On Tue, 16 Jan 2018 14:57:03 +0800 Dong Jia Shi <bjsdjshi@xxxxxxxxxxxxxxxxxx> wrote: > * Cornelia Huck <cohuck@xxxxxxxxxx> [2018-01-15 11:43:53 +0100]: > > > The vfio-ccw documentation comes from the cover letter of the > > original patch submission, which shows in some parts. Give it some > > love; in particular: > > > > - Remove/rework statements that make sense in a cover letter, but not > > in regular documentation. > > - Fix some typos. > > - Describe the current limitations in more detail. > Nice. > > > > > Signed-off-by: Cornelia Huck <cohuck@xxxxxxxxxx> > > --- > > Documentation/s390/vfio-ccw.txt | 78 +++++++++++++++++++---------------------- > > 1 file changed, 37 insertions(+), 41 deletions(-) > > > > diff --git a/Documentation/s390/vfio-ccw.txt b/Documentation/s390/vfio-ccw.txt > > index 90b3dfead81b..c3dfbdcf0c8d 100644 > > --- a/Documentation/s390/vfio-ccw.txt > > +++ b/Documentation/s390/vfio-ccw.txt > > @@ -28,7 +28,7 @@ every detail. More information/reference could be found here: > > https://en.wikipedia.org/wiki/Channel_I/O > > - s390 architecture: > > s390 Principles of Operation manual (IBM Form. No. SA22-7832) > > -- The existing Qemu code which implements a simple emulated channel > > +- The existing QEMU code which implements a simple emulated channel > > subsystem could also be a good reference. It makes it easier to follow > > the flow. > > qemu/hw/s390x/css.c > > @@ -39,22 +39,21 @@ For vfio mediated device framework: > > Motivation of vfio-ccw > > ---------------------- > > > > -Currently, a guest virtualized via qemu/kvm on s390 only sees > > +Typically, a guest virtualized via qemu/kvm on s390 only sees > No need to s/qemu/QEMU/ here? Ah, I looked only for Qemu, not qemu. I'll make that QEMU/KVM. > > > paravirtualized virtio devices via the "Virtio Over Channel I/O > > (virtio-ccw)" transport. This makes virtio devices discoverable via > > standard operating system algorithms for handling channel devices. > > > > However this is not enough. On s390 for the majority of devices, which > > use the standard Channel I/O based mechanism, we also need to provide > > -the functionality of passing through them to a Qemu virtual machine. > > +the functionality of passing through them to a QEMU virtual machine. > > This includes devices that don't have a virtio counterpart (e.g. tape > > drives) or that have specific characteristics which guests want to > > exploit. > > > > For passing a device to a guest, we want to use the same interface as > > -everybody else, namely vfio. Thus, we would like to introduce vfio > > -support for channel devices. And we would like to name this new vfio > > -device "vfio-ccw". > > +everybody else, namely vfio. We implement this vfio support for channel > > +devices via the vfio device "vfio-ccw". > The vfio-ccw device implementation was used in one iteration in the > passed. We now implement via the mediated device stuff, and vfio-ccw > subchannel device driver. So, how about changing the above line to: > devices via the vfio mediated device framework and the new added > subchannel device driver "vfio_ccw". OK, will change that. > > Otherwise, LGTM. Thanks for looking!
