GUC2PF_RELAY_FROM_VF(9)

🎀 GUC2PF_RELAY_FROM_VF 🎀

okay bestie, settle in, because this one's from the Kernel API Manual and it's giving very specific firmware-gossip energy 💅 no cap.

---

✨ NAME ✨

GUC2PF_RELAY_FROM_VF — the lil' message the GuC firmware uses to pass a VF2PF Relay Message along 💌

---

so here's the tea, and I mean literally the whole tea 🫖:

This message is used by the GuC firmware to forward a VF2PF Relay Message received from the Virtual Function (VF) driver to this Physical Function (PF) driver.

and like, it's not a sometimes thing — this message is always sent as a CTB HXG Message. always always. periodt ✨

---

🌈 the bit layout, aka the vibe check

• Row 0 · bit 31 — ORIGIN = GUC_HXG_ORIGIN_GUC_
• Row 0 · bits 30:28 — TYPE = GUC_HXG_TYPE_EVENT
• Row 0 · bits 27:16 — MBZ
• Row 0 · bits 15:0 — ACTION = XE_GUC_ACTION_GUC2PF_RELAY_FROM_VF = 0x5100

slay, that ACTION value is 0x5100, don't forget it, it's iconic to me 🔥

---

🦋 and then the payload, obviously

• 1 · bits 31:0 — VFID — source VF identifier 👀
• 2 · bits 31:0 — RELAY_ID — VF/PF message ID
• 3 · bits 31:0 — RELAY_DATA1
• ...
• n · bits 31:0 — RELAY_DATAx

so yeah, it just keeps going with the data words until it stops, iykyk 🌸

---

👀 SEE ALSO 👀

go read these next, bestie, they're the whole friend group 🫶

• Kernel file ./drivers/gpu/drm/xe/abi/guc_actions_sriov_abi.h
• PF2GUC_RELAY_TO_VF(9)
• GUC2VF_RELAY_FROM_PF(9)
• VF2GUC_RELAY_TO_PF(9)
• GUC2PF_ADVERSE_EVENT(9)
• GUC2PF_VF_STATE_NOTIFY(9)
• VF2GUC_MATCH_VERSION(9)
• PF2GUC_UPDATE_VGT_POLICY(9)
• PF2GUC_UPDATE_VF_CFG(9)
• PF2GUC_VF_CONTROL(9)
• VF2GUC_VF_RESET(9)
• VF2GUC_RESFIX_DONE(9)
• VF2GUC_QUERY_SINGLE_KLV(9)
• PF2GUC_SAVE_RESTORE_VF(9)
• VF2GUC_RESFIX_START(9)

---

and that's the whole page, no crumbs left 💀 mwah 💋

sign-off time: this lil' baddie lives at ./drivers/gpu/drm/xe/abi and it's dated October 2026, and the page you're reading is GUC2PF_RELAY_FROM_VF(9) from the Kernel API Manual, ok bye ily 🎀💖