On Tue, 17 Jun 2014 14:06:25 +0200 Alexander Graf <ag...@suse.de> wrote:
> > On 17.06.14 14:04, Cornelia Huck wrote: > > On Tue, 17 Jun 2014 18:45:09 +0800 > > Ming Lei <ming....@canonical.com> wrote: > > > >> On Tue, Jun 17, 2014 at 6:40 PM, Ming Lei <ming....@canonical.com> wrote: > >>> On Tue, Jun 17, 2014 at 6:25 PM, Cornelia Huck <cornelia.h...@de.ibm.com> > >>> wrote: > >>>> On Tue, 17 Jun 2014 18:15:39 +0800 > >>>> Ming Lei <ming....@canonical.com> wrote: > >>>> > >>>>> On Tue, Jun 17, 2014 at 4:46 PM, Cornelia Huck > >>>>> <cornelia.h...@de.ibm.com> wrote: > >>>>>>> Looks like s390 virtio-blk never enables the two common features, is > >>>>>>> there any reason the two features can't be supported by s390? > >>>>>> Indirect descriptors are fine. event_idx will not work IIUC because we > >>>>>> always need to do a sync before we see changes, and this needs an > >>>>>> interrupt to trigger. > >>>>> Sounds like the old s390 isn't cache coherent? Because you mean > >>>>> write in one side can only be observed from another side with an > >>>>> explicit notification or interrupt. > >>>>> > >>>>> On arm/arm64, we didn't see any problem with event_idx. > >>>> But you probably have the queues in guest memory, as on other > >>>> transports (including virtio-ccw)? The old s390-virtio transport keeps > >>>> the devices and their virtqueues in a memory area behind the guest > >>>> memory - the guest does not see that memory directly, but a sync has to > >>>> be performed to see virtqueue movement (see s390_virtio_device_sync()). > >>> OK, it looks like a real physical device, :-) > >>> > >>> I will keep s390-virtio as it is, thanks for your explanation. > >> BTW, do you want me to add DEFINE_VIRTIO_COMMON_FEATURES() > >> to s390_virtio_net_properties and s390_virtio_scsi_properties since > >> I remove them from their default properties? > > It might be better to remove them for good :) > > > > Nobody has probably tried to use them for some time... > > I just start a very minimal guest with a virtio-console and a > > virtio-blk device. Don't know whether Alex has a more advanced setup > > at hand? > > It's the only target that works with TCG, no? Yup. Do you have a test setup with net, scsi, ...? I usually test networking (for example) only via a libvirt setup, which will only work with virtio-ccw.
