[PATCH 2/3] KVM: uapi: Remove KVM_DEV_TYPE_ARM_PV_TIME in kvm_device_type
Steven Price
steven.price at arm.com
Mon Aug 17 05:49:12 EDT 2020
On 17/08/2020 09:43, zhukeqian wrote:
> Hi Marc,
>
> On 2020/8/17 15:39, Marc Zyngier wrote:
>> On 2020-08-17 04:37, Keqian Zhu wrote:
>>> ARM64 PV-time ST is configured by userspace through vCPU attribute,
>>> and KVM_DEV_TYPE_ARM_PV_TIME is unused.
>>>
>>> Signed-off-by: Keqian Zhu <zhukeqian1 at huawei.com>
>>> ---
>>> include/uapi/linux/kvm.h | 2 --
>>> tools/include/uapi/linux/kvm.h | 2 --
>>> 2 files changed, 4 deletions(-)
>>>
>>> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
>>> index 4fdf303..9a6b97e 100644
>>> --- a/include/uapi/linux/kvm.h
>>> +++ b/include/uapi/linux/kvm.h
>>> @@ -1258,8 +1258,6 @@ enum kvm_device_type {
>>> #define KVM_DEV_TYPE_ARM_VGIC_ITS KVM_DEV_TYPE_ARM_VGIC_ITS
>>> KVM_DEV_TYPE_XIVE,
>>> #define KVM_DEV_TYPE_XIVE KVM_DEV_TYPE_XIVE
>>> - KVM_DEV_TYPE_ARM_PV_TIME,
>>> -#define KVM_DEV_TYPE_ARM_PV_TIME KVM_DEV_TYPE_ARM_PV_TIME
>>> KVM_DEV_TYPE_MAX,
>>> };
>>>
>>> diff --git a/tools/include/uapi/linux/kvm.h b/tools/include/uapi/linux/kvm.h
>>> index 4fdf303..9a6b97e 100644
>>> --- a/tools/include/uapi/linux/kvm.h
>>> +++ b/tools/include/uapi/linux/kvm.h
>>> @@ -1258,8 +1258,6 @@ enum kvm_device_type {
>>> #define KVM_DEV_TYPE_ARM_VGIC_ITS KVM_DEV_TYPE_ARM_VGIC_ITS
>>> KVM_DEV_TYPE_XIVE,
>>> #define KVM_DEV_TYPE_XIVE KVM_DEV_TYPE_XIVE
>>> - KVM_DEV_TYPE_ARM_PV_TIME,
>>> -#define KVM_DEV_TYPE_ARM_PV_TIME KVM_DEV_TYPE_ARM_PV_TIME
>>> KVM_DEV_TYPE_MAX,
>>> };
>>
>> No. You can't drop anything from UAPI, used or not. Doing so will
>> break the compilation of any userspace that, for any reason, references
>> this value. We cannot reuse this value in the future either, as it would
>> create a we wouldn't know which device to create.
>>
>> It is pretty unfortunate that PV time has turned into such a train wreck,
>> but that's what we have now, and it has to stay.
> Well, I see. It is a sad thing indeed.
Sorry about that, this got refactored so many times I guess I lost track
of what was actually needed and this hunk remained when it should have
been removed.
I would hope that I'm the only one who has any userspace code which uses
this, but I guess we should still be cautious since this has been in
several releases now.
Steve
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