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s390/vfio-ap: add status attribute to AP queue device's sysfs dir

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This patch adds a sysfs 'status' attribute to a queue device when it is
bound to the vfio_ap device driver. The field displays a string indicating
the status of the queue device:

Status String:  Indicates:
-------------   ---------
"assigned"      the queue is assigned to an mdev, but is not in use by a
                KVM guest.
"in use"        the queue is assigned to an mdev and is in use by a KVM
                guest.
"unassigned"    the queue is not assigned to an mdev.

The status string will be displayed by the 'lszcrypt' command if the queue
device is bound to the vfio_ap device driver.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
[akrowiak@linux.ibm.com: added check for queue in use by guest]
Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
Tony Krowiak 2021-10-27 11:20:14 -04:00 committed by Heiko Carstens
parent 402ff5a338
commit f139862b92
1 changed files with 76 additions and 3 deletions
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79
drivers/s390/crypto/vfio_ap_drv.c
View file

@ -17,6 +17,9 @@
#define VFIO_AP_ROOT_NAME "vfio_ap"
#define VFIO_AP_DEV_NAME "matrix"
#define AP_QUEUE_ASSIGNED "assigned"
#define AP_QUEUE_UNASSIGNED "unassigned"
#define AP_QUEUE_IN_USE "in use"
MODULE_AUTHOR("IBM Corporation");
MODULE_DESCRIPTION("VFIO AP device driver, Copyright IBM Corp. 2018");
@ -41,26 +44,95 @@ static struct ap_device_id ap_queue_ids[] = {
MODULE_DEVICE_TABLE(vfio_ap, ap_queue_ids);
static struct ap_matrix_mdev *vfio_ap_mdev_for_queue(struct vfio_ap_queue *q)
{
struct ap_matrix_mdev *matrix_mdev;
unsigned long apid = AP_QID_CARD(q->apqn);
unsigned long apqi = AP_QID_QUEUE(q->apqn);
list_for_each_entry(matrix_mdev, &matrix_dev->mdev_list, node) {
if (test_bit_inv(apid, matrix_mdev->matrix.apm) &&
test_bit_inv(apqi, matrix_mdev->matrix.aqm))
return matrix_mdev;
}
return NULL;
}
static ssize_t status_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
ssize_t nchars = 0;
struct vfio_ap_queue *q;
struct ap_matrix_mdev *matrix_mdev;
struct ap_device *apdev = to_ap_dev(dev);
mutex_lock(&matrix_dev->lock);
q = dev_get_drvdata(&apdev->device);
matrix_mdev = vfio_ap_mdev_for_queue(q);
if (matrix_mdev) {
if (matrix_mdev->kvm)
nchars = scnprintf(buf, PAGE_SIZE, "%s\n",
AP_QUEUE_IN_USE);
else
nchars = scnprintf(buf, PAGE_SIZE, "%s\n",
AP_QUEUE_ASSIGNED);
} else {
nchars = scnprintf(buf, PAGE_SIZE, "%s\n",
AP_QUEUE_UNASSIGNED);
}
mutex_unlock(&matrix_dev->lock);
return nchars;
}
static DEVICE_ATTR_RO(status);
static struct attribute *vfio_queue_attrs[] = {
&dev_attr_status.attr,
NULL,
};
static const struct attribute_group vfio_queue_attr_group = {
.attrs = vfio_queue_attrs,
};
/**
* vfio_ap_queue_dev_probe: Allocate a vfio_ap_queue structure and associate it
* with the device as driver_data.
*
* @apdev: the AP device being probed
*
* Return: returns 0 if the probe succeeded; otherwise, returns -ENOMEM if
* storage could not be allocated for a vfio_ap_queue object.
* Return: returns 0 if the probe succeeded; otherwise, returns an error if
* storage could not be allocated for a vfio_ap_queue object or the
* sysfs 'status' attribute could not be created for the queue device.
*/
static int vfio_ap_queue_dev_probe(struct ap_device *apdev)
{
int ret;
struct vfio_ap_queue *q;
q = kzalloc(sizeof(*q), GFP_KERNEL);
if (!q)
return -ENOMEM;
mutex_lock(&matrix_dev->lock);
dev_set_drvdata(&apdev->device, q);
q->apqn = to_ap_queue(&apdev->device)->qid;
q->saved_isc = VFIO_AP_ISC_INVALID;
return 0;
ret = sysfs_create_group(&apdev->device.kobj, &vfio_queue_attr_group);
if (ret) {
dev_set_drvdata(&apdev->device, NULL);
kfree(q);
}
mutex_unlock(&matrix_dev->lock);
return ret;
}
/**
@ -75,6 +147,7 @@ static void vfio_ap_queue_dev_remove(struct ap_device *apdev)
struct vfio_ap_queue *q;
mutex_lock(&matrix_dev->lock);
sysfs_remove_group(&apdev->device.kobj, &vfio_queue_attr_group);
q = dev_get_drvdata(&apdev->device);
vfio_ap_mdev_reset_queue(q, 1);
dev_set_drvdata(&apdev->device, NULL);