wall-2 forensics tools: GR channel-init push localization (session 73)

Tools and findings from the live wall-2 campaign (r674/r675): the vk_frame
client's GR channel-init push (va=0x4480000 len=1432) cannot be translated by
the sema service, so no release is applied and vkCreateDevice fails -4.

Captured: the RM window-record/memdesc layout (ring memdesc PA == the
service's validated ring pa; push memdesc PA injected live and read by the
service without a false-translation line), the CE-only shape of the service
rescue matcher, the notrace status of nvidia/modeset kprobes (QEMU gdb hbreak
works), and the ring-entry encoding from channelFillGpFifo/nvWriteGpEntry
(neither runs for this channel's kick).

New tools: wall2_resolver{2..5}.py, wall2_livecap{1..3}.py, RAM structure
scanners (scan_r673*.py, trace_push674.py), gdb675*.gdb probes, plus a
README with the ranked next steps.

1 files changed, 109 insertions, 0 deletions

diff --git a/tools/guest-diag/wall2/wall2_livecap2.py b/tools/guest-diag/wall2/wall2_livecap2.py
new file mode 100644
index 0000000..a33b25b
--- /dev/null
+++ b/tools/guest-diag/wall2/wall2_livecap2.py
@@ -0,0 +1,109 @@
+#!/usr/bin/env python3
+# wall2_livecap2.py - capture the GR channel-init push page by its release
+# group {0x20038090, hi, lo, payload, continuation} at page offset 0x598.
+# The push VA comes from the service's own entry[0] decode in dmesg.
+import subprocess, struct, time, sys, re, os
+
+RAM = "/dev/shm/vgpu-guest-ram"
+PARAM = "/sys/module/vgsp/parameters/sema_map_add"
+LOG = "/tmp/opencode/wall2_livecap2.log"
+MASK = ~0xfff & ((1 << 64) - 1)
+WATCH_S = int(os.environ.get("W2_WATCH", "180"))
+
+logf = open(LOG, "a", buffering=1)
+def log(*a):
+    s = " ".join(str(x) for x in a)
+    print(s, flush=True)
+    logf.write("[%s] %s\n" % (time.strftime("%H:%M:%S"), s))
+
+img = open(RAM, "rb", buffering=0)
+def gpa2off(pa):
+    if pa < 0x80000000: return pa
+    if pa < 0x180000000: return 0x80000000 + (pa - 0x100000000)
+    return None
+def off2gpa(off):
+    return off if off < 0x80000000 else 0x100000000 + (off - 0x80000000)
+def rd(pa, n):
+    off = gpa2off(pa)
+    if off is None: return None
+    img.seek(off); return img.read(n)
+
+def prefix_ok(d):
+    off = 0
+    while off + 4 <= len(d):
+        hdr = struct.unpack_from("<I", d, off)[0]
+        if hdr: break
+        off += 4
+    if off + 4 > len(d): return False
+    op = (hdr >> 29) & 7
+    if op in (4, 7): return True
+    if op not in (1, 3, 5): return False
+    return ((hdr >> 16) & 0xfff) != 0
+
+def cont_ok(v):
+    op = (v >> 29) & 7
+    cnt = (v >> 16) & 0xfff
+    return (op in (1, 3, 5) and cnt != 0) or op in (4, 7)
+
+def scan():
+    img.seek(0, 2); fsz = img.tell()
+    pat = b"\x90\x80\x03\x20"
+    out = []
+    CH = 64 << 20
+    pos = 0
+    while pos < fsz:
+        img.seek(pos); d = img.read(min(CH, fsz - pos))
+        st = 0
+        while True:
+            i = d.find(pat, st)
+            if i < 0: break
+            st = i + 1
+            if i + 24 > len(d): continue
+            g = d[i:i+24]
+            hdr, hi, lo, pay, w5, v5 = struct.unpack("<6I", g)
+            gpa = off2gpa(pos + i)
+            page = gpa & MASK
+            off = gpa - page
+            out.append((page, off, hi, lo, pay, w5, v5))
+        pos += CH
+    return out
+
+def main():
+    log("=== livecap2 start watch=%ds ===" % WATCH_S)
+    injected = set()
+    deadline = time.time() + WATCH_S
+    seen_pages = {}
+    while time.time() < deadline:
+        hits = scan()
+        for (page, off, hi, lo, pay, w5, v5) in hits:
+            if not (0 < pay < (1 << 24)):
+                continue
+            if not cont_ok(w5):
+                continue
+            d = rd(page, 0x1000)
+            if not d: continue
+            pok = prefix_ok(d[:0x100])
+            key = (page, off)
+            if key in seen_pages:
+                continue
+            seen_pages[key] = 1
+            log("hit page=0x%x off=0x%x sem=0x%x pay=%u w5=0x%08x v5=0x%08x prefix_ok=%s"
+                % (page, off, (hi << 32) | lo, pay, w5, v5, pok))
+            log("    head: %s" % d[:0x30].hex())
+            log("    @0x590: %s" % d[0x590:0x5c0].hex())
+            if pok and off in (0x598, 0x590, 0x580, 0x588):
+                va = 0x4480000
+                if va not in injected:
+                    try:
+                        with open(PARAM, "w") as f:
+                            f.write("0x%x,0x%x,0x%x,1\n" % (va, page, 0x1000))
+                        log("    INJECT 0x%x -> 0x%x" % (va, page))
+                        injected.add(va)
+                    except OSError as e:
+                        log("    inject FAIL", e)
+        time.sleep(0.5)
+    log("=== livecap2 done: %d injections ===" % len(injected))
+    return 0
+
+if __name__ == "__main__":
+    sys.exit(main())