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

Cornelia Huck
2018-09-20T15:50:41Z

On Wed, 12 Sep 2018 15:42:55 -0400
Tony Krowiak <akrowiak@linux.vnet.ibm.com> wrote:

> From: Tony Krowiak <akrowiak@linux.ibm.com>
>
> 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@linux.ibm.com>
> Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
> Tested-by: Michael Mueller <mimu@linux.ibm.com>
> Tested-by: Farhan Ali <alifm@linux.ibm.com>
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
> 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 */

?

> + 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@linux.ibm.com>
> + * Halil Pasic <pasic@linux.ibm.com>
> *
> * 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)?

> + * 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@redhat.com>