Add ability to include a plugin when creating driver

.github/workflows/test_models.yml

@@ -52,6 +52,7 @@ jobs:
           pip install --no-compile -r ${{ github.workspace }}/iree-turbine/pytorch-cpu-requirements.txt
           pip install --no-compile --pre --upgrade -r ${{ github.workspace }}/iree-turbine/requirements.txt
           pip install --no-compile --pre -e ${{ github.workspace }}/iree-turbine[testing]
+          pip install --upgrade --pre --no-cache-dir iree-compiler iree-runtime -f https://iree.dev/pip-release-links.html
           pip install --no-compile --pre --upgrade -e models -r models/requirements.txt
 
       - name: Show current free memory

models/turbine_models/model_runner.py

@@ -1,12 +1,24 @@
 import argparse
 import sys
 from iree import runtime as ireert
+from iree.runtime._binding import create_hal_driver
 
 
 class vmfbRunner:
-    def __init__(self, device, vmfb_path, external_weight_path=None):
+    def __init__(self, device, vmfb_path, external_weight_path=None, extra_plugin=None):
         flags = []
-        haldriver = ireert.get_driver(device)
+
+        # If an extra plugin is requested, add a global flag to load the plugin
+        # and create the driver using the non-caching creation function, as
+        # the caching creation function may ignore the flag.
+        if extra_plugin:
+            ireert.flags.parse_flags(f"--executable_plugin={extra_plugin}")
+            haldriver = create_hal_driver(device)
+
+        # No plugin requested: create the driver with the caching create
+        # function.
+        else:
+            haldriver = ireert.get_driver(device)
         if "://" in device:
             try:
                 device_idx = int(device.split("://")[-1])