Re: [PATCH v10 05/26] s390: vfio-ap: register matrix device with VFIO mdev framework

From: Tony Krowiak
Date: Thu Sep 20 2018 - 16:35:19 EST


On 09/20/2018 11:50 AM, Cornelia Huck wrote:
On Wed, 12 Sep 2018 15:42:55 -0400
Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx> wrote:

From: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>

Registers the matrix device created by the VFIO AP device
driver with the VFIO mediated device framework.
Registering the matrix device will create the sysfs
structures needed to create mediated matrix devices
each of which will be used to configure the AP matrix
for a guest and connect it to the VFIO AP device driver.

Registering the matrix device with the VFIO mediated device
framework will create the following sysfs structures:

/sys/devices/vfio_ap/matrix/
...... [mdev_supported_types]
......... [vfio_ap-passthrough]
............ create

To create a mediated device for the AP matrix device, write a UUID
to the create file:

uuidgen > create

A symbolic link to the mediated device's directory will be created in the
devices subdirectory named after the generated $uuid:

/sys/devices/vfio_ap/matrix/
...... [mdev_supported_types]
......... [vfio_ap-passthrough]
............ [devices]
............... [$uuid]

A symbolic link to the mediated device will also be created
in the vfio_ap matrix's directory:

/sys/devices/vfio_ap/matrix/[$uuid]

Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
Reviewed-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
Tested-by: Michael Mueller <mimu@xxxxxxxxxxxxx>
Tested-by: Farhan Ali <alifm@xxxxxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
MAINTAINERS | 1 +
drivers/s390/crypto/Makefile | 2 +-
drivers/s390/crypto/vfio_ap_drv.c | 19 +++++
drivers/s390/crypto/vfio_ap_ops.c | 126 +++++++++++++++++++++++++++++++++
drivers/s390/crypto/vfio_ap_private.h | 49 +++++++++++++
include/uapi/linux/vfio.h | 1 +
6 files changed, 197 insertions(+), 1 deletions(-)
create mode 100644 drivers/s390/crypto/vfio_ap_ops.c
(...)

diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
index 3e635f0..75f8bdc 100644
--- a/drivers/s390/crypto/vfio_ap_drv.c
+++ b/drivers/s390/crypto/vfio_ap_drv.c
@@ -76,6 +76,16 @@ static int vfio_ap_matrix_dev_create(void)
goto matrix_alloc_err;
}
+ /* Test if PQAP(QCI) instruction is available */
/* Fill in config info via PQAP(QCI), if available */

Okay


?

+ if (test_facility(12)) {
+ ret = ap_qci(&matrix_dev->info);
+ if (ret)
+ goto matrix_alloc_err;
+ }
+
+ mutex_init(&matrix_dev->lock);
+ INIT_LIST_HEAD(&matrix_dev->mdev_list);
+
matrix_dev->device.type = &vfio_ap_dev_type;
dev_set_name(&matrix_dev->device, "%s", VFIO_AP_DEV_NAME);
matrix_dev->device.parent = root_device;
(...)

diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index 6141420..a2eab78 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -3,6 +3,7 @@
* Private data and functions for adjunct processor VFIO matrix driver.
*
* Author(s): Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
+ * Halil Pasic <pasic@xxxxxxxxxxxxx>
*
* Copyright IBM Corp. 2018
*/
@@ -24,11 +25,59 @@
/**
* ap_matrix_dev - the AP matrix device structure
* @device: generic device structure associated with the AP matrix device
+ * @available_instances: number of mediated matrix devices that can be created
+ * @info: the struct containing the output from the PQAP(TAPQ) instruction
Hm, isn't that rather PQAP(QCI)?

Yes it is!


+ * mdev_list: the list of mediated matrix devices created
+ * lock: mutex for locking the AP matrix device. This lock will be
+ * taken every time we fiddle with state managed by the vfio_ap
+ * driver, be it using @mdev_list or writing the state of a
+ * single ap_matrix_mdev device. It's quite coarse but we don't
+ * expect much contention.
*/
struct ap_matrix_dev {
struct device device;
+ atomic_t available_instances;
+ struct ap_config_info info;
+ struct list_head mdev_list;
+ struct mutex lock;
};
Otherwise:
Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>