kvm_pgtable..._clear_young(9)

📦 version 7.3.1, in nixpkgs unstable

💅 kvm_pgtable..._clear_young(9) — like, the Kernel API Manual, bestie ✨

okay so picture this: it's a Kernel API Manual page, the header situation is kvm_pgtable..._clear_young(9), and we're about to get into it. this one is lowkey about checking a flag and maybe wiping it. no cap. let's go 🫶

🌸 NAME 🌸

kvm_pgtable_stage2_test_clear_young — peeks at the access flag in a page-table entry, and if you're feeling spicy, clears it too. that's the whole vibe check 💅

✨ SYNOPSIS ✨

bool kvm_pgtable_stage2_test_clear_young (struct kvm_pgtable *pgt , u64
addr , u64 size , bool mkold );

she returns a bool, she takes four things. iconic signature, honestly 🎀

🦋 ARGUMENTS 🦋

  • pgt — the page-table structure, and it has to be one that was initialised by kvm_pgtable_stage2_init*(). like, don't hand her a random struct and expect magic, bestie 😭
  • addr — the intermediate physical address, aka how you point at the exact page-table entry you're talking about. it's giving "who's that" but for memory 🧚
  • size — how big the address range you're visiting is. yes, you can be nosy about more than one entry at a time 💖
  • mkold — true if the access flag should be cleared. that's it, that's the toggle. she's simple like that 👑

💜 DESCRIPTION 💜

first thing's first: the offset of addr within a page gets straight-up ignored. not her problem, not her business, we don't see it 🙈

what she actually does is test and conditionally clear the access flag for every valid, leaf page-table entry used to translate the range [addr, addr + size). so she walks the whole range, checks the flags, and clears them only when you asked her to. very considered, very methodical, main character energy fr fr 🔥

⚠️ ok this is the important bit, don't skip it: it is the caller's responsibility to invalidate the TLB after calling this function, so the updated permissions are actually visible to the CPUs. she does the page-table part, you do the TLB part. teamwork, babes 🤝 if you skip it, that's on you, not her 💀

🌈 RETURN 🌈

Returns true if any of the visited PTEs had the access flag set. even one. she only needs one little flag to be like "yep, found it" ⭐

💖 SEE ALSO 💖

the whole friend group, assembled 🫶 and also the kernel file ./arch/arm64/include/asm/kvm_pgtable.h:

and that's the whole page, bestie 💫 shoutout to ./arch/arm64/include/asm for hosting her, October 2026 for the timestamp, and kvm_pgtable..._clear_young(9) for being the name on the door 🎀 go forth, clear some flags, flush that TLB, and slay 💅✨

📦 where this page comes from