#!/bin/bash
# pin_sem_fast.sh - low-latency tracker-sem pinner (2 s poll vs 15 s).
#
# Pins the client tracker-sem page (0x20400f000, covers 0x20400fec0..ff70)
# for the live cdt pid the moment the guest pagemap shows it present, once
# per pid. The window matters: in the one boot where UVM's page-table write
# pushes were submitted, the pin had landed ~40 s before the client's
# internal deadline; later pins (60 s+) lose the race and the client dies
# without ever submitting the writes.
#
# Usage: tools/guest-diag/pin_sem_fast.sh [iterations]   (default 200, ~7 min)
set -u
cd "$(dirname "$(readlink -f "$0")")/../.."
EXEC() { timeout 20 ./scripts/vgpu_vm.py exec --timeout 15 "$1" 2>/dev/null; }

B64=$(base64 -w0 tools/guest-diag/guest_pmap_all.py)
EXEC "echo '$B64' | base64 -d > /tmp/pmapall.py" >/dev/null

N=${1:-200}
pinned_pid=""
for ((i = 1; i <= N; i++)); do
    pid=$(EXEC 'pgrep -x cdt | head -1' | tail -1)
    if [ -n "$pid" ] && [ "$pid" != "$pinned_pid" ]; then
        line=$(EXEC "sudo python3 /tmp/pmapall.py $pid 0x20400f000 1" |
            grep -aE "^0x20400f000,0x[0-9a-f]+$" | head -1)
        if [ -n "$line" ]; then
            echo "$line,0x1000,1" | sudo tee /sys/module/open_iov_vfio/parameters/sema_map_add >/dev/null
            pinned_pid="$pid"
            echo "[$((i * 2))s] pinned $line (pid $pid)"
        fi
    fi
    sleep 2
done