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

[Tony Krowiak]

On 07/12/2018 01:22 AM, Halil Pasic wrote:
> 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.

Since test system has only 15 domains defined this has never been a
problem. I'll write a function rather than using the bitmap_or().

> > +}