On Thu, Oct 15, 2020 at 12:36:08 +0200, daggs wrote:
Greetings Peter,
Sent: Thursday, October 15, 2020 at 9:52 AM 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
I don't see anything wrong with you configs. There were some changes related to SCSI hostdevs, between 6.7.0 an 6.8.0, but none of them should actually impact that use case.
Said that, could you please post the actual qemu command lines that libvirt formatted for the two VMs you mention above.
The command line can be found in /var/log/libvirt/qemu/$VMNAME.log . Please make sure you post the latest/actual one. It'll help showing whether anything changed between the two or there is a different problem.
here is the good cmd: /usr/bin/qemu-system-x86_64 \
[...]
-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. 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.