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diff --git a/wiki/BAR-Emulation-Specification.md b/wiki/BAR-Emulation-Specification.md index b8a46c3..a963dcd 100644 --- a/wiki/BAR-Emulation-Specification.md +++ b/wiki/BAR-Emulation-Specification.md @@ -1,7 +1,14 @@ # BAR Emulation Specification (GSP 570.144W) +> **Historical document — superseded.** The `BAR_TRAP` RPC (type 0x0A) +> described here is **not used**: in emulation mode it returns `-ENOTSUPP`, +> and BAR access is synchronous MMIO through the BAR shadow. Guest-visible BAR +> windows are BAR0 (16 MB register MMIO), BAR1 (256 MB VRAM aperture) and +> BAR3 (instance window). Canonical documentation: +> [`../docs/03-architecture/06-host-module-and-hybrid-model.md`](../docs/03-architecture/06-host-module-and-hybrid-model.md). + ## Overview -The GSP firmware implements BAR (Base Address Register) emulation for virtual GPU (vGPU) through the **BAR_TRAP** RPC (type 0x0A). The main handler at **0x04CB8188** (40 KB) manages BAR1 aperture, forced access, and memory backing. +The GSP firmware implements BAR (Base Address Register) emulation for virtual GPU (vGPU) through the **BAR_TRAP** RPC (type 0x0A). The main handler at **0x04CB8188** (40 KB) manages BAR1 aperture, forced access, and memory backing. **This RPC is not used by the live path**: in emulation mode `BAR_TRAP` returns `-ENOTSUPP`; guest BAR access is handled synchronously as MMIO through the BAR shadow (`../kernel/bar_emulation.c`), not via an RPC. ## Key Addresses |