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<title>open-iov.git/kernel/gsp_phys_gpu.h, branch gr-forwarding</title>
<subtitle>Open-IOV vGPU-IO: host-side GSP emulation for unmodified NVIDIA guest drivers
</subtitle>
<id>https://git.vgpu.io/open-iov.git/atom?h=gr-forwarding</id>
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<updated>2026-10-05T17:06:39+00:00</updated>
<entry>
<title>vgsp: guest GR forwarding backend and capture (gsp_phys_gr_forward, default off)</title>
<updated>2026-10-05T17:06:39+00:00</updated>
<author>
<name>Arthur Hanson Rasmusson</name>
<email>arthur@vgpu.io</email>
</author>
<published>2026-10-05T17:06:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.vgpu.io/open-iov.git/commit/?id=ae507e6f241c7e3498728f9d1ffc2d41ede5cd64'/>
<id>urn:sha1:ae507e6f241c7e3498728f9d1ffc2d41ede5cd64</id>
<content type='text'>
Add a default-off guest GR (compute) forwarding path so a guest CUDA
launch submitted on its GR channel can be executed by the physical GR
engine on the ladder channel, with fail-closed fallback to the host CUDA
bridge and the unchanged software release path.

- New module parameter gsp_phys_gr_forward (default 0) and accessor.
- New GR execution gate: boot_stage.rmcall_gr_exec_ok, latched only after
  a real GR submission logs REAL GR SEM OK; the backend refuses while it
  is unset.
- Sema capture: a completed 64-word inline QMD on a trusted, non-replay
  GR decode becomes an svc_gr_cand (push identity, decoded release0,
  parameter/program/pointer fields, up to 8 captured inline-write
  records); the CUDA bridge stays authoritative while the parameter is
  off and is reached in order forward -&gt; bridge -&gt; software release.
- Backend: gsp_phys_backend_guest_gr_submit() maps pages at their own
  guest VAs through fresh Tier-1 small-PT pages/PDE installs or relocates
  inline-captured pages to ladder shadow pages (Tier 2), builds
  SET_OBJECT + the inline-QMD method run + REPORT_SEMAPHORE on the
  compute subchannel, reuses the shared GPFIFO/USERD/doorbell publish
  tail (extracted from the CE submit path, CE bytes unchanged) and polls
  the QMD release and/or module semaphore, draining the epoch-gated
  fault queue on timeout.
- Sema wiring: GR requests reuse the INFLIGHT/hold/deferral machinery so
  the guest channel release applies only on the submit's success/failure
  edge; hold shims preserve the channel engine type.
- Counters and a work_gr state line plus a stats accessor.
- Bounds are fixed: 16 pages, 8 inline records, 64 QMD words; every
  pointer/size checked, pool exhaustion and stale mappings fail closed.
- New ABI layouts pinned with static_asserts.

Compile-only change: no device test performed.
</content>
</entry>
<entry>
<title>vgsp: host CUDA bridge + sema release recovery; greeneye simulator wave</title>
<updated>2026-10-03T18:05:38+00:00</updated>
<author>
<name>Arthur Hanson Rasmusson</name>
<email>arthur@vgpu.io</email>
</author>
<published>2026-10-03T18:05:38+00:00</published>
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<id>urn:sha1:cc79b478843f0230fe6aa8ecd822de7ba71c891e</id>
<content type='text'>
- kernel: gsp_cuda_bridge (QMD launch capture, debugfs job/out/done, param+output resolution cached from inline writes), sema drain fixes (never hold/starve a channel), GR ring autopin + counter autoreg, per-page push reads, counter-derive gate; module builds clean
- tools/cuda-bridge: CUDA driver-API daemon executing mail/vadd kernels on the physical GPU, CUBB2/CBD2 v2 protocol, layout check + self-tests
- tools/guest-diag + tools/cuda-ab: scanner/pin fixes, victory push-only mode
- debug/risc-v-gsp-rm-vm: Phase S simulator wave (GSP device model, boot ladder, triage/re-demo harnesses, docs 30-41), GPGPU-sim scaffolding
- STATE-CURRENT/docs updates
</content>
</entry>
<entry>
<title>kernel: GR context-promote bisection modes 4-17 and server-managed-ctxbuf registry variant; complete vgsp rename; docs/tooling refresh</title>
<updated>2026-10-02T19:13:06+00:00</updated>
<author>
<name>Arthur Hanson Rasmusson</name>
<email>arthur@vgpu.io</email>
</author>
<published>2026-10-02T19:13:06+00:00</published>
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<id>urn:sha1:c9bf1cf098c8ea4daeb3e6c9b274a9025c03045d</id>
<content type='text'>
- gsp_phys_booter: GR promote bisection modes 4-17 (two-phase zero-field VA,
  batched entries, hVirtMemory, bare VA, KMD SKIP_CTXBUFFER_ALLOC channel,
  old-interface GPU_INITIALIZE_CTX, FBMEM context buffer, UVM-faithful PA-only,
  PATCH/PM auxiliary promotes, server-managed no-promote path); PATCH/PM
  geometry queries and buffers; pre-boot SET_REGISTRY profile selection
- gsp_phys_gpu: gsp_phys_rmcall_gr_promote clamp 0..17 and gsp_phys_srv_ctxbuf
  parameter; registry image variant with RMSetClientRMAllocatedCtxBuffer=0
- vgsp rename across kernel, scripts, tools and docs (module vgsp.ko,
  /sys/kernel/debug/vgsp/, vgsp-&lt;subsystem&gt;: log prefixes)
- risc-v-gsp-rm-debugger user-facing rename and docs/CI refresh; guest-diag
  tool updates; README/SBOM/install/Makefile sync

Live status: CE ladder and P6 guest-copy forwarding green; GR engine context
commit still open (all promote shapes accepted or cleanly refused; the channel
stays CTXNOTVALID) - see Handoff-vGPU-IO.md Addendum 21 (local).
</content>
</entry>
<entry>
<title>gsp-phys: GR engine context allocate/map/promote before the GR sem push (default off; live-unverified at promote)</title>
<updated>2026-10-02T14:58:17+00:00</updated>
<author>
<name>Arthur Hanson Rasmusson</name>
<email>arthur@vgpu.io</email>
</author>
<published>2026-10-02T14:58:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.vgpu.io/open-iov.git/commit/?id=2f249817df327f5dcccf0464ad517fa60d6071d3'/>
<id>urn:sha1:2f249817df327f5dcccf0464ad517fa60d6071d3</id>
<content type='text'>
</content>
</entry>
<entry>
<title>gsp-phys: H1 GR ladder - GR0 channel, compute object, GR sem push (default off)</title>
<updated>2026-10-02T12:29:45+00:00</updated>
<author>
<name>Arthur Hanson Rasmusson</name>
<email>arthur@vgpu.io</email>
</author>
<published>2026-10-02T12:29:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.vgpu.io/open-iov.git/commit/?id=fe485080e159c983242d699f4a584659df159818'/>
<id>urn:sha1:fe485080e159c983242d699f4a584659df159818</id>
<content type='text'>
New load-time gsp_phys_rmcall_engine (0=COPY0 default, 1=GR0) parameterizes
the physical ladder: TSG and channel engine_type GR0, one-attempt channel
alloc, TURING_COMPUTE_A engine object (class 0xc5c0, handle 0xcaf0002c),
BIND engineType=1, and a GR method push (SET_OBJECT 0xc5c0 on subchannel 1
plus SET_REPORT_SEMAPHORE) submitted through the existing GPFIFO/USERD
doorbell tail, polling the module semaphore. CE work-forwarding refuses
cleanly while a GR ladder is active. A debugfs trigger re-runs the GR push.
With the parameter at its default the ladder emits byte-identical COPY0
requests (only the state line gains engine=COPY0).

Live (first GR context on the live server): every GR RPC accepted -
channel variant V5, TURING_COMPUTE_A alloc status=0x0 -&gt; hObject=0xcaf0002c,
BIND status=0x0, token=0x1 - and the engine fetched the push (GPGet 0-&gt;1),
but raised a GR exception instead of executing the release:
exceptType=0x20, NOCAT faultingEngine="GR", intr1=0x80000000, no rpc_result
errors. The failure is downstream of all RPCs; no mutating retry was made
and the device released cleanly (WPR2 down, rebound, 5 locks, pstore empty,
same boot). A default-engine control cycle stayed green (REAL COPY OK).
Follow-up: bisect the GR alloc params, the release method D word, and the
method order/context init using the drained GR fault records as the oracle.
</content>
</entry>
<entry>
<title>gsp-phys: P6c C3 - relay forwarded-engine faults to the guest (default off)</title>
<updated>2026-10-02T12:07:10+00:00</updated>
<author>
<name>Arthur Hanson Rasmusson</name>
<email>arthur@vgpu.io</email>
</author>
<published>2026-10-02T12:07:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.vgpu.io/open-iov.git/commit/?id=22105e4ec738ac72d010d930222f6d8e62b4116c'/>
<id>urn:sha1:22105e4ec738ac72d010d930222f6d8e62b4116c</id>
<content type='text'>
New default-off gsp_phys_fault_relay: when a relayed copy times out, the
GSP-RM status queue is drained and the first OS_ERROR_LOG (0x1006) recorded
after the submission's doorbell is decoded (NOCAT corroboration), matched
against the ladder channel's runlist/chid, and delivered to the guest by
writing its channel notifier (info32=exceptType, info16=engine type,
status=0xffff) and posting the channel event. A late-release recheck skips
delivery if the engine actually completed, one delivery per hold, and the
existing software fallback always runs first, so no release or data is lost.

- pure decode helpers extracted from the status printers; prints unchanged
- status-queue walks serialized with a mutex; unmatched 0x1006 records are
  no longer silently dropped
- fault epoch snapshot at the doorbell prevents stale records from matching
- fault counters and faults:/fault_relay: state lines
- default-off gsp_phys_fault_inject debug knob forces the next relayed
  pair's source PTE to zero to produce a real engine fault
- pump notifier latch prevents clobbering a delivered fault

Live: injection run produced a real CE0 FAULT_PTE (0x1f @0x200000), decoded
with errString, chid/runlist matched, notifier delivered, software fallback
applied (applied+fallback==engaged), clean release; the guest RM reacted to
the delivered fault by tearing down its channels (faithful semantics).
Healthy control: faults all zero, relay requested=40 ok=40, smoke
matched=64/64, clean release. Caveat: the auxiliary event post failed
(no_event=1, no MSI-X) and the guest teardown means fault injection is not
smoke-compatible; the parameter stays off.
</content>
</entry>
<entry>
<title>gsp-phys: P6c C0+C1 - engine-authored guest CE semaphore (default off)</title>
<updated>2026-10-02T11:43:05+00:00</updated>
<author>
<name>Arthur Hanson Rasmusson</name>
<email>arthur@vgpu.io</email>
</author>
<published>2026-10-02T11:43:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.vgpu.io/open-iov.git/commit/?id=fe95eadb2bc1cb9af49814528edecbc5e497d6cd'/>
<id>urn:sha1:fe95eadb2bc1cb9af49814528edecbc5e497d6cd</id>
<content type='text'>
New default-off gsp_phys_relay: for a forwarded guest CE copy whose push
ends in a one-word release, the release page is resolved at forward time,
mapped on a fresh scratch line, and the real engine writes the payload
directly into the guest-visible semaphore page; the deferred-release hold
then verifies that page and skips only that record's software apply. Any
failure (unresolvable target, refused kind, pool exhaustion, poll timeout,
data mismatch, channel teardown) falls back to applying every release in
software, so a release is never lost or duplicated.

- new exported gsp_phys_backend_guest_ce_copy_ex() + relay counters;
  gsp_phys_backend_guest_ce_copy() behavior unchanged (wrapper)
- new work_relay: counters line in gsp-phys-state
- relay limited to CE channels and one-word absolute releases; counter
  and reduction releases stay on the existing paths

Live: param-off regression matched the wave-2 baseline exactly (req=101
ok=101 verify_ok=101, copy_skipped=119, smoke matched=64/64, relay zeros).
With the parameter on: requested=68 ok=67 skipped_sw=67, verify_fail=0,
resolve_fail=0, timeouts=0, smoke 64/64, and the engine-authored guest
semaphore was observed directly (sem=0x00000003 / 0x0000007e at the guest
page). One copy in 68 released its semaphore but failed the host-side data
compare; it fell back to the software apply (fallback accounting
applied+fallback==engaged) with the smoke green - residual to triage, which
is why the parameter stays default-off. A forced-unresolvable run
(requested=103, fallback=105, no relay submissions) kept the smoke green.
Every cycle: 5 power-domain locks held, driver rebound, WPR2 down, no rail
cycles, pstore empty, same boot.
</content>
</entry>
<entry>
<title>gsp-phys: P6b waves 1.5 and 2 - deferred release and hardware-authored guest copies</title>
<updated>2026-10-02T10:55:42+00:00</updated>
<author>
<name>Arthur Hanson Rasmusson</name>
<email>arthur@vgpu.io</email>
</author>
<published>2026-10-02T10:55:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.vgpu.io/open-iov.git/commit/?id=b75e316bd42cc34397e5f66b93f4c85181ad18c8'/>
<id>urn:sha1:b75e316bd42cc34397e5f66b93f4c85181ad18c8</id>
<content type='text'>
- new default-off gsp_phys_work_defer_release: a forwarded guest push's
  releases are recorded and its GPFIFO entry is held (no consume, no
  GP_GET write, no counter publish/stall) until the work item publishes
  completion; the service thread then delivers the releases, with a
  fallback on failure/timeout (500 ms cap enforced every pump pass)/
  pause/quiesce/channel-delete
- new default-off gsp_phys_work_hw_primary: the software copy is skipped
  for forwarded ops, so the physical engine authors the data; a once-only
  software copy runs before the releases on any hardware failure or when
  the request cannot be queued
- release-apply helpers extracted; exactly-once latches; channel-delete
  and teardown handling; counters and a work_guard state line
- live: deferred-release run engaged=75 applied=75 timeouts=0 with the
  full smoke green; hardware-primary run req=100 ok=100 verify_ok=100
  fallback=0 copy_skipped=119 copy_fail=0, smoke ALL OK 64/64 (guest read
  data the engine authored), with 19 fail-closed inline software
  fallbacks under single-inflight contention; a range-unregistered run
  proved the fallback (121 skipped copies, all recovered, smoke green)
- defaults off; the software path and all existing guards unchanged
</content>
</entry>
<entry>
<title>gsp-phys: P6a - real copy engine reads/writes guest RAM pages</title>
<updated>2026-10-02T07:31:06+00:00</updated>
<author>
<name>Arthur Hanson Rasmusson</name>
<email>arthur@vgpu.io</email>
</author>
<published>2026-10-02T07:24:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.vgpu.io/open-iov.git/commit/?id=d2de7bf1d6bb7d0931085f87da6c3013cd7f1aca'/>
<id>urn:sha1:d2de7bf1d6bb7d0931085f87da6c3013cd7f1aca</id>
<content type='text'>
- file-backed guest RAM (launcher memory-backend-file share=on) and
  in-kernel GPA-&gt;HPA translation through the shared file page cache
  (read_cache_page + page_to_phys + pfn_valid), opened O_LARGEFILE;
  new default-off gsp_phys_guest_mem parameter
- debugfs gsp-phys-guest-ram (path + gpa/off/size ranges) and
  gsp-phys-guest-gpa (one pinned GPA per boot); rm-call triggers 6/7 run
  host-&gt;guest and guest-&gt;host 4 KiB CE copies; trigger 8 is a PTE
  self-test through a fresh slot
- guest page-table slots are pre-built during ladder stage 3: runtime
  PTE writes into an already-walked page-table line are not observed
  without a TLB invalidate
- guest RAM layout (q35 4.2, 4 GiB): below-4G GPA == file offset,
  above-4G offset = GPA - 0x80000000 (2 GiB PCI hole)
- tests: tools/test/gpage_test.c guest probe; docs + STATE-CURRENT
  record the live green (G2H/W2G with semaphore release, guest observed
  the write, smoke ALL OK 64/64, clean latched release)
</content>
</entry>
<entry>
<title>gsp-phys: freeze-safe release, boot-proof READY, and guest-wiring P2/P3/P5-wave1</title>
<updated>2026-10-02T06:07:52+00:00</updated>
<author>
<name>Arthur Hanson Rasmusson</name>
<email>arthur@vgpu.io</email>
</author>
<published>2026-10-02T06:07:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.vgpu.io/open-iov.git/commit/?id=c886760efda836b060fee03bfce852f16f04b5b8'/>
<id>urn:sha1:c886760efda836b060fee03bfce852f16f04b5b8</id>
<content type='text'>
Host-freeze fix bundle (validated 2/2 supervised cycles):
- power unlock now latches D0/D3cold by default (new gsp_phys_repower,
  default 0); releasing the claim can no longer power-gate the board and
  hard-freeze the host on resume
- bounded post-rebind readiness gate before dropping the locks; bounded D0
  settle/verify before the unbind
- READY means a live GSP-RM session: the async worker and the module-owned
  join only expose READY when init-done is seen and no unload was sent;
  otherwise the claim is released fail-open
- FWSEC reads DMEM0/IMEM back before STARTCPU and fails fast when the
  staging is not visible
- the claim harness leaves the board latched by default and takes
  --restore-power to opt back into the old restore

Guest-wiring:
- P2: generation-keyed fn65 static-config snapshot cache plus a default-off
  identity overlay (new gsp_phys_static_live) for name/short-name/VBIOS;
  the probe cycle runs once per backend generation at READY
- P3: default-off read-only RM_CONTROL forwarding whitelist (new
  gsp_phys_ctrl_forward) with emulated-handle translation to the adopted
  server handles and full emulation fallback
- P5 wave 1: default-off shadow execution of guest CE pushes on the ladder
  channel (new gsp_phys_work_forward) via a dedicated ordered work item;
  the ladder stage-4 submission is refactored into a shared bounded helper
  and the software release path stays authoritative

Live: module-owned boot to init-done, guest smoke ALL OK 64/64 with P2/P3
enabled, 514 shadow copies observed on the physical CE; all cycles released
cleanly with WPR2 down and no reboot.
</content>
</entry>
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