Open-IOV vGPU-IO: host-side GSP emulation for unmodified NVIDIA guest drivers https://git.vgpu.io/open-iov.git/atom?h=gr-forwarding 2026-09-26T07:07:57+00:00 2026-09-26T07:07:57+00:00 Arthur Hanson Rasmusson arthur@vgpu.io 2026-09-26T07:07:57+00:00 urn:sha1:b84c6dee395dfad6d17b454f83f760053375f791 2026-09-23T15:46:33+00:00 Arthur Hanson Rasmusson arthur@vgpu.io 2026-09-23T15:46:33+00:00 urn:sha1:5c47eacbe01f9353f2c21d96e1a3eb15a63fd991 - GSP_RM_ALLOC: echo the request payload back with status forced to NV_OK. The kernel driver copies the reply params over the caller's params buffer using the class-expected size, so a zeroed reply smashed libcuda's stack (SIGSEGV at the engine-registration continuation); echoing makes the copy-back idempotent. - CE_GET_PHYSICAL_CAPS / CE_GET_ALL(_PHYSICAL)_CAPS: report sysmem, P2P and BL copy caps and mark the GR-synchronous CE (GRCE, COPY0). Without a GRCE the client's context walk ends with an empty secondary-engine record and the engine RM alloc is issued with class 0 (rejected -> cuCtxCreate fails). - TU104 engine table: CE0 shares the GR PBDMA ids (the driver's GR/GRCE runqueue validation requires it), plus an entry for the async copy engine (COPY14) advertised in the GSP static info engine caps. - tools/guest-diag/ioctl_trace: decode the RM status fields of alloc, control and free so the first failing driver call is visible in traces. gitignore: keep the CUDA analysis scratch tree (incl. WORKING-HERE.md) local. 2026-09-23T11:05:45+00:00 Arthur Hanson Rasmusson arthur@vgpu.io 2026-09-23T11:05:45+00:00 urn:sha1:54ca82d81bacb56197a607d0039ca6a015f5ac44 Analysis tooling for debugging CUDA execution in Open-IOV guests: - userspace/cuda/570.144/: fetch a library from a running guest (nc), objdump helpers, crash ip -> file vaddr + symbol mapping, and Ghidra headless import/analysis/decompile scripts (project kept so single functions decompile in seconds). The purpose is debugging correctness and performance of CUDA in Open-IOV VMs (not a reimplementation); extracted binaries and decompiled output are gitignored. - tools/guest-diag/ioctl_trace.c: ptrace tracker for the NVIDIA driver ioctls of a child (libcuda issues raw syscalls, so LD_PRELOAD sees nothing). Decodes RM_ALLOC (class) and RM_CONTROL (cmd) arguments; this is how the cuCtxCreate crash sequence was captured. - tools/test/cuda_drv_test.c: unbuffered + per-call markers so a crash identifies the CUDA call it happened in.