cxl_internal_send_cmd(9)

okay so bestie, welcome to cxl_internal_send_cmd(9) 💖 this page lives in the Kernel API Manual and she is literally the backstage pass for mailbox commands — no cap, she's the kernel-internal way to slide a command into the mailbox 🎀

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🎀 NAME 🎀

cxl_internal_send_cmd — kernel internal interface to send a mailbox command ✨

🌸 SYNOPSIS 🌸

int cxl_internal_send_cmd (struct cxl_mailbox *cxl_mbox , struct cxl_mbox_cmd *mbox_cmd );

🦋 ARGUMENTS 🦋

• cxl_mbox — the CXL mailbox context, your main character 🫶
• mbox_cmd — the initialized command you wanna execute, already dressed and ready 💅

✨ CONTEXT ✨

Any context. like, genuinely any. she's flexible like that 🌈

🔥 RETURN 🔥

• %>=0 — number of bytes returned in out 💖
• -E2BIG — payload is too large for the hardware 😭
• -EBUSY — couldn't acquire exclusive mailbox access, someone else is in the group chat 🙈
• -EFAULT — a hardware error occurred 💀
• -ENXIO — command completed, but the device reported an error 😬
• -EIO — unexpected output size 🫠

👑 DESCRIPTION 👑

okay this is the part that matters, so listen up 🍓

Mailbox commands may execute successfully yet the device itself reported an error. two different things!! and while this distinction can be useful for commands from userspace, the kernel will only be able to use results when both are successful. both. not one. both. periodt 🧚

🌈 SEE ALSO 🌈

• Kernel file ./drivers/cxl/core/mbox.c cxl
• mbox(9)
• cxl_payload_from_user_allowed(9)
• cxl_validate_cmd_from_user(9)
• handle_mailbox_cmd_from_user(9)
• cxl_walk_cel(9)
• cxl_enumerate_cmds(9)
• cxl_mem_get_event_records(9)
• cxl_mem_get_partition_info(9)
• cxl_dev_state_identify(9)
• cxl_mem_sanitize(9)

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and that's the whole vibe check 🦋 she lives over in ./drivers/cxl/core, dated October 2026, and she answers to cxl_internal_send_cmd(9) — go read her friends, iykyk 💜