[PATCH v7 01/15] s390/vfio-ap: store queue struct in hash table for quick access

Tony Krowiak
2020-04-07T19:20:38Z

Rather than looping over potentially 65535 objects, let's store the
structures for caching information about queue devices bound to the
vfio_ap device driver in a hash table keyed by APQN.

Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_drv.c | 28 +++------
drivers/s390/crypto/vfio_ap_ops.c | 90 ++++++++++++++-------------
drivers/s390/crypto/vfio_ap_private.h | 10 ++-
3 files changed, 60 insertions(+), 68 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
index be2520cc010b..e9c226c0730e 100644
--- a/drivers/s390/crypto/vfio_ap_drv.c
+++ b/drivers/s390/crypto/vfio_ap_drv.c
@@ -51,15 +51,9 @@ MODULE_DEVICE_TABLE(vfio_ap, ap_queue_ids);
*/
static int vfio_ap_queue_dev_probe(struct ap_device *apdev)
{
- struct vfio_ap_queue *q;
-
- q = kzalloc(sizeof(*q), GFP_KERNEL);
- if (!q)
- return -ENOMEM;
- dev_set_drvdata(&apdev->device, q);
- q->apqn = to_ap_queue(&apdev->device)->qid;
- q->saved_isc = VFIO_AP_ISC_INVALID;
- return 0;
+ struct ap_queue *queue = to_ap_queue(&apdev->device);
+
+ return vfio_ap_mdev_probe_queue(queue);
}

/**
@@ -70,18 +64,9 @@ static int vfio_ap_queue_dev_probe(struct ap_device *apdev)
*/
static void vfio_ap_queue_dev_remove(struct ap_device *apdev)
{
- struct vfio_ap_queue *q;
- int apid, apqi;
-
- mutex_lock(&matrix_dev->lock);
- q = dev_get_drvdata(&apdev->device);
- dev_set_drvdata(&apdev->device, NULL);
- apid = AP_QID_CARD(q->apqn);
- apqi = AP_QID_QUEUE(q->apqn);
- vfio_ap_mdev_reset_queue(apid, apqi, 1);
- vfio_ap_irq_disable(q);
- kfree(q);
- mutex_unlock(&matrix_dev->lock);
+ struct ap_queue *queue = to_ap_queue(&apdev->device);
+
+ vfio_ap_mdev_remove_queue(queue);
}

static void vfio_ap_matrix_dev_release(struct device *dev)
@@ -135,6 +120,7 @@ static int vfio_ap_matrix_dev_create(void)

mutex_init(&matrix_dev->lock);
INIT_LIST_HEAD(&matrix_dev->mdev_list);
+ hash_init(matrix_dev->qtable);

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_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 5c0f53c6dde7..134860934fe7 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -26,45 +26,16 @@

static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev);

-static int match_apqn(struct device *dev, const void *data)
-{
- struct vfio_ap_queue *q = dev_get_drvdata(dev);
-
- return (q->apqn == *(int *)(data)) ? 1 : 0;
-}
-
-/**
- * vfio_ap_get_queue: Retrieve a queue with a specific APQN from a list
- * @matrix_mdev: the associated mediated matrix
- * @apqn: The queue APQN
- *
- * Retrieve a queue with a specific APQN from the list of the
- * devices of the vfio_ap_drv.
- * Verify that the APID and the APQI are set in the matrix.
- *
- * Returns the pointer to the associated vfio_ap_queue
- */
-static struct vfio_ap_queue *vfio_ap_get_queue(
- struct ap_matrix_mdev *matrix_mdev,
- int apqn)
+struct vfio_ap_queue *vfio_ap_get_queue(unsigned long apqn)
{
struct vfio_ap_queue *q;
- struct device *dev;
-
- if (!test_bit_inv(AP_QID_CARD(apqn), matrix_mdev->matrix.apm))
- return NULL;
- if (!test_bit_inv(AP_QID_QUEUE(apqn), matrix_mdev->matrix.aqm))
- return NULL;
-
- dev = driver_find_device(&matrix_dev->vfio_ap_drv->driver, NULL,
- &apqn, match_apqn);
- if (!dev)
- return NULL;
- q = dev_get_drvdata(dev);
- q->matrix_mdev = matrix_mdev;
- put_device(dev);

- return q;
+ hash_for_each_possible(matrix_dev->qtable, q, qnode, apqn) {
+ if (q && (apqn == q->apqn))
+ return q;
+ }
+
+ return NULL;
}

/**
@@ -293,10 +264,11 @@ static int handle_pqap(struct kvm_vcpu *vcpu)
matrix_mdev = container_of(vcpu->kvm->arch.crypto.pqap_hook,
struct ap_matrix_mdev, pqap_hook);

- q = vfio_ap_get_queue(matrix_mdev, apqn);
+ q = vfio_ap_get_queue(apqn);
if (!q)
goto out_unlock;

+ q->matrix_mdev = matrix_mdev;
status = vcpu->run->s.regs.gprs[1];

/* If IR bit(16) is set we enable the interrupt */
@@ -1116,16 +1088,11 @@ static int vfio_ap_mdev_group_notifier(struct notifier_block *nb,

static void vfio_ap_irq_disable_apqn(int apqn)
{
- struct device *dev;
struct vfio_ap_queue *q;

- dev = driver_find_device(&matrix_dev->vfio_ap_drv->driver, NULL,
- &apqn, match_apqn);
- if (dev) {
- q = dev_get_drvdata(dev);
+ q = vfio_ap_get_queue(apqn);
+ if (q)
vfio_ap_irq_disable(q);
- put_device(dev);
- }
}

int vfio_ap_mdev_reset_queue(unsigned int apid, unsigned int apqi,
@@ -1302,3 +1269,38 @@ void vfio_ap_mdev_unregister(void)
{
mdev_unregister_device(&matrix_dev->device);
}
+
+int vfio_ap_mdev_probe_queue(struct ap_queue *queue)
+{
+ struct vfio_ap_queue *q;
+
+ q = kzalloc(sizeof(*q), GFP_KERNEL);
+ if (!q)
+ return -ENOMEM;
+
+ mutex_lock(&matrix_dev->lock);
+ dev_set_drvdata(&queue->ap_dev.device, q);
+ q->apqn = queue->qid;
+ q->saved_isc = VFIO_AP_ISC_INVALID;
+ hash_add(matrix_dev->qtable, &q->qnode, q->apqn);
+ mutex_unlock(&matrix_dev->lock);
+
+ return 0;
+}
+
+void vfio_ap_mdev_remove_queue(struct ap_queue *queue)
+{
+ struct vfio_ap_queue *q;
+ int apid, apqi;
+
+ mutex_lock(&matrix_dev->lock);
+ q = dev_get_drvdata(&queue->ap_dev.device);
+ dev_set_drvdata(&queue->ap_dev.device, NULL);
+ apid = AP_QID_CARD(q->apqn);
+ apqi = AP_QID_QUEUE(q->apqn);
+ vfio_ap_mdev_reset_queue(apid, apqi, 1);
+ vfio_ap_irq_disable(q);
+ hash_del(&q->qnode);
+ kfree(q);
+ mutex_unlock(&matrix_dev->lock);
+}
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index f46dde56b464..e1f8c82cc55d 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -18,6 +18,7 @@
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/kvm_host.h>
+#include <linux/hashtable.h>

#include "ap_bus.h"

@@ -43,6 +44,7 @@ struct ap_matrix_dev {
struct list_head mdev_list;
struct mutex lock;
struct ap_driver *vfio_ap_drv;
+ DECLARE_HASHTABLE(qtable, 8);
};

extern struct ap_matrix_dev *matrix_dev;
@@ -90,8 +92,6 @@ struct ap_matrix_mdev {

extern int vfio_ap_mdev_register(void);
extern void vfio_ap_mdev_unregister(void);
-int vfio_ap_mdev_reset_queue(unsigned int apid, unsigned int apqi,
- unsigned int retry);

struct vfio_ap_queue {
struct ap_matrix_mdev *matrix_mdev;
@@ -99,6 +99,10 @@ struct vfio_ap_queue {
int apqn;
#define VFIO_AP_ISC_INVALID 0xff
unsigned char saved_isc;
+ struct hlist_node qnode;
};
-struct ap_queue_status vfio_ap_irq_disable(struct vfio_ap_queue *q);
+
+int vfio_ap_mdev_probe_queue(struct ap_queue *queue);
+void vfio_ap_mdev_remove_queue(struct ap_queue *queue);
+
#endif /* _VFIO_AP_PRIVATE_H_ */
--
2.21.1