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Subject[PATCH v7 04/15] s390/vfio-ap: implement in-use callback for vfio_ap driver
Date
Let's implement the callback to indicate when an APQN
is in use by the vfio_ap device driver. The callback is
invoked whenever a change to the apmask or aqmask would
result in one or more queue devices being removed from the driver. The
vfio_ap device driver will indicate a resource is in use
if the APQN of any of the queue devices to be removed are assigned to
any of the matrix mdevs under the driver's control.

Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_drv.c | 1 +
drivers/s390/crypto/vfio_ap_ops.c | 47 +++++++++++++++++----------
drivers/s390/crypto/vfio_ap_private.h | 2 ++
3 files changed, 33 insertions(+), 17 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
index e9c226c0730e..5197a1fe14d4 100644
--- a/drivers/s390/crypto/vfio_ap_drv.c
+++ b/drivers/s390/crypto/vfio_ap_drv.c
@@ -174,6 +174,7 @@ static int __init vfio_ap_init(void)
memset(&vfio_ap_drv, 0, sizeof(vfio_ap_drv));
vfio_ap_drv.probe = vfio_ap_queue_dev_probe;
vfio_ap_drv.remove = vfio_ap_queue_dev_remove;
+ vfio_ap_drv.in_use = vfio_ap_mdev_resource_in_use;
vfio_ap_drv.ids = ap_queue_ids;

ret = ap_driver_register(&vfio_ap_drv, THIS_MODULE, VFIO_AP_DRV_NAME);
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 00699bd72d2b..8ece0d52ff4c 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -500,7 +500,9 @@ vfio_ap_mdev_verify_queues_reserved_for_apid(struct ap_matrix_mdev *matrix_mdev,
*
* Returns 0 if the APQNs are not shared, otherwise; returns -EADDRINUSE.
*/
-static int vfio_ap_mdev_verify_no_sharing(struct ap_matrix_mdev *matrix_mdev)
+static int vfio_ap_mdev_verify_no_sharing(struct ap_matrix_mdev *matrix_mdev,
+ unsigned long *mdev_apm,
+ unsigned long *mdev_aqm)
{
struct ap_matrix_mdev *lstdev;
DECLARE_BITMAP(apm, AP_DEVICES);
@@ -517,12 +519,10 @@ static int vfio_ap_mdev_verify_no_sharing(struct ap_matrix_mdev *matrix_mdev)
* We work on full longs, as we can only exclude the leftover
* bits in non-inverse order. The leftover is all zeros.
*/
- if (!bitmap_and(apm, matrix_mdev->matrix.apm,
- lstdev->matrix.apm, AP_DEVICES))
+ if (!bitmap_and(apm, mdev_apm, lstdev->matrix.apm, AP_DEVICES))
continue;

- if (!bitmap_and(aqm, matrix_mdev->matrix.aqm,
- lstdev->matrix.aqm, AP_DOMAINS))
+ if (!bitmap_and(aqm, mdev_aqm, lstdev->matrix.aqm, AP_DOMAINS))
continue;

return -EADDRINUSE;
@@ -594,6 +594,7 @@ static ssize_t assign_adapter_store(struct device *dev,
{
int ret;
unsigned long apid;
+ DECLARE_BITMAP(apm, AP_DEVICES);
struct mdev_device *mdev = mdev_from_dev(dev);
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);

@@ -619,18 +620,18 @@ static ssize_t assign_adapter_store(struct device *dev,
if (ret)
goto done;

- set_bit_inv(apid, matrix_mdev->matrix.apm);
+ memset(apm, 0, sizeof(apm));
+ set_bit_inv(apid, apm);

- ret = vfio_ap_mdev_verify_no_sharing(matrix_mdev);
+ ret = vfio_ap_mdev_verify_no_sharing(matrix_mdev, apm,
+ matrix_mdev->matrix.aqm);
if (ret)
- goto share_err;
+ goto done;

+ set_bit_inv(apid, matrix_mdev->matrix.apm);
vfio_ap_mdev_qlinks_for_apid(matrix_mdev, apid);
ret = count;
- goto done;

-share_err:
- clear_bit_inv(apid, matrix_mdev->matrix.apm);
done:
mutex_unlock(&matrix_dev->lock);

@@ -767,6 +768,7 @@ static ssize_t assign_domain_store(struct device *dev,
{
int ret;
unsigned long apqi;
+ DECLARE_BITMAP(aqm, AP_DOMAINS);
struct mdev_device *mdev = mdev_from_dev(dev);
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
unsigned long max_apqi = matrix_mdev->matrix.aqm_max;
@@ -787,18 +789,18 @@ static ssize_t assign_domain_store(struct device *dev,
if (ret)
goto done;

- set_bit_inv(apqi, matrix_mdev->matrix.aqm);
+ memset(aqm, 0, sizeof(aqm));
+ set_bit_inv(apqi, aqm);

- ret = vfio_ap_mdev_verify_no_sharing(matrix_mdev);
+ ret = vfio_ap_mdev_verify_no_sharing(matrix_mdev,
+ matrix_mdev->matrix.apm, aqm);
if (ret)
- goto share_err;
+ goto done;

+ set_bit_inv(apqi, matrix_mdev->matrix.aqm);
vfio_ap_mdev_qlinks_for_apqi(matrix_mdev, apqi);
ret = count;
- goto done;

-share_err:
- clear_bit_inv(apqi, matrix_mdev->matrix.aqm);
done:
mutex_unlock(&matrix_dev->lock);

@@ -1369,3 +1371,14 @@ void vfio_ap_mdev_remove_queue(struct ap_queue *queue)
kfree(q);
mutex_unlock(&matrix_dev->lock);
}
+
+bool vfio_ap_mdev_resource_in_use(unsigned long *apm, unsigned long *aqm)
+{
+ bool in_use;
+
+ mutex_lock(&matrix_dev->lock);
+ in_use = vfio_ap_mdev_verify_no_sharing(NULL, apm, aqm) ? true : false;
+ mutex_unlock(&matrix_dev->lock);
+
+ return in_use;
+}
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index e1f8c82cc55d..4b6e144bab17 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -105,4 +105,6 @@ struct vfio_ap_queue {
int vfio_ap_mdev_probe_queue(struct ap_queue *queue);
void vfio_ap_mdev_remove_queue(struct ap_queue *queue);

+bool vfio_ap_mdev_resource_in_use(unsigned long *apm, unsigned long *aqm);
+
#endif /* _VFIO_AP_PRIVATE_H_ */
--
2.21.1
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