STRUCT FWCTL_RPC_CXL(9)

💅 struct fwctl_rpc_cxl(9) 💅

okay so bestie, welcome to the <pink>struct fwctl_rpc_cxl</pink> page from the Kernel API Manual — this is the ioctl(FWCTL_RPC) input for CXL, and honestly? it's giving "small struct, big responsibilities" ✨

---

🎀 NAME 🎀

struct fwctl_rpc_cxl — the ioctl(FWCTL_RPC) input for CXL, no cap 💖

---

🦋 SYNOPSIS 🦋

here's the whole vibe, literally verbatim, don't touch a single character:

struct fwctl_rpc_cxl {
    struct {
      __u32 opcode;
      __u32 flags;
      __u32 op_size;
      __u32 reserved1;
    };
    union {
      struct cxl_mbox_get_sup_feats_in get_sup_feats_in;
      struct cxl_mbox_get_feat_in get_feat_in;
      struct cxl_mbox_set_feat_in set_feat_in;
    };
 };

like, look at her. she's built different 🌸

---

👑 Members 👑

okay now the actual members, let's go one by one because every single one matters 🫶

• {unnamed_struct} — anonymous. yes queen, she has no name and that's iconic 💅
• opcode — the CXL mailbox command opcode. this is the "what are we even doing here" field ⭐
• flags — the flags for the command (input). input bestie, remember that ✨
• op_size — size of the input payload. gotta know how much you're feeding her 🍓
• reserved1 — reserved. must be 0s. not vibe-y suggestions, actual requirement, so please don't be that person 🙈
• {unnamed_union} — anonymous again. two anonymous members in one struct? main character energy fr fr 🔥
• get_sup_feats_in — Get Supported Features input 💜
• get_feat_in — Get Feature input 🌈
• set_feat_in — Set Feature input 🎀

---

🌟 SEE ALSO 🌟

go read these too, iykyk:

• Kernel file ./include/uapi/fwctl/cxl.h
• struct fwctl_rpc_cxl_out(9) — yes bestie there's an OUT version too, the sequel ate 💀

ok random but important: reserved1 must be 0s. that's not me being dramatic, that's the manpage. set it to zero and we stay friends 🫶

---

and that's the whole page, you're officially educated 💖 this little gem lives in ./include/uapi/fwctl, dated October 2026 — slay, see you in the group chat ✨🎀🦋