[RFC PATCH v1 3/5] dts: add class for virtual functions

[jspewock@iol.unh.edu]

From: Jeremy Spewock <jspewock@iol.unh.edu>

In DPDK applications virtual functions are treated the same as ports,
but within the framework there are benefits to differentiating the two
in order to add more metadata to VFs about where they originate from.
For this reason this patch adds a new class for handling virtual
functions that extends the Port class with some additional information
about the VF.

Bugzilla ID: 1500

Signed-off-by: Jeremy Spewock <jspewock@iol.unh.edu>
---
 dts/framework/testbed_model/port.py | 37 ++++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/dts/framework/testbed_model/port.py b/dts/framework/testbed_model/port.py
index 817405bea4..c1d85fec2b 100644
--- a/dts/framework/testbed_model/port.py
+++ b/dts/framework/testbed_model/port.py
@@ -27,7 +27,7 @@ class PortIdentifier:
     pci: str
 
 
-@dataclass(slots=True)
+@dataclass
 class Port:
     """Physical port on a node.
 
@@ -80,6 +80,41 @@ def pci(self) -> str:
         return self.identifier.pci
 
 
+@dataclass
+class VirtualFunction(Port):
+    """Virtual Function (VF) on a port.
+
+    DPDK applications often treat VFs the same as they do the physical ports (PFs) on the host.
+    For this reason VFs are represented in the framework as a type of port with some additional
+    metadata that allows the framework to more easily identify which device the VF belongs to as
+    well as where the VF originated from.
+
+    Attributes:
+        created_by_framework: :data:`True` if this VF represents one that the DTS framework created
+            on the node, :data:`False` otherwise.
+        pf_port: The PF that this VF was created on/gathered from.
+    """
+
+    created_by_framework: bool = False
+    pf_port: Port | None = None
+
+    def __init__(
+        self, node_name: str, config: PortConfig, created_by_framework: bool, pf_port: Port
+    ) -> None:
+        """Extends :meth:`Port.__init__` with VF specific metadata.
+
+        Args:
+            node_name: The name of the node the VF resides on.
+            config: Configuration information about the VF.
+            created_by_framework: :data:`True` if DTS created this VF, otherwise :data:`False` if
+                this class represents a VF that was preexisting on the node.
+            pf_port: The PF that this VF was created on/gathered from.
+        """
+        super().__init__(node_name, config)
+        self.created_by_framework = created_by_framework
+        self.pf_port = pf_port
+
+
 @dataclass(slots=True, frozen=True)
 class PortLink:
     """The physical, cabled connection between the ports.
-- 
2.46.0