STRUCT CXL_MAILBOX(9)

💖 NAME 💖

struct cxl_mailbox — the whole vibe/context container for CXL mailbox operations ✨ (and yes bestie, this is the struct cxl_mailbox(9) page, straight out of the Kernel API Manual, section 9, no cap 🫶)

🌸 SYNOPSIS 🌸

okay so here's literally the whole struct, look at her go 👑

struct cxl_mailbox {
    struct device *host;
    unsigned long enabled_cmds[BITS_TO_LONGS( CXL_MEM_COMMAND_ID_MAX)];
    unsigned long exclusive_cmds[BITS_TO_LONGS(CXL_MEM_COMMAND_ID_MAX)];
    size_t payload_size;
    struct mutex mbox_mutex;
    struct mutex feat_mutex;
    struct rcuwait mbox_wait;
    int (*mbox_send)(struct cxl_mailbox *cxl_mbox, struct cxl_mbox_cmd *cmd);
    enum cxl_features_capability feat_cap;
};

🎀 MEMBERS 🎀

meet the cast, they're all main characters tbh 💅

• host — the device that hosts the mailbox. like, the one whose name is on the lease 😌
• enabled_cmds — the mailbox commands that the driver has enabled. these are the ones that got the green light 🟢
• exclusive_cmds — the mailbox commands that are exclusive to the kernel. kernel-only, invite-only, iykyk 🔒
• payload_size — size of the space for the payload (CXL 3.1 8.2.8.4.3 Mailbox Capabilities Register). yes that's the exact citation, go read it bestie 📖
• mbox_mutex — mutex that protects the device mailbox and the firmware. one at a time, we do NOT do chaos here 🚦
• feat_mutex — serializes the multi-part Get/Set Feature transfers. it's giving "line leader energy" so nobody's transfers get tangled 😤
• mbox_wait — an rcuwait for the mailbox. the waiting room, but make it kernel 🌈
• mbox_send — the dev-specific transport for actually transmitting mailbox commands. this is THE messenger fr fr 📨
• feat_cap — the Features capability. the enum cxl_features_capability one, keeping receipts 🧾

💜 SEE ALSO 💜

• Kernel file ./include/cxl/mailbox.h 🦋
• struct cxl_mbox_cmd(9) — go say hi, she's the related icon ✨

ok that's the whole page, you ate that 🍓 no skimming, everything's still here, every member, every mutex, every citation. periodt 💅

and that's a wrap on struct cxl_mailbox(9) — live from ./include/cxl, dated October 2026, mwah 😘💖