Open-IOV vGPU-IO: host-side GSP emulation for unmodified NVIDIA guest drivers https://git.vgpu.io/open-iov.git/atom?h=archive%2Fpre-squash 2026-09-23T02:40:26+00:00 2026-09-23T02:40:26+00:00 Arthur Hanson Rasmusson arthur@vgpu.io 2026-09-23T02:40:26+00:00 urn:sha1:f6d450a8be075fdc19a874826e7649ae0149b099 Root cause of the golden-image NV_ERR_NO_MEMORY: STATIC_KGR_GET_CONTEXT_ BUFFERS_INFO (0x20800a32) fell through to the generic zeroed reply, so kgraphicsInitializeDeferredStaticData() stored a 0-byte main ctx buffer size and kgrctxAllocMainCtxBuffer() did a 0-page allocation (mem_desc.c:1353). Serve the TU104 per-engine ctx buffer table (26 engine IDs x 8 GR engines; NV_U32_MAX = unsupported, which the client skips). Second blocker after that: L2 cache-op and TLB-invalidate completion registers. Turing reaches them through the virtual-register window (GPU_VREG_* = BAR0 + sriovState.virtualRegPhysOffset + offset, 0xB80000 for a non-SRIOV virtual GPU): NV_VIRTUAL_FUNCTION_PRIV_MMU_INVALIDATE (0xB830B0, TRIGGER bit31) and the L2 invalidate/dirty-flush set (0x70000-0x70014 and 0xB80F00/0xB80F04). The driver soft-locked spinning in osDevReadReg032 on 0xB830B4 (kgmmuCheckPendingInvalidates_TU102) and timed out in kmemsysDoCacheOp_GM107; auto-clear all of them (both the plain and windowed aliases). Third: re-probe failed with GspStatusQueueInit msgqRxLink timeout because gsp_rm_emu_reset() was not called before a fresh boot, leaving rm->parsed set so the new libos args were never parsed. Reset GSP-RM state on the fresh FWSEC kick. Verified: guest nvidia-smi and nvidia-smi -L both exit 0 (full unload/reload cycle), GPU enumerated as "NVIDIA GeForce RTX 2080 SUPER" with 256MB, no NO_MEMORY / timeouts / soft lockups in the guest. Also add tools/rmq/grctx_oracle.c documenting that the host RM does not expose the ctx-buffer table to userspace (the real values are probed from the ctxsw ucode by GSP-RM), so the emulation serves synthesized sizes.