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, 45 insertions, 0 deletions

diff --git a/tools/guest-diag/wall2/scan_r673c.py b/tools/guest-diag/wall2/scan_r673c.py
new file mode 100644
index 0000000..db69b5d
--- /dev/null
+++ b/tools/guest-diag/wall2/scan_r673c.py
@@ -0,0 +1,45 @@
+#!/usr/bin/env python3
+# r673: find the push page. Patterns: ring entry raw qwords, the sem VA, and
+# method-stream signatures. Dump contexts.
+import numpy as np, struct, os, time
+
+RAM="/dev/shm/vgpu-guest-ram"
+img=open(RAM,"rb"); fsz=os.path.getsize(RAM)
+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 or off+n>fsz: return None
+    img.seek(off); return img.read(n)
+
+pats=[
+ ("entry0raw", 0x0005980004500000),
+ ("entry1raw", 0x0000040004500598),
+ ("entry2raw", 0x0003d0000450059c),
+ ("sem_va",    0x4500598),
+ ("sem_va2",   0x450059c),
+ ("m20038090", 0x20038090),
+ ("push_va",   0x4500000),
+]
+CH=64<<20
+for name,pat in pats:
+    hits=[]
+    t0=time.time()
+    for pos in range(0,fsz,CH):
+        img.seek(pos); d=img.read(min(CH,fsz-pos))
+        n=len(d)//8
+        a=np.frombuffer(d[:n*8],dtype=np.uint64)
+        idx=np.nonzero(a==np.uint64(pat))[0]
+        for i in idx: hits.append(pos+int(i)*8)
+    print("== %s pat=0x%x hits=%d (%.1fs)" % (name,pat,len(hits),time.time()-t0))
+    for off in hits[:12]:
+        gpa=off2gpa(off); page=gpa&~0xfff
+        d=rd(page,0x1000)
+        ro=gpa-page
+        s=max(0,ro-24); e=min(0x1000,ro+40)
+        print("   gpa=0x%x page=0x%x off=0x%x ctx=%s" % (gpa,page,ro,d[s:e].hex() if d else "?"))
+    if len(hits)>12: print("   ... %d more" % (len(hits)-12))