Re: [libvirt] [PATCH V3 2/3] virtio-blk: fail get_features when both scsi and 1.0 were set

On 22/07/2015 13:46, Daniel P. Berrange wrote: > IIUC, the SCSI passthrough feature for virtio-blk is enabled by > setting the 'scsi=on' property on the virtio-blk device, which is > exposed by libvirt with XML: > > <disk type='block' device='lun'> > <driver name='qemu' type='raw'/> > <source dev='/dev/sda'/> > <target dev='vda' bus='virtio'/> > </disk> > > (For use with virtio-scsi you'd just change the <target> element) > > So if the guest is using virtio-1.0, then this will now fail to boot, or > cause an error from monitor hotplug. This is not too bad, but I'm just > wondering if there's anything else we ought to think about doing in libvirt > in this situation. Normally we'd try to detect unsupported things upfront > so we can report VIR_ERR_CONFIG_UNSUPPORTED, instead of the generic error > code VIR_ERR_INTERNAL_ERROR, but perhaps this is sufficiently niche to > not worry about it and its fine to just delegate error reporting to QEMU ? Probably. Note that it will be a long time before the default is changed to 1.0 (if it ever will).

Perhaps you can start warning now about <disk type='block' device='lun'>, and suggest using virtio-scsi instead? Paolo