diff --git a/tests/qemu-iotests/testrunner.py b/tests/qemu-iotests/testrunner.py
index 81519ed6e2..7b322272e9 100644
--- a/tests/qemu-iotests/testrunner.py
+++ b/tests/qemu-iotests/testrunner.py
@@ -228,13 +228,11 @@ class TestRunner(ContextManager['TestRunner']):
 
         return f'{test}.out'
 
-    def do_run_test(self, test: str, mp: bool) -> TestResult:
+    def do_run_test(self, test: str) -> TestResult:
         """
         Run one test
 
         :param test: test file path
-        :param mp: if true, we are in a multiprocessing environment, use
-                   personal subdirectories for test run
 
         Note: this method may be called from subprocess, so it does not
         change ``self`` object in any way!
@@ -257,12 +255,14 @@ class TestRunner(ContextManager['TestRunner']):
 
         args = [str(f_test.resolve())]
         env = self.env.prepare_subprocess(args)
-        if mp:
-            # Split test directories, so that tests running in parallel don't
-            # break each other.
-            for d in ['TEST_DIR', 'SOCK_DIR']:
-                env[d] = os.path.join(env[d], f_test.name)
-                Path(env[d]).mkdir(parents=True, exist_ok=True)
+
+        # Split test directories, so that tests running in parallel don't
+        # break each other.
+        for d in ['TEST_DIR', 'SOCK_DIR']:
+            env[d] = os.path.join(
+                env[d],
+                f"{self.env.imgfmt}-{self.env.imgproto}-{f_test.name}")
+            Path(env[d]).mkdir(parents=True, exist_ok=True)
 
         test_dir = env['TEST_DIR']
         f_bad = Path(test_dir, f_test.name + '.out.bad')
@@ -347,7 +347,7 @@ class TestRunner(ContextManager['TestRunner']):
             testname = os.path.basename(test)
             print(f'# running {self.env.imgfmt} {testname}')
 
-        res = self.do_run_test(test, mp)
+        res = self.do_run_test(test)
 
         end = datetime.datetime.now().strftime('%H:%M:%S')
         self.test_print_one_line(test=test,