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.