PF2GUC_RELAY_TO_VF(9)

💅 PF2GUC_RELAY_TO_VF 💅

okay so bestie, welcome to the PF2GUC_RELAY_TO_VF(9) page — it lives in the Kernel API Manual and it's literally just a messenger-girl situation 🧚

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🎀 the vibe (what this thing even is)

This is an H2G message, and the Physical Function (PF) driver uses it to send an embedded VF2PF Relay Message_ over to the VF. that's it, that's the whole job. she's a courier 💌

⚠️ important, no cap: this action message must be sent over CTB as a CTB HXG Message_. like, that's the only way she travels. periodt.

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🦋 the layout (bit-by-bit, she's giving structured ✨)

first, the header dword:

• bit 31 — ORIGIN = GUC_HXG_ORIGIN_HOST_
• bits 30:28 — TYPE = GUC_HXG_TYPE_FAST_REQUEST
• bits 27:16 — MBZ (must be zero, don't be messy 🙈)
• bits 15:0 — ACTION = XE_GUC_ACTION_PF2GUC_RELAY_TO_VF = 0x5101 👑

and then the payload dwords, in order:

1     31:0   VFID - target VF identifier
2     31:0   RELAY_ID - VF/PF message ID
3     31:0   RELAY_DATA1
...
n     31:0   RELAY_DATAx

so like — dword 1 is VFID, the target VF identifier (who's she mailing 💅), dword 2 is RELAY_ID, the VF/PF message ID, and then dword 3 through dword n are RELAY_DATA1 … RELAY_DATAx, however much data you're hauling. the ... is doing so much work there, she contains multitudes 😭

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🌸 SEE ALSO 🌸

go read these next, bestie, i'm obsessed with cross-references honestly 🫶

• Kernel file ./drivers/gpu/drm/xe/abi/guc_actions_sriov_abi.h — the source of truth, the mother document 👑
• GUC2PF_RELAY_FROM_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)

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✨ mwah ✨ that's the whole page. source path is ./drivers/gpu/drm/xe/abi, and she was stamped October 2026 — so like, future icon behaviour honestly 💜 take care of her, she's PF2GUC_RELAY_TO_VF(9) and she ate 💅🔥