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-rw-r--r--tools/guest-diag/wall2/README-session77.md48
-rw-r--r--tools/guest-diag/wall2/fence_assist.py112
-rw-r--r--tools/guest-diag/wall2/find_push.py59
3 files changed, 219 insertions, 0 deletions
diff --git a/tools/guest-diag/wall2/README-session77.md b/tools/guest-diag/wall2/README-session77.md
index 1834c29..d830bef 100644
--- a/tools/guest-diag/wall2/README-session77.md
+++ b/tools/guest-diag/wall2/README-session77.md
@@ -1145,3 +1145,51 @@ complete the fence when it consumes the submit's GPFIFO entries); (2)
then the first VKFRAME seq/DONE + PPM; (3) fold the COMPR flip into a
host-side answer (see D); (4) the mission series (Xorg/GZDOOM, KVMFR,
CUDA 15/15 + soak, test series, video, Windows).
+
+**40. Session 115: THE FENCE WALL DECOMPOSED - THE CLIENT VAS PAGE DIRECTORY IS UNDISCOVERABLE AND THE PUSHES ARE NONCONTIGUOUS; RING PAGES ARE CONTENT-LOCATABLE AND INJECTABLE, BUT THE RING PAIR ALONE DOES NOT UNLOCK THE PUSH DECODE.**
+(1) The fence timeout is upstream of everything else: the sema service cannot
+decode the submit's GR pushes (`sema-entry: unread ... va=0x4ca0000
+len=1432` -> `skipping stale entry ... after 185-194 failed rescues`;
+`work_gr submitted=0` - no GR forward ever starts). (2) The pump's push
+reads resolve ONLY through the client VAS page directory (or pins). The
+service has NO pdb for this client: `walk_probe` of the ring and push VAs
+prints `discovered pdb=0x0 found=0` and no registered VASes; the r496f
+vidmem pdb discovery never ran (it is only called from the RAM ring-scan
+latch), and the r496j COPY_SERVER_PDES candidate (0x109b9c000) is garbage
+(its content is not a page table). (3) THE RAM RING SCAN MISSES BY
+CONSTRUCTION for this client: it sweeps [0, 6 GB) in 12 slices and gives
+up (`found no candidate in 12 slice(s)`), but the sweep runs BEFORE the
+client's pushes exist and never re-runs - while the ring page content is
+provably in RAM (content-located below). (4) CONTENT LOCATION WORKS: the
+GR ring page (ring VA 0x4cc0000, first entries {va=0x4ca0000 len=1432,
+va=0x4ca0598 len=4}) was found in the guest RAM file by its first two GPFIFO
+entries (at GPA 0x12C600000 then 0x12898c000 on later runs - per-run
+allocations), and `sema_map_add` injection of the TRUE ring pair is
+accepted (`INJECT va=0x4d20000 pa=0x13619d000 : ok`). BUT the pushes do not
+become readable from the ring pair alone: the pushbuffer is NONCONTIGUOUS
+(the window guess `ring_pa - 0x20000` reads zeros for both the GR and the
+CE channels), the pushes are not CPU-mapped in the client process (the
+ring GPA is absent from /proc/PID/pagemap of every rw-s nvidia mapping),
+and a bottom-up search for the level-3 table (a 4 KB page whose index-2
+big/small entry maps into the ring's 2 MB window) found ZERO candidates in
+RAM - the page tables are almost certainly in VIDMEM (r496f's note) or use
+a shape the walker does not model. (5) The service's OWN successful read of
+one CE init push (`sema-push: h=0xbeec0104 va=0x4d00000 ... rel=0x4b19b10
+pay=1 have_rel=1`, `ops_runs=0`) did NOT apply its release either -
+whatever resolved that one read is not reproducible for the GR pushes.
+NEW TOOLS: `fence_assist.py` (host: watches a `dmesg -w` capture for the
+pump's entry decodes, content-locates the ring pages by their first two
+entries in the RAM file, injects the pairs via sema_map_add - proven to
+find and inject, but the ring pair alone is insufficient) and
+`find_push.py` (guest: tests whether the client CPU-maps the ring GPA).
+NEXT (ranked, concrete): (1) find the client VAS page directory: extract the
+pdb from the GUEST kernel's RM objects (kcore walk of the VAS/GPU object
+for this channel - the GPFIFO ring page content anchors the search), then
+register it via the service's VAS table (a new sysfs/debugfs entry point
+or the existing candidate path) - this is the "PDB injection" the mission
+names; (2) or scan VIDMEM for the pdb with the ring pair as the verifier
+(extend `svc_xvas_pdb_discover`'s trigger: call it from the ring-injection
+path, not only from the RAM scan latch); (3) make the RAM ring scan re-arm
+per channel with the pushes present (its 12-slice give-up is the reason
+the auto-discovery never latches on this client); (4) then the submit
+decodes, the release lands and `vkWaitForFences` returns -> VKFRAME.
diff --git a/tools/guest-diag/wall2/fence_assist.py b/tools/guest-diag/wall2/fence_assist.py
new file mode 100644
index 0000000..4ea0b0c
--- /dev/null
+++ b/tools/guest-diag/wall2/fence_assist.py
@@ -0,0 +1,112 @@
+#!/usr/bin/env python3
+# fence_assist.py - content-locate the client's ring pages in guest RAM from the
+# service's own GPFIFO entry decodes (dmesg) and inject the TRUE VA->PA pairs
+# via sema_map_add, so the pump's push reads (and its pushbuffer pairing) have
+# a correct anchor.
+import mmap, re, struct, subprocess, sys, threading, time
+
+F = "/dev/shm/vgpu-guest-ram"
+PARAM = "/sys/module/vgsp/parameters/sema_map_add"
+
+def gpa_of(fo):
+ return fo if fo < 0x80000000 else fo - 0x80000000 + 0x100000000
+
+def inject(va, pa, ln=0x1000, flag=1):
+ cmd = "echo 0x%x,0x%x,0x%x,%d > %s" % (va & ~0xfff, pa & ~0xfff, ln, flag, PARAM)
+ r = subprocess.run(["sudo", "sh", "-c", cmd], capture_output=True)
+ print("INJECT va=0x%x pa=0x%x : %s" % (va & ~0xfff, pa & ~0xfff,
+ "ok" if r.returncode == 0 else "FAIL"), flush=True)
+
+def search(mm, pats, results):
+ CH = 8 << 20
+ size = len(mm)
+ off = 0
+ while off < size:
+ d = mm[off:off+CH]
+ for (name, pat) in pats.items():
+ if name in results:
+ continue
+ i = d.find(pat)
+ if i >= 0:
+ results[name] = gpa_of(off + i)
+ off += CH - 32
+
+def main():
+ dur = float(sys.argv[1]) if len(sys.argv) > 1 else 120
+ f = open(F, "rb")
+ mm = mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ)
+ end = time.time() + dur
+ pats = {} # name -> pattern bytes
+ ring_va = {} # name -> ring VA
+ seen = set() # raw entry lines processed
+ done = set() # injected names
+ print("# fence_assist start (%.0fs)" % dur, flush=True)
+ while time.time() < end:
+ try:
+ with open("/tmp/opencode/dmsg_w.txt", "r", errors="ignore") as df:
+ tail = df.read().splitlines()[-6000:]
+ out = "\n".join(tail)
+ except OSError:
+ out = ""
+ tail = []
+ tail = [ln for ln in tail if "sema-chan:" in ln or "sema-push" in ln]
+ cur = {}
+ for ln in tail:
+ m = re.search(r"sema-chan: entry\[(\d+)\] h=0x([0-9a-f]+) eng=\d+ raw=([0-9a-f]+) va=0x([0-9a-f]+)", ln)
+ if m:
+ idx, h, raw, va = int(m.group(1)), m.group(2), int(m.group(3), 16), int(m.group(4), 16)
+ cur.setdefault(h, {})[idx] = raw
+ if idx == 0:
+ ring_va[h] = va # entry[0] va is the push VA (ring_va - 0x20000)
+ for h, ents in cur.items():
+ key = (h, tuple(sorted(ents.items())))
+ if key in seen or len(ents) < 2:
+ continue
+ seen.add(key)
+ name = h
+ pat = b"".join(struct.pack("<Q", ents[i]) for i in sorted(ents)[:2])
+ pats[name] = pat
+ print("# channel h=0x%s entries=%s pattern ready" % (h, sorted(ents)), flush=True)
+ if pats:
+ results = {}
+ threads = []
+ # split the map among 4 threads
+ LO = 0x100000000; HI = 0x180000000
+ size = len(mm)
+ step = size // 4
+ class Sl(shim := object):
+ def __init__(self, a, b):
+ self.a, self.b = a, b
+ def worker(a, b):
+ CH = 8 << 20
+ off = a
+ while off < b:
+ if off < 0x80000000 and b <= 0x80000000: pass
+ d = mm[off:off+CH]
+ for (nm, p) in list(pats.items()):
+ if nm in results: continue
+ i = d.find(p)
+ if i >= 0:
+ results[nm] = gpa_of(off + i)
+ off += CH - 32
+ for k in range(4):
+ a = 0x80000000 + k * (0x80000000 // 4)
+ b = 0x80000000 + (k + 1) * (0x80000000 // 4)
+ t = threading.Thread(target=worker, args=(a, b))
+ t.start(); threads.append(t)
+ for t in threads: t.join()
+ for nm, gpa in results.items():
+ if nm in done: continue
+ done.add(nm)
+ # ring page content starts with entry[0]; the ring VA is the
+ # channel's gpfifo VA = we reconstruct: entry0 va is the push,
+ # ring = first "gpfifo=0x..." dmesg line for this h
+ m = re.search(r"sema-chan: h=0x%s eng=\d+ cid=\d+ gpfifo=0x([0-9a-f]+)" % nm, out)
+ rva = int(m.group(1), 16) if m else None
+ if rva:
+ print("RING FOUND h=0x%s gpfifo_va=0x%x -> gpa=0x%x" % (nm, rva, gpa), flush=True)
+ inject(rva, gpa, 0x1000)
+ time.sleep(0.6)
+ print("# fence_assist done, injected %d" % len(done), flush=True)
+
+main()
diff --git a/tools/guest-diag/wall2/find_push.py b/tools/guest-diag/wall2/find_push.py
new file mode 100644
index 0000000..4bf8ccc
--- /dev/null
+++ b/tools/guest-diag/wall2/find_push.py
@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+# find_push.py - locate the client's CPU mapping that owns the GR ring page
+# (GPA 0x12C600000 as content-located on the host) and print the CPU VA<->
+# GPU VA correspondence for the low GPU VAs (0x4ca0000 etc).
+import os, struct, sys, subprocess, mmap, time
+
+RING_GPA = 0x12C600000
+PUSH_GVA = 0x4ca0000
+RING_GVA = 0x4cc0000
+
+def pids():
+ out = subprocess.run(["pgrep", "-x", "vk_frame"], capture_output=True).stdout
+ return [int(x) for x in out.split()]
+
+def read_pagemap(pid, va):
+ try:
+ with open("/proc/%d/pagemap" % pid, "rb") as f:
+ f.seek((va // 4096) * 8)
+ d = f.read(8)
+ if len(d) < 8:
+ return None
+ e = int.from_bytes(d, "little")
+ if not (e >> 63) & 1:
+ return None
+ return (e & ((1 << 55) - 1)) << 12
+ except OSError:
+ return None
+
+def main():
+ for pid in pids():
+ print("pid=%d" % pid)
+ try:
+ maps = open("/proc/%d/maps" % pid).read().splitlines()
+ except OSError:
+ continue
+ for line in maps:
+ p = line.split()
+ if len(p) < 6 or "nvidia" not in p[-1]:
+ continue
+ lo, hi = [int(x, 16) for x in p[0].split("-")]
+ if hi - lo > 0x1000000:
+ continue
+ # scan pages; look for RING_GPA
+ for va in range(lo, hi, 0x10000):
+ for off in range(0, 0x10000, 0x1000):
+ pa = read_pagemap(pid, va + off)
+ if pa == RING_GPA:
+ print("FOUND ring page: cpu_va=0x%x (map 0x%x-0x%x %s)" % (va+off, lo, hi, p[-1]))
+ delta_cpu = (va + off) - RING_GVA
+ push_cpu = PUSH_GVA + delta_cpu
+ print(" delta_cpu = 0x%x" % delta_cpu)
+ for gva in (PUSH_GVA, PUSH_GVA+0x1000, 0x4ca059c, 0x4ca0980, 0x4ca5870, 0x4903000):
+ cva = gva + delta_cpu
+ pa2 = read_pagemap(pid, cva & ~0xfff)
+ print(" gva=0x%x -> cpu=0x%x -> pa=%s" % (gva, cva, hex(pa2) if pa2 else None))
+ return
+ print(" ring GPA 0x%x not found in this pid's mappings" % RING_GPA)
+
+main()