Re: [kvm-unit-tests PATCH v5 2/4] lib/s390x: add CPU timer related defines and functions

[Janosch Frank <frankja@linux.ibm.com>]

On 8/23/22 10:45, Nico Boehr wrote:
> Upcoming changes will make use of the CPU timer, so add some defines and
> functions to work with the CPU timer.
> 
> Since shifts for both CPU timer and TOD clock are the same, introduce a
> new define S390_CLOCK_SHIFT_US. The respective shifts for CPU timer and

introduce the new constant "S390_CLOCK_SHIFT_US" for that value

> TOD clock reference it, so the semantic difference between the two
> defines is kept.
> 
> Also add a define for the CPU timer subclass mask.

Constant

> 
> Signed-off-by: Nico Boehr <nrb@linux.ibm.com>

Reviewed-by: Janosch Frank <frankja@linux.ibm.com>

> ---
>   lib/s390x/asm/arch_def.h |  1 +
>   lib/s390x/asm/time.h     | 17 ++++++++++++++++-
>   2 files changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
> index e7ae454b3a33..b92291e8ae3f 100644
> --- a/lib/s390x/asm/arch_def.h
> +++ b/lib/s390x/asm/arch_def.h
> @@ -78,6 +78,7 @@ struct cpu {
>   #define CTL0_EMERGENCY_SIGNAL			(63 - 49)
>   #define CTL0_EXTERNAL_CALL			(63 - 50)
>   #define CTL0_CLOCK_COMPARATOR			(63 - 52)
> +#define CTL0_CPU_TIMER				(63 - 53)
>   #define CTL0_SERVICE_SIGNAL			(63 - 54)
>   #define CR0_EXTM_MASK			0x0000000000006200UL /* Combined external masks */
>   
> diff --git a/lib/s390x/asm/time.h b/lib/s390x/asm/time.h
> index 7652a151e87a..d8d91d68a667 100644
> --- a/lib/s390x/asm/time.h
> +++ b/lib/s390x/asm/time.h
> @@ -11,9 +11,13 @@
>   #ifndef _ASMS390X_TIME_H_
>   #define _ASMS390X_TIME_H_
>   
> -#define STCK_SHIFT_US	(63 - 51)
> +#define S390_CLOCK_SHIFT_US	(63 - 51)
> +
> +#define STCK_SHIFT_US	S390_CLOCK_SHIFT_US
>   #define STCK_MAX	((1UL << 52) - 1)
>   
> +#define CPU_TIMER_SHIFT_US	S390_CLOCK_SHIFT_US
> +
>   static inline uint64_t get_clock_us(void)
>   {
>   	uint64_t clk;
> @@ -45,4 +49,15 @@ static inline void mdelay(unsigned long ms)
>   	udelay(ms * 1000);
>   }
>   
> +static inline void cpu_timer_set_ms(int64_t timeout_ms)
> +{
> +	int64_t timer_value = (timeout_ms * 1000) << CPU_TIMER_SHIFT_US;
> +
> +	asm volatile (
> +		"spt %[timer_value]\n"
> +		:
> +		: [timer_value] "Q" (timer_value)
> +	);
> +}
> +
>   #endif