cp_update_scsw(9)

🌸 NAME 🌸

okay so this is cp_update_scsw(9) from the Kernel API Manual, and it does exactly one iconic little job: update scsw for a channel program. 💅 no cap.

✨ SYNOPSIS ✨

void cp_update_scsw (struct channel_program *cp , union scsw *scsw );

🎀 ARGUMENTS 🎀

• cp — the channel_program you're performing the operation on. main character energy, obviously.
• scsw — the I/O results of the channel program, and also the target that gets updated. it's giving dual-purpose queen. 👑

🦋 DESCRIPTION 🦋

okay so bestie, scsw contains the I/O results of the channel program that cp points to. but here's the plot twist 😭: what scsw->cpa stores is a host physical address, which is literally meaningless for the guest — and the guest is the one waiting for the I/O results. rude, honestly.

this function updates scsw->cpa to its corresponding guest physical address. that's the whole glow-up. ✨

💜 SEE ALSO 💜

• Kernel file ./drivers/s390/cio/vfio_ccw_cp.c
• ccwchain_calc_length(9)
• cp_init(9)
• cp_free(9)
• cp_prefetch(9)
• cp_get_orb(9)
• cp_iova_pinned(9)

mwah 💋 this cutie comes from source/version ./drivers/s390/cio, dated October 2026, and it's cp_update_scsw(9) — periodt. 🫶🌷