xenbus_map_ring_valloc(9)

📦 version 7.3.1, in nixpkgs unstable

💅 xenbus_map_ring_valloc 💅

okay so bestie, welcome to the xenbus_map_ring_valloc(9) page — it lives in the Kernel API Manual and honestly it's giving "glue code that carries the whole vibe" energy. no cap.

✨ SYNOPSIS ✨

int xenbus_map_ring_valloc (struct xenbus_device *dev , grant_ref_t
*gnt_refs , unsigned int nr_grefs , void **vaddr );

like, look at her. four params, one int return, zero drama. 🎀

🌸 ARGUMENTS 🌸

  • dev — the xenbus device, aka the main character of this whole operation 🫶
  • gnt_refs — a grant reference array. yes, an array, plural, she brought friends
  • nr_grefs — the number of grant references. count 'em, that's how many pages we're dealing with 💅
  • vaddr — a pointer to the address that gets filled out by the mapping. it's an output, she gets written to, iykyk

🦋 DESCRIPTION 🦋

so here's the tea: this function maps nr_grefs pages of memory into this domain, snagged from another domain's grant table. cross-domain friendship bracelet behavior fr fr. 🔥

what xenbus_map_ring_valloc actually does, step by step, no skipping:

  1. allocates nr_grefs pages of virtual address space ✨
  2. maps the pages to that address
  3. sets *vaddr to that address

that's the whole glow-up. iconic.

⚠️ ok now the important part, bestie, don't scroll past this: if an error is returned, the device will switch to XenbusStateClosing and the error message will be saved in XenStore. so yeah, failure isn't silent, it leaves receipts in XenStore 😭

⭐ RETURN ⭐

0 on success or -errno on error. that's it, that's the whole mood. simple queen behavior. 👑

🌈 SEE ALSO 🌈

she does not work alone, she has a whole friend group in the kernel file ./drivers/xen/xenbus/xenbus_client.c:

and that's the page!! 💖 this lil slice of ./drivers/xen/xenbus is dated October 2026 and she ate, no crumbs. go map some rings, bestie, you got this 🧚‍♀️🦋💜

📦 where this page comes from