On Mon, Aug 03, 2020 at 11:26 AM +0200, Cornelia Huck <[email protected]> wrote: > On Thu, 30 Jul 2020 16:07:31 +0200 > Marc Hartmayer <[email protected]> wrote: > >> Since virtio existed even before it got standardized, the virtio >> standard defines the following types of virtio devices: >> >> + legacy device (pre-virtio 1.0) >> + non-legacy or VIRTIO 1.0 device >> + transitional device (which can act both as legacy and non-legacy) >> >> Virtio 1.0 defines the fields of the virtqueues as little endian, >> while legacy uses guest's native endian [1]. Currently libvhost-user >> does not handle virtio endianness at all, i.e. it works only if the >> native endianness matches with whatever is actually needed. That means >> things break spectacularly on big-endian targets. Let us handle virtio >> endianness for non-legacy as required by the virtio specification >> [1]. > > Maybe add > > "and fence legacy virtio, as there is no safe way to figure out the > needed endianness conversions for all cases."
Okay. > >> The fencing of legacy virtio devices is done in >> `vu_set_features_exec`. > > Not that I disagree with fencing legacy virtio, but looking at some > vhost-user* drivers, I'm not sure everything will work as desired for > those (I might be missing something, though.) > > - vhost-user-blk lists VERSION_1 in the supported features, but > vhost-user-scsi doesn't... is there some inheritance going on that > I'm missing? > - vhost-user-gpu-pci inherits from virtio-gpu-pci, so I guess it's fine > - vhost-user-input should also always have been virtio-1 > > So, has anybody been using vhost-user-scsi and can confirm that it > still works, or at least can be made to work? Unfortunately, I don’t have the required hardware :/ Can please anybody verify this? > >> >> [1] >> https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/virtio-v1.1-cs01.html#x1-210003 >> >> Signed-off-by: Marc Hartmayer <[email protected]> >> --- >> contrib/libvhost-user/libvhost-user.c | 77 +++++++++++++++------------ >> 1 file changed, 43 insertions(+), 34 deletions(-) > > The code change per se LGTM. Thanks for the feedback! > -- Kind regards / Beste Grüße Marc Hartmayer IBM Deutschland Research & Development GmbH Vorsitzender des Aufsichtsrats: Gregor Pillen Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen Registergericht: Amtsgericht Stuttgart, HRB 243294
