A new version of the virtio specification has been released! As it has been three years after the 1.1 release, quite a lot of changes have accumulated. I have attempted to list some of them below; for details, you are invited to check out the spec :)

There are already some changes queued for 1.3; let’s hope it won’t take us three years again before the next release ;)

New device types in 1.2

Several new device types have been added.

• virtio-pmem: persistent memory device; useful to avoid a separate page cache in the guest
• virtio-fs: access a file system; kind of the spritual successor to the never officially standardized virtio-9p
• virtio-rpmb: a tamper-resistant and anti-replay storage device
• virtio-iommu: can both be a proxy for a physical IOMMU, or act as a virtual IOMMU
• virtio-snd: a sound card supporting input and output PCM streams
• virtio-mem: provides a memory region in guest physical address space; useful to implement memory hot(un)plugging
• virtio-i2c: a virtual I2C adapter
• virtio-scmi: implements the Arm System Control and Management Interface, for things like sensors etc.
• virtio-gpio: a virtual GPIO device to manage named I/O lines

New features for existing device types

Enhancements have been added to some already existing device types.

• virtio-blk
  • multiqueue support
  • lifetime metrics
  • secure erase
• virtio-net
  • support for the guest providing the exact header length
  • receive-side scaling
  • per-packet hash reporting
  • per-virtqueue driver notifications
  • UDP segmentation offload
• virtio-gpu
  • support for 3D commands
  • resource sharing
  • blob resources
  • context initialization
• virtio-balloon
  • free page hints
  • page poisoning
  • free page reporting
• virtio-vsock
  • seqpacket sockets

Features not specific to a device type

Some general enhancements include:

• support for vendor-specific PCI capabilities
• support for sharing resources between devices
• support for resetting individual virtqueues