From 2954ee131bed4f0fa6aacae46bb6f987799135e2 Mon Sep 17 00:00:00 2001
From: Arthur Hanson Rasmusson <arthur@vgpu.io>
Date: Sun, 25 Oct 2026 10:38:34 -0400
Subject: wall2: session 88 - push page-5 injection fix (proven +30/sweep),
 host_resolve tool, RING GAP diagnosis (gpfifo done=0), gdb-SIGKILL RM-lock
 wedge lesson

---
 tools/guest-diag/wall2/gr_walk2.py | 89 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)
 create mode 100644 tools/guest-diag/wall2/gr_walk2.py

(limited to 'tools/guest-diag/wall2/gr_walk2.py')

diff --git a/tools/guest-diag/wall2/gr_walk2.py b/tools/guest-diag/wall2/gr_walk2.py
new file mode 100644
index 0000000..7a50bc8
--- /dev/null
+++ b/tools/guest-diag/wall2/gr_walk2.py
@@ -0,0 +1,89 @@
+#!/usr/bin/env python3
+# gr_walk2.py - deeper walk: from the window memdesc records, follow the
+# kernel pointers 2-3 levels and search for page-array records
+# {vmap_cpu, flags, PA, 0x1000} (2+ consecutive) to recover the page lists.
+import sys, struct
+sys.path.insert(0, "/tmp")
+import guest_pin_stream as gps
+
+PAT_SIZE = struct.pack("<Q", 0x20000)
+PAT_FLAGS = struct.pack("<Q", 0x03008000)
+
+def is_pa(v):
+    return 0x100000000 <= v < 0x180000000
+
+def page_array_at(kc, va, n=0x400):
+    """Return [(off, [PA,...])] for runs of {ptr,flags,PA,0x1000} records."""
+    d = kc.read(va, n)
+    if not d:
+        return []
+    out = []
+    i = 0
+    while i + 32 <= len(d):
+        p, fl, pa, z = struct.unpack_from("<4Q", d, i)
+        if z == 0x1000 and is_pa(pa) and gps.is_kern_ptr(p):
+            run = [pa]
+            j = i + 32
+            while j + 32 <= len(d):
+                p2, fl2, pa2, z2 = struct.unpack_from("<4Q", d, j)
+                if z2 == 0x1000 and is_pa(pa2):
+                    run.append(pa2)
+                    j += 32
+                else:
+                    break
+            if len(run) >= 2:
+                out.append((i, run))
+            i = j
+        else:
+            i += 8
+    return out
+
+def main():
+    kc = gps.Kcore()
+    if not kc.load():
+        print("# kcore load failed"); return 1
+    pov = kc.page_offset_base
+    # find memdesc records (fast direct-map scan)
+    found = []
+    CH = 1 << 20
+    pa = 0x100000000
+    while pa < 0x180000000 and len(found) < 12:
+        d = kc.read(pov + pa, CH)
+        if d:
+            st = 0
+            while True:
+                i = d.find(PAT_SIZE, st)
+                if i < 0:
+                    break
+                st = i + 1
+                if i + 16 <= len(d) and d[i+8:i+16] == PAT_FLAGS:
+                    found.append((pa + i, d[i:i+0x40]))
+        pa += CH
+    print("# memdesc records: %d" % len(found))
+    for (gpa, rec) in found:
+        size, flags = struct.unpack_from("<QQ", rec, 0)
+        wpa = struct.unpack_from("<Q", rec, 0x10)[0]
+        print("rec@0x%x size=0x%x pa=0x%x" % (gpa, size, wpa))
+        kptrs = [struct.unpack_from("<Q", rec, o)[0] for o in range(0x18, 0x40, 8)]
+        for kp in kptrs:
+            if not gps.is_kern_ptr(kp):
+                continue
+            # level 1: read the target, look for page arrays directly
+            for arr in page_array_at(kc, kp):
+                print("   L1 kptr 0x%x: page-array run at +0x%x: %s" %
+                      (kp, arr[0], ["0x%x" % x for x in arr[1][:12]]))
+            # level 2: follow pointers in the target
+            d = kc.read(kp, 0x100)
+            if not d:
+                continue
+            for o in range(0, 0x100, 8):
+                p2 = struct.unpack_from("<Q", d, o)[0]
+                if not gps.is_kern_ptr(p2):
+                    continue
+                for arr in page_array_at(kc, p2):
+                    print("   L2 0x%x -> 0x%x: page-array at +0x%x: %s" %
+                          (kp, p2, arr[0], ["0x%x" % x for x in arr[1][:12]]))
+    return 0
+
+if __name__ == "__main__":
+    sys.exit(main())
-- 
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