RE: [PATCH v5 4/6] psci: Add hvc call service for ptp_kvm.

[Jianyong Wu (Arm Technology China)]

Hi Paolo,

> -----Original Message-----
> From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Sent: Wednesday, October 16, 2019 3:25 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@xxxxxxxxxx; Suzuki Poulose <Suzuki.Poulose@xxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> kvmarm@xxxxxxxxxxxxxxxxxxxxx; 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>
> Subject: Re: [PATCH v5 4/6] psci: Add hvc call service for ptp_kvm.
> 
> On 15/10/19 12:48, Jianyong Wu wrote:
> > diff --git a/drivers/clocksource/arm_arch_timer.c
> > b/drivers/clocksource/arm_arch_timer.c
> > index 07e57a49d1e8..3597f1f27b10 100644
> > --- a/drivers/clocksource/arm_arch_timer.c
> > +++ b/drivers/clocksource/arm_arch_timer.c
> > @@ -1634,3 +1634,8 @@ static int __init arch_timer_acpi_init(struct
> > acpi_table_header *table)  }  TIMER_ACPI_DECLARE(arch_timer,
> > ACPI_SIG_GTDT, arch_timer_acpi_init);  #endif
> > +
> > +bool is_arm_arch_counter(void *cs)
> > +{
> > +	return (struct clocksource *)cs == &clocksource_counter; }
> 
> As Thomas pointed out, any reason to have a void * here?

Need fix.

Thanks
Jianyong 

> 
> However, since he didn't like modifying the struct, here is an alternative idea:
> 
> 1) add a "struct clocksource*" argument to ktime_get_snapshot
> 
> 2) return -ENODEV if the argument is not NULL and is not the current
> clocksource
> 
> 3) move the implementation of the hypercall to
> drivers/clocksource/arm_arch_timer.c, so that it can call
> ktime_get_snapshot(&systime_snapshot, &clocksource_counter);
> 
> Paolo