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

[Tony Krowiak]

On 07/09/2018 04:38 PM, Pierre Morel wrote:
> 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?

I find it to have great value when configuring the mdev. It provides a 
view of
what has been configured thus far.

>