Re: [Qemu-devel] [libvirt] [PATCH 3/5] qemu: add usb-bot support from disks points of view

[Daniel P. Berrange]

On Mon, Sep 02, 2013 at 05:38:42PM +0800, Guannan Ren wrote:
> usb-bot only supports 16 luns(0~15) and they must be contiguous,
> (using lun 0 and 2 without 1 doesn't work). In this case qemu
> doesn't throw an error, we can not find the lun 2 in guests. So
> Adding a checking function in libvirt to prevent from this case.

Hmm, this seems like a problematic restriction.

How does this work if we start off a guest with 3 disks
attached to the usb-bot SCSI controller. Then hot-unplug
the 2nd disk.

Next time we need will need to start with with LUNs 0
and 2 populated only, otherwise we have ABI change upon
migrate or save/restore.

I think this restriction about contiguous luns must be
removed if this device is to be usable with multiple luns.

Daniel
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