docs/usb-storage.txt

   1
   2 qemu usb storage emulation
   3 --------------------------
   4
   5 QEMU has three devices for usb storage emulation.
   6
   7 Number one emulates the classic bulk-only transport protocol which is
   8 used by 99% of the usb sticks on the market today and is called
   9 "usb-storage".  Usage (hooking up to xhci, other host controllers work
  10 too):
  11
  12   qemu ${other_vm_args}                                \
  13        -drive if=none,id=stick,file=/path/to/file.img  \
  14        -device nec-usb-xhci,id=xhci                    \
  15        -device usb-storage,bus=xhci.0,drive=stick
  16
  17
  18 Number two is the newer usb attached scsi transport.  This one doesn't
  19 automagically create a scsi disk, so you have to explicitly attach one
  20 manually.  Multiple logical units are supported.  Here is an example
  21 with tree logical units:
  22
  23   qemu ${other_vm_args}                                                \
  24        -drive if=none,id=uas-disk1,file=/path/to/file1.img             \
  25        -drive if=none,id=uas-disk2,file=/path/to/file2.img             \
  26        -drive if=none,id=uas-cdrom,media=cdrom,file=/path/to/image.iso \
  27        -device nec-usb-xhci,id=xhci                                    \
  28        -device usb-uas,id=uas,bus=xhci.0                               \
  29        -device scsi-hd,bus=uas.0,scsi-id=0,lun=0,drive=uas-disk1       \
  30        -device scsi-hd,bus=uas.0,scsi-id=0,lun=1,drive=uas-disk2       \
  31        -device scsi-cd,bus=uas.0,scsi-id=0,lun=5,drive=uas-cdrom
  32
  33
  34 Number three emulates the classic bulk-only transport protocol too.
  35 It's called "usb-bot".  It shares most code with "usb-storage", and
  36 the guest will not be able to see the difference.  The qemu command
  37 line interface is simliar to usb-uas though, i.e. no automatic scsi
  38 disk creation.  It also features support for up to 16 LUNs.  The LUN
  39 numbers must be continuous, i.e. for three devices you must use 0+1+2.
  40 The 0+1+5 numbering from the "usb-uas" example isn't going to work
  41 with "usb-bot".
  42
  43 enjoy,
  44   Gerd
  45
  46 --
  47 Gerd Hoffmann <kraxel@redhat.com>