VF2GUC_RESFIX_START(9)

💅 VF2GUC_RESFIX_START

okay so this is a page out of the Kernel API Manual, and honestly? it's a whole little protocol moment. stay with me bestie, it's easier than it looks 🫶

✨ NAME ✨

VF2GUC_RESFIX_START — the vibe-check message a VF sends to the GuC to say "hey, the VF KMD is about to start its post-migration recovery fixups" 🌸

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🦋 DESCRIPTION 🦋

so basically, this action is what the VF uses to inform the GuC that the VF KMD is about to kick off its post-migration recovery fixups. main character announcement energy, fr fr.

⚠️ important: the MARKER you send along with this action must match the MARKER posted in the VF2GUC_RESFIX_DONE message. like, they have to match. no cap. if they don't, that's gonna be a problem 💀

this message must be sent as an MMIO HXG Message.

available since GuC VF compatibility 1.27.0 ✨ (so yes, it's got lore)

🎀 the request bits (what you send) 🎀

• bit 31 — ORIGIN = GUC_HXG_ORIGIN_HOST_
• bits 30:28 — TYPE = GUC_HXG_TYPE_REQUEST_
• bits 27:16 — DATA0 = MARKER — and listen, it can't be zero. like, zero is not it 🙈
• bits 15:0 — ACTION = GUC_ACTION_VF2GUC_RESFIX_START = 0x550F

💖 the response bits (what comes back) 💖

• bit 31 — ORIGIN = GUC_HXG_ORIGIN_GUC_
• bits 30:28 — TYPE = GUC_HXG_TYPE_RESPONSE_SUCCESS_
• bits 27:0 — DATA0 = MBZ

(MBZ = "must be zero", so if you were thinking of putting something cute in there… don't 💅)

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👑 SEE ALSO 👑

kernel file: ./drivers/gpu/drm/xe/abi/guc_actions_sriov_abi.h

and the whole friend group 🫶

• GUC2PF_RELAY_FROM_VF(9)
• 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)

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and that's the whole page, bestie ✨ this one lives down in ./drivers/gpu/drm/xe/abi, dated October 2026, and it's literally titled VF2GUC_RESFIX_START(9). periodt 💅💖