VIOBLK(4D) Devices VIOBLK(4D)

NAME

vioblk - virtio block device

SYNOPSIS

/dev/dsk/cXt0d0 /dev/rdsk/cXt0d0

DESCRIPTION

The vioblk driver is a blkdev(4D) based device that supports the virtio
para-virtualization block device specification which is commonly used
by many hypervisors and emulators. The device supports what the
specification calls the more commonly found `legacy' interface for
devices.

The driver supports the following features, if offered by the device:

- Volatile write-cache

- Discarding unused sectors (ala TRIM, UNMAP)

- Read-only device support

- Physical block sizes that are distinct from logical 512-byte blocks

- Synthesized disk geometry

APPLICATION PROGRAMMING INTERFACE

For each device instance, a blkdev(4D) instance is created and treated
as an independent controller with a single device, meaning that the cX
part of cXt0d0 will vary for each device. Because the driver leverages
the blkdev(4D) framework, most standard disk manipulation utilities
will function such as diskinfo(8) for discovering devices, format(8)
for manipulating partition tables, iostat(8) for seeing device I/O
statistics, and a subset of the dkio(4I) ioctl requests to retrieve
information about the device.

ARCHITECTURE

The vioblk driver is only supported on x86.

FILES

/dev/dsk/cXt0d0 Block device minor node.

/dev/rdsk/cXt0d0 Character device minor node.

/kernel/drv/amd64/vioblk x86 device driver.

SEE ALSO

blkdev(4D), vioscsi(4D), virtio(4D), dkio(4I), diskinfo(8)

Virtual I/O Device (VIRTIO) Version 1.1,
https://docs.oasis-open.org/virtio/virtio/v1.1/virtio-v1.1.html, April,
2019.

illumos June 14, 2022 illumos