New function to kernel_disk_workload to allow new disk device location (#151)

Added a parameter (_disk_device) to kernel_disk_workload which allows
users to change the disk device location. get_disk_device() now chooses
between the parameter and, if no parameter was passed, it calls a new
function _get_default_disk_device() which is implemented by each board
and has a default disk device according to each board, eg /dev/hda in
the x86_board. The previous way of setting a disk device still exists as
a default, however, with the new function users can now override this
default

src/python/gem5/components/boards/arm_board.py

@@ -386,6 +386,7 @@ class ArmBoard(ArmSystem, AbstractBoard, KernelDiskWorkload):
             "lpj=19988480",
             "norandmaps",
             "root={root_value}",
+            "disk_device={disk_device}",
             "rw",
             f"mem={self.get_memory().get_size()}",
         ]

src/python/gem5/components/boards/experimental/lupv_board.py

@@ -534,14 +534,19 @@ class LupvBoard(AbstractSystemBoard, KernelDiskWorkload):
         fdt.writeDtsFile(os.path.join(outdir, "device.dts"))
         fdt.writeDtbFile(os.path.join(outdir, "device.dtb"))
 
-    @overrides(KernelDiskWorkload)
-    def get_default_kernel_args(self) -> List[str]:
-        return ["console=ttyLIO0", "root={root_value}", "rw"]
-
     @overrides(KernelDiskWorkload)
     def get_disk_device(self) -> str:
         return "/dev/lda"
 
+    @overrides(KernelDiskWorkload)
+    def get_default_kernel_args(self) -> List[str]:
+        return [
+            "console=ttyLIO0",
+            "root={root_value}",
+            "disk_device={disk_device}",
+            "rw",
+        ]
+
     @overrides(KernelDiskWorkload)
     def _add_disk_to_board(self, disk_image: AbstractResource) -> None:
         # Note: This must be called after set_workload because it looks for an

src/python/gem5/components/boards/kernel_disk_workload.py

@@ -87,7 +87,7 @@ class KernelDiskWorkload:
     @abstractmethod
     def get_disk_device(self) -> str:
         """
-        Get the disk device, e.g., "/dev/sda", where the disk image is placed.
+        Set a default disk device, in case user does not specify a disk device.
 
         :returns: The disk device.
         """
@@ -139,6 +139,7 @@ class KernelDiskWorkload:
         kernel: KernelResource,
         disk_image: DiskImageResource,
         bootloader: Optional[BootloaderResource] = None,
+        disk_device: Optional[str] = None,
         readfile: Optional[str] = None,
         readfile_contents: Optional[str] = None,
         kernel_args: Optional[List[str]] = None,
@@ -171,6 +172,9 @@ class KernelDiskWorkload:
         # Abstract board. This function will not work otherwise.
         assert isinstance(self, AbstractBoard)
 
+        # Set the disk device
+        self._disk_device = disk_device
+
         # If we are setting a workload of this type, we need to run as a
         # full-system simulation.
         self._set_fullsystem(True)
@@ -182,7 +186,12 @@ class KernelDiskWorkload:
         self.workload.command_line = (
             " ".join(kernel_args or self.get_default_kernel_args())
         ).format(
-            root_value=self.get_default_kernel_root_val(disk_image=disk_image)
+            root_value=self.get_default_kernel_root_val(disk_image=disk_image),
+            disk_device=(
+                self._disk_device
+                if self._disk_device
+                else self.get_disk_device()
+            ),
         )
 
         # Setting the bootloader information for ARM board. The current

src/python/gem5/components/boards/riscv_board.py

@@ -494,4 +494,9 @@ class RiscvBoard(AbstractSystemBoard, KernelDiskWorkload):
 
     @overrides(KernelDiskWorkload)
     def get_default_kernel_args(self) -> List[str]:
-        return ["console=ttyS0", "root={root_value}", "rw"]
+        return [
+            "console=ttyS0",
+            "root={root_value}",
+            "disk_device={disk_device}",
+            "rw",
+        ]

src/python/gem5/components/boards/x86_board.py

@@ -318,4 +318,5 @@ class X86Board(AbstractSystemBoard, KernelDiskWorkload):
             "console=ttyS0",
             "lpj=7999923",
             "root={root_value}",
+            "disk_device={disk_device}",
         ]

src/python/gem5/prebuilt/riscvmatched/riscvmatched_board.py

@@ -566,7 +566,12 @@ class RISCVMatchedBoard(
 
     @overrides(KernelDiskWorkload)
     def get_default_kernel_args(self) -> List[str]:
-        return ["console=ttyS0", "root={root_value}", "rw"]
+        return [
+            "console=ttyS0",
+            "root={root_value}",
+            "disk_device={disk_device}",
+            "rw",
+        ]
 
     @overrides(KernelDiskWorkload)
     def set_kernel_disk_workload(