diff --git a/tests/hwsim/vm/parallel-vm.py b/tests/hwsim/vm/parallel-vm.py
index 42083f761..6436c341c 100755
--- a/tests/hwsim/vm/parallel-vm.py
+++ b/tests/hwsim/vm/parallel-vm.py
@@ -129,7 +129,8 @@ def main():
     vm = {}
     for i in range(0, num_servers):
         print("\rStarting virtual machine {}/{}".format(i + 1, num_servers)),
-        cmd = ['./vm-run.sh', '--ext', 'srv.%d' % (i + 1),
+        cmd = ['./vm-run.sh', '--timestamp', str(timestamp),
+               '--ext', 'srv.%d' % (i + 1),
                '--split', '%d/%d' % (i + 1, num_servers)] + sys.argv[2:]
         vm[i] = {}
         vm[i]['proc'] = subprocess.Popen(cmd,
diff --git a/tests/hwsim/vm/parallel-vm.sh b/tests/hwsim/vm/parallel-vm.sh
index 9074b82e5..b2fd0786f 100755
--- a/tests/hwsim/vm/parallel-vm.sh
+++ b/tests/hwsim/vm/parallel-vm.sh
@@ -15,7 +15,7 @@ DATE=$(date +%s)
 
 for i in `seq 1 $NUM`; do
     printf "\rStarting virtual machine $i/$NUM"
-    ./vm-run.sh --ext srv.$i --split $i/$NUM $* >> $LOGS/parallel-$DATE.srv.$i 2>&1 &
+    ./vm-run.sh --timestamp $DATE --ext srv.$i --split $i/$NUM $* >> $LOGS/parallel-$DATE.srv.$i 2>&1 &
 done
 echo
 
diff --git a/tests/hwsim/vm/vm-run.sh b/tests/hwsim/vm/vm-run.sh
index 762651695..478690a9c 100755
--- a/tests/hwsim/vm/vm-run.sh
+++ b/tests/hwsim/vm/vm-run.sh
@@ -43,13 +43,18 @@ fi
 CMD=$TESTDIR/vm/inside.sh
 
 unset RUN_TEST_ARGS
-DATE=$(date +%s)
+TIMESTAMP=$(date +%s)
+DATE=$TIMESTAMP
 CODECOV=no
 TIMEWARP=0
 while [ "$1" != "" ]; do
 	case $1 in
+		--timestamp ) shift
+			TIMESTAMP=$1
+			shift
+			;;
 		--ext ) shift
-			DATE=$(date +%s).$1
+			DATE=$TIMESTAMP.$1
 			shift
 			;;
 		--codecov ) shift