usb: add storage hotplug documentation

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 1466667901-1341-1-git-send-email-kraxel@redhat.com
This commit is contained in:
Gerd Hoffmann 2016-06-23 09:45:01 +02:00
parent a4055d8586
commit b91e013982

View File

@ -40,6 +40,18 @@ numbers must be continuous, i.e. for three devices you must use 0+1+2.
The 0+1+5 numbering from the "usb-uas" example isn't going to work
with "usb-bot".
Starting with qemu version 2.7 usb-bot and usb-uas devices can be
hotplugged. In the hotplug case they are added with "attached =
false" so the guest will not see the device until the "attached"
property is explicitly set to true. That allows to attach one or more
scsi devices before making the device visible to the guest, i.e. the
workflow looks like this:
(1) device-add usb-bot,id=foo
(2) device-add scsi-{hd,cd},bus=foo.0,lun=0
(2b) optionally add more devices (luns 1 ... 15).
(3) scripts/qmp/qom-set foo.attached = true
enjoy,
Gerd