kvm_s390_gisc_unregister(9)

📦 version 7.3.1, in nixpkgs unstable

💅 kvm_s390_gisc_unregister(9)

ok so bestie, welcome to the Kernel API Manual entry for kvm_s390_gisc_unregister — yes it's a whole mouthful, yes it's about s390 KVM, and yes we are gonna get through it together 🫶

✨ NAME ✨

kvm_s390_gisc_unregister — unregister a guest ISC 🎀

🌸 SYNOPSIS 🌸

int kvm_s390_gisc_unregister (struct kvm *kvm , u32 gisc );

like, that's the whole vibe. one function, two args, int coming back atcha 💖

🦋 ARGUMENTS 🦋

  • kvm — the kernel vm you're working with 💜
  • gisc — the guest interruption sub class to register 🌸 (and yes the manpage literally says "register" on the *un*register function, we don't make the rules, we just report them 😭)

👑 DESCRIPTION 👑

ok so what does it actually do:

  • it reduces the vm specific alert mask to use — that's the main character move of this function ✨
  • the effective IAM mask in the GISA gets updated as well, but only in the case where the GISA is not part of the GIB alert list 🌈
  • and if it does need updating, it'll be updated latest when the IAM gets restored by gisa_get_ipm_or_restore_iam 💫

that's it. that's the whole plot. no cap 🧚

⭐ RETURN ⭐

on the happy path you get back:

  • the nonspecific ISC (NISC) — the one the gib alert mechanism has registered with the channel subsystem 👑

and when things go sideways (dramatic but accurate):

  • -ENODEV — in case the vm uses no GISA 💀
  • -ERANGE — in case the guest ISC is invalid 🚫
  • -EINVAL — in case the guest ISC is not registered 🙈
fr fr check these return values, bestie — -EINVAL lowkey means you handed it something it never knew about in the first place 😭

🍓 SEE ALSO 🍓

Kernel file ./arch/s390/kvm/s390/interrupt.c — plus these iconic little functions:

go read them, iykyk 🦋

and that's the page!! source/version is ./arch/s390/kvm/s390, dated October 2026 — periodt, slay, go unregister some guest ISCs responsibly 💅✨🎀

📦 where this page comes from