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Re: [Qemu-devel] SCSI CD-ROM hotplug problem
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] SCSI CD-ROM hotplug problem |
Date: |
Thu, 25 Apr 2013 16:37:18 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Thu, Apr 25, 2013 at 01:40:41PM +0000, Liuji (Jeremy) wrote:
> I have a question about hotplug of cd-rom.
>
> version of qemu: Apr-22-2013 bb71623811686ce3c34ce724f073f5c5dd95f51b
>
> 1) start the vm:
> qemu-kvm -enable-kvm -m 1024 -smp 2 -boot c -drive
> file=/home/vm/winxp.qcow2,if=none,id=drive0,format=qcow2
> -device virtio-blk-pci,scsi=off,drive=drive0,id=disk0 -monitor stdio -vnc
> 186.100.8.136:1
> -device lsi,id=scsi0,bus=pci.0
The LSI SCSI controller is not actively maintained and has known issues
(see the bug tracker on launchpad). You're on your own if you use this
device.
> 2) use "drive_add" and "device_add" commands to hotplug a cd-rom:
> (qemu) drive_add 0
> file=/home/vm/aaa.iso,if=none,id=my-cdrom-drive,readonly=on,format=raw
> (qemu) device_add
> scsi-cd,bus=scsi0.0,scsi-id=2,drive=my-cdrom-drive,id=my-cdrom
>
> 3) but I can't find the new cd-rom in the WindowXP vm.
>
> 4) and then, I use "pci_add" command to hotplug another cd-rom:
> (qemu) pci_add auto storage
> file=/home/vm/bbb.iso,if=scsi,readonly=on,format=raw,media=cdrom
>
> 5) I not only found the second cd-rom, but also found first cd-rom in the
> WindowXP vm.
>
> When I only use "pci_add" command, I can hotplug a cd-rom successfully.
>
> Would you please tell me how to use "drive_add" and "device_add" commands to
> hotplug a cd-rom?
The reason why pci_add appears to work is because it hotplugs a new LSI
PCI adapter instead of just attaching a new SCSI CD-ROM to the existing
bus. You can check this by using the Device Manager in Windows to show
storage controllers/PCI adapters.
Perhaps the hotplug of a new adapter causes the Windows XP SCSI
subsystem to rescan all adapters...
Stefan