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3.2 Network Device
Standard networks
Standard networks include those that are not automotive specific, but instead frequently used in the computing world. In other words these are typically IP based networks, but some of them simulate this level through other means (e.g. vsock which does not use IP addressing). The physical layer is normally some variation of the Ethernet/WiFi standard(s) (according to standards 802.*) or other transport that transparently exposes a similar network socket interface
virtio-net = Layer 2 (Ethernet / MAC addresses)
virtio-vsock = Layer 4. Has its own socket type. Optimized by stripping away the IP stack. Possibility to address VMs without using IP addresses. Primary function is Host (HV) to VM communication.
Discussion:
Vsock: Each VM has logical ID but the VM normally does not know about it. Example usage: Running a particular agent in the VM that does something on behalf of the HV. There is also the possibility to use this for VM-to-VM communication, but since this is a special socket type it would involve writing code that is custom for the virtualization case, as opposed to native.
vsock is the application API. Multiple different named transport variations exist in different hypervisors which means the driver implementation differs depending on chosen hypervisor. Virtio-vsock however locks this down to one chosen method.
Requirements:
- If the platform implements virtual networking, it shall also use the virtio-net required interface between drivers and Hypervisor.
- If the platform implements vsock, it shall also use the virtio-vsock required API between drivers and Hypervisor.
- Virtual network interfaces shall be exposed as the operating system's standard network interface concept, i.e. they should show up as a normal network device.
- The hypervisor/equivalent shall provide the ability to dedicate and expose any hardware network interface to one virtual machine.
- The hypervisor/equivalent shall(?) be able to configure virtual inter-vm networking interfaces.
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Parked questions
- What could a common test suite look like?
- Google virtual ethernet driver - merged into mainline?
1. Introduction
Automotive requirements lead to particular choices and needs from the underlying software stack. Existing standards for device drivers in virtualization need to be augmented because they are often not focused on automotive or even embedded, systems. Much of the progression comes from the IT/server consolidation and in the Linux world, some come from virtualization of workstation/desktop systems.
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