param_get_vmidfilter(9)

💖 param_get_vmidfilter — a Kernel API moment 💖

okay so this is param_get_vmidfilter(9), from the Kernel API Manual, and bestie it is literally the function that hands you your z/VM user ID filter. no cap. let's get into it 🫶

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✨ NAME ✨

param_get_vmidfilter — Get z/VM user ID filter 🎀

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🌸 SYNOPSIS 🌸

int param_get_vmidfilter (char *buffer , const struct kernel_param *kp
);

yes she takes two args and returns an int, that's the whole vibe check 💅

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🦋 ARGUMENTS 🦋

• buffer — the buffer where the z/VM user ID filter gets stashed. and here's the tea: the function assumes your buffer size is PAGE_SIZE. like, that's the deal, that's the assumption, respect it 🙈
• kp — a kernel parameter that points at the hvc_iucv_filter array. that's her whole job, she's just the pointer to the array, lowkey iconic 🔥

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⭐ DESCRIPTION ⭐

so what does she actually do? she stores the filter into buffer as a comma-separated list of z/VM user IDs. that's it, that's the function, and she ate 💅

typically, sysfs routines call this function for an attr show — so like, she's the main character behind the scenes when something wants to display the filter. iykyk 👑

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🌈 SEE ALSO 🌈

okay this list is LONG and every single one of these deserves their flowers, so buckle up bestie, we're going through all of them:

• Kernel file ./drivers/tty/hvc/hvc_iucv.c
• hvc_iucv_get_private(9)
• alloc_tty_buffer(9)
• destroy_tty_buffer(9)
• destroy_tty_buffer_list(9)
• hvc_iucv_write(9)
• hvc_iucv_get_chars(9)
• hvc_iucv_queue(9)
• hvc_iucv_send(9)
• hvc_iucv_sndbuf_work(9)
• hvc_iucv_put_chars(9)
• hvc_iucv_notifier_add(9)
• hvc_iucv_cleanup(9)
• tty_outqueue_empty(9)
• flush_sndbuf_sync(9)
• hvc_iucv_hangup(9)
• hvc_iucv_notifier_hangup(9)
• hvc_iucv_dtr_rts(9)
• hvc_iucv_notifier_del(9)
• hvc_iucv_filter_connreq(9)
• hvc_iucv_path_pending(9)
• hvc_iucv_path_severed(9)
• hvc_iucv_msg_pending(9)
• hvc_iucv_msg_complete(9)
• hvc_iucv_alloc(9)
• hvc_iucv_destroy(9)
• hvc_iucv_parse_filter(9)
• hvc_iucv_setup_filter(9)
• param_set_vmidfilter(9)
• hvc_iucv_init(9)
• hvc_iucv_config(9)

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and that's the whole page, periodt 💜 quick cute sign-off: this one lives in ./drivers/tty/hvc and it's dated October 2026 — so like, future vibes only, slay 🧚✨