Sent: Thursday, October 15, 2020 at 2:01 PM From: "Peter Krempa" <pkrempa@redhat.com> To: "daggs" <daggs@gmx.com> Cc: "libvirt-usersredhat.com" <libvirt-users@redhat.com> Subject: Re: scsi passthrough differs between guests
[...]
-drive file=/dev/sg5,if=none,format=raw,id=drive-hostdev0,readonly=on \ -device scsi-generic,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-hostdev0,id=hostdev0 \
[...]
the bad one: /usr/bin/qemu-system-x86_64 \
[...]
-blockdev '{"driver":"host_device","filename":"/dev/sg0","node-name":"libvirt-hostdev0-backend","read-only":true}' \ -device scsi-generic,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=libvirt-hostdev0-backend,id=hostdev0 \
This doesn't corelate with the version numbers you've mentioned, because the "new" syntax which uses -blockdev was present both in 6.7.0 and 6.8.0.
Greetings Peter, the "good" syntax was created with libvirt of version which is earlier than 6.7, libvirt was upgraded several times since the vm creation. I don't know if the syntax is changed every version or not.
Anyways the problem is almost certainly that the hostdev code doesn't detect that it's a cdrom. We have such a hack in the disk code which turns a 'host_device' into a 'host_cdrom'. I'll try fixing it but I don't have a machine with a cdrom handy, so it would be nice if you could test it afterwards.
Thanks for the report.
my system is gentoo, hence, every pkg is compiled, if you provide a patch, I can test it easily. Thanks for the effort, Dagg.