SCSI (experimental)

crosvm supports virtio-scsi devices that work as block devices for the guest.

The step for setting up a block device is similar to the virtio-blk device. After setting up the block device, pass it with --scsi-block flag so the disk will be exposed as /dev/sda, /dev/sdb, etc. The device can be mounted with the mount command.

crosvm run \
  --scsi-block disk.img
  ... # usual crosvm args

Flags & Options

The --scsi-block parameter supports additional options and flags to enable features and control disk parameters.


To expose the scsi device as a read-only disk, you can add the ro flag after the disk image path:

crosvm run \
  --scsi-block disk.img,ro
  ... # usual crosvm args


If you use a scsi device as guest's rootfs, you can add the root flag to the --scsi-block parameter:

crosvm run \
  --scsi-block disk.img,root
  ... # usual crosvm args

This flag automatically adds a root=/dev/sdX kernel parameter with the corresponding virtio-scsi device name and read-only (ro) or read-write (rw) option depending on whether the ro flag has also been specified or not.

Block size

  • Syntax: block_size=BYTES
  • Default: block_size=512

The block_size option overrides the reported block size (also known as sector size) of the virtio-scsi device. This should be a power of two larger than or equal to 512.