HYPER-V(4)

💖 HYPER-V(4) 💖

ok so this is the manual for hv_kvp, a.k.a. the Hyper-V Key Value Pair Driver, and yes bestie we're doing kernel interfaces today, sit down, hydrate, we're going in 🫶

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✨ NAME ✨

hv_kvp — the Hyper-V Key Value Pair Driver 💅

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🌸 SYNOPSIS 🌸

so if you wanna compile this driver into the kernel (not as a module, into the kernel, we're committing), you drop these lines into the system kernel configuration file:

device hyperv

that's it. that's the whole synopsis. short king energy honestly 👑

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🦋 DESCRIPTION 🦋

okay so what does hv_kvp actually do? bestie, it gives you the ability to store, retrieve, modify and delete key value pairs for FreeBSD guest partitions running on Hyper-V. literally all four of those verbs. the whole CRUD moment.

here's the vibe: Hyper-V lets administrators stash custom metadata in the form of key value pairs inside the FreeBSD guest partition. and how do they poke at it? Windows Powershell scripts, babes. admins use Powershell scripts to add, read, modify and delete those key value pairs. no cap.

the driver itself is bare bones — like, it's giving minimal. it doesn't even do the work, it just forwards requests to its counterpart user mode daemon, hv_kvp_daemon(8). that daemon is the one holding the actual pools of key value pairs and doing the real metadata management. the driver is basically the group chat relay and the daemon is the one who actually replies 😭 iconic division of labour.

and btw the same driver and daemon combination is also what you use to set and get IP addresses from a FreeBSD guest. same duo, second job, they're booked and busy.

the set functionality — this one's lowkey the main character. it's particularly useful when the FreeBSD guest is assigned a static IP address and gets failed over from one Hyper-V host to another. after failover, Hyper-V uses the set IP functionality to automatically update the FreeBSD guest's IP address back to its original static value. like it just snaps back into place. slay. 🔥

the get IP functionality — meanwhile, this one is used to update the guest IP address over in the Hyper-V management console window. so the console knows what's up. ✨

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🎀 SEE ALSO 🎀

go read these next bestie, they're all in the family:

• hv_ata_pci_disengage(4)
• hv_netvsc(4)
• hv_storvsc(4)
• hv_utils(4)
• hv_vmbus(4)
• hv_kvp_daemon(8)

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👑 HISTORY 👑

support for hv_kvp first appeared in FreeBSD 10.0 💜

and the lore? the driver was developed through a joint effort between Citrix Incorporated, Microsoft Corporation and Network Appliance Incorporated. three companies, one driver, a whole collab album fr fr.

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💖 AUTHORS 💖

FreeBSD support for hv_kvp was first added by the Microsoft BSD Integration Services Team <bsdic@microsoft.com>. thank you for your service 🫶

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and that's the page!! this one came out of the Debian corner of the world, dated September 10, 2013 — yes it's vintage, yes it still ate, we don't talk about it 💅✨ bye bestie, go read your kernel config 🌈