read_guest(9)

📦 version 7.3.1, in nixpkgs unstable

💖 read_guest(9) — bestie edition 💖

okay so you're in the Kernel API Manual and the page you've pulled up is read_guest(9), and honestly? she's a little legend. let's get into it 🫶

✨ NAME ✨

read_guest — copy data from guest space to kernel space

like, you got data chilling in the guest and you need it over here in the kernel. that's her whole job. no cap. 💅

🌸 SYNOPSIS 🌸

int read_guest (struct kvm_vcpu *vcpu , unsigned long ga , u8 ar , void
*data , unsigned long len );

look at that signature. gorgeous. (yes the spacing is exactly like that, don't @ me, i don't make the rules 🎀)

🦋 ARGUMENTS 🦋

  • vcpu — the virtual cpu, aka the main character of this whole situation 👑
  • ga — guest address, where the data is living rn
  • ar — access register, the little key to the vibes
  • data — destination address in kernel space, where the data is moving to 🏠
  • len — number of bytes to copy, so she knows exactly how much to scoop up

💜 DESCRIPTION 💜

Copy len bytes from ga (guest address) to data (kernel space). that's it, that's the whole thing. she's efficient. she's iconic. she gets it done ✨

The behaviour of read_guest is identical to read_guest_with_key, except that the PSW access key is used instead of an explicit argument. so same energy, different key delivery system. iykyk 🔑

🍓 SEE ALSO 🍓

the whole friend group, fr fr:

(note that kvm_s390_logical_to_effective(9) shows up twice in the original list — yes bestie, twice. she said "i'm important" and honestly? valid 🧚)

okay final thing — this page comes from ./arch/s390/kvm/s390 and it's dated October 2026, so jot that down if you're citing her. stay hydrated, read your guest memory safely, and slay 💖🌈⭐

love u, bye 🎀

📦 where this page comes from