Re: [PATCH v3 11/14] s390: vfio-ap: sysfs interface to view matrix mdev matrix

[Pierre Morel <pmorel@linux.vnet.ibm.com>]

On 14/03/2018 19:25, 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@linux.vnet.ibm.com>
> ---
>   drivers/s390/crypto/vfio_ap_ops.c |   39 +++++++++++++++++++++++++++++++++++++
>   1 files changed, 39 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index 461d450..04f7a92 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -692,6 +692,44 @@ 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;
> +	int nchars = 0;
> +	int n;
> +
> +	n = sprintf(bufpos, "ADAPTER.DOMAIN\n");

For easy parsing it is better to only report the interesting data
and let a user space utility make fancy presentation.

> +	bufpos += n;
> +	nchars += n;
> +
> +	n = sprintf(bufpos, "--------------\n");
> +	bufpos += n;
> +	nchars += n;
> +
> +	for_each_set_bit_inv(apid, matrix_mdev->matrix->apm,
> +			     matrix_mdev->matrix->apm_max) {
> +		n = sprintf(bufpos, "%02lx\n", apid);
> +		bufpos += n;
> +		nchars += n;
> +
> +		for_each_set_bit_inv(apqi, matrix_mdev->matrix->aqm,
> +				     matrix_mdev->matrix->aqm_max) {
> +			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,
> @@ -700,6 +738,7 @@ 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,
>   };
>

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