Re: [PATCH 4/4] s390/vfio-ap: Use AP_DOMAINS for adm_add bitmap size in vfio_ap_mdev_cfg_add()

["Jason J. Herne" <jjherne@linux.ibm.com>]

On 8/24/26 9:58 AM, Anthony Krowiak wrote:
> In vfio_ap_mdev_cfg_add(), the bitmap_and() call that computes
> the intersection of newly added control domains with those
> assigned to each matrix mdev passes AP_DEVICES as the bitmap
> size instead of AP_DOMAINS:
> 
>      bitmap_and(matrix_mdev->adm_add,
>                 matrix_mdev->matrix.adm, adm_add, AP_DEVICES);
> 
> Control domains are indexed by AP queue index (APQI) and their
> bitmaps are sized by AP_DOMAINS, not AP_DEVICES. The two
> constants are both 256 today so there is no functional impact,
> but the wrong constant is inconsistent with the two bitmap_and()
> calls immediately above it and with every other operation on
> adm/aqm bitmaps in the file, all of which correctly use
> AP_DOMAINS.
> 
> Use AP_DOMAINS to keep the code consistent and correct in case
> the two constants ever diverge.
> 
> Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
> ---
>   drivers/s390/crypto/vfio_ap_ops.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index c7eebbd0ed40..e62e0dfa7282 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -2840,7 +2840,7 @@ static void vfio_ap_mdev_cfg_add(unsigned long *apm_add, unsigned long *aqm_add,
>   		bitmap_and(matrix_mdev->aqm_add,
>   			   matrix_mdev->matrix.aqm, aqm_add, AP_DOMAINS);
>   		bitmap_and(matrix_mdev->adm_add,
> -			   matrix_mdev->matrix.adm, adm_add, AP_DEVICES);
> +			   matrix_mdev->matrix.adm, adm_add, AP_DOMAINS);
>   
>   		mutex_unlock(&matrix_dev->mdevs_lock);
>   	}

Reviewed-by: Jason J. Herne <jjherne@linux.ibm.com>