xenbus_unmap_ring(9)

💅 xenbus_unmap_ring — bestie edition

okay so you're reading the xenbus_unmap_ring(9) page from the Kernel API Manual and honestly? she's a short one, so we can absolutely get through this together 🫶

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✨ NAME ✨

xenbus_unmap_ring — unmap memory from another domain. literally exactly what it says on the tin, no plot twist 💖

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✨ SYNOPSIS ✨

int xenbus_unmap_ring (struct xenbus_device *dev , grant_handle_t
*handles , unsigned int nr_handles , unsigned long *vaddrs );

she takes four things and gives you back an int, that's the whole vibe check ✨

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✨ ARGUMENTS ✨

• dev — the xenbus device, your main character 🎀
• handles — the grant handle array, i.e. your little collection of handles 🦋
• nr_handles — how many handles are actually in that array, no cap, count them properly 🧚
• vaddrs — the addresses you want to unmap 🌸

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✨ DESCRIPTION ✨

so what she does is: unmap memory in this domain that was imported from another domain. that's it. that's the whole description. she's efficient, she's iconic, she doesn't do small talk 💅🔥

like, you brought memory in from somewhere else, and now you're sending it back. the way that closure is a whole concept 👑

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✨ RETURN ✨

• 0 on success (slay 💖)
• GNTST_* on error 😭

if you want the full deets on those error codes, go look at xen/include/interface/grant_table.h — that's where they live, iykyk 🍓

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✨ SEE ALSO ✨

Kernel file ./drivers/xen/xenbus/xenbus_client.c, plus the whole friend group:

• xenbus_watch_path(9)
• xenbus_watch_pathfmt(9)
• xenbus_switch_state(9)
• xenbus_dev_error(9)
• xenbus_dev_fatal(9)
• xenbus_map_ring_valloc(9)
• xenbus_unmap_ring_vfree(9)
• xenbus_read_driver_state(9)

go read them, they're all part of the same era 💜🌈

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and that's the page!! this one lives at ./drivers/xen/xenbus, dated October 2026, and she answers to the name xenbus_unmap_ring(9). mwah, go unmap some memory responsibly 💋✨