guest-diag: resolve and stream the PMA scrubber buffer words (third-client scrub freeze)

guest_pin_stream: find the scrubber channel buffer among the nvidia vmap
areas (size in the CeUtils channel set, 906F ring shape at +0x64000 when
non-empty), walk its pages with kcore and emit '#scrub <fin_pa>,<hsem_pa>'
(the finish payload at +0x6c004 and the host semaphore at +0x6c000).

pin_gr_stream: handle '#scrub' lines and register the PAs through the
sema_scrubbuf_add module parameter, so the kernel's svc_scrub_pass can
author the guest's scrub progress.

1 files changed, 23 insertions, 0 deletions

diff --git a/tools/guest-diag/pin_gr_stream.py b/tools/guest-diag/pin_gr_stream.py
index b864ab5..2a5d768 100644
--- a/tools/guest-diag/pin_gr_stream.py
+++ b/tools/guest-diag/pin_gr_stream.py
@@ -101,6 +101,22 @@ def inject(va, pa, ln):
     return False
 
 
+def scrub_register(fin_pa, hsem_pa):
+    """Register the PMA scrubber buffer words (guest-resolved PAs) with the
+    service so it can author the scrub progress (third-client scrub freeze)."""
+    cmd = ("printf '0x%x,0x%x' > %s/sema_scrubbuf_add"
+           % (fin_pa, hsem_pa, PARAM))
+    for _ in range(60):
+        r = subprocess.run(["sudo", "-n", "sh", "-c", cmd],
+                           capture_output=True, text=True)
+        if r.returncode == 0:
+            log("scrub registered fin=0x%x hsem=0x%x" % (fin_pa, hsem_pa))
+            return True
+        time.sleep(0.05)
+    log("scrub register FAILED fin=0x%x hsem=0x%x" % (fin_pa, hsem_pa))
+    return False
+
+
 def main():
     if not install_and_start():
         log("WARN: could not start guest scanner (will retry via vsock wait)")
@@ -158,6 +174,13 @@ def main():
                     log(text)
                     _mirror(text)
                     continue
+                if text.startswith("#scrub"):
+                    m = re.search(r"0x([0-9a-fA-F]+),0x([0-9a-fA-F]+)", text)
+                    _mirror(text)
+                    if m:
+                        scrub_register(int(m.group(1), 16),
+                                       int(m.group(2), 16))
+                    continue
                 m = re.match(r"^(0x[0-9a-f]+),(0x[0-9a-f]+)(?:,(\d+))?$", text)
                 if m:
                     runs.append((int(m.group(1), 16), int(m.group(2), 16),