On Fri, 2 Oct 2020 21:39:31 +0200
Stefan Haberland <sth@xxxxxxxxxxxxx> wrote:
> From: Sebastian Ott <sebott@xxxxxxxxxxxxx>
>
> Add a new sysfs attribute 'esc' per chpid. This new attribute exports
> the Endpoint-Security-Capability byte of channel-path description block,
> which could be 0-None, 1-Authentication, 2 and 3-Encryption.
>
> For example:
> $ cat /sys/devices/css0/chp0.34/esc
> 0
>
> Reference-ID: IO1812
> Signed-off-by: Sebastian Ott <sebott@xxxxxxxxxxxxx>
> [vneethv@xxxxxxxxxxxxx: cleaned-up & modified description]
> Signed-off-by: Vineeth Vijayan <vneethv@xxxxxxxxxxxxx>
> Reviewed-by: Jan Höppner <hoeppner@xxxxxxxxxxxxx>
> Reviewed-by: Peter Oberparleiter <oberpar@xxxxxxxxxxxxx>
> Acked-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
> Signed-off-by: Stefan Haberland <sth@xxxxxxxxxxxxx>
> ---
> drivers/s390/cio/chp.c | 15 +++++++++++++++
> drivers/s390/cio/chsc.h | 3 ++-
> 2 files changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/s390/cio/chp.c b/drivers/s390/cio/chp.c
> index dfcbe54591fb..8d0de6adcad0 100644
> --- a/drivers/s390/cio/chp.c
> +++ b/drivers/s390/cio/chp.c
> @@ -384,6 +384,20 @@ static ssize_t chp_chid_external_show(struct device *dev,
> }
> static DEVICE_ATTR(chid_external, 0444, chp_chid_external_show, NULL);
>
> +static ssize_t chp_esc_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct channel_path *chp = to_channelpath(dev);
> + ssize_t rc;
> +
> + mutex_lock(&chp->lock);
> + rc = sprintf(buf, "%x\n", chp->desc_fmt1.esc);
I'm wondering: Do we need to distinguish between '0' == 'no esc, and
the hardware says so' and '0' == 'the chsc to get that information is
not supported'? I see that for the chid the code checks for a flag in
desc_fmt1, and I indeed see that nothing is displayed for
chid/chid_external when I run under QEMU.
> + mutex_unlock(&chp->lock);
> +
> + return rc;
> +}
> +static DEVICE_ATTR(esc, 0444, chp_esc_show, NULL);
> +
> static ssize_t util_string_read(struct file *filp, struct kobject *kobj,
> struct bin_attribute *attr, char *buf,
> loff_t off, size_t count)
(...)
