Open-IOV vGPU-IO: host-side GSP emulation for unmodified NVIDIA guest drivers https://git.vgpu.io/open-iov.git/atom?h=reg-probe 2026-09-25T05:48:37+00:00 2026-09-25T05:48:37+00:00 Arthur Hanson Rasmusson arthur@vgpu.io 2026-09-25T05:48:37+00:00 urn:sha1:93769b1e19b4ce2cf1738d72e600adc5a9ef315b - Add expected_sem_payload tracking to svc_channel for CE channels - Implement svc_rescue_push_page() to scan guest RAM for push with expected semaphore release when VA translation fails - Add svc_init_expected_payload() to initialize expected payload from pool - Add rate-limited logging of distinct stalled VAs (svc_log_stalled_va) - Advance expected_sem_payload on successful push decode - Pushes SEMA_MAP_MAX to 65536, SVC_PIN_SLOTS to 32768 for scale 2026-09-24T14:01:22+00:00 Arthur Hanson Rasmusson arthur@vgpu.io 2026-09-24T14:01:22+00:00 urn:sha1:cc2c2ab40af45e3a14e93b87e4988909303f8a95 The vidmem window convention turns any VA above the window base into a vidmem offset, but the CUDA client's GPU semaphores are sysmem objects mapped into its address space at those same VAs. A release applied through the convention therefore landed in the vidmem shadow instead of the page the client polls, and the completion was silently lost: the libcuda tracker it waits on never advanced. Semaphore reads and writes now use trusted translations only (pins, learned cache, discovered map, page walks), so an unresolved semaphore is counted as a miss and stays visible instead of corrupting a shadow. tools/guest-diag/trkinfo.py dumps the libcuda tracker the client spins on: the tracker object behind p+0x9410, the semaphore object it references, the u32 semaphore memory it polls (a /dev/nvidiactl mapping backed by guest RAM) and the VMA that memory lives in.