Re: [PATCH v6 13/21] s390: vfio-ap: sysfs interface to view matrix mdev matrix

[Pierre Morel <pmorel@xxxxxxxxxxxxx>]

On 09/07/2018 14:20, Pierre Morel wrote:
> On 29/06/2018 23:11, Tony Krowiak wrote:
> > Provides a sysfs interface to view the AP matrix configured for the
> > mediated matrix device.
> >
> > The relevant sysfs structures are:
> >
> > /sys/devices/vfio_ap
> > ... [matrix]
> > ...... [mdev_supported_types]
> > ......... [vfio_ap-passthrough]
> > ............ [devices]
> > ...............[$uuid]
> > .................. matrix
> >
> > To view the matrix configured for the mediated matrix device,
> > print the matrix file:
> >
> >     cat matrix
> >
> > Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
> > ---
> >   drivers/s390/crypto/vfio_ap_ops.c |   31 
> > +++++++++++++++++++++++++++++++
> >   1 files changed, 31 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/s390/crypto/vfio_ap_ops.c 
> > b/drivers/s390/crypto/vfio_ap_ops.c
> > index c8f31f3..bc7398d 100644
> > --- a/drivers/s390/crypto/vfio_ap_ops.c
> > +++ b/drivers/s390/crypto/vfio_ap_ops.c
> > @@ -697,6 +697,36 @@ static ssize_t control_domains_show(struct 
> > device *dev,
> >   }
> >   DEVICE_ATTR_RO(control_domains);
> >
> > +static ssize_t matrix_show(struct device *dev, struct 
> > device_attribute *attr,
> > +               char *buf)
> > +{
> > +    struct mdev_device *mdev = mdev_from_dev(dev);
> > +    struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> > +    char *bufpos = buf;
> > +    unsigned long apid;
> > +    unsigned long apqi;
> > +    unsigned long napm = matrix_mdev->matrix.apm_max + 1;
> > +    unsigned long naqm = matrix_mdev->matrix.aqm_max + 1;
> > +    int nchars = 0;
> > +    int n;
> > +
> > +    for_each_set_bit_inv(apid, matrix_mdev->matrix.apm, napm) {
> > +        n = sprintf(bufpos, "%02lx\n", apid);
> > +        bufpos += n;
> > +        nchars += n;
> > +
> > +        for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm, naqm) {
> > +            n = sprintf(bufpos, "%02lx.%04lx\n", apid, apqi);
> > +            bufpos += n;
> > +            nchars += n;
> > +        }
> > +    }
> > +
> > +    return nchars;
> > +}
> > +DEVICE_ATTR_RO(matrix);
> > +
> > +
> >   static struct attribute *vfio_ap_mdev_attrs[] = {
> >       &dev_attr_assign_adapter.attr,
> >       &dev_attr_unassign_adapter.attr,
> > @@ -705,6 +735,7 @@ static ssize_t control_domains_show(struct device 
> > *dev,
> >       &dev_attr_assign_control_domain.attr,
> >       &dev_attr_unassign_control_domain.attr,
> >       &dev_attr_control_domains.attr,
> > +    &dev_attr_matrix.attr,
> >       NULL,
> >   };
>
> I have still the same remark: what you show here is not what is currently
> used by the SIE.
> It is not irrelevant but what the guest really use may be more 
> interesting
> for the admin.
OK, you implement the right view it in patch 16/21.

Still, what is the purpose of showing this view?


--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany