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(Virtual) Device | Explanation | Champion | Completeness / Applicability evaluation
| Comments and discussion |
---|---|---|---|---|
Block Storage | Flash/Disk/persistent storage | Kai | Possibly definition not enough since it is very generic. What happens below when the challenges Kai working on evaluating these details. Let's investigate practical implementation of TRIM command, as example. | |
Network | Access to (shared) physical ethernet and guest-to-guest communication | Nikola ( w.r.t. AVB, see below)AvB only)
| ||
Console | Text terminal input | Gunnar | Done initial browsing of the specification. Opinions still pending. | |
crypto | Access to cryptographic services (hardware accelerated) | Sang-bum | ||
GPU | Graphics hardware | Matti/Dmitry | See GPU Summary, VIRTIO GPU Operation Highlights pages | See GPU Summary page |
Input | Traditionally keyboard/mouse/etc - for automotive = expanded? | Matti | ||
vsock | Communication between guest (VM) and host (hypervisor) | |||
9pfs | 9P = protocol to expose host (hypervisor) file systems to the guest. FS=filesystem. | Gunnar | Use-cases: ? Completeness: Protocol: Need in Embedded/Automotive: Applicability: |
Essentially used for "shared folder" capability between host & guest, as in desktop (or maybe some server) usage. Its applicability to embedded hypervisor usage, in which the "host" is not really being used by itself) seems questionable. What's the use-case? In VIRTIO spec: A PCI type device can indicate that it is going to use the 9P protocol. The specification also has 9P as a specific separate device type. Other than that, I found no further description of such a device type. The protocol is specified elsewhere and complemented by scattered information regarding the specific implementations (Xen, KVM, QEMU, ...) The protocol seems proven and supposedly OK for what it does. Possibly more security features needed, depending on use-case. VIRTIO however seems to defer the definition completely to "somewhere else"? At least a reference to a canonical specification would seem appropriate. It is a minimalistic network file-system protocol. It seems apt for the task. Other network protocols like NFS, SMB/SAMBA etc. would be too heavy. It feels a bit esoteric, and while "reinventing" is bad, in this simple case would not be the worst ever, if VIRTIO had defined something else. Flexibility and security features seem somewhat glossed over. There's basically only "fixed user" or "pass-through" for mapping ownership on files in guest/host. Links: Virtio 1.0 spec : {PCI-9P, 9P device type}. A note on its documentation/definition not being very precise A set of man pages seemingly defining P9? intro, others QEMU instruction how to set up a VirtFS (P9). |
Example how to set up in Linux system | ||||
vIOMMU | IOMMU coordinates of DMA devices' | Dmitry | See IOMMU Summary page | |
Audio | Matti | Some info on Linux/Xen code here: HVWS: Xen input and experience on Audio, Display, Input and TEE | ||
Sensors | Automotive sensors: | Artem | Automotive sensors? Radar/LiDAR/? (or are they separate ECUs?) Standard embedded sensor (ambient light...) Some OS have requirements - eg. Android requires orientation sensor. CPUs/SoCs have "internal" sensors too. Relating to temperature and power mgmt. Some internal control tweaks for power management (core frequency / voltage) are like tiny internal actuators. Virtual access to those? Same or different APIs? | Artem proposed that Systems Control Management Interface (SCMI) protocol is flexible and an appropriate abstraction for sensors. It is also appropriate for controlling power-management and related things. The hardware access implementation is according to ARM offloaded to a "Systems Control Processor" but this is a virtual concept. It could be a dedicated core in some cases, perhaps in others not. EPAM/Xen tried out putting code in ARM-TF, to act as this SCP. SCMI destined (?) to become a ARM-wide standard in a currently fragmented reality. Upper protocol defined, but could imagine different lower transport. One mailbox-style transport is kind-of defined by ARM spec? Discussion if VIRTIO transport would be appropriate. A "SCMI device" type added to VIRTIO? Challenges:
Reference:
What about PINCTRL, and handling the many multiplexed pins in a modern SoC. Any remaining need for lower-level protocols for accessing/virtualizing hardware? |
Media Acceleration (VPUP, IPU, CODEC) | Hardware support for codec/processing Abstraction of SoC specifics DSPs Tensor processors | Artem | VPU = "AI" CPU optimized for visual recognition | |
USB | Franz | Example Assigning Host USB device to a Guest VM in KVM, here:https://www.linux-kvm.org/page/USB_Host_Device_Assigned_to_Guest | Which use cases do we want to address? •USB 2.0 (EHCI controller)
•On-The-Go (system can function as both USB host and USB device)
| |
Other Serial devices? (Where does LIN, etc. fit in?) | LIN-bus:
| |||
CAN | Franz | virtio-can: VIRTIO-based CAN driver | ||
Ethernet (incl. AvB/TSN) | Nikola | The required features are not present in the network virtio devices as of virtio 1.0. | Must have requirements:
Good to have:
General architectural considerations:
| |
Bluetooth | Sang-bum +OpenSynergy with BT experience | Is it possible? Needed? | ||
Memory Balloon Device | Applicable? |
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