Re: [PATCH] blockdev: add 'media=cdrom' argument to support usb cdrom emulated as cdrom

[Zhipeng Lu]

Thanks.

 -device usb-bot,id=bot0
 -device scsi-{cd,hd},bus=bot0.0,drive=drive0

Qemu implements virtio scsi to emulate scsi controller, but if the 
virtual machine(for example windows guest os) don't install the virtio 
scsi driver, it don't work
i need the function: emulate cdrom in guest, support hotplug and unplug, 
not  depend on virtio driver

have a better idea?

在 2022/12/7 16:39, Paolo Bonzini 写道:
> It should be like this:
>
> -device usb-bot,id=bot0
> -device scsi-{cd,hd},bus=bot0.0,drive=drive0
>
> Libvirt has the code to generate the options for SCSI controllers, but 
> usb-bot only allows one disk attached to it so it's easier to make it a 
> <drive> element.
>
> Paolo
>
> Il sab 3 dic 2022, 13:52 Zhipeng Lu <luzhipeng@cestc.cn 
> <mailto:luzhipeng@cestc.cn>> ha scritto:
>
>     Could you give the detail qemu cmdline about usb-bot?
>
>     在 2022/12/2 17:40, Paolo Bonzini 写道:
>      > On 12/2/22 03:26, Zhipeng Lu wrote:
>      >> NAME          MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
>      >> sda             8:0    0  100M  1 disk
>      >> vda           252:0    0   10G  0 disk
>      >> ├─vda1        252:1    0    1G  0 part /boot
>      >> └─vda2        252:2    0    9G  0 part
>      >>    ├─rhel-root 253:0    0    8G  0 lvm  /
>      >>    └─rhel-swap 253:1    0    1G  0 lvm  [SWAP]
>      >> lshw -short|grep cdrom -i
>      >> No cdrom.
>      >>
>      >> My patch is to solve this problem, usb cdrom emulated as cdrom.
>      >
>      > This is a libvirt bug, it should use usb-bot instead of usb-storage
>      > together with -blockdev.  Then it can add a scsi-cd device below
>     usb-bot.
>      >
>      > Paolo
>      >
>      >>
>      >>
>      >> 在 2022/12/1 23:35, Markus Armbruster 写道:
>      >>> luzhipeng <luzhipeng@cestc.cn <mailto:luzhipeng@cestc.cn>> writes:
>      >>>
>      >>>> From: zhipeng Lu <luzhipeng@cestc.cn <mailto:luzhipeng@cestc.cn>>
>      >>>>
>      >>>> The drive interface supports media=cdrom so that the usb cdrom
>      >>>> can be emulated as cdrom in qemu, but libvirt deprived the drive
>      >>>> interface, so media=cdrom is added to the blockdev interface to
>      >>>> support usb cdrom emulated as cdrom
>      >>>>
>      >>>> Signed-off-by: zhipeng Lu <luzhipeng@cestc.cn
>     <mailto:luzhipeng@cestc.cn>>
>      >>>
>      >>> What problem are you trying to solve?
>      >>>
>      >>>
>      >>>
>      >>
>      >>
>      >>
>      >
>      >
>      >