tools: durable guest counter enumeration/injection and VA reader

The counter enumeration/injection workflow lived in the guest's /tmp and was
lost on every restart. Make it durable under tools/guest-diag:

- sem_counters.py: translate a process's per-channel u32 completion counters
  (16-byte stride in the /dev/nvidiactl counter page) to guest PAs through
  /proc/<pid>/pagemap; --pairs emits handle,va,pa triples.
- sem_slots.py: read/write the counter slots via /proc/<pid>/mem (fallback
  for the host counter publish).
- read_va.py: hex dump a process VA (UVM sysmem GPU VAs are usually valid
  CPU VAs in the owning process); --u32 for method streams.
- inject_counters.sh: host-side one-shot: push the tool, take the GR handles
  from the live chan_dump, enumerate, then register each counter with
  sema_counter and pin its VA with sema_map_add.
- push_guest_tools.sh: push the new tools after every VM start.
- launch_qemu_direct.sh: parameterized mdev UUID/paths instead of a stale
  hardcoded one; committed so it survives checkouts.

1 files changed, 61 insertions, 0 deletions

diff --git a/tools/guest-diag/read_va.py b/tools/guest-diag/read_va.py
new file mode 100755
index 0000000..fca3994
--- /dev/null
+++ b/tools/guest-diag/read_va.py
@@ -0,0 +1,61 @@
+#!/usr/bin/env python3
+# read_va.py - dump a guest process's memory at a VA (GPU VAs of UVM sysmem
+# objects are usually also valid CPU VAs in the owning process).
+#
+# Usage:
+#   sudo python3 read_va.py <pid> <va-hex> [len] [--u32]
+#
+# --u32 prints one little-endian u32 per line (method-stream friendly).
+import os
+import sys
+
+
+def main():
+    if len(sys.argv) < 3:
+        print(__doc__)
+        return 1
+    pid = int(sys.argv[1])
+    va = int(sys.argv[2], 16)
+    ln = 256
+    as_u32 = False
+    for a in sys.argv[3:]:
+        if a == '--u32':
+            as_u32 = True
+        else:
+            ln = int(a, 0)
+
+    found = False
+    with open('/proc/%d/maps' % pid) as f:
+        for line in f:
+            rng = line.split()[0]
+            a, b = rng.split('-')
+            if int(a, 16) <= va < int(b, 16):
+                print('MAP: %s' % line.strip())
+                found = True
+                break
+    if not found:
+        print('VA 0x%x not in maps' % va)
+
+    mem = os.open('/proc/%d/mem' % pid, os.O_RDONLY)
+    try:
+        data = os.pread(mem, ln, va)
+    except OSError as e:
+        print('read error: %s' % e)
+        return 1
+    finally:
+        os.close(mem)
+
+    if as_u32:
+        for i in range(0, len(data) - 3, 4):
+            print('+0x%03x: 0x%08x' %
+                  (i, int.from_bytes(data[i:i + 4], 'little')))
+    else:
+        for i in range(0, len(data), 16):
+            chunk = data[i:i + 16]
+            hexs = ' '.join('%02x' % b for b in chunk)
+            print('+0x%03x: %s' % (i, hexs))
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main())