Open-IOV vGPU-IO: host-side GSP emulation for unmodified NVIDIA guest drivers https://git.vgpu.io/open-iov.git/atom?h=master 2026-10-25T09:57:04+00:00 2026-10-25T09:57:04+00:00 Arthur Hanson Rasmusson arthur@vgpu.io 2026-10-25T09:57:04+00:00 urn:sha1:9813c9b9b6d9fa7e56fe0e77ccd4589fd9e90902 Root-caused the vk_frame client's exact 11.00s gaps: a pure sched_yield + clock_gettime userspace spin inside libnvidia-eglcore's EGL/GL init, waiting for completion slots (u16 at slot+0xe == 0xffff) in /dev/nvidiactl mappings. Guest-side filling of the slot flags lets the client proceed immediately, but vkCreateDevice still fails -4: with the slots filled the client settles into an NVOS54 poll of RM control 0x2080a097 (paramsSize=1168) which our emulation answers with the generic all-zero reply, so the poll never completes. Also captured: sema_push_raw dumps proving the GR channel-init push contains NO release (entry0 decodes 2 methods then zeros; entry2 SET_OBJECT 0xc597 then zeros), and the negative result that neither channelFillGpFifo nor nvWriteGpEntry runs for this channel's kick. New probes: gdbpoll6/gdbu16/gdbfill/gdbwatch/gdbparam/gdbgap3/gdbspin (slot check, flag fill, NVOS54 param dump, backtraces), slotfill{,2}.sh (guest slot watcher), stracevk/fastrun{,2}.sh (strace+perf recipes), find_ring_va.py and vmap_watch2.py (vmap/kcore watchers), README-session74.md.