plpks_write_var(9)

💅 plpks_write_var — Kernel API Manual ✨

Okay so bestie, welcome to the plpks_write_var(9) page — it's lowkey a whole vibe, and honestly it's giving "small function, big power." Sit down, grab a strawberry 🍓, and let's get into it.

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✨ NAME ✨

plpks_write_var — Write the specified variable and its data to PLPKS. Periodt. That's the whole job. 💖

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🎀 SYNOPSIS 🎀

int plpks_write_var (struct plpks_var var );

That's it. One arg. We love a minimal queen. 👑

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🦋 ARGUMENTS 🦋

• var — the variable to be written into the PLPKS. Like, this is the thing you're yeeting into the store, bestie, so make it a good one. 🫶

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🔥 DESCRIPTION 🔥

So the H_PKS_WRITE_OBJECT HCALL is the actual main character here — it writes an object into the PLPKS. For this to be a slay and not a flop, the caller must provide a valid component type for the variable, and the signed update policy flag must not be set. No cap, those are the rules. 💅

And now? The part everyone asks about at 2am: possible reasons for the returned errno values. Bestie, there are so many of them. Here's the full set, no skipping, iykyk:

• -ENXIO — if PLPKS is not supported
• -EIO — if PLPKS access is blocked due to the LPAR's state
  • if PLPKS modification is blocked due to the LPAR's state
  • if an error occurred while processing the request
• -EINVAL — if invalid authorization parameter
  • if invalid object label parameter
  • if invalid object label len parameter
  • if invalid or unsupported policy declaration
  • if invalid input data parameter
  • if invalid input data len parameter
• -EPERM — if access is denied
• -ENOMEM — if unable to store the requested object in the space available
• -EBUSY — if unable to handle the request
• -EEXIST — if the object label already exists

Yeah, -EIO and -EINVAL each come with their own little friend group of causes. Read them all before you go blaming the wrong thing 😭

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⭐ RETURN ⭐

On success, 0 is returned — iconic, we love a clean exit 🎉 — and a negative errno if not. F in the chat for the failure case. 💀

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🌈 SEE ALSO 🌈

Kernel file ./arch/powerpc/platforms/pseries/plpks.c

And the rest of the plpks bestie squad, in order:

plpks_get_version(9), plpks_get_objoverhead(9), plpks_get_maxpwsize(9), plpks_get_maxobjectsize(9), plpks_get_maxobjectlabelsize(9), plpks_get_totalsize(9), plpks_get_usedspace(9), plpks_get_supportedpolicies(9), plpks_get_maxlargeobjectsize(9), plpks_get_signedupdatealgorithms(9), plpks_get_wrappingfeatures(9), plpks_get_passwordlen(9), plpks_is_available(9), plpks_signed_update_var(9), plpks_remove_var(9), plpks_wrapping_is_supported(9), plpks_gen_wrapping_key(9), plpks_wrap_object(9), plpks_unwrap_object(9), plpks_read_os_var(9), plpks_read_fw_var(9), plpks_read_bootloader_var(9), plpks_populate_fdt(9), plpks_early_init_devtree(9)

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✨ that's the whole page, bestie ✨ 🧚 This one comes to you from ./arch/powerpc/platforms/pseries, dated October 2026, and it's the plpks_write_var(9) manual page — go forth and write those variables responsibly, mwah 💜🎀🌸