RE: [RFC PATCH v3 4/6] psci: Add hvc call service for ptp_kvm.

[Jianyong Wu (Arm Technology China)]

Hi Paolo, Marc

> -----Original Message-----
> From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Sent: Thursday, September 19, 2019 7:07 PM
> To: Jianyong Wu (Arm Technology China) <Jianyong.Wu@xxxxxxx>;
> netdev@xxxxxxxxxxxxxxx; yangbo.lu@xxxxxxx; john.stultz@xxxxxxxxxx;
> tglx@xxxxxxxxxxxxx; sean.j.christopherson@xxxxxxxxx; maz@xxxxxxxxxx;
> richardcochran@xxxxxxxxx; Mark Rutland <Mark.Rutland@xxxxxxx>; Will
> Deacon <Will.Deacon@xxxxxxx>; Suzuki Poulose
> <Suzuki.Poulose@xxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; Steve Capper
> <Steve.Capper@xxxxxxx>; Kaly Xin (Arm Technology China)
> <Kaly.Xin@xxxxxxx>; Justin He (Arm Technology China)
> <Justin.He@xxxxxxx>; nd <nd@xxxxxxx>; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [RFC PATCH v3 4/6] psci: Add hvc call service for ptp_kvm.
> 
> On 19/09/19 11:46, Jianyong Wu (Arm Technology China) wrote:
> >> On 18/09/19 11:57, Jianyong Wu (Arm Technology China) wrote:
> >>> Paolo Bonzini wrote:
> >>>> This is not Y2038-safe.  Please use ktime_get_real_ts64 instead,
> >>>> and split the 64-bit seconds value between val[0] and val[1].
> >
> > Val[] should be long not u32 I think, so in arm64 I can avoid that
> > Y2038_safe, but also need rewrite for arm32.
> 
> I don't think there's anything inherently wrong with u32 val[], and as you
> notice it lets you reuse code between arm and arm64.  It's up to you and
> Marc to decide.
> 
To compatible 32-bit, Integrates second value and nanosecond value as a nanosecond value then split it into val[0] and val[1] and split cycle value into val[2] and val[3],
 In this way, time will overflow at Y2262.
WDYT?

Thanks
Jianyong Wu