[PATCH v1 03/24] s390/vfio-ap: Provide access to queue objects and related info

Anthony Krowiak
2026-03-25T21:02:05Z

Provide the following:

1. A function that returns a struct vfio_ap_queue object representing a
queue that is bound to the vfio_ap device driver and is assigned to an
mdev

2. A function that returns the number of queues that are or will be passed
through to a guest when the mdev is attached to a guest.

There is already a function for #1; however, it is a static function in
drivers/s390/crypto/vfio_ap_ops.c. The function will be defined in the
drivers/s390/crypto/vfio_ap_private.h file and made non-static. Note that
it would probably make sense to ensure that the mdevs_lock is held for
this function, so a call to lockdep_assert_held(&matrix_dev->mdevs_lock)
will be added to the function implementation.

Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_ops.c | 20 +++++++++++++++++---
drivers/s390/crypto/vfio_ap_private.h | 4 ++++
2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index ef3101f6865e..cd85866b81a0 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -203,12 +203,12 @@ static inline void get_update_locks_for_queue(struct vfio_ap_queue *q)
* Return: the pointer to the vfio_ap_queue struct representing the queue or
* NULL if the queue is not assigned to @matrix_mdev
*/
-static struct vfio_ap_queue *vfio_ap_mdev_get_queue(
- struct ap_matrix_mdev *matrix_mdev,
- int apqn)
+struct vfio_ap_queue *vfio_ap_mdev_get_queue(struct ap_matrix_mdev *matrix_mdev, int apqn)
{
struct vfio_ap_queue *q;

+ lockdep_assert_held(&matrix_dev->mdevs_lock);
+
hash_for_each_possible(matrix_mdev->qtable.queues, q, mdev_qnode,
apqn) {
if (q && q->apqn == apqn)
@@ -2098,6 +2098,20 @@ static void vfio_ap_mdev_request(struct vfio_device *vdev, unsigned int count)
release_update_locks_for_mdev(matrix_mdev);
}

+int vfio_ap_mdev_get_num_queues(struct ap_matrix *ap_matrix)
+{
+ unsigned long apid, apqi;
+ int num_queues = 0;
+
+ lockdep_assert_held(&matrix_dev->mdevs_lock);
+
+ for_each_set_bit_inv(apid, ap_matrix->apm, AP_DEVICES)
+ for_each_set_bit_inv(apqi, ap_matrix->aqm, AP_DOMAINS)
+ num_queues++;
+
+ return num_queues;
+}
+
static int vfio_ap_mdev_get_device_info(unsigned long arg)
{
unsigned long minsz;
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index 39c85bab05c3..d66586825ef4 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -153,6 +153,10 @@ struct vfio_ap_queue {
struct ap_tapq_hwinfo hwinfo;
};

+struct vfio_ap_queue *vfio_ap_mdev_get_queue(struct ap_matrix_mdev *matrix_mdev, int apqn);
+
+int vfio_ap_mdev_get_num_queues(struct ap_matrix *ap_matrix);
+
int vfio_ap_mdev_register(void);
void vfio_ap_mdev_unregister(void);

--
2.52.0