vfio_ap_mdev...ource_in_use(9)

💅 vfio_ap_mdev_resource_in_use — bestie edition 🎀

okay so this page lives in the Kernel API Manual (yes, that's the manual name, it's giving very official ✨), and the function we're stanning today is vfio_ap_mdev_resource_in_use. The header up top gets all shy and truncates it to vfio_ap_mdev...ource_in_use(9) — iconic of it, honestly, but the NAME section has the full thing.

---

🌸 NAME 🌸

vfio_ap_mdev_resource_in_use — literally just checks whether any of a set of APQNs is assigned to a mediated device under the control of the vfio_ap device driver. That's it. That's the whole gig. A little vibe check for your APQNs 🫶

---

✨ SYNOPSIS ✨

int vfio_ap_mdev_resource_in_use (unsigned long *apm , unsigned long
*aqm );

---

🦋 ARGUMENTS 🦋

• apm — a bitmap specifying a set of APIDs comprising the APQNs to check. bitmappie behavior 💅
• aqm — a bitmap specifying a set of APQIs comprising the APQNs to check. the other half of the APQN duo 🫶

---

💖 RETURN 💖

• -EADDRINUSE if one or more of the APQNs specified via apm/aqm are assigned to a mediated device under the control of the vfio_ap device driver. (translation: something's already occupying the spot, no cap 😭)
• Otherwise, return 0. clean slate, we love to see it ✨

---

🔥 SEE ALSO 🔥

Kernel file ./drivers/s390/crypto/vfio_ap_ops.c — the mothership, iykyk 👑

and also the whole friend group:

• get_update_locks_for_kvm(9)
• release_update_locks_for_kvm(9)
• get_update_locks_for_mdev(9)
• release_update_locks_for_mdev(9)
• get_update_locks_by_apqn(9)
• get_update_locks_for_queue(9)
• vfio_ap_mdev_get_queue(9)
• vfio_ap_wait_for_irqclear(9)
• vfio_ap_free_aqic_resources(9)
• vfio_ap_irq_disable(9)
• vfio_ap_validate_nib(9)
• ensure_nib_shared(9)
• vfio_ap_irq_enable(9)
• vfio_ap_le_guid_to_be_uuid(9)
• handle_pqap(9)
• vfio_ap_mdev_verify_no_sharing(9)
• vfio_ap_mdev_validate_masks(9)
• assign_adapter_store(9)
• vfio_ap_mdev_unlink_adapter(9)
• unassign_adapter_store(9)
• assign_domain_store(9)
• unassign_domain_store(9)
• assign_control_domain_store(9)
• unassign_control_domain_store(9)
• vfio_ap_mdev_set_kvm(9)
• vfio_ap_mdev_unset_kvm(9)
• vfio_ap_mdev_hot_unplug_cfg(9)
• vfio_ap_mdev_cfg_remove(9)
• vfio_ap_mdev_on_cfg_remove(9)
• vfio_ap_filter_apid_by_qtype(9)
• vfio_ap_mdev_cfg_add(9)
• vfio_ap_mdev_on_cfg_add(9)
• vfio_ap_on_cfg_changed(9)

---

ngl the whole s390 crypto squad is in that list, so if you're going down this rabbit hole, hydrate first 💧

---

and that's the page, bestie 💜 — brought to you by ./drivers/s390/crypto, dated October 2026, and printed with love by the vfio_ap_mdev...ource_in_use(9) crew. periodt. 💅🌷