On Thu, Aug 9, 2012 at 1:12 PM, Cornelia Huck <cornelia.huck@xxxxxxxxxx> wrote: > On Thu, 9 Aug 2012 12:34:04 +0100 > Stefan Hajnoczi <stefanha@xxxxxxxxx> wrote: > >> On Tue, Aug 7, 2012 at 3:52 PM, Cornelia Huck <cornelia.huck@xxxxxxxxxx> wrote: >> > Add a new virtio transport that uses channel commands to perform >> > virtio operations. >> > >> > Add a new machine type s390-ccw that uses this virtio-ccw transport >> > and make it the default machine for s390. >> > >> > Signed-off-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx> >> > --- >> > hw/qdev-monitor.c | 5 + >> > hw/s390-virtio.c | 268 ++++++++++---- >> > hw/s390x/Makefile.objs | 1 + >> > hw/s390x/virtio-ccw.c | 962 +++++++++++++++++++++++++++++++++++++++++++++++++ >> > hw/s390x/virtio-ccw.h | 77 ++++ >> > vl.c | 1 + >> > 6 files changed, 1243 insertions(+), 71 deletions(-) >> > create mode 100644 hw/s390x/virtio-ccw.c >> > create mode 100644 hw/s390x/virtio-ccw.h >> >> Is the virtqueue still using vring and assuming the hypervisor reaches >> into guest memory? > > The virtqueues are guest-allocated and their location is transmitted > via a control-type ccw to the host, which can then use it until > notified otherwise. > >> >> Can existing ccw device types access memory directly (for some reason >> I assumed ccw always copies or send messages)? > > Not sure if I understand your question correctly, but read or write > type ccws specify a memory area where the hardware/hypervisor may write > to or read from. These accesses happen while the channel program is > running (any time between the ssch/rsch and ending status present at > the subchannel). The "specify an area that can be used by hardware and > os" approach exists as well; the closed thing to the virtio-ccw > approach is probably qdio. Okay, thanks! Stefan -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
