Re: [PATCH v6 15/21] s390: vfio-ap: configure the guest's AP matrix

[Halil Pasic]

On 06/29/2018 11:11 PM, Tony Krowiak wrote:
> From: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
>
> Configures the AP adapters, usage domains and control domains for the
> KVM guest from the matrix configured via the mediated matrix device's
> sysfs attribute files.
[..]
> +
> +static void kvm_ap_set_crycb_masks(struct ap_matrix_mdev *matrix_mdev)
> +{
> +	int nbytes;
> +	unsigned long *apm, *aqm, *adm;
> +
> +	kvm_ap_clear_crycb_masks(matrix_mdev);
> +
> +	apm = kvm_ap_get_crycb_apm(matrix_mdev);
> +	aqm = kvm_ap_get_crycb_aqm(matrix_mdev);
> +	adm = kvm_ap_get_crycb_adm(matrix_mdev);
> +
> +	nbytes = KVM_AP_MASK_BYTES(matrix_mdev->matrix.apm_max + 1);
> +	memcpy(apm, matrix_mdev->matrix.apm, nbytes);
> +
> +	nbytes = KVM_AP_MASK_BYTES(matrix_mdev->matrix.aqm_max + 1);
> +	memcpy(aqm, matrix_mdev->matrix.aqm, nbytes);
> +
> +	/*
> +	 * Merge the AQM and ADM since the ADM is a superset of the
> +	 * AQM by agreed-upon convention.
> +	 */
> +	bitmap_or(adm, matrix_mdev->matrix.adm, matrix_mdev->matrix.aqm,
> +		  matrix_mdev->matrix.adm_max + 1);

Are you sure this or works as expected? E.g. if adm_max == 15 the bitmaps
include the least significant 2 bytes but you want the other two.

> +}