r576 diag: launch-decision + event-post payload witnesses (gsp_phys_gr_dec_log, gsp_rm_ev_log)

The GR launch-decision dump logs, for the first N draws whose fill saw
dropped pages / a partial argument set or whose decision point carries a
dstpend/copy-pending verdict: the decision verdicts, the launch's resolved
data pages (VA -> guest PA), the live deferred-write records and the pending
CE opdef entries - the operand evidence needed to explain a red draw of the
readback lottery (the wrong-but-similar page hypothesis).

The event-post witness logs every EVENT_POST_EVENT record actually sent with
its full payload (hClient/hEvent/notifyIndex/data) and send result, plus a
sentinel when post_all_events found valid events but posted none while none
were dedup-skipped. This is the evidence needed when a client parks waiting
for a completion wake-up that never arrives (the 2nd-client device-state
spin): it shows whether the post was generated, for whom, and whether the
status-queue write accepted it or dropped it (burst cap / ring full).

Both are inert by default (budget 0).

1 files changed, 9 insertions, 0 deletions

diff --git a/kernel/gsp_rm_emulation.h b/kernel/gsp_rm_emulation.h
index 45fcc64..9dc354d 100644
--- a/kernel/gsp_rm_emulation.h
+++ b/kernel/gsp_rm_emulation.h
@@ -207,6 +207,15 @@ struct gsp_rm_emu {
 	unsigned long event_burst_at;	/* m171: burst window start (time-based reset) */
 };
 
+/*
+ * r576 DIAG: per-boot witness budget for GSP event-post payloads (default 0
+ * = off). Nonzero logs every EVENT_POST_EVENT record actually sent (slot,
+ * hClient, hEvent, notifyIndex, data, send rc) and the sentinel case of a
+ * post_all_events call that found nothing postable - the evidence needed
+ * when a client parks waiting for a completion wake-up that never arrives.
+ */
+extern unsigned gsp_rm_ev_log_max;
+
 int  gsp_rm_emu_init(struct nv_vgpu_device *vgpu, struct gsp_emu_context *ctx);
 void gsp_rm_emu_fini(struct gsp_emu_context *ctx);
 int  gsp_rm_post_channel_event(struct nv_vgpu_device *vgpu, u32 h_src);