ibmvmc_rem_buffer(9)

💅 ibmvmc_rem_buffer — Remove Buffer ✨

Okay bestie, so this is a kernel API manual page — <italic>ibmvmc_rem_buffer</italic> from section 9 (the kernel API section, iykyk) 🎀. It's giving "hypervisor wants its buffer back" energy, and honestly? Iconic. Let's get into it.

---

🌸 SYNOPSIS 🌸

int ibmvmc_rem_buffer (struct crq_server_adapter *adapter , struct
ibmvmc_crq_msg *crq );

That's the whole signature, no cap. Returns an int, takes two pointers, we move 💅.

---

🦋 ARGUMENTS 🦋

• adapter — the crq_server_adapter struct. Yeah, that one. It's the CRQ server adapter, bestie.
• crq — the ibmvmc_crq_msg struct. Also exactly what it sounds like.

---

💖 DESCRIPTION 💖

So this message is literally requesting that an HMC buffer get transferred from management partition ownership over to hypervisor ownership 🔥. Big handoff moment.

But here's the tea: the management partition might not be able to satisfy the request at a particular point in time — specifically if all its buffers are in use. So awkward 🙈. The management partition needs a depth of at least one inbound buffer so that management application commands can actually flow to the hypervisor. So if the hypervisor tries to remove the management partition's last buffer? That's an interface error, periodt. Not allowed. Absolutely not.

The hypervisor is expected to manage buffer usage with the management application directly, and to inform the management partition when buffers may be removed. The typical flow for removing buffers goes like this, bestie ✨:

1. The management application no longer needs a communication path to a particular hypervisor function. That function is closed.
2. The hypervisor and the management application quiesce all traffic to that function. The hypervisor requests a reduction in buffer pool size.
3. The management application acknowledges the reduction in buffer pool size.
4. The hypervisor sends a Remove Buffer message to the management partition, informing it of the reduction in buffers.
5. The management partition verifies it can remove the buffer. This is possible if buffers have been quiesced.

Five steps. Whole little choreography. Kind of obsessed with the teamwork ngl 🫶.

---

⭐ RETURN ⭐

• 0 — Success 🎉
• Non-zero — Failure 😭

---

👑 SEE ALSO 👑

Grab a snack, this list is long and it ate 💀. Kernel file ./drivers/misc/ibmvmc.c plus all of these:

• h_request_vmc(9)
• ibmvmc_handle_event(9)
• ibmvmc_release_crq_queue(9)
• ibmvmc_reset_crq_queue(9)
• crq_queue_next_crq(9)
• ibmvmc_send_crq(9)
• alloc_dma_buffer(9)
• free_dma_buffer(9)
• ibmvmc_get_valid_hmc_buffer(9)
• ibmvmc_get_free_hmc_buffer(9)
• ibmvmc_free_hmc_buffer(9)
• ibmvmc_count_hmc_buffers(9)
• ibmvmc_get_free_hmc(9)
• ibmvmc_return_hmc(9)
• ibmvmc_send_open(9)
• ibmvmc_send_close(9)
• ibmvmc_send_capabilities(9)
• ibmvmc_send_add_buffer_resp(9)
• ibmvmc_send_rem_buffer_resp(9)
• ibmvmc_send_msg(9)
• ibmvmc_open(9)
• ibmvmc_close(9)
• ibmvmc_read(9)
• ibmvmc_poll(9)
• ibmvmc_write(9)
• ibmvmc_setup_hmc(9)
• ibmvmc_ioctl_sethmcid(9)
• ibmvmc_ioctl_query(9)
• ibmvmc_ioctl_requestvmc(9)
• ibmvmc_ioctl(9)
• ibmvmc_add_buffer(9)
• ibmvmc_process_capabilities(9)
• ibmvmc_validate_hmc_session(9)
• ibmvmc_reset(9)
• ibmvmc_reset_task(9)
• ibmvmc_process_open_resp(9)
• ibmvmc_process_close_resp(9)
• ibmvmc_crq_process(9)
• ibmvmc_handle_crq_init(9)
• ibmvmc_handle_crq(9)
• ibmvmc_init_crq_queue(9)

All of them, in the exact order, because we do not skip entries in this house 🏠✨.

---

That's the whole page, bestie. This one lives in ./drivers/misc and it's dated October 2026 — yes, from the future, main character energy fr 💜🧚. Go read the real thing if you want the completely unedited vibe, but you're all caught up now. Love that for you 🍓💅