Re: [kvm-unit-tests PATCH 2/4] lib: s390x: sclp: Extend feature probing

[David Hildenbrand <david@redhat.com>]

On 10.05.21 17:00, Janosch Frank wrote:
> Lets grab more of the feature bits from SCLP read info so we can use
> them in the cpumodel tests.
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> ---
>   lib/s390x/sclp.c | 20 ++++++++++++++++++++
>   lib/s390x/sclp.h | 38 +++++++++++++++++++++++++++++++++++---
>   2 files changed, 55 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
> index f11c2035..f25cfdb2 100644
> --- a/lib/s390x/sclp.c
> +++ b/lib/s390x/sclp.c
> @@ -129,6 +129,13 @@ CPUEntry *sclp_get_cpu_entries(void)
>   	return (CPUEntry *)(_read_info + read_info->offset_cpu);
>   }
>   
> +static bool sclp_feat_check(int byte, int mask)
> +{
> +	uint8_t *rib = (uint8_t *)read_info;
> +
> +	return !!(rib[byte] & mask);
> +}

Instead of a mask, I'd just check for bit (offset) numbers within the byte.

static bool sclp_feat_check(int byte, int bit)
{
	uint8_t *rib = (uint8_t *)read_info;

	return !!(rib[byte] & (0x80 >> bit));
}

-- 
Thanks,

David / dhildenb