arm/lib: Specify the FVP environment variables explicitly

It is sometimes useful to be able to configure the behavior of FVPs
using environment variables, e.g. for licensing or plugins.

Add a new FVP option: FVP_ENV_PASSTHROUGH, which allows the Bitbake
variables to be passed to the environment to be specified explicitly (in
a similar way to BB_ENV_PASSTHROUGH). This ensures that:

 * FVPs launched via runfvp have a reproducable environment
 * FVPs launched via testimage (which run from an isolated Bitbake task)
   can receive environment variables

Change the self-tests to use cwd instead of PATH to find the mock FVPs,
as the PATH environment variable is no longer passed through.

Issue-Id: SCM-4964
Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>
Change-Id: Idf6ac6d41fda4cd5f950bc383c2fc1fa1acdf4e3
Signed-off-by: Jon Mason <jon.mason@arm.com>

documentation/runfvp.md

@@ -116,6 +116,14 @@ Arbitrary extra arguments that are passed directly to the FVP.  For example:
 FVP_EXTRA_ARGS = "--simlimit 60"
 ```
 
+### `FVP_ENV_PASSTHROUGH`
+
+The FVP is launched with an isolated set of environment variables. Add the name of a Bitbake variable to this list to pass it through to the FVP environment. For example:
+
+```
+FVP_ENV_PASSTHROUGH = "ARMLMD_LICENSE_FILE FM_TRACE_PLUGINS"
+```
+
 
 [AEM]: https://developer.arm.com/tools-and-software/simulation-models/fixed-virtual-platforms/arm-ecosystem-models
 [FVP]: https://developer.arm.com/tools-and-software/simulation-models/fixed-virtual-platforms

meta-arm/classes/fvpboot.bbclass

@@ -23,6 +23,8 @@ FVP_CONSOLE ?= ""
 FVP_CONSOLES[default] ?= "${FVP_CONSOLE}"
 # Arbitrary extra arguments
 FVP_EXTRA_ARGS ?= ""
+# Bitbake variables to pass to the FVP environment
+FVP_ENV_PASSTHROUGH ?= ""
 
 EXTRA_IMAGEDEPENDS += "${FVP_PROVIDER}"
 
@@ -66,6 +68,10 @@ python do_write_fvpboot_conf() {
     data["terminals"] = getFlags("FVP_TERMINALS")
     data["args"] = shlex.split(d.getVar("FVP_EXTRA_ARGS") or "")
 
+    data["env"] = {}
+    for var in d.getVar("FVP_ENV_PASSTHROUGH").split():
+        data["env"][var] = d.getVar(var)
+
     os.makedirs(os.path.dirname(conffile), exist_ok=True)
     with open(conffile, "wt") as f:
         json.dump(data, f)

meta-arm/lib/fvp/conffile.py

@@ -51,6 +51,7 @@ def load(config_file):
     sanitise("terminals", {})
     sanitise("args", [])
     sanitise("consoles", {})
+    sanitise("env", {})
 
     if not config["exe"]:
         raise ValueError("Required value FVP_EXE not set in machine configuration")

meta-arm/lib/fvp/runner.py

@@ -60,7 +60,10 @@ class FVPRunner:
         cli = cli_from_config(config, terminal_choice)
         cli += extra_args
         self._logger.debug(f"Constructed FVP call: {cli}")
-        self._fvp_process = await asyncio.create_subprocess_exec(*cli, stdin=subprocess.DEVNULL, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+        self._fvp_process = await asyncio.create_subprocess_exec(
+            *cli,
+            stdin=subprocess.DEVNULL, stdout=subprocess.PIPE, stderr=subprocess.STDOUT,
+            env=config['env'])
 
         def detect_terminals(line):
             m = re.match(r"^(\S+): Listening for serial connection on port (\d+)$", line)

meta-arm/lib/oeqa/selftest/cases/runfvp.py

@@ -20,11 +20,10 @@ class RunFVPTests(OESelftestTestCase):
         on exit code 0 or fail the test, otherwise return the CompletedProcess
         instance.
         """
-        # Put the test directory in PATH so that any mock FVPs are found first
-        newenv = {"PATH": str(testdir) + ":" + os.environ["PATH"]}
         cli = [runfvp,] + list(args)
         print(f"Calling {cli}")
-        ret = subprocess.run(cli, env=newenv, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, universal_newlines=True)
+        # Set cwd to testdir so that any mock FVPs are found
+        ret = subprocess.run(cli, cwd=testdir, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, universal_newlines=True)
         if should_succeed:
             self.assertEqual(ret.returncode, 0, f"runfvp exit {ret.returncode}, output: {ret.stdout}")
             return ret.stdout
@@ -40,8 +39,6 @@ class RunFVPTests(OESelftestTestCase):
         self.run_fvp("--this-is-an-invalid-option", should_succeed=False)
 
     def test_run_auto_tests(self):
-        newenv = {"PATH": str(testdir) + ":" + os.environ["PATH"]}
-
         cases = list(testdir.glob("auto-*.json"))
         if not cases:
             self.fail("No tests found")
@@ -79,6 +76,7 @@ class ConfFileTests(OESelftestTestCase):
             self.assertTrue("terminals" in conf)
             self.assertTrue("args" in conf)
             self.assertTrue("consoles" in conf)
+            self.assertTrue("env" in conf)
 
 
 class RunnerTests(OESelftestTestCase):
@@ -97,6 +95,7 @@ class RunnerTests(OESelftestTestCase):
                 "applications": {'a1': 'file'},
                 "terminals": {},
                 "args": ['--extra-arg'],
+                "env": {"FOO": "BAR"}
             }))
 
             m.assert_called_once_with('/usr/bin/FVP_Binary',
@@ -106,4 +105,5 @@ class RunnerTests(OESelftestTestCase):
                 '--extra-arg',
                 stdin=unittest.mock.ANY,
                 stdout=unittest.mock.ANY,
-                stderr=unittest.mock.ANY)
+                stderr=unittest.mock.ANY,
+                env={"FOO":"BAR"})

meta-arm/lib/oeqa/selftest/cases/tests/auto-basic.json

@@ -1,3 +1,4 @@
 {
+    "fvp-bindir": ".",
     "exe": "auto-basic.sh"
 }

meta-arm/lib/oeqa/selftest/cases/tests/auto-parameters.json

@@ -1,4 +1,5 @@
 {
+    "fvp-bindir": ".",
     "exe": "test-parameters.py",
     "parameters": {
         "board.cow": "moo",

meta-arm/lib/oeqa/selftest/cases/tests/test-parameter.json

@@ -1,4 +1,5 @@
 {
+    "fvp-bindir": ".",
     "exe": "test-parameters.py",
     "parameters": {
         "board.cow": "moo"