gsp-phys: freeze-safe release, boot-proof READY, and guest-wiring P2/P3/P5-wave1

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.

1 files changed, 20 insertions, 4 deletions

diff --git a/kernel/main.c b/kernel/main.c
index f47ef69..3784a70 100644
--- a/kernel/main.c
+++ b/kernel/main.c
@@ -1452,9 +1452,23 @@ static int __init nv_vgpu_init(void)
 
 	if (gsp_phys_gpu_param && !gsp_phys_mdev_owned_enabled()) {
 		ret = gsp_phys_gpu_claim();
-		if (ret)
+		if (ret) {
 			pr_warn("gsp-resman-vfio: physical GPU claim failed: %d\n",
 				ret);
+		} else {
+			/*
+			 * G0.4 (P2 prep): expose the load-time module-owned
+			 * claim as a READY backend session. The join path only
+			 * marks the state and schedules the static-config
+			 * snapshot probe (a work item); failure is non-fatal,
+			 * module load keeps the emulation path. The claim
+			 * itself is still released at rmmod.
+			 */
+			ret = gsp_phys_backend_start();
+			if (ret)
+				pr_warn("gsp-resman-vfio: physical backend start failed: %d\n",
+					ret);
+		}
 	} else if (gsp_phys_gpu_param) {
 		pr_info("gsp-resman-vfio: gsp_phys_mdev_owned=1: physical GPU claim+boot deferred to the first mdev create\n");
 	} else if (gsp_phys_mdev_owned_enabled()) {
@@ -1518,10 +1532,12 @@ static void __exit nv_vgpu_exit(void)
 		gsp_phys_backend_begin_stop();
 	} else {
 		/*
-		 * Module-owned claim (gsp_phys_gpu=1, mdev_owned=0): keep
-		 * today's position relative to the debugfs teardown and the
-		 * emulation threads; module-owned sessions never forward live.
+		 * Module-owned claim (gsp_phys_gpu=1, mdev_owned=0): flush the
+		 * static-config probe work item (begin_stop's only effect for a
+		 * module-owned session), then keep today's release position
+		 * relative to the debugfs teardown and the emulation threads.
 		 */
+		gsp_phys_backend_begin_stop();
 		gsp_phys_gpu_release();
 	}