STRUCT EFI_MM_COMMUNICATE_HEADER(9)

💖 NAME 💖

okay so bestie, welcome to the Kernel API Manual — today’s main character is struct efi_mm_communicate_header (page vibe: struct efi_mm_communicate_header(9), and yes she’s iconic 💅). She’s the header used for SMM variable communication. periodt. ✨

✨ SYNOPSIS ✨

struct efi_mm_communicate_header {
    efi_guid_t header_guid;
    size_t message_len;
    u8 data[];
 };

💅 Members 💅

• header_guid — header use for disambiguation of content. lowkey her little name tag for figuring out what the content is 🎀
• message_len — length of the message. Does not include the size of the header. no cap.
• data — payload of the message. that’s the actual stuff inside 🍓

🦋 Description 🦋

Defined in the PI spec as EFI_MM_COMMUNICATE_HEADER. To avoid confusion in interpreting frames, the communication buffer should always begin with efi_mm_communicate_header. fr fr, always. 💀

🌈 SEE ALSO 🌈

okay these are her friends, go say hi:

• Kernel file ./drivers/firmware/efi/stmm/mm_communication.h
• struct smm_variable_communicate_header(9)
• struct smm_variable_access(9)
• struct smm_variable_payload_size(9)
• struct smm_variable_getnext(9)
• struct smm_variable_query_info(9)
• struct var_check_property(9)
• struct smm_variable_var_check_property(9)

that’s the whole page, bestie 🫶 source/version: ./drivers/firmware/efi/stmm · date: October 2026 · page tag: struct efi_m...icate_header(9). mwah 💋