Re: [PATCH v9 09/22] s390: vfio-ap: register matrix device with VFIO mdev framework

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

On 13/08/2018 23:48, Tony Krowiak 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/[$uuid]
> 
> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
> Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
> Tested-by: Michael Mueller <mimu@linux.ibm.com>
> Tested-by: Farhan Ali <alifm@linux.ibm.com>
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
>   MAINTAINERS                           |    1 +
>   drivers/s390/crypto/Makefile          |    2 +-
>   drivers/s390/crypto/vfio_ap_drv.c     |   23 ++++++
>   drivers/s390/crypto/vfio_ap_ops.c     |  124 +++++++++++++++++++++++++++++++++
>   drivers/s390/crypto/vfio_ap_private.h |   45 ++++++++++++
>   include/uapi/linux/vfio.h             |    1 +
>   6 files changed, 195 insertions(+), 1 deletions(-)
>   create mode 100644 drivers/s390/crypto/vfio_ap_ops.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index e84c559..f60dd56 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -12427,6 +12427,7 @@ W:	http://www.ibm.com/developerworks/linux/linux390/
>   S:	Supported
>   F:	drivers/s390/crypto/vfio_ap_drv.c
>   F:	drivers/s390/crypto/vfio_ap_private.h
> +F:	drivers/s390/crypto/vfio_ap_ops.c
> 
>   S390 ZFCP DRIVER
>   M:	Steffen Maier <maier@linux.ibm.com>
> diff --git a/drivers/s390/crypto/Makefile b/drivers/s390/crypto/Makefile
> index 48e466e..8d36b05 100644
> --- a/drivers/s390/crypto/Makefile
> +++ b/drivers/s390/crypto/Makefile
> @@ -17,5 +17,5 @@ pkey-objs := pkey_api.o
>   obj-$(CONFIG_PKEY) += pkey.o
> 
>   # adjunct processor matrix
> -vfio_ap-objs := vfio_ap_drv.o
> +vfio_ap-objs := vfio_ap_drv.o vfio_ap_ops.o
>   obj-$(CONFIG_VFIO_AP) += vfio_ap.o
> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
> index 5069580..fa04c5a 100644
> --- a/drivers/s390/crypto/vfio_ap_drv.c
> +++ b/drivers/s390/crypto/vfio_ap_drv.c
> @@ -11,6 +11,7 @@
>   #include <linux/mod_devicetable.h>
>   #include <linux/slab.h>
>   #include <linux/string.h>
> +#include <asm/zcrypt.h>
>   #include "vfio_ap_private.h"
> 
>   #define VFIO_AP_ROOT_NAME "vfio_ap"
> @@ -65,6 +66,19 @@ static int vfio_ap_matrix_dev_init(void)
>   		return ret;
>   	}
> 
> +	mutex_init(&matrix_dev.lock);
> +	INIT_LIST_HEAD(&matrix_dev.mdev_list);
> +
> +	/* Test if PQAP(QCI) instruction is available */
> +	if (test_facility(12)) {
> +		ret = ap_qci(&matrix_dev.info);
> +		if (ret) {
> +			root_device_unregister(root_device);
> +			return ret;
> +		}
> +	}
> +
> +	atomic_set(&matrix_dev.available_instances, MAX_ZDEV_ENTRIES_EXT);
>   	matrix_dev.device.type = &vfio_ap_dev_type;
>   	dev_set_name(&matrix_dev.device, "%s", VFIO_AP_DEV_NAME);
>   	matrix_dev.device.type = &vfio_ap_dev_type;
> @@ -105,11 +119,20 @@ int __init vfio_ap_init(void)
>   		return ret;
>   	}
> 
> +	ret = vfio_ap_mdev_register();
> +	if (ret) {
> +		ap_driver_unregister(&vfio_ap_drv);
> +		vfio_ap_matrix_dev_destroy();
> +
> +		return ret;
> +	}
> +
>   	return 0;
>   }
> 
>   void __exit vfio_ap_exit(void)
>   {
> +	vfio_ap_mdev_unregister();
>   	ap_driver_unregister(&vfio_ap_drv);
>   	vfio_ap_matrix_dev_destroy();
>   }
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> new file mode 100644
> index 0000000..8018c2d
> --- /dev/null
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -0,0 +1,124 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Adjunct processor matrix VFIO device driver callbacks.
> + *
> + * Copyright IBM Corp. 2018
> + *
> + * Author(s): Tony Krowiak <akrowiak@linux.ibm.com>
> + *	      Halil Pasic <pasic@linux.ibm.com>
> + *	      Pierre Morel <pmorel@linux.ibm.com>
> + */
> +#include <linux/string.h>
> +#include <linux/vfio.h>
> +#include <linux/device.h>
> +#include <linux/list.h>
> +#include <linux/ctype.h>
> +
> +#include "vfio_ap_private.h"
> +
> +#define VFIO_AP_MDEV_TYPE_HWVIRT "passthrough"
> +#define VFIO_AP_MDEV_NAME_HWVIRT "VFIO AP Passthrough Device"
> +
> +static void vfio_ap_matrix_init(struct ap_config_info *info,
> +				struct ap_matrix *matrix)
> +{
> +	matrix->apm_max = info->apxa ? info->Na : 63;
> +	matrix->aqm_max = info->apxa ? info->Nd : 15;
> +	matrix->adm_max = info->apxa ? info->Nd : 15;
> +}
> +
> +static int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
> +{
> +	struct ap_matrix_mdev *matrix_mdev;
> +
> +	matrix_mdev = kzalloc(sizeof(*matrix_mdev), GFP_KERNEL);
> +	if (!matrix_mdev)
> +		return -ENOMEM;
> +
> +	matrix_mdev->name = dev_name(mdev_dev(mdev));
> +	vfio_ap_matrix_init(&matrix_dev.info, &matrix_mdev->matrix);
> +	mdev_set_drvdata(mdev, matrix_mdev);
> +
> +	if (atomic_dec_if_positive(&matrix_dev.available_instances) < 0) {
> +		kfree(matrix_mdev);
> +		return -EPERM;
> +	}
> +
> +	mutex_lock(&matrix_dev.lock);
> +	list_add(&matrix_mdev->list, &matrix_dev.mdev_list);
> +	mutex_unlock(&matrix_dev.lock);
> +
Hi Tony,

You need to initialize the matrix_mdev->list before
using it.

Regards,
Pierre


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