[PATCH v10 02/16] s390/vfio-ap: use new AP bus interface to search for queue devices

Tony Krowiak
2020-08-21T19:56:02Z

This patch refactor's the vfio_ap device driver to use the AP bus's
ap_get_qdev() function to retrieve the vfio_ap_queue struct containing
information about a queue that is bound to the vfio_ap device driver.
The bus's ap_get_qdev() function retrieves the queue device from a
hashtable keyed by APQN. This is much more efficient than looping over
the list of devices attached to the AP bus by several orders of
magnitude.

Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reported-by: kernel test robot <lkp@intel.com>
---
drivers/s390/crypto/vfio_ap_drv.c | 27 ++-------
drivers/s390/crypto/vfio_ap_ops.c | 86 +++++++++++++++------------
drivers/s390/crypto/vfio_ap_private.h | 8 ++-
3 files changed, 59 insertions(+), 62 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
index f4ceb380dd61..24cdef60039a 100644
--- a/drivers/s390/crypto/vfio_ap_drv.c
+++ b/drivers/s390/crypto/vfio_ap_drv.c
@@ -53,15 +53,9 @@ 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);
}

/**
@@ -72,18 +66,9 @@ 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)
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index e0bde8518745..ad3925f04f61 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -26,43 +26,26 @@

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
+ * vfio_ap_get_queue: Retrieve a queue with a specific APQN.
* @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.
+ * Retrieve a queue with a specific APQN from the AP queue devices attached to
+ * the AP bus.
*
- * Returns the pointer to the associated vfio_ap_queue
+ * Returns the pointer to the vfio_ap_queue with the specified APQN, or NULL.
*/
-static struct vfio_ap_queue *vfio_ap_get_queue(
- struct ap_matrix_mdev *matrix_mdev,
- int apqn)
+static struct vfio_ap_queue *vfio_ap_get_queue(unsigned long apqn)
{
+ struct ap_queue *queue;
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))
+ queue = ap_get_qdev(apqn);
+ if (!queue)
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);
+ q = dev_get_drvdata(&queue->ap_dev.device);
+ put_device(&queue->ap_dev.device);

return q;
}
@@ -144,7 +127,7 @@ static void vfio_ap_free_aqic_resources(struct vfio_ap_queue *q)
* Returns if ap_aqic function failed with invalid, deconfigured or
* checkstopped AP.
*/
-struct ap_queue_status vfio_ap_irq_disable(struct vfio_ap_queue *q)
+static struct ap_queue_status vfio_ap_irq_disable(struct vfio_ap_queue *q)
{
struct ap_qirq_ctrl aqic_gisa = {};
struct ap_queue_status status;
@@ -293,10 +276,11 @@ 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 */
@@ -1116,20 +1100,15 @@ 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,
- unsigned int retry)
+static int vfio_ap_mdev_reset_queue(unsigned int apid, unsigned int apqi,
+ unsigned int retry)
{
struct ap_queue_status status;
int retry2 = 2;
@@ -1302,3 +1281,34 @@ 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;
+
+ dev_set_drvdata(&queue->ap_dev.device, q);
+ q->apqn = queue->qid;
+ q->saved_isc = VFIO_AP_ISC_INVALID;
+
+ 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);
+ 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..a2aa05bec718 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"

@@ -90,8 +91,6 @@ 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;
@@ -100,5 +99,8 @@ struct vfio_ap_queue {
#define VFIO_AP_ISC_INVALID 0xff
unsigned char saved_isc;
};
-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