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, 11 insertions, 0 deletions

diff --git a/kernel/gsp_sema_service.h b/kernel/gsp_sema_service.h
index ee5c48a..31512ef 100644
--- a/kernel/gsp_sema_service.h
+++ b/kernel/gsp_sema_service.h
@@ -292,6 +292,17 @@ extern unsigned gsp_phys_gr_hold_max_ms;
  * hold and its absolute bound apply.
  */
 extern unsigned gsp_phys_gr_fill_hold;
+
+/*
+ * r576 DIAG: per-boot witness budget for the GR launch-decision dump
+ * (default 0 = off). Nonzero logs, for the first N launches whose fill saw
+ * dropped pages / a partial argument set or whose decision point had 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 evidence needed to explain a red draw
+ * of the readback lottery.
+ */
+extern unsigned gsp_phys_gr_dec_log_max;
 extern unsigned gsp_sema_walk_trace;
 
 /*