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

Halil Pasic
2018-07-11T23:22:57Z

On 06/29/2018 11:11 PM, Tony Krowiak wrote:
> From: Tony Krowiak <akrowiak@linux.ibm.com>
>
> 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.

> +}