Dear Laine, Laine Stump <laine@xxxxxxxxx> writes: > On 09/07/2016 02:35 PM, Sascha Silbe wrote: >> "Daniel P. Berrange" <berrange@xxxxxxxxxx> writes: >> [...] >>> <sound model="virtio"/> == QEMU virtio >>> <sound model="virtio1.0"/> == QEMU virtio + disable-legacy >> What would this do for devices using the virtio-ccw transport? > > From libvirt's point of view, the option "disable-legacy=on" would be > added to the device's commandline argument. Which would break s390x guests. virtio-ccw doesn't have any concept of "legacy" or "modern" devices (that's purely a virtio-pci concept), so virtio-*-ccw devices don't recognise that switch: silbe@oc4731375738:~$ ~/build/qemu-devel/x86_64-softmmu/qemu-system-x86_64 -device virtio-blk,help 2>&1 |grep legacy virtio-blk-pci.disable-legacy=OnOffAuto (on/off/auto) silbe@oc4731375738:~$ ~/build/qemu-devel/s390x-softmmu/qemu-system-s390x -device virtio-blk,help 2>&1 |grep legacy That nicely illustrates the issue I have with a) mixing virtio-pci legacy/modern into the model name and b) conflating it with virtio 0.9/1.0 (or transitional/non-transitional for that matter). FWIW, the thing closest to virtio-pci legacy/modern is virtio-ccw max_revision. But I doubt there's any reason to set this beyond debugging and testing. > For the effect, you would > need to ask a qemu virtio person, or even better - a qemu s390 person > who knows something about about virtio. I Cc'ed Michael (the former) and > Cornelia Huck (the latter, according to this patch I found: > https://lists.gnu.org/archive/html/qemu-devel/2015-09/msg01024.html ) Thanks, but I'm working on qemu for s390x myself. :) Sascha -- Softwareentwicklung Sascha Silbe, Niederhofenstraße 5/1, 71229 Leonberg https://se-silbe.de/ USt-IdNr. DE281696641 -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list