STRUCT AP_MATRIX_MDEV(9)

🎀 struct ap_matrix_mdev(9) 🎀

okay so bestie, welcome to the Kernel API Manual page for struct ap_matrix_mdev — it's giving "the data associated with a matrix mediated device" and honestly? it's a whole vibe. this struct is basically the main character of the vfio_ap world, holding everything the kernel needs to know about one of these bad boys. let's get into it 💅

✨ SYNOPSIS ✨

struct ap_matrix_mdev {
    struct vfio_device vdev;
    struct list_head node;
    struct ap_matrix matrix;
    struct ap_matrix shadow_apcb;
    struct kvm *kvm;
    crypto_hook pqap_hook;
    struct mdev_device *mdev;
    struct ap_queue_table qtable;
    struct eventfd_ctx *req_trigger;
    struct eventfd_ctx *cfg_chg_trigger;
    unsigned long apm_add[BITS_TO_LONGS( AP_DEVICES)];
    unsigned long aqm_add[BITS_TO_LONGS( AP_DOMAINS)];
    unsigned long adm_add[BITS_TO_LONGS( AP_DOMAINS)];
 };

like, that's the whole shape of it. iconic. no notes. 🫶

🌸 Members 🌸

here's the member-by-member breakdown, because every single field matters and we are not skipping any of them:

• vdev — the vfio device 💖
• node — this is what lets the ap_matrix_mdev struct get added onto a list, lowkey doing the social-networking work of the struct world
• matrix — the adapters, usage domains and control domains assigned to the mediated matrix device. the whole assigned squad, basically ✨
• shadow_apcb — the shadow copy of the APCB field of the KVM guest's CRYCB. yes it's a mouthful, no we're not renaming it 🎀
• kvm — the struct holding guest's state
• pqap_hook — the function pointer to the interception handler for the PQAP(AQIC) instruction. it's the bouncer at the club, catching that instruction on the way in 🔥
• mdev — the mediated device
• qtable — table of queues (struct vfio_ap_queue) assigned to the mdev 👑
• req_trigger — eventfd ctx for signaling userspace to return a device
• cfg_chg_trigger — eventfd ctx to signal AP config changed to userspace. so userspace always knows when the AP config shifted, no surprises, we love communication 🦋
• apm_add — bitmap of APIDs added to the host's AP configuration
• aqm_add — bitmap of APQIs added to the host's AP configuration
• adm_add — bitmap of control domain numbers added to the host's AP configuration

ngl bestie, three separate bitmaps for three separate "added to the host's AP configuration" things — APIDs, APQIs, and control domain numbers. keep 'em straight and you're golden 💀

🦋 SEE ALSO 🦋

• Kernel file ./drivers/s390/crypto/vfio_ap_private.h
• struct ap_matrix_dev(9)
• struct ap_matrix(9)
• struct ap_queue_table(9)
• struct vfio_ap_queue(9)

go read those too, iykyk 😭✨

and that's the whole page, bestie!! 💜 this one came to you from the kernel file spot at ./drivers/s390/crypto, dated October 2026, and yeah — that's the struct ap_matrix_mdev(9) page, periodt. 🌈🍓 slay responsibly 🎀