VirtIO

VirtIO is a standard for performant virtualized hardware for use within virtual machines, created and managed by the OASIS Open Virtual I/O Device TC. VirtIO supports a variety of devices, such as, but not limited to: block (e.g. hard drive), network card, GPU, etc. Each of these devices have their own specific configuration and features, but all use the same underlying VirtIO queue structure for relaying data and commands to & from the device.

Device Types

VirtIO Device Types

Device ID	Device Name	Description
0	reserved (invalid)	TODO
1	network card	TODO
2	block device	TODO
3	console	TODO
4	entropy source	TODO
5	memory ballooning (traditional)	TODO
6	ioMemory	TODO
7	rpmsg	TODO
8	SCSI host	TODO
9	9P transport	TODO
10	mac80211 wlan	TODO
11	rproc serial	TODO
12	virtio CAIF	TODO
13	memory balloon	TODO
16	GPU device	TODO
17	Timer/Clock device	TODO
18	Input device	TODO
19	Socket device	TODO
20	Crypto device	TODO
21	Signal Distribution Module	TODO
22	pstore device	TODO
23	IOMMU device	TODO
24	Memory device	TODO
25	Audio device	TODO
26	file system device	TODO
27	PMEM device	TODO
28	RPMB device	TODO
29	mac80211 hwsim wireless simulation device	TODO
30	Video encoder device	TODO
31	Video decoder device	TODO
32	SCMI device	TODO
33	NitroSecureModule	TODO
34	I2C adapter	TODO
35	Watchdog	TODO
36	CAN device	TODO
38	Parameter Server	TODO
39	Audio policy device	TODO
40	Bluetooth device	TODO
41	GPIO device	TODO
42	RDMA device	TODO

Device Transports

VirtIO supports three different types of device transports: PCI Bus, MMIO, and Channel I/O. The PCIe transport is configured via the normal PCIe configuration mechanisms, while the MMIO transport is configured strictly via MMIO reads and writes.