Re: [libvirt] [RFC PATCH 05/30] qemu: block: Extract formatting of props for 'file' backend

On Fri, Apr 20, 2018 at 10:41:50 +0200, Kevin Wolf wrote: > Am 20.04.2018 um 09:56 hat Peter Krempa geschrieben: > > Is there a special need to use 'host_cdrom' explicitly if the CDROM > > drive is used? That would complicate things since we don't know when > > that will happen. > > You don't get the full CD-ROM passthrough functionality with > host_device. Specifically, if you eject the virtual drive, the physical > drive will only be ejected with host_cdrom, and the same is true for > lock_medium. > > I think we may also make an attempt at detecting physical media change > ocassionally with host_cdrom, but I doubt that this is working reliably > anyway (the driver function is .bdrv_is_inserted, so it would be polling > rather than processing an event; and I'm not sure when it's called). Hmm, okay, it seems that we in fact should use it. Is there any drawback if host_cdrom is used with a device which is not a CDROM? (e.g. a logical volume containing the image?) Basically the question is whether we need to add some "smart" handling or we can just assume that if the guest device is a block-backed CDROM we can use that.