assign_control_domain_store(9)

🎀 assign_control_domain_store(9) 🎀

okay bestie, welcome to the Kernel API Manual page for assign_control_domain_store(9) — yes, the manual name is right there near the top, because we are organized and iconic like that 💅✨

🌸 NAME 🌸

assign_control_domain_store — parses the domain ID from @buf and sets the corresponding bit in the mediated matrix device's ADM. that's the assignment vibe, no cap 🦋

✨ SYNOPSIS ✨

       ssize_t assign_control_domain_store (struct device *dev , struct
       device_attribute *attr , const char *buf , size_t count );

💅 ARGUMENTS 💅

• dev — the matrix device. main character energy tbh 👑
• attr — the mediated matrix device's assign_control_domain attribute. yes, that whole attribute situation ✨
• buf — a buffer containing the domain ID to be assigned. the ID lives here, bestie 📦
• count — the number of bytes in buf. byte-counting queen behavior 🔢

🎀 RETURN 🎀

on success it gives you the number of bytes processed — but only if the domain ID is valid. otherwise, it returns one of the following errors:

• -EINVAL — the ID is not a number 💀
• -ENODEV — the ID exceeds the maximum value configured for the system 😭

🦋 SEE ALSO 🦋

Kernel file: ./drivers/s390/crypto/vfio_ap_ops.c

these related pages are the friend group, go say hi 🫶

• 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)
• release_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)
• unassign_control_domain_store(9)
• vfio_ap_mdev_set_kvm(9)
• vfio_ap_mdev_unset_kvm(9)
• vfio_ap_mdev_resource_in_use(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)

mwah 💋 source/version + date sign-off: ./drivers/s390/crypto, dated October 2026, for assign_control_domain_store(9). that's the whole page, bestie — slay and stay safe 🌈🫶