On Mon, Mar 10, 2025 at 10:10:53AM +0100, Peter Krempa wrote:
On Mon, Mar 10, 2025 at 09:05:28 +0000, Daniel P. Berrangé wrote:
> On Sat, Mar 08, 2025 at 02:57:41PM +0900, Akihiko Odaki wrote:
> > usb-storage is a compound device that automatically creates a USB mass
> > storage device and a SCSI device as its backend. Unfortunately it lacks
> > some configuration options that are usually present with a SCSI device,
> > and cannot represent CD-ROM in particular.
> >
> > Replace usb-storage with usb-bot, which can be combined with a manually
> > created SCSI device. libvirt will configure the SCSI device in a way
> > identical with how QEMU does for usb-storage except that now it respects
> > a configuration option to represent CD-ROM.
>
> Is this change compatible for QEMU's VMState aka migration ABI compatible ?
Based on my tests so far it seems compatible in terms of VMstate and
also guest ABI at least to the first glance (lsusb, lsscsi -v etc) seems
identical at least for the default 'read-write'/non-cdrom disk.
I didn't yet test migrating with a cdrom to an older daemon though,
which based on the above paragraph should have guest-visible difference.
Any such configuratin of the latter is arguably a bug though ? It was
never presenting a cdrom, and that we allowed it was just a sign of
missing XML validation surely ?
With regards,
Daniel
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