
>>> this feature is available,
>>
>> Not if we put the bit into flags. Then user space can just check the flags
>> bitmap and know that it's there regardless of capabilities, because older
>> kernels will set the bit to 0.
>
> It needs to detect that opt_features is available during compile time
> (qemu copies headers, but we don't want to force everyone to do that).
The point is that we don't need opt_features. We already have a fearure bitmap
in the struct.
Alex
--
To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
