kvm_mips_restore_hrtimer(9)

📦 version 7.3.1, in nixpkgs unstable

💖 kvm_mips_restore_hrtimer(9) 💖

okay so bestie, welcome to the kvm_mips_restore_hrtimer page from the Kernel API Manual — yes it's a (9) section, yes it's kernel-internal, no you may not skip it, we're doing this together 🫶

✨ NAME ✨

kvm_mips_restore_hrtimer — restores the hrtimer after a gap, and updates the expiry while it's at it. literally the glow-up-your-timer function 💅

🌸 SYNOPSIS 🌸

int kvm_mips_restore_hrtimer (struct kvm_vcpu *vcpu , ktime_t before ,
u32 count , int min_drift );

that's the whole vibe check right there, no cap ✨

🎀 ARGUMENTS 🎀

  • vcpu — the virtual CPU. the main character, obviously 👑
  • before — the time before Count was saved. it's the lower bound of the drift calculation, so think of it as the "no drift earlier than this, bestie" line 🦋
  • count — CP0_Count at the point of restore. the number we're bringing back 🌸
  • min_drift — the minimum amount of drift that's permitted before we bother correcting. and here's the rule, highkey important: must be <= 0 ⚠️

💜 DESCRIPTION 💜

so what this does: it restores the timer from a particular count, and it accounts for drift while doing it. that's the whole point 🎯

you'd use this together with kvm_mips_freeze_timer — like, when a hardware timer is gonna be used for a period of time, but the exact ktime that corresponds to the final Count you have to restore is... not known. yeah. awkward. this function is the friend who steps in 🙈

it's guaranteed that a timer interrupt right after the restore will be handled ✅ — but like, not if CP0_Compare is exactly at count. that specific case should already be handled when the hardware timer state is saved, so don't come for this function about it 💀

also it assumes !kvm_mips_count_disabled(vcpu) — i.e. the guest CP0_Count timer is not stopped. if it is stopped, that's not our problem, that's your problem 🍓

⭐ RETURN ⭐

returns the amount of correction to count_bias due to drift. it's giving "here's your receipt" 🧾✨

🌈 SEE ALSO 🌈

kernel file ./arch/mips/kvm/emulate.c — and honestly, the whole friend group 🔥

this page lives in ./arch/mips/kvm, dated October 2026 — the Kernel API Manual said so, and the manual never lies 💜

okay that's the whole page, you ate it, mwah 💋 periodt 🌈

📦 where this page comes from