On 22/07/2015 12:19, Michael S. Tsirkin wrote: > > > SCSI passthrough was no longer supported in virtio 1.0, so this patch > > > fail the get_features() when both 1.0 and scsi is set. And also only > > > advertise VIRTIO_BLK_F_SCSI for legacy virtio-blk device. > > > > Why is SCSI passthrough support not available in virtio 1.0 ? This > > will cause a regression for any users of that as & when QEMU changes > > to use virtio 1.0 by default. Can we not fix this regression instead. > > If we wanted to, we might be able to fix this but not for 2.4: we'd have > to extend the spec and guest drivers, in some way TBD. > > Paolo would be best placed to answer whether this feature is desirable > in the future, I think the argument made when the spec was written was that > the feature is not widely used, and virtio scsi is available as > a replacement for people who need it.
No, the feature is not desirable in the future. There is no reason really not to use virtio-scsi passthrough instead, since virtio-scsi has been out for about 3 years now and is stable. In addition, the implementation would either not be compatible with virtio 0.9, or would be different from everything else in the spec because it requires a particular framing for the buffers. Paolo
